Contract Address Details

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {InheritERC404} from "./InheritERC404.sol";
import {Strings} from "@openzeppelin/contracts/utils/Strings.sol";

contract WFFToken404 is InheritERC404 {

    function mint(
        address account_,
        uint256 value_
    ) public override onlyRole(MINTER_ROLE) {
        _mintERC20(account_, value_);
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), "ERC721Metadata: URI query for non-existent token");

        string memory baseURI = _baseURI();
        return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI)) : "";
    }

    function supportsInterface(bytes4 interfaceId)
        public
        view
        override
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }
}
        

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/SignedMath.sol)

pragma solidity ^0.8.0;

/**
 * @dev Standard signed math utilities missing in the Solidity language.
 */
library SignedMathUpgradeable {
    /**
     * @dev Returns the largest of two signed numbers.
     */
    function max(int256 a, int256 b) internal pure returns (int256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two signed numbers.
     */
    function min(int256 a, int256 b) internal pure returns (int256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two signed numbers without overflow.
     * The result is rounded towards zero.
     */
    function average(int256 a, int256 b) internal pure returns (int256) {
        // Formula from the book "Hacker's Delight"
        int256 x = (a & b) + ((a ^ b) >> 1);
        return x + (int256(uint256(x) >> 255) & (a ^ b));
    }

    /**
     * @dev Returns the absolute unsigned value of a signed value.
     */
    function abs(int256 n) internal pure returns (uint256) {
        unchecked {
            // must be unchecked in order to support `n = type(int256).min`
            return uint256(n >= 0 ? n : -n);
        }
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Strings.sol)

pragma solidity ^0.8.0;

import "./math/Math.sol";
import "./math/SignedMath.sol";

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _SYMBOLS = "0123456789abcdef";
    uint8 private constant _ADDRESS_LENGTH = 20;

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        unchecked {
            uint256 length = Math.log10(value) + 1;
            string memory buffer = new string(length);
            uint256 ptr;
            /// @solidity memory-safe-assembly
            assembly {
                ptr := add(buffer, add(32, length))
            }
            while (true) {
                ptr--;
                /// @solidity memory-safe-assembly
                assembly {
                    mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
                }
                value /= 10;
                if (value == 0) break;
            }
            return buffer;
        }
    }

    /**
     * @dev Converts a `int256` to its ASCII `string` decimal representation.
     */
    function toString(int256 value) internal pure returns (string memory) {
        return string(abi.encodePacked(value < 0 ? "-" : "", toString(SignedMath.abs(value))));
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        unchecked {
            return toHexString(value, Math.log256(value) + 1);
        }
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }

    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
    }

    /**
     * @dev Returns true if the two strings are equal.
     */
    function equal(string memory a, string memory b) internal pure returns (bool) {
        return keccak256(bytes(a)) == keccak256(bytes(b));
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (proxy/ERC1967/ERC1967Upgrade.sol)

pragma solidity ^0.8.2;

import "../beacon/IBeaconUpgradeable.sol";
import "../../interfaces/IERC1967Upgradeable.sol";
import "../../interfaces/draft-IERC1822Upgradeable.sol";
import "../../utils/AddressUpgradeable.sol";
import "../../utils/StorageSlotUpgradeable.sol";
import {Initializable} from "../utils/Initializable.sol";

/**
 * @dev This abstract contract provides getters and event emitting update functions for
 * https://eips.ethereum.org/EIPS/eip-1967[EIP1967] slots.
 *
 * _Available since v4.1._
 */
abstract contract ERC1967UpgradeUpgradeable is Initializable, IERC1967Upgradeable {
    // This is the keccak-256 hash of "eip1967.proxy.rollback" subtracted by 1
    bytes32 private constant _ROLLBACK_SLOT = 0x4910fdfa16fed3260ed0e7147f7cc6da11a60208b5b9406d12a635614ffd9143;

    /**
     * @dev Storage slot with the address of the current implementation.
     * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
     * validated in the constructor.
     */
    bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

    function __ERC1967Upgrade_init() internal onlyInitializing {
    }

    function __ERC1967Upgrade_init_unchained() internal onlyInitializing {
    }
    /**
     * @dev Returns the current implementation address.
     */
    function _getImplementation() internal view returns (address) {
        return StorageSlotUpgradeable.getAddressSlot(_IMPLEMENTATION_SLOT).value;
    }

    /**
     * @dev Stores a new address in the EIP1967 implementation slot.
     */
    function _setImplementation(address newImplementation) private {
        require(AddressUpgradeable.isContract(newImplementation), "ERC1967: new implementation is not a contract");
        StorageSlotUpgradeable.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
    }

    /**
     * @dev Perform implementation upgrade
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeTo(address newImplementation) internal {
        _setImplementation(newImplementation);
        emit Upgraded(newImplementation);
    }

    /**
     * @dev Perform implementation upgrade with additional setup call.
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeToAndCall(address newImplementation, bytes memory data, bool forceCall) internal {
        _upgradeTo(newImplementation);
        if (data.length > 0 || forceCall) {
            AddressUpgradeable.functionDelegateCall(newImplementation, data);
        }
    }

    /**
     * @dev Perform implementation upgrade with security checks for UUPS proxies, and additional setup call.
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeToAndCallUUPS(address newImplementation, bytes memory data, bool forceCall) internal {
        // Upgrades from old implementations will perform a rollback test. This test requires the new
        // implementation to upgrade back to the old, non-ERC1822 compliant, implementation. Removing
        // this special case will break upgrade paths from old UUPS implementation to new ones.
        if (StorageSlotUpgradeable.getBooleanSlot(_ROLLBACK_SLOT).value) {
            _setImplementation(newImplementation);
        } else {
            try IERC1822ProxiableUpgradeable(newImplementation).proxiableUUID() returns (bytes32 slot) {
                require(slot == _IMPLEMENTATION_SLOT, "ERC1967Upgrade: unsupported proxiableUUID");
            } catch {
                revert("ERC1967Upgrade: new implementation is not UUPS");
            }
            _upgradeToAndCall(newImplementation, data, forceCall);
        }
    }

    /**
     * @dev Storage slot with the admin of the contract.
     * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
     * validated in the constructor.
     */
    bytes32 internal constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;

    /**
     * @dev Returns the current admin.
     */
    function _getAdmin() internal view returns (address) {
        return StorageSlotUpgradeable.getAddressSlot(_ADMIN_SLOT).value;
    }

    /**
     * @dev Stores a new address in the EIP1967 admin slot.
     */
    function _setAdmin(address newAdmin) private {
        require(newAdmin != address(0), "ERC1967: new admin is the zero address");
        StorageSlotUpgradeable.getAddressSlot(_ADMIN_SLOT).value = newAdmin;
    }

    /**
     * @dev Changes the admin of the proxy.
     *
     * Emits an {AdminChanged} event.
     */
    function _changeAdmin(address newAdmin) internal {
        emit AdminChanged(_getAdmin(), newAdmin);
        _setAdmin(newAdmin);
    }

    /**
     * @dev The storage slot of the UpgradeableBeacon contract which defines the implementation for this proxy.
     * This is bytes32(uint256(keccak256('eip1967.proxy.beacon')) - 1)) and is validated in the constructor.
     */
    bytes32 internal constant _BEACON_SLOT = 0xa3f0ad74e5423aebfd80d3ef4346578335a9a72aeaee59ff6cb3582b35133d50;

    /**
     * @dev Returns the current beacon.
     */
    function _getBeacon() internal view returns (address) {
        return StorageSlotUpgradeable.getAddressSlot(_BEACON_SLOT).value;
    }

    /**
     * @dev Stores a new beacon in the EIP1967 beacon slot.
     */
    function _setBeacon(address newBeacon) private {
        require(AddressUpgradeable.isContract(newBeacon), "ERC1967: new beacon is not a contract");
        require(
            AddressUpgradeable.isContract(IBeaconUpgradeable(newBeacon).implementation()),
            "ERC1967: beacon implementation is not a contract"
        );
        StorageSlotUpgradeable.getAddressSlot(_BEACON_SLOT).value = newBeacon;
    }

    /**
     * @dev Perform beacon upgrade with additional setup call. Note: This upgrades the address of the beacon, it does
     * not upgrade the implementation contained in the beacon (see {UpgradeableBeacon-_setImplementation} for that).
     *
     * Emits a {BeaconUpgraded} event.
     */
    function _upgradeBeaconToAndCall(address newBeacon, bytes memory data, bool forceCall) internal {
        _setBeacon(newBeacon);
        emit BeaconUpgraded(newBeacon);
        if (data.length > 0 || forceCall) {
            AddressUpgradeable.functionDelegateCall(IBeaconUpgradeable(newBeacon).implementation(), data);
        }
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (proxy/utils/UUPSUpgradeable.sol)

pragma solidity ^0.8.0;

import "../../interfaces/draft-IERC1822Upgradeable.sol";
import "../ERC1967/ERC1967UpgradeUpgradeable.sol";
import {Initializable} from "./Initializable.sol";

/**
 * @dev An upgradeability mechanism designed for UUPS proxies. The functions included here can perform an upgrade of an
 * {ERC1967Proxy}, when this contract is set as the implementation behind such a proxy.
 *
 * A security mechanism ensures that an upgrade does not turn off upgradeability accidentally, although this risk is
 * reinstated if the upgrade retains upgradeability but removes the security mechanism, e.g. by replacing
 * `UUPSUpgradeable` with a custom implementation of upgrades.
 *
 * The {_authorizeUpgrade} function must be overridden to include access restriction to the upgrade mechanism.
 *
 * _Available since v4.1._
 */
abstract contract UUPSUpgradeable is Initializable, IERC1822ProxiableUpgradeable, ERC1967UpgradeUpgradeable {
    /// @custom:oz-upgrades-unsafe-allow state-variable-immutable state-variable-assignment
    address private immutable __self = address(this);

    /**
     * @dev Check that the execution is being performed through a delegatecall call and that the execution context is
     * a proxy contract with an implementation (as defined in ERC1967) pointing to self. This should only be the case
     * for UUPS and transparent proxies that are using the current contract as their implementation. Execution of a
     * function through ERC1167 minimal proxies (clones) would not normally pass this test, but is not guaranteed to
     * fail.
     */
    modifier onlyProxy() {
        require(address(this) != __self, "Function must be called through delegatecall");
        require(_getImplementation() == __self, "Function must be called through active proxy");
        _;
    }

    /**
     * @dev Check that the execution is not being performed through a delegate call. This allows a function to be
     * callable on the implementing contract but not through proxies.
     */
    modifier notDelegated() {
        require(address(this) == __self, "UUPSUpgradeable: must not be called through delegatecall");
        _;
    }

    function __UUPSUpgradeable_init() internal onlyInitializing {
    }

    function __UUPSUpgradeable_init_unchained() internal onlyInitializing {
    }
    /**
     * @dev Implementation of the ERC1822 {proxiableUUID} function. This returns the storage slot used by the
     * implementation. It is used to validate the implementation's compatibility when performing an upgrade.
     *
     * IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks
     * bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this
     * function revert if invoked through a proxy. This is guaranteed by the `notDelegated` modifier.
     */
    function proxiableUUID() external view virtual override notDelegated returns (bytes32) {
        return _IMPLEMENTATION_SLOT;
    }

    /**
     * @dev Upgrade the implementation of the proxy to `newImplementation`.
     *
     * Calls {_authorizeUpgrade}.
     *
     * Emits an {Upgraded} event.
     *
     * @custom:oz-upgrades-unsafe-allow-reachable delegatecall
     */
    function upgradeTo(address newImplementation) public virtual onlyProxy {
        _authorizeUpgrade(newImplementation);
        _upgradeToAndCallUUPS(newImplementation, new bytes(0), false);
    }

    /**
     * @dev Upgrade the implementation of the proxy to `newImplementation`, and subsequently execute the function call
     * encoded in `data`.
     *
     * Calls {_authorizeUpgrade}.
     *
     * Emits an {Upgraded} event.
     *
     * @custom:oz-upgrades-unsafe-allow-reachable delegatecall
     */
    function upgradeToAndCall(address newImplementation, bytes memory data) public payable virtual onlyProxy {
        _authorizeUpgrade(newImplementation);
        _upgradeToAndCallUUPS(newImplementation, data, true);
    }

    /**
     * @dev Function that should revert when `msg.sender` is not authorized to upgrade the contract. Called by
     * {upgradeTo} and {upgradeToAndCall}.
     *
     * Normally, this function will use an xref:access.adoc[access control] modifier such as {Ownable-onlyOwner}.
     *
     * ```solidity
     * function _authorizeUpgrade(address) internal override onlyOwner {}
     * ```
     */
    function _authorizeUpgrade(address newImplementation) internal virtual;

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}
          

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {IERC721Receiver} from "@openzeppelin/contracts/interfaces/IERC721Receiver.sol";
import {IERC165} from "@openzeppelin/contracts/interfaces/IERC165.sol";
import {IERC404} from "./interfaces/IERC404.sol";
import {DoubleEndedQueue} from "./lib/DoubleEndedQueue.sol";
import {ERC721Events} from "./lib/ERC721Events.sol";
import {ERC20Events} from "./lib/ERC20Events.sol";

abstract contract ERC404 is IERC404 {
  using DoubleEndedQueue for DoubleEndedQueue.Uint256Deque;

  /// @dev The queue of ERC-721 tokens stored in the contract.
  DoubleEndedQueue.Uint256Deque private _storedERC721Ids;

  /// @dev Token name
  string public name;

  /// @dev Token symbol
  string public symbol;

  /// @dev Decimals for ERC-20 representation
  uint8 public immutable decimals;

  /// @dev Units for ERC-20 representation
  uint256 public immutable units;

  /// @dev Total supply in ERC-20 representation
  uint256 public totalSupply;

  /// @dev Current mint counter which also represents the highest
  ///      minted id, monotonically increasing to ensure accurate ownership
  uint256 public minted;

  /// @dev Initial chain id for EIP-2612 support
  uint256 internal immutable _INITIAL_CHAIN_ID;

  /// @dev Initial domain separator for EIP-2612 support
  bytes32 internal immutable _INITIAL_DOMAIN_SEPARATOR;

  /// @dev Balance of user in ERC-20 representation
  mapping(address => uint256) public balanceOf;

  /// @dev Allowance of user in ERC-20 representation
  mapping(address => mapping(address => uint256)) public allowance;

  /// @dev Approval in ERC-721 representaion
  mapping(uint256 => address) public getApproved;

  /// @dev Approval for all in ERC-721 representation
  mapping(address => mapping(address => bool)) public isApprovedForAll;

  /// @dev Packed representation of ownerOf and owned indices
  mapping(uint256 => uint256) internal _ownedData;

  /// @dev Array of owned ids in ERC-721 representation
  mapping(address => uint256[]) internal _owned;

  /// @dev Addresses that are exempt from ERC-721 transfer, typically for gas savings (pairs, routers, etc)
  mapping(address => bool) internal _erc721TransferExempt;

  /// @dev EIP-2612 nonces
  mapping(address => uint256) public nonces;

  /// @dev Address bitmask for packed ownership data
  uint256 private constant _BITMASK_ADDRESS = (1 << 160) - 1;

  /// @dev Owned index bitmask for packed ownership data
  uint256 private constant _BITMASK_OWNED_INDEX = ((1 << 96) - 1) << 160;

  /// @dev Constant for token id encoding
  uint256 public constant ID_ENCODING_PREFIX = 1 << 255;

  constructor(string memory name_, string memory symbol_, uint8 decimals_) {
    name = name_;
    symbol = symbol_;

    if (decimals_ < 18) {
      revert DecimalsTooLow();
    }

    decimals = decimals_;
    units = 10 ** decimals;

    // EIP-2612 initialization
    _INITIAL_CHAIN_ID = block.chainid;
    _INITIAL_DOMAIN_SEPARATOR = _computeDomainSeparator();
  }

  /// @notice Function to find owner of a given ERC-721 token
  function ownerOf(
    uint256 id_
  ) public view virtual returns (address erc721Owner) {
    erc721Owner = _getOwnerOf(id_);

    if (!_isValidTokenId(id_)) {
      revert InvalidTokenId();
    }

    if (erc721Owner == address(0)) {
      revert NotFound();
    }
  }

  function owned(
    address owner_
  ) public view virtual returns (uint256[] memory) {
    return _owned[owner_];
  }

  function erc721BalanceOf(
    address owner_
  ) public view virtual returns (uint256) {
    return _owned[owner_].length;
  }

  function erc20BalanceOf(
    address owner_
  ) public view virtual returns (uint256) {
    return balanceOf[owner_];
  }

  function erc20TotalSupply() public view virtual returns (uint256) {
    return totalSupply;
  }

  function erc721TotalSupply() public view virtual returns (uint256) {
    return minted;
  }

  function getERC721QueueLength() public view virtual returns (uint256) {
    return _storedERC721Ids.length();
  }

  function getERC721TokensInQueue(
    uint256 start_,
    uint256 count_
  ) public view virtual returns (uint256[] memory) {
    uint256[] memory tokensInQueue = new uint256[](count_);

    for (uint256 i = start_; i < start_ + count_; ) {
      tokensInQueue[i - start_] = _storedERC721Ids.at(i);

      unchecked {
        ++i;
      }
    }

    return tokensInQueue;
  }

  /// @notice tokenURI must be implemented by child contract
  function tokenURI(uint256 id_) public view virtual returns (string memory);

  /// @notice Function for token approvals
  /// @dev This function assumes the operator is attempting to approve
  ///      an ERC-721 if valueOrId_ is a possibly valid ERC-721 token id.
  ///      Unlike setApprovalForAll, spender_ must be allowed to be 0x0 so
  ///      that approval can be revoked.
  function approve(
    address spender_,
    uint256 valueOrId_
  ) public virtual returns (bool) {
    if (_isValidTokenId(valueOrId_)) {
      erc721Approve(spender_, valueOrId_);
    } else {
      return erc20Approve(spender_, valueOrId_);
    }

    return true;
  }

  function erc721Approve(address spender_, uint256 id_) public virtual {
    // Intention is to approve as ERC-721 token (id).
    address erc721Owner = _getOwnerOf(id_);

    if (
      msg.sender != erc721Owner && !isApprovedForAll[erc721Owner][msg.sender]
    ) {
      revert Unauthorized();
    }

    getApproved[id_] = spender_;

    emit ERC721Events.Approval(erc721Owner, spender_, id_);
  }

  /// @dev Providing type(uint256).max for approval value results in an
  ///      unlimited approval that is not deducted from on transfers.
  function erc20Approve(
    address spender_,
    uint256 value_
  ) public virtual returns (bool) {
    // Prevent granting 0x0 an ERC-20 allowance.
    if (spender_ == address(0)) {
      revert InvalidSpender();
    }

    allowance[msg.sender][spender_] = value_;

    emit ERC20Events.Approval(msg.sender, spender_, value_);

    return true;
  }

  /// @notice Function for ERC-721 approvals
  function setApprovalForAll(address operator_, bool approved_) public virtual {
    // Prevent approvals to 0x0.
    if (operator_ == address(0)) {
      revert InvalidOperator();
    }
    isApprovedForAll[msg.sender][operator_] = approved_;
    emit ERC721Events.ApprovalForAll(msg.sender, operator_, approved_);
  }

  /// @notice Function for mixed transfers from an operator that may be different than 'from'.
  /// @dev This function assumes the operator is attempting to transfer an ERC-721
  ///      if valueOrId is a possible valid token id.
  function transferFrom(
    address from_,
    address to_,
    uint256 valueOrId_
  ) public virtual returns (bool) {
    if (_isValidTokenId(valueOrId_)) {
      erc721TransferFrom(from_, to_, valueOrId_);
    } else {
      // Intention is to transfer as ERC-20 token (value).
      return erc20TransferFrom(from_, to_, valueOrId_);
    }

    return true;
  }

  /// @notice Function for ERC-721 transfers from.
  /// @dev This function is recommended for ERC721 transfers.
  function erc721TransferFrom(
    address from_,
    address to_,
    uint256 id_
  ) public virtual {
    // Prevent minting tokens from 0x0.
    if (from_ == address(0)) {
      revert InvalidSender();
    }

    // Prevent burning tokens to 0x0.
    if (to_ == address(0)) {
      revert InvalidRecipient();
    }

    if (from_ != _getOwnerOf(id_)) {
      revert Unauthorized();
    }

    // Check that the operator is either the sender or approved for the transfer.
    if (
      msg.sender != from_ &&
      !isApprovedForAll[from_][msg.sender] &&
      msg.sender != getApproved[id_]
    ) {
      revert Unauthorized();
    }

    // We only need to check ERC-721 transfer exempt status for the recipient 
    // since the sender being ERC-721 transfer exempt means they have already 
    // had their ERC-721s stripped away during the rebalancing process.
    if (erc721TransferExempt(to_)) {
      revert RecipientIsERC721TransferExempt();
    }

    // Transfer 1 * units ERC-20 and 1 ERC-721 token.
    // ERC-721 transfer exemptions handled above. Can't make it to this point if either is transfer exempt.
    _transferERC20(from_, to_, units);
    _transferERC721(from_, to_, id_);
  }

  /// @notice Function for ERC-20 transfers from.
  /// @dev This function is recommended for ERC20 transfers
  function erc20TransferFrom(
    address from_,
    address to_,
    uint256 value_
  ) public virtual returns (bool) {
    // Prevent minting tokens from 0x0.
    if (from_ == address(0)) {
      revert InvalidSender();
    }

    // Prevent burning tokens to 0x0.
    if (to_ == address(0)) {
      revert InvalidRecipient();
    }

    uint256 allowed = allowance[from_][msg.sender];

    // Check that the operator has sufficient allowance.
    if (allowed != type(uint256).max) {
      allowance[from_][msg.sender] = allowed - value_;
    }

    // Transferring ERC-20s directly requires the _transferERC20WithERC721 function.
    // Handles ERC-721 exemptions internally.
    return _transferERC20WithERC721(from_, to_, value_);
  }

  /// @notice Function for ERC-20 transfers.
  /// @dev This function assumes the operator is attempting to transfer as ERC-20
  ///      given this function is only supported on the ERC-20 interface.
  ///      Treats even large amounts that are valid ERC-721 ids as ERC-20s.
  function transfer(address to_, uint256 value_) public virtual returns (bool) {
    // Prevent burning tokens to 0x0.
    if (to_ == address(0)) {
      revert InvalidRecipient();
    }

    // Transferring ERC-20s directly requires the _transferERC20WithERC721 function.
    // Handles ERC-721 exemptions internally.
    return _transferERC20WithERC721(msg.sender, to_, value_);
  }

  /// @notice Function for ERC-721 transfers with contract support.
  /// This function only supports moving valid ERC-721 ids, as it does not exist on the ERC-20
  /// spec and will revert otherwise.
  function safeTransferFrom(
    address from_,
    address to_,
    uint256 id_
  ) public virtual {
    safeTransferFrom(from_, to_, id_, "");
  }

  /// @notice Function for ERC-721 transfers with contract support and callback data.
  /// This function only supports moving valid ERC-721 ids, as it does not exist on the
  /// ERC-20 spec and will revert otherwise.
  function safeTransferFrom(
    address from_,
    address to_,
    uint256 id_,
    bytes memory data_
  ) public virtual {
    if (!_isValidTokenId(id_)) {
      revert InvalidTokenId();
    }

    transferFrom(from_, to_, id_);

    if (
      to_.code.length != 0 &&
      IERC721Receiver(to_).onERC721Received(msg.sender, from_, id_, data_) !=
      IERC721Receiver.onERC721Received.selector
    ) {
      revert UnsafeRecipient();
    }
  }

  /// @notice Function for EIP-2612 permits (ERC-20 only).
  /// @dev Providing type(uint256).max for permit value results in an
  ///      unlimited approval that is not deducted from on transfers.
  function permit(
    address owner_,
    address spender_,
    uint256 value_,
    uint256 deadline_,
    uint8 v_,
    bytes32 r_,
    bytes32 s_
  ) public virtual {
    if (deadline_ < block.timestamp) {
      revert PermitDeadlineExpired();
    }

    // permit cannot be used for ERC-721 token approvals, so ensure
    // the value does not fall within the valid range of ERC-721 token ids.
    if (_isValidTokenId(value_)) {
      revert InvalidApproval();
    }

    if (spender_ == address(0)) {
      revert InvalidSpender();
    }

    unchecked {
      address recoveredAddress = ecrecover(
        keccak256(
          abi.encodePacked(
            "\x19\x01",
            DOMAIN_SEPARATOR(),
            keccak256(
              abi.encode(
                keccak256(
                  "Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)"
                ),
                owner_,
                spender_,
                value_,
                nonces[owner_]++,
                deadline_
              )
            )
          )
        ),
        v_,
        r_,
        s_
      );

      if (recoveredAddress == address(0) || recoveredAddress != owner_) {
        revert InvalidSigner();
      }

      allowance[recoveredAddress][spender_] = value_;
    }

    emit ERC20Events.Approval(owner_, spender_, value_);
  }

  /// @notice Returns domain initial domain separator, or recomputes if chain id is not equal to initial chain id
  function DOMAIN_SEPARATOR() public view virtual returns (bytes32) {
    return
      block.chainid == _INITIAL_CHAIN_ID
        ? _INITIAL_DOMAIN_SEPARATOR
        : _computeDomainSeparator();
  }

  function supportsInterface(
    bytes4 interfaceId
  ) public view virtual returns (bool) {
    return
      interfaceId == type(IERC404).interfaceId ||
      interfaceId == type(IERC165).interfaceId;
  }

  /// @notice Function for self-exemption
  function setSelfERC721TransferExempt(bool state_) public virtual {
    _setERC721TransferExempt(msg.sender, state_);
  }

  /// @notice Function to check if address is transfer exempt
  function erc721TransferExempt(
    address target_
  ) public view virtual returns (bool) {
    return target_ == address(0) || _erc721TransferExempt[target_];
  }

  /// @notice For a token token id to be considered valid, it just needs
  ///         to fall within the range of possible token ids, it does not
  ///         necessarily have to be minted yet.
  function _isValidTokenId(uint256 id_) internal pure returns (bool) {
    return id_ > ID_ENCODING_PREFIX && id_ != type(uint256).max;
  }

  /// @notice Internal function to compute domain separator for EIP-2612 permits
  function _computeDomainSeparator() internal view virtual returns (bytes32) {
    return
      keccak256(
        abi.encode(
          keccak256(
            "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"
          ),
          keccak256(bytes(name)),
          keccak256("1"),
          block.chainid,
          address(this)
        )
      );
  }

  /// @notice This is the lowest level ERC-20 transfer function, which
  ///         should be used for both normal ERC-20 transfers as well as minting.
  /// Note that this function allows transfers to and from 0x0.
  function _transferERC20(
    address from_,
    address to_,
    uint256 value_
  ) internal virtual {
    // Minting is a special case for which we should not check the balance of
    // the sender, and we should increase the total supply.
    if (from_ == address(0)) {
      totalSupply += value_;
    } else {
      // Deduct value from sender's balance.
      balanceOf[from_] -= value_;
    }

    // Update the recipient's balance.
    // Can be unchecked because on mint, adding to totalSupply is checked, and on transfer balance deduction is checked.
    unchecked {
      balanceOf[to_] += value_;
    }

    emit ERC20Events.Transfer(from_, to_, value_);
  }

  /// @notice Consolidated record keeping function for transferring ERC-721s.
  /// @dev Assign the token to the new owner, and remove from the old owner.
  /// Note that this function allows transfers to and from 0x0.
  /// Does not handle ERC-721 exemptions.
  function _transferERC721(
    address from_,
    address to_,
    uint256 id_
  ) internal virtual {
    // If this is not a mint, handle record keeping for transfer from previous owner.
    if (from_ != address(0)) {
      // On transfer of an NFT, any previous approval is reset.
      delete getApproved[id_];

      uint256 updatedId = _owned[from_][_owned[from_].length - 1];
      if (updatedId != id_) {
        uint256 updatedIndex = _getOwnedIndex(id_);
        // update _owned for sender
        _owned[from_][updatedIndex] = updatedId;
        // update index for the moved id
        _setOwnedIndex(updatedId, updatedIndex);
      }

      // pop
      _owned[from_].pop();
    }

    // Check if this is a burn.
    if (to_ != address(0)) {
      // If not a burn, update the owner of the token to the new owner.
      // Update owner of the token to the new owner.
      _setOwnerOf(id_, to_);
      // Push token onto the new owner's stack.
      _owned[to_].push(id_);
      // Update index for new owner's stack.
      _setOwnedIndex(id_, _owned[to_].length - 1);
    } else {
      // If this is a burn, reset the owner of the token to 0x0 by deleting the token from _ownedData.
      delete _ownedData[id_];
    }

    emit ERC721Events.Transfer(from_, to_, id_);
  }

  /// @notice Internal function for ERC-20 transfers. Also handles any ERC-721 transfers that may be required.
  // Handles ERC-721 exemptions.
  function _transferERC20WithERC721(
    address from_,
    address to_,
    uint256 value_
  ) internal virtual returns (bool) {
    uint256 erc20BalanceOfSenderBefore = erc20BalanceOf(from_);
    uint256 erc20BalanceOfReceiverBefore = erc20BalanceOf(to_);

    _transferERC20(from_, to_, value_);

    // Preload for gas savings on branches
    bool isFromERC721TransferExempt = erc721TransferExempt(from_);
    bool isToERC721TransferExempt = erc721TransferExempt(to_);

    // Skip _withdrawAndStoreERC721 and/or _retrieveOrMintERC721 for ERC-721 transfer exempt addresses
    // 1) to save gas
    // 2) because ERC-721 transfer exempt addresses won't always have/need ERC-721s corresponding to their ERC20s.
    if (isFromERC721TransferExempt && isToERC721TransferExempt) {
      // Case 1) Both sender and recipient are ERC-721 transfer exempt. No ERC-721s need to be transferred.
      // NOOP.
    } else if (isFromERC721TransferExempt) {
      // Case 2) The sender is ERC-721 transfer exempt, but the recipient is not. Contract should not attempt
      //         to transfer ERC-721s from the sender, but the recipient should receive ERC-721s
      //         from the bank/minted for any whole number increase in their balance.
      // Only cares about whole number increments.
      uint256 tokensToRetrieveOrMint = (balanceOf[to_] / units) -
        (erc20BalanceOfReceiverBefore / units);
      for (uint256 i = 0; i < tokensToRetrieveOrMint; ) {
        _retrieveOrMintERC721(to_);
        unchecked {
          ++i;
        }
      }
    } else if (isToERC721TransferExempt) {
      // Case 3) The sender is not ERC-721 transfer exempt, but the recipient is. Contract should attempt
      //         to withdraw and store ERC-721s from the sender, but the recipient should not
      //         receive ERC-721s from the bank/minted.
      // Only cares about whole number increments.
      uint256 tokensToWithdrawAndStore = (erc20BalanceOfSenderBefore / units) -
        (balanceOf[from_] / units);
      for (uint256 i = 0; i < tokensToWithdrawAndStore; ) {
        _withdrawAndStoreERC721(from_);
        unchecked {
          ++i;
        }
      }
    } else {
      // Case 4) Neither the sender nor the recipient are ERC-721 transfer exempt.
      // Strategy:
      // 1. First deal with the whole tokens. These are easy and will just be transferred.
      // 2. Look at the fractional part of the value:
      //   a) If it causes the sender to lose a whole token that was represented by an NFT due to a
      //      fractional part being transferred, withdraw and store an additional NFT from the sender.
      //   b) If it causes the receiver to gain a whole new token that should be represented by an NFT
      //      due to receiving a fractional part that completes a whole token, retrieve or mint an NFT to the recevier.

      // Whole tokens worth of ERC-20s get transferred as ERC-721s without any burning/minting.
      uint256 nftsToTransfer = value_ / units;
      for (uint256 i = 0; i < nftsToTransfer; ) {
        // Pop from sender's ERC-721 stack and transfer them (LIFO)
        uint256 indexOfLastToken = _owned[from_].length - 1;
        uint256 tokenId = _owned[from_][indexOfLastToken];
        _transferERC721(from_, to_, tokenId);
        unchecked {
          ++i;
        }
      }

      // If the transfer changes either the sender or the recipient's holdings from a fractional to a non-fractional
      // amount (or vice versa), adjust ERC-721s.

      // First check if the send causes the sender to lose a whole token that was represented by an ERC-721
      // due to a fractional part being transferred.
      //
      // Process:
      // Take the difference between the whole number of tokens before and after the transfer for the sender.
      // If that difference is greater than the number of ERC-721s transferred (whole units), then there was
      // an additional ERC-721 lost due to the fractional portion of the transfer.
      // If this is a self-send and the before and after balances are equal (not always the case but often),
      // then no ERC-721s will be lost here.
      if (
        erc20BalanceOfSenderBefore / units - erc20BalanceOf(from_) / units >
        nftsToTransfer
      ) {
        _withdrawAndStoreERC721(from_);
      }

      // Then, check if the transfer causes the receiver to gain a whole new token which requires gaining
      // an additional ERC-721.
      //
      // Process:
      // Take the difference between the whole number of tokens before and after the transfer for the recipient.
      // If that difference is greater than the number of ERC-721s transferred (whole units), then there was
      // an additional ERC-721 gained due to the fractional portion of the transfer.
      // Again, for self-sends where the before and after balances are equal, no ERC-721s will be gained here.
      if (
        erc20BalanceOf(to_) / units - erc20BalanceOfReceiverBefore / units >
        nftsToTransfer
      ) {
        _retrieveOrMintERC721(to_);
      }
    }

    return true;
  }

  /// @notice Internal function for ERC20 minting
  /// @dev This function will allow minting of new ERC20s.
  ///      If mintCorrespondingERC721s_ is true, and the recipient is not ERC-721 exempt, it will
  ///      also mint the corresponding ERC721s.
  /// Handles ERC-721 exemptions.
  function _mintERC20(address to_, uint256 value_) internal virtual {
    /// You cannot mint to the zero address (you can't mint and immediately burn in the same transfer).
    if (to_ == address(0)) {
      revert InvalidRecipient();
    }

    if (totalSupply + value_ > ID_ENCODING_PREFIX) {
      revert MintLimitReached();
    }

    _transferERC20WithERC721(address(0), to_, value_);
  }

  /// @notice Internal function for ERC-721 minting and retrieval from the bank.
  /// @dev This function will allow minting of new ERC-721s up to the total fractional supply. It will
  ///      first try to pull from the bank, and if the bank is empty, it will mint a new token.
  /// Does not handle ERC-721 exemptions.
  function _retrieveOrMintERC721(address to_) internal virtual {
    if (to_ == address(0)) {
      revert InvalidRecipient();
    }

    uint256 id;

    if (!_storedERC721Ids.empty()) {
      // If there are any tokens in the bank, use those first.
      // Pop off the end of the queue (FIFO).
      id = _storedERC721Ids.popBack();
    } else {
      // Otherwise, mint a new token, should not be able to go over the total fractional supply.
      ++minted;

      // Reserve max uint256 for approvals
      if (minted == type(uint256).max) {
        revert MintLimitReached();
      }

      id = ID_ENCODING_PREFIX + minted;
    }

    address erc721Owner = _getOwnerOf(id);

    // The token should not already belong to anyone besides 0x0 or this contract.
    // If it does, something is wrong, as this should never happen.
    if (erc721Owner != address(0)) {
      revert AlreadyExists();
    }

    // Transfer the token to the recipient, either transferring from the contract's bank or minting.
    // Does not handle ERC-721 exemptions.
    _transferERC721(erc721Owner, to_, id);
  }

  /// @notice Internal function for ERC-721 deposits to bank (this contract).
  /// @dev This function will allow depositing of ERC-721s to the bank, which can be retrieved by future minters.
  // Does not handle ERC-721 exemptions.
  function _withdrawAndStoreERC721(address from_) internal virtual {
    if (from_ == address(0)) {
      revert InvalidSender();
    }

    // Retrieve the latest token added to the owner's stack (LIFO).
    uint256 id = _owned[from_][_owned[from_].length - 1];

    // Transfer to 0x0.
    // Does not handle ERC-721 exemptions.
    _transferERC721(from_, address(0), id);

    // Record the token in the contract's bank queue.
    _storedERC721Ids.pushFront(id);
  }

  /// @notice Initialization function to set pairs / etc, saving gas by avoiding mint / burn on unnecessary targets
  function _setERC721TransferExempt(
    address target_,
    bool state_
  ) internal virtual {
    if (target_ == address(0)) {
      revert InvalidExemption();
    }

    // Adjust the ERC721 balances of the target to respect exemption rules.
    // Despite this logic, it is still recommended practice to exempt prior to the target
    // having an active balance.
    if (state_) {
      _clearERC721Balance(target_);
    } else {
      _reinstateERC721Balance(target_);
    }

    _erc721TransferExempt[target_] = state_;
  }

  /// @notice Function to reinstate balance on exemption removal
  function _reinstateERC721Balance(address target_) private {
    uint256 expectedERC721Balance = erc20BalanceOf(target_) / units;
    uint256 actualERC721Balance = erc721BalanceOf(target_);

    for (uint256 i = 0; i < expectedERC721Balance - actualERC721Balance; ) {
      // Transfer ERC721 balance in from pool
      _retrieveOrMintERC721(target_);
      unchecked {
        ++i;
      }
    }
  }

  /// @notice Function to clear balance on exemption inclusion
  function _clearERC721Balance(address target_) private {
    uint256 erc721Balance = erc721BalanceOf(target_);

    for (uint256 i = 0; i < erc721Balance; ) {
      // Transfer out ERC721 balance
      _withdrawAndStoreERC721(target_);
      unchecked {
        ++i;
      }
    }
  }

  function _getOwnerOf(
    uint256 id_
  ) internal view virtual returns (address ownerOf_) {
    uint256 data = _ownedData[id_];

    assembly {
      ownerOf_ := and(data, _BITMASK_ADDRESS)
    }
  }

  function _setOwnerOf(uint256 id_, address owner_) internal virtual {
    uint256 data = _ownedData[id_];

    assembly {
      data := add(
        and(data, _BITMASK_OWNED_INDEX),
        and(owner_, _BITMASK_ADDRESS)
      )
    }

    _ownedData[id_] = data;
  }

  function _getOwnedIndex(
    uint256 id_
  ) internal view virtual returns (uint256 ownedIndex_) {
    uint256 data = _ownedData[id_];

    assembly {
      ownedIndex_ := shr(160, data)
    }
  }

  function _setOwnedIndex(uint256 id_, uint256 index_) internal virtual {
    uint256 data = _ownedData[id_];

    if (index_ > _BITMASK_OWNED_INDEX >> 160) {
      revert OwnedIndexOverflow();
    }

    assembly {
      data := add(
        and(data, _BITMASK_ADDRESS),
        and(shl(160, index_), _BITMASK_OWNED_INDEX)
      )
    }

    _ownedData[id_] = data;
  }
}
          

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {ERC404} from "../ERC404.sol";
import {IUniswapV2Router02} from "@uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router02.sol";

abstract contract ERC404UniswapV2Exempt is ERC404 {
  constructor(
    address uniswapV2Router_
  ) {
    IUniswapV2Router02 uniswapV2RouterContract = IUniswapV2Router02(uniswapV2Router_);

    // Set the Uniswap v2 router as exempt.
    _setERC721TransferExempt(uniswapV2Router_, true);

    // Determine the Uniswap v2 pair address for this token.
    address uniswapV2Pair = _getUniswapV2Pair(uniswapV2RouterContract.factory(), uniswapV2RouterContract.WETH());

    // Set the Uniswap v2 pair as exempt.
    _setERC721TransferExempt(uniswapV2Pair, true);
  }

  function _getUniswapV2Pair(
    address uniswapV2Factory_,
    address weth_
  ) private view returns (address) {
    address thisAddress = address(this);

    (address token0, address token1) = thisAddress < weth_
      ? (thisAddress, weth_)
      : (weth_, thisAddress);

    return
      address(
        uint160(
          uint256(
            keccak256(
              abi.encodePacked(
                hex"ff",
                uniswapV2Factory_,
                keccak256(abi.encodePacked(token0, token1)),
                hex"96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f"
              )
            )
          )
        )
      );
  }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library AddressUpgradeable {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.8.0/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {
    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the token collection symbol.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/IAccessControl.sol)

pragma solidity ^0.8.0;

/**
 * @dev External interface of AccessControl declared to support ERC165 detection.
 */
interface IAccessControlUpgradeable {
    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);

    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {AccessControl-_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) external view returns (bool);

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {AccessControl-_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) external view returns (bytes32);

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) external;

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) external;

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) external;
}
          

pragma solidity >=0.6.2;

import './IUniswapV2Router01.sol';

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/cryptography/EIP712.sol)

pragma solidity ^0.8.8;

import "./ECDSAUpgradeable.sol";
import "../../interfaces/IERC5267Upgradeable.sol";
import {Initializable} from "../../proxy/utils/Initializable.sol";

/**
 * @dev https://eips.ethereum.org/EIPS/eip-712[EIP 712] is a standard for hashing and signing of typed structured data.
 *
 * The encoding specified in the EIP is very generic, and such a generic implementation in Solidity is not feasible,
 * thus this contract does not implement the encoding itself. Protocols need to implement the type-specific encoding
 * they need in their contracts using a combination of `abi.encode` and `keccak256`.
 *
 * This contract implements the EIP 712 domain separator ({_domainSeparatorV4}) that is used as part of the encoding
 * scheme, and the final step of the encoding to obtain the message digest that is then signed via ECDSA
 * ({_hashTypedDataV4}).
 *
 * The implementation of the domain separator was designed to be as efficient as possible while still properly updating
 * the chain id to protect against replay attacks on an eventual fork of the chain.
 *
 * NOTE: This contract implements the version of the encoding known as "v4", as implemented by the JSON RPC method
 * https://docs.metamask.io/guide/signing-data.html[`eth_signTypedDataV4` in MetaMask].
 *
 * NOTE: In the upgradeable version of this contract, the cached values will correspond to the address, and the domain
 * separator of the implementation contract. This will cause the `_domainSeparatorV4` function to always rebuild the
 * separator from the immutable values, which is cheaper than accessing a cached version in cold storage.
 *
 * _Available since v3.4._
 *
 * @custom:storage-size 52
 */
abstract contract EIP712Upgradeable is Initializable, IERC5267Upgradeable {
    bytes32 private constant _TYPE_HASH =
        keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)");

    /// @custom:oz-renamed-from _HASHED_NAME
    bytes32 private _hashedName;
    /// @custom:oz-renamed-from _HASHED_VERSION
    bytes32 private _hashedVersion;

    string private _name;
    string private _version;

    /**
     * @dev Initializes the domain separator and parameter caches.
     *
     * The meaning of `name` and `version` is specified in
     * https://eips.ethereum.org/EIPS/eip-712#definition-of-domainseparator[EIP 712]:
     *
     * - `name`: the user readable name of the signing domain, i.e. the name of the DApp or the protocol.
     * - `version`: the current major version of the signing domain.
     *
     * NOTE: These parameters cannot be changed except through a xref:learn::upgrading-smart-contracts.adoc[smart
     * contract upgrade].
     */
    function __EIP712_init(string memory name, string memory version) internal onlyInitializing {
        __EIP712_init_unchained(name, version);
    }

    function __EIP712_init_unchained(string memory name, string memory version) internal onlyInitializing {
        _name = name;
        _version = version;

        // Reset prior values in storage if upgrading
        _hashedName = 0;
        _hashedVersion = 0;
    }

    /**
     * @dev Returns the domain separator for the current chain.
     */
    function _domainSeparatorV4() internal view returns (bytes32) {
        return _buildDomainSeparator();
    }

    function _buildDomainSeparator() private view returns (bytes32) {
        return keccak256(abi.encode(_TYPE_HASH, _EIP712NameHash(), _EIP712VersionHash(), block.chainid, address(this)));
    }

    /**
     * @dev Given an already https://eips.ethereum.org/EIPS/eip-712#definition-of-hashstruct[hashed struct], this
     * function returns the hash of the fully encoded EIP712 message for this domain.
     *
     * This hash can be used together with {ECDSA-recover} to obtain the signer of a message. For example:
     *
     * ```solidity
     * bytes32 digest = _hashTypedDataV4(keccak256(abi.encode(
     *     keccak256("Mail(address to,string contents)"),
     *     mailTo,
     *     keccak256(bytes(mailContents))
     * )));
     * address signer = ECDSA.recover(digest, signature);
     * ```
     */
    function _hashTypedDataV4(bytes32 structHash) internal view virtual returns (bytes32) {
        return ECDSAUpgradeable.toTypedDataHash(_domainSeparatorV4(), structHash);
    }

    /**
     * @dev See {EIP-5267}.
     *
     * _Available since v4.9._
     */
    function eip712Domain()
        public
        view
        virtual
        override
        returns (
            bytes1 fields,
            string memory name,
            string memory version,
            uint256 chainId,
            address verifyingContract,
            bytes32 salt,
            uint256[] memory extensions
        )
    {
        // If the hashed name and version in storage are non-zero, the contract hasn't been properly initialized
        // and the EIP712 domain is not reliable, as it will be missing name and version.
        require(_hashedName == 0 && _hashedVersion == 0, "EIP712: Uninitialized");

        return (
            hex"0f", // 01111
            _EIP712Name(),
            _EIP712Version(),
            block.chainid,
            address(this),
            bytes32(0),
            new uint256[](0)
        );
    }

    /**
     * @dev The name parameter for the EIP712 domain.
     *
     * NOTE: This function reads from storage by default, but can be redefined to return a constant value if gas costs
     * are a concern.
     */
    function _EIP712Name() internal virtual view returns (string memory) {
        return _name;
    }

    /**
     * @dev The version parameter for the EIP712 domain.
     *
     * NOTE: This function reads from storage by default, but can be redefined to return a constant value if gas costs
     * are a concern.
     */
    function _EIP712Version() internal virtual view returns (string memory) {
        return _version;
    }

    /**
     * @dev The hash of the name parameter for the EIP712 domain.
     *
     * NOTE: In previous versions this function was virtual. In this version you should override `_EIP712Name` instead.
     */
    function _EIP712NameHash() internal view returns (bytes32) {
        string memory name = _EIP712Name();
        if (bytes(name).length > 0) {
            return keccak256(bytes(name));
        } else {
            // If the name is empty, the contract may have been upgraded without initializing the new storage.
            // We return the name hash in storage if non-zero, otherwise we assume the name is empty by design.
            bytes32 hashedName = _hashedName;
            if (hashedName != 0) {
                return hashedName;
            } else {
                return keccak256("");
            }
        }
    }

    /**
     * @dev The hash of the version parameter for the EIP712 domain.
     *
     * NOTE: In previous versions this function was virtual. In this version you should override `_EIP712Version` instead.
     */
    function _EIP712VersionHash() internal view returns (bytes32) {
        string memory version = _EIP712Version();
        if (bytes(version).length > 0) {
            return keccak256(bytes(version));
        } else {
            // If the version is empty, the contract may have been upgraded without initializing the new storage.
            // We return the version hash in storage if non-zero, otherwise we assume the version is empty by design.
            bytes32 hashedVersion = _hashedVersion;
            if (hashedVersion != 0) {
                return hashedVersion;
            } else {
                return keccak256("");
            }
        }
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[48] private __gap;
}
          

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {MerkleProof} from "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
import {IERC404MerkleClaim} from "./IERC404MerkleClaim.sol";

abstract contract ERC404MerkleClaim is IERC404MerkleClaim {
  bool public airdropIsOpen;
  bytes32 public airdropMerkleRoot;
  mapping(address => bool) public hasClaimedAirdrop;

  modifier whenAirdropIsOpen() {
    if (airdropMerkleRoot == 0 || !airdropIsOpen) {
      revert AirdropIsClosed();
    }
    _;
  }

  function verifyProof(
    bytes32[] memory proof_,
    address claimer_,
    uint256 value_
  ) public view returns (bool) {
    bytes32 leaf = keccak256(
      bytes.concat(keccak256(abi.encode(claimer_, value_)))
    );
    if (MerkleProof.verify(proof_, airdropMerkleRoot, leaf)) {
      return true;
    }
    return false;
  }

  // To use, override this function in your contract, call
  // super.airdropMint(proof_) within your override function, then mint tokens.
  function airdropMint(
    bytes32[] memory proof_,
    uint256 value_
  ) public virtual whenAirdropIsOpen {
    _validateAndRecordAirdropClaim(proof_, msg.sender, value_);
  }

  function _setAirdropMerkleRoot(bytes32 airdropMerkleRoot_) internal {
    airdropMerkleRoot = airdropMerkleRoot_;
  }

  function _toggleAirdropIsOpen() internal {
    airdropIsOpen = !airdropIsOpen;
  }

  function _validateAndRecordAirdropClaim(
    bytes32[] memory proof_,
    address claimer_,
    uint256 value_
  ) internal {
    // Check that the address is eligible.
    if (!verifyProof(proof_, claimer_, value_)) {
      revert NotEligibleForAirdrop();
    }

    // Check if address has already claimed their airdrop.
    if (hasClaimedAirdrop[claimer_]) {
      revert AirdropAlreadyClaimed();
    }

    // Mark address as claimed.
    hasClaimedAirdrop[claimer_] = true;
  }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (proxy/beacon/IBeacon.sol)

pragma solidity ^0.8.0;

/**
 * @dev This is the interface that {BeaconProxy} expects of its beacon.
 */
interface IBeaconUpgradeable {
    /**
     * @dev Must return an address that can be used as a delegate call target.
     *
     * {BeaconProxy} will check that this address is a contract.
     */
    function implementation() external view returns (address);
}
          

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

library ERC721Events {
  event ApprovalForAll(
    address indexed owner,
    address indexed operator,
    bool approved
  );
  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 indexed id
  );
  event Transfer(
    address indexed from,
    address indexed to,
    uint256 indexed id
  );
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.4) (token/ERC20/extensions/ERC20Permit.sol)

pragma solidity ^0.8.0;

import "./IERC20PermitUpgradeable.sol";
import "../ERC20Upgradeable.sol";
import "../../../utils/cryptography/ECDSAUpgradeable.sol";
import "../../../utils/cryptography/EIP712Upgradeable.sol";
import "../../../utils/CountersUpgradeable.sol";
import {Initializable} from "../../../proxy/utils/Initializable.sol";

/**
 * @dev Implementation of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on `{IERC20-approve}`, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 *
 * _Available since v3.4._
 *
 * @custom:storage-size 51
 */
abstract contract ERC20PermitUpgradeable is Initializable, ERC20Upgradeable, IERC20PermitUpgradeable, EIP712Upgradeable {
    using CountersUpgradeable for CountersUpgradeable.Counter;

    mapping(address => CountersUpgradeable.Counter) private _nonces;

    // solhint-disable-next-line var-name-mixedcase
    bytes32 private constant _PERMIT_TYPEHASH =
        keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    /**
     * @dev In previous versions `_PERMIT_TYPEHASH` was declared as `immutable`.
     * However, to ensure consistency with the upgradeable transpiler, we will continue
     * to reserve a slot.
     * @custom:oz-renamed-from _PERMIT_TYPEHASH
     */
    // solhint-disable-next-line var-name-mixedcase
    bytes32 private _PERMIT_TYPEHASH_DEPRECATED_SLOT;

    /**
     * @dev Initializes the {EIP712} domain separator using the `name` parameter, and setting `version` to `"1"`.
     *
     * It's a good idea to use the same `name` that is defined as the ERC20 token name.
     */
    function __ERC20Permit_init(string memory name) internal onlyInitializing {
        __EIP712_init_unchained(name, "1");
    }

    function __ERC20Permit_init_unchained(string memory) internal onlyInitializing {}

    /**
     * @inheritdoc IERC20PermitUpgradeable
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) public virtual override {
        require(block.timestamp <= deadline, "ERC20Permit: expired deadline");

        bytes32 structHash = keccak256(abi.encode(_PERMIT_TYPEHASH, owner, spender, value, _useNonce(owner), deadline));

        bytes32 hash = _hashTypedDataV4(structHash);

        address signer = ECDSAUpgradeable.recover(hash, v, r, s);
        require(signer == owner, "ERC20Permit: invalid signature");

        _approve(owner, spender, value);
    }

    /**
     * @inheritdoc IERC20PermitUpgradeable
     */
    function nonces(address owner) public view virtual override returns (uint256) {
        return _nonces[owner].current();
    }

    /**
     * @inheritdoc IERC20PermitUpgradeable
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view override returns (bytes32) {
        return _domainSeparatorV4();
    }

    /**
     * @dev "Consume a nonce": return the current value and increment.
     *
     * _Available since v4.1._
     */
    function _useNonce(address owner) internal virtual returns (uint256 current) {
        CountersUpgradeable.Counter storage nonce = _nonces[owner];
        current = nonce.current();
        nonce.increment();
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[49] private __gap;
}
          

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {IERC165} from "@openzeppelin/contracts/interfaces/IERC165.sol";

interface IERC404 is IERC165 {
  error NotFound();
  error InvalidTokenId();
  error AlreadyExists();
  error InvalidRecipient();
  error InvalidSender();
  error InvalidSpender();
  error InvalidOperator();
  error UnsafeRecipient();
  error RecipientIsERC721TransferExempt();
  error Unauthorized();
  error InsufficientAllowance();
  error DecimalsTooLow();
  error PermitDeadlineExpired();
  error InvalidSigner();
  error InvalidApproval();
  error OwnedIndexOverflow();
  error MintLimitReached();
  error InvalidExemption();

  function name() external view returns (string memory);
  function symbol() external view returns (string memory);
  function decimals() external view returns (uint8);
  function totalSupply() external view returns (uint256);
  function erc20TotalSupply() external view returns (uint256);
  function erc721TotalSupply() external view returns (uint256);
  function balanceOf(address owner_) external view returns (uint256);
  function erc721BalanceOf(address owner_) external view returns (uint256);
  function erc20BalanceOf(address owner_) external view returns (uint256);
  function erc721TransferExempt(address account_) external view returns (bool);
  function isApprovedForAll(
    address owner_,
    address operator_
  ) external view returns (bool);
  function allowance(
    address owner_,
    address spender_
  ) external view returns (uint256);
  function owned(address owner_) external view returns (uint256[] memory);
  function ownerOf(uint256 id_) external view returns (address erc721Owner);
  function tokenURI(uint256 id_) external view returns (string memory);
  function approve(
    address spender_,
    uint256 valueOrId_
  ) external returns (bool);
  function erc20Approve(
    address spender_,
    uint256 value_
  ) external returns (bool);
  function erc721Approve(address spender_, uint256 id_) external;
  function setApprovalForAll(address operator_, bool approved_) external;
  function transferFrom(
    address from_,
    address to_,
    uint256 valueOrId_
  ) external returns (bool);
  function erc20TransferFrom(
    address from_,
    address to_,
    uint256 value_
  ) external returns (bool);
  function erc721TransferFrom(address from_, address to_, uint256 id_) external;
  function transfer(address to_, uint256 amount_) external returns (bool);
  function getERC721QueueLength() external view returns (uint256);
  function getERC721TokensInQueue(
    uint256 start_,
    uint256 count_
  ) external view returns (uint256[] memory);
  function setSelfERC721TransferExempt(bool state_) external;
  function safeTransferFrom(address from_, address to_, uint256 id_) external;
  function safeTransferFrom(
    address from_,
    address to_,
    uint256 id_,
    bytes calldata data_
  ) external;
  function DOMAIN_SEPARATOR() external view returns (bytes32);
  function permit(
    address owner_,
    address spender_,
    uint256 value_,
    uint256 deadline_,
    uint8 v_,
    bytes32 r_,
    bytes32 s_
  ) external;
}
          

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

abstract contract ERC721Receiver {
  function onERC721Received(
    address,
    address,
    uint256,
    bytes calldata
  ) external virtual returns (bytes4) {
    return ERC721Receiver.onERC721Received.selector;
  }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/StorageSlot.sol)
// This file was procedurally generated from scripts/generate/templates/StorageSlot.js.

pragma solidity ^0.8.0;

/**
 * @dev Library for reading and writing primitive types to specific storage slots.
 *
 * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
 * This library helps with reading and writing to such slots without the need for inline assembly.
 *
 * The functions in this library return Slot structs that contain a `value` member that can be used to read or write.
 *
 * Example usage to set ERC1967 implementation slot:
 * ```solidity
 * contract ERC1967 {
 *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
 *
 *     function _getImplementation() internal view returns (address) {
 *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
 *     }
 *
 *     function _setImplementation(address newImplementation) internal {
 *         require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
 *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
 *     }
 * }
 * ```
 *
 * _Available since v4.1 for `address`, `bool`, `bytes32`, `uint256`._
 * _Available since v4.9 for `string`, `bytes`._
 */
library StorageSlotUpgradeable {
    struct AddressSlot {
        address value;
    }

    struct BooleanSlot {
        bool value;
    }

    struct Bytes32Slot {
        bytes32 value;
    }

    struct Uint256Slot {
        uint256 value;
    }

    struct StringSlot {
        string value;
    }

    struct BytesSlot {
        bytes value;
    }

    /**
     * @dev Returns an `AddressSlot` with member `value` located at `slot`.
     */
    function getAddressSlot(bytes32 slot) internal pure returns (AddressSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `BooleanSlot` with member `value` located at `slot`.
     */
    function getBooleanSlot(bytes32 slot) internal pure returns (BooleanSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `Bytes32Slot` with member `value` located at `slot`.
     */
    function getBytes32Slot(bytes32 slot) internal pure returns (Bytes32Slot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `Uint256Slot` with member `value` located at `slot`.
     */
    function getUint256Slot(bytes32 slot) internal pure returns (Uint256Slot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `StringSlot` with member `value` located at `slot`.
     */
    function getStringSlot(bytes32 slot) internal pure returns (StringSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `StringSlot` representation of the string storage pointer `store`.
     */
    function getStringSlot(string storage store) internal pure returns (StringSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := store.slot
        }
    }

    /**
     * @dev Returns an `BytesSlot` with member `value` located at `slot`.
     */
    function getBytesSlot(bytes32 slot) internal pure returns (BytesSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `BytesSlot` representation of the bytes storage pointer `store`.
     */
    function getBytesSlot(bytes storage store) internal pure returns (BytesSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := store.slot
        }
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (proxy/utils/Initializable.sol)

pragma solidity ^0.8.2;

import "../../utils/AddressUpgradeable.sol";

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
 * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
 * case an upgrade adds a module that needs to be initialized.
 *
 * For example:
 *
 * [.hljs-theme-light.nopadding]
 * ```solidity
 * contract MyToken is ERC20Upgradeable {
 *     function initialize() initializer public {
 *         __ERC20_init("MyToken", "MTK");
 *     }
 * }
 *
 * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
 *     function initializeV2() reinitializer(2) public {
 *         __ERC20Permit_init("MyToken");
 *     }
 * }
 * ```
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 *
 * [CAUTION]
 * ====
 * Avoid leaving a contract uninitialized.
 *
 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
 * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
 * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * /// @custom:oz-upgrades-unsafe-allow constructor
 * constructor() {
 *     _disableInitializers();
 * }
 * ```
 * ====
 */
abstract contract Initializable {
    /**
     * @dev Indicates that the contract has been initialized.
     * @custom:oz-retyped-from bool
     */
    uint8 private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Triggered when the contract has been initialized or reinitialized.
     */
    event Initialized(uint8 version);

    /**
     * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
     * `onlyInitializing` functions can be used to initialize parent contracts.
     *
     * Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
     * constructor.
     *
     * Emits an {Initialized} event.
     */
    modifier initializer() {
        bool isTopLevelCall = !_initializing;
        require(
            (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
            "Initializable: contract is already initialized"
        );
        _initialized = 1;
        if (isTopLevelCall) {
            _initializing = true;
        }
        _;
        if (isTopLevelCall) {
            _initializing = false;
            emit Initialized(1);
        }
    }

    /**
     * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
     * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
     * used to initialize parent contracts.
     *
     * A reinitializer may be used after the original initialization step. This is essential to configure modules that
     * are added through upgrades and that require initialization.
     *
     * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
     * cannot be nested. If one is invoked in the context of another, execution will revert.
     *
     * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
     * a contract, executing them in the right order is up to the developer or operator.
     *
     * WARNING: setting the version to 255 will prevent any future reinitialization.
     *
     * Emits an {Initialized} event.
     */
    modifier reinitializer(uint8 version) {
        require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
        _initialized = version;
        _initializing = true;
        _;
        _initializing = false;
        emit Initialized(version);
    }

    /**
     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
     * {initializer} and {reinitializer} modifiers, directly or indirectly.
     */
    modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
    }

    /**
     * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
     * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
     * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
     * through proxies.
     *
     * Emits an {Initialized} event the first time it is successfully executed.
     */
    function _disableInitializers() internal virtual {
        require(!_initializing, "Initializable: contract is initializing");
        if (_initialized != type(uint8).max) {
            _initialized = type(uint8).max;
            emit Initialized(type(uint8).max);
        }
    }

    /**
     * @dev Returns the highest version that has been initialized. See {reinitializer}.
     */
    function _getInitializedVersion() internal view returns (uint8) {
        return _initialized;
    }

    /**
     * @dev Returns `true` if the contract is currently initializing. See {onlyInitializing}.
     */
    function _isInitializing() internal view returns (bool) {
        return _initializing;
    }
}
          

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {IERC721Receiver} from "@openzeppelin/contracts/interfaces/IERC721Receiver.sol";
import {IERC165} from "@openzeppelin/contracts/interfaces/IERC165.sol";
import {IERC404} from "./interfaces/IERC404.sol";
import {PackedDoubleEndedQueue} from "./lib/PackedDoubleEndedQueue.sol";
import {ERC721Events} from "./lib/ERC721Events.sol";
import {ERC20Events} from "./lib/ERC20Events.sol";

/// @dev This is an optimized ERC404 implementation designed to support smaller collections,
///      with id's up to a maximum of 65535.
abstract contract ERC404U16 is IERC404 {
  using PackedDoubleEndedQueue for PackedDoubleEndedQueue.Uint16Deque;

  /// @dev The queue of ERC-721 tokens stored in the contract.
  PackedDoubleEndedQueue.Uint16Deque private _storedERC721Ids;

  /// @dev Token name
  string public name;

  /// @dev Token symbol
  string public symbol;

  /// @dev Decimals for ERC-20 representation
  uint8 public immutable decimals;

  /// @dev Units for ERC-20 representation
  uint256 public immutable units;

  /// @dev Total supply in ERC-20 representation
  uint256 public totalSupply;

  /// @dev Current mint counter which also represents the highest
  ///      minted id, monotonically increasing to ensure accurate ownership
  uint256 public minted;

  /// @dev Initial chain id for EIP-2612 support
  uint256 internal immutable _INITIAL_CHAIN_ID;

  /// @dev Initial domain separator for EIP-2612 support
  bytes32 internal immutable _INITIAL_DOMAIN_SEPARATOR;

  /// @dev Balance of user in ERC-20 representation
  mapping(address => uint256) public balanceOf;

  /// @dev Allowance of user in ERC-20 representation
  mapping(address => mapping(address => uint256)) public allowance;

  /// @dev Approval in ERC-721 representaion
  mapping(uint256 => address) public getApproved;

  /// @dev Approval for all in ERC-721 representation
  mapping(address => mapping(address => bool)) public isApprovedForAll;

  /// @dev Packed representation of ownerOf and owned indices
  mapping(uint256 => uint256) internal _ownedData;

  /// @dev Array of owned ids in ERC-721 representation
  mapping(address => uint16[]) internal _owned;

  /// @dev Addresses that are exempt from ERC-721 transfer, typically for gas savings (pairs, routers, etc)
  mapping(address => bool) internal _erc721TransferExempt;

  /// @dev EIP-2612 nonces
  mapping(address => uint256) public nonces;

  /// @dev Address bitmask for packed ownership data
  uint256 private constant _BITMASK_ADDRESS = (1 << 160) - 1;

  /// @dev Owned index bitmask for packed ownership data
  uint256 private constant _BITMASK_OWNED_INDEX = ((1 << 96) - 1) << 160;

  /// @dev Constant for token id encoding
  uint256 public constant ID_ENCODING_PREFIX = 1 << 255;

  constructor(string memory name_, string memory symbol_, uint8 decimals_) {
    name = name_;
    symbol = symbol_;

    if (decimals_ < 18) {
      revert DecimalsTooLow();
    }

    decimals = decimals_;
    units = 10 ** decimals;

    // EIP-2612 initialization
    _INITIAL_CHAIN_ID = block.chainid;
    _INITIAL_DOMAIN_SEPARATOR = _computeDomainSeparator();
  }

  /// @notice Function to find owner of a given ERC-721 token
  function ownerOf(
    uint256 id_
  ) public view virtual returns (address erc721Owner) {
    erc721Owner = _getOwnerOf(id_);

    // If the id_ is beyond the range of minted tokens, is 0, or the token is not owned by anyone, revert.
    if (id_ <= ID_ENCODING_PREFIX || erc721Owner == address(0)) {
      revert NotFound();
    }
  }

  function owned(
    address owner_
  ) public view virtual returns (uint256[] memory) {
    uint256[] memory ownedAsU256 = new uint256[](_owned[owner_].length);

    for (uint256 i = 0; i < _owned[owner_].length; ) {
      ownedAsU256[i] = ID_ENCODING_PREFIX + _owned[owner_][i];

      unchecked {
        ++i;
      }
    }

    return ownedAsU256;
  }

  function erc721BalanceOf(
    address owner_
  ) public view virtual returns (uint256) {
    return _owned[owner_].length;
  }

  function erc20BalanceOf(
    address owner_
  ) public view virtual returns (uint256) {
    return balanceOf[owner_];
  }

  function erc20TotalSupply() public view virtual returns (uint256) {
    return totalSupply;
  }

  function erc721TotalSupply() public view virtual returns (uint256) {
    return minted;
  }

  function getERC721QueueLength() public view virtual returns (uint256) {
    return _storedERC721Ids.length();
  }

  function getERC721TokensInQueue(
    uint256 start_,
    uint256 count_
  ) public view virtual returns (uint256[] memory) {
    uint256[] memory tokensInQueue = new uint256[](count_);

    for (uint256 i = start_; i < start_ + count_; ) {
      tokensInQueue[i - start_] = ID_ENCODING_PREFIX + _storedERC721Ids.at(i);

      unchecked {
        ++i;
      }
    }

    return tokensInQueue;
  }

  /// @notice tokenURI must be implemented by child contract
  function tokenURI(uint256 id_) public view virtual returns (string memory);

  /// @notice Function for token approvals
  /// @dev This function assumes the operator is attempting to approve an ERC-721
  ///      if valueOrId is less than the minted count. Unlike setApprovalForAll,
  ///      spender_ must be allowed to be 0x0 so that approval can be revoked.
  function approve(
    address spender_,
    uint256 valueOrId_
  ) public virtual returns (bool) {
    // The ERC-721 tokens are 1-indexed, so 0 is not a valid id and indicates that
    // operator is attempting to set the ERC-20 allowance to 0.
    if (valueOrId_ > ID_ENCODING_PREFIX && valueOrId_ != type(uint256).max) {
      erc721Approve(spender_, valueOrId_);
    } else {
      return erc20Approve(spender_, valueOrId_);
    }

    return true;
  }

  function erc721Approve(address spender_, uint256 id_) public virtual {
    // Intention is to approve as ERC-721 token (id).
    address erc721Owner = _getOwnerOf(id_);

    if (
      msg.sender != erc721Owner && !isApprovedForAll[erc721Owner][msg.sender]
    ) {
      revert Unauthorized();
    }

    getApproved[id_] = spender_;

    emit ERC721Events.Approval(erc721Owner, spender_, id_);
  }

  /// @dev Providing type(uint256).max for approval value results in an
  ///      unlimited approval that is not deducted from on transfers.
  function erc20Approve(
    address spender_,
    uint256 value_
  ) public virtual returns (bool) {
    // Prevent granting 0x0 an ERC-20 allowance.
    if (spender_ == address(0)) {
      revert InvalidSpender();
    }

    // Intention is to approve as ERC-20 token (value).
    allowance[msg.sender][spender_] = value_;

    emit ERC20Events.Approval(msg.sender, spender_, value_);

    return true;
  }

  /// @notice Function for ERC-721 approvals
  function setApprovalForAll(address operator_, bool approved_) public virtual {
    // Prevent approvals to 0x0.
    if (operator_ == address(0)) {
      revert InvalidOperator();
    }
    isApprovedForAll[msg.sender][operator_] = approved_;
    emit ERC721Events.ApprovalForAll(msg.sender, operator_, approved_);
  }

  /// @notice Function for mixed transfers from an operator that may be different than 'from'.
  /// @dev This function assumes the operator is attempting to transfer an ERC-721
  ///      if valueOrId is less than or equal to current max id.
  function transferFrom(
    address from_,
    address to_,
    uint256 valueOrId_
  ) public virtual returns (bool) {
    if (valueOrId_ > ID_ENCODING_PREFIX) {
      erc721TransferFrom(from_, to_, valueOrId_);
    } else {
      // Intention is to transfer as ERC-20 token (value).
      return erc20TransferFrom(from_, to_, valueOrId_);
    }

    return true;
  }

  /// @notice Function for ERC-721 transfers from.
  /// @dev This function is recommended for ERC721 transfers
  function erc721TransferFrom(
    address from_,
    address to_,
    uint256 id_
  ) public virtual {
    // Prevent transferring tokens from 0x0.
    if (from_ == address(0)) {
      revert InvalidSender();
    }

    // Prevent burning tokens to 0x0.
    if (to_ == address(0)) {
      revert InvalidRecipient();
    }

    if (from_ != _getOwnerOf(id_)) {
      revert Unauthorized();
    }

    // Check that the operator is either the sender or approved for the transfer.
    if (
      msg.sender != from_ &&
      !isApprovedForAll[from_][msg.sender] &&
      msg.sender != getApproved[id_]
    ) {
      revert Unauthorized();
    }

    if (erc721TransferExempt(to_)) {
      revert RecipientIsERC721TransferExempt();
    }

    // Transfer 1 * units ERC-20 and 1 ERC-721 token.
    // ERC-721 transfer exemptions handled above. Can't make it to this point if either is transfer exempt.
    _transferERC20(from_, to_, units);
    _transferERC721(from_, to_, id_);
  }

  /// @notice Function for ERC-20 transfers from.
  /// @dev This function is recommended for ERC20 transfers
  function erc20TransferFrom(
    address from_,
    address to_,
    uint256 value_
  ) public virtual returns (bool) {
    // Prevent transferring tokens from 0x0.
    if (from_ == address(0)) {
      revert InvalidSender();
    }

    // Prevent burning tokens to 0x0.
    if (to_ == address(0)) {
      revert InvalidRecipient();
    }

    // Intention is to transfer as ERC-20 token (value).
    uint256 allowed = allowance[from_][msg.sender];

    // Check that the operator has sufficient allowance.
    if (allowed != type(uint256).max) {
      allowance[from_][msg.sender] = allowed - value_;
    }

    // Transferring ERC-20s directly requires the _transfer function.
    // Handles ERC-721 exemptions internally.
    return _transferERC20WithERC721(from_, to_, value_);
  }

  /// @notice Function for ERC-20 transfers.
  /// @dev This function assumes the operator is attempting to transfer as ERC-20
  ///      given this function is only supported on the ERC-20 interface.
  ///      Treats even small amounts that are valid ERC-721 ids as ERC-20s.
  function transfer(address to_, uint256 value_) public virtual returns (bool) {
    // Prevent burning tokens to 0x0.
    if (to_ == address(0)) {
      revert InvalidRecipient();
    }

    // Transferring ERC-20s directly requires the _transfer function.
    // Handles ERC-721 exemptions internally.
    return _transferERC20WithERC721(msg.sender, to_, value_);
  }

  /// @notice Function for ERC-721 transfers with contract support.
  /// This function only supports moving valid ERC-721 ids, as it does not exist on the ERC-20
  /// spec and will revert otherwise.
  function safeTransferFrom(
    address from_,
    address to_,
    uint256 id_
  ) public virtual {
    safeTransferFrom(from_, to_, id_, "");
  }

  /// @notice Function for ERC-721 transfers with contract support and callback data.
  /// This function only supports moving valid ERC-721 ids, as it does not exist on the
  /// ERC-20 spec and will revert otherwise.
  function safeTransferFrom(
    address from_,
    address to_,
    uint256 id_,
    bytes memory data_
  ) public virtual {
    if (id_ <= ID_ENCODING_PREFIX) {
      revert InvalidTokenId();
    }

    transferFrom(from_, to_, id_);

    if (
      to_.code.length != 0 &&
      IERC721Receiver(to_).onERC721Received(msg.sender, from_, id_, data_) !=
      IERC721Receiver.onERC721Received.selector
    ) {
      revert UnsafeRecipient();
    }
  }

  /// @notice Function for EIP-2612 permits
  /// @dev Providing type(uint256).max for permit value results in an
  ///      unlimited approval that is not deducted from on transfers.
  function permit(
    address owner_,
    address spender_,
    uint256 value_,
    uint256 deadline_,
    uint8 v_,
    bytes32 r_,
    bytes32 s_
  ) public virtual {
    if (deadline_ < block.timestamp) {
      revert PermitDeadlineExpired();
    }

    if (value_ > ID_ENCODING_PREFIX && value_ != type(uint256).max) {
      revert InvalidApproval();
    }

    if (spender_ == address(0)) {
      revert InvalidSpender();
    }

    unchecked {
      address recoveredAddress = ecrecover(
        keccak256(
          abi.encodePacked(
            "\x19\x01",
            DOMAIN_SEPARATOR(),
            keccak256(
              abi.encode(
                keccak256(
                  "Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)"
                ),
                owner_,
                spender_,
                value_,
                nonces[owner_]++,
                deadline_
              )
            )
          )
        ),
        v_,
        r_,
        s_
      );

      if (recoveredAddress == address(0) || recoveredAddress != owner_) {
        revert InvalidSigner();
      }

      allowance[recoveredAddress][spender_] = value_;
    }

    emit ERC20Events.Approval(owner_, spender_, value_);
  }

  /// @notice Returns domain initial domain separator, or recomputes if chain id is not equal to initial chain id
  function DOMAIN_SEPARATOR() public view virtual returns (bytes32) {
    return
      block.chainid == _INITIAL_CHAIN_ID
        ? _INITIAL_DOMAIN_SEPARATOR
        : _computeDomainSeparator();
  }

  function supportsInterface(
    bytes4 interfaceId
  ) public view virtual returns (bool) {
    return
      interfaceId == type(IERC404).interfaceId ||
      interfaceId == type(IERC165).interfaceId;
  }

  /// @notice Function for self-exemption
  function setSelfERC721TransferExempt(bool state_) public virtual {
    _setERC721TransferExempt(msg.sender, state_);
  }

  /// @notice Function to check if address is transfer exempt
  function erc721TransferExempt(
    address target_
  ) public view virtual returns (bool) {
    return target_ == address(0) || _erc721TransferExempt[target_];
  }

  /// @notice Internal function to compute domain separator for EIP-2612 permits
  function _computeDomainSeparator() internal view virtual returns (bytes32) {
    return
      keccak256(
        abi.encode(
          keccak256(
            "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"
          ),
          keccak256(bytes(name)),
          keccak256("1"),
          block.chainid,
          address(this)
        )
      );
  }

  /// @notice This is the lowest level ERC-20 transfer function, which
  ///         should be used for both normal ERC-20 transfers as well as minting.
  /// Note that this function allows transfers to and from 0x0.
  function _transferERC20(
    address from_,
    address to_,
    uint256 value_
  ) internal virtual {
    // Minting is a special case for which we should not check the balance of
    // the sender, and we should increase the total supply.
    if (from_ == address(0)) {
      totalSupply += value_;
    } else {
      // Deduct value from sender's balance.
      balanceOf[from_] -= value_;
    }

    // Update the recipient's balance.
    // Can be unchecked because on mint, adding to totalSupply is checked, and on transfer balance deduction is checked.
    unchecked {
      balanceOf[to_] += value_;
    }

    emit ERC20Events.Transfer(from_, to_, value_);
  }

  /// @notice Consolidated record keeping function for transferring ERC-721s.
  /// @dev Assign the token to the new owner, and remove from the old owner.
  /// Note that this function allows transfers to and from 0x0.
  /// Does not handle ERC-721 exemptions.
  function _transferERC721(
    address from_,
    address to_,
    uint256 id_
  ) internal virtual {
    // If this is not a mint, handle record keeping for transfer from previous owner.
    if (from_ != address(0)) {
      // On transfer of an NFT, any previous approval is reset.
      delete getApproved[id_];

      uint256 updatedId = ID_ENCODING_PREFIX +
        _owned[from_][_owned[from_].length - 1];
      if (updatedId != id_) {
        uint256 updatedIndex = _getOwnedIndex(id_);
        // update _owned for sender
        _owned[from_][updatedIndex] = uint16(updatedId);
        // update index for the moved id
        _setOwnedIndex(updatedId, updatedIndex);
      }

      // pop
      _owned[from_].pop();
    }

    // Check if this is a burn.
    if (to_ != address(0)) {
      // If not a burn, update the owner of the token to the new owner.
      // Update owner of the token to the new owner.
      _setOwnerOf(id_, to_);
      // Push token onto the new owner's stack.
      _owned[to_].push(uint16(id_));
      // Update index for new owner's stack.
      _setOwnedIndex(id_, _owned[to_].length - 1);
    } else {
      // If this is a burn, reset the owner of the token to 0x0 by deleting the token from _ownedData.
      delete _ownedData[id_];
    }

    emit ERC721Events.Transfer(from_, to_, id_);
  }

  /// @notice Internal function for ERC-20 transfers. Also handles any ERC-721 transfers that may be required.
  // Handles ERC-721 exemptions.
  function _transferERC20WithERC721(
    address from_,
    address to_,
    uint256 value_
  ) internal virtual returns (bool) {
    uint256 erc20BalanceOfSenderBefore = erc20BalanceOf(from_);
    uint256 erc20BalanceOfReceiverBefore = erc20BalanceOf(to_);

    _transferERC20(from_, to_, value_);

    // Preload for gas savings on branches
    bool isFromERC721TransferExempt = erc721TransferExempt(from_);
    bool isToERC721TransferExempt = erc721TransferExempt(to_);

    // Skip _withdrawAndStoreERC721 and/or _retrieveOrMintERC721 for ERC-721 transfer exempt addresses
    // 1) to save gas
    // 2) because ERC-721 transfer exempt addresses won't always have/need ERC-721s corresponding to their ERC20s.
    if (isFromERC721TransferExempt && isToERC721TransferExempt) {
      // Case 1) Both sender and recipient are ERC-721 transfer exempt. No ERC-721s need to be transferred.
      // NOOP.
    } else if (isFromERC721TransferExempt) {
      // Case 2) The sender is ERC-721 transfer exempt, but the recipient is not. Contract should not attempt
      //         to transfer ERC-721s from the sender, but the recipient should receive ERC-721s
      //         from the bank/minted for any whole number increase in their balance.
      // Only cares about whole number increments.
      uint256 tokensToRetrieveOrMint = (balanceOf[to_] / units) -
        (erc20BalanceOfReceiverBefore / units);
      for (uint256 i = 0; i < tokensToRetrieveOrMint; ) {
        _retrieveOrMintERC721(to_);
        unchecked {
          ++i;
        }
      }
    } else if (isToERC721TransferExempt) {
      // Case 3) The sender is not ERC-721 transfer exempt, but the recipient is. Contract should attempt
      //         to withdraw and store ERC-721s from the sender, but the recipient should not
      //         receive ERC-721s from the bank/minted.
      // Only cares about whole number increments.
      uint256 tokensToWithdrawAndStore = (erc20BalanceOfSenderBefore / units) -
        (balanceOf[from_] / units);
      for (uint256 i = 0; i < tokensToWithdrawAndStore; ) {
        _withdrawAndStoreERC721(from_);
        unchecked {
          ++i;
        }
      }
    } else {
      // Case 4) Neither the sender nor the recipient are ERC-721 transfer exempt.
      // Strategy:
      // 1. First deal with the whole tokens. These are easy and will just be transferred.
      // 2. Look at the fractional part of the value:
      //   a) If it causes the sender to lose a whole token that was represented by an NFT due to a
      //      fractional part being transferred, withdraw and store an additional NFT from the sender.
      //   b) If it causes the receiver to gain a whole new token that should be represented by an NFT
      //      due to receiving a fractional part that completes a whole token, retrieve or mint an NFT to the recevier.

      // Whole tokens worth of ERC-20s get transferred as ERC-721s without any burning/minting.
      uint256 nftsToTransfer = value_ / units;
      for (uint256 i = 0; i < nftsToTransfer; ) {
        // Pop from sender's ERC-721 stack and transfer them (LIFO)
        uint256 indexOfLastToken = _owned[from_].length - 1;
        uint256 tokenId = ID_ENCODING_PREFIX + _owned[from_][indexOfLastToken];
        _transferERC721(from_, to_, tokenId);
        unchecked {
          ++i;
        }
      }

      // If the sender's transaction changes their holding from a fractional to a non-fractional
      // amount (or vice versa), adjust ERC-721s.
      //
      // Check if the send causes the sender to lose a whole token that was represented by an ERC-721
      // due to a fractional part being transferred.
      if (
        erc20BalanceOfSenderBefore / units - erc20BalanceOf(from_) / units >
        nftsToTransfer
      ) {
        _withdrawAndStoreERC721(from_);
      }

      if (
        erc20BalanceOf(to_) / units - erc20BalanceOfReceiverBefore / units >
        nftsToTransfer
      ) {
        _retrieveOrMintERC721(to_);
      }
    }

    return true;
  }

  /// @notice Internal function for ERC20 minting
  /// @dev This function will allow minting of new ERC20s.
  ///      If mintCorrespondingERC721s_ is true, and the recipient is not ERC-721 exempt, it will
  ///      also mint the corresponding ERC721s.
  /// Handles ERC-721 exemptions.
  function _mintERC20(address to_, uint256 value_) internal virtual {
    /// You cannot mint to the zero address (you can't mint and immediately burn in the same transfer).
    if (to_ == address(0)) {
      revert InvalidRecipient();
    }

    if (totalSupply + value_ > ID_ENCODING_PREFIX) {
      revert MintLimitReached();
    }

    _transferERC20WithERC721(address(0), to_, value_);
  }

  /// @notice Internal function for ERC-721 minting and retrieval from the bank.
  /// @dev This function will allow minting of new ERC-721s up to the total fractional supply. It will
  ///      first try to pull from the bank, and if the bank is empty, it will mint a new token.
  /// Does not handle ERC-721 exemptions.
  function _retrieveOrMintERC721(address to_) internal virtual {
    if (to_ == address(0)) {
      revert InvalidRecipient();
    }

    uint256 id;

    if (!_storedERC721Ids.empty()) {
      // If there are any tokens in the bank, use those first.
      // Pop off the end of the queue (FIFO).
      id = ID_ENCODING_PREFIX + _storedERC721Ids.popBack();
    } else {
      // Otherwise, mint a new token, should not be able to go over the total fractional supply.
      ++minted;

      // Reserve max uint256 for approvals
      if (minted == type(uint256).max) {
        revert MintLimitReached();
      }

      id = ID_ENCODING_PREFIX + minted;
    }

    address erc721Owner = _getOwnerOf(id);

    // The token should not already belong to anyone besides 0x0 or this contract.
    // If it does, something is wrong, as this should never happen.
    if (erc721Owner != address(0)) {
      revert AlreadyExists();
    }

    // Transfer the token to the recipient, either transferring from the contract's bank or minting.
    // Does not handle ERC-721 exemptions.
    _transferERC721(erc721Owner, to_, id);
  }

  /// @notice Internal function for ERC-721 deposits to bank (this contract).
  /// @dev This function will allow depositing of ERC-721s to the bank, which can be retrieved by future minters.
  // Does not handle ERC-721 exemptions.
  function _withdrawAndStoreERC721(address from_) internal virtual {
    if (from_ == address(0)) {
      revert InvalidSender();
    }

    // Retrieve the latest token added to the owner's stack (LIFO).
    uint256 id = ID_ENCODING_PREFIX + _owned[from_][_owned[from_].length - 1];

    // Transfer to 0x0.
    // Does not handle ERC-721 exemptions.
    _transferERC721(from_, address(0), id);

    // Record the token in the contract's bank queue.
    _storedERC721Ids.pushFront(uint16(id));
  }

  /// @notice Initialization function to set pairs / etc, saving gas by avoiding mint / burn on unnecessary targets
  function _setERC721TransferExempt(
    address target_,
    bool state_
  ) internal virtual {
    if (target_ == address(0)) {
      revert InvalidExemption();
    }

    // Adjust the ERC721 balances of the target to respect exemption rules.
    // Despite this logic, it is still recommended practice to exempt prior to the target
    // having an active balance.
    if (state_) {
      _clearERC721Balance(target_);
    } else {
      _reinstateERC721Balance(target_);
    }

    _erc721TransferExempt[target_] = state_;
  }

  /// @notice Function to reinstate balance on exemption removal
  function _reinstateERC721Balance(address target_) private {
    uint256 expectedERC721Balance = erc20BalanceOf(target_) / units;
    uint256 actualERC721Balance = erc721BalanceOf(target_);

    for (uint256 i = 0; i < expectedERC721Balance - actualERC721Balance; ) {
      // Transfer ERC721 balance in from pool
      _retrieveOrMintERC721(target_);
      unchecked {
        ++i;
      }
    }
  }

  /// @notice Function to clear balance on exemption inclusion
  function _clearERC721Balance(address target_) private {
    uint256 erc721Balance = erc721BalanceOf(target_);

    for (uint256 i = 0; i < erc721Balance; ) {
      // Transfer out ERC721 balance
      _withdrawAndStoreERC721(target_);
      unchecked {
        ++i;
      }
    }
  }

  function _getOwnerOf(
    uint256 id_
  ) internal view virtual returns (address ownerOf_) {
    uint256 data = _ownedData[id_];

    assembly {
      ownerOf_ := and(data, _BITMASK_ADDRESS)
    }
  }

  function _setOwnerOf(uint256 id_, address owner_) internal virtual {
    uint256 data = _ownedData[id_];

    assembly {
      data := add(
        and(data, _BITMASK_OWNED_INDEX),
        and(owner_, _BITMASK_ADDRESS)
      )
    }

    _ownedData[id_] = data;
  }

  function _getOwnedIndex(
    uint256 id_
  ) internal view virtual returns (uint256 ownedIndex_) {
    uint256 data = _ownedData[id_];

    assembly {
      ownedIndex_ := shr(160, data)
    }
  }

  function _setOwnedIndex(uint256 id_, uint256 index_) internal virtual {
    uint256 data = _ownedData[id_];

    if (index_ > _BITMASK_OWNED_INDEX >> 160) {
      revert OwnedIndexOverflow();
    }

    assembly {
      data := add(
        and(data, _BITMASK_ADDRESS),
        and(shl(160, index_), _BITMASK_OWNED_INDEX)
      )
    }

    _ownedData[id_] = data;
  }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external;

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC721
     * or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
     * understand this adds an external call which potentially creates a reentrancy vulnerability.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool approved) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Strings.sol)

pragma solidity ^0.8.0;

import "./math/MathUpgradeable.sol";
import "./math/SignedMathUpgradeable.sol";

/**
 * @dev String operations.
 */
library StringsUpgradeable {
    bytes16 private constant _SYMBOLS = "0123456789abcdef";
    uint8 private constant _ADDRESS_LENGTH = 20;

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        unchecked {
            uint256 length = MathUpgradeable.log10(value) + 1;
            string memory buffer = new string(length);
            uint256 ptr;
            /// @solidity memory-safe-assembly
            assembly {
                ptr := add(buffer, add(32, length))
            }
            while (true) {
                ptr--;
                /// @solidity memory-safe-assembly
                assembly {
                    mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
                }
                value /= 10;
                if (value == 0) break;
            }
            return buffer;
        }
    }

    /**
     * @dev Converts a `int256` to its ASCII `string` decimal representation.
     */
    function toString(int256 value) internal pure returns (string memory) {
        return string(abi.encodePacked(value < 0 ? "-" : "", toString(SignedMathUpgradeable.abs(value))));
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        unchecked {
            return toHexString(value, MathUpgradeable.log256(value) + 1);
        }
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }

    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
    }

    /**
     * @dev Returns true if the two strings are equal.
     */
    function equal(string memory a, string memory b) internal pure returns (bool) {
        return keccak256(bytes(a)) == keccak256(bytes(b));
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/extensions/ERC20Burnable.sol)

pragma solidity ^0.8.0;

import "../ERC20Upgradeable.sol";
import "../../../utils/ContextUpgradeable.sol";
import {Initializable} from "../../../proxy/utils/Initializable.sol";

/**
 * @dev Extension of {ERC20} that allows token holders to destroy both their own
 * tokens and those that they have an allowance for, in a way that can be
 * recognized off-chain (via event analysis).
 */
abstract contract ERC20BurnableUpgradeable is Initializable, ContextUpgradeable, ERC20Upgradeable {
    function __ERC20Burnable_init() internal onlyInitializing {
    }

    function __ERC20Burnable_init_unchained() internal onlyInitializing {
    }
    /**
     * @dev Destroys `amount` tokens from the caller.
     *
     * See {ERC20-_burn}.
     */
    function burn(uint256 amount) public virtual {
        _burn(_msgSender(), amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, deducting from the caller's
     * allowance.
     *
     * See {ERC20-_burn} and {ERC20-allowance}.
     *
     * Requirements:
     *
     * - the caller must have allowance for ``accounts``'s tokens of at least
     * `amount`.
     */
    function burnFrom(address account, uint256 amount) public virtual {
        _spendAllowance(account, _msgSender(), amount);
        _burn(account, amount);
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC20Upgradeable.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20MetadataUpgradeable is IERC20Upgradeable {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}
          

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {IERC721Receiver} from "@openzeppelin/contracts/interfaces/IERC721Receiver.sol";
import {IERC165} from "@openzeppelin/contracts/interfaces/IERC165.sol";
import {IERC721} from "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {IERC721Metadata} from "@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol";
import {IWFFTokenERC404} from "./interfaces/IWFFTokenERC404.sol";
import {DoubleEndedQueue} from "./lib/DoubleEndedQueue.sol";
import {ERC721Events} from "./lib/ERC721Events.sol";
import {ERC20Events} from "./lib/ERC20Events.sol";
import {WFFToken} from "./WFFToken.sol";

abstract contract InheritERC404 is WFFToken, IWFFTokenERC404 {
    using DoubleEndedQueue for DoubleEndedQueue.Uint256Deque;

    // @dev The queue of ERC-721 tokens stored in the contract.
    DoubleEndedQueue.Uint256Deque private _storedERC721Ids;

    // @dev Units for ERC-721 representation
    uint256 public units;

    // @dev Current mint counter which also represents the highest
    //      minted id, monotonically increasing to ensure accurate ownership
    uint256 public minted;

    // @dev Approval in ERC-721 representaion
    mapping(uint256 => address) public getApproved;

    // @dev Approval for all in ERC-721 representation
    mapping(address => mapping(address => bool)) public isApprovedForAll;

    // @dev Packed representation of ownerOf and owned indices
    mapping(uint256 => OwnedData) internal _ownedData;

    // @dev Array of owned ids in ERC-721 representation
    mapping(address => uint256[]) internal _owned;

    // @dev Constant for token id encoding
    uint256 public constant ID_ENCODING_PREFIX = 1 << 255;

    // @dev tokenURI for 721Metadata
    string public baseTokenURI;

    uint256 internal _MAX_TOKEN_ID;

    // @dev Ether to cost to mint for 1 unit ERC-721
    uint256 public mintingCost;

    // @dev Address to keep minting cost for ERC-721
    address public treasury;

    // @dev Packed representation of ownerOf and owned indices
    struct OwnedData {
        address ownerOf;
        uint96 ownedIndex;
    }

    /************************************
    /******** 404 functions *************
    *************************************/
    function erc721Approve(address spender_, uint256 id_) public virtual {
        // Intention is to approve as ERC-721 token (id).
        address erc721Owner = _getOwnerOf(id_);

        if (
            msg.sender != erc721Owner && !isApprovedForAll[erc721Owner][msg.sender]
        ) {
            revert Unauthorized();
        }

        getApproved[id_] = spender_;

        emit ERC721Events.Approval(erc721Owner, spender_, id_);
    }

    /** 
     * @dev Providing type(uint256).max for approval value results in an
     *       unlimited approval that is not deducted from on transfers.
     */
    function erc20Approve(
        address spender_,
        uint256 value_
    ) public virtual returns (bool) {

        // Check spender address == address(0) inside _approve().
        _approve(msg.sender, spender_, value_);

        return true;
    }

    /** 
     * @notice Function for ERC-721 transfers from.
     *  @dev This function is recommended for ERC721 transfers.
     */
    function erc721TransferFrom(
        address from_,
        address to_,
        uint256 id_
    ) public virtual {
        // Prevent minting tokens from 0x0.
        if (from_ == address(0)) {
            revert ERC721InvalidSender(address(0));
        }

        // Prevent burning tokens to 0x0.
        if (to_ == address(0)) {
            revert ERC721InvalidReceiver(address(0));
        }

        if (from_ != _getOwnerOf(id_)) {
            revert Unauthorized();
        }

        // Check that the operator is either the sender or approved for the transfer.
        if (
            msg.sender != from_ &&
            !isApprovedForAll[from_][msg.sender] &&
            msg.sender != getApproved[id_]
        ) {
            revert Unauthorized();
        }

        // Transfer 1 * units ERC-20 and 1 ERC-721 token.
        // ERC-721 transfer exemptions handled above. Can't make it to this point if either is transfer exempt.
        _transferERC721WithERC20(from_, to_, id_);
        // Add ERC-20 event tomake sure transfer event amount is tally with user balance
        emit ERC20Events.Transfer(from_, to_, units);
    }

    /**
     * @notice Function for ERC-20 transfers from.
     * @dev This function is recommended for ERC20 transfers
     */
    function erc20TransferFrom(
        address from_,
        address to_,
        uint256 value_
    ) public virtual returns (bool) {
        // Prevent minting tokens from 0x0.
        if (from_ == address(0)) {
            revert ERC20InvalidSender(address(0));
        }

        // Prevent burning tokens to 0x0.
        if (to_ == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }

        _spendAllowance(from_, msg.sender, value_);

        // Transferring ERC-20s directly requires the _transferERC20 function.
        // Handles ERC-721 exemptions internally.
        return _transferERC20(from_, to_, value_);
    }

    /** 
     * @notice Function to mint ERC-721, 
     * @dev To be able to mint 1 unit of ERC-721, it will need 1,000,000 PURSE token inactive balance available in the address.
     * It will cost Ether when mint ERC-721, exact cost to mint 1-ERC721, please refer to "mintingCost" in Wei
     */
    function mintERC721(uint256 mintUnit_) public virtual payable {
        if(msg.value != mintingCost * mintUnit_) {
            revert IncorrectEthValue();
        }

        address to_ = _msgSender();

        if(inactiveBalance(to_) < mintUnit_ * units) {
            revert InsufficientInactiveBalance();
        }

        uint256 tokenAvailableToMint = _MAX_TOKEN_ID + getERC721QueueLength() - minted;

        if(mintUnit_ > tokenAvailableToMint) {
            revert MintLimitReached();
        }
        
        // Prevent sent Ether to 0x0
        if (treasury == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }
        
        address recipient = payable(treasury);
        (bool success, ) = recipient.call{value: msg.value}("");
        require(success, "Failed to send Ether");

        // Update minter inactiveBalance/_balances.
        // ERC20Storage storage $ = _getERC20Storages();
        _balances[to_] -= (mintUnit_ * units);

        for (uint256 i = 0; i < mintUnit_;) {
            _retrieveOrMintERC721(to_);
            unchecked {
                ++i;
            }
        }
    }

    /************************************
    /******** ERC-20 functions **********
    *************************************/
    /**
     * @notice Function for token approvals
     * @dev This function assumes the operator is attempting to approve
     *       an ERC-721 if valueOrId_ is a possibly valid ERC-721 token id.
     *       Unlike setApprovalForAll, spender_ must be allowed to be 0x0 so
     *       that approval can be revoked.
     */
    function approve(
        address spender_,
        uint256 valueOrId_
    ) public virtual override returns (bool) {
        if (_isValidTokenId(valueOrId_)) {
            erc721Approve(spender_, valueOrId_);
        } else {
            return erc20Approve(spender_, valueOrId_);
        }

        return true;
    }

    /** 
     *  @notice Function for mixed transfers from an operator that may be different than 'from'.
     *  @dev This function assumes the operator is attempting to transfer an ERC-721
     *       if valueOrId is a possible valid token id.
     */
    function transferFrom(
        address from_,
        address to_,
        uint256 valueOrId_
    ) public virtual override returns (bool) {
        if (_isValidTokenId(valueOrId_)) {
            erc721TransferFrom(from_, to_, valueOrId_);
        } else {
        // Intention is to transfer as ERC-20 token (value).
            return erc20TransferFrom(from_, to_, valueOrId_);
        }

        return true;
    }

    /**
     *  @notice Function for ERC-20 transfers.
     *  @dev This function assumes the operator is attempting to transfer as ERC-20
     *       given this function is only supported on the ERC-20 interface.
     *       Treats even large amounts that are valid ERC-721 ids as ERC-20s.
     */
    function transfer(address to_, uint256 value_) public virtual override returns (bool) {
        // Prevent sent tokens to 0x0.
        if (to_ == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }

        // Transferring ERC-20s directly requires the _transfer function.
        // Handles ERC-721 exemptions internally.
        return _transferERC20(msg.sender, to_, value_);
    }

    /**
     * @dev Destroys a `value` amount of tokens from the caller.
     *
     * See {ERC20-_burn}.
     */
    function burn(uint256 value_) public virtual override {
        _transferERC20(_msgSender(), address(0), value_);
    }

    /**
     * @dev Destroys a `value` amount of tokens from `account`, deducting from
     * the caller's allowance.
     *
     * See {ERC20-_burn} and {ERC20-allowance}.
     *
     * Requirements:
     *
     * - the caller must have allowance for ``accounts``'s tokens of at least
     * `value`.
     */
    function burnFrom(address account, uint256 value_) public virtual override {
        _spendAllowance(account, _msgSender(), value_);
        _transferERC20(account, address(0), value_);
    }

    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     * 
     * See {IERC20Permit}
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) public override {
        // permit cannot be used for ERC-721 token approvals, so ensure
        // the value does not fall within the valid range of ERC-721 token ids.
        if (_isValidTokenId(value)) {
            revert InvalidApproval();
        }

        return super.permit(owner, spender, value, deadline, v, r, s);
    }

    /************************************
     ******** ERC-721 functions *********
     ************************************/
    /**
     *  @notice Function for ERC-721 approvals
     */
    function setApprovalForAll(address operator_, bool approved_) public virtual {
        // Prevent approvals to 0x0.
        if (operator_ == address(0)) {
            revert InvalidOperator();
        }
        isApprovedForAll[msg.sender][operator_] = approved_;
        emit ERC721Events.ApprovalForAll(msg.sender, operator_, approved_);
    }

    /**
     *  @notice Function for ERC-721 transfers with contract support.
     *  This function only supports moving valid ERC-721 ids, as it does not exist on the ERC-20 spec and will revert otherwise.
     */
    function safeTransferFrom(
        address from_,
        address to_,
        uint256 id_
    ) public virtual {
        safeTransferFrom(from_, to_, id_, "");
    }

    /**
     *  @notice Function for ERC-721 transfers with contract support and callback data.
     *  This function only supports moving valid ERC-721 ids, as it does not exist on the ERC-20 spec and will revert otherwise.
     */
    function safeTransferFrom(
        address from_,
        address to_,
        uint256 id_,
        bytes memory data_
    ) public virtual {
        if (!_isValidTokenId(id_)) {
            revert InvalidTokenId();
        }

        transferFrom(from_, to_, id_);
        _checkOnERC721Received(from_, to_, id_, data_);
    }

    /**
     *  @notice Double check later if this correct - CK
     */
    function supportsInterface(
        bytes4 interfaceId
    ) public view virtual override returns (bool) {
        return
            interfaceId == type(IWFFTokenERC404).interfaceId ||
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            interfaceId == type(IERC165).interfaceId;
    }

    /************************************
     ******** Internal functions ********
     ************************************/
    
    /**
     *  @notice This is the lowest level ERC-20 transfer function, which
     *          should be used for both normal ERC-20 transfers as well as minting.
     *  Note that this function allows transfers to and from 0x0.
     */
    function _transferERC20(
        address from_,
        address to_,
        uint256 value_
    ) internal virtual returns(bool) {
        // Minting is a special case for which we should not check the balance of
        // the sender, and we should increase the total supply.
        if (from_ == address(0)) {
            _mint(to_, value_);
        } else if (balanceOf(from_) < value_) {
            //Revert if user's token balances are less than `value_`
            revert ERC20InsufficientBalance(from_, balanceOf(from_), value_);
        } else {
            if (inactiveBalance(from_) < value_) {
                //If user has ERC721 tokens, calculate how many ERC721s to withdraw and store,
                //else go straight to `_burn` or `_transfer`
                // ERC20Storage storage $ = _getERC20Storages();
                uint256 diffInValue = value_ - inactiveBalance(from_);
                uint256 tokensToWithdrawAndStore = diffInValue / units + (diffInValue % units == 0 ? 0 : 1);

                for (uint256 i = 0; i < tokensToWithdrawAndStore;) {
                    _withdrawAndStoreERC721(from_);
                    unchecked {
                        ++i;
                    }
                }

                unchecked {
                    // Overflow not possible: balance + value is at most totalSupply, which we know fits into a uint256.
                    _balances[from_] += (tokensToWithdrawAndStore * units);
                } 
            }

            if (to_ == address(0)) {
                _burn(from_, value_);
            } else {
                _transfer(from_, to_, value_);
            }
        }
        return true;
    }

    /**
     *  @notice Consolidated record keeping function for transferring ERC-721s.
     *  @dev Assign the token to the new owner, and remove from the old owner.
     *  Note that this function allows transfers to and from 0x0.
     *  Does not handle ERC-721 exemptions.
     */
    function _transferERC721WithERC20(
        address from_,
        address to_,
        uint256 id_
    ) internal virtual {
        // If this is not a mint, handle record keeping for transfer from previous owner.
        if (from_ != address(0)) {
            // On transfer of an NFT, any previous approval is reset.
            delete getApproved[id_];

            uint256 updatedId = _owned[from_][_owned[from_].length - 1];
            if (updatedId != id_) {
                uint96 updatedIndex = _getOwnedIndex(id_);
                // update _owned for sender
                _owned[from_][updatedIndex] = updatedId;
                // update index for the moved id
                _setOwnedIndex(updatedId, updatedIndex);
            }

            // pop
            _owned[from_].pop();
        }

        // Check if this is a burn.
        if (to_ != address(0)) {
            // If not a burn, update the owner of the token to the new owner.
            // Update owner of the token to the new owner.
            _setOwnerOf(id_, to_);
            // Push token onto the new owner's stack.
            _owned[to_].push(id_);
            // Update index for new owner's stack.
            _setOwnedIndex(id_, uint96(_owned[to_].length - 1));
        } else {
            // If this is a burn, reset the owner of the token to 0x0 by deleting the token from _ownedData.
            delete _ownedData[id_];
        }

        emit ERC721Events.Transfer(from_, to_, id_);
    }

    /**
     *  @notice Internal function for ERC20 minting
     *  @dev This function will allow minting of new ERC20s.
     *       If mintCorrespondingERC721s_ is true, and the recipient is not ERC-721 exempt, it will
     *       also mint the corresponding ERC721s.
     *  Handles ERC-721 exemptions.
     */
    function _mintERC20(address to_, uint256 value_) internal virtual {
        // You cannot mint to the zero address (you can't mint and immediately burn in the same transfer).
        if (to_ == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }

        if (totalSupply() + value_ > ID_ENCODING_PREFIX) {
            revert MintLimitReached();
        }

        _transferERC20(address(0), to_, value_);
    }

    /**
     *  @notice Internal function for ERC-721 minting and retrieval from the bank.
     *  @dev This function will allow minting of new ERC-721s up to the total fractional supply. It will
     *       first try to pull from the bank, and if the bank is empty, it will mint a new token.
     *  Does not handle ERC-721 exemptions.
     */
    function _retrieveOrMintERC721(address to_) internal virtual {
        if (to_ == address(0)) {
            revert ERC721InvalidReceiver(address(0));
        }

        uint256 id;

        if (!_storedERC721Ids.empty()) {
            // If there are any tokens in the bank, use those first.
            // Pop off the end of the queue (FIFO).
            id = _storedERC721Ids.popBack();
        } else {
            // Otherwise, mint a new token, should not be able to go over the total fractional supply.
            ++minted;

            // Reserve max uint256 for approvals
            if (minted > ID_ENCODING_PREFIX + _MAX_TOKEN_ID) {
                revert MintLimitReached();
            }

            id = ID_ENCODING_PREFIX + minted;
        }

        address erc721Owner = _getOwnerOf(id);

        // The token should not already belong to anyone besides 0x0 or this contract.
        // If it does, something is wrong, as this should never happen.
        if (erc721Owner != address(0)) {
            revert AlreadyExists();
        }

        // Transfer the token to the recipient, either transferring from the contract's bank or minting.
        // Does not handle ERC-721 exemptions.
        _transferERC721WithERC20(erc721Owner, to_, id);
    }

    /**
     *  @notice Internal function for ERC-721 deposits to bank (this contract).
     *  @dev This function will allow depositing of ERC-721s to the bank, which can be retrieved by future minters.
     *  Does not handle ERC-721 exemptions.
     */
    function _withdrawAndStoreERC721(address from_) internal virtual {
        if (from_ == address(0)) {
            revert ERC721InvalidSender(address(0));
        }

        // Retrieve the latest token added to the owner's stack (LIFO).
        uint256 id = _owned[from_][_owned[from_].length - 1];

        // Transfer to 0x0.
        // Does not handle ERC-721 exemptions.
        _transferERC721WithERC20(from_, address(0), id);

        // Record the token in the contract's bank queue.
        _storedERC721Ids.pushFront(id);
    }

    /**
     * @dev Private function to invoke {IERC721Receiver-onERC721Received} on a target address. This will revert if the
     * recipient doesn't accept the token transfer. The call is not executed if the target address is not a contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param data bytes optional data to send along with the call
     */
    function _checkOnERC721Received(address from, address to, uint256 tokenId, bytes memory data) private {
        if (to.code.length > 0) {
            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, data) returns (bytes4 retval) {
                if (retval != IERC721Receiver.onERC721Received.selector) {
                    revert ERC721InvalidReceiver(to);
                }
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert ERC721InvalidReceiver(to);
                } else {
                    // @solidity memory-safe-assembly
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        }
    }

    // function _getERC20Storages() private pure returns (ERC20Storage storage $) {
    //     assembly {
    //         $.slot := 0x52c63247e1f47db19d5ce0460030c497f067ca4cebf71ba98eeadabe20bace00
    //     }
    // }

    /**
     * @notice For a token token id to be considered valid, it just needs
     *          to fall within the range of possible token ids, it does not
     *          necessarily have to be minted yet.
     */ 
    function _isValidTokenId(uint256 id_) internal view returns (bool) {
        return id_ > ID_ENCODING_PREFIX && id_ <= ID_ENCODING_PREFIX + _MAX_TOKEN_ID;
    }

    function _getOwnerOf(
        uint256 id_
    ) internal view virtual returns (address ownerOf_) {
        return _ownedData[id_].ownerOf;
    }

    function _setOwnerOf(uint256 id_, address owner_) internal virtual {
        _ownedData[id_].ownerOf = owner_;
    }

    function _getOwnedIndex(
        uint256 id_
    ) internal view virtual returns (uint96 ownedIndex_) {
        return _ownedData[id_].ownedIndex;
    }

    function _setOwnedIndex(uint256 id_, uint96 index_) internal virtual {
        _ownedData[id_].ownedIndex = index_;
    }

    /**
     * @dev Returns whether `tokenId` exists.
     *
     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
     *
     * Tokens start existing when they are minted (`_mint`),
     * and stop existing when they are burned (`_burn`).
     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _getOwnerOf(tokenId) != address(0);
    }

    function _baseURI() internal view virtual returns (string memory) {
        return baseTokenURI;
    }

    /************************************
     ******** Public View functions *****
     ************************************/
    /**  
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view override returns (uint256) {
        return inactiveBalance(account) + activeBalance(account);
    }

    /**  
     * @notice tokenURI must be implemented by child contract
     */ 
    function tokenURI(uint256 id_) public view virtual returns (string memory);

    /**  
     * @dev Nonconverted-721 ERC20 balance.
     */
    function inactiveBalance(address account) public view virtual returns (uint256) {
        // ERC20Storage storage $ = _getERC20Storages();
        return _balances[account];
    }

    /**  
     * @dev converted-721 ERC20 balance.
     */
    function activeBalance(address account) public view virtual returns (uint256) {
        return erc721BalanceOf(account) * units;
    }

    /**  
     * @notice Function to find owner of a given ERC-721 token
     */
    function ownerOf(
        uint256 id_
    ) public view virtual returns (address erc721Owner) {
        erc721Owner = _getOwnerOf(id_);

        if (!_isValidTokenId(id_)) {
            revert InvalidTokenId();
        }
        
        if (erc721Owner == address(0)) {
            revert NotFound();
        }
    }

    function owned(
        address owner_
    ) public view virtual returns (uint256[] memory) {
        return _owned[owner_];
    }

    function erc721BalanceOf(
        address owner_
    ) public view virtual returns (uint256) {
        return _owned[owner_].length;
    }

    function erc721TotalSupply() public view virtual returns (uint256) {
        return minted;
    }

    function erc721MaxTokenId() public view virtual returns (uint256) {
        return ID_ENCODING_PREFIX + _MAX_TOKEN_ID;
    }

    function getERC721QueueLength() public view virtual returns (uint256) {
        return _storedERC721Ids.length();
    }

    function getERC721TokensInQueue(
        uint256 start_,
        uint256 count_
    ) public view virtual returns (uint256[] memory) {
        uint256[] memory tokensInQueue = new uint256[](count_);

        for (uint256 i = start_; i < start_ + count_; ) {
            tokensInQueue[i - start_] = _storedERC721Ids.at(i);

            unchecked {
                ++i;
            }
        }

        return tokensInQueue;
    }

    /************************************
     ******** Admin functions ***********
     ************************************/
    function init404(uint256 unit404Decimals) external onlyRole(DEFAULT_ADMIN_ROLE) {
        units = 10 ** unit404Decimals;
    }

    function setMaxTokenId(uint256 _cap) external onlyRole(DEFAULT_ADMIN_ROLE) {
        require(_cap > minted, "Less than minted");
        _MAX_TOKEN_ID = _cap;
    }

    function setBaseURI(string memory baseURI) public onlyRole(DEFAULT_ADMIN_ROLE) {
        baseTokenURI = baseURI;
    }

    function setMint721Cost(uint256 _mintingCost) public onlyRole(DEFAULT_ADMIN_ROLE) {
        mintingCost = _mintingCost;
    }

    function setTreasuryAddress(address _treasury) public onlyRole(DEFAULT_ADMIN_ROLE) {
        treasury = _treasury;
    }

    function recoverToken(
        address token,
        address _recipient,
        uint256 amount
    ) external onlyRole(DEFAULT_ADMIN_ROLE) {
        // Prevent sent tokens to 0x0.
        if (_recipient == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }
        IERC20(token).transfer(_recipient, amount);
    }

    function recoverEth(
        uint256 safeAmount,
        address _recipient
    ) external onlyRole(DEFAULT_ADMIN_ROLE) {
        // Prevent sent tokens to 0x0.
        if (_recipient == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }

        address recipient = payable(_recipient);
        (bool success, ) = recipient.call{value: safeAmount}("");
        require(success, "Failed to send Ether");
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
          

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {ERC404} from "../ERC404.sol";
import {IPeripheryImmutableState} from "@uniswap/v3-periphery/contracts/interfaces/IPeripheryImmutableState.sol";

abstract contract ERC404UniswapV3Exempt is ERC404 {
  error ERC404UniswapV3ExemptFactoryMismatch();
  error ERC404UniswapV3ExemptWETH9Mismatch();

  constructor(address uniswapV3Router_, address uniswapV3NonfungiblePositionManager_) {
    IPeripheryImmutableState uniswapV3Router = IPeripheryImmutableState(
      uniswapV3Router_
    );

    // Set the Uniswap v3 swap router as exempt.
    _setERC721TransferExempt(uniswapV3Router_, true);

    IPeripheryImmutableState uniswapV3NonfungiblePositionManager = IPeripheryImmutableState(
      uniswapV3NonfungiblePositionManager_
    );

    // Set the Uniswap v3 nonfungible position manager as exempt.
    _setERC721TransferExempt(uniswapV3NonfungiblePositionManager_, true);

    // Require the Uniswap v3 factory from the position manager and the swap router to be the same.
    if (uniswapV3Router.factory() != uniswapV3NonfungiblePositionManager.factory()) {
      revert ERC404UniswapV3ExemptFactoryMismatch();
    }
 
    // Require the Uniswap v3 WETH9 from the position manager and the swap router to be the same.
    if (uniswapV3Router.WETH9() != uniswapV3NonfungiblePositionManager.WETH9()) {
      revert ERC404UniswapV3ExemptWETH9Mismatch();
    }

    uint24[4] memory feeTiers = [uint24(100), uint24(500), uint24(3_000), uint24(10_000)];

    // Determine the Uniswap v3 pair address for this token.
    for (uint256 i = 0; i < feeTiers.length; ) {
      address uniswapV3Pair = _getUniswapV3Pair(
        uniswapV3Router.factory(),
        uniswapV3Router.WETH9(),
        feeTiers[i]
      );

      // Set the Uniswap v3 pair as exempt.
      _setERC721TransferExempt(uniswapV3Pair, true);

      unchecked {
        ++i;
      }
    }
  }

  function _getUniswapV3Pair(
    address uniswapV3Factory_,
    address weth_,
    uint24 fee_
  ) private view returns (address) {
    address thisAddress = address(this);

    (address token0, address token1) = thisAddress < weth_
      ? (thisAddress, weth_)
      : (weth_, thisAddress);

    return
      address(
        uint160(
          uint256(
            keccak256(
              abi.encodePacked(
                hex"ff",
                uniswapV3Factory_,
                keccak256(abi.encode(token0, token1, fee_)),
                hex"e34f199b19b2b4f47f68442619d555527d244f78a3297ea89325f843f87b8b54"
              )
            )
          )
        )
      );
  }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.2) (utils/cryptography/MerkleProof.sol)

pragma solidity ^0.8.0;

/**
 * @dev These functions deal with verification of Merkle Tree proofs.
 *
 * The tree and the proofs can be generated using our
 * https://github.com/OpenZeppelin/merkle-tree[JavaScript library].
 * You will find a quickstart guide in the readme.
 *
 * WARNING: You should avoid using leaf values that are 64 bytes long prior to
 * hashing, or use a hash function other than keccak256 for hashing leaves.
 * This is because the concatenation of a sorted pair of internal nodes in
 * the merkle tree could be reinterpreted as a leaf value.
 * OpenZeppelin's JavaScript library generates merkle trees that are safe
 * against this attack out of the box.
 */
library MerkleProof {
    /**
     * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
     * defined by `root`. For this, a `proof` must be provided, containing
     * sibling hashes on the branch from the leaf to the root of the tree. Each
     * pair of leaves and each pair of pre-images are assumed to be sorted.
     */
    function verify(bytes32[] memory proof, bytes32 root, bytes32 leaf) internal pure returns (bool) {
        return processProof(proof, leaf) == root;
    }

    /**
     * @dev Calldata version of {verify}
     *
     * _Available since v4.7._
     */
    function verifyCalldata(bytes32[] calldata proof, bytes32 root, bytes32 leaf) internal pure returns (bool) {
        return processProofCalldata(proof, leaf) == root;
    }

    /**
     * @dev Returns the rebuilt hash obtained by traversing a Merkle tree up
     * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
     * hash matches the root of the tree. When processing the proof, the pairs
     * of leafs & pre-images are assumed to be sorted.
     *
     * _Available since v4.4._
     */
    function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
        bytes32 computedHash = leaf;
        for (uint256 i = 0; i < proof.length; i++) {
            computedHash = _hashPair(computedHash, proof[i]);
        }
        return computedHash;
    }

    /**
     * @dev Calldata version of {processProof}
     *
     * _Available since v4.7._
     */
    function processProofCalldata(bytes32[] calldata proof, bytes32 leaf) internal pure returns (bytes32) {
        bytes32 computedHash = leaf;
        for (uint256 i = 0; i < proof.length; i++) {
            computedHash = _hashPair(computedHash, proof[i]);
        }
        return computedHash;
    }

    /**
     * @dev Returns true if the `leaves` can be simultaneously proven to be a part of a merkle tree defined by
     * `root`, according to `proof` and `proofFlags` as described in {processMultiProof}.
     *
     * CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.
     *
     * _Available since v4.7._
     */
    function multiProofVerify(
        bytes32[] memory proof,
        bool[] memory proofFlags,
        bytes32 root,
        bytes32[] memory leaves
    ) internal pure returns (bool) {
        return processMultiProof(proof, proofFlags, leaves) == root;
    }

    /**
     * @dev Calldata version of {multiProofVerify}
     *
     * CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.
     *
     * _Available since v4.7._
     */
    function multiProofVerifyCalldata(
        bytes32[] calldata proof,
        bool[] calldata proofFlags,
        bytes32 root,
        bytes32[] memory leaves
    ) internal pure returns (bool) {
        return processMultiProofCalldata(proof, proofFlags, leaves) == root;
    }

    /**
     * @dev Returns the root of a tree reconstructed from `leaves` and sibling nodes in `proof`. The reconstruction
     * proceeds by incrementally reconstructing all inner nodes by combining a leaf/inner node with either another
     * leaf/inner node or a proof sibling node, depending on whether each `proofFlags` item is true or false
     * respectively.
     *
     * CAUTION: Not all merkle trees admit multiproofs. To use multiproofs, it is sufficient to ensure that: 1) the tree
     * is complete (but not necessarily perfect), 2) the leaves to be proven are in the opposite order they are in the
     * tree (i.e., as seen from right to left starting at the deepest layer and continuing at the next layer).
     *
     * _Available since v4.7._
     */
    function processMultiProof(
        bytes32[] memory proof,
        bool[] memory proofFlags,
        bytes32[] memory leaves
    ) internal pure returns (bytes32 merkleRoot) {
        // This function rebuilds the root hash by traversing the tree up from the leaves. The root is rebuilt by
        // consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
        // `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
        // the merkle tree.
        uint256 leavesLen = leaves.length;
        uint256 proofLen = proof.length;
        uint256 totalHashes = proofFlags.length;

        // Check proof validity.
        require(leavesLen + proofLen - 1 == totalHashes, "MerkleProof: invalid multiproof");

        // The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
        // `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
        bytes32[] memory hashes = new bytes32[](totalHashes);
        uint256 leafPos = 0;
        uint256 hashPos = 0;
        uint256 proofPos = 0;
        // At each step, we compute the next hash using two values:
        // - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
        //   get the next hash.
        // - depending on the flag, either another value from the "main queue" (merging branches) or an element from the
        //   `proof` array.
        for (uint256 i = 0; i < totalHashes; i++) {
            bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
            bytes32 b = proofFlags[i]
                ? (leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++])
                : proof[proofPos++];
            hashes[i] = _hashPair(a, b);
        }

        if (totalHashes > 0) {
            require(proofPos == proofLen, "MerkleProof: invalid multiproof");
            unchecked {
                return hashes[totalHashes - 1];
            }
        } else if (leavesLen > 0) {
            return leaves[0];
        } else {
            return proof[0];
        }
    }

    /**
     * @dev Calldata version of {processMultiProof}.
     *
     * CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.
     *
     * _Available since v4.7._
     */
    function processMultiProofCalldata(
        bytes32[] calldata proof,
        bool[] calldata proofFlags,
        bytes32[] memory leaves
    ) internal pure returns (bytes32 merkleRoot) {
        // This function rebuilds the root hash by traversing the tree up from the leaves. The root is rebuilt by
        // consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
        // `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
        // the merkle tree.
        uint256 leavesLen = leaves.length;
        uint256 proofLen = proof.length;
        uint256 totalHashes = proofFlags.length;

        // Check proof validity.
        require(leavesLen + proofLen - 1 == totalHashes, "MerkleProof: invalid multiproof");

        // The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
        // `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
        bytes32[] memory hashes = new bytes32[](totalHashes);
        uint256 leafPos = 0;
        uint256 hashPos = 0;
        uint256 proofPos = 0;
        // At each step, we compute the next hash using two values:
        // - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
        //   get the next hash.
        // - depending on the flag, either another value from the "main queue" (merging branches) or an element from the
        //   `proof` array.
        for (uint256 i = 0; i < totalHashes; i++) {
            bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
            bytes32 b = proofFlags[i]
                ? (leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++])
                : proof[proofPos++];
            hashes[i] = _hashPair(a, b);
        }

        if (totalHashes > 0) {
            require(proofPos == proofLen, "MerkleProof: invalid multiproof");
            unchecked {
                return hashes[totalHashes - 1];
            }
        } else if (leavesLen > 0) {
            return leaves[0];
        } else {
            return proof[0];
        }
    }

    function _hashPair(bytes32 a, bytes32 b) private pure returns (bytes32) {
        return a < b ? _efficientHash(a, b) : _efficientHash(b, a);
    }

    function _efficientHash(bytes32 a, bytes32 b) private pure returns (bytes32 value) {
        /// @solidity memory-safe-assembly
        assembly {
            mstore(0x00, a)
            mstore(0x20, b)
            value := keccak256(0x00, 0x40)
        }
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165Upgradeable {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20Upgradeable {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 amount) external returns (bool);
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (security/Pausable.sol)

pragma solidity ^0.8.0;

import "../utils/ContextUpgradeable.sol";
import {Initializable} from "../proxy/utils/Initializable.sol";

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract PausableUpgradeable is Initializable, ContextUpgradeable {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    function __Pausable_init() internal onlyInitializing {
        __Pausable_init_unchained();
    }

    function __Pausable_init_unchained() internal onlyInitializing {
        _paused = false;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        _requireNotPaused();
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        _requirePaused();
        _;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Throws if the contract is paused.
     */
    function _requireNotPaused() internal view virtual {
        require(!paused(), "Pausable: paused");
    }

    /**
     * @dev Throws if the contract is not paused.
     */
    function _requirePaused() internal view virtual {
        require(paused(), "Pausable: not paused");
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[49] private __gap;
}
          

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

interface IERC404MerkleClaim {
  error AirdropAlreadyClaimed();
  error NotEligibleForAirdrop();
  error AirdropIsClosed();

  function verifyProof(
    bytes32[] memory proof_,
    address claimer_,
    uint256 value_
  ) external view returns (bool);

  function airdropMint(bytes32[] memory proof_, uint256 value_) external;
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;

import "./IERC20Upgradeable.sol";
import "./extensions/IERC20MetadataUpgradeable.sol";
import "../../utils/ContextUpgradeable.sol";
import {Initializable} from "../../proxy/utils/Initializable.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * The default value of {decimals} is 18. To change this, you should override
 * this function so it returns a different value.
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20Upgradeable is Initializable, ContextUpgradeable, IERC20Upgradeable, IERC20MetadataUpgradeable {
    mapping(address => uint256) internal _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    function __ERC20_init(string memory name_, string memory symbol_) internal onlyInitializing {
        __ERC20_init_unchained(name_, symbol_);
    }

    function __ERC20_init_unchained(string memory name_, string memory symbol_) internal onlyInitializing {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the default value returned by this function, unless
     * it's overridden.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address from, address to, uint256 amount) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `from` to `to`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     */
    function _transfer(address from, address to, uint256 amount) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
            // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
            // decrementing then incrementing.
            _balances[to] += amount;
        }

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        unchecked {
            // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
            _balances[account] += amount;
        }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
            // Overflow not possible: amount <= accountBalance <= totalSupply.
            _totalSupply -= amount;
        }

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    function _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(address from, address to, uint256 amount) internal virtual {}

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[45] private __gap;
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/structs/DoubleEndedQueue.sol)
// Modified by Pandora Labs to support native packed operations
pragma solidity ^0.8.18;

/**
 * @dev A sequence of items with the ability to efficiently push and pop items (i.e. insert and remove) on both ends of
 * the sequence (called front and back). Among other access patterns, it can be used to implement efficient LIFO and
 * FIFO queues. Storage use is optimized, and all operations are O(1) constant time. This includes {clear}, given that
 * the existing queue contents are left in storage.
 *
 * The struct is called `Uint16Deque`. And is designed for packed uint16 values, though this approach can be  
 * extrapolated to different implementations. This data structure can only be used in storage, and not in memory.
 *
 * ```solidity
 * PackedDoubleEndedQueue.Uint16Deque queue;
 * ```
 */
library PackedDoubleEndedQueue {
  uint128 constant SLOT_MASK = (1 << 64) - 1;
  uint128 constant INDEX_MASK = SLOT_MASK << 64;

  uint256 constant SLOT_DATA_MASK = (1 << 16) - 1;

  /**
   * @dev An operation (e.g. {front}) couldn't be completed due to the queue being empty.
   */
  error QueueEmpty();

  /**
   * @dev A push operation couldn't be completed due to the queue being full.
   */
  error QueueFull();

  /**
   * @dev An operation (e.g. {at}) couldn't be completed due to an index being out of bounds.
   */
  error QueueOutOfBounds();

  /**
   * @dev Invalid slot.
   */
  error InvalidSlot();

  /**
   * @dev Indices and slots are 64 bits to fit within a single storage slot.
   *
   * Struct members have an underscore prefix indicating that they are "private" and should not be read or written to
   * directly. Use the functions provided below instead. Modifying the struct manually may violate assumptions and
   * lead to unexpected behavior.
   *
   * The first item is at data[begin] and the last item is at data[end - 1]. This range can wrap around.
   */
  struct Uint16Deque {
    uint64 _beginIndex;
    uint64 _beginSlot;
    uint64 _endIndex;
    uint64 _endSlot;
    mapping(uint64 index => uint256) _data;
  }

  /**
   * @dev Removes the item at the end of the queue and returns it.
   *
   * Reverts with {QueueEmpty} if the queue is empty.
   */
  function popBack(
    Uint16Deque storage deque
  ) internal returns (uint16 value) {
    unchecked {
      uint64 backIndex = deque._endIndex;
      uint64 backSlot = deque._endSlot;

      if (backIndex == deque._beginIndex && backSlot == deque._beginSlot) revert QueueEmpty();

      if (backSlot == 0) {
        --backIndex;
        backSlot = 15;
      } else {
        --backSlot;
      }

      uint256 data = deque._data[backIndex];

      value = _getEntry(data, backSlot);
      deque._data[backIndex] = _setData(data, backSlot, 0);

      deque._endIndex = backIndex;
      deque._endSlot = backSlot;
    }
  }

  /**
   * @dev Inserts an item at the beginning of the queue.
   *
   * Reverts with {QueueFull} if the queue is full.
   */
  function pushFront(Uint16Deque storage deque, uint16 value_) internal {
    unchecked {
      uint64 frontIndex = deque._beginIndex;
      uint64 frontSlot = deque._beginSlot;

      if (frontSlot == 0) {
        --frontIndex;
        frontSlot = 15;
      } else {
        --frontSlot;
      }

      if (frontIndex == deque._endIndex) revert QueueFull();

      deque._data[frontIndex] = _setData(deque._data[frontIndex], frontSlot, value_);
      deque._beginIndex = frontIndex;
      deque._beginSlot = frontSlot;
    }
  }

  /**
   * @dev Return the item at a position in the queue given by `index`, with the first item at 0 and last item at
   * `length(deque) - 1`.
   *
   * Reverts with `QueueOutOfBounds` if the index is out of bounds.
   */
  function at(
    Uint16Deque storage deque,
    uint256 index_
  ) internal view returns (uint16 value) {
    if (index_ >= length(deque) * 16) revert QueueOutOfBounds();

    unchecked {
      return _getEntry(
        deque._data[deque._beginIndex + uint64(deque._beginSlot + (index_ % 16)) / 16 + uint64(index_ / 16)], 
        uint64(((deque._beginSlot + index_) % 16))
      );
    }
  }

  /**
   * @dev Returns the number of items in the queue.
   */
  function length(Uint16Deque storage deque) internal view returns (uint256) {
    unchecked {
      return (16 - deque._beginSlot) + deque._endSlot + deque._endIndex * 16 - deque._beginIndex * 16 - 16;
    }
  }

  /**
   * @dev Returns true if the queue is empty.
   */
  function empty(Uint16Deque storage deque) internal view returns (bool) {
    return deque._endSlot == deque._beginSlot && deque._endIndex == deque._beginIndex;
  }

  function _setData(uint256 data_, uint64 slot_, uint16 value) private pure returns (uint256) {
    return (data_ & (~_getSlotMask(slot_))) + (uint256(value) << (16 * slot_));
  }

  function _getEntry(uint256 data, uint64 slot_) private pure returns (uint16) {
    return uint16((data & _getSlotMask(slot_)) >> (16 * slot_));
  }

  function _getSlotMask(uint64 slot_) private pure returns (uint256) {
    return SLOT_DATA_MASK << (slot_ * 16);
  }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/structs/DoubleEndedQueue.sol)
// Modified by Pandora Labs to support native uint256 operations
pragma solidity ^0.8.18;

/**
 * @dev A sequence of items with the ability to efficiently push and pop items (i.e. insert and remove) on both ends of
 * the sequence (called front and back). Among other access patterns, it can be used to implement efficient LIFO and
 * FIFO queues. Storage use is optimized, and all operations are O(1) constant time. This includes {clear}, given that
 * the existing queue contents are left in storage.
 *
 * The struct is called `Uint256Deque`. This data structure can only be used in storage, and not in memory.
 *
 * ```solidity
 * DoubleEndedQueue.Uint256Deque queue;
 * ```
 */
library DoubleEndedQueue {
  /**
   * @dev An operation (e.g. {front}) couldn't be completed due to the queue being empty.
   */
  error QueueEmpty();

  /**
   * @dev A push operation couldn't be completed due to the queue being full.
   */
  error QueueFull();

  /**
   * @dev An operation (e.g. {at}) couldn't be completed due to an index being out of bounds.
   */
  error QueueOutOfBounds();

  /**
   * @dev Indices are 128 bits so begin and end are packed in a single storage slot for efficient access.
   *
   * Struct members have an underscore prefix indicating that they are "private" and should not be read or written to
   * directly. Use the functions provided below instead. Modifying the struct manually may violate assumptions and
   * lead to unexpected behavior.
   *
   * The first item is at data[begin] and the last item is at data[end - 1]. This range can wrap around.
   */
  struct Uint256Deque {
    uint128 _begin;
    uint128 _end;
    mapping(uint128 index => uint256) _data;
  }

  /**
   * @dev Inserts an item at the end of the queue.
   *
   * Reverts with {QueueFull} if the queue is full.
   */
  function pushBack(Uint256Deque storage deque, uint256 value) internal {
    unchecked {
      uint128 backIndex = deque._end;
      if (backIndex + 1 == deque._begin) revert QueueFull();
      deque._data[backIndex] = value;
      deque._end = backIndex + 1;
    }
  }

  /**
   * @dev Removes the item at the end of the queue and returns it.
   *
   * Reverts with {QueueEmpty} if the queue is empty.
   */
  function popBack(
    Uint256Deque storage deque
  ) internal returns (uint256 value) {
    unchecked {
      uint128 backIndex = deque._end;
      if (backIndex == deque._begin) revert QueueEmpty();
      --backIndex;
      value = deque._data[backIndex];
      delete deque._data[backIndex];
      deque._end = backIndex;
    }
  }

  /**
   * @dev Inserts an item at the beginning of the queue.
   *
   * Reverts with {QueueFull} if the queue is full.
   */
  function pushFront(Uint256Deque storage deque, uint256 value) internal {
    unchecked {
      uint128 frontIndex = deque._begin - 1;
      if (frontIndex == deque._end) revert QueueFull();
      deque._data[frontIndex] = value;
      deque._begin = frontIndex;
    }
  }

  /**
   * @dev Removes the item at the beginning of the queue and returns it.
   *
   * Reverts with `QueueEmpty` if the queue is empty.
   */
  function popFront(
    Uint256Deque storage deque
  ) internal returns (uint256 value) {
    unchecked {
      uint128 frontIndex = deque._begin;
      if (frontIndex == deque._end) revert QueueEmpty();
      value = deque._data[frontIndex];
      delete deque._data[frontIndex];
      deque._begin = frontIndex + 1;
    }
  }

  /**
   * @dev Returns the item at the beginning of the queue.
   *
   * Reverts with `QueueEmpty` if the queue is empty.
   */
  function front(
    Uint256Deque storage deque
  ) internal view returns (uint256 value) {
    if (empty(deque)) revert QueueEmpty();
    return deque._data[deque._begin];
  }

  /**
   * @dev Returns the item at the end of the queue.
   *
   * Reverts with `QueueEmpty` if the queue is empty.
   */
  function back(
    Uint256Deque storage deque
  ) internal view returns (uint256 value) {
    if (empty(deque)) revert QueueEmpty();
    unchecked {
      return deque._data[deque._end - 1];
    }
  }

  /**
   * @dev Return the item at a position in the queue given by `index`, with the first item at 0 and last item at
   * `length(deque) - 1`.
   *
   * Reverts with `QueueOutOfBounds` if the index is out of bounds.
   */
  function at(
    Uint256Deque storage deque,
    uint256 index
  ) internal view returns (uint256 value) {
    if (index >= length(deque)) revert QueueOutOfBounds();
    // By construction, length is a uint128, so the check above ensures that index can be safely downcast to uint128
    unchecked {
      return deque._data[deque._begin + uint128(index)];
    }
  }

  /**
   * @dev Resets the queue back to being empty.
   *
   * NOTE: The current items are left behind in storage. This does not affect the functioning of the queue, but misses
   * out on potential gas refunds.
   */
  function clear(Uint256Deque storage deque) internal {
    deque._begin = 0;
    deque._end = 0;
  }

  /**
   * @dev Returns the number of items in the queue.
   */
  function length(Uint256Deque storage deque) internal view returns (uint256) {
    unchecked {
      return uint256(deque._end - deque._begin);
    }
  }

  /**
   * @dev Returns true if the queue is empty.
   */
  function empty(Uint256Deque storage deque) internal view returns (bool) {
    return deque._end == deque._begin;
  }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (interfaces/IERC721Receiver.sol)

pragma solidity ^0.8.0;

import "../token/ERC721/IERC721Receiver.sol";
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.4) (utils/Context.sol)

pragma solidity ^0.8.0;
import {Initializable} from "../proxy/utils/Initializable.sol";

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract ContextUpgradeable is Initializable {
    function __Context_init() internal onlyInitializing {
    }

    function __Context_init_unchained() internal onlyInitializing {
    }
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    function _contextSuffixLength() internal view virtual returns (uint256) {
        return 0;
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/math/Math.sol)

pragma solidity ^0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library MathUpgradeable {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }

    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
     * with further edits by Uniswap Labs also under MIT license.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod0 := mul(x, y)
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                // The surrounding unchecked block does not change this fact.
                // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            require(denominator > prod1, "Math: mulDiv overflow");

            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
            // See https://cs.stackexchange.com/q/138556/92363.

            // Does not overflow because the denominator cannot be zero at this stage in the function.
            uint256 twos = denominator & (~denominator + 1);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;

            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;

            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
            // in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256

            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10 ** 64) {
                value /= 10 ** 64;
                result += 64;
            }
            if (value >= 10 ** 32) {
                value /= 10 ** 32;
                result += 32;
            }
            if (value >= 10 ** 16) {
                value /= 10 ** 16;
                result += 16;
            }
            if (value >= 10 ** 8) {
                value /= 10 ** 8;
                result += 8;
            }
            if (value >= 10 ** 4) {
                value /= 10 ** 4;
                result += 4;
            }
            if (value >= 10 ** 2) {
                value /= 10 ** 2;
                result += 2;
            }
            if (value >= 10 ** 1) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256, rounded down, of a positive value.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
        }
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (interfaces/IERC165.sol)

pragma solidity ^0.8.0;

import "../utils/introspection/IERC165.sol";
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (interfaces/draft-IERC1822.sol)

pragma solidity ^0.8.0;

/**
 * @dev ERC1822: Universal Upgradeable Proxy Standard (UUPS) documents a method for upgradeability through a simplified
 * proxy whose upgrades are fully controlled by the current implementation.
 */
interface IERC1822ProxiableUpgradeable {
    /**
     * @dev Returns the storage slot that the proxiable contract assumes is being used to store the implementation
     * address.
     *
     * IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks
     * bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this
     * function revert if invoked through a proxy.
     */
    function proxiableUUID() external view returns (bytes32);
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/math/Math.sol)

pragma solidity ^0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }

    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
     * with further edits by Uniswap Labs also under MIT license.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod0 := mul(x, y)
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                // The surrounding unchecked block does not change this fact.
                // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            require(denominator > prod1, "Math: mulDiv overflow");

            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
            // See https://cs.stackexchange.com/q/138556/92363.

            // Does not overflow because the denominator cannot be zero at this stage in the function.
            uint256 twos = denominator & (~denominator + 1);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;

            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;

            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
            // in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256

            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10 ** 64) {
                value /= 10 ** 64;
                result += 64;
            }
            if (value >= 10 ** 32) {
                value /= 10 ** 32;
                result += 32;
            }
            if (value >= 10 ** 16) {
                value /= 10 ** 16;
                result += 16;
            }
            if (value >= 10 ** 8) {
                value /= 10 ** 8;
                result += 8;
            }
            if (value >= 10 ** 4) {
                value /= 10 ** 4;
                result += 4;
            }
            if (value >= 10 ** 2) {
                value /= 10 ** 2;
                result += 2;
            }
            if (value >= 10 ** 1) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256, rounded down, of a positive value.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
        }
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/cryptography/ECDSA.sol)

pragma solidity ^0.8.0;

import "../StringsUpgradeable.sol";

/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSAUpgradeable {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS,
        InvalidSignatureV // Deprecated in v4.8
    }

    function _throwError(RecoverError error) private pure {
        if (error == RecoverError.NoError) {
            return; // no error: do nothing
        } else if (error == RecoverError.InvalidSignature) {
            revert("ECDSA: invalid signature");
        } else if (error == RecoverError.InvalidSignatureLength) {
            revert("ECDSA: invalid signature length");
        } else if (error == RecoverError.InvalidSignatureS) {
            revert("ECDSA: invalid signature 's' value");
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature` or error string. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     *
     * Documentation for signature generation:
     * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
     * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {
        if (signature.length == 65) {
            bytes32 r;
            bytes32 s;
            uint8 v;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            /// @solidity memory-safe-assembly
            assembly {
                r := mload(add(signature, 0x20))
                s := mload(add(signature, 0x40))
                v := byte(0, mload(add(signature, 0x60)))
            }
            return tryRecover(hash, v, r, s);
        } else {
            return (address(0), RecoverError.InvalidSignatureLength);
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, signature);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
     *
     * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, bytes32 r, bytes32 vs) internal pure returns (address, RecoverError) {
        bytes32 s = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
        uint8 v = uint8((uint256(vs) >> 255) + 27);
        return tryRecover(hash, v, r, s);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
     *
     * _Available since v4.2._
     */
    function recover(bytes32 hash, bytes32 r, bytes32 vs) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, r, vs);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `v`,
     * `r` and `s` signature fields separately.
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) internal pure returns (address, RecoverError) {
        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return (address(0), RecoverError.InvalidSignatureS);
        }

        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        if (signer == address(0)) {
            return (address(0), RecoverError.InvalidSignature);
        }

        return (signer, RecoverError.NoError);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function recover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, v, r, s);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from a `hash`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32 message) {
        // 32 is the length in bytes of hash,
        // enforced by the type signature above
        /// @solidity memory-safe-assembly
        assembly {
            mstore(0x00, "\x19Ethereum Signed Message:\n32")
            mstore(0x1c, hash)
            message := keccak256(0x00, 0x3c)
        }
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from `s`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n", StringsUpgradeable.toString(s.length), s));
    }

    /**
     * @dev Returns an Ethereum Signed Typed Data, created from a
     * `domainSeparator` and a `structHash`. This produces hash corresponding
     * to the one signed with the
     * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
     * JSON-RPC method as part of EIP-712.
     *
     * See {recover}.
     */
    function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32 data) {
        /// @solidity memory-safe-assembly
        assembly {
            let ptr := mload(0x40)
            mstore(ptr, "\x19\x01")
            mstore(add(ptr, 0x02), domainSeparator)
            mstore(add(ptr, 0x22), structHash)
            data := keccak256(ptr, 0x42)
        }
    }

    /**
     * @dev Returns an Ethereum Signed Data with intended validator, created from a
     * `validator` and `data` according to the version 0 of EIP-191.
     *
     * See {recover}.
     */
    function toDataWithIntendedValidatorHash(address validator, bytes memory data) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19\x00", validator, data));
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (interfaces/IERC5267.sol)

pragma solidity ^0.8.0;

interface IERC5267Upgradeable {
    /**
     * @dev MAY be emitted to signal that the domain could have changed.
     */
    event EIP712DomainChanged();

    /**
     * @dev returns the fields and values that describe the domain separator used by this contract for EIP-712
     * signature.
     */
    function eip712Domain()
        external
        view
        returns (
            bytes1 fields,
            string memory name,
            string memory version,
            uint256 chainId,
            address verifyingContract,
            bytes32 salt,
            uint256[] memory extensions
        );
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/SignedMath.sol)

pragma solidity ^0.8.0;

/**
 * @dev Standard signed math utilities missing in the Solidity language.
 */
library SignedMath {
    /**
     * @dev Returns the largest of two signed numbers.
     */
    function max(int256 a, int256 b) internal pure returns (int256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two signed numbers.
     */
    function min(int256 a, int256 b) internal pure returns (int256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two signed numbers without overflow.
     * The result is rounded towards zero.
     */
    function average(int256 a, int256 b) internal pure returns (int256) {
        // Formula from the book "Hacker's Delight"
        int256 x = (a & b) + ((a ^ b) >> 1);
        return x + (int256(uint256(x) >> 255) & (a ^ b));
    }

    /**
     * @dev Returns the absolute unsigned value of a signed value.
     */
    function abs(int256 n) internal pure returns (uint256) {
        unchecked {
            // must be unchecked in order to support `n = type(int256).min`
            return uint256(n >= 0 ? n : -n);
        }
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (access/AccessControl.sol)

pragma solidity ^0.8.0;

import "./IAccessControlUpgradeable.sol";
import "../utils/ContextUpgradeable.sol";
import "../utils/StringsUpgradeable.sol";
import "../utils/introspection/ERC165Upgradeable.sol";
import {Initializable} from "../proxy/utils/Initializable.sol";

/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms. This is a lightweight version that doesn't allow enumerating role
 * members except through off-chain means by accessing the contract event logs. Some
 * applications may benefit from on-chain enumerability, for those cases see
 * {AccessControlEnumerable}.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```solidity
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```solidity
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it. We recommend using {AccessControlDefaultAdminRules}
 * to enforce additional security measures for this role.
 */
abstract contract AccessControlUpgradeable is Initializable, ContextUpgradeable, IAccessControlUpgradeable, ERC165Upgradeable {
    struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
    }

    mapping(bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /**
     * @dev Modifier that checks that an account has a specific role. Reverts
     * with a standardized message including the required role.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     *
     * _Available since v4.1._
     */
    modifier onlyRole(bytes32 role) {
        _checkRole(role);
        _;
    }

    function __AccessControl_init() internal onlyInitializing {
    }

    function __AccessControl_init_unchained() internal onlyInitializing {
    }
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IAccessControlUpgradeable).interfaceId || super.supportsInterface(interfaceId);
    }

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view virtual override returns (bool) {
        return _roles[role].members[account];
    }

    /**
     * @dev Revert with a standard message if `_msgSender()` is missing `role`.
     * Overriding this function changes the behavior of the {onlyRole} modifier.
     *
     * Format of the revert message is described in {_checkRole}.
     *
     * _Available since v4.6._
     */
    function _checkRole(bytes32 role) internal view virtual {
        _checkRole(role, _msgSender());
    }

    /**
     * @dev Revert with a standard message if `account` is missing `role`.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     */
    function _checkRole(bytes32 role, address account) internal view virtual {
        if (!hasRole(role, account)) {
            revert(
                string(
                    abi.encodePacked(
                        "AccessControl: account ",
                        StringsUpgradeable.toHexString(account),
                        " is missing role ",
                        StringsUpgradeable.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view virtual override returns (bytes32) {
        return _roles[role].adminRole;
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     *
     * May emit a {RoleGranted} event.
     */
    function grantRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _grantRole(role, account);
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     *
     * May emit a {RoleRevoked} event.
     */
    function revokeRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _revokeRole(role, account);
    }

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been revoked `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     *
     * May emit a {RoleRevoked} event.
     */
    function renounceRole(bytes32 role, address account) public virtual override {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");

        _revokeRole(role, account);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * May emit a {RoleGranted} event.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     *
     * NOTE: This function is deprecated in favor of {_grantRole}.
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }

    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        bytes32 previousAdminRole = getRoleAdmin(role);
        _roles[role].adminRole = adminRole;
        emit RoleAdminChanged(role, previousAdminRole, adminRole);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * Internal function without access restriction.
     *
     * May emit a {RoleGranted} event.
     */
    function _grantRole(bytes32 role, address account) internal virtual {
        if (!hasRole(role, account)) {
            _roles[role].members[account] = true;
            emit RoleGranted(role, account, _msgSender());
        }
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * Internal function without access restriction.
     *
     * May emit a {RoleRevoked} event.
     */
    function _revokeRole(bytes32 role, address account) internal virtual {
        if (hasRole(role, account)) {
            _roles[role].members[account] = false;
            emit RoleRevoked(role, account, _msgSender());
        }
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[49] private __gap;
}
          

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {IERC165} from "@openzeppelin/contracts/interfaces/IERC165.sol";

interface IWFFTokenERC404 {

  error NotFound();
  error InvalidTokenId();
  error AlreadyExists();
  error InvalidOperator();
  error Unauthorized();
  error InsufficientAllowance();
  error InvalidApproval();
  error MintLimitReached();
  error InsufficientInactiveBalance();
  error ERC721InvalidSender(address);
  error ERC721InvalidReceiver(address);
  error IncorrectEthValue();
  error FailToSendEther();
  error ERC20InvalidSender(address);
  error ERC20InvalidReceiver(address);
  error ERC20InsufficientBalance(address, uint256, uint256);

  // function name() external view returns (string memory);
  // function symbol() external view returns (string memory);
  // function decimals() external view returns (uint8);
  // function totalSupply() external view returns (uint256);
  // function balanceOf(address owner_) external view returns (uint256);
  // function allowance(
  //   address owner_,
  //   address spender_
  // ) external view returns (uint256);
  // function transfer(address to_, uint256 amount_) external returns (bool);
  // function DOMAIN_SEPARATOR() external view returns (bytes32);
  // function permit(
  //   address owner_,
  //   address spender_,
  //   uint256 value_,
  //   uint256 deadline_,
  //   uint8 v_,
  //   bytes32 r_,
  //   bytes32 s_
  // ) external;
  function ownerOf(uint256 id_) external view returns (address erc721Owner);
  function safeTransferFrom(address from_, address to_, uint256 id_) external;
  function safeTransferFrom(
    address from_,
    address to_,
    uint256 id_,
    bytes calldata data_
  ) external;
  // function transferFrom(
  //   address from_,
  //   address to_,
  //   uint256 valueOrId_
  // ) external returns (bool);
  // function approve(
  //   address spender_,
  //   uint256 valueOrId_
  // ) external returns (bool);
  function setApprovalForAll(address operator_, bool approved_) external;
  function getApproved(uint256 _tokenId) external view returns (address);
  function isApprovedForAll(
    address owner_,
    address operator_
  ) external view returns (bool);
  function tokenURI(uint256 id_) external view returns (string memory);

  function inactiveBalance(address owner_) external view returns (uint256);
  function activeBalance(address owner_) external view returns (uint256);
  function erc721TotalSupply() external view returns (uint256);
  function erc721BalanceOf(address owner_) external view returns (uint256);
  function owned(address owner_) external view returns (uint256[] memory);
  function getERC721QueueLength() external view returns (uint256);
  function getERC721TokensInQueue(
    uint256 start_,
    uint256 count_
  ) external view returns (uint256[] memory);
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.4) (token/ERC20/extensions/IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 *
 * ==== Security Considerations
 *
 * There are two important considerations concerning the use of `permit`. The first is that a valid permit signature
 * expresses an allowance, and it should not be assumed to convey additional meaning. In particular, it should not be
 * considered as an intention to spend the allowance in any specific way. The second is that because permits have
 * built-in replay protection and can be submitted by anyone, they can be frontrun. A protocol that uses permits should
 * take this into consideration and allow a `permit` call to fail. Combining these two aspects, a pattern that may be
 * generally recommended is:
 *
 * ```solidity
 * function doThingWithPermit(..., uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) public {
 *     try token.permit(msg.sender, address(this), value, deadline, v, r, s) {} catch {}
 *     doThing(..., value);
 * }
 *
 * function doThing(..., uint256 value) public {
 *     token.safeTransferFrom(msg.sender, address(this), value);
 *     ...
 * }
 * ```
 *
 * Observe that: 1) `msg.sender` is used as the owner, leaving no ambiguity as to the signer intent, and 2) the use of
 * `try/catch` allows the permit to fail and makes the code tolerant to frontrunning. (See also
 * {SafeERC20-safeTransferFrom}).
 *
 * Additionally, note that smart contract wallets (such as Argent or Safe) are not able to produce permit signatures, so
 * contracts should have entry points that don't rely on permit.
 */
interface IERC20PermitUpgradeable {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     *
     * CAUTION: See Security Considerations above.
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}
          

pragma solidity >=0.6.2;

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}
          

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Immutable state
/// @notice Functions that return immutable state of the router
interface IPeripheryImmutableState {
    /// @return Returns the address of the Uniswap V3 factory
    function factory() external view returns (address);

    /// @return Returns the address of WETH9
    function WETH9() external view returns (address);
}
          

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

import "@openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC20/extensions/ERC20BurnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC20/extensions/ERC20PausableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/access/AccessControlUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC20/extensions/ERC20PermitUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/UUPSUpgradeable.sol";

contract WFFToken is Initializable, ERC20Upgradeable, ERC20BurnableUpgradeable, ERC20PausableUpgradeable, AccessControlUpgradeable, ERC20PermitUpgradeable, UUPSUpgradeable {
    bytes32 public constant PAUSER_ROLE = keccak256("PAUSER_ROLE");
    bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
    bytes32 public constant UPGRADER_ROLE = keccak256("UPGRADER_ROLE");

    /// @custom:oz-upgrades-unsafe-allow constructor
    constructor() {
        _disableInitializers();
    }

    function initialize(address defaultAdmin, address pauser, address minter, address upgrader)
        initializer public
    {
        __ERC20_init("wormsforfun", "WFF");
        __ERC20Burnable_init();
        __ERC20Pausable_init();
        __AccessControl_init();
        __ERC20Permit_init("wormsforfun");
        __UUPSUpgradeable_init();

        _grantRole(DEFAULT_ADMIN_ROLE, defaultAdmin);
        _grantRole(PAUSER_ROLE, pauser);
        _mint(msg.sender, 10000000000 * 10 ** decimals());
        _grantRole(MINTER_ROLE, minter);
        _grantRole(UPGRADER_ROLE, upgrader);
    }

    function pause() public onlyRole(PAUSER_ROLE) {
        _pause();
    }

    function unpause() public onlyRole(PAUSER_ROLE) {
        _unpause();
    }

    function mint(address to, uint256 amount) public virtual onlyRole(MINTER_ROLE) {
        _mint(to, amount);
    }

    function _authorizeUpgrade(address newImplementation)
        internal
        onlyRole(UPGRADER_ROLE)
        override
    {}

    // The following functions are overrides required by Solidity.

function _beforeTokenTransfer(address from, address to, uint256 amount)
        internal
        whenNotPaused
        override(ERC20Upgradeable, ERC20PausableUpgradeable)
    {
        super._beforeTokenTransfer(from, to, amount);
    }
}
          

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

library ERC20Events {
  event Approval(address indexed owner, address indexed spender, uint256 value);
  event Transfer(address indexed from, address indexed to, uint256 amount);
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;

import "./IERC165Upgradeable.sol";
import {Initializable} from "../../proxy/utils/Initializable.sol";

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165Upgradeable is Initializable, IERC165Upgradeable {
    function __ERC165_init() internal onlyInitializing {
    }

    function __ERC165_init_unchained() internal onlyInitializing {
    }
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165Upgradeable).interfaceId;
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/ERC20Pausable.sol)

pragma solidity ^0.8.0;

import "../ERC20Upgradeable.sol";
import "../../../security/PausableUpgradeable.sol";
import {Initializable} from "../../../proxy/utils/Initializable.sol";

/**
 * @dev ERC20 token with pausable token transfers, minting and burning.
 *
 * Useful for scenarios such as preventing trades until the end of an evaluation
 * period, or having an emergency switch for freezing all token transfers in the
 * event of a large bug.
 *
 * IMPORTANT: This contract does not include public pause and unpause functions. In
 * addition to inheriting this contract, you must define both functions, invoking the
 * {Pausable-_pause} and {Pausable-_unpause} internal functions, with appropriate
 * access control, e.g. using {AccessControl} or {Ownable}. Not doing so will
 * make the contract unpausable.
 */
abstract contract ERC20PausableUpgradeable is Initializable, ERC20Upgradeable, PausableUpgradeable {
    function __ERC20Pausable_init() internal onlyInitializing {
        __Pausable_init_unchained();
    }

    function __ERC20Pausable_init_unchained() internal onlyInitializing {
    }
    /**
     * @dev See {ERC20-_beforeTokenTransfer}.
     *
     * Requirements:
     *
     * - the contract must not be paused.
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual override {
        super._beforeTokenTransfer(from, to, amount);

        require(!paused(), "ERC20Pausable: token transfer while paused");
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (interfaces/IERC1967.sol)

pragma solidity ^0.8.0;

/**
 * @dev ERC-1967: Proxy Storage Slots. This interface contains the events defined in the ERC.
 *
 * _Available since v4.8.3._
 */
interface IERC1967Upgradeable {
    /**
     * @dev Emitted when the implementation is upgraded.
     */
    event Upgraded(address indexed implementation);

    /**
     * @dev Emitted when the admin account has changed.
     */
    event AdminChanged(address previousAdmin, address newAdmin);

    /**
     * @dev Emitted when the beacon is changed.
     */
    event BeaconUpgraded(address indexed beacon);
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 amount) external returns (bool);
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Counters.sol)

pragma solidity ^0.8.0;

/**
 * @title Counters
 * @author Matt Condon (@shrugs)
 * @dev Provides counters that can only be incremented, decremented or reset. This can be used e.g. to track the number
 * of elements in a mapping, issuing ERC721 ids, or counting request ids.
 *
 * Include with `using Counters for Counters.Counter;`
 */
library CountersUpgradeable {
    struct Counter {
        // This variable should never be directly accessed by users of the library: interactions must be restricted to
        // the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add
        // this feature: see https://github.com/ethereum/solidity/issues/4637
        uint256 _value; // default: 0
    }

    function current(Counter storage counter) internal view returns (uint256) {
        return counter._value;
    }

    function increment(Counter storage counter) internal {
        unchecked {
            counter._value += 1;
        }
    }

    function decrement(Counter storage counter) internal {
        uint256 value = counter._value;
        require(value > 0, "Counter: decrement overflow");
        unchecked {
            counter._value = value - 1;
        }
    }

    function reset(Counter storage counter) internal {
        counter._value = 0;
    }
}