// File: contracts/WallStreetWolves.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

/****************************************
 * @team:   GoldenX                     *
 ****************************************
 *   Blimpie-ERC721 provides low-gas    *
 *           mints + transfers          *
 ***************************************/

import "./Delegated.sol";
import "./PaymentSplitterMod.sol";
import "./ERC721Staked.sol";
import "./Verify.sol";
import "@openzeppelin/contracts/utils/Strings.sol";

interface IWSWFounders {
  function balanceOf(address _account, uint256 _id)
    external
    view
    returns (uint256);
}

contract WallStreetWolves is
  Delegated,
  ERC721Staked,
  Verify,
  PaymentSplitterMod
{
  using Strings for uint256;

  uint256 public MAX_SUPPLY = 10000;
  uint256 public PRICE = 0.5 ether;

  uint256 public CURRENT_ROUND = 1;
  uint256 public ROUND_SUPPLY = 2500;
  uint256 public ROUND_MINTED = 0;
  uint256 public PRESALE_QUANTITY = 2;
  uint256 public PUBLIC_QUANTITY = 20;

  mapping(address => uint256) private foundersQuantities;
  mapping(uint256 => mapping(address => uint256)) private presaleMinters;

  string private tokenURIPrefix;
  string private tokenURISuffix;

  address private teamAddress = 0x2d2352a56827515FAf6088c4cDf59befb4d0A67a;

  enum SaleState {
    paused,
    founders,
    presale,
    publicsale
  }

  SaleState public saleState = SaleState.paused;

  IWSWFounders public WSWFoundersProxy =
    IWSWFounders(0x48C8eC816F7789C2d4A517fca3D2fa33ac3Cc1c7);

  address[] private splitter = [
    0xed386149321FBd84f0c4e27a1701Ad05eCA32f8A,
    0x2d2352a56827515FAf6088c4cDf59befb4d0A67a,
    0x5B1DC9219786c7929B4684eF8301bdF4F1d67465
  ];
  uint256[] private splitterShares = [3, 85, 12];

  constructor(address _signer)
    ERC721B("Wall Street Wolves", "WSW", 0)
    PaymentSplitterMod(splitter, splitterShares)
  {
    setSigner(_signer);
  }

  //external payable
  fallback() external payable {}

  function airdrop(address _address, uint256 _quantity) public onlyDelegates {
    require(
      totalSupply() + _quantity <= MAX_SUPPLY,
      "airdrop: Invalid quantity."
    );
    for (uint256 i; i < _quantity; ++i) {
      mint1(_address);
    }
  }

  function mint(uint256 _quantity, bytes memory _signature) public payable {
    require(saleState != SaleState.paused, "mint: Sale paused");
    require(totalSupply() + _quantity <= MAX_SUPPLY, "mint: Invalid quantity.");

    if (saleState == SaleState.founders) {
      uint256 balance = WSWFoundersProxy.balanceOf(msg.sender, 0);
      require(
        balance >= _quantity + foundersQuantities[msg.sender],
        "mint: Invalid founders quantity"
      );
      foundersQuantities[msg.sender] += _quantity;
    } else if (saleState == SaleState.presale) {
      require(msg.value >= _quantity * PRICE, "mint: Incorrect ETH sent.");
      require(
        ROUND_MINTED + _quantity <= ROUND_SUPPLY,
        "mint: Invalid quantity"
      );
      require(
        _quantity + presaleMinters[CURRENT_ROUND][msg.sender] <=
          PRESALE_QUANTITY,
        "mint: Invalid quantity."
      );
      require(verify(_quantity, _signature), "mint: Not on presale list.");
      ROUND_MINTED += _quantity;
      presaleMinters[CURRENT_ROUND][msg.sender] += _quantity;
    } else if (saleState == SaleState.publicsale) {
      require(msg.value >= _quantity * PRICE, "mint: Incorrect ETH sent.");
      require(
        ROUND_MINTED + _quantity <= ROUND_SUPPLY,
        "mint: Invalid quantity"
      );
      require(_quantity <= PUBLIC_QUANTITY, "mint: Invalid quantity.");
      ROUND_MINTED += _quantity;
    }

    for (uint256 i; i < _quantity; ++i) {
      mint1(msg.sender);
    }
  }

  function resetRound(
    uint256 _roundSupply,
    uint256 _price,
    uint256 _airdropQuantity
  ) external onlyDelegates {
    ROUND_SUPPLY = _roundSupply;
    ROUND_MINTED = 0;
    PRICE = _price;
    saleState = SaleState.presale;
    CURRENT_ROUND += 1;

    if (_airdropQuantity > 0) {
      airdrop(teamAddress, _airdropQuantity);
    }
  }

  function setVariables(
    uint256 _maxSupply,
    uint256 _price,
    SaleState _saleState,
    uint256 _presaleQuantity,
    uint256 _publicQuantity
  ) external onlyDelegates {
    MAX_SUPPLY = _maxSupply;
    PRICE = _price;
    saleState = _saleState;
    PRESALE_QUANTITY = _presaleQuantity;
    PUBLIC_QUANTITY = _publicQuantity;
  }

  function setTeamAddress(address _newTeamAddress) external onlyDelegates {
    require(teamAddress != _newTeamAddress);
    teamAddress = _newTeamAddress;
  }

  function setSaleState(SaleState _newSaleState) external onlyDelegates {
    require(saleState != _newSaleState);
    saleState = _newSaleState;
  }

  function setWSWFoundersContract(address _wswFounders) external onlyDelegates {
    if (address(WSWFoundersProxy) != _wswFounders)
      WSWFoundersProxy = IWSWFounders(_wswFounders);
  }

  function setRarity(uint256[] memory _tokensToSet, uint8 rarity)
    external
    onlyDelegates
  {
    require(totalSupply() > _tokensToSet.length, "setRarity: invalid length");
    for (uint256 i; i < _tokensToSet.length; ++i) {
      tokens[_tokensToSet[i]].rarity = rarity;
    }
  }

  function setTokenURI(
    string memory _tokenURIPrefix,
    string memory _tokenURISuffix
  ) public onlyDelegates {
    tokenURIPrefix = _tokenURIPrefix;
    tokenURISuffix = _tokenURISuffix;
  }

  function tokenURI(uint256 _tokenId)
    external
    view
    override
    returns (string memory)
  {
    require(_exists(_tokenId), "tokenURI: Query for nonexistent token");
    return
      string(
        abi.encodePacked(tokenURIPrefix, _tokenId.toString(), tokenURISuffix)
      );
  }

  function mint1(address _to) internal {
    uint256 tokenId = _next();
    tokens.push(Token(_to, 1, 1));

    _safeMint(_to, tokenId, "");
  }

  function _mint(address _to, uint256 _tokenId) internal override {
    emit Transfer(address(0), _to, _tokenId);
  }
}

// File: contracts/Delegated.sol




// SPDX-License-Identifier: BSD-3-Clause

pragma solidity ^0.8.0;

/***********************
* @author: squeebo_nft *
************************/

import "@openzeppelin/contracts/access/Ownable.sol";

contract Delegated is Ownable{
  mapping(address => bool) internal _delegates;

  constructor(){
    _delegates[owner()] = true;
  }

  modifier onlyDelegates {
    require(_delegates[msg.sender], "Invalid delegate" );
    _;
  }

  //onlyOwner
  function isDelegate( address addr ) external view onlyOwner returns ( bool ){
    return _delegates[addr];
  }

  function setDelegate( address addr, bool isDelegate_ ) external onlyOwner{
    _delegates[addr] = isDelegate_;
  }

  function transferOwnership(address newOwner) public virtual override onlyOwner {
    _delegates[newOwner] = true;
    super.transferOwnership( newOwner );
  }
}
// File: contracts/PaymentSplitterMod.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/utils/Address.sol";
import "@openzeppelin/contracts/utils/Context.sol";

/**
 * @title PaymentSplitter
 * @dev This contract allows to split Ether payments among a group of accounts. The sender does not need to be aware
 * that the Ether will be split in this way, since it is handled transparently by the contract.
 *
 * The split can be in equal parts or in any other arbitrary proportion. The way this is specified is by assigning each
 * account to a number of shares. Of all the Ether that this contract receives, each account will then be able to claim
 * an amount proportional to the percentage of total shares they were assigned.
 *
 * `PaymentSplitter` follows a _pull payment_ model. This means that payments are not automatically forwarded to the
 * accounts but kept in this contract, and the actual transfer is triggered as a separate step by calling the {release}
 * function.
 */
contract PaymentSplitterMod is Context {
    event PayeeAdded(address account, uint256 shares);
    event PaymentReleased(address to, uint256 amount);
    event PaymentReceived(address from, uint256 amount);

    uint256 private _totalShares;
    uint256 private _totalReleased;

    mapping(address => uint256) private _shares;
    mapping(address => uint256) private _released;
    address[] private _payees;

    /**
     * @dev Creates an instance of `PaymentSplitter` where each account in `payees` is assigned the number of shares at
     * the matching position in the `shares` array.
     *
     * All addresses in `payees` must be non-zero. Both arrays must have the same non-zero length, and there must be no
     * duplicates in `payees`.
     */
    constructor(address[] memory payees, uint256[] memory shares_) payable {
        require(payees.length == shares_.length, "PaymentSplitter: payees and shares length mismatch");
        require(payees.length > 0, "PaymentSplitter: no payees");

        for (uint256 i = 0; i < payees.length; i++) {
            _addPayee(payees[i], shares_[i]);
        }
    }

    /**
     * @dev The Ether received will be logged with {PaymentReceived} events. Note that these events are not fully
     * reliable: it's possible for a contract to receive Ether without triggering this function. This only affects the
     * reliability of the events, and not the actual splitting of Ether.
     *
     * To learn more about this see the Solidity documentation for
     * https://solidity.readthedocs.io/en/latest/contracts.html#fallback-function[fallback
     * functions].
     */
    receive() external payable {
        emit PaymentReceived(_msgSender(), msg.value);
    }

    /**
     * @dev Getter for the total shares held by payees.
     */
    function totalShares() public view returns (uint256) {
        return _totalShares;
    }

    /**
     * @dev Getter for the total amount of Ether already released.
     */
    function totalReleased() public view returns (uint256) {
        return _totalReleased;
    }

    /**
     * @dev Getter for the amount of shares held by an account.
     */
    function shares(address account) public view returns (uint256) {
        return _shares[account];
    }

    /**
     * @dev Getter for the amount of Ether already released to a payee.
     */
    function released(address account) public view returns (uint256) {
        return _released[account];
    }

    /**
     * @dev Getter for the address of the payee number `index`.
     */
    function payee(uint256 index) public view returns (address) {
        return _payees[index];
    }

    /**
     * @dev Triggers a transfer to `account` of the amount of Ether they are owed, according to their percentage of the
     * total shares and their previous withdrawals.
     */
    function release(address payable account) public virtual {
        require(_shares[account] > 0, "PaymentSplitter: account has no shares");

        uint256 totalReceived = address(this).balance + _totalReleased;
        uint256 payment = (totalReceived * _shares[account]) / _totalShares - _released[account];
        require(payment != 0, "PaymentSplitter: account is not due payment");

        _released[account] = _released[account] + payment;
        _totalReleased = _totalReleased + payment;

        Address.sendValue(account, payment);
        emit PaymentReleased(account, payment);
    }

    function _addPayee(address account, uint256 shares_) internal {
        require(account != address(0), "PaymentSplitter: account is the zero address");
        require(shares_ > 0, "PaymentSplitter: shares are 0");
        require(_shares[account] == 0, "PaymentSplitter: account already has shares");

        _payees.push(account);
        _shares[account] = shares_;
        _totalShares = _totalShares + shares_;
        emit PayeeAdded(account, shares_);
    }

    function _resetCounters() internal {
        _totalReleased = 0;
        for(uint i; i < _payees.length; ++i ){
            _released[ _payees[i] ] = 0;
        }
    }

    function _setPayee( uint index, address account, uint newShares ) internal {
        _totalShares = _totalShares - _shares[ account ] + newShares;
        _shares[ account ] = newShares;
        _payees[ index ] = account;
    }
}
// File: contracts/ERC721Staked.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

import "@openzeppelin/contracts/utils/Strings.sol";
import "./Delegated.sol";
import "./ERC721Batch.sol";
import "./IERC20Proxy.sol";

abstract contract ERC721Staked is Delegated, ERC721Batch {
  using Strings for uint256;

  struct StakeConfig {
    address coinContract;
    uint256 stakePeriod;
    uint256 stakeReward;
  }

  StakeConfig public stakeConfig;

  mapping(uint8 => uint256) public rarityMultiplier;

  function setRarityMultiplier(uint8 _rarity, uint256 _multiplier)
    external
    onlyDelegates
  {
    rarityMultiplier[_rarity] = _multiplier;
  }

  function claimTokens(uint256[] calldata tokenIds, bool restake) external {
    uint256 coinQuantity;
    uint32 time = uint32(block.timestamp);
    for (uint256 i; i < tokenIds.length; ++i) {
      require(_exists(tokenIds[i]), "claim for nonexistent token");

      Token storage token = tokens[tokenIds[i]];
      require(token.owner == msg.sender, "caller is not owner");
      require(
        token.stakeDate > 1,
        string(
          abi.encodePacked("token ", tokenIds[i].toString(), " is not staked")
        )
      );
      uint256 baseQuantity = ((time - token.stakeDate) *
        stakeConfig.stakeReward) / stakeConfig.stakePeriod;

      coinQuantity += baseQuantity * rarityMultiplier[token.rarity];

      if (restake) token.stakeDate = time;
      else token.stakeDate = 1;
    }

    IERC20Proxy(stakeConfig.coinContract).mintTo(msg.sender, coinQuantity);
  }

  function stakeTokens(uint256[] calldata tokenIds) external {
    for (uint256 i; i < tokenIds.length; ++i) {
      require(_exists(tokenIds[i]), "stake for nonexistent token");

      Token storage token = tokens[tokenIds[i]];
      require(token.owner == msg.sender, "caller is not owner");
      require(
        token.stakeDate < 2,
        string(
          abi.encodePacked(
            "token ",
            tokenIds[i].toString(),
            " is already staked"
          )
        )
      );
      tokens[tokenIds[i]].stakeDate = uint32(block.timestamp);
    }
  }

  //delegated
  function setStakeConfig(StakeConfig calldata stakeConfig_)
    external
    onlyDelegates
  {
    stakeConfig = stakeConfig_;
  }

  //internal
  function _isStaked(uint256 tokenId) internal view virtual returns (bool) {
    return tokens[tokenId].stakeDate > 1;
  }

  function _transfer(
    address from,
    address to,
    uint256 tokenId
  ) internal virtual override {
    require(!_isStaked(tokenId), "token is staked");
    super._transfer(from, to, tokenId);
  }
}

// File: contracts/Verify.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

import "./Delegated.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";

contract Verify is Delegated {
    using Strings for uint;
    using ECDSA for bytes32;

    address private signer;
    
    function verify( uint _quantity,  bytes memory _signature ) internal view returns ( bool ) {
        address signerCheck = getAddressSigner( _quantity.toString(), _signature );
        return signerCheck == signer;
    }

    function getAddressSigner( string memory _quantity, bytes memory _signature ) private view returns ( address ) {
        bytes32 hash = createHash( _quantity );
        return hash.toEthSignedMessageHash().recover( _signature );
    }

    function createHash( string memory _quantity ) private view returns ( bytes32 ) {
        return keccak256( abi.encodePacked( address(this), msg.sender, _quantity ) );
    }
    
    function setSigner( address _signer ) public onlyOwner{
        signer = _signer;
    }
}

// File: @openzeppelin/contracts/utils/Strings.sol



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

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**
     * @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] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol



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

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/utils/Context.sol



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

pragma solidity ^0.8.0;

/**
 * @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 Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

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

// File: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @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
     * ====
     *
     * [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://diligence.consensys.net/posts/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/v0.5.11/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 functionCall(target, data, "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");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(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) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(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) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason 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 {
            // 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

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: contracts/ERC721Batch.sol




// SPDX-License-Identifier: BSD-3-Clause

pragma solidity ^0.8.0;

/****************************************
 * @author: squeebo_nft                 *
 ****************************************
 *   Blimpie-FF721 provides low-gas     *
 *       mints + transfers              *
 ****************************************/

import "./IERC721Batch.sol";
import "./ERC721EnumerableB.sol";

abstract contract ERC721Batch is ERC721EnumerableB, IERC721Batch {
  function isOwnerOf( address account, uint[] calldata tokenIds ) external view override returns( bool ){
    for(uint i; i < tokenIds.length; ++i ){
      if( account != tokens[ tokenIds[i] ].owner )
        return false;
    }

    return true;
  }

  function transferBatch( address from, address to, uint[] calldata tokenIds, bytes calldata data ) external override{
    for(uint i; i < tokenIds.length; ++i ){
      safeTransferFrom( from, to, tokenIds[i], data );
    }
  }

  function walletOfOwner( address account ) external view override returns( uint[] memory wallet ){
    uint count;
    uint quantity = balanceOf( account );
    wallet = new uint[]( quantity );
    for( uint i; i < tokens.length; ++i ){
      if( account == tokens[i].owner ){
        wallet[ count++ ] = i;
        if( count == quantity )
          break;
      }
    }
    return wallet;
  }
}
// File: contracts/IERC20Proxy.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

interface IERC20Proxy is IERC20 {
  function burnFrom( address account, uint256 amount ) external;
  function mintTo( address account, uint256 amount ) external;
}
// File: contracts/IERC721Batch.sol



// SPDX-License-Identifier: BSD-3-Clause

pragma solidity ^0.8.0;

interface IERC721Batch {
  function isOwnerOf( address account, uint[] calldata tokenIds ) external view returns( bool );
  function transferBatch( address from, address to, uint[] calldata tokenIds, bytes calldata data ) external;
  function walletOfOwner( address account ) external view returns( uint[] memory );
}
// File: contracts/ERC721EnumerableB.sol



// SPDX-License-Identifier: BSD-3-Clause

pragma solidity ^0.8.0;

/****************************************
 * @author: squeebo_nft                 *
 ****************************************
 *   Blimpie-ERC721 provides low-gas    *
 *       mints + transfers              *
 ****************************************/

import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol";
import "./ERC721B.sol";

abstract contract ERC721EnumerableB is ERC721B, IERC721Enumerable {
  function supportsInterface( bytes4 interfaceId ) public view virtual override(IERC165, ERC721B) returns( bool isSupported ){
    return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);
  }

  function tokenOfOwnerByIndex( address owner, uint index ) external view override returns( uint tokenId ){
    uint count;
    for( uint i; i < tokens.length; ++i ){
      if( owner == tokens[i].owner ){
        if( count == index )
          return i;
        else
          ++count;
      }
    }

    revert("ERC721EnumerableB: owner index out of bounds");
  }

  function tokenByIndex( uint index ) external view override returns( uint tokenId ){
    require( index < totalSupply(), "ERC721EnumerableB: query for nonexistent token");
    return index + _offset;
  }

  function totalSupply() public view override( ERC721B, IERC721Enumerable ) returns( uint ){
    return ERC721B.totalSupply();
  }
}
// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC721/extensions/IERC721Enumerable.sol)

pragma solidity ^0.8.0;

import "../IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {
    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256);

    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256);
}

// File: contracts/ERC721B.sol



// SPDX-License-Identifier: BSD-3-Clause

pragma solidity ^0.8.0;

/****************************************
 *   Blimpie-FF721 provides low-gas  *
 *     mints + transfers        *
 ****************************************/

import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "@openzeppelin/contracts/utils/Context.sol";
import "@openzeppelin/contracts/utils/introspection/ERC165.sol";

abstract contract ERC721B is Context, ERC165, IERC721, IERC721Metadata {
  using Address for address;

  struct Token {
    address owner;
    uint32 stakeDate;
    uint8 rarity;
  }

  Token[] public tokens;

  uint256 internal _burned;
  uint256 internal _offset;
  string private _name;
  string private _symbol;

  mapping(uint256 => address) internal _tokenApprovals;
  mapping(address => mapping(address => bool)) private _operatorApprovals;

  constructor(
    string memory name_,
    string memory symbol_,
    uint256 offset_
  ) {
    _name = name_;
    _symbol = symbol_;

    _offset = offset_;
    for (uint256 i; i < _offset; ++i) {
      tokens.push();
    }
  }

  function balanceOf(address owner) public view override returns (uint256) {
    require(owner != address(0), "Query for null address");
    uint256 balance = 0;
    for (uint256 i; i < tokens.length; ++i) {
      if (owner == tokens[i].owner) {
        ++balance;
      }
    }
    return balance;
  }

  function name() external view override returns (string memory name_) {
    return _name;
  }

  function ownerOf(uint256 tokenId)
    public
    view
    override
    returns (address owner)
  {
    require(_exists(tokenId), "ERC721B: query for nonexistent token");
    return tokens[tokenId].owner;
  }

  function supportsInterface(bytes4 interfaceId)
    public
    view
    virtual
    override(ERC165, IERC165)
    returns (bool isSupported)
  {
    return
      interfaceId == type(IERC721).interfaceId ||
      interfaceId == type(IERC721Metadata).interfaceId ||
      super.supportsInterface(interfaceId);
  }

  function symbol() external view override returns (string memory symbol_) {
    return _symbol;
  }

  function totalSupply() public view virtual returns (uint256) {
    return tokens.length - (_burned + _offset);
  }

  //approvals
  function approve(address to, uint256 tokenId) external override {
    address owner = ownerOf(tokenId);
    require(to != owner, "ERC721B: approval to current owner");

    require(
      _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
      "ERC721B: caller is not owner nor approved for all"
    );

    _approve(to, tokenId);
  }

  function getApproved(uint256 tokenId)
    public
    view
    override
    returns (address approver)
  {
    require(_exists(tokenId), "ERC721: query for nonexistent token");
    return _tokenApprovals[tokenId];
  }

  function isApprovedForAll(address owner, address operator)
    public
    view
    override
    returns (bool isApproved)
  {
    return _operatorApprovals[owner][operator];
  }

  function setApprovalForAll(address operator, bool approved)
    external
    override
  {
    _operatorApprovals[_msgSender()][operator] = approved;
    emit ApprovalForAll(_msgSender(), operator, approved);
  }

  //transfers
  function safeTransferFrom(
    address from,
    address to,
    uint256 tokenId
  ) external override {
    safeTransferFrom(from, to, tokenId, "");
  }

  function safeTransferFrom(
    address from,
    address to,
    uint256 tokenId,
    bytes memory _data
  ) public override {
    require(
      _isApprovedOrOwner(_msgSender(), tokenId),
      "ERC721B: caller is not owner nor approved"
    );
    _safeTransfer(from, to, tokenId, _data);
  }

  function transferFrom(
    address from,
    address to,
    uint256 tokenId
  ) external override {
    //solhint-disable-next-line max-line-length
    require(
      _isApprovedOrOwner(_msgSender(), tokenId),
      "ERC721B: caller is not owner nor approved"
    );
    _transfer(from, to, tokenId);
  }

  //internal
  function _approve(address to, uint256 tokenId) internal {
    _tokenApprovals[tokenId] = to;
    emit Approval(ownerOf(tokenId), to, tokenId);
  }

  function _burn(uint256 tokenId) internal {
    address owner = ownerOf(tokenId);

    // Clear approvals
    _approve(address(0), tokenId);
    tokens[tokenId].owner = address(0);

    emit Transfer(owner, address(0), tokenId);
  }

  function _checkOnERC721Received(
    address from,
    address to,
    uint256 tokenId,
    bytes memory _data
  ) private returns (bool) {
    if (to.isContract()) {
      try
        IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data)
      returns (bytes4 retval) {
        return retval == IERC721Receiver.onERC721Received.selector;
      } catch (bytes memory reason) {
        if (reason.length == 0) {
          revert("ERC721B: transfer to non ERC721Receiver implementer");
        } else {
          assembly {
            revert(add(32, reason), mload(reason))
          }
        }
      }
    } else {
      return true;
    }
  }

  function _exists(uint256 tokenId) internal view returns (bool) {
    return tokenId < tokens.length && tokens[tokenId].owner != address(0);
  }

  function _isApprovedOrOwner(address spender, uint256 tokenId)
    internal
    view
    returns (bool isApproved)
  {
    require(_exists(tokenId), "ERC721B: query for nonexistent token");
    address owner = ownerOf(tokenId);
    return (spender == owner ||
      getApproved(tokenId) == spender ||
      isApprovedForAll(owner, spender));
  }

  function _mint(address to, uint256 tokenId) internal virtual;

  function _next() internal view virtual returns (uint256) {
    return tokens.length + _offset;
  }

  function _safeMint(address to, uint256 tokenId) internal {
    _safeMint(to, tokenId, "");
  }

  function _safeMint(
    address to,
    uint256 tokenId,
    bytes memory _data
  ) internal {
    _mint(to, tokenId);
    require(
      _checkOnERC721Received(address(0), to, tokenId, _data),
      "ERC721B: transfer to non ERC721Receiver implementer"
    );
  }

  function _safeTransfer(
    address from,
    address to,
    uint256 tokenId,
    bytes memory _data
  ) internal {
    _transfer(from, to, tokenId);
    require(
      _checkOnERC721Received(from, to, tokenId, _data),
      "ERC721B: transfer to non ERC721Receiver implementer"
    );
  }

  function _transfer(
    address from,
    address to,
    uint256 tokenId
  ) internal virtual {
    require(
      ownerOf(tokenId) == from,
      "ERC721B: transfer of token that is not own"
    );

    // Clear approvals from the previous owner
    _approve(address(0), tokenId);
    tokens[tokenId].owner = to;

    emit Transfer(from, to, tokenId);
  }
}

// File: @openzeppelin/contracts/token/ERC721/IERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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`, 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 be 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: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * 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 Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @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 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);

    /**
     * @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;
}

// File: @openzeppelin/contracts/utils/introspection/IERC165.sol



// 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);
}

// File: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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 `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol



// 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);
}

// File: @openzeppelin/contracts/utils/introspection/ERC165.sol



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

pragma solidity ^0.8.0;

import "./IERC165.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 ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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);

    /**
     * @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);
}

// File: @openzeppelin/contracts/utils/cryptography/ECDSA.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/cryptography/ECDSA.sol)

pragma solidity ^0.8.0;

import "../Strings.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 ECDSA {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS,
        InvalidSignatureV
    }

    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");
        } else if (error == RecoverError.InvalidSignatureV) {
            revert("ECDSA: invalid signature 'v' 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) {
        // Check the signature length
        // - case 65: r,s,v signature (standard)
        // - case 64: r,vs signature (cf https://eips.ethereum.org/EIPS/eip-2098) _Available since v4.1._
        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.
            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 if (signature.length == 64) {
            bytes32 r;
            bytes32 vs;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            assembly {
                r := mload(add(signature, 0x20))
                vs := mload(add(signature, 0x40))
            }
            return tryRecover(hash, r, vs);
        } 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 (v != 27 && v != 28) {
            return (address(0), RecoverError.InvalidSignatureV);
        }

        // 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) {
        // 32 is the length in bytes of hash,
        // enforced by the type signature above
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
    }

    /**
     * @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", Strings.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) {
        return keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));
    }
}