// File: contracts/others/WPTNftStaking.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

/**
 * @author Brewlabs
 * This contract has been developed by brewlabs.info
 */
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

contract WPTNftStaking is Ownable, IERC721Receiver, ReentrancyGuard {
  using SafeERC20 for IERC20;

  bytes4 private constant _ERC721_RECEIVED = 0x150b7a02;
  uint256 private constant BLOCKS_PER_DAY = 6426;
  uint256 private PRECISION_FACTOR;

  // Whether it is initialized
  bool public isInitialized;
  uint256 public duration = 365; // 365 days

  // The block number when staking starts.
  uint256 public startBlock;
  // The block number when staking ends.
  uint256 public bonusEndBlock;
  // tokens created per block.
  uint256 public rewardPerBlock;
  // The block number of the last pool update
  uint256 public lastRewardBlock;

  address public treasury = 0xf91AfC2c104d040c5FCcDA625d038b09AE407019;
  uint256 public performanceFee = 0.00089 ether;

  // The staked token
  IERC721 public stakingNft;
  // The earned token
  IERC20 public earnedToken;
  // Accrued token per share
  uint256 public accTokenPerShare;
  uint256 public oneTimeLimit = 40;

  uint256 public totalStaked;
  uint256 private totalEarned;
  uint256 private paidRewards;
  uint256 private shouldTotalPaid;

  struct UserInfo {
    uint256 amount; // number of staked NFTs
    uint256[] tokenIds; // staked tokenIds
    uint256 rewardDebt; // Reward debt
  }
  // Info of each user that stakes tokenIds
  mapping(address => UserInfo) public userInfo;

  event Deposit(address indexed user, uint256[] tokenIds);
  event Withdraw(address indexed user, uint256[] tokenIds);
  event Claim(address indexed user, uint256 amount);
  event EmergencyWithdraw(address indexed user, uint256[] tokenIds);
  event AdminTokenRecovered(address tokenRecovered, uint256 amount);

  event NewStartAndEndBlocks(uint256 startBlock, uint256 endBlock);
  event NewRewardPerBlock(uint256 rewardPerBlock);
  event RewardsStop(uint256 blockNumber);
  event EndBlockUpdated(uint256 blockNumber);

  event ServiceInfoUpadted(address _addr, uint256 _fee);
  event DurationUpdated(uint256 _duration);

  constructor() {}

  /*
   * @notice Initialize the contract
   * @param _stakingNft: nft address to stake
   * @param _earnedToken: earned token address
   * @param _rewardPerBlock: reward per block (in earnedToken)
   */
  function initialize(
    IERC721 _stakingNft,
    IERC20 _earnedToken,
    uint256 _rewardPerBlock
  ) external onlyOwner {
    require(!isInitialized, "Already initialized");

    // Make this contract initialized
    isInitialized = true;

    stakingNft = _stakingNft;
    earnedToken = _earnedToken;
    rewardPerBlock = _rewardPerBlock;

    uint256 decimalsRewardToken = uint256(IERC20Metadata(address(earnedToken)).decimals());
    require(decimalsRewardToken < 30, "Must be inferior to 30");
    PRECISION_FACTOR = uint256(10**(40 - decimalsRewardToken));
  }

  /*
   * @notice Deposit staked tokens and collect reward tokens (if any)
   * @param _amount: amount to withdraw (in earnedToken)
   */
  function deposit(uint256[] memory _tokenIds) external payable nonReentrant {
    require(startBlock > 0 && startBlock < block.number, "Staking hasn't started yet");
    require(_tokenIds.length > 0, "must add at least one tokenId");
    require(_tokenIds.length <= oneTimeLimit, "cannot exceed one-time limit");

    _transferPerformanceFee();
    _updatePool();

    UserInfo storage user = userInfo[msg.sender];
    if (user.amount > 0) {
      uint256 pending = (user.amount * accTokenPerShare) / PRECISION_FACTOR - user.rewardDebt;
      if (pending > 0) {
        require(availableRewardTokens() >= pending, "Insufficient reward tokens");
        earnedToken.safeTransfer(address(msg.sender), pending);
        paidRewards += pending;
        emit Claim(msg.sender, pending);
      }
    }

    for (uint256 i = 0; i < _tokenIds.length; i++) {
      uint256 tokenId = _tokenIds[i];
      stakingNft.safeTransferFrom(msg.sender, address(this), tokenId);
      user.tokenIds.push(tokenId);
    }
    user.amount = user.amount + _tokenIds.length;
    user.rewardDebt = (user.amount * accTokenPerShare) / PRECISION_FACTOR;

    totalStaked = totalStaked + _tokenIds.length;
    emit Deposit(msg.sender, _tokenIds);
  }

  /*
   * @notice Withdraw staked tokenIds and collect reward tokens
   * @param _amount: number of tokenIds to unstake
   */
  function withdraw(uint256 _amount) external payable nonReentrant {
    require(_amount > 0, "Amount should be greator than 0");
    require(_amount <= oneTimeLimit, "cannot exceed one-time limit");

    UserInfo storage user = userInfo[msg.sender];
    require(user.amount >= _amount, "Amount to withdraw too high");

    _transferPerformanceFee();
    _updatePool();

    if (user.amount > 0) {
      uint256 pending = (user.amount * accTokenPerShare) / PRECISION_FACTOR - user.rewardDebt;
      if (pending > 0) {
        require(availableRewardTokens() >= pending, "Insufficient reward tokens");
        earnedToken.safeTransfer(address(msg.sender), pending);
        paidRewards += pending;
        emit Claim(msg.sender, pending);
      }
    }

    uint256[] memory _tokenIds = new uint256[](_amount);
    for (uint256 i = 0; i < _amount; i++) {
      uint256 tokenId = user.tokenIds[user.tokenIds.length - 1];
      user.tokenIds.pop();

      _tokenIds[i] = tokenId;
      stakingNft.safeTransferFrom(address(this), msg.sender, tokenId);
    }
    user.amount = user.amount - _amount;
    user.rewardDebt = (user.amount * accTokenPerShare) / PRECISION_FACTOR;

    totalStaked = totalStaked - _amount;
    emit Withdraw(msg.sender, _tokenIds);
  }

  function claimReward() external payable nonReentrant {
    UserInfo storage user = userInfo[msg.sender];

    _transferPerformanceFee();
    _updatePool();

    if (user.amount == 0) return;

    uint256 pending = (user.amount * accTokenPerShare) / PRECISION_FACTOR - user.rewardDebt;
    if (pending > 0) {
      require(availableRewardTokens() >= pending, "Insufficient reward tokens");
      earnedToken.safeTransfer(address(msg.sender), pending);
      paidRewards += pending;
    }

    user.rewardDebt = (user.amount * accTokenPerShare) / PRECISION_FACTOR;
    emit Claim(msg.sender, pending);
  }

  /*
   * @notice Withdraw staked NFTs without caring about rewards
   * @dev Needs to be for emergency.
   */
  function emergencyWithdraw() external nonReentrant {
    UserInfo storage user = userInfo[msg.sender];
    uint256 _amount = user.amount;
    if (_amount > oneTimeLimit) _amount = oneTimeLimit;

    uint256[] memory _tokenIds = new uint256[](_amount);
    for (uint256 i = 0; i < _amount; i++) {
      uint256 tokenId = user.tokenIds[user.tokenIds.length - 1];
      user.tokenIds.pop();

      _tokenIds[i] = tokenId;
      stakingNft.safeTransferFrom(address(this), msg.sender, tokenId);
    }
    user.amount = user.amount - _amount;
    user.rewardDebt = (user.amount * accTokenPerShare) / PRECISION_FACTOR;
    totalStaked = totalStaked - _amount;

    emit EmergencyWithdraw(msg.sender, _tokenIds);
  }

  function stakedInfo(address _user) external view returns (uint256, uint256[] memory) {
    return (userInfo[_user].amount, userInfo[_user].tokenIds);
  }

  /**
   * @notice Available amount of reward token
   */
  function availableRewardTokens() public view returns (uint256) {
    return earnedToken.balanceOf(address(this));
  }

  function insufficientRewards() external view returns (uint256) {
    uint256 adjustedShouldTotalPaid = shouldTotalPaid;
    uint256 remainRewards = availableRewardTokens() + paidRewards;

    if (startBlock == 0) {
      adjustedShouldTotalPaid += rewardPerBlock * duration * BLOCKS_PER_DAY;
    } else {
      uint256 remainBlocks = _getMultiplier(lastRewardBlock, bonusEndBlock);
      adjustedShouldTotalPaid += rewardPerBlock * remainBlocks;
    }

    if (remainRewards >= adjustedShouldTotalPaid) return 0;
    return adjustedShouldTotalPaid - remainRewards;
  }

  /*
   * @notice View function to see pending reward on frontend.
   * @param _user: user address
   * @return Pending reward for a given user
   */
  function pendingReward(address _user) external view returns (uint256) {
    UserInfo storage user = userInfo[_user];

    uint256 adjustedTokenPerShare = accTokenPerShare;
    if (block.number > lastRewardBlock && totalStaked != 0 && lastRewardBlock > 0) {
      uint256 multiplier = _getMultiplier(lastRewardBlock, block.number);
      uint256 rewards = multiplier * rewardPerBlock;

      adjustedTokenPerShare += (rewards * PRECISION_FACTOR) / totalStaked;
    }

    return (user.amount * adjustedTokenPerShare) / PRECISION_FACTOR - user.rewardDebt;
  }

  /************************
   ** Admin Methods
   *************************/
  function increaseEmissionRate(uint256 _amount) external onlyOwner {
    require(startBlock > 0, "pool is not started");
    require(bonusEndBlock > block.number, "pool was already finished");
    require(_amount > 0, "invalid amount");

    _updatePool();
    earnedToken.safeTransferFrom(msg.sender, address(this), _amount);

    uint256 remainRewards = availableRewardTokens() + paidRewards;
    if (remainRewards > shouldTotalPaid) {
      remainRewards = remainRewards - shouldTotalPaid;

      uint256 remainBlocks = bonusEndBlock - block.number;
      rewardPerBlock = remainRewards / remainBlocks;
      emit NewRewardPerBlock(rewardPerBlock);
    }
  }

  /*
   * @notice Withdraw reward token
   * @dev Only callable by owner. Needs to be for emergency.
   */
  function emergencyRewardWithdraw(uint256 _amount) external onlyOwner {
    require(block.number > bonusEndBlock, "Pool is running");
    require(availableRewardTokens() >= _amount, "Insufficient reward tokens");

    if (_amount == 0) _amount = availableRewardTokens();
    earnedToken.safeTransfer(address(msg.sender), _amount);
  }

  function startReward() external onlyOwner {
    require(startBlock == 0, "Pool was already started");

    startBlock = block.number + 100;
    bonusEndBlock = startBlock + duration * BLOCKS_PER_DAY;
    lastRewardBlock = startBlock;

    emit NewStartAndEndBlocks(startBlock, bonusEndBlock);
  }

  function stopReward() external onlyOwner {
    _updatePool();

    uint256 remainRewards = availableRewardTokens() + paidRewards;
    if (remainRewards > shouldTotalPaid) {
      remainRewards = remainRewards - shouldTotalPaid;
      earnedToken.transfer(msg.sender, remainRewards);
    }

    bonusEndBlock = block.number;
    emit RewardsStop(bonusEndBlock);
  }

  function updateEndBlock(uint256 _endBlock) external onlyOwner {
    require(startBlock > 0, "Pool is not started");
    require(bonusEndBlock > block.number, "Pool was already finished");
    require(_endBlock > block.number && _endBlock > startBlock, "Invalid end block");

    bonusEndBlock = _endBlock;
    emit EndBlockUpdated(_endBlock);
  }

  /*
   * @notice Update reward per block
   * @dev Only callable by owner.
   * @param _rewardPerBlock: the reward per block
   */
  function updateRewardPerBlock(uint256 _rewardPerBlock) external onlyOwner {
    rewardPerBlock = _rewardPerBlock;
    emit NewRewardPerBlock(_rewardPerBlock);
  }

  function setDuration(uint256 _duration) external onlyOwner {
    require(_duration >= 30, "lower limit reached");

    duration = _duration;
    if (startBlock > 0) {
      bonusEndBlock = startBlock + duration * BLOCKS_PER_DAY;
      require(bonusEndBlock > block.number, "invalid duration");
    }
    emit DurationUpdated(_duration);
  }

  function setServiceInfo(address _treasury, uint256 _fee) external {
    require(msg.sender == treasury, "setServiceInfo: FORBIDDEN");
    require(_treasury != address(0x0), "Invalid address");

    treasury = _treasury;
    performanceFee = _fee;
    emit ServiceInfoUpadted(_treasury, _fee);
  }

  /**
   * @notice It allows the admin to recover wrong tokens sent to the contract
   * @param _token: the address of the token to withdraw
   * @dev This function is only callable by admin.
   */
  function rescueTokens(address _token) external onlyOwner {
    require(_token != address(earnedToken), "Cannot be reward token");

    uint256 amount = address(this).balance;
    if (_token == address(0x0)) {
      payable(msg.sender).transfer(amount);
    } else {
      amount = IERC20(_token).balanceOf(address(this));
      IERC20(_token).safeTransfer(address(msg.sender), amount);
    }

    emit AdminTokenRecovered(_token, amount);
  }

  /************************
   ** Internal Methods
   *************************/
  /*
   * @notice Update reward variables of the given pool to be up-to-date.
   */
  function _updatePool() internal {
    if (block.number <= lastRewardBlock || lastRewardBlock == 0) return;
    if (totalStaked == 0) {
      lastRewardBlock = block.number;
      return;
    }

    uint256 multiplier = _getMultiplier(lastRewardBlock, block.number);
    uint256 _reward = multiplier * rewardPerBlock;
    accTokenPerShare += (_reward * PRECISION_FACTOR) / totalStaked;
    lastRewardBlock = block.number;

    shouldTotalPaid += _reward;
  }

  /*
   * @notice Return reward multiplier over the given _from to _to block.
   * @param _from: block to start
   * @param _to: block to finish
   */
  function _getMultiplier(uint256 _from, uint256 _to) internal view returns (uint256) {
    if (_to <= bonusEndBlock) {
      return _to - _from;
    } else if (_from >= bonusEndBlock) {
      return 0;
    } else {
      return bonusEndBlock - _from;
    }
  }

  function _transferPerformanceFee() internal {
    require(msg.value >= performanceFee, "should pay small gas to compound or harvest");

    payable(treasury).transfer(performanceFee);
    if (msg.value > performanceFee) {
      payable(msg.sender).transfer(msg.value - performanceFee);
    }
  }

  /**
   * onERC721Received(address operator, address from, uint256 tokenId, bytes data) → bytes4
   * 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.
   */
  function onERC721Received(
    address,
    address,
    uint256,
    bytes calldata
  ) external view override returns (bytes4) {
    require(msg.sender == address(stakingNft), "not enabled NFT");
    return _ERC721_RECEIVED;
  }

  receive() external payable {}
}

// 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/security/ReentrancyGuard.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol



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

pragma solidity ^0.8.0;

import "../IERC20.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @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);
}

// 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/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/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// 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/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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 `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, 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 `sender` to `recipient` 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 sender,
        address recipient,
        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/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/utils/Address.sol



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

pragma solidity ^0.8.0;

/**
 * @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
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 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);
            }
        }
    }
}