//SPDX-License-Identifier: MIT


// File: @openzeppelin/contracts/utils/Strings.sol


// OpenZeppelin Contracts (last updated v4.7.0) (utils/Strings.sol)

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
    uint8 private constant _ADDRESS_LENGTH = 20;

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // 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);
    }

    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
    }
}

// File: @openzeppelin/contracts/security/ReentrancyGuard.sol


// 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/utils/Context.sol


// 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/security/Pausable.sol


// OpenZeppelin Contracts (last updated v4.7.0) (security/Pausable.sol)

pragma solidity ^0.8.0;


/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract Pausable is Context {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    constructor() {
        _paused = false;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        _requireNotPaused();
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        _requirePaused();
        _;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Throws if the contract is paused.
     */
    function _requireNotPaused() internal view virtual {
        require(!paused(), "Pausable: paused");
    }

    /**
     * @dev Throws if the contract is not paused.
     */
    function _requirePaused() internal view virtual {
        require(paused(), "Pausable: not paused");
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol


// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;


/**
 * @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 Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        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/token/ERC721/IERC721Receiver.sol


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// File: @openzeppelin/contracts/token/ERC721/utils/ERC721Holder.sol


// OpenZeppelin Contracts v4.4.1 (token/ERC721/utils/ERC721Holder.sol)

pragma solidity ^0.8.0;


/**
 * @dev Implementation of the {IERC721Receiver} interface.
 *
 * Accepts all token transfers.
 * Make sure the contract is able to use its token with {IERC721-safeTransferFrom}, {IERC721-approve} or {IERC721-setApprovalForAll}.
 */
contract ERC721Holder is IERC721Receiver {
    /**
     * @dev See {IERC721Receiver-onERC721Received}.
     *
     * Always returns `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address,
        address,
        uint256,
        bytes memory
    ) public virtual override returns (bytes4) {
        return this.onERC721Received.selector;
    }
}

// File: @openzeppelin/contracts/utils/Address.sol


// OpenZeppelin Contracts (last updated v4.7.0) (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
                /// @solidity memory-safe-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: @openzeppelin/contracts/token/ERC20/extensions/draft-IERC20Permit.sol


// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol


// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;




/**
 * @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));
        }
    }

    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @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/introspection/IERC165.sol


// 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/IERC721.sol


// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;


/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: 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 Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}

// File: contracts/pioneer.sol


pragma solidity ^0.8.9;









// @@@@@@@@@@@@@@@@@@@@@@@@@@&&&&&&&&&&&&&&&&&&&&&&@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
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// @@@@@@@@@@@@@@@@@@@@@@&&,,,,  &&,,,,,,    &&,,,,,,,,**&&@@@@@@@@@@@@@@@@@@@@@@@@
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// @@@@@@@@@@@@@@&&**&&,,,,&&,,,,,,&&&&&&,,,,,,,,&&,,&&,,,,,,,,,,&&@@@@@@@@@@@@@@@@
// @@@@@@@@@@@@@@@@&&&&,,,,,,&&&&&&      &&&&&&&&,,,,,,&&,,,,,,&&@@@@@@@@@@@@@@@@@@
// @@@@@@@@@@@@@@@@@@&&,,&&                      &&,,,,******&&@@@@@@@@@@@@@@@@@@@@
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// @@@@@@@@@@@@@@@@@@&&,,&&    ,,,,        ,,,,    &&,,******&&@@@@@@@@@@@@@@@@@@@@
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// @@@@@@@@@@@@@@@@@@&&  &&,,,,,,,,,,,,,,,,,,,,&&      ....&&@@@@@@@@@@@@@@@@@@@@@@
// @@@@@@@@@@@@@@@@@@@@&&&&,,,,,,,,,,**,,,,,,,,,,&&......&&@@@@@@@@@@@@@@@@@@@@@@@@
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// @@@@@@@@@@@@  ░░███░░░░███   ███░░░░░███ ░░███░░░░░███░░███░░░░░█   @@@@@@@@@@@@
// @@@@@@@@@@@@   ░███   ░░███ ███     ░░███ ░███    ░███ ░███  █ ░    @@@@@@@@@@@@
// @@@@@@@@@@@@   ░███    ░███░███      ░███ ░██████████  ░██████      @@@@@@@@@@@@
// @@@@@@@@@@@@   ░███    ░███░███      ░███ ░███░░░░░░   ░███░░█      @@@@@@@@@@@@
// @@@@@@@@@@@@   ░███    ███ ░░███     ███  ░███         ░███ ░   █   @@@@@@@@@@@@
// @@@@@@@@@@@@   ██████████   ░░░███████░   █████        ██████████   @@@@@@@@@@@@
// @@@@@@@@@@@@  ░░░░░░░░░░      ░░░░░░░    ░░░░░        ░░░░░░░░░░    @@@@@@@@@@@@
// @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

contract Pioneer is ERC721Holder, Ownable, Pausable, ReentrancyGuard {
    using SafeERC20 for IERC20;

    IERC20 public dopes;
    IERC721 public dopers;

    uint256 public totalClaimedDopes;
    uint8 public winner; // if winner is 0 then not endgame
    uint256 public endGameReward;

    enum Species {
        Human,
        King,
        Angel,
        Devil,
        Zombie
    }

    enum VoteSide {
        None,
        Angel,
        Devil
    }

    uint8 public constant MAX_SPECIES = 5;
    uint8 public constant MAX_LAYER = 3;
    uint8 public constant MAX_CASTLE_SIZE = 61;
    uint8 public constant MAX_LEVEL = 5;
    uint8 public constant WINNER_BENEFIT_RATIO = 30; //천사 악마 이길때 claim 비율(30% 추가 Claim)
    uint8 public constant DOUBLE_WINNER_BENEFIT_RATIO = 50; //천사 악마 2배 이상 이길때 claim 비율(50% 추가 Claim)
    uint8 public constant FARM_BENEFIT_RATIO = 10;
    uint8 public constant ANGEL_WINNING_BENEFIT_RATIO = 2;
    uint8 public constant MAX_ZOMBIES = 5; // 성당 최대 좀비 수
    uint16 public constant BLOCKS_PER_DAY = 7200; // 좀비 최대 있을 시간(최대 3일)
    uint16 public constant BLOCKS_PER_WEEK = 50400;
    uint256 public constant CASTLE_PRICE = 2 * 10**5 * 10**18;
    uint256 public constant FLOATING_FACTOR = 10**9;

    //Game balance parameters
    uint8 public DELTA = 30; // 토크노믹스를 위한 조정 변수
    uint16 public BARRICADE_PRICE = 5000;
    uint16 public ZOMBIE_TIME = 3000;
    uint32 public BLOCKS_PER_3DAYS = 21600; // 좀비 최대 있을 시간(최대 3일)
    uint32 public ZOMBIE_DELTA = 200000;
    uint256 public TEMPLE_PRICE = 1 * 10**6 * 10**18;

    struct Castle {
        bool hasFarm;
        uint8 barricades;
        uint8 level;
        uint8 zombies;
        uint16 workers;
        uint256 angelInfluences;
        uint256 devilInfluences;
        uint256 ownerTokenID; // 성 주인
        uint256 taxPool; // castle에 쌓인 세금량
        uint256 balance; // 현재 dope 보유량
        uint256 lastAttackedBlock;
    }

    struct Character {
        uint8 voteSide; // 0 : none, 1 : angel side, 2 : devil side
        uint8 castleId; // 0 : null castle, 1 ~ : castle number | 캐릭터가 현재 있는 캐슬
        uint8 species; // default 0 -> human, 1 -> king, 2 -> angel, 3 -> devil, 4 -> zombie
        uint8 level; // 강화도
        bool claimable;
        bool isCastleOwner;
        uint256 lastActionedBlock;
    }

    struct CastleLevel {
        uint8 taxRatio; // 10, 9, 8, 7, 5
        uint256 upgradeBalance;
        uint256 levelUpPrice; // 27 * 10**3 * 10**DECIMAL, 32 * 10**3 * 10**DECIMAL, 35 * 10**3 * 10**DECIMAL, 4 * 10**4 * 10**DECIMAL, 0
    }

    struct Zombie {
        uint256 lastAttackedBlock; // 마지막으로 성을 공격한시간
    }

    // 레이어마다 성이 있고, 처음에 공개되는 레이언은 0번 레이어. 다음 레이어가 공개되려면 여기에 정의된 수 이상의 성이 activate상태여야한다.
    uint256[MAX_LAYER] public layerCondition = [
        0,
        20 * 10**6 * 10**18,
        36 * 10**7 * 10**18
    ];
    uint8[MAX_LAYER] public castleIdxByLayer = [4, 32, 60];
    uint8[MAX_SPECIES] public dopenesses = [20, 30, 40, 40, 40];
    uint8[MAX_LEVEL] public dopenessesByUpgrade = [6, 15, 27, 42, 60];

    // castle level에 따른 세금률
    CastleLevel[MAX_LEVEL + 1] public castleInfoByLevel; // default is 1

    uint256 public totalAngelInfluences; // 전체 Angel의 voting power
    uint256 public totalDevilInfluences; // 전체 Devil의 voting power

    mapping(uint256 => Character) public characters; // tokenId to Character
    mapping(uint8 => Castle) public castles;
    address public templeSink; //addreess to receive DOPES from temple purchases

    constructor(
        address dopersAddress,
        address dopesAddress,
        address _templeSink
    ) {
        dopers = IERC721(dopersAddress);
        dopes = IERC20(dopesAddress);
        templeSink = _templeSink;

        castleInfoByLevel[0] = CastleLevel({
            taxRatio: 10,
            upgradeBalance: 4 * 10**6 * 10**18,
            levelUpPrice: 0
        });
        castleInfoByLevel[1] = CastleLevel({
            taxRatio: 10,
            upgradeBalance: 4 * 10**6 * 10**18,
            levelUpPrice: 0
        });
        castleInfoByLevel[2] = CastleLevel({
            taxRatio: 9,
            upgradeBalance: 12 * 10**5 * 10**18,
            levelUpPrice: 27 * 10**3 * 10**18
        });
        castleInfoByLevel[3] = CastleLevel({
            taxRatio: 8,
            upgradeBalance: 16 * 10**5 * 10**18,
            levelUpPrice: 32 * 10**3 * 10**18
        });
        castleInfoByLevel[4] = CastleLevel({
            taxRatio: 7,
            upgradeBalance: 2 * 10**6 * 10**18,
            levelUpPrice: 35 * 10**3 * 10**18
        });
        castleInfoByLevel[5] = CastleLevel({
            taxRatio: 5,
            upgradeBalance: 32 * 10**5 * 10**18,
            levelUpPrice: 4 * 10**4 * 10**18
        });

        uint256 initialBalance = castleInfoByLevel[0].upgradeBalance * 3;
        castles[1] = Castle({
            hasFarm: false,
            barricades: 0,
            level: 5,
            zombies: 0,
            workers: 0,
            angelInfluences: 0,
            devilInfluences: 0,
            ownerTokenID: 0,
            taxPool: 0,
            balance: initialBalance,
            lastAttackedBlock: 0
        });
        castles[2] = Castle({
            hasFarm: false,
            barricades: 0,
            level: 5,
            zombies: 0,
            workers: 0,
            angelInfluences: 0,
            devilInfluences: 0,
            ownerTokenID: 0,
            taxPool: 0,
            balance: initialBalance,
            lastAttackedBlock: 0
        });
        castles[3] = Castle({
            hasFarm: false,
            barricades: 0,
            level: 5,
            zombies: 0,
            workers: 0,
            angelInfluences: 0,
            devilInfluences: 0,
            ownerTokenID: 0,
            taxPool: 0,
            balance: initialBalance,
            lastAttackedBlock: 0
        });
        castles[4] = Castle({
            hasFarm: false,
            barricades: 0,
            level: 5,
            zombies: 0,
            workers: 0,
            angelInfluences: 0,
            devilInfluences: 0,
            ownerTokenID: 0,
            taxPool: 0,
            balance: initialBalance,
            lastAttackedBlock: 0
        });

        _pause();
    }

    /* ========== VIEWS ========== */

    function ownerOfCastle(uint8 castleId)
        public
        view
        verifyCastle(castleId, true)
        returns (address)
    {
        return dopers.ownerOf(castles[castleId].ownerTokenID);
    }

    function calculationRewards(uint256 tokenId)
        public
        view
        returns (
            uint256 reward,
            uint256 tax,
            bool isBuzzerBeater
        )
    {
        uint8 castleId = characters[tokenId].castleId;
        uint256 balance = castles[castleId].balance;

        if (castleId == 0 || balance == 0) return (0, 0, false);

        isBuzzerBeater = false;
        uint8 species = characters[tokenId].species;
        uint8 taxRate = 0;

        reward = _min(
            block.number - characters[tokenId].lastActionedBlock,
            (
                species == uint8(Species.Zombie)
                    ? BLOCKS_PER_3DAYS
                    : BLOCKS_PER_WEEK
            )
        );

        // balance factor
        if (balance <= 10**6 * 10**18) {
            reward *= 7;
        } else if (balance <= 2 * 10**6 * 10**18) {
            reward *= 8;
        } else if (balance <= 3 * 10**6 * 10**18) {
            reward *= 9;
        } else if (balance <= 4 * 10**6 * 10**18) {
            reward *= 10;
        } else {
            reward *= 11;
        }

        reward *=
            dopenesses[characters[tokenId].species] +
            (
                characters[tokenId].level > 0
                    ? dopenessesByUpgrade[characters[tokenId].level - 1]
                    : 0
            );

        if (species == uint8(Species.Zombie)) {
            reward *= castles[castleId].workers;
            reward *= ZOMBIE_DELTA;
        } else {
            // production speed
            uint8 productionSpeedRatio = 100;
            if (castles[castleId].hasFarm) {
                productionSpeedRatio += FARM_BENEFIT_RATIO;
            }
            if (totalAngelInfluences > totalDevilInfluences) {
                // 밸런싱~~ Peace!
                productionSpeedRatio += totalAngelInfluences >=
                    totalDevilInfluences * 2
                    ? 0
                    : ANGEL_WINNING_BENEFIT_RATIO;
            } else if (totalAngelInfluences < totalDevilInfluences) {
                productionSpeedRatio -= ANGEL_WINNING_BENEFIT_RATIO;
            }

            reward *= productionSpeedRatio;

            uint8 winningRatio = 100;
            if (species == uint8(Species.Angel)) {
                if (
                    castles[castleId].angelInfluences >
                    castles[castleId].devilInfluences
                ) {
                    winningRatio += castles[castleId].angelInfluences >=
                        castles[castleId].devilInfluences * 2
                        ? 30
                        : 10;
                }
            } else if (species == uint8(Species.Devil)) {
                if (
                    castles[castleId].devilInfluences >
                    castles[castleId].angelInfluences
                ) {
                    winningRatio += castles[castleId].devilInfluences >=
                        castles[castleId].angelInfluences * 2
                        ? 30
                        : 10;
                }
            }

            reward *= winningRatio;
            // Zombie effect
            uint8 zombieDecayRate = 10;
            if (
                (block.number - castles[castleId].lastAttackedBlock) <
                BLOCKS_PER_3DAYS
            ) {
                zombieDecayRate -= castles[castleId].zombies;
            }

            reward *= zombieDecayRate;
            reward *= DELTA;

            if (species != uint8(Species.King)) {
                if (castles[castleId].level != 0) {
                    taxRate = castleInfoByLevel[castles[castleId].level]
                        .taxRatio;
                }
            }
        }

        reward *= FLOATING_FACTOR;
        if (balance <= reward) {
            reward = castles[castleId].balance;
            tax = (reward * taxRate) / 10**2;
            if (castles[castleId].level != 0) {
                reward += 20000 * 10**18 * castles[castleId].level;
                isBuzzerBeater = true;
            }
        } else {
            tax = (reward * taxRate) / 10**2;
        }

        reward -= tax;

        return (reward, tax, isBuzzerBeater);
    }

    /* ========== INTERNALS ========== */

    function _min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    function _influence(
        uint8 voteSide,
        uint8 castleId,
        uint8 dopeness,
        bool isPositive
    ) internal {
        if (voteSide == uint8(VoteSide.Angel)) {
            if (isPositive) {
                castles[castleId].angelInfluences += dopeness;
                totalAngelInfluences += dopeness;
            } else {
                castles[castleId].angelInfluences -= dopeness;
                totalAngelInfluences -= dopeness;
            }
        } else {
            if (isPositive) {
                castles[castleId].devilInfluences += dopeness;
                totalDevilInfluences += dopeness;
            } else {
                castles[castleId].devilInfluences -= dopeness;
                totalDevilInfluences -= dopeness;
            }
        }
    }

    function _sendReward(
        uint256 tokenId,
        uint8 castleId,
        uint256 reward,
        uint256 tax,
        bool isBuzzerBeater
    ) internal {
        // accumulate tax
        castles[castleId].taxPool += tax;

        // send reward
        dopes.safeTransfer(_msgSender(), reward);
        totalClaimedDopes += reward;

        if (isBuzzerBeater) {
            emit BuzzerBeater(
                _msgSender(),
                tokenId,
                castleId,
                castles[castleId].level
            );
            castles[castleId].balance = 0;
        } else {
            castles[castleId].balance -= (reward + tax);
        }
    }

    function _isCastleActivated(uint8 castleId) internal view returns (bool) {
        if (castleId > 0 && castleId <= castleIdxByLayer[0]) return true;
        if (
            (castleId > castleIdxByLayer[0] &&
                castleId <= castleIdxByLayer[1]) &&
            totalClaimedDopes >= layerCondition[1]
        ) {
            return true;
        }
        if (
            (castleId > castleIdxByLayer[1] &&
                castleId <= castleIdxByLayer[2]) &&
            totalClaimedDopes >= layerCondition[2]
        ) {
            return true;
        }
        return false;
    }

    function _infect(
        uint256 tokenId,
        uint8 castleId,
        uint8 oldCastleId
    ) internal isAvailableZombie(tokenId, castleId) {
        if (castles[castleId].barricades == 0) {
            // infect case
            require(
                castles[castleId].zombies < MAX_ZOMBIES,
                "reached the maximum zombie limit"
            );
            castles[castleId].zombies++;
            castles[castleId].lastAttackedBlock = block.number;

            if (oldCastleId != 0) {
                castles[oldCastleId].zombies--;
            }

            characters[tokenId].castleId = castleId;
            characters[tokenId].lastActionedBlock = block.number;
        } else {
            // demolish barricades case
            if (oldCastleId != 0) {
                castles[oldCastleId].zombies--;
                characters[tokenId].castleId = 0;
            }
            castles[castleId].barricades--;
            characters[tokenId].lastActionedBlock = block.number;

            uint256 demolishReward = BARRICADE_PRICE * 10**18;
            emit AttackBarricade(
                _msgSender(),
                tokenId,
                castleId,
                demolishReward
            );

            dopes.safeTransfer(_msgSender(), demolishReward);
        }
    }

    /* ========== EXTERNALS ========== */

    function work(
        uint256[] memory tokenIds,
        uint256[] calldata oldCastleIds,
        uint8 castleId,
        uint8 voteSide
    ) external nonReentrant whenNotPaused verifyCastle(castleId, true) {
        // 1. idle 상태에서 work
        // 2. work 상태에서 다른 성으로 work
        // 3. zombie의 경우 바이케이드가 있으면 demolish
        require(tokenIds.length != 0, "no tokenIds provided");

        uint256 totalReward = 0;
        uint256 totalTax = 0;

        for (uint256 i = 0; i < tokenIds.length; i++) {
            uint256 tokenId = tokenIds[i];
            uint8 oldCastleId = characters[tokenId].castleId;

            require(oldCastleId != castleId, "already exists in this castle");
            require(
                _msgSender() == dopers.ownerOf(tokenId),
                "msg sender is not doper's owner"
            );

            (uint256 reward, uint256 tax, bool isBuzzerBeater) = this
                .calculationRewards(tokenId);

            uint8 species = characters[tokenId].species;
            if (species == uint8(Species.Zombie)) {
                _infect(tokenId, castleId, oldCastleId);
            } else {
                if (
                    species == uint8(Species.Human) ||
                    species == uint8(Species.King)
                ) {
                    require(
                        voteSide != uint8(VoteSide.None),
                        "human or king dopers must vote"
                    );
                    require(voteSide <= uint8(VoteSide.Devil), "invalid vote");
                    uint8 dopeness = dopenesses[species];

                    if (oldCastleId == 0) {
                        characters[tokenId].voteSide = voteSide;
                        _influence(voteSide, castleId, dopeness, true);
                    } else {
                        _influence(
                            characters[tokenId].voteSide,
                            oldCastleId,
                            dopeness,
                            false
                        );

                        characters[tokenId].voteSide = voteSide;

                        _influence(voteSide, castleId, dopeness, true);
                    }
                }

                castles[castleId].workers++;

                if (oldCastleId != 0) {
                    castles[oldCastleId].workers--;
                }

                characters[tokenId].castleId = castleId;
                characters[tokenId].lastActionedBlock = block.number;
            }

            if (reward > 0) {
                _sendReward(tokenId, oldCastleId, reward, tax, isBuzzerBeater);

                totalTax += tax;
                totalReward += reward;
            }
        }
        emit Claim(_msgSender(), tokenIds, totalReward, totalTax);
        emit Worked(_msgSender(), tokenIds, oldCastleIds, castleId);
    }

    function claimDope(uint256[] memory tokenIds) external nonReentrant {
        require(tokenIds.length != 0, "no tokenIds provided");

        uint256 totalReward = 0;
        uint256 totalTax = 0;
        for (uint256 i = 0; i < tokenIds.length; i++) {
            require(
                _msgSender() == dopers.ownerOf(tokenIds[i]),
                "msg sender is not doper's owner"
            );
            require(
                characters[tokenIds[i]].species != uint8(Species.Zombie),
                "zombies can not directly claim"
            );

            (uint256 reward, uint256 tax, bool isBuzzerBeater) = this
                .calculationRewards(tokenIds[i]);

            if (reward > 0) {
                _sendReward(
                    tokenIds[i],
                    characters[tokenIds[i]].castleId,
                    reward,
                    tax,
                    isBuzzerBeater
                );

                totalTax += tax;
                totalReward += reward;

                characters[tokenIds[i]].lastActionedBlock = block.number;
            }

            if (isBuzzerBeater) break;
        }
        emit Claim(_msgSender(), tokenIds, totalReward, totalTax);
    }
 
    function upgradeDoper(uint256 tokenId, uint8 level)
        external
        nonReentrant
        whenNotPaused
        onlyDoperOwner(tokenId)
    {
        require(level <= MAX_LEVEL, "invalid level");
        uint8 castleId = characters[tokenId].castleId;
        require(castleId > castleIdxByLayer[0], "invalid castle");
        require(
            characters[tokenId].level < level,
            "level has already been reached"
        );
        require(castles[castleId].level >= level, "insufficient castle level");
        uint256 price = (dopenessesByUpgrade[level - 1] -
            (
                characters[tokenId].level == 0
                    ? 0
                    : dopenessesByUpgrade[characters[tokenId].level - 1]
            )) * 1000;

        if (totalDevilInfluences > totalAngelInfluences) {
            price *= totalDevilInfluences > totalAngelInfluences * 2 ? 10 : 8;
        } else if (totalDevilInfluences < totalAngelInfluences) {
            price *= 12;
        } else {
            // it handles totalDevilInfluences == totalAngelInfluences
            price *= 10;
        }

        price *= 10**17;
        dopes.safeTransferFrom(_msgSender(), address(this), price);
        characters[tokenId].level = level;

        emit UpgradeDoper(_msgSender(), tokenId, level);
    }

    function multiUpgradeDoper(uint256[] memory tokenId, uint8[] memory level)
        public
        nonReentrant
        whenNotPaused
    {
        for (uint256 i = 0; i < tokenId.length; i++) {
            require(level[i] <= MAX_LEVEL, "invalid level");
            uint8 castleId = characters[tokenId[i]].castleId;
            require(castleId > castleIdxByLayer[0], "invalid castle");
            require(
                characters[tokenId[i]].level < level[i],
                "level has already been reached"
            );
            require(
                castles[castleId].level >= level[i],
                "insufficient castle level"
            );
            uint256 price = (dopenessesByUpgrade[level[i] - 1] -
                (
                    characters[tokenId[i]].level == 0
                        ? 0
                        : dopenessesByUpgrade[characters[tokenId[i]].level - 1]
                )) * 1000;

            if (totalDevilInfluences > totalAngelInfluences) {
                price *= totalDevilInfluences > totalAngelInfluences * 2
                    ? 10
                    : 8;
            } else if (totalDevilInfluences < totalAngelInfluences) {
                price *= 12;
            } else {
                // it handles totalDevilInfluences == totalAngelInfluences
                price *= 10;
            }

            price *= 10**17;
            dopes.safeTransferFrom(_msgSender(), address(this), price);
            characters[tokenId[i]].level = level[i];

            emit UpgradeDoper(_msgSender(), tokenId[i], level[i]);
        }
    }

    /*************
     * For King *
     *************/

    function purchaseCastle(uint256 tokenId, uint8 castleId)
        external
        nonReentrant
        whenNotPaused
        onlyDoperOwner(tokenId)
        verifyCastle(castleId, false)
    {
        require(
            castleId > castleIdxByLayer[0],
            "init castle cannot be purchased"
        );
        require(
            characters[tokenId].species == uint8(Species.King),
            "doper must be king"
        );
        require(_isCastleActivated(castleId), "castle is not activated");
        require(
            characters[tokenId].isCastleOwner == false,
            "A king already has a castle."
        );

        dopes.safeTransferFrom(_msgSender(), address(this), CASTLE_PRICE);

        castles[castleId] = Castle({
            hasFarm: false,
            barricades: 0,
            level: 1,
            zombies: 0,
            workers: 0,
            angelInfluences: 0,
            devilInfluences: 0,
            ownerTokenID: tokenId,
            taxPool: 0,
            balance: castleInfoByLevel[0].upgradeBalance,
            lastAttackedBlock: 0
        });

        characters[tokenId].isCastleOwner = true;

        emit PurchaseCastle(_msgSender(), castleId);
    }

    function purchaseTemple(uint256 tokenId)
        external
        nonReentrant
        onlyDoperOwner(tokenId)
    {
        require(
            block.number >= BLOCKS_PER_DAY + castles[0].lastAttackedBlock,
            "too soon to buy the temple again"
        );
        require(
            characters[tokenId].species == uint8(Species.King),
            "doper must be king"
        );
        require(castles[0].ownerTokenID != tokenId, "You already own the temple");
        dopes.safeTransferFrom(_msgSender(), templeSink, TEMPLE_PRICE);

        castles[0].ownerTokenID = tokenId;
        castles[0].lastAttackedBlock = block.number;

        emit PurchaseCastle(_msgSender(), 0);
    }

    function upgradeCastle(uint8 castleId)
        external
        nonReentrant
        whenNotPaused
        onlyCastleOwner(castleId)
        verifyCastle(castleId, true)
    {
        require(castles[castleId].balance == 0, "castle balance remains");
        require(
            castles[castleId].level < MAX_LEVEL,
            "castle already reached max level"
        );
        uint256 price = castleInfoByLevel[castles[castleId].level + 1]
            .levelUpPrice;
        dopes.safeTransferFrom(_msgSender(), address(this), price);
        castles[castleId].level++;
        castles[castleId].balance = castleInfoByLevel[castles[castleId].level]
            .upgradeBalance;
        emit UpgradeCastle(_msgSender(), castleId, castles[castleId].level);
    }

    function claimTax(uint8 castleId)
        external
        nonReentrant
        onlyCastleOwner(castleId)
        verifyCastle(castleId, true)
    {
        require(castles[castleId].taxPool > 0, "taxpool is empty");
        dopes.safeTransfer(_msgSender(), castles[castleId].taxPool);
        totalClaimedDopes += castles[castleId].taxPool;

        emit ClaimTax(_msgSender(), castleId, castles[castleId].taxPool);
        castles[castleId].taxPool = 0;
    }

    function buildFarm(uint8 castleId)
        external
        nonReentrant
        whenNotPaused
        onlyCastleOwner(castleId)
        verifyCastle(castleId, true)
    {
        require(
            castles[castleId].hasFarm == false,
            "farm has already been installed"
        );
        uint256 price = 60000;
        if (castles[castleId].level == 2) {
            price -= 20000;
        } else if (castles[castleId].level == 3) {
            price -= 26000;
        } else if (castles[castleId].level == 4) {
            price -= 34000;
        } else if (castles[castleId].level == 5) {
            price -= 44000;
        }
        price *= 10**18;
        dopes.safeTransferFrom(_msgSender(), address(this), price);
        castles[castleId].hasFarm = true;
        emit PurchaseFarm(_msgSender(), castleId, price);
    }

    function buildBarricade(uint8 castleId, uint8 amount)
        external
        nonReentrant
        whenNotPaused
        onlyCastleOwner(castleId)
        verifyCastle(castleId, true)
    {
        require(
            castles[castleId].barricades + amount <= 5,
            "exceeded installable barricades"
        );

        uint256 price = BARRICADE_PRICE * 10**18 * amount;
        dopes.safeTransferFrom(_msgSender(), address(this), price);
        castles[castleId].barricades += amount;
        emit PurchaseBarricades(_msgSender(), castleId, amount, price);
    }

    /*************
     * For EndGame *
     *************/

    function endGameClaim(uint256 tokenId)
        external
        onlyDoperOwner(tokenId)
        nonReentrant
    {
        require(winner != 0, "The game is not over yet.");
        require(
            characters[tokenId].claimable == false,
            "have already been paid"
        );

        uint8 species = characters[tokenId].species;
        require(
            species == uint8(Species.Angel) || species == uint8(Species.Devil),
            "doper must be immortal"
        );

        if (winner == uint8(Species.Angel)) {
            require(species == uint8(Species.Angel), "winner is angel");
        } else {
            // winner == uint8(Species.Devil) case
            require(species == uint8(Species.Devil), "winner is devil");
        }

        characters[tokenId].claimable = true;
        dopes.safeTransfer(_msgSender(), endGameReward);
        emit EndGameClaim(_msgSender(), tokenId);
    }

    /* ========== RESTRICTED FUNCTIONS ========== */

    function pause() external onlyOwner {
        _pause();
    }

    function unpause() external onlyOwner {
        _unpause();
    }

    function setGameParameters(
        uint8 _delta,
        uint16 _barricadePrice,
        uint16 _zombieTime,
        uint32 _blocksPerThreeDays,
        uint32 _zombieDelta,
        uint256 _templePrice
    ) external onlyOwner whenPaused {
        DELTA = _delta;
        BARRICADE_PRICE = _barricadePrice;
        ZOMBIE_TIME = _zombieTime;
        BLOCKS_PER_3DAYS = _blocksPerThreeDays;
        ZOMBIE_DELTA = _zombieDelta;
        TEMPLE_PRICE = _templePrice;
    }

    function registerDoper(uint256[] memory tokenIds, uint8 species)
        external
        whenPaused
        onlyOwner
    {
        require(tokenIds.length != 0, "no tokenIds provided");
        require(
            species >= uint8(Species.Human) && species <= uint8(Species.Zombie),
            "invalid species"
        );

        for (uint256 i = 0; i < tokenIds.length; i++) {
            require(tokenIds[i] >= 0 && tokenIds[i] < 10000, "invalid tokenId");
            characters[tokenIds[i]].species = species;
        }
    }

    function endgame() external onlyOwner {
        require(winner == 0, "The game is already over");
        require(totalClaimedDopes > 6 * 10**26, "can't end the game hastily");
        require(
            totalAngelInfluences != totalDevilInfluences,
            "There must be a winner"
        );
        endGameReward = dopes.balanceOf(address(this)) / 500;
        winner = totalAngelInfluences > totalDevilInfluences
            ? uint8(Species.Angel)
            : uint8(Species.Devil);
        _pause();
        emit EndGame(totalAngelInfluences, totalDevilInfluences);
    }

    /* ========== MODIFIERS ========== */

    modifier onlyCastleOwner(uint8 castleId) {
        require(
            dopers.ownerOf(castles[castleId].ownerTokenID) == _msgSender(),
            "msg sender is not castle's owner"
        );
        _;
    }

    modifier onlyDoperOwner(uint256 tokenId) {
        require(
            dopers.ownerOf(tokenId) == _msgSender(),
            "msg sender is not token owner"
        );
        _;
    }

    modifier verifyCastle(uint8 castleId, bool saled) {
        require(
            castleId > 0 && castleId < MAX_CASTLE_SIZE,
            "invalid castle index"
        );
        if (saled) {
            if (castleId > 4) {
                require(
                    castles[castleId].ownerTokenID != 0,
                    "castle was not purchased"
                );
            }
        } else {
            require(
                castles[castleId].ownerTokenID == 0,
                "castled already sold"
            );
        }
        _;
    }

    modifier isAvailableZombie(uint256 tokenId, uint8 castleId) {
        require(
            castleId > castleIdxByLayer[0],
            "zombies can't act in 1st layer"
        );

        require(
            (block.number - characters[tokenId].lastActionedBlock) >
                ZOMBIE_TIME,
            "zombie can't act yet"
        );
        _;
    }

    /* ========== EVENTS ========== */
    event Worked(
        address indexed user,
        uint256[] tokenIds,
        uint256[] oldCastleIds,
        uint8 newCastleId
    );
    event Claim(
        address indexed user,
        uint256[] tokenIds,
        uint256 reward,
        uint256 tax
    );
    event BuzzerBeater(
        address indexed user,
        uint256 tokenId,
        uint8 castleId,
        uint8 level
    );
    event UpgradeCastle(address indexed user, uint8 castleId, uint8 level);
    event UpgradeDoper(address indexed user, uint256 tokenId, uint8 level);
    event ClaimTax(address indexed user, uint8 castleId, uint256 tax);
    event PurchaseCastle(address indexed user, uint8 castleId);
    event PurchaseFarm(address indexed user, uint8 castleId, uint256 price);
    event PurchaseBarricades(
        address indexed user,
        uint8 castleId,
        uint8 amount,
        uint256 price
    );
    event AttackBarricade(
        address indexed user,
        uint256 tokenId,
        uint8 castleId,
        uint256 reward
    );
    event EndGame(uint256 endAngelInfluences, uint256 endDevilInfluences);
    event EndGameClaim(address indexed user, uint256 tokenId);
}