// File: /contracts/ERC721/Access/ERC721Firewall.sol



// SPDX-License-Identifier: MIT
pragma solidity =0.8.6;

import "../../Access/Whitelist.sol";
import "../../Access/Allocator.sol";

contract ERC721Firewall is Allocator, Whitelist {
    
    constructor(uint256 baseMaxAllocation_, Phase[] memory phases_) {
        initializeWhitelist();
        setWhitelistActive(false);
        initializeAllocator();
        setAllocatorActive(false);
        setBaseAllocation(baseMaxAllocation_);
        if (phases_.length > 0) setPhases(phases_);
    }
}
// File: /contracts/Access/Whitelist.sol



// SPDX-License-Identifier: MIT
pragma solidity =0.8.6;

import './AccessMaintainer.sol';
import './IWhitelist.sol';

contract Whitelist is AccessMaintainer, IWhitelist {
    // Mapping address to _whitelist index starting from 1, 0 means that address is not whitelisted
    mapping(address => uint256) internal whitelistIdx;
    address[] public whitelist;
    bool public whitelistActive;
    bool public whitelistInitialized;

    function initializeWhitelist() public onlyOwner {
        require(!whitelistInitialized, 'Whitelist: already initialized');
        whitelistInitialized = true;
        setWhitelistActive(true);
    }

    function addToWhitelist(address[] memory wallets) external override onlyMaintainer {
        for (uint i=0; i < wallets.length; i++) addAddress(wallets[i]);
        emit WhitelistChanged();
    }

    function deleteFromWhitelist(address[] memory wallets) external override onlyMaintainer {
        for(uint i=0; i < wallets.length; i++) removeAddress(wallets[i]);
        emit WhitelistChanged();
    }

    function setWhitelistActive(bool active) public override onlyOwner {
        whitelistActive = active;
        emit WhitelistSet(active);
    }

    function isWhitelistActive() public view override returns (bool) {
        return whitelistInitialized && whitelistActive;
    }

    function isWhitelisted(address wallet) public view override returns (bool) {
        return whitelistIdx[wallet] > 0;
    }

    function queryWhitelist(uint256 _cursor, uint256 _limit) external view override returns (address[] memory) {
        uint len = whitelist.length;
        uint min = _cursor >= len ? len : _cursor;
        uint max = min+_limit >= len ? len : min+_limit;

        address[] memory addrList = new address[](max-min);

        uint j = 0;
        for (uint i=min; i<max; i++) {
            j = i-min;
            addrList[j] = whitelist[i];
        }
        return addrList;
    }

    function removeAddress(address wallet) internal {
        if (isWhitelisted(wallet)) {
            uint256 currentIdx = whitelistIdx[wallet] - 1;
            uint256 lastIndex = whitelist.length - 1;
            address walletToMove = whitelist[lastIndex];
            
            if (wallet != walletToMove) {
                whitelistIdx[walletToMove] = currentIdx+1;
                whitelist[currentIdx] = walletToMove;
            }

            delete whitelistIdx[wallet];
            whitelist.pop();
        }
    }

    function addAddress(address wallet) internal {
        if (!isWhitelisted(wallet)) {
            whitelistIdx[wallet] = whitelist.length + 1;
            whitelist.push(wallet);
        }
    }
}
// File: /contracts/Access/IWhitelist.sol



// SPDX-License-Identifier: MIT
pragma solidity =0.8.6;

interface IWhitelist { 

    event WhitelistSet(bool status);
    event WhitelistChanged();
    
    function addToWhitelist(address[] memory wallets) external;

    function deleteFromWhitelist(address[] memory wallets) external;

    function setWhitelistActive(bool active) external;

    function isWhitelisted(address wallet) external view returns (bool);

    function isWhitelistActive() external view returns (bool);

    function queryWhitelist(uint256 _cursor, uint256 _limit) external view returns (address[] memory);
}
// File: /contracts/Access/IAllocator.sol



// SPDX-License-Identifier: MIT
pragma solidity =0.8.6;

import "@openzeppelin/contracts/utils/Timers.sol";

interface IAllocator {

    struct Allocation {
        address allocator;
        uint256 amount;
    }

    struct Phase {
        Timers.BlockNumber block;
        uint256 mintLimit;
    }

    event MaxBaseAllocation(uint256 amount);
    event MaxAllocation(address indexed allocator, uint256 amount);
    event CurrentAllocation(address indexed allocator, uint256 amount);
    event PhaseSet(uint256 indexed id, uint64 deadline, uint256 limit);
    event AllocatorSet(bool status);

    function setAllocatorActive(bool active) external;

    function isAllocatorActive() external view returns (bool);

    function currentAllocation(address allocator) external view returns(uint256);

    function maximumAllocation(address allocator) external view returns(uint256);

    function totalAllocationLimit() external view returns(uint256);

    function setAllocations(Allocation[] memory allocances) external;

    function setBaseAllocation(uint256 amount) external;

    function setAllocation(address allocator, uint256 amount) external;

    function canAllocate(address allocator, uint256 amount) external view returns(bool, string memory);

    function setPhases(Phase[] memory phases) external;

    function insertPhase(Phase memory phase) external;

    function updatePhase(uint256 phaseId, uint64 timestamp, uint256 minLimit) external;

    function getPhases() external view returns(Phase[] memory);

    function getCurrentPhaseLimit() external view returns(uint256);

    function allocate(address allocator, uint256 amount) external;
}
// File: /contracts/Access/Allocator.sol



// SPDX-License-Identifier: MIT
pragma solidity =0.8.6;

import "@openzeppelin/contracts/utils/Timers.sol";
import './AccessMaintainer.sol';
import './IAllocator.sol';

contract Allocator is AccessMaintainer, IAllocator {
    using Timers for Timers.BlockNumber;

    bool public allocatorActive;
    bool public allocatorInitialized;

    //Phases
    Phase[] internal _phases;

    // Allocation
    uint256 public baseMaxAllocation;
    uint256 internal _totalAllocation;
    mapping(address => uint256) internal _curAllocations;
    mapping(address => uint256) internal _maxAllocations;

    // Modifiers
    modifier onlyWhenAllocatable(address allocator, uint256 amount) {
        (bool allowed, string memory message) = canAllocate(allocator, amount);
        require(allowed, message);
        _;
    }

    function initializeAllocator() public onlyOwner {
        require(!allocatorInitialized, 'Allocator: already initialized');
        allocatorInitialized = true;
        setAllocatorActive(true);
    }

    function setAllocatorActive(bool active) public override onlyOwner {
        allocatorActive = active;
        emit AllocatorSet(active);
    }

    function isAllocatorActive() public view override returns (bool) {
        return allocatorInitialized && allocatorActive;
    }

    function currentAllocation(address allocator) public override view returns(uint256) {
        return _curAllocations[allocator];
    }

    function maximumAllocation(address allocator) public override view returns(uint256) {
        return _maxAllocations[allocator];
    }

    function totalAllocationLimit() public view override returns(uint256) {
        return _totalAllocation;
    }

    function setAllocations(Allocation[] memory allocs) external override onlyMaintainer {
        for (uint i=0; i < allocs.length; i++) {
            setAllocation(allocs[i].allocator, allocs[i].amount);
        }
    }

    function setAllocation(address allocator, uint256 amount) public override onlyMaintainer {
        _maxAllocations[allocator] = amount;
        emit MaxAllocation(allocator, amount);
    }

    function setBaseAllocation(uint256 amount) public override onlyOwner {
        baseMaxAllocation = amount;
        emit MaxBaseAllocation(amount);
    }

    function canAllocate(address allocator, uint256 amount) public view override returns (bool, string memory) {
        uint256 phaseMintLimit = getCurrentPhaseLimit();

        if (!isAllocatorActive()) {
            return (false, "Allocator: cannot allocate yet!");
        }
        if (phaseMintLimit != 0 && (_totalAllocation + amount > phaseMintLimit)) {
            return (false, "Allocator: phase limit reached!");
        }

        uint256 curAllocation = _curAllocations[allocator];
        uint256 maxAllocation = _maxAllocations[allocator];

        if ((maxAllocation != 0 && curAllocation + amount > maxAllocation)
            || (maxAllocation == 0 && curAllocation + amount > baseMaxAllocation))
        {
            return (false, "Allocator: max user allocation limit reached!");
        }

        return (true, "");
    }

    function allocate(address allocator, uint256 amount) public override onlyMaintainer onlyWhenAllocatable(allocator, amount) {
        _curAllocations[allocator] += amount;
        _totalAllocation += amount;
        emit CurrentAllocation(allocator, _curAllocations[allocator]);
    }


    // Phases
    function setPhases(Phase[] memory phases) public override onlyOwner {
        delete _phases;

        for (uint i=0; i < phases.length; i++) {
            insertPhase(phases[i]);
        }
    }

    function insertPhase(Phase memory phase) public override onlyOwner {
        if (_phases.length > 0) {
            Phase storage lastPhase = _phases[_phases.length-1];
            require(lastPhase.block.getDeadline() < phase.block.getDeadline() && lastPhase.mintLimit < phase.mintLimit,
                "Allocator: wrong phase parameters!");
        }

        _phases.push(phase);
        emit PhaseSet({ id: _phases.length-1, deadline: phase.block.getDeadline(), limit: phase.mintLimit });
    }

    function updatePhase(uint256 phaseId, uint64 blockNumber, uint256 minLimit) public override onlyOwner {
        require(phaseId < _phases.length, "Phase do not exist!");

        if (phaseId > 0) {
            Phase storage phaseBefore = _phases[phaseId-1];
            require(phaseBefore.block.getDeadline() < blockNumber && phaseBefore.mintLimit < minLimit,
                "Allocator: wrong phase parameters!");
        }

        if (phaseId < _phases.length-1) {
            Phase storage phaseAfter = _phases[phaseId+1];
            require(phaseAfter.block.getDeadline() > blockNumber && phaseAfter.mintLimit > minLimit,
                "Allocator: wrong phase parameters!");
        }

        Phase storage phaseUp = _phases[phaseId];
        phaseUp.block.setDeadline(blockNumber);
        phaseUp.mintLimit = minLimit;

        emit PhaseSet({id: phaseId, deadline: blockNumber, limit: minLimit});
    }

    function getPhases() external view override returns(Phase[] memory) {
        return _phases;
    }

    function getCurrentPhaseLimit() public view override returns(uint256) {
        for (uint i=0; i < _phases.length; i++) {
            Phase storage nextPhase = _phases[i];
            
            if (!nextPhase.block.isExpired()) {
                return nextPhase.mintLimit;
            }
        }
        return 0;
    }
}
// File: /contracts/Access/AccessMaintainer.sol



// SPDX-License-Identifier: MIT
pragma solidity =0.8.6;

import "@openzeppelin/contracts/access/Ownable.sol";
import '@openzeppelin/contracts/access/AccessControl.sol';
import '@openzeppelin/contracts/utils/Address.sol';

contract AccessMaintainer is Ownable, AccessControl {
    using Address for address;

    bytes32 public constant ADMIN_ROLE = keccak256('ADMIN_ROLE');
    bytes32 public constant MAINTAINER_ROLE = keccak256('MAINTAINER_ROLE');

    modifier onlyMaintainer {
        require(msg.sender == owner() || hasRole(MAINTAINER_ROLE, msg.sender),
            'AccessMaintainer: only owner and or maintainers can call this method');
        _;
    }

    constructor() {
        _setRoleAdmin(ADMIN_ROLE, ADMIN_ROLE);
        _setRoleAdmin(MAINTAINER_ROLE, ADMIN_ROLE);

        _setupRole(ADMIN_ROLE, address(this));
        _setupRole(MAINTAINER_ROLE, owner());
    }

    function addMaintainer(address account) external onlyOwner returns (bool) {
        bytes4 selector = this.grantRole.selector;
        address(this).functionCall(abi.encodeWithSelector(selector, MAINTAINER_ROLE, account));
        return true;
    }

    function delMaintainer(address account) external onlyOwner returns (bool) {
        bytes4 selector = this.revokeRole.selector;
        address(this).functionCall(abi.encodeWithSelector(selector, MAINTAINER_ROLE, account));
        return true;
    }

    function isMaintainer(address account) external view returns (bool) {
        return hasRole(MAINTAINER_ROLE, account);
    }
}
// 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/introspection/ERC165.sol



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

pragma solidity ^0.8.0;

import "./IERC165.sol";

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

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



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

pragma solidity ^0.8.0;

/**
 * @dev Tooling for timepoints, timers and delays
 */
library Timers {
    struct Timestamp {
        uint64 _deadline;
    }

    function getDeadline(Timestamp memory timer) internal pure returns (uint64) {
        return timer._deadline;
    }

    function setDeadline(Timestamp storage timer, uint64 timestamp) internal {
        timer._deadline = timestamp;
    }

    function reset(Timestamp storage timer) internal {
        timer._deadline = 0;
    }

    function isUnset(Timestamp memory timer) internal pure returns (bool) {
        return timer._deadline == 0;
    }

    function isStarted(Timestamp memory timer) internal pure returns (bool) {
        return timer._deadline > 0;
    }

    function isPending(Timestamp memory timer) internal view returns (bool) {
        return timer._deadline > block.timestamp;
    }

    function isExpired(Timestamp memory timer) internal view returns (bool) {
        return isStarted(timer) && timer._deadline <= block.timestamp;
    }

    struct BlockNumber {
        uint64 _deadline;
    }

    function getDeadline(BlockNumber memory timer) internal pure returns (uint64) {
        return timer._deadline;
    }

    function setDeadline(BlockNumber storage timer, uint64 timestamp) internal {
        timer._deadline = timestamp;
    }

    function reset(BlockNumber storage timer) internal {
        timer._deadline = 0;
    }

    function isUnset(BlockNumber memory timer) internal pure returns (bool) {
        return timer._deadline == 0;
    }

    function isStarted(BlockNumber memory timer) internal pure returns (bool) {
        return timer._deadline > 0;
    }

    function isPending(BlockNumber memory timer) internal view returns (bool) {
        return timer._deadline > block.number;
    }

    function isExpired(BlockNumber memory timer) internal view returns (bool) {
        return isStarted(timer) && timer._deadline <= block.number;
    }
}

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



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

pragma solidity ^0.8.0;

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

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

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

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

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

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



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

pragma solidity ^0.8.0;

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

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

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



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

pragma solidity ^0.8.1;

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

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

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

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

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

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

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

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

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

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

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

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

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

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

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

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

// File: @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/access/IAccessControl.sol



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

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (access/AccessControl.sol)

pragma solidity ^0.8.0;

import "./IAccessControl.sol";
import "../utils/Context.sol";
import "../utils/Strings.sol";
import "../utils/introspection/ERC165.sol";

/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms. This is a lightweight version that doesn't allow enumerating role
 * members except through off-chain means by accessing the contract event logs. Some
 * applications may benefit from on-chain enumerability, for those cases see
 * {AccessControlEnumerable}.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context, IAccessControl, ERC165 {
    struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
    }

    mapping(bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

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

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

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

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

    /**
     * @dev Revert with a standard message if `account` is missing `role`.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     */
    function _checkRole(bytes32 role, address account) internal view virtual {
        if (!hasRole(role, account)) {
            revert(
                string(
                    abi.encodePacked(
                        "AccessControl: account ",
                        Strings.toHexString(uint160(account), 20),
                        " is missing role ",
                        Strings.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }

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

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

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

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

        _revokeRole(role, account);
    }

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

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

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

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