// File: @limitbreak/creator-token-contracts/contracts/access/OwnableBasic.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.4;

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

abstract contract OwnableBasic is OwnablePermissions, Ownable {
    function _requireCallerIsContractOwner() internal view virtual override {
        _checkOwner();
    }
}

// File: @limitbreak/creator-token-contracts/contracts/access/OwnablePermissions.sol



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

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

abstract contract OwnablePermissions is Context {
    function _requireCallerIsContractOwner() internal view virtual;
}

// File: @limitbreak/creator-token-contracts/contracts/interfaces/ICreatorToken.sol



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

import "../interfaces/ICreatorTokenTransferValidator.sol";

interface ICreatorToken {
    event TransferValidatorUpdated(address oldValidator, address newValidator);

    function getTransferValidator() external view returns (ICreatorTokenTransferValidator);
    function getSecurityPolicy() external view returns (CollectionSecurityPolicy memory);
    function getWhitelistedOperators() external view returns (address[] memory);
    function getPermittedContractReceivers() external view returns (address[] memory);
    function isOperatorWhitelisted(address operator) external view returns (bool);
    function isContractReceiverPermitted(address receiver) external view returns (bool);
    function isTransferAllowed(address caller, address from, address to) external view returns (bool);
}

// File: @limitbreak/creator-token-contracts/contracts/interfaces/ICreatorTokenTransferValidator.sol



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

import "./IEOARegistry.sol";
import "./ITransferSecurityRegistry.sol";
import "./ITransferValidator.sol";

interface ICreatorTokenTransferValidator is ITransferSecurityRegistry, ITransferValidator, IEOARegistry {}
// File: @limitbreak/creator-token-contracts/contracts/interfaces/IEOARegistry.sol



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

import "@openzeppelin/contracts/utils/introspection/IERC165.sol";

interface IEOARegistry is IERC165 {
    function isVerifiedEOA(address account) external view returns (bool);
}
// File: @limitbreak/creator-token-contracts/contracts/interfaces/ITransferSecurityRegistry.sol



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

import "../utils/TransferPolicy.sol";

interface ITransferSecurityRegistry {
    event AddedToAllowlist(AllowlistTypes indexed kind, uint256 indexed id, address indexed account);
    event CreatedAllowlist(AllowlistTypes indexed kind, uint256 indexed id, string indexed name);
    event ReassignedAllowlistOwnership(AllowlistTypes indexed kind, uint256 indexed id, address indexed newOwner);
    event RemovedFromAllowlist(AllowlistTypes indexed kind, uint256 indexed id, address indexed account);
    event SetAllowlist(AllowlistTypes indexed kind, address indexed collection, uint120 indexed id);
    event SetTransferSecurityLevel(address indexed collection, TransferSecurityLevels level);

    function createOperatorWhitelist(string calldata name) external returns (uint120);
    function createPermittedContractReceiverAllowlist(string calldata name) external returns (uint120);
    function reassignOwnershipOfOperatorWhitelist(uint120 id, address newOwner) external;
    function reassignOwnershipOfPermittedContractReceiverAllowlist(uint120 id, address newOwner) external;
    function renounceOwnershipOfOperatorWhitelist(uint120 id) external;
    function renounceOwnershipOfPermittedContractReceiverAllowlist(uint120 id) external;
    function setTransferSecurityLevelOfCollection(address collection, TransferSecurityLevels level) external;
    function setOperatorWhitelistOfCollection(address collection, uint120 id) external;
    function setPermittedContractReceiverAllowlistOfCollection(address collection, uint120 id) external;
    function addOperatorToWhitelist(uint120 id, address operator) external;
    function addPermittedContractReceiverToAllowlist(uint120 id, address receiver) external;
    function removeOperatorFromWhitelist(uint120 id, address operator) external;
    function removePermittedContractReceiverFromAllowlist(uint120 id, address receiver) external;
    function getCollectionSecurityPolicy(address collection) external view returns (CollectionSecurityPolicy memory);
    function getWhitelistedOperators(uint120 id) external view returns (address[] memory);
    function getPermittedContractReceivers(uint120 id) external view returns (address[] memory);
    function isOperatorWhitelisted(uint120 id, address operator) external view returns (bool);
    function isContractReceiverPermitted(uint120 id, address receiver) external view returns (bool);
}
// File: @limitbreak/creator-token-contracts/contracts/interfaces/ITransferValidator.sol



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

import "../utils/TransferPolicy.sol";

interface ITransferValidator {
    function applyCollectionTransferPolicy(address caller, address from, address to) external view;
}
// File: @limitbreak/creator-token-contracts/contracts/utils/CreatorTokenBase.sol



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

import "../access/OwnablePermissions.sol";
import "../interfaces/ICreatorToken.sol";
import "../interfaces/ICreatorTokenTransferValidator.sol";
import "../utils/TransferValidation.sol";
import "@openzeppelin/contracts/interfaces/IERC165.sol";

/**
 * @title CreatorTokenBase
 * @author Limit Break, Inc.
 * @notice CreatorTokenBase is an abstract contract that provides basic functionality for managing token 
 * transfer policies through an implementation of ICreatorTokenTransferValidator. This contract is intended to be used
 * as a base for creator-specific token contracts, enabling customizable transfer restrictions and security policies.
 *
 * <h4>Features:</h4>
 * <ul>Ownable: This contract can have an owner who can set and update the transfer validator.</ul>
 * <ul>TransferValidation: Implements the basic token transfer validation interface.</ul>
 * <ul>ICreatorToken: Implements the interface for creator tokens, providing view functions for token security policies.</ul>
 *
 * <h4>Benefits:</h4>
 * <ul>Provides a flexible and modular way to implement custom token transfer restrictions and security policies.</ul>
 * <ul>Allows creators to enforce policies such as whitelisted operators and permitted contract receivers.</ul>
 * <ul>Can be easily integrated into other token contracts as a base contract.</ul>
 *
 * <h4>Intended Usage:</h4>
 * <ul>Use as a base contract for creator token implementations that require advanced transfer restrictions and 
 *   security policies.</ul>
 * <ul>Set and update the ICreatorTokenTransferValidator implementation contract to enforce desired policies for the 
 *   creator token.</ul>
 */
abstract contract CreatorTokenBase is OwnablePermissions, TransferValidation, ICreatorToken {
    
    error CreatorTokenBase__InvalidTransferValidatorContract();
    error CreatorTokenBase__SetTransferValidatorFirst();

    address public constant DEFAULT_TRANSFER_VALIDATOR = address(0x0000721C310194CcfC01E523fc93C9cCcFa2A0Ac);
    TransferSecurityLevels public constant DEFAULT_TRANSFER_SECURITY_LEVEL = TransferSecurityLevels.One;
    uint120 public constant DEFAULT_OPERATOR_WHITELIST_ID = uint120(1);

    ICreatorTokenTransferValidator private transferValidator;

    /**
     * @notice Allows the contract owner to set the transfer validator to the official validator contract
     *         and set the security policy to the recommended default settings.
     * @dev    May be overridden to change the default behavior of an individual collection.
     */
    function setToDefaultSecurityPolicy() public virtual {
        _requireCallerIsContractOwner();
        setTransferValidator(DEFAULT_TRANSFER_VALIDATOR);
        ICreatorTokenTransferValidator(DEFAULT_TRANSFER_VALIDATOR).setTransferSecurityLevelOfCollection(address(this), DEFAULT_TRANSFER_SECURITY_LEVEL);
        ICreatorTokenTransferValidator(DEFAULT_TRANSFER_VALIDATOR).setOperatorWhitelistOfCollection(address(this), DEFAULT_OPERATOR_WHITELIST_ID);
    }

    /**
     * @notice Allows the contract owner to set the transfer validator to a custom validator contract
     *         and set the security policy to their own custom settings.
     */
    function setToCustomValidatorAndSecurityPolicy(
        address validator, 
        TransferSecurityLevels level, 
        uint120 operatorWhitelistId, 
        uint120 permittedContractReceiversAllowlistId) public {
        _requireCallerIsContractOwner();

        setTransferValidator(validator);

        ICreatorTokenTransferValidator(validator).
            setTransferSecurityLevelOfCollection(address(this), level);

        ICreatorTokenTransferValidator(validator).
            setOperatorWhitelistOfCollection(address(this), operatorWhitelistId);

        ICreatorTokenTransferValidator(validator).
            setPermittedContractReceiverAllowlistOfCollection(address(this), permittedContractReceiversAllowlistId);
    }

    /**
     * @notice Allows the contract owner to set the security policy to their own custom settings.
     * @dev    Reverts if the transfer validator has not been set.
     */
    function setToCustomSecurityPolicy(
        TransferSecurityLevels level, 
        uint120 operatorWhitelistId, 
        uint120 permittedContractReceiversAllowlistId) public {
        _requireCallerIsContractOwner();

        ICreatorTokenTransferValidator validator = getTransferValidator();
        if (address(validator) == address(0)) {
            revert CreatorTokenBase__SetTransferValidatorFirst();
        }

        validator.setTransferSecurityLevelOfCollection(address(this), level);
        validator.setOperatorWhitelistOfCollection(address(this), operatorWhitelistId);
        validator.setPermittedContractReceiverAllowlistOfCollection(address(this), permittedContractReceiversAllowlistId);
    }

    /**
     * @notice Sets the transfer validator for the token contract.
     *
     * @dev    Throws when provided validator contract is not the zero address and doesn't support 
     *         the ICreatorTokenTransferValidator interface. 
     * @dev    Throws when the caller is not the contract owner.
     *
     * @dev    <h4>Postconditions:</h4>
     *         1. The transferValidator address is updated.
     *         2. The `TransferValidatorUpdated` event is emitted.
     *
     * @param transferValidator_ The address of the transfer validator contract.
     */
    function setTransferValidator(address transferValidator_) public {
        _requireCallerIsContractOwner();

        bool isValidTransferValidator = false;

        if(transferValidator_.code.length > 0) {
            try IERC165(transferValidator_).supportsInterface(type(ICreatorTokenTransferValidator).interfaceId) 
                returns (bool supportsInterface) {
                isValidTransferValidator = supportsInterface;
            } catch {}
        }

        if(transferValidator_ != address(0) && !isValidTransferValidator) {
            revert CreatorTokenBase__InvalidTransferValidatorContract();
        }

        emit TransferValidatorUpdated(address(transferValidator), transferValidator_);

        transferValidator = ICreatorTokenTransferValidator(transferValidator_);
    }

    /**
     * @notice Returns the transfer validator contract address for this token contract.
     */
    function getTransferValidator() public view override returns (ICreatorTokenTransferValidator) {
        return transferValidator;
    }

    /**
     * @notice Returns the security policy for this token contract, which includes:
     *         Transfer security level, operator whitelist id, permitted contract receiver allowlist id.
     */
    function getSecurityPolicy() public view override returns (CollectionSecurityPolicy memory) {
        if (address(transferValidator) != address(0)) {
            return transferValidator.getCollectionSecurityPolicy(address(this));
        }

        return CollectionSecurityPolicy({
            transferSecurityLevel: TransferSecurityLevels.Zero,
            operatorWhitelistId: 0,
            permittedContractReceiversId: 0
        });
    }

    /**
     * @notice Returns the list of all whitelisted operators for this token contract.
     * @dev    This can be an expensive call and should only be used in view-only functions.
     */
    function getWhitelistedOperators() public view override returns (address[] memory) {
        if (address(transferValidator) != address(0)) {
            return transferValidator.getWhitelistedOperators(
                transferValidator.getCollectionSecurityPolicy(address(this)).operatorWhitelistId);
        }

        return new address[](0);
    }

    /**
     * @notice Returns the list of permitted contract receivers for this token contract.
     * @dev    This can be an expensive call and should only be used in view-only functions.
     */
    function getPermittedContractReceivers() public view override returns (address[] memory) {
        if (address(transferValidator) != address(0)) {
            return transferValidator.getPermittedContractReceivers(
                transferValidator.getCollectionSecurityPolicy(address(this)).permittedContractReceiversId);
        }

        return new address[](0);
    }

    /**
     * @notice Checks if an operator is whitelisted for this token contract.
     * @param operator The address of the operator to check.
     */
    function isOperatorWhitelisted(address operator) public view override returns (bool) {
        if (address(transferValidator) != address(0)) {
            return transferValidator.isOperatorWhitelisted(
                transferValidator.getCollectionSecurityPolicy(address(this)).operatorWhitelistId, operator);
        }

        return false;
    }

    /**
     * @notice Checks if a contract receiver is permitted for this token contract.
     * @param receiver The address of the receiver to check.
     */
    function isContractReceiverPermitted(address receiver) public view override returns (bool) {
        if (address(transferValidator) != address(0)) {
            return transferValidator.isContractReceiverPermitted(
                transferValidator.getCollectionSecurityPolicy(address(this)).permittedContractReceiversId, receiver);
        }

        return false;
    }

    /**
     * @notice Determines if a transfer is allowed based on the token contract's security policy.  Use this function
     *         to simulate whether or not a transfer made by the specified `caller` from the `from` address to the `to`
     *         address would be allowed by this token's security policy.
     *
     * @notice This function only checks the security policy restrictions and does not check whether token ownership
     *         or approvals are in place. 
     *
     * @param caller The address of the simulated caller.
     * @param from   The address of the sender.
     * @param to     The address of the receiver.
     * @return       True if the transfer is allowed, false otherwise.
     */
    function isTransferAllowed(address caller, address from, address to) public view override returns (bool) {
        if (address(transferValidator) != address(0)) {
            try transferValidator.applyCollectionTransferPolicy(caller, from, to) {
                return true;
            } catch {
                return false;
            }
        }
        return true;
    }

    /**
     * @dev Pre-validates a token transfer, reverting if the transfer is not allowed by this token's security policy.
     *      Inheriting contracts are responsible for overriding the _beforeTokenTransfer function, or its equivalent
     *      and calling _validateBeforeTransfer so that checks can be properly applied during token transfers.
     *
     * @dev Throws when the transfer doesn't comply with the collection's transfer policy, if the transferValidator is
     *      set to a non-zero address.
     *
     * @param caller  The address of the caller.
     * @param from    The address of the sender.
     * @param to      The address of the receiver.
     */
    function _preValidateTransfer(
        address caller, 
        address from, 
        address to, 
        uint256 /*tokenId*/, 
        uint256 /*value*/) internal virtual override {
        if (address(transferValidator) != address(0)) {
            transferValidator.applyCollectionTransferPolicy(caller, from, to);
        }
    }
}

// File: @limitbreak/creator-token-contracts/contracts/utils/TransferPolicy.sol



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

enum AllowlistTypes {
    Operators,
    PermittedContractReceivers
}

enum ReceiverConstraints {
    None,
    NoCode,
    EOA
}

enum CallerConstraints {
    None,
    OperatorWhitelistEnableOTC,
    OperatorWhitelistDisableOTC
}

enum StakerConstraints {
    None,
    CallerIsTxOrigin,
    EOA
}

enum TransferSecurityLevels {
    Zero,
    One,
    Two,
    Three,
    Four,
    Five,
    Six
}

struct TransferSecurityPolicy {
    CallerConstraints callerConstraints;
    ReceiverConstraints receiverConstraints;
}

struct CollectionSecurityPolicy {
    TransferSecurityLevels transferSecurityLevel;
    uint120 operatorWhitelistId;
    uint120 permittedContractReceiversId;
}

// File: @limitbreak/creator-token-contracts/contracts/utils/TransferValidation.sol



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

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

/**
 * @title TransferValidation
 * @author Limit Break, Inc.
 * @notice A mix-in that can be combined with ERC-721 contracts to provide more granular hooks.
 * Openzeppelin's ERC721 contract only provides hooks for before and after transfer.  This allows
 * developers to validate or customize transfers within the context of a mint, a burn, or a transfer.
 */
abstract contract TransferValidation is Context {
    
    error ShouldNotMintToBurnAddress();

    /// @dev Inheriting contracts should call this function in the _beforeTokenTransfer function to get more granular hooks.
    function _validateBeforeTransfer(address from, address to, uint256 tokenId) internal virtual {
        bool fromZeroAddress = from == address(0);
        bool toZeroAddress = to == address(0);

        if(fromZeroAddress && toZeroAddress) {
            revert ShouldNotMintToBurnAddress();
        } else if(fromZeroAddress) {
            _preValidateMint(_msgSender(), to, tokenId, msg.value);
        } else if(toZeroAddress) {
            _preValidateBurn(_msgSender(), from, tokenId, msg.value);
        } else {
            _preValidateTransfer(_msgSender(), from, to, tokenId, msg.value);
        }
    }

    /// @dev Inheriting contracts should call this function in the _afterTokenTransfer function to get more granular hooks.
    function _validateAfterTransfer(address from, address to, uint256 tokenId) internal virtual {
        bool fromZeroAddress = from == address(0);
        bool toZeroAddress = to == address(0);

        if(fromZeroAddress && toZeroAddress) {
            revert ShouldNotMintToBurnAddress();
        } else if(fromZeroAddress) {
            _postValidateMint(_msgSender(), to, tokenId, msg.value);
        } else if(toZeroAddress) {
            _postValidateBurn(_msgSender(), from, tokenId, msg.value);
        } else {
            _postValidateTransfer(_msgSender(), from, to, tokenId, msg.value);
        }
    }

    /// @dev Optional validation hook that fires before a mint
    function _preValidateMint(address caller, address to, uint256 tokenId, uint256 value) internal virtual {}

    /// @dev Optional validation hook that fires after a mint
    function _postValidateMint(address caller, address to, uint256 tokenId, uint256 value) internal virtual {}

    /// @dev Optional validation hook that fires before a burn
    function _preValidateBurn(address caller, address from, uint256 tokenId, uint256 value) internal virtual {}

    /// @dev Optional validation hook that fires after a burn
    function _postValidateBurn(address caller, address from, uint256 tokenId, uint256 value) internal virtual {}

    /// @dev Optional validation hook that fires before a transfer
    function _preValidateTransfer(address caller, address from, address to, uint256 tokenId, uint256 value) internal virtual {}

    /// @dev Optional validation hook that fires after a transfer
    function _postValidateTransfer(address caller, address from, address to, uint256 tokenId, uint256 value) internal virtual {}
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (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 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/interfaces/IERC165.sol



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

pragma solidity ^0.8.0;

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

// File: @openzeppelin/contracts/interfaces/IERC2981.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (interfaces/IERC2981.sol)

pragma solidity ^0.8.0;

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

/**
 * @dev Interface for the NFT Royalty Standard.
 *
 * A standardized way to retrieve royalty payment information for non-fungible tokens (NFTs) to enable universal
 * support for royalty payments across all NFT marketplaces and ecosystem participants.
 *
 * _Available since v4.5._
 */
interface IERC2981 is IERC165 {
    /**
     * @dev Returns how much royalty is owed and to whom, based on a sale price that may be denominated in any unit of
     * exchange. The royalty amount is denominated and should be paid in that same unit of exchange.
     */
    function royaltyInfo(uint256 tokenId, uint256 salePrice)
        external
        view
        returns (address receiver, uint256 royaltyAmount);
}

// File: @openzeppelin/contracts/token/common/ERC2981.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/common/ERC2981.sol)

pragma solidity ^0.8.0;

import "../../interfaces/IERC2981.sol";
import "../../utils/introspection/ERC165.sol";

/**
 * @dev Implementation of the NFT Royalty Standard, a standardized way to retrieve royalty payment information.
 *
 * Royalty information can be specified globally for all token ids via {_setDefaultRoyalty}, and/or individually for
 * specific token ids via {_setTokenRoyalty}. The latter takes precedence over the first.
 *
 * Royalty is specified as a fraction of sale price. {_feeDenominator} is overridable but defaults to 10000, meaning the
 * fee is specified in basis points by default.
 *
 * IMPORTANT: ERC-2981 only specifies a way to signal royalty information and does not enforce its payment. See
 * https://eips.ethereum.org/EIPS/eip-2981#optional-royalty-payments[Rationale] in the EIP. Marketplaces are expected to
 * voluntarily pay royalties together with sales, but note that this standard is not yet widely supported.
 *
 * _Available since v4.5._
 */
abstract contract ERC2981 is IERC2981, ERC165 {
    struct RoyaltyInfo {
        address receiver;
        uint96 royaltyFraction;
    }

    RoyaltyInfo private _defaultRoyaltyInfo;
    mapping(uint256 => RoyaltyInfo) private _tokenRoyaltyInfo;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC165) returns (bool) {
        return interfaceId == type(IERC2981).interfaceId || super.supportsInterface(interfaceId);
    }

    /**
     * @inheritdoc IERC2981
     */
    function royaltyInfo(uint256 _tokenId, uint256 _salePrice) public view virtual override returns (address, uint256) {
        RoyaltyInfo memory royalty = _tokenRoyaltyInfo[_tokenId];

        if (royalty.receiver == address(0)) {
            royalty = _defaultRoyaltyInfo;
        }

        uint256 royaltyAmount = (_salePrice * royalty.royaltyFraction) / _feeDenominator();

        return (royalty.receiver, royaltyAmount);
    }

    /**
     * @dev The denominator with which to interpret the fee set in {_setTokenRoyalty} and {_setDefaultRoyalty} as a
     * fraction of the sale price. Defaults to 10000 so fees are expressed in basis points, but may be customized by an
     * override.
     */
    function _feeDenominator() internal pure virtual returns (uint96) {
        return 10000;
    }

    /**
     * @dev Sets the royalty information that all ids in this contract will default to.
     *
     * Requirements:
     *
     * - `receiver` cannot be the zero address.
     * - `feeNumerator` cannot be greater than the fee denominator.
     */
    function _setDefaultRoyalty(address receiver, uint96 feeNumerator) internal virtual {
        require(feeNumerator <= _feeDenominator(), "ERC2981: royalty fee will exceed salePrice");
        require(receiver != address(0), "ERC2981: invalid receiver");

        _defaultRoyaltyInfo = RoyaltyInfo(receiver, feeNumerator);
    }

    /**
     * @dev Removes default royalty information.
     */
    function _deleteDefaultRoyalty() internal virtual {
        delete _defaultRoyaltyInfo;
    }

    /**
     * @dev Sets the royalty information for a specific token id, overriding the global default.
     *
     * Requirements:
     *
     * - `receiver` cannot be the zero address.
     * - `feeNumerator` cannot be greater than the fee denominator.
     */
    function _setTokenRoyalty(
        uint256 tokenId,
        address receiver,
        uint96 feeNumerator
    ) internal virtual {
        require(feeNumerator <= _feeDenominator(), "ERC2981: royalty fee will exceed salePrice");
        require(receiver != address(0), "ERC2981: Invalid parameters");

        _tokenRoyaltyInfo[tokenId] = RoyaltyInfo(receiver, feeNumerator);
    }

    /**
     * @dev Resets royalty information for the token id back to the global default.
     */
    function _resetTokenRoyalty(uint256 tokenId) internal virtual {
        delete _tokenRoyaltyInfo[tokenId];
    }
}

// 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/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/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: contracts/SWAgents.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.22;

/**
░░░░░░░ ░░   ░░  ░░░░░  ░░░░░░   ░░░░░░  ░░     ░░     ░░     ░░  ░░░░░  ░░░░░░  
▒▒      ▒▒   ▒▒ ▒▒   ▒▒ ▒▒   ▒▒ ▒▒    ▒▒ ▒▒     ▒▒     ▒▒     ▒▒ ▒▒   ▒▒ ▒▒   ▒▒ 
▒▒▒▒▒▒▒ ▒▒▒▒▒▒▒ ▒▒▒▒▒▒▒ ▒▒   ▒▒ ▒▒    ▒▒ ▒▒  ▒  ▒▒     ▒▒  ▒  ▒▒ ▒▒▒▒▒▒▒ ▒▒▒▒▒▒  
     ▓▓ ▓▓   ▓▓ ▓▓   ▓▓ ▓▓   ▓▓ ▓▓    ▓▓ ▓▓ ▓▓▓ ▓▓     ▓▓ ▓▓▓ ▓▓ ▓▓   ▓▓ ▓▓   ▓▓ 
███████ ██   ██ ██   ██ ██████   ██████   ███ ███       ███ ███  ██   ██ ██   ██ 
*/

/// @title Shadow War NFT Project
/// @author Maerlin KirienzoETH @patriotsdivision
/// @notice This contract mints Agents (NFTs) for the Shadow War project.
import "erc721a/contracts/extensions/ERC721AQueryable.sol";
import "@limitbreak/creator-token-contracts/contracts/utils/CreatorTokenBase.sol";
import "@limitbreak/creator-token-contracts/contracts/access/OwnableBasic.sol";
import "@openzeppelin/contracts/token/common/ERC2981.sol";

contract SWAgents is OwnableBasic, ERC721AQueryable, CreatorTokenBase, ERC2981 {
    /// @dev Represents the price of each tier.
    struct PriceByTier {
        uint64 tier1;
        uint64 tier2;
        uint64 tier3;
    }

    /// @dev Represent each tier of a supply type.
    struct SupplyType {
        uint24 tier1;
        uint24 tier2;
        uint24 tier3;
    }

    /// @dev Represents the unpacked value of _packedTieredSupplyTypes, all tiers for all supplies.
    struct UnpackedSupplyData {
        /// @dev Global max supply of each tier in the collection.
        uint24 tier1MaxSupply;
        uint24 tier2MaxSupply;
        uint24 tier3MaxSupply;
        /// @dev Current supply of the collection.
        uint24 tier1CurrentSupply;
        uint24 tier2CurrentSupply;
        uint24 tier3CurrentSupply;
    }

    /// @notice Base URI for the Agents' metadata.
    string private _uri;
    /// @notice Suffix for the Agents' metadata URI, typically a file extension.
    string private _uriSuffix = ".json";
    /// @notice URI for the hidden metadata before the reveal.
    string private _hiddenMetadataUri;

    /// @notice Cost to mint an NFT for each tier.
    PriceByTier public tiersCost;

    /// @notice Packed supply data.
    uint144 private _packedTieredSupplyTypes;

    /// @notice Flag indicating if minting is paused.
    bool public paused = true;
    /// @notice Flag indicating if Agents' metadata has been revealed.
    bool public revealed = false;

    /// @notice Mapping to track approved contract operators.
    mapping(address => bool) public approvedOperators;

    /// @dev Emitted when a batch of metadata needs to be updated.
    /// This event is useful for marketplaces that can listen and automatically update
    /// the metadata for tokens within the specified range.
    /// @param fromTokenId The starting token ID of the metadata update batch.
    /// @param toTokenId The ending token ID of the metadata update batch.
    event BatchMetadataUpdate(uint256 fromTokenId, uint256 toTokenId);

    /// @notice Constructs the SWAgents contract.
    /// @param _name Name of the ERC721 token.
    /// @param _symbol Symbol of the ERC721 token.
    /// @param _tiersCost Cost to mint an Agent per tier.
    /// @param _tiersMaxSupply Maximum supply of Agents that can be minted per tier.
    constructor(
        string memory _name,
        string memory _symbol,
        PriceByTier memory _tiersCost,
        SupplyType memory _tiersMaxSupply
    ) CreatorTokenBase() ERC721A(_name, _symbol) {
        tiersCost = _tiersCost;
        _packedTieredSupplyTypes = _packAllSupplyTypes(
            _packSupplyTypeData(
                _tiersMaxSupply.tier1,
                _tiersMaxSupply.tier2,
                _tiersMaxSupply.tier3
            ),
            _packSupplyTypeData(0, 0, 0)
        );
        _setDefaultRoyalty(msg.sender, 500);
    }

    /// @dev Pack the data of every tier in a uint72 value.
    function _packSupplyTypeData(
        uint24 _tier1,
        uint24 _tier2,
        uint24 _tier3
    ) private pure returns (uint72) {
        return (uint72(_tier1) << 48) | (uint72(_tier2) << 24) | uint72(_tier3);
    }

    /// @dev Pack the data of every supply type in a uint144 value.
    function _packAllSupplyTypes(
        uint72 _maxSupplyPerTier,
        uint72 _currentSupplyPerTier
    ) private pure returns (uint144) {
        return
            (uint144(_maxSupplyPerTier) << 72) |
            uint144(_currentSupplyPerTier);
    }

    /// @notice Returns the data for all tiers of all supply types.
    /// @dev Unpack _packedTieredSupplyTypes which consists of 9 uint24 values packed together.
    function _getAllSupplyData()
        private
        view
        returns (UnpackedSupplyData memory)
    {
        uint144 _packedData = _packedTieredSupplyTypes;
        return
            UnpackedSupplyData(
                uint24(_packedData >> 120),
                uint24(_packedData >> 96),
                uint24(_packedData >> 72),
                uint24(_packedData >> 48),
                uint24(_packedData >> 24),
                uint24(_packedData)
            );
    }

    /// @notice Mints the specified amount of Agents.
    /// @param _amountForTier1 The number of Agents to be minted in tier 1.
    /// @param _amountForTier2 The number of Agents to be minted in tier 2.
    /// @param _amountForTier3 The number of Agents to be minted in tier 3.
    /// @param _to The address that will receive the NFTs.
    function mint(
        uint16 _amountForTier1,
        uint16 _amountForTier2,
        uint16 _amountForTier3,
        address _to
    ) public payable {
        require(!paused, "The contract is paused!");
        require(
            msg.value ==
                _calculateCost(
                    _amountForTier1,
                    _amountForTier2,
                    _amountForTier3
                ),
            "Incorrect funds!"
        );

        _updateSupplyByTier(
            _amountForTier1,
            _amountForTier2,
            _amountForTier3
        );

        _safeMint(_to, _amountForTier1 + _amountForTier2 + _amountForTier3);
    }

    /// @notice Mint tokens for a specific address without constraints.
    /// @param _amountForTier1 The number of Agents to be minted in tier 1.
    /// @param _amountForTier2 The number of Agents to be minted in tier 2.
    /// @param _amountForTier3 The number of Agents to be minted in tier 3.
    /// @param _to The address to mint tokens to.
    function mintForAddress(
        uint16 _amountForTier1,
        uint16 _amountForTier2,
        uint16 _amountForTier3,
        address _to
    ) public onlyOwner {
        _updateSupplyByTier(
            _amountForTier1,
            _amountForTier2,
            _amountForTier3
        );
        _safeMint(_to, _amountForTier1 + _amountForTier2 + _amountForTier3);
    }

    /// @dev Return the cost of the mint for the provided amount of tiers.
    function _calculateCost(
        uint16 _amountForTier1,
        uint16 _amountForTier2,
        uint16 _amountForTier3
    ) private view returns (uint256) {
        PriceByTier memory _tiersCost = tiersCost;
        return
            (_tiersCost.tier1 * _amountForTier1) +
            (_tiersCost.tier2 * _amountForTier2) +
            (_tiersCost.tier3 * _amountForTier3);
    }

    /// @dev Check and update the supply for each tier.
    function _updateSupplyByTier(
        uint16 _amountForTier1,
        uint16 _amountForTier2,
        uint16 _amountForTier3
    ) private {
        UnpackedSupplyData memory _unpackedSupplyData = _getAllSupplyData();

        // Should be safe from overflow attack because storage supply is uint24 and parameters are uint16
        unchecked {
            _unpackedSupplyData.tier1CurrentSupply += _amountForTier1;
            _unpackedSupplyData.tier2CurrentSupply += _amountForTier2;
            _unpackedSupplyData.tier3CurrentSupply += _amountForTier3;

            require(
                _unpackedSupplyData.tier1CurrentSupply <=
                    _unpackedSupplyData.tier1MaxSupply &&
                    _unpackedSupplyData.tier2CurrentSupply <=
                    _unpackedSupplyData.tier2MaxSupply &&
                    _unpackedSupplyData.tier3CurrentSupply <=
                    _unpackedSupplyData.tier3MaxSupply,
                "Max supply for tier exceeded"
            );

            _packedTieredSupplyTypes = _packAllSupplyTypes(
                _packSupplyTypeData(
                    _unpackedSupplyData.tier1MaxSupply,
                    _unpackedSupplyData.tier2MaxSupply,
                    _unpackedSupplyData.tier3MaxSupply
                ),
                _packSupplyTypeData(
                    _unpackedSupplyData.tier1CurrentSupply,
                    _unpackedSupplyData.tier2CurrentSupply,
                    _unpackedSupplyData.tier3CurrentSupply
                )
            );
        }
    }

    /// @notice Returns the max supply for each tier.
    function maxTiersSupply() external view returns (SupplyType memory) {
        UnpackedSupplyData memory _packedSupplyByTiers = _getAllSupplyData();
        return
            SupplyType(
                _packedSupplyByTiers.tier1MaxSupply,
                _packedSupplyByTiers.tier2MaxSupply,
                _packedSupplyByTiers.tier3MaxSupply
            );
    }

    /// @notice Returns the current supply in each tier.
    function tiersCurrentSupply() external view returns (SupplyType memory) {
        UnpackedSupplyData memory _packedSupplyByTiers = _getAllSupplyData();
        return
            SupplyType(
                _packedSupplyByTiers.tier1CurrentSupply,
                _packedSupplyByTiers.tier2CurrentSupply,
                _packedSupplyByTiers.tier3CurrentSupply
            );
    }

    /// @notice Returns the Token URI with Metadata for specified Token Id.
    /// @param _tokenId The Token Id to query.
    /// @return The URI string of the specified Token Id.
    function tokenURI(
        uint256 _tokenId
    ) public view override(ERC721A, IERC721A) returns (string memory) {
        require(
            _exists(_tokenId),
            "ERC721Metadata: URI query for nonexistent token"
        );

        if (revealed == false) {
            return _hiddenMetadataUri;
        }

        string memory _currentBaseURI = _baseURI();
        return
            bytes(_currentBaseURI).length > 0
                ? string(
                    abi.encodePacked(
                        _currentBaseURI,
                        _toString(_tokenId),
                        _uriSuffix
                    )
                )
                : "";
    }

    /// @notice Returns the Base URI without the suffix for specified Token Id.
    /// @return The URI string of the specified Token Id.
    function _baseURI() internal view override returns (string memory) {
        return _uri;
    }

    /// @notice Update the revealed state of the contract.
    /// @dev This function can only be called by the contract owner.
    /// @param _state The new desired revealed state. If `true`, it means the metadata
    /// for the tokens have been revealed and should be visible.
    function setRevealed(bool _state) public onlyOwner {
        revealed = _state;

        emit BatchMetadataUpdate(0, type(uint256).max);
    }

    /// @notice Check if an address is approved to operate on behalf of the owner.
    /// @param _owner The owner's address.
    /// @param operator The operator's address to check.
    /// @return Whether the operator is approved.
    function isApprovedForAll(
        address _owner,
        address operator
    ) public view override(ERC721A, IERC721A) returns (bool) {
        // If operator is in pre-approved list, return true
        if (approvedOperators[operator]) return true;

        return super.isApprovedForAll(_owner, operator);
    }

    /// @notice Set the hidden metadata URI.
    /// @param _newHiddenMetadataUri The new hidden metadata URI.
    function setHiddenMetadataUri(
        string calldata _newHiddenMetadataUri
    ) public onlyOwner {
        _hiddenMetadataUri = _newHiddenMetadataUri;
    }

    /// @notice Set the base URI for token metadata.
    /// @param _newUri The new base URI.
    function setUri(string calldata _newUri) public onlyOwner {
        _uri = _newUri;
    }

    /// @notice Set the URI suffix for token metadata.
    /// @param _newUriSuffix The new URI suffix.
    function setUriSuffix(string calldata _newUriSuffix) public onlyOwner {
        _uriSuffix = _newUriSuffix;
    }

    /// @notice Pause or unpause the contract.
    /// @param _state The new pause state.
    function setPaused(bool _state) public onlyOwner {
        paused = _state;
    }

    /// @notice Set a new price for each tier.
    /// @param _tier1Price New price for tier1.
    /// @param _tier2Price New price for tier2.
    /// @param _tier3Price New price for tier3.
    function setPrices(
        uint64 _tier1Price,
        uint64 _tier2Price,
        uint64 _tier3Price
    ) public onlyOwner {
        tiersCost = PriceByTier(_tier1Price, _tier2Price, _tier3Price);
    }

    /// @notice Withdraws the ETH from the contract to the owner.
    function withdraw() public onlyOwner {
        (bool success, ) = owner().call{value: address(this).balance}("");
        require(success);
    }

    /// @notice Add an address to the list of approved operators.
    /// @param _address The address to add.
    function addApprovedOperator(address _address) external onlyOwner {
        approvedOperators[_address] = true;
    }

    /// @notice Remove an address from the list of approved operators.
    /// @param _address The address to remove.
    function removeApprovedOperator(address _address) external onlyOwner {
        approvedOperators[_address] = false;
    }

    /// @dev See {IERC165-supportsInterface}.
    function supportsInterface(
        bytes4 interfaceId
    ) public view override(ERC721A, IERC721A, ERC2981) returns (bool) {
        return
            interfaceId == type(ICreatorToken).interfaceId ||
            interfaceId == type(IERC2981).interfaceId ||
            ERC721A.supportsInterface(interfaceId);
    }

    /// @dev Set the royalty receiver and fee
    function setDefaultRoyalty(
        address receiver,
        uint96 fee
    ) external onlyOwner {
        _setDefaultRoyalty(receiver, fee);
    }

    ////////////////////////////////////////////////////////////////////////////////////////////////////////////
    //////////////////////////////////////// ERC721C specific functions ////////////////////////////////////////
    ////////////////////////////////////////////////////////////////////////////////////////////////////////////

    /// @dev Ties the erc721a _beforeTokenTransfers hook to more granular transfer validation logic
    function _beforeTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal override {
        unchecked {
            for (uint256 i = 0; i < quantity; ++i) {
                _validateBeforeTransfer(from, to, startTokenId + i);
            }
        }
    }

    /// @dev Ties the erc721a _afterTokenTransfer hook to more granular transfer validation logic
    function _afterTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal override {
        unchecked {
            for (uint256 i = 0; i < quantity; ++i) {
                _validateAfterTransfer(from, to, startTokenId + i);
            }
        }
    }
}

// File: erc721a/contracts/ERC721A.sol



// SPDX-License-Identifier: MIT
// ERC721A Contracts v4.2.3
// Creator: Chiru Labs

pragma solidity ^0.8.4;

import './IERC721A.sol';

/**
 * @dev Interface of ERC721 token receiver.
 */
interface ERC721A__IERC721Receiver {
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

/**
 * @title ERC721A
 *
 * @dev Implementation of the [ERC721](https://eips.ethereum.org/EIPS/eip-721)
 * Non-Fungible Token Standard, including the Metadata extension.
 * Optimized for lower gas during batch mints.
 *
 * Token IDs are minted in sequential order (e.g. 0, 1, 2, 3, ...)
 * starting from `_startTokenId()`.
 *
 * Assumptions:
 *
 * - An owner cannot have more than 2**64 - 1 (max value of uint64) of supply.
 * - The maximum token ID cannot exceed 2**256 - 1 (max value of uint256).
 */
contract ERC721A is IERC721A {
    // Bypass for a `--via-ir` bug (https://github.com/chiru-labs/ERC721A/pull/364).
    struct TokenApprovalRef {
        address value;
    }

    // =============================================================
    //                           CONSTANTS
    // =============================================================

    // Mask of an entry in packed address data.
    uint256 private constant _BITMASK_ADDRESS_DATA_ENTRY = (1 << 64) - 1;

    // The bit position of `numberMinted` in packed address data.
    uint256 private constant _BITPOS_NUMBER_MINTED = 64;

    // The bit position of `numberBurned` in packed address data.
    uint256 private constant _BITPOS_NUMBER_BURNED = 128;

    // The bit position of `aux` in packed address data.
    uint256 private constant _BITPOS_AUX = 192;

    // Mask of all 256 bits in packed address data except the 64 bits for `aux`.
    uint256 private constant _BITMASK_AUX_COMPLEMENT = (1 << 192) - 1;

    // The bit position of `startTimestamp` in packed ownership.
    uint256 private constant _BITPOS_START_TIMESTAMP = 160;

    // The bit mask of the `burned` bit in packed ownership.
    uint256 private constant _BITMASK_BURNED = 1 << 224;

    // The bit position of the `nextInitialized` bit in packed ownership.
    uint256 private constant _BITPOS_NEXT_INITIALIZED = 225;

    // The bit mask of the `nextInitialized` bit in packed ownership.
    uint256 private constant _BITMASK_NEXT_INITIALIZED = 1 << 225;

    // The bit position of `extraData` in packed ownership.
    uint256 private constant _BITPOS_EXTRA_DATA = 232;

    // Mask of all 256 bits in a packed ownership except the 24 bits for `extraData`.
    uint256 private constant _BITMASK_EXTRA_DATA_COMPLEMENT = (1 << 232) - 1;

    // The mask of the lower 160 bits for addresses.
    uint256 private constant _BITMASK_ADDRESS = (1 << 160) - 1;

    // The maximum `quantity` that can be minted with {_mintERC2309}.
    // This limit is to prevent overflows on the address data entries.
    // For a limit of 5000, a total of 3.689e15 calls to {_mintERC2309}
    // is required to cause an overflow, which is unrealistic.
    uint256 private constant _MAX_MINT_ERC2309_QUANTITY_LIMIT = 5000;

    // The `Transfer` event signature is given by:
    // `keccak256(bytes("Transfer(address,address,uint256)"))`.
    bytes32 private constant _TRANSFER_EVENT_SIGNATURE =
        0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef;

    // =============================================================
    //                            STORAGE
    // =============================================================

    // The next token ID to be minted.
    uint256 private _currentIndex;

    // The number of tokens burned.
    uint256 private _burnCounter;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Mapping from token ID to ownership details
    // An empty struct value does not necessarily mean the token is unowned.
    // See {_packedOwnershipOf} implementation for details.
    //
    // Bits Layout:
    // - [0..159]   `addr`
    // - [160..223] `startTimestamp`
    // - [224]      `burned`
    // - [225]      `nextInitialized`
    // - [232..255] `extraData`
    mapping(uint256 => uint256) private _packedOwnerships;

    // Mapping owner address to address data.
    //
    // Bits Layout:
    // - [0..63]    `balance`
    // - [64..127]  `numberMinted`
    // - [128..191] `numberBurned`
    // - [192..255] `aux`
    mapping(address => uint256) private _packedAddressData;

    // Mapping from token ID to approved address.
    mapping(uint256 => TokenApprovalRef) private _tokenApprovals;

    // Mapping from owner to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    // =============================================================
    //                          CONSTRUCTOR
    // =============================================================

    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
        _currentIndex = _startTokenId();
    }

    // =============================================================
    //                   TOKEN COUNTING OPERATIONS
    // =============================================================

    /**
     * @dev Returns the starting token ID.
     * To change the starting token ID, please override this function.
     */
    function _startTokenId() internal view virtual returns (uint256) {
        return 0;
    }

    /**
     * @dev Returns the next token ID to be minted.
     */
    function _nextTokenId() internal view virtual returns (uint256) {
        return _currentIndex;
    }

    /**
     * @dev Returns the total number of tokens in existence.
     * Burned tokens will reduce the count.
     * To get the total number of tokens minted, please see {_totalMinted}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        // Counter underflow is impossible as _burnCounter cannot be incremented
        // more than `_currentIndex - _startTokenId()` times.
        unchecked {
            return _currentIndex - _burnCounter - _startTokenId();
        }
    }

    /**
     * @dev Returns the total amount of tokens minted in the contract.
     */
    function _totalMinted() internal view virtual returns (uint256) {
        // Counter underflow is impossible as `_currentIndex` does not decrement,
        // and it is initialized to `_startTokenId()`.
        unchecked {
            return _currentIndex - _startTokenId();
        }
    }

    /**
     * @dev Returns the total number of tokens burned.
     */
    function _totalBurned() internal view virtual returns (uint256) {
        return _burnCounter;
    }

    // =============================================================
    //                    ADDRESS DATA OPERATIONS
    // =============================================================

    /**
     * @dev Returns the number of tokens in `owner`'s account.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        if (owner == address(0)) revert BalanceQueryForZeroAddress();
        return _packedAddressData[owner] & _BITMASK_ADDRESS_DATA_ENTRY;
    }

    /**
     * Returns the number of tokens minted by `owner`.
     */
    function _numberMinted(address owner) internal view returns (uint256) {
        return (_packedAddressData[owner] >> _BITPOS_NUMBER_MINTED) & _BITMASK_ADDRESS_DATA_ENTRY;
    }

    /**
     * Returns the number of tokens burned by or on behalf of `owner`.
     */
    function _numberBurned(address owner) internal view returns (uint256) {
        return (_packedAddressData[owner] >> _BITPOS_NUMBER_BURNED) & _BITMASK_ADDRESS_DATA_ENTRY;
    }

    /**
     * Returns the auxiliary data for `owner`. (e.g. number of whitelist mint slots used).
     */
    function _getAux(address owner) internal view returns (uint64) {
        return uint64(_packedAddressData[owner] >> _BITPOS_AUX);
    }

    /**
     * Sets the auxiliary data for `owner`. (e.g. number of whitelist mint slots used).
     * If there are multiple variables, please pack them into a uint64.
     */
    function _setAux(address owner, uint64 aux) internal virtual {
        uint256 packed = _packedAddressData[owner];
        uint256 auxCasted;
        // Cast `aux` with assembly to avoid redundant masking.
        assembly {
            auxCasted := aux
        }
        packed = (packed & _BITMASK_AUX_COMPLEMENT) | (auxCasted << _BITPOS_AUX);
        _packedAddressData[owner] = packed;
    }

    // =============================================================
    //                            IERC165
    // =============================================================

    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * [EIP section](https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified)
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30000 gas.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        // The interface IDs are constants representing the first 4 bytes
        // of the XOR of all function selectors in the interface.
        // See: [ERC165](https://eips.ethereum.org/EIPS/eip-165)
        // (e.g. `bytes4(i.functionA.selector ^ i.functionB.selector ^ ...)`)
        return
            interfaceId == 0x01ffc9a7 || // ERC165 interface ID for ERC165.
            interfaceId == 0x80ac58cd || // ERC165 interface ID for ERC721.
            interfaceId == 0x5b5e139f; // ERC165 interface ID for ERC721Metadata.
    }

    // =============================================================
    //                        IERC721Metadata
    // =============================================================

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

    /**
     * @dev Returns the token collection symbol.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        if (!_exists(tokenId)) revert URIQueryForNonexistentToken();

        string memory baseURI = _baseURI();
        return bytes(baseURI).length != 0 ? string(abi.encodePacked(baseURI, _toString(tokenId))) : '';
    }

    /**
     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
     * by default, it can be overridden in child contracts.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return '';
    }

    // =============================================================
    //                     OWNERSHIPS OPERATIONS
    // =============================================================

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        return address(uint160(_packedOwnershipOf(tokenId)));
    }

    /**
     * @dev Gas spent here starts off proportional to the maximum mint batch size.
     * It gradually moves to O(1) as tokens get transferred around over time.
     */
    function _ownershipOf(uint256 tokenId) internal view virtual returns (TokenOwnership memory) {
        return _unpackedOwnership(_packedOwnershipOf(tokenId));
    }

    /**
     * @dev Returns the unpacked `TokenOwnership` struct at `index`.
     */
    function _ownershipAt(uint256 index) internal view virtual returns (TokenOwnership memory) {
        return _unpackedOwnership(_packedOwnerships[index]);
    }

    /**
     * @dev Initializes the ownership slot minted at `index` for efficiency purposes.
     */
    function _initializeOwnershipAt(uint256 index) internal virtual {
        if (_packedOwnerships[index] == 0) {
            _packedOwnerships[index] = _packedOwnershipOf(index);
        }
    }

    /**
     * Returns the packed ownership data of `tokenId`.
     */
    function _packedOwnershipOf(uint256 tokenId) private view returns (uint256) {
        uint256 curr = tokenId;

        unchecked {
            if (_startTokenId() <= curr)
                if (curr < _currentIndex) {
                    uint256 packed = _packedOwnerships[curr];
                    // If not burned.
                    if (packed & _BITMASK_BURNED == 0) {
                        // Invariant:
                        // There will always be an initialized ownership slot
                        // (i.e. `ownership.addr != address(0) && ownership.burned == false`)
                        // before an unintialized ownership slot
                        // (i.e. `ownership.addr == address(0) && ownership.burned == false`)
                        // Hence, `curr` will not underflow.
                        //
                        // We can directly compare the packed value.
                        // If the address is zero, packed will be zero.
                        while (packed == 0) {
                            packed = _packedOwnerships[--curr];
                        }
                        return packed;
                    }
                }
        }
        revert OwnerQueryForNonexistentToken();
    }

    /**
     * @dev Returns the unpacked `TokenOwnership` struct from `packed`.
     */
    function _unpackedOwnership(uint256 packed) private pure returns (TokenOwnership memory ownership) {
        ownership.addr = address(uint160(packed));
        ownership.startTimestamp = uint64(packed >> _BITPOS_START_TIMESTAMP);
        ownership.burned = packed & _BITMASK_BURNED != 0;
        ownership.extraData = uint24(packed >> _BITPOS_EXTRA_DATA);
    }

    /**
     * @dev Packs ownership data into a single uint256.
     */
    function _packOwnershipData(address owner, uint256 flags) private view returns (uint256 result) {
        assembly {
            // Mask `owner` to the lower 160 bits, in case the upper bits somehow aren't clean.
            owner := and(owner, _BITMASK_ADDRESS)
            // `owner | (block.timestamp << _BITPOS_START_TIMESTAMP) | flags`.
            result := or(owner, or(shl(_BITPOS_START_TIMESTAMP, timestamp()), flags))
        }
    }

    /**
     * @dev Returns the `nextInitialized` flag set if `quantity` equals 1.
     */
    function _nextInitializedFlag(uint256 quantity) private pure returns (uint256 result) {
        // For branchless setting of the `nextInitialized` flag.
        assembly {
            // `(quantity == 1) << _BITPOS_NEXT_INITIALIZED`.
            result := shl(_BITPOS_NEXT_INITIALIZED, eq(quantity, 1))
        }
    }

    // =============================================================
    //                      APPROVAL OPERATIONS
    // =============================================================

    /**
     * @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) public payable virtual override {
        address owner = ownerOf(tokenId);

        if (_msgSenderERC721A() != owner)
            if (!isApprovedForAll(owner, _msgSenderERC721A())) {
                revert ApprovalCallerNotOwnerNorApproved();
            }

        _tokenApprovals[tokenId].value = to;
        emit Approval(owner, to, tokenId);
    }

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();

        return _tokenApprovals[tokenId].value;
    }

    /**
     * @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) public virtual override {
        _operatorApprovals[_msgSenderERC721A()][operator] = approved;
        emit ApprovalForAll(_msgSenderERC721A(), operator, approved);
    }

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

    /**
     * @dev Returns whether `tokenId` exists.
     *
     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
     *
     * Tokens start existing when they are minted. See {_mint}.
     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return
            _startTokenId() <= tokenId &&
            tokenId < _currentIndex && // If within bounds,
            _packedOwnerships[tokenId] & _BITMASK_BURNED == 0; // and not burned.
    }

    /**
     * @dev Returns whether `msgSender` is equal to `approvedAddress` or `owner`.
     */
    function _isSenderApprovedOrOwner(
        address approvedAddress,
        address owner,
        address msgSender
    ) private pure returns (bool result) {
        assembly {
            // Mask `owner` to the lower 160 bits, in case the upper bits somehow aren't clean.
            owner := and(owner, _BITMASK_ADDRESS)
            // Mask `msgSender` to the lower 160 bits, in case the upper bits somehow aren't clean.
            msgSender := and(msgSender, _BITMASK_ADDRESS)
            // `msgSender == owner || msgSender == approvedAddress`.
            result := or(eq(msgSender, owner), eq(msgSender, approvedAddress))
        }
    }

    /**
     * @dev Returns the storage slot and value for the approved address of `tokenId`.
     */
    function _getApprovedSlotAndAddress(uint256 tokenId)
        private
        view
        returns (uint256 approvedAddressSlot, address approvedAddress)
    {
        TokenApprovalRef storage tokenApproval = _tokenApprovals[tokenId];
        // The following is equivalent to `approvedAddress = _tokenApprovals[tokenId].value`.
        assembly {
            approvedAddressSlot := tokenApproval.slot
            approvedAddress := sload(approvedAddressSlot)
        }
    }

    // =============================================================
    //                      TRANSFER OPERATIONS
    // =============================================================

    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *
     * 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
    ) public payable virtual override {
        uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);

        if (address(uint160(prevOwnershipPacked)) != from) revert TransferFromIncorrectOwner();

        (uint256 approvedAddressSlot, address approvedAddress) = _getApprovedSlotAndAddress(tokenId);

        // The nested ifs save around 20+ gas over a compound boolean condition.
        if (!_isSenderApprovedOrOwner(approvedAddress, from, _msgSenderERC721A()))
            if (!isApprovedForAll(from, _msgSenderERC721A())) revert TransferCallerNotOwnerNorApproved();

        if (to == address(0)) revert TransferToZeroAddress();

        _beforeTokenTransfers(from, to, tokenId, 1);

        // Clear approvals from the previous owner.
        assembly {
            if approvedAddress {
                // This is equivalent to `delete _tokenApprovals[tokenId]`.
                sstore(approvedAddressSlot, 0)
            }
        }

        // Underflow of the sender's balance is impossible because we check for
        // ownership above and the recipient's balance can't realistically overflow.
        // Counter overflow is incredibly unrealistic as `tokenId` would have to be 2**256.
        unchecked {
            // We can directly increment and decrement the balances.
            --_packedAddressData[from]; // Updates: `balance -= 1`.
            ++_packedAddressData[to]; // Updates: `balance += 1`.

            // Updates:
            // - `address` to the next owner.
            // - `startTimestamp` to the timestamp of transfering.
            // - `burned` to `false`.
            // - `nextInitialized` to `true`.
            _packedOwnerships[tokenId] = _packOwnershipData(
                to,
                _BITMASK_NEXT_INITIALIZED | _nextExtraData(from, to, prevOwnershipPacked)
            );

            // If the next slot may not have been initialized (i.e. `nextInitialized == false`) .
            if (prevOwnershipPacked & _BITMASK_NEXT_INITIALIZED == 0) {
                uint256 nextTokenId = tokenId + 1;
                // If the next slot's address is zero and not burned (i.e. packed value is zero).
                if (_packedOwnerships[nextTokenId] == 0) {
                    // If the next slot is within bounds.
                    if (nextTokenId != _currentIndex) {
                        // Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.
                        _packedOwnerships[nextTokenId] = prevOwnershipPacked;
                    }
                }
            }
        }

        emit Transfer(from, to, tokenId);
        _afterTokenTransfers(from, to, tokenId, 1);
    }

    /**
     * @dev Equivalent to `safeTransferFrom(from, to, tokenId, '')`.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public payable virtual override {
        safeTransferFrom(from, to, tokenId, '');
    }

    /**
     * @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 memory _data
    ) public payable virtual override {
        transferFrom(from, to, tokenId);
        if (to.code.length != 0)
            if (!_checkContractOnERC721Received(from, to, tokenId, _data)) {
                revert TransferToNonERC721ReceiverImplementer();
            }
    }

    /**
     * @dev Hook that is called before a set of serially-ordered token IDs
     * are about to be transferred. This includes minting.
     * And also called before burning one token.
     *
     * `startTokenId` - the first token ID to be transferred.
     * `quantity` - the amount to be transferred.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, `from`'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, `tokenId` will be burned by `from`.
     * - `from` and `to` are never both zero.
     */
    function _beforeTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual {}

    /**
     * @dev Hook that is called after a set of serially-ordered token IDs
     * have been transferred. This includes minting.
     * And also called after one token has been burned.
     *
     * `startTokenId` - the first token ID to be transferred.
     * `quantity` - the amount to be transferred.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, `from`'s `tokenId` has been
     * transferred to `to`.
     * - When `from` is zero, `tokenId` has been minted for `to`.
     * - When `to` is zero, `tokenId` has been burned by `from`.
     * - `from` and `to` are never both zero.
     */
    function _afterTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual {}

    /**
     * @dev Private function to invoke {IERC721Receiver-onERC721Received} on a target contract.
     *
     * `from` - Previous owner of the given token ID.
     * `to` - Target address that will receive the token.
     * `tokenId` - Token ID to be transferred.
     * `_data` - Optional data to send along with the call.
     *
     * Returns whether the call correctly returned the expected magic value.
     */
    function _checkContractOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) private returns (bool) {
        try ERC721A__IERC721Receiver(to).onERC721Received(_msgSenderERC721A(), from, tokenId, _data) returns (
            bytes4 retval
        ) {
            return retval == ERC721A__IERC721Receiver(to).onERC721Received.selector;
        } catch (bytes memory reason) {
            if (reason.length == 0) {
                revert TransferToNonERC721ReceiverImplementer();
            } else {
                assembly {
                    revert(add(32, reason), mload(reason))
                }
            }
        }
    }

    // =============================================================
    //                        MINT OPERATIONS
    // =============================================================

    /**
     * @dev Mints `quantity` tokens and transfers them to `to`.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `quantity` must be greater than 0.
     *
     * Emits a {Transfer} event for each mint.
     */
    function _mint(address to, uint256 quantity) internal virtual {
        uint256 startTokenId = _currentIndex;
        if (quantity == 0) revert MintZeroQuantity();

        _beforeTokenTransfers(address(0), to, startTokenId, quantity);

        // Overflows are incredibly unrealistic.
        // `balance` and `numberMinted` have a maximum limit of 2**64.
        // `tokenId` has a maximum limit of 2**256.
        unchecked {
            // Updates:
            // - `balance += quantity`.
            // - `numberMinted += quantity`.
            //
            // We can directly add to the `balance` and `numberMinted`.
            _packedAddressData[to] += quantity * ((1 << _BITPOS_NUMBER_MINTED) | 1);

            // Updates:
            // - `address` to the owner.
            // - `startTimestamp` to the timestamp of minting.
            // - `burned` to `false`.
            // - `nextInitialized` to `quantity == 1`.
            _packedOwnerships[startTokenId] = _packOwnershipData(
                to,
                _nextInitializedFlag(quantity) | _nextExtraData(address(0), to, 0)
            );

            uint256 toMasked;
            uint256 end = startTokenId + quantity;

            // Use assembly to loop and emit the `Transfer` event for gas savings.
            // The duplicated `log4` removes an extra check and reduces stack juggling.
            // The assembly, together with the surrounding Solidity code, have been
            // delicately arranged to nudge the compiler into producing optimized opcodes.
            assembly {
                // Mask `to` to the lower 160 bits, in case the upper bits somehow aren't clean.
                toMasked := and(to, _BITMASK_ADDRESS)
                // Emit the `Transfer` event.
                log4(
                    0, // Start of data (0, since no data).
                    0, // End of data (0, since no data).
                    _TRANSFER_EVENT_SIGNATURE, // Signature.
                    0, // `address(0)`.
                    toMasked, // `to`.
                    startTokenId // `tokenId`.
                )

                // The `iszero(eq(,))` check ensures that large values of `quantity`
                // that overflows uint256 will make the loop run out of gas.
                // The compiler will optimize the `iszero` away for performance.
                for {
                    let tokenId := add(startTokenId, 1)
                } iszero(eq(tokenId, end)) {
                    tokenId := add(tokenId, 1)
                } {
                    // Emit the `Transfer` event. Similar to above.
                    log4(0, 0, _TRANSFER_EVENT_SIGNATURE, 0, toMasked, tokenId)
                }
            }
            if (toMasked == 0) revert MintToZeroAddress();

            _currentIndex = end;
        }
        _afterTokenTransfers(address(0), to, startTokenId, quantity);
    }

    /**
     * @dev Mints `quantity` tokens and transfers them to `to`.
     *
     * This function is intended for efficient minting only during contract creation.
     *
     * It emits only one {ConsecutiveTransfer} as defined in
     * [ERC2309](https://eips.ethereum.org/EIPS/eip-2309),
     * instead of a sequence of {Transfer} event(s).
     *
     * Calling this function outside of contract creation WILL make your contract
     * non-compliant with the ERC721 standard.
     * For full ERC721 compliance, substituting ERC721 {Transfer} event(s) with the ERC2309
     * {ConsecutiveTransfer} event is only permissible during contract creation.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `quantity` must be greater than 0.
     *
     * Emits a {ConsecutiveTransfer} event.
     */
    function _mintERC2309(address to, uint256 quantity) internal virtual {
        uint256 startTokenId = _currentIndex;
        if (to == address(0)) revert MintToZeroAddress();
        if (quantity == 0) revert MintZeroQuantity();
        if (quantity > _MAX_MINT_ERC2309_QUANTITY_LIMIT) revert MintERC2309QuantityExceedsLimit();

        _beforeTokenTransfers(address(0), to, startTokenId, quantity);

        // Overflows are unrealistic due to the above check for `quantity` to be below the limit.
        unchecked {
            // Updates:
            // - `balance += quantity`.
            // - `numberMinted += quantity`.
            //
            // We can directly add to the `balance` and `numberMinted`.
            _packedAddressData[to] += quantity * ((1 << _BITPOS_NUMBER_MINTED) | 1);

            // Updates:
            // - `address` to the owner.
            // - `startTimestamp` to the timestamp of minting.
            // - `burned` to `false`.
            // - `nextInitialized` to `quantity == 1`.
            _packedOwnerships[startTokenId] = _packOwnershipData(
                to,
                _nextInitializedFlag(quantity) | _nextExtraData(address(0), to, 0)
            );

            emit ConsecutiveTransfer(startTokenId, startTokenId + quantity - 1, address(0), to);

            _currentIndex = startTokenId + quantity;
        }
        _afterTokenTransfers(address(0), to, startTokenId, quantity);
    }

    /**
     * @dev Safely mints `quantity` tokens and transfers them to `to`.
     *
     * Requirements:
     *
     * - If `to` refers to a smart contract, it must implement
     * {IERC721Receiver-onERC721Received}, which is called for each safe transfer.
     * - `quantity` must be greater than 0.
     *
     * See {_mint}.
     *
     * Emits a {Transfer} event for each mint.
     */
    function _safeMint(
        address to,
        uint256 quantity,
        bytes memory _data
    ) internal virtual {
        _mint(to, quantity);

        unchecked {
            if (to.code.length != 0) {
                uint256 end = _currentIndex;
                uint256 index = end - quantity;
                do {
                    if (!_checkContractOnERC721Received(address(0), to, index++, _data)) {
                        revert TransferToNonERC721ReceiverImplementer();
                    }
                } while (index < end);
                // Reentrancy protection.
                if (_currentIndex != end) revert();
            }
        }
    }

    /**
     * @dev Equivalent to `_safeMint(to, quantity, '')`.
     */
    function _safeMint(address to, uint256 quantity) internal virtual {
        _safeMint(to, quantity, '');
    }

    // =============================================================
    //                        BURN OPERATIONS
    // =============================================================

    /**
     * @dev Equivalent to `_burn(tokenId, false)`.
     */
    function _burn(uint256 tokenId) internal virtual {
        _burn(tokenId, false);
    }

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId, bool approvalCheck) internal virtual {
        uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);

        address from = address(uint160(prevOwnershipPacked));

        (uint256 approvedAddressSlot, address approvedAddress) = _getApprovedSlotAndAddress(tokenId);

        if (approvalCheck) {
            // The nested ifs save around 20+ gas over a compound boolean condition.
            if (!_isSenderApprovedOrOwner(approvedAddress, from, _msgSenderERC721A()))
                if (!isApprovedForAll(from, _msgSenderERC721A())) revert TransferCallerNotOwnerNorApproved();
        }

        _beforeTokenTransfers(from, address(0), tokenId, 1);

        // Clear approvals from the previous owner.
        assembly {
            if approvedAddress {
                // This is equivalent to `delete _tokenApprovals[tokenId]`.
                sstore(approvedAddressSlot, 0)
            }
        }

        // Underflow of the sender's balance is impossible because we check for
        // ownership above and the recipient's balance can't realistically overflow.
        // Counter overflow is incredibly unrealistic as `tokenId` would have to be 2**256.
        unchecked {
            // Updates:
            // - `balance -= 1`.
            // - `numberBurned += 1`.
            //
            // We can directly decrement the balance, and increment the number burned.
            // This is equivalent to `packed -= 1; packed += 1 << _BITPOS_NUMBER_BURNED;`.
            _packedAddressData[from] += (1 << _BITPOS_NUMBER_BURNED) - 1;

            // Updates:
            // - `address` to the last owner.
            // - `startTimestamp` to the timestamp of burning.
            // - `burned` to `true`.
            // - `nextInitialized` to `true`.
            _packedOwnerships[tokenId] = _packOwnershipData(
                from,
                (_BITMASK_BURNED | _BITMASK_NEXT_INITIALIZED) | _nextExtraData(from, address(0), prevOwnershipPacked)
            );

            // If the next slot may not have been initialized (i.e. `nextInitialized == false`) .
            if (prevOwnershipPacked & _BITMASK_NEXT_INITIALIZED == 0) {
                uint256 nextTokenId = tokenId + 1;
                // If the next slot's address is zero and not burned (i.e. packed value is zero).
                if (_packedOwnerships[nextTokenId] == 0) {
                    // If the next slot is within bounds.
                    if (nextTokenId != _currentIndex) {
                        // Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.
                        _packedOwnerships[nextTokenId] = prevOwnershipPacked;
                    }
                }
            }
        }

        emit Transfer(from, address(0), tokenId);
        _afterTokenTransfers(from, address(0), tokenId, 1);

        // Overflow not possible, as _burnCounter cannot be exceed _currentIndex times.
        unchecked {
            _burnCounter++;
        }
    }

    // =============================================================
    //                     EXTRA DATA OPERATIONS
    // =============================================================

    /**
     * @dev Directly sets the extra data for the ownership data `index`.
     */
    function _setExtraDataAt(uint256 index, uint24 extraData) internal virtual {
        uint256 packed = _packedOwnerships[index];
        if (packed == 0) revert OwnershipNotInitializedForExtraData();
        uint256 extraDataCasted;
        // Cast `extraData` with assembly to avoid redundant masking.
        assembly {
            extraDataCasted := extraData
        }
        packed = (packed & _BITMASK_EXTRA_DATA_COMPLEMENT) | (extraDataCasted << _BITPOS_EXTRA_DATA);
        _packedOwnerships[index] = packed;
    }

    /**
     * @dev Called during each token transfer to set the 24bit `extraData` field.
     * Intended to be overridden by the cosumer contract.
     *
     * `previousExtraData` - the value of `extraData` before transfer.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, `from`'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, `tokenId` will be burned by `from`.
     * - `from` and `to` are never both zero.
     */
    function _extraData(
        address from,
        address to,
        uint24 previousExtraData
    ) internal view virtual returns (uint24) {}

    /**
     * @dev Returns the next extra data for the packed ownership data.
     * The returned result is shifted into position.
     */
    function _nextExtraData(
        address from,
        address to,
        uint256 prevOwnershipPacked
    ) private view returns (uint256) {
        uint24 extraData = uint24(prevOwnershipPacked >> _BITPOS_EXTRA_DATA);
        return uint256(_extraData(from, to, extraData)) << _BITPOS_EXTRA_DATA;
    }

    // =============================================================
    //                       OTHER OPERATIONS
    // =============================================================

    /**
     * @dev Returns the message sender (defaults to `msg.sender`).
     *
     * If you are writing GSN compatible contracts, you need to override this function.
     */
    function _msgSenderERC721A() internal view virtual returns (address) {
        return msg.sender;
    }

    /**
     * @dev Converts a uint256 to its ASCII string decimal representation.
     */
    function _toString(uint256 value) internal pure virtual returns (string memory str) {
        assembly {
            // The maximum value of a uint256 contains 78 digits (1 byte per digit), but
            // we allocate 0xa0 bytes to keep the free memory pointer 32-byte word aligned.
            // We will need 1 word for the trailing zeros padding, 1 word for the length,
            // and 3 words for a maximum of 78 digits. Total: 5 * 0x20 = 0xa0.
            let m := add(mload(0x40), 0xa0)
            // Update the free memory pointer to allocate.
            mstore(0x40, m)
            // Assign the `str` to the end.
            str := sub(m, 0x20)
            // Zeroize the slot after the string.
            mstore(str, 0)

            // Cache the end of the memory to calculate the length later.
            let end := str

            // We write the string from rightmost digit to leftmost digit.
            // The following is essentially a do-while loop that also handles the zero case.
            // prettier-ignore
            for { let temp := value } 1 {} {
                str := sub(str, 1)
                // Write the character to the pointer.
                // The ASCII index of the '0' character is 48.
                mstore8(str, add(48, mod(temp, 10)))
                // Keep dividing `temp` until zero.
                temp := div(temp, 10)
                // prettier-ignore
                if iszero(temp) { break }
            }

            let length := sub(end, str)
            // Move the pointer 32 bytes leftwards to make room for the length.
            str := sub(str, 0x20)
            // Store the length.
            mstore(str, length)
        }
    }
}

// File: erc721a/contracts/extensions/ERC721AQueryable.sol



// SPDX-License-Identifier: MIT
// ERC721A Contracts v4.2.3
// Creator: Chiru Labs

pragma solidity ^0.8.4;

import './IERC721AQueryable.sol';
import '../ERC721A.sol';

/**
 * @title ERC721AQueryable.
 *
 * @dev ERC721A subclass with convenience query functions.
 */
abstract contract ERC721AQueryable is ERC721A, IERC721AQueryable {
    /**
     * @dev Returns the `TokenOwnership` struct at `tokenId` without reverting.
     *
     * If the `tokenId` is out of bounds:
     *
     * - `addr = address(0)`
     * - `startTimestamp = 0`
     * - `burned = false`
     * - `extraData = 0`
     *
     * If the `tokenId` is burned:
     *
     * - `addr = <Address of owner before token was burned>`
     * - `startTimestamp = <Timestamp when token was burned>`
     * - `burned = true`
     * - `extraData = <Extra data when token was burned>`
     *
     * Otherwise:
     *
     * - `addr = <Address of owner>`
     * - `startTimestamp = <Timestamp of start of ownership>`
     * - `burned = false`
     * - `extraData = <Extra data at start of ownership>`
     */
    function explicitOwnershipOf(uint256 tokenId) public view virtual override returns (TokenOwnership memory) {
        TokenOwnership memory ownership;
        if (tokenId < _startTokenId() || tokenId >= _nextTokenId()) {
            return ownership;
        }
        ownership = _ownershipAt(tokenId);
        if (ownership.burned) {
            return ownership;
        }
        return _ownershipOf(tokenId);
    }

    /**
     * @dev Returns an array of `TokenOwnership` structs at `tokenIds` in order.
     * See {ERC721AQueryable-explicitOwnershipOf}
     */
    function explicitOwnershipsOf(uint256[] calldata tokenIds)
        external
        view
        virtual
        override
        returns (TokenOwnership[] memory)
    {
        unchecked {
            uint256 tokenIdsLength = tokenIds.length;
            TokenOwnership[] memory ownerships = new TokenOwnership[](tokenIdsLength);
            for (uint256 i; i != tokenIdsLength; ++i) {
                ownerships[i] = explicitOwnershipOf(tokenIds[i]);
            }
            return ownerships;
        }
    }

    /**
     * @dev Returns an array of token IDs owned by `owner`,
     * in the range [`start`, `stop`)
     * (i.e. `start <= tokenId < stop`).
     *
     * This function allows for tokens to be queried if the collection
     * grows too big for a single call of {ERC721AQueryable-tokensOfOwner}.
     *
     * Requirements:
     *
     * - `start < stop`
     */
    function tokensOfOwnerIn(
        address owner,
        uint256 start,
        uint256 stop
    ) external view virtual override returns (uint256[] memory) {
        unchecked {
            if (start >= stop) revert InvalidQueryRange();
            uint256 tokenIdsIdx;
            uint256 stopLimit = _nextTokenId();
            // Set `start = max(start, _startTokenId())`.
            if (start < _startTokenId()) {
                start = _startTokenId();
            }
            // Set `stop = min(stop, stopLimit)`.
            if (stop > stopLimit) {
                stop = stopLimit;
            }
            uint256 tokenIdsMaxLength = balanceOf(owner);
            // Set `tokenIdsMaxLength = min(balanceOf(owner), stop - start)`,
            // to cater for cases where `balanceOf(owner)` is too big.
            if (start < stop) {
                uint256 rangeLength = stop - start;
                if (rangeLength < tokenIdsMaxLength) {
                    tokenIdsMaxLength = rangeLength;
                }
            } else {
                tokenIdsMaxLength = 0;
            }
            uint256[] memory tokenIds = new uint256[](tokenIdsMaxLength);
            if (tokenIdsMaxLength == 0) {
                return tokenIds;
            }
            // We need to call `explicitOwnershipOf(start)`,
            // because the slot at `start` may not be initialized.
            TokenOwnership memory ownership = explicitOwnershipOf(start);
            address currOwnershipAddr;
            // If the starting slot exists (i.e. not burned), initialize `currOwnershipAddr`.
            // `ownership.address` will not be zero, as `start` is clamped to the valid token ID range.
            if (!ownership.burned) {
                currOwnershipAddr = ownership.addr;
            }
            for (uint256 i = start; i != stop && tokenIdsIdx != tokenIdsMaxLength; ++i) {
                ownership = _ownershipAt(i);
                if (ownership.burned) {
                    continue;
                }
                if (ownership.addr != address(0)) {
                    currOwnershipAddr = ownership.addr;
                }
                if (currOwnershipAddr == owner) {
                    tokenIds[tokenIdsIdx++] = i;
                }
            }
            // Downsize the array to fit.
            assembly {
                mstore(tokenIds, tokenIdsIdx)
            }
            return tokenIds;
        }
    }

    /**
     * @dev Returns an array of token IDs owned by `owner`.
     *
     * This function scans the ownership mapping and is O(`totalSupply`) in complexity.
     * It is meant to be called off-chain.
     *
     * See {ERC721AQueryable-tokensOfOwnerIn} for splitting the scan into
     * multiple smaller scans if the collection is large enough to cause
     * an out-of-gas error (10K collections should be fine).
     */
    function tokensOfOwner(address owner) external view virtual override returns (uint256[] memory) {
        unchecked {
            uint256 tokenIdsIdx;
            address currOwnershipAddr;
            uint256 tokenIdsLength = balanceOf(owner);
            uint256[] memory tokenIds = new uint256[](tokenIdsLength);
            TokenOwnership memory ownership;
            for (uint256 i = _startTokenId(); tokenIdsIdx != tokenIdsLength; ++i) {
                ownership = _ownershipAt(i);
                if (ownership.burned) {
                    continue;
                }
                if (ownership.addr != address(0)) {
                    currOwnershipAddr = ownership.addr;
                }
                if (currOwnershipAddr == owner) {
                    tokenIds[tokenIdsIdx++] = i;
                }
            }
            return tokenIds;
        }
    }
}

// File: erc721a/contracts/extensions/IERC721AQueryable.sol



// SPDX-License-Identifier: MIT
// ERC721A Contracts v4.2.3
// Creator: Chiru Labs

pragma solidity ^0.8.4;

import '../IERC721A.sol';

/**
 * @dev Interface of ERC721AQueryable.
 */
interface IERC721AQueryable is IERC721A {
    /**
     * Invalid query range (`start` >= `stop`).
     */
    error InvalidQueryRange();

    /**
     * @dev Returns the `TokenOwnership` struct at `tokenId` without reverting.
     *
     * If the `tokenId` is out of bounds:
     *
     * - `addr = address(0)`
     * - `startTimestamp = 0`
     * - `burned = false`
     * - `extraData = 0`
     *
     * If the `tokenId` is burned:
     *
     * - `addr = <Address of owner before token was burned>`
     * - `startTimestamp = <Timestamp when token was burned>`
     * - `burned = true`
     * - `extraData = <Extra data when token was burned>`
     *
     * Otherwise:
     *
     * - `addr = <Address of owner>`
     * - `startTimestamp = <Timestamp of start of ownership>`
     * - `burned = false`
     * - `extraData = <Extra data at start of ownership>`
     */
    function explicitOwnershipOf(uint256 tokenId) external view returns (TokenOwnership memory);

    /**
     * @dev Returns an array of `TokenOwnership` structs at `tokenIds` in order.
     * See {ERC721AQueryable-explicitOwnershipOf}
     */
    function explicitOwnershipsOf(uint256[] memory tokenIds) external view returns (TokenOwnership[] memory);

    /**
     * @dev Returns an array of token IDs owned by `owner`,
     * in the range [`start`, `stop`)
     * (i.e. `start <= tokenId < stop`).
     *
     * This function allows for tokens to be queried if the collection
     * grows too big for a single call of {ERC721AQueryable-tokensOfOwner}.
     *
     * Requirements:
     *
     * - `start < stop`
     */
    function tokensOfOwnerIn(
        address owner,
        uint256 start,
        uint256 stop
    ) external view returns (uint256[] memory);

    /**
     * @dev Returns an array of token IDs owned by `owner`.
     *
     * This function scans the ownership mapping and is O(`totalSupply`) in complexity.
     * It is meant to be called off-chain.
     *
     * See {ERC721AQueryable-tokensOfOwnerIn} for splitting the scan into
     * multiple smaller scans if the collection is large enough to cause
     * an out-of-gas error (10K collections should be fine).
     */
    function tokensOfOwner(address owner) external view returns (uint256[] memory);
}

// File: erc721a/contracts/IERC721A.sol



// SPDX-License-Identifier: MIT
// ERC721A Contracts v4.2.3
// Creator: Chiru Labs

pragma solidity ^0.8.4;

/**
 * @dev Interface of ERC721A.
 */
interface IERC721A {
    /**
     * The caller must own the token or be an approved operator.
     */
    error ApprovalCallerNotOwnerNorApproved();

    /**
     * The token does not exist.
     */
    error ApprovalQueryForNonexistentToken();

    /**
     * Cannot query the balance for the zero address.
     */
    error BalanceQueryForZeroAddress();

    /**
     * Cannot mint to the zero address.
     */
    error MintToZeroAddress();

    /**
     * The quantity of tokens minted must be more than zero.
     */
    error MintZeroQuantity();

    /**
     * The token does not exist.
     */
    error OwnerQueryForNonexistentToken();

    /**
     * The caller must own the token or be an approved operator.
     */
    error TransferCallerNotOwnerNorApproved();

    /**
     * The token must be owned by `from`.
     */
    error TransferFromIncorrectOwner();

    /**
     * Cannot safely transfer to a contract that does not implement the
     * ERC721Receiver interface.
     */
    error TransferToNonERC721ReceiverImplementer();

    /**
     * Cannot transfer to the zero address.
     */
    error TransferToZeroAddress();

    /**
     * The token does not exist.
     */
    error URIQueryForNonexistentToken();

    /**
     * The `quantity` minted with ERC2309 exceeds the safety limit.
     */
    error MintERC2309QuantityExceedsLimit();

    /**
     * The `extraData` cannot be set on an unintialized ownership slot.
     */
    error OwnershipNotInitializedForExtraData();

    // =============================================================
    //                            STRUCTS
    // =============================================================

    struct TokenOwnership {
        // The address of the owner.
        address addr;
        // Stores the start time of ownership with minimal overhead for tokenomics.
        uint64 startTimestamp;
        // Whether the token has been burned.
        bool burned;
        // Arbitrary data similar to `startTimestamp` that can be set via {_extraData}.
        uint24 extraData;
    }

    // =============================================================
    //                         TOKEN COUNTERS
    // =============================================================

    /**
     * @dev Returns the total number of tokens in existence.
     * Burned tokens will reduce the count.
     * To get the total number of tokens minted, please see {_totalMinted}.
     */
    function totalSupply() external view returns (uint256);

    // =============================================================
    //                            IERC165
    // =============================================================

    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * [EIP section](https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified)
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);

    // =============================================================
    //                            IERC721
    // =============================================================

    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

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

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

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

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

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

    /**
     * @dev Equivalent to `safeTransferFrom(from, to, tokenId, '')`.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external payable;

    /**
     * @dev Transfers `tokenId` 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 payable;

    /**
     * @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 payable;

    /**
     * @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);

    // =============================================================
    //                        IERC721Metadata
    // =============================================================

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

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

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

    // =============================================================
    //                           IERC2309
    // =============================================================

    /**
     * @dev Emitted when tokens in `fromTokenId` to `toTokenId`
     * (inclusive) is transferred from `from` to `to`, as defined in the
     * [ERC2309](https://eips.ethereum.org/EIPS/eip-2309) standard.
     *
     * See {_mintERC2309} for more details.
     */
    event ConsecutiveTransfer(uint256 indexed fromTokenId, uint256 toTokenId, address indexed from, address indexed to);
}