// SPDX-License-Identifier: MIXED

// Sources flattened with hardhat v2.9.3 https://hardhat.org

// File @openzeppelin/contracts/utils/Context.sol@v4.3.2

// License-Identifier: MIT

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/access/Ownable.sol@v4.3.2

// License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

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

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

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

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

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}


// File @openzeppelin/contracts/utils/introspection/IERC165.sol@v4.3.2

// License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}


// File @openzeppelin/contracts/utils/introspection/ERC165.sol@v4.3.2

// License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @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 contracts/interfaces/INFTExtension.sol

// License-Identifier: MIT
pragma solidity ^0.8.9;

interface INFTExtension is IERC165 {
}

interface INFTURIExtension is INFTExtension {
    function tokenURI(uint256 tokenId) external view returns (string memory);
}


// File @openzeppelin/contracts/token/ERC721/IERC721.sol@v4.3.2

// License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

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

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

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

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

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

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

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

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;
}


// File contracts/interfaces/IMetaverseNFT.sol

// License-Identifier: MIT
pragma solidity ^0.8.9;

interface IAvatarNFT {
    function DEVELOPER() external pure returns (string memory _url);

    function DEVELOPER_ADDRESS() external pure returns (address payable _dev);

    // ------ View functions ------
    function saleStarted() external view returns (bool);

    function isExtensionAdded(address extension) external view returns (bool);

    /**
        Extra information stored for each tokenId. Optional, provided on mint
     */
    function data(uint256 tokenId) external view returns (bytes32);

    // ------ Mint functions ------
    /**
        Mint from NFTExtension contract. Optionally provide data parameter.
     */
    function mintExternal(
        uint256 tokenId,
        address to,
        bytes32 data
    ) external payable;

    // ------ Admin functions ------
    function addExtension(address extension) external;

    function revokeExtension(address extension) external;

    function withdraw() external;
}

interface IMetaverseNFT is IAvatarNFT {
    // ------ View functions ------
    /**
        Recommended royalty for tokenId sale.
     */
    function royaltyInfo(uint256 tokenId, uint256 salePrice)
        external
        view
        returns (address receiver, uint256 royaltyAmount);

    // ------ Admin functions ------
    function setRoyaltyReceiver(address receiver) external;

    function setRoyaltyFee(uint256 fee) external;
}


// File contracts/extensions/base/NFTExtension.sol

// License-Identifier: MIT
pragma solidity ^0.8.9;


contract NFTExtension is INFTExtension, ERC165 {
    IMetaverseNFT public immutable nft;

    constructor(address _nft) {
        nft = IMetaverseNFT(_nft);
    }

    function beforeMint() internal view {
        require(nft.isExtensionAdded(address(this)), "NFTExtension: this contract is not allowed to be used as an extension");
    }

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

}


// File contracts/extensions/base/SaleControl.sol

// License-Identifier: MIT
pragma solidity ^0.8.9;

abstract contract SaleControl is Ownable {

    uint256 public constant __SALE_NEVER_STARTS = 2**256 - 1;

    uint256 public startTimestamp = __SALE_NEVER_STARTS;

    modifier whenSaleStarted {
        require(saleStarted(), "Sale not started yet");
        _;
    }

    function updateStartTimestamp(uint256 _startTimestamp) public onlyOwner {
        startTimestamp = _startTimestamp;
    }

    function startSale() public onlyOwner {
        startTimestamp = block.timestamp;
    }

    function stopSale() public onlyOwner {
        startTimestamp = __SALE_NEVER_STARTS;
    }

    function saleStarted() public view returns (bool) {
        return block.timestamp >= startTimestamp;
    }
}


// File contracts/extensions/LimitAmountSaleExtension.sol

// License-Identifier: MIT
pragma solidity ^0.8.9;


contract LimitAmountSaleExtension is NFTExtension, Ownable, SaleControl {

    uint256 public price;
    uint256 public maxPerMint;
    uint256 public totalMinted;
    uint256 public maxSupply;

    constructor(address _nft, uint256 _price, uint256 _maxPerMint, uint256 _maxSupply) NFTExtension(_nft) {
        stopSale();
        // sale stopped by default

        price = _price;
        maxPerMint = _maxPerMint;
        maxSupply = _maxSupply;
    }

    function mint(uint256 nTokens) external whenSaleStarted payable {
        super.beforeMint();

        require(nTokens + totalMinted <= maxSupply, "max supply reached");
        require(nTokens <= maxPerMint, "Too many tokens to mint");
        require(msg.value >= nTokens * price, "Not enough ETH to mint");

        nft.mintExternal{ value: msg.value }(nTokens, msg.sender, bytes32(0x0));

        totalMinted += nTokens;
    }

}