// File: contracts/Synesthesia.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.9;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "./ColorPalette.sol";
import "./colors/Color.sol";
import "./colors/IColorProvider.sol";
import "./IMetadataRenderer.sol";
import "./tokens/ERC721Slim.sol";
import "./utils/Base64.sol";
import "./utils/Random.sol";

contract Synesthesia is ERC721Slim, ColorPalette, Ownable {
    uint256 public constant MAX_MINT_PER_TX = 20;
    uint256 public constant UNIT_PRICE = 0.055 ether;

    uint8 private constant SALE_STATE_NOT_STARTED = 0;
    uint8 private constant SALE_STATE_STARTED = 1;
    uint8 private constant SALE_STATE_CLOSED = 2;

    address public constant OPENDAO_TREASURY = 0xd08d0e994EeEf4001C63C72991Cf05918aDF191b;

    struct Config {
        uint8 saleState;
        uint16 maxSupply;
        uint128 randomSeed;
        uint104 minterSeed;
    }

    bytes32 public immutable _saltHash;
    Config public _config;
    IMetadataRenderer _renderer;

    constructor(uint16 maxSupply, bytes32 saltHash, address renderer, IColorProvider[] memory colorProviders)
        ERC721Slim("Synesthesia", "SYNES")
    {
        require(renderer != address(0), "Synesthesia: renderer shouldn't be zero address");
        require(maxSupply > 0, "Synesthesia: max supply should be larger than zero");
        require(saltHash != 0, "Synesthesia: salt hash cannot be zero");

        _setColorProviders(colorProviders);

        _config = Config({
            saleState: SALE_STATE_NOT_STARTED,
            maxSupply: maxSupply,
            randomSeed: 0,
            minterSeed: 0
        });

        _renderer = IMetadataRenderer(renderer);
        _saltHash = saltHash;
    }

    function sqeezePigmentTube(uint256 amount) external payable {
        Config memory config = _config;

        require(tx.origin == msg.sender, "Synesthesia: are you botting?");
        require(config.saleState == SALE_STATE_STARTED, "Synesthesia: sale is not yet started");
        require(amount <= MAX_MINT_PER_TX, "Synesthesia: exceeds maximum amount per transaction");
        require(amount * UNIT_PRICE <= msg.value, "Synesthesia: insufficient fund");
        require(amount + totalMinted() <= config.maxSupply, "Synesthesia: exceeds total supply");

        _safeBatchMint(msg.sender, amount);

        config.minterSeed = uint104(uint256(keccak256(abi.encodePacked(config.minterSeed, msg.sender))));
        _config = config;
    }

    function setRenderer(address renderer) external onlyOwner {
        _renderer = IMetadataRenderer(renderer);
    }

    function setColorProvier(IColorProvider[] memory colorProviders) external onlyOwner {
        _setColorProviders(colorProviders);
    }

    function setSaleState(uint8 targetSaleState) external onlyOwner {
        _config.saleState = targetSaleState;
    }

    function revealColors(string memory salt) external onlyOwner {
        require(keccak256(bytes(salt)) == _saltHash, "Synesthesia: invalid salt");
        require(_config.randomSeed == 0, "Synesthesia: already revealed");

        uint256 lastBlock = block.number - 1;
        _config.randomSeed = uint128(uint256(keccak256(abi.encodePacked(
            salt,
            _config.minterSeed,
            uint256(blockhash(lastBlock)),
            uint256(block.timestamp)))));
    }

    function withdraw() external onlyOwner {
        uint256 balance = address(this).balance;
        uint256 feedbackToOpenDAO = balance * 10 / 100;

        Address.sendValue(payable(OPENDAO_TREASURY), feedbackToOpenDAO);
        Address.sendValue(payable(msg.sender), balance - feedbackToOpenDAO);
    }

    function functionCall(address target, bytes calldata data) external payable onlyOwner {
        Address.functionCallWithValue(target, data, msg.value);
    }

    // ========================================
    //    IERC721Metadata implementations
    // ========================================

    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), "Synesthesia: URI query for nonexistent token");
        Config memory config = _config;

        if (_config.randomSeed == 0) {
            return _renderer.renderUnreveal(uint16(tokenId));
        } else {
            uint16 randomizedId = Random.getRandomizedId(
                uint16(tokenId),
                uint16(config.maxSupply),
                config.randomSeed);
            Color memory color = getColor(randomizedId);

            return _renderer.render(uint16(tokenId), color);
        }
    }
}

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



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

pragma solidity ^0.8.0;

import "../utils/Context.sol";

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

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

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

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

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

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

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



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

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

// File: contracts/ColorPalette.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.9;

import "./colors/Color.sol";
import "./colors/IColorProvider.sol";
import "./utils/Base64.sol";

abstract contract ColorPalette {
    struct ColorDependency {
        IColorProvider provider;
        uint96 accumulateAmount;
    }

    ColorDependency[] public _colorProviders;

    function _setColorProviders(IColorProvider[] memory colorProviders) internal {
        delete _colorProviders;

        uint96 accAmount = 0;
        for (uint i = 0; i < colorProviders.length; i++) {
            IColorProvider p = colorProviders[i];

            accAmount += uint96(p.totalAmount());
            _colorProviders.push(ColorDependency(p, accAmount));
        }
    }

    function getColor(uint16 id) public view returns (Color memory) {
        uint256 providerCount = _colorProviders.length;
        uint96 lastAccAmount = 0;

        for (uint i = 0; i < providerCount; i++) {
            ColorDependency memory dep = _colorProviders[i];

            if (id < dep.accumulateAmount) return dep.provider.getColor(id - lastAccAmount);
            lastAccAmount = dep.accumulateAmount;
        }

        revert("ColorPalette: id of color cannot exceed 16,000");
    }
}
// File: contracts/colors/Color.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.9;

struct Color {
    string rgb;
    string name;
}

// File: contracts/colors/IColorProvider.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.9;

import "./Color.sol";

abstract contract IColorProvider {
    function totalAmount() public pure virtual returns (uint96);
    function getColor(uint128 id) public pure virtual returns (Color memory);

    bytes16 private constant HEX_ALPHABET = "0123456789ABCDEF";

    function _getColor(
        bytes memory names,
        bytes memory rgbs,
        uint128 index
    ) internal pure returns (Color memory) {
        return Color({
            rgb: string(getColorRgb(rgbs, index)), 
            name: string(getColorName(names, index))
        });
    }

    function getColorName(bytes memory names, uint128 index) internal pure returns (bytes memory) {
        bytes memory result;
        uint256 startIndex = 0;
        uint256 endIndex = 0;

        // Find start index
        for (; startIndex < names.length && index > 0; startIndex++) {
            if (names[startIndex] != "|") continue;

            index--;
        }

        // Find end index. Either next delimeter or terminator.
        for (endIndex = startIndex + 1; endIndex < names.length && names[endIndex] != "|"; endIndex++) {}

        for (; startIndex < endIndex; startIndex++) {
            result = abi.encodePacked(result, names[startIndex]);
        }

        return result;
    }

    function getColorRgb(bytes memory rgbs, uint128 index) internal pure returns (bytes memory) {
        uint256 startIndex = 3 * uint256(index);

        return abi.encodePacked(
            HEX_ALPHABET[(uint8(rgbs[startIndex + 0]) >> 4) & 0xF],
            HEX_ALPHABET[uint8(rgbs[startIndex + 0]) & 0xF],
            HEX_ALPHABET[(uint8(rgbs[startIndex + 1]) >> 4) & 0xF],
            HEX_ALPHABET[uint8(rgbs[startIndex + 1]) & 0xF],
            HEX_ALPHABET[(uint8(rgbs[startIndex + 2]) >> 4) & 0xF],
            HEX_ALPHABET[uint8(rgbs[startIndex + 2]) & 0xF]);
    }
}

// File: contracts/IMetadataRenderer.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.9;

import "./colors/Color.sol";

interface IMetadataRenderer {
    function renderUnreveal(uint16 tokenId) external view returns (string memory);
    function render(uint16 tokenId, Color memory color) external view returns (string memory);
}

// File: contracts/tokens/ERC721Slim.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.9;

import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "@openzeppelin/contracts/utils/Context.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/utils/introspection/ERC165.sol";

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension and the Enumerable extensions.
 *
 * This implementation is called `Slim` because the gas usage is extremely saved in the minting, transfer operations.
 * But as a drawback, those view functions like balanceOf and any functions from IERC721Enumerable
 * will be costly because it needs heavy iterations over the array that stores the token array.
 */
contract ERC721Slim is Context, ERC165, IERC721, IERC721Metadata, IERC721Enumerable {
    using Address for address;
    using Strings for uint256;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    uint256 private _burntTokens = 0;
    address[] private _tokenOwners;
    mapping(uint256 => address) _tokenApprovals;

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

    /**
     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            interfaceId == type(IERC721Enumerable).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721Slim: balance query for the zero address");

        uint256 balance = 0;
        for (uint i = 0; i < _tokenOwners.length; i++) {
            if (_tokenOwners[i] == owner) {
                balance++;
            }
        }

        return balance;
    }

    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        require(_exists(tokenId), "ERC721Slim: owner query for nonexistent token");
        address owner = _tokenOwners[tokenId];
        require(owner != address(0), "ERC721Slim: owner query for nonexistent token");
        return owner;
    }

    /**
     * @dev See {IERC721Metadata-name}.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev See {IERC721Metadata-symbol}.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
        return "";
    }

    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ERC721Slim.ownerOf(tokenId);
        require(to != owner, "ERC721Slim: approval to current owner");

        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            "ERC721Slim: approve caller is not owner nor approved for all"
        );

        _approve(to, tokenId);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        require(_exists(tokenId), "ERC721Slim: approved query for nonexistent token");

        return _tokenApprovals[tokenId];
    }

    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        _setApprovalForAll(_msgSender(), operator, approved);
    }

    /**
     * @dev See {IERC721-isApprovedForAll}.
     */
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721Slim: transfer caller is not owner nor approved");

        _transfer(from, to, tokenId);
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        safeTransferFrom(from, to, tokenId, "");
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721Slim: transfer caller is not owner nor approved");
        _safeTransfer(from, to, tokenId, _data);
    }

    /**
     * @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.
     *
     * `_data` is additional data, it has no specified format and it is sent in call to `to`.
     *
     * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
     * implement alternative mechanisms to perform token transfer, such as signature-based.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeTransfer(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) internal virtual {
        _transfer(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721Slim: transfer to non ERC721Receiver implementer");
    }

    /**
     * @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 (`_mint`),
     * and stop existing when they are burned (`_burn`).
     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return tokenId < _tokenOwners.length && _tokenOwners[tokenId] != address(0);
    }

    /**
     * @dev Returns whether `spender` is allowed to manage `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        require(_exists(tokenId), "ERC721Slim: operator query for nonexistent token");
        address owner = ERC721Slim.ownerOf(tokenId);
        return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
    }

    /**
     * @dev Safely mints `tokenId` in batch and transfers it to `to`.
     *
     * Requirements:
     *
     * - `to` must not be a zero address.
     * - `amount` must not be zero
     */
    function _safeBatchMint(address to, uint256 amount) internal returns (uint256 startId) {
        require(to != address(0), "ERC721Slim: mint to the zero address");
        require(amount > 0, "ERC721Slim: mint nothing");
        startId = _tokenOwners.length;

        for (uint256 i = 0; i < amount; i++) {
            _tokenOwners.push(to);

            emit Transfer(address(0), to, _tokenOwners.length - 1);
        }

        require(
            _checkOnERC721Received(address(0), to, startId, ""),
            "ERC721Slim: transfer to non ERC721Receiver implementer"
        );
    }

    /**
     * @dev Safely mints `tokenId` and transfers it to `to`.
     *
     * Requirements:
     *
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeMint(address to) internal virtual {
        _safeMint(to, "");
    }

    /**
     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
     */
    function _safeMint(
        address to,
        bytes memory _data
    ) internal virtual {
        uint256 tokenId = _mint(to);
        require(
            _checkOnERC721Received(address(0), to, tokenId, _data),
            "ERC721Slim: transfer to non ERC721Receiver implementer"
        );
    }

    /**
     * @dev Mints `tokenId` and transfers it to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     *
     * Emits a {Transfer} event.
     */
    function _mint(address to) internal virtual returns (uint256) {
        require(to != address(0), "ERC721Slim: mint to the zero address");

        uint256 tokenId = _tokenOwners.length;
        _tokenOwners.push(to);

        emit Transfer(address(0), to, tokenId);

        return tokenId;
    }

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721Slim.ownerOf(tokenId);

        _tokenOwners[tokenId] = address(0);
        delete _tokenApprovals[tokenId];
        _burntTokens++;

        emit Approval(owner, address(0), tokenId);
        emit Transfer(owner, address(0), tokenId);
    }

    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     *
     * Emits a {Transfer} event.
     */
    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {
        require(ERC721Slim.ownerOf(tokenId) == from, "ERC721Slim: transfer from incorrect owner");
        require(to != address(0), "ERC721Slim: transfer to the zero address");

        _tokenOwners[tokenId] = to;
        _tokenApprovals[tokenId] = address(0);

        emit Approval(from, address(0), tokenId);
        emit Transfer(from, to, tokenId);
    }

    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * Emits a {Approval} event.
     */
    function _approve(address to, uint256 tokenId) internal virtual {
        _tokenApprovals[tokenId] = to;
        emit Approval(_tokenOwners[tokenId], to, tokenId);
    }

    /**
     * @dev Approve `operator` to operate on all of `owner` tokens
     *
     * Emits a {ApprovalForAll} event.
     */
    function _setApprovalForAll(
        address owner,
        address operator,
        bool approved
    ) internal virtual {
        require(owner != operator, "ERC721Slim: approve to caller");
        _operatorApprovals[owner][operator] = approved;
        emit ApprovalForAll(owner, operator, approved);
    }

    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
     * The call is not executed if the target address is not a contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param _data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    function _checkOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) private returns (bool) {
        if (to.isContract()) {
            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
                return retval == IERC721Receiver.onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert("ERC721Slim: transfer to non ERC721Receiver implementer");
                } else {
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }

    // ========================================
    //    IERC721Enumerable implementations
    // ========================================

    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() public override view returns (uint256) {
        return _tokenOwners.length - _burntTokens;
    }

    /**
     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId) {
        uint256 _totalSupply = _tokenOwners.length;

        for (uint i = 0; i < _totalSupply; i++) {
            if (_tokenOwners[i] != owner) continue;

            if (index == 0) {
                return i;
            }

            index--;
        }

        revert("ERC721Slim: owner index out of bounds");
    }

    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256) {
        require(index < _tokenOwners.length, "ERC721Slim: global index out of bounds");
        
        // Adjusted token orders by skipping burnt tokens
        uint256 burntTokens = 0;
        for (uint256 i = 0; i < _tokenOwners.length; i++) {
            if (_tokenOwners[i] == address(0)) {
                burntTokens++;
            }

            if (i == index + burntTokens) return i;
        }
        
        revert("ERC721Slim: global index out of bounds");
    }

    // ========================================
    //    Miscellaneous functions
    // ========================================

    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalMinted() public view returns (uint256) {
        return _tokenOwners.length;
    }
}

// File: contracts/utils/Base64.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.9;

library Base64 {
    string constant private B64_ALPHABET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';

    function encode(bytes memory _data) internal pure returns (string memory result) {
        if (_data.length == 0) return '';
        string memory _table = B64_ALPHABET;
        uint256 _encodedLen = 4 * ((_data.length + 2) / 3);
        result = new string(_encodedLen + 32);

        assembly {
            mstore(result, _encodedLen)
            let tablePtr := add(_table, 1)
            let dataPtr := _data
            let endPtr := add(dataPtr, mload(_data))
            let resultPtr := add(result, 32)

            for {} lt(dataPtr, endPtr) {}
            {
                dataPtr := add(dataPtr, 3)
                let input := mload(dataPtr)
                mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr(18, input), 0x3F)))))
                resultPtr := add(resultPtr, 1)
                mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr(12, input), 0x3F)))))
                resultPtr := add(resultPtr, 1)
                mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr(6, input), 0x3F)))))
                resultPtr := add(resultPtr, 1)
                mstore(resultPtr, shl(248, mload(add(tablePtr, and(input, 0x3F)))))
                resultPtr := add(resultPtr, 1)
            }
            
            switch mod(mload(_data), 3)
            case 1 {mstore(sub(resultPtr, 2), shl(240, 0x3d3d))}
            case 2 {mstore(sub(resultPtr, 1), shl(248, 0x3d))}
        }

        return result;
    }
}
// File: contracts/utils/Random.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.9;

/**
 * @dev A pesudo-random number generator that built based on LCG algorithm.
 */
library Random {
    uint256 private constant A = 48271;
    uint256 private constant M = type(uint32).max;
    uint256 private constant C = 0;

    /**
     * @dev Map a number between [0, `idMax`) to another number in the range of [0, `idMax`) randomly
     * with a determined `randomSeed`
     */
    function getRandomizedId(
        uint16 id,
        uint16 idMax,
        uint256 randomSeed
    ) internal pure returns (uint16) {
        uint16[] memory newIdSeq = new uint16[](idMax);
        uint256 seed = randomSeed;

        for (uint16 i = 0; i < idMax; i++) newIdSeq[i] = i;

        for (uint16 i = 0; i < idMax; i++) {
            // LCG
            unchecked { seed = (A * seed + C) % M; }

            uint16 iToSwap = uint16(seed % idMax);
            uint16 temp = newIdSeq[i];
            newIdSeq[i] = newIdSeq[iToSwap];
            newIdSeq[iToSwap] = temp;
        }

        return newIdSeq[id];
    }
}

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



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

pragma solidity ^0.8.0;

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

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

// File: @openzeppelin/contracts/token/ERC721/IERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

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

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

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

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

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

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Enumerable.sol)

pragma solidity ^0.8.0;

import "../IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {
    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId);

    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256);
}

// File: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {
    /**
     * @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);
}

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



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

pragma solidity ^0.8.0;

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

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

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

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

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

// File: @openzeppelin/contracts/utils/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);
}