// File: /contracts/SkateContract.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.6;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import {ReentrancyGuardUpgradeable} from "@openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol";
import {IGnarSeeder} from "./GNARSeeder.sol";
import {IGnarDescriptor} from "./GNARDescriptor.sol";

/**
 * @title SkateContract
 */
contract SkateContract is
    ERC721Enumerable,
    Ownable,
    ReentrancyGuardUpgradeable
{
    using Strings for uint256;

    struct Auction {
        // ID for the gnar (ERC721 token ID)
        uint256 gnarId;
        // The current highest bid amount
        uint256 amount;
        // The block number that the auction started
        uint256 startBlock;
        // The time that the auction is scheduled to end
        uint256 endBlock;
        // The address of the current highest bid
        address payable bidder;
        // Skate percentage
        uint8 skatePercent;
        // Dao percentage
        uint8 daoPercent;
        // Whether or not the auction has been settled
        bool settled;
    }

    event AuctionCreated(uint256 indexed gnarId);
    event AuctionBid(
        uint256 indexed gnarId,
        address sender,
        uint256 value,
        uint256 timestamp
    );
    event AuctionSettled(
        uint256 indexed gnarId,
        address winner,
        uint256 amount,
        uint256 timestamp
    );
    event MinBidIncrementPercentageUpdated(uint8 percent);
    event ReservePriceUpdated(uint256 price);

    // The number of blocks an auction lasts
    uint16 public auctionPeriodBlocks = 666;
    // The Gnar token URI descriptor address
    IGnarDescriptor public descriptor;
    // The Gnar token seeder
    IGnarSeeder public seeder;
    // The internal Skate ID tracker
    uint256 public currentGnarId;
    // current Auction info like gnarId,
    Auction public auction;
    // The minimum price accepted in an auction
    uint256 public reservePrice;
    // The minimum percentage difference between the last bid amount and the current bid
    uint8 public minBidIncrementPercentage;
    // The seeds
    mapping(uint256 => IGnarSeeder.Seed) public seeds;
    // paused
    bool public paused = true;
    // skate address
    address public skate;
    // dao address
    address public dao;

    constructor(
        address _skate,
        address _dao,
        address _descriptor,
        address _seeder,
        uint256 _reservePrice,
        uint8 _minBidIncrementPercentage
    ) ERC721("Skate or DAO", "GNAR") {
        require(
            _skate != address(0) &&
                _dao != address(0) &&
                _descriptor != address(0) &&
                _seeder != address(0),
            "ZERO ADDRESS"
        );
        skate = _skate;
        dao = _dao;
        descriptor = IGnarDescriptor(_descriptor);
        seeder = IGnarSeeder(_seeder);
        reservePrice = _reservePrice;
        minBidIncrementPercentage = _minBidIncrementPercentage;
    }

    /**
     * set skate and dao address
     */
    function setSkateDaoAddresses(address _skate, address _dao)
        external
        onlyOwner
    {
        require(_skate != address(0) && _dao != address(0), "ZERO ADDRESS");
        skate = _skate;
        dao = _dao;
    }

    /**
     * Auction start by onwer
     */
    function auctionStart() external onlyOwner {
        require(paused, "Auction already started");
        paused = false;
        _createAuction();
    }

    /**
     * @notice Settle the current auction, mint a new Gnar, and put it up for auction.
     */
    function settleCurrentAndCreateNewAuction() external nonReentrant {
        require(!paused, "Auction is paused");
        _settleAuction();
        _createAuction();
    }

    /**
     * @notice Set the token URI descriptor.
     * @dev Only callable by the owner when not locked.
     */
    function setDescriptor(address _descriptor) external onlyOwner {
        require(_descriptor != address(0), "ZERO ADDRESS");
        descriptor = IGnarDescriptor(_descriptor);
    }

    /**
     * @notice Set the token seeder.
     * @dev Only callable by the owner when not locked.
     */
    function setSeeder(address _seeder) external onlyOwner {
        require(_seeder != address(0), "ZERO ADDRESS");
        seeder = IGnarSeeder(_seeder);
    }

    function mint() internal returns (uint256) {
        IGnarSeeder.Seed memory _seed = seeder.generateSeed(
            currentGnarId,
            descriptor
        );
        uint256 tokenId = currentGnarId;
        _safeMint(msg.sender, tokenId);
        currentGnarId++;
        seeds[tokenId] = _seed;
        return tokenId;
    }

    function tokenURI(uint256 tokenId)
        public
        view
        virtual
        override
        returns (string memory)
    {
        require(_exists(tokenId), "Nonexistent token");

        return descriptor.tokenURI(tokenId, seeds[tokenId]);
    }

    /**
     * @notice Create a bid for a Gnar, with a given amount.
     * @dev This contract only accepts payment in ETH.
     */
    function createBid(
        uint256 gnarId,
        uint8 _skatePercent,
        uint8 _daoPercent
    ) external payable nonReentrant {
        Auction memory _auction = auction;

        require(_auction.gnarId == gnarId, "Gnar not up for auction");
        require(
            _skatePercent + _daoPercent == 100,
            "Sum of percents is not 100"
        );
        require(block.number < _auction.endBlock, "Auction expired");
        require(msg.value >= reservePrice, "Must send at least reservePrice");
        require(
            msg.value >=
                _auction.amount +
                    ((_auction.amount * minBidIncrementPercentage) / 100),
            "Must send more than last bid by minBidIncrementPercentage amount"
        );

        address payable lastBidder = _auction.bidder;

        // Refund the last bidder, if applicable
        if (lastBidder != address(0)) {
            require(
                _safeTransferETH(lastBidder, _auction.amount),
                "ETH transfer failed"
            );
        }

        auction.amount = msg.value;
        auction.bidder = payable(msg.sender);
        auction.skatePercent = _skatePercent;
        auction.daoPercent = _daoPercent;

        emit AuctionBid(
            _auction.gnarId,
            msg.sender,
            msg.value,
            block.timestamp
        );
    }

    /**
     * @notice Create an auction.
     * @dev Store the auction details in the `auction` state variable and emit an AuctionCreated event.
     * If the mint reverts, the minter was updated without pausing this contract first. To remedy this,
     * catch the revert and pause this contract.
     */
    function _createAuction() internal {
        uint256 gnarId = mint();
        uint256 startBlock = block.number;
        uint256 endBlock = startBlock + auctionPeriodBlocks;

        auction = Auction({
            gnarId: gnarId,
            amount: 0,
            startBlock: startBlock,
            endBlock: endBlock,
            bidder: payable(0),
            skatePercent: 50,
            daoPercent: 50,
            settled: false
        });

        emit AuctionCreated(gnarId);
    }

    /**
     * @notice Settle an auction, finalizing the bid and paying out to the owner.
     * @dev If there are no bids, the Gnar is burned.
     */
    function _settleAuction() internal {
        Auction memory _auction = auction;
        require(_auction.startBlock != 0, "Auction hasn't begun");
        require(!_auction.settled, "Auction has already been settled");
        require(block.number >= _auction.endBlock, "Auction hasn't completed");

        auction.settled = true;

        if (_auction.bidder == address(0)) {
            burn(_auction.gnarId);
        } else {
            transferFrom(owner(), _auction.bidder, _auction.gnarId);
        }

        if (_auction.amount > 0) {
            require(
                _safeTransferETH(
                    skate,
                    (_auction.amount * _auction.skatePercent) / 100
                ),
                "ETH transfer failed"
            );
            require(
                _safeTransferETH(
                    dao,
                    (_auction.amount * _auction.daoPercent) / 100
                ),
                "ETH transfer failed"
            );
        }

        emit AuctionSettled(
            _auction.gnarId,
            _auction.bidder,
            _auction.amount,
            block.timestamp
        );
    }

    /**
     * @notice Pause the gnar auction house.
     * @dev This function can only be called by the owner when the
     * contract is unpaused. While no new auctions can be started when paused,
     * anyone can settle an ongoing auction.
     */
    function pause() external onlyOwner {
        require(!paused, "Already Paused");
        paused = true;
    }

    /**
     * @notice Unpause the Gnars auction house.
     * @dev This function can only be called by the owner when the
     * contract is paused. If required, this function will start a new auction.
     */
    function unpause() external onlyOwner {
        require(paused, "Already Auction running");
        paused = false;
        if (auction.endBlock < block.number) {
            if (auction.settled) {
                _createAuction();
            } else {
                _settleAuction();
                _createAuction();
            }
        }
    }

    /**
     * @notice Set the auction reserve price.
     * @dev Only callable by the owner.
     */
    function setReservePrice(uint256 _reservePrice) external onlyOwner {
        reservePrice = _reservePrice;
        emit ReservePriceUpdated(_reservePrice);
    }

    /**
     * @notice Set the auction minimum bid increment percentage.
     * @dev Only callable by the owner.
     */
    function setMinBidIncrementPercentage(uint8 _minBidIncrementPercentage)
        external
        onlyOwner
    {
        minBidIncrementPercentage = _minBidIncrementPercentage;
        emit MinBidIncrementPercentageUpdated(_minBidIncrementPercentage);
    }

    /**
     * @notice Burn a gnar.
     */
    function burn(uint256 gnarId) public onlyOwner {
        _burn(gnarId);
    }

    /**
     * @notice Transfer ETH.
     */
    function _safeTransferETH(address to, uint256 amount)
        internal
        returns (bool)
    {
        (bool success, ) = to.call{value: amount, gas: 50_000}(new bytes(0));
        return success;
    }

    function remainBlocks() external view returns (uint256) {
        require(auction.endBlock >= block.number, "No remain blocks!");
        return auction.endBlock - block.number;
    }

    function setAuctionPeriodBlocks(uint16 _auctionPeriodBlocks)
        external
        onlyOwner
    {
        auctionPeriodBlocks = _auctionPeriodBlocks;
    }
}

// File: /interfaces/IGNARSeeder.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.6;

import {IGnarDescriptor} from "./IGNARDescriptor.sol";

interface IGnarSeeder {
    struct Seed {
        uint48 background;
        uint48 body;
        uint48 accessory;
        uint48 head;
        uint48 glasses;
    }

    function generateSeed(uint256 nounId, IGnarDescriptor descriptor)
        external
        view
        returns (Seed memory);
}

// File: /interfaces/IGNARDescriptor.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.6;

import {IGnarSeeder} from "./IGNARSeeder.sol";

interface IGnarDescriptor {
    event PartsLocked();

    event DataURIToggled(bool enabled);

    event BaseURIUpdated(string baseURI);

    function arePartsLocked() external returns (bool);

    function isDataURIEnabled() external returns (bool);

    function baseURI() external returns (string memory);

    function palettes(uint8 paletteIndex, uint256 colorIndex)
        external
        view
        returns (string memory);

    function backgrounds(uint256 index) external view returns (string memory);

    function bodies(uint256 index) external view returns (bytes memory);

    function accessories(uint256 index) external view returns (bytes memory);

    function heads(uint256 index) external view returns (bytes memory);

    function glasses(uint256 index) external view returns (bytes memory);

    function backgroundCount() external view returns (uint256);

    function bodyCount() external view returns (uint256);

    function accessoryCount() external view returns (uint256);

    function headCount() external view returns (uint256);

    function glassesCount() external view returns (uint256);

    function addManyColorsToPalette(
        uint8 paletteIndex,
        string[] calldata newColors
    ) external;

    function addManyBackgrounds(string[] calldata backgrounds) external;

    function addManyBodies(bytes[] calldata bodies) external;

    function addManyAccessories(bytes[] calldata accessories) external;

    function addManyHeads(bytes[] calldata heads) external;

    function addManyGlasses(bytes[] calldata glasses) external;

    function addColorToPalette(uint8 paletteIndex, string calldata color)
        external;

    function addBackground(string calldata background) external;

    function addBody(bytes calldata body) external;

    function addAccessory(bytes calldata accessory) external;

    function addHead(bytes calldata head) external;

    function addGlasses(bytes calldata glasses) external;

    function lockParts() external;

    function toggleDataURIEnabled() external;

    function setBaseURI(string calldata baseURI) external;

    function tokenURI(uint256 tokenId, IGnarSeeder.Seed memory seed)
        external
        view
        returns (string memory);

    function dataURI(uint256 tokenId, IGnarSeeder.Seed memory seed)
        external
        view
        returns (string memory);

    function genericDataURI(
        string calldata name,
        string calldata description,
        IGnarSeeder.Seed memory seed
    ) external view returns (string memory);

    function generateSVGImage(IGnarSeeder.Seed memory seed)
        external
        view
        returns (string memory);
}

// File: /contracts/libs/MultiPartRLEToSVG.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.6;

library MultiPartRLEToSVG {
    struct SVGParams {
        bytes[] parts;
        string background;
    }

    struct ContentBounds {
        uint8 top;
        uint8 right;
        uint8 bottom;
        uint8 left;
    }

    struct Rect {
        uint8 length;
        uint8 colorIndex;
    }

    struct DecodedImage {
        uint8 paletteIndex;
        ContentBounds bounds;
        Rect[] rects;
    }

    /**
     * @notice Given RLE image parts and color palettes, merge to generate a single SVG image.
     */
    function generateSVG(SVGParams memory params, mapping(uint8 => string[]) storage palettes)
        internal
        view
        returns (string memory svg)
    {
        // prettier-ignore
        return string(
            abi.encodePacked(
                '<svg width="320" height="320" viewBox="0 0 320 320" xmlns="http://www.w3.org/2000/svg" shape-rendering="crispEdges">',
                '<rect width="100%" height="100%" fill="#', params.background, '" />',
                _generateSVGRects(params, palettes),
                '</svg>'
            )
        );
    }

    /**
     * @notice Given RLE image parts and color palettes, generate SVG rects.
     */
    // prettier-ignore
    function _generateSVGRects(SVGParams memory params, mapping(uint8 => string[]) storage palettes)
        private
        view
        returns (string memory svg)
    {
        string[33] memory lookup = [
            '0', '10', '20', '30', '40', '50', '60', '70', 
            '80', '90', '100', '110', '120', '130', '140', '150', 
            '160', '170', '180', '190', '200', '210', '220', '230', 
            '240', '250', '260', '270', '280', '290', '300', '310',
            '320' 
        ];
        string memory rects;
        for (uint8 p = 0; p < params.parts.length; p++) {
            DecodedImage memory image = _decodeRLEImage(params.parts[p]);
            string[] storage palette = palettes[image.paletteIndex];
            uint256 currentX = image.bounds.left;
            uint256 currentY = image.bounds.top;
            uint256 cursor;
            string[16] memory buffer;

            string memory part;
            for (uint256 i = 0; i < image.rects.length; i++) {
                Rect memory rect = image.rects[i];
                if (rect.colorIndex != 0) {
                    buffer[cursor] = lookup[rect.length];          // width
                    buffer[cursor + 1] = lookup[currentX];         // x
                    buffer[cursor + 2] = lookup[currentY];         // y
                    buffer[cursor + 3] = palette[rect.colorIndex]; // color

                    cursor += 4;

                    if (cursor >= 16) {
                        part = string(abi.encodePacked(part, _getChunk(cursor, buffer)));
                        cursor = 0;
                    }
                }

                currentX += rect.length;
                if (currentX == image.bounds.right) {
                    currentX = image.bounds.left;
                    currentY++;
                }
            }

            if (cursor != 0) {
                part = string(abi.encodePacked(part, _getChunk(cursor, buffer)));
            }
            rects = string(abi.encodePacked(rects, part));
        }
        return rects;
    }

    /**
     * @notice Return a string that consists of all rects in the provided `buffer`.
     */
    // prettier-ignore
    function _getChunk(uint256 cursor, string[16] memory buffer) private pure returns (string memory) {
        string memory chunk;
        for (uint256 i = 0; i < cursor; i += 4) {
            chunk = string(
                abi.encodePacked(
                    chunk,
                    '<rect width="', buffer[i], '" height="10" x="', buffer[i + 1], '" y="', buffer[i + 2], '" fill="#', buffer[i + 3], '" />'
                )
            );
        }
        return chunk;
    }

    /**
     * @notice Decode a single RLE compressed image into a `DecodedImage`.
     */
    function _decodeRLEImage(bytes memory image) private pure returns (DecodedImage memory) {
        uint8 paletteIndex = uint8(image[0]);
        ContentBounds memory bounds = ContentBounds({
            top: uint8(image[1]),
            right: uint8(image[2]),
            bottom: uint8(image[3]),
            left: uint8(image[4])
        });

        uint256 cursor;
        Rect[] memory rects = new Rect[]((image.length - 5) / 2);
        for (uint256 i = 5; i < image.length; i += 2) {
            rects[cursor] = Rect({ length: uint8(image[i]), colorIndex: uint8(image[i + 1]) });
            cursor++;
        }
        return DecodedImage({ paletteIndex: paletteIndex, bounds: bounds, rects: rects });
    }
}

// File: /contracts/GNARSeeder.sol



// SPDX-License-Identifier: GPL-3.0

pragma solidity ^0.8.6;

import {IGnarSeeder} from "../interfaces/IGNARSeeder.sol";
import {IGnarDescriptor} from "../interfaces/IGNARDescriptor.sol";

contract GNARSeeder is IGnarSeeder {
    function generateSeed(uint256 gnarId, IGnarDescriptor descriptor)
        external
        view
        override
        returns (Seed memory)
    {
        uint256 pseudorandomness = uint256(
            keccak256(abi.encodePacked(blockhash(block.number - 1), gnarId))
        );

        uint256 backgroundCount = descriptor.backgroundCount();
        uint256 bodyCount = descriptor.bodyCount();
        uint256 accessoryCount = descriptor.accessoryCount();
        uint256 headCount = descriptor.headCount();
        uint256 glassesCount = descriptor.glassesCount();
        require(backgroundCount > 0, "background is missing");
        require(bodyCount > 0, "body is missing");
        require(accessoryCount > 0, "accessories is missing");
        require(headCount > 0, "head is missing");
        require(glassesCount > 0, "glasses is missing");

        return
            Seed({
                background: uint48(uint48(pseudorandomness) % backgroundCount),
                body: uint48(uint48(pseudorandomness >> 48) % bodyCount),
                accessory: uint48(
                    uint48(pseudorandomness >> 96) % accessoryCount
                ),
                head: uint48(uint48(pseudorandomness >> 144) % headCount),
                glasses: uint48(uint48(pseudorandomness >> 192) % glassesCount)
            });
    }
}

// File: /contracts/GNARDescriptor.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.6;

import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
import {Base64} from "base64-sol/base64.sol";
import {Strings} from "@openzeppelin/contracts/utils/Strings.sol";
import {IGnarDescriptor} from "../interfaces/IGNARDescriptor.sol";
import {IGnarSeeder} from "../interfaces/IGNARSeeder.sol";
import {MultiPartRLEToSVG} from "./libs/MultiPartRLEToSVG.sol";

contract GNARDescriptor is IGnarDescriptor, Ownable {
    using Strings for uint256;

    // Whether or not new Gnar parts can be added
    bool public override arePartsLocked;

    // Whether or not `tokenURI` should be returned as a data URI (Default: true)
    bool public override isDataURIEnabled = true;

    // Base URI
    string public override baseURI;

    // Gnar Color Palettes (Index => Hex Colors)
    mapping(uint8 => string[]) public override palettes;

    // Gnar Backgrounds (Hex Colors)
    string[] public override backgrounds;

    // Gnar Bodies (Custom RLE)
    bytes[] public override bodies;

    // Gnar Accessories (Custom RLE)
    bytes[] public override accessories;

    // Gnar Heads (Custom RLE)
    bytes[] public override heads;

    // Gnar Glasses (Custom RLE)
    bytes[] public override glasses;

    /**
     * @notice Require that the parts have not been locked.
     */
    modifier whenPartsNotLocked() {
        require(!arePartsLocked, "Parts are locked");
        _;
    }

    /**
     * @notice Get the number of available Gnar `backgrounds`.
     */
    function backgroundCount() external view override returns (uint256) {
        return backgrounds.length;
    }

    /**
     * @notice Get the number of available Gnar `bodies`.
     */
    function bodyCount() external view override returns (uint256) {
        return bodies.length;
    }

    /**
     * @notice Get the number of available Gnar `accessories`.
     */
    function accessoryCount() external view override returns (uint256) {
        return accessories.length;
    }

    /**
     * @notice Get the number of available Gnar `heads`.
     */
    function headCount() external view override returns (uint256) {
        return heads.length;
    }

    /**
     * @notice Get the number of available Gnar `glasses`.
     */
    function glassesCount() external view override returns (uint256) {
        return glasses.length;
    }

    /**
     * @notice Add colors to a color palette.
     * @dev This function can only be called by the owner.
     */
    function addManyColorsToPalette(
        uint8 paletteIndex,
        string[] calldata newColors
    ) external override onlyOwner {
        require(
            palettes[paletteIndex].length + newColors.length <= 256,
            "Palettes can only hold 256 colors"
        );
        for (uint256 i = 0; i < newColors.length; i++) {
            _addColorToPalette(paletteIndex, newColors[i]);
        }
    }

    /**
     * @notice Batch add Gnar backgrounds.
     * @dev This function can only be called by the owner when not locked.
     */
    function addManyBackgrounds(string[] calldata _backgrounds)
        external
        override
        onlyOwner
        whenPartsNotLocked
    {
        for (uint256 i = 0; i < _backgrounds.length; i++) {
            _addBackground(_backgrounds[i]);
        }
    }

    /**
     * @notice Batch add Gnar bodies.
     * @dev This function can only be called by the owner when not locked.
     */
    function addManyBodies(bytes[] calldata _bodies)
        external
        override
        onlyOwner
        whenPartsNotLocked
    {
        for (uint256 i = 0; i < _bodies.length; i++) {
            _addBody(_bodies[i]);
        }
    }

    /**
     * @notice Batch add Gnar accessories.
     * @dev This function can only be called by the owner when not locked.
     */
    function addManyAccessories(bytes[] calldata _accessories)
        external
        override
        onlyOwner
        whenPartsNotLocked
    {
        for (uint256 i = 0; i < _accessories.length; i++) {
            _addAccessory(_accessories[i]);
        }
    }

    /**
     * @notice Batch add Gnar heads.
     * @dev This function can only be called by the owner when not locked.
     */
    function addManyHeads(bytes[] calldata _heads)
        external
        override
        onlyOwner
        whenPartsNotLocked
    {
        for (uint256 i = 0; i < _heads.length; i++) {
            _addHead(_heads[i]);
        }
    }

    /**
     * @notice Batch add Gnar glasses.
     * @dev This function can only be called by the owner when not locked.
     */
    function addManyGlasses(bytes[] calldata _glasses)
        external
        override
        onlyOwner
        whenPartsNotLocked
    {
        for (uint256 i = 0; i < _glasses.length; i++) {
            _addGlasses(_glasses[i]);
        }
    }

    /**
     * @notice Add a single color to a color palette.
     * @dev This function can only be called by the owner.
     */
    function addColorToPalette(uint8 _paletteIndex, string calldata _color)
        external
        override
        onlyOwner
    {
        require(
            palettes[_paletteIndex].length <= 255,
            "Palettes can only hold 256 colors"
        );
        _addColorToPalette(_paletteIndex, _color);
    }

    /**
     * @notice Add a Gnar background.
     * @dev This function can only be called by the owner when not locked.
     */
    function addBackground(string calldata _background)
        external
        override
        onlyOwner
        whenPartsNotLocked
    {
        _addBackground(_background);
    }

    /**
     * @notice Add a Gnar body.
     * @dev This function can only be called by the owner when not locked.
     */
    function addBody(bytes calldata _body)
        external
        override
        onlyOwner
        whenPartsNotLocked
    {
        _addBody(_body);
    }

    /**
     * @notice Add a Gnar accessory.
     * @dev This function can only be called by the owner when not locked.
     */
    function addAccessory(bytes calldata _accessory)
        external
        override
        onlyOwner
        whenPartsNotLocked
    {
        _addAccessory(_accessory);
    }

    /**
     * @notice Add a Gnar head.
     * @dev This function can only be called by the owner when not locked.
     */
    function addHead(bytes calldata _head)
        external
        override
        onlyOwner
        whenPartsNotLocked
    {
        _addHead(_head);
    }

    /**
     * @notice Add Gnar glasses.
     * @dev This function can only be called by the owner when not locked.
     */
    function addGlasses(bytes calldata _glasses)
        external
        override
        onlyOwner
        whenPartsNotLocked
    {
        _addGlasses(_glasses);
    }

    /**
     * @notice Lock all Gnar parts.
     * @dev This cannot be reversed and can only be called by the owner when not locked.
     */
    function lockParts() external override onlyOwner whenPartsNotLocked {
        arePartsLocked = true;

        emit PartsLocked();
    }

    /**
     * @notice Toggle a boolean value which determines if `tokenURI` returns a data URI
     * or an HTTP URL.
     * @dev This can only be called by the owner.
     */
    function toggleDataURIEnabled() external override onlyOwner {
        bool enabled = !isDataURIEnabled;

        isDataURIEnabled = enabled;
        emit DataURIToggled(enabled);
    }

    /**
     * @notice Set the base URI for all token IDs. It is automatically
     * added as a prefix to the value returned in {tokenURI}, or to the
     * token ID if {tokenURI} is empty.
     * @dev This can only be called by the owner.
     */
    function setBaseURI(string calldata _baseURI) external override onlyOwner {
        baseURI = _baseURI;

        emit BaseURIUpdated(_baseURI);
    }

    /**
     * @notice Given a token ID and seed, construct a token URI for an official Gnars DAO Gnar.
     * @dev The returned value may be a base64 encoded data URI or an API URL.
     */
    function tokenURI(uint256 tokenId, IGnarSeeder.Seed memory seed)
        external
        view
        override
        returns (string memory)
    {
        if (isDataURIEnabled) {
            return dataURI(tokenId, seed);
        }
        return string(abi.encodePacked(baseURI, tokenId.toString()));
    }

    /**
     * @notice Given a token ID and seed, construct a base64 encoded data URI for an official Gnars DAO Gnar.
     */
    function dataURI(uint256 tokenId, IGnarSeeder.Seed memory seed)
        public
        view
        override
        returns (string memory)
    {
        string memory gnarId = tokenId.toString();
        string memory name = string(abi.encodePacked("Gnar ", gnarId));
        string memory description = string(
            abi.encodePacked("Gnar ", gnarId, " both skater and terrain")
        );

        return genericDataURI(name, description, seed);
    }

    /**
     * @notice Given a name, description, and seed, construct a base64 encoded data URI.
     */
    function genericDataURI(
        string memory name,
        string memory description,
        IGnarSeeder.Seed memory seed
    ) public view override returns (string memory) {
        string memory image = _generateSVGImage(
            MultiPartRLEToSVG.SVGParams({
                parts: _getPartsForSeed(seed),
                background: backgrounds[seed.background]
            })
        );

        // prettier-ignore
        return string(
            abi.encodePacked(
                'data:application/json;base64,',
                Base64.encode(
                    bytes(
                        abi.encodePacked('{"name":"', name, '", "description":"', description, '", "image": "', 'data:image/svg+xml;base64,', image, '"}')
                    )
                )
            )
        );
    }

    /**
     * @notice Given a seed, construct a base64 encoded SVG image.
     */
    function generateSVGImage(IGnarSeeder.Seed memory seed)
        external
        view
        override
        returns (string memory)
    {
        MultiPartRLEToSVG.SVGParams memory params = MultiPartRLEToSVG
            .SVGParams({
                parts: _getPartsForSeed(seed),
                background: backgrounds[seed.background]
            });
        return _generateSVGImage(params);
    }

    /**
     * @notice Generate an SVG image for use in the ERC721 token URI.
     */
    function _generateSVGImage(MultiPartRLEToSVG.SVGParams memory params)
        public
        view
        returns (string memory svg)
    {
        return
            Base64.encode(
                bytes(MultiPartRLEToSVG.generateSVG(params, palettes))
            );
    }

    /**
     * @notice Add a single color to a color palette.
     */
    function _addColorToPalette(uint8 _paletteIndex, string calldata _color)
        internal
    {
        palettes[_paletteIndex].push(_color);
    }

    /**
     * @notice Add a Gnar background.
     */
    function _addBackground(string calldata _background) internal {
        backgrounds.push(_background);
    }

    /**
     * @notice Add a Gnar body.
     */
    function _addBody(bytes calldata _body) internal {
        bodies.push(_body);
    }

    /**
     * @notice Add a Gnar accessory.
     */
    function _addAccessory(bytes calldata _accessory) internal {
        accessories.push(_accessory);
    }

    /**
     * @notice Add a Gnar head.
     */
    function _addHead(bytes calldata _head) internal {
        heads.push(_head);
    }

    /**
     * @notice Add Gnar glasses.
     */
    function _addGlasses(bytes calldata _glasses) internal {
        glasses.push(_glasses);
    }

    /**
     * @notice Get all Gnar parts for the passed `seed`.
     */
    function _getPartsForSeed(IGnarSeeder.Seed memory seed)
        internal
        view
        returns (bytes[] memory)
    {
        bytes[] memory _parts = new bytes[](4);
        _parts[0] = bodies[seed.body];
        _parts[1] = accessories[seed.accessory];
        _parts[2] = heads[seed.head];
        _parts[3] = glasses[seed.glasses];
        return _parts;
    }
}

// File: base64-sol/base64.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0;

/// @title Base64
/// @author Brecht Devos - <brecht@loopring.org>
/// @notice Provides functions for encoding/decoding base64
library Base64 {
    string internal constant TABLE_ENCODE = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
    bytes  internal constant TABLE_DECODE = hex"0000000000000000000000000000000000000000000000000000000000000000"
                                            hex"00000000000000000000003e0000003f3435363738393a3b3c3d000000000000"
                                            hex"00000102030405060708090a0b0c0d0e0f101112131415161718190000000000"
                                            hex"001a1b1c1d1e1f202122232425262728292a2b2c2d2e2f303132330000000000";

    function encode(bytes memory data) internal pure returns (string memory) {
        if (data.length == 0) return '';

        // load the table into memory
        string memory table = TABLE_ENCODE;

        // multiply by 4/3 rounded up
        uint256 encodedLen = 4 * ((data.length + 2) / 3);

        // add some extra buffer at the end required for the writing
        string memory result = new string(encodedLen + 32);

        assembly {
            // set the actual output length
            mstore(result, encodedLen)

            // prepare the lookup table
            let tablePtr := add(table, 1)

            // input ptr
            let dataPtr := data
            let endPtr := add(dataPtr, mload(data))

            // result ptr, jump over length
            let resultPtr := add(result, 32)

            // run over the input, 3 bytes at a time
            for {} lt(dataPtr, endPtr) {}
            {
                // read 3 bytes
                dataPtr := add(dataPtr, 3)
                let input := mload(dataPtr)

                // write 4 characters
                mstore8(resultPtr, mload(add(tablePtr, and(shr(18, input), 0x3F))))
                resultPtr := add(resultPtr, 1)
                mstore8(resultPtr, mload(add(tablePtr, and(shr(12, input), 0x3F))))
                resultPtr := add(resultPtr, 1)
                mstore8(resultPtr, mload(add(tablePtr, and(shr( 6, input), 0x3F))))
                resultPtr := add(resultPtr, 1)
                mstore8(resultPtr, mload(add(tablePtr, and(        input,  0x3F))))
                resultPtr := add(resultPtr, 1)
            }

            // padding with '='
            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;
    }

    function decode(string memory _data) internal pure returns (bytes memory) {
        bytes memory data = bytes(_data);

        if (data.length == 0) return new bytes(0);
        require(data.length % 4 == 0, "invalid base64 decoder input");

        // load the table into memory
        bytes memory table = TABLE_DECODE;

        // every 4 characters represent 3 bytes
        uint256 decodedLen = (data.length / 4) * 3;

        // add some extra buffer at the end required for the writing
        bytes memory result = new bytes(decodedLen + 32);

        assembly {
            // padding with '='
            let lastBytes := mload(add(data, mload(data)))
            if eq(and(lastBytes, 0xFF), 0x3d) {
                decodedLen := sub(decodedLen, 1)
                if eq(and(lastBytes, 0xFFFF), 0x3d3d) {
                    decodedLen := sub(decodedLen, 1)
                }
            }

            // set the actual output length
            mstore(result, decodedLen)

            // prepare the lookup table
            let tablePtr := add(table, 1)

            // input ptr
            let dataPtr := data
            let endPtr := add(dataPtr, mload(data))

            // result ptr, jump over length
            let resultPtr := add(result, 32)

            // run over the input, 4 characters at a time
            for {} lt(dataPtr, endPtr) {}
            {
               // read 4 characters
               dataPtr := add(dataPtr, 4)
               let input := mload(dataPtr)

               // write 3 bytes
               let output := add(
                   add(
                       shl(18, and(mload(add(tablePtr, and(shr(24, input), 0xFF))), 0xFF)),
                       shl(12, and(mload(add(tablePtr, and(shr(16, input), 0xFF))), 0xFF))),
                   add(
                       shl( 6, and(mload(add(tablePtr, and(shr( 8, input), 0xFF))), 0xFF)),
                               and(mload(add(tablePtr, and(        input , 0xFF))), 0xFF)
                    )
                )
                mstore(resultPtr, shl(232, output))
                resultPtr := add(resultPtr, 3)
            }
        }

        return result;
    }
}

// File: @openzeppelin/contracts/utils/introspection/IERC165.sol



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

pragma solidity ^0.8.0;

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

// File: @openzeppelin/contracts/utils/introspection/ERC165.sol



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

pragma solidity ^0.8.0;

import "./IERC165.sol";

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

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



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

pragma solidity ^0.8.0;

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

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

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

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

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

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



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

pragma solidity ^0.8.0;

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

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

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts 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: @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/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/extensions/ERC721Enumerable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/ERC721Enumerable.sol)

pragma solidity ^0.8.0;

import "../ERC721.sol";
import "./IERC721Enumerable.sol";

/**
 * @dev This implements an optional extension of {ERC721} defined in the EIP that adds
 * enumerability of all the token ids in the contract as well as all token ids owned by each
 * account.
 */
abstract contract ERC721Enumerable is ERC721, IERC721Enumerable {
    // Mapping from owner to list of owned token IDs
    mapping(address => mapping(uint256 => uint256)) private _ownedTokens;

    // Mapping from token ID to index of the owner tokens list
    mapping(uint256 => uint256) private _ownedTokensIndex;

    // Array with all token ids, used for enumeration
    uint256[] private _allTokens;

    // Mapping from token id to position in the allTokens array
    mapping(uint256 => uint256) private _allTokensIndex;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {
        return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721.balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
        return _ownedTokens[owner][index];
    }

    /**
     * @dev See {IERC721Enumerable-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _allTokens.length;
    }

    /**
     * @dev See {IERC721Enumerable-tokenByIndex}.
     */
    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721Enumerable.totalSupply(), "ERC721Enumerable: global index out of bounds");
        return _allTokens[index];
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * 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, ``from``'s `tokenId` will be burned.
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual override {
        super._beforeTokenTransfer(from, to, tokenId);

        if (from == address(0)) {
            _addTokenToAllTokensEnumeration(tokenId);
        } else if (from != to) {
            _removeTokenFromOwnerEnumeration(from, tokenId);
        }
        if (to == address(0)) {
            _removeTokenFromAllTokensEnumeration(tokenId);
        } else if (to != from) {
            _addTokenToOwnerEnumeration(to, tokenId);
        }
    }

    /**
     * @dev Private function to add a token to this extension's ownership-tracking data structures.
     * @param to address representing the new owner of the given token ID
     * @param tokenId uint256 ID of the token to be added to the tokens list of the given address
     */
    function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {
        uint256 length = ERC721.balanceOf(to);
        _ownedTokens[to][length] = tokenId;
        _ownedTokensIndex[tokenId] = length;
    }

    /**
     * @dev Private function to add a token to this extension's token tracking data structures.
     * @param tokenId uint256 ID of the token to be added to the tokens list
     */
    function _addTokenToAllTokensEnumeration(uint256 tokenId) private {
        _allTokensIndex[tokenId] = _allTokens.length;
        _allTokens.push(tokenId);
    }

    /**
     * @dev Private function to remove a token from this extension's ownership-tracking data structures. Note that
     * while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for
     * gas optimizations e.g. when performing a transfer operation (avoiding double writes).
     * This has O(1) time complexity, but alters the order of the _ownedTokens array.
     * @param from address representing the previous owner of the given token ID
     * @param tokenId uint256 ID of the token to be removed from the tokens list of the given address
     */
    function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {
        // To prevent a gap in from's tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).

        uint256 lastTokenIndex = ERC721.balanceOf(from) - 1;
        uint256 tokenIndex = _ownedTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary
        if (tokenIndex != lastTokenIndex) {
            uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];

            _ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
            _ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
        }

        // This also deletes the contents at the last position of the array
        delete _ownedTokensIndex[tokenId];
        delete _ownedTokens[from][lastTokenIndex];
    }

    /**
     * @dev Private function to remove a token from this extension's token tracking data structures.
     * This has O(1) time complexity, but alters the order of the _allTokens array.
     * @param tokenId uint256 ID of the token to be removed from the tokens list
     */
    function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {
        // To prevent a gap in the tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).

        uint256 lastTokenIndex = _allTokens.length - 1;
        uint256 tokenIndex = _allTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so
        // rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding
        // an 'if' statement (like in _removeTokenFromOwnerEnumeration)
        uint256 lastTokenId = _allTokens[lastTokenIndex];

        _allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
        _allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index

        // This also deletes the contents at the last position of the array
        delete _allTokensIndex[tokenId];
        _allTokens.pop();
    }
}

// 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/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/ERC721.sol



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

pragma solidity ^0.8.0;

import "./IERC721.sol";
import "./IERC721Receiver.sol";
import "./extensions/IERC721Metadata.sol";
import "../../utils/Address.sol";
import "../../utils/Context.sol";
import "../../utils/Strings.sol";
import "../../utils/introspection/ERC165.sol";

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension, but not including the Enumerable extension, which is available separately as
 * {ERC721Enumerable}.
 */
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Mapping from token ID to owner address
    mapping(uint256 => address) private _owners;

    // Mapping owner address to token count
    mapping(address => uint256) private _balances;

    // Mapping from token ID to approved address
    mapping(uint256 => address) private _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 ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: balance query for the zero address");
        return _balances[owner];
    }

    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _owners[tokenId];
        require(owner != address(0), "ERC721: 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");

        string memory baseURI = _baseURI();
        return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
    }

    /**
     * @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, can be overriden in child contracts.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return "";
    }

    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ERC721.ownerOf(tokenId);
        require(to != owner, "ERC721: approval to current owner");

        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            "ERC721: 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), "ERC721: 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 {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: 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), "ERC721: 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), "ERC721: 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 _owners[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), "ERC721: operator query for nonexistent token");
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
    }

    /**
     * @dev Safely mints `tokenId` and transfers it to `to`.
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - 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, uint256 tokenId) internal virtual {
        _safeMint(to, tokenId, "");
    }

    /**
     * @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,
        uint256 tokenId,
        bytes memory _data
    ) internal virtual {
        _mint(to, tokenId);
        require(
            _checkOnERC721Received(address(0), to, tokenId, _data),
            "ERC721: 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:
     *
     * - `tokenId` must not exist.
     * - `to` cannot be the zero address.
     *
     * Emits a {Transfer} event.
     */
    function _mint(address to, uint256 tokenId) internal virtual {
        require(to != address(0), "ERC721: mint to the zero address");
        require(!_exists(tokenId), "ERC721: token already minted");

        _beforeTokenTransfer(address(0), to, tokenId);

        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(address(0), to, 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 = ERC721.ownerOf(tokenId);

        _beforeTokenTransfer(owner, address(0), tokenId);

        // Clear approvals
        _approve(address(0), tokenId);

        _balances[owner] -= 1;
        delete _owners[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(ERC721.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own");
        require(to != address(0), "ERC721: transfer to the zero address");

        _beforeTokenTransfer(from, to, tokenId);

        // Clear approvals from the previous owner
        _approve(address(0), tokenId);

        _balances[from] -= 1;
        _balances[to] += 1;
        _owners[tokenId] = to;

        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(ERC721.ownerOf(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, "ERC721: 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("ERC721: transfer to non ERC721Receiver implementer");
                } else {
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * 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, ``from``'s `tokenId` will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {}
}

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

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

// File: @openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;
import "../proxy/utils/Initializable.sol";

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuardUpgradeable is Initializable {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    function __ReentrancyGuard_init() internal onlyInitializing {
        __ReentrancyGuard_init_unchained();
    }

    function __ReentrancyGuard_init_unchained() internal onlyInitializing {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
    uint256[49] private __gap;
}

// File: @openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol



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

pragma solidity ^0.8.0;

import "../../utils/AddressUpgradeable.sol";

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 *
 * [CAUTION]
 * ====
 * Avoid leaving a contract uninitialized.
 *
 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
 * contract, which may impact the proxy. To initialize the implementation contract, you can either invoke the
 * initializer manually, or you can include a constructor to automatically mark it as initialized when it is deployed:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * /// @custom:oz-upgrades-unsafe-allow constructor
 * constructor() initializer {}
 * ```
 * ====
 */
abstract contract Initializable {
    /**
     * @dev Indicates that the contract has been initialized.
     */
    bool private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Modifier to protect an initializer function from being invoked twice.
     */
    modifier initializer() {
        // If the contract is initializing we ignore whether _initialized is set in order to support multiple
        // inheritance patterns, but we only do this in the context of a constructor, because in other contexts the
        // contract may have been reentered.
        require(_initializing ? _isConstructor() : !_initialized, "Initializable: contract is already initialized");

        bool isTopLevelCall = !_initializing;
        if (isTopLevelCall) {
            _initializing = true;
            _initialized = true;
        }

        _;

        if (isTopLevelCall) {
            _initializing = false;
        }
    }

    /**
     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
     * {initializer} modifier, directly or indirectly.
     */
    modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
    }

    function _isConstructor() private view returns (bool) {
        return !AddressUpgradeable.isContract(address(this));
    }
}