// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (access/AccessControl.sol)

pragma solidity ^0.8.0;

import "./IAccessControlUpgradeable.sol";
import "../utils/ContextUpgradeable.sol";
import "../utils/StringsUpgradeable.sol";
import "../utils/introspection/ERC165Upgradeable.sol";
import "../proxy/utils/Initializable.sol";

/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms. This is a lightweight version that doesn't allow enumerating role
 * members except through off-chain means by accessing the contract event logs. Some
 * applications may benefit from on-chain enumerability, for those cases see
 * {AccessControlEnumerable}.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControlUpgradeable is Initializable, ContextUpgradeable, IAccessControlUpgradeable, ERC165Upgradeable {
    function __AccessControl_init() internal initializer {
        __Context_init_unchained();
        __ERC165_init_unchained();
        __AccessControl_init_unchained();
    }

    function __AccessControl_init_unchained() internal initializer {
    }
    struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
    }

    mapping(bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

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

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

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

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

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

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

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

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

        _revokeRole(role, account);
    }

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

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

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

    /**
     * @dev Revokes `role` from `account`.
     *
     * Internal function without access restriction.
     */
    function _revokeRole(bytes32 role, address account) internal virtual {
        if (hasRole(role, account)) {
            _roles[role].members[account] = false;
            emit RoleRevoked(role, account, _msgSender());
        }
    }
    uint256[49] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (access/IAccessControl.sol)

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/ContextUpgradeable.sol";
import "../proxy/utils/Initializable.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 OwnableUpgradeable is Initializable, ContextUpgradeable {
    address private _owner;

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    function __Ownable_init() internal initializer {
        __Context_init_unchained();
        __Ownable_init_unchained();
    }

    function __Ownable_init_unchained() internal initializer {
        _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);
    }
    uint256[49] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (proxy/utils/Initializable.sol)

pragma solidity ^0.8.0;

/**
 * @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() {
        require(_initializing || !_initialized, "Initializable: contract is already initialized");

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

        _;

        if (isTopLevelCall) {
            _initializing = false;
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (token/ERC721/ERC721.sol)

pragma solidity ^0.8.0;

import "./IERC721Upgradeable.sol";
import "./IERC721ReceiverUpgradeable.sol";
import "./extensions/IERC721MetadataUpgradeable.sol";
import "../../utils/AddressUpgradeable.sol";
import "../../utils/ContextUpgradeable.sol";
import "../../utils/StringsUpgradeable.sol";
import "../../utils/introspection/ERC165Upgradeable.sol";
import "../../proxy/utils/Initializable.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 ERC721Upgradeable is Initializable, ContextUpgradeable, ERC165Upgradeable, IERC721Upgradeable, IERC721MetadataUpgradeable {
    using AddressUpgradeable for address;
    using StringsUpgradeable 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.
     */
    function __ERC721_init(string memory name_, string memory symbol_) internal initializer {
        __Context_init_unchained();
        __ERC165_init_unchained();
        __ERC721_init_unchained(name_, symbol_);
    }

    function __ERC721_init_unchained(string memory name_, string memory symbol_) internal initializer {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165Upgradeable, IERC165Upgradeable) returns (bool) {
        return
            interfaceId == type(IERC721Upgradeable).interfaceId ||
            interfaceId == type(IERC721MetadataUpgradeable).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 = ERC721Upgradeable.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 = ERC721Upgradeable.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 = ERC721Upgradeable.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(ERC721Upgradeable.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(ERC721Upgradeable.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 IERC721ReceiverUpgradeable(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
                return retval == IERC721ReceiverUpgradeable.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 {}
    uint256[44] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (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 IERC721ReceiverUpgradeable {
    /**
     * @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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165Upgradeable.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721Upgradeable is IERC165Upgradeable {
    /**
     * @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;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (token/ERC721/extensions/ERC721Enumerable.sol)

pragma solidity ^0.8.0;

import "../ERC721Upgradeable.sol";
import "./IERC721EnumerableUpgradeable.sol";
import "../../../proxy/utils/Initializable.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 ERC721EnumerableUpgradeable is Initializable, ERC721Upgradeable, IERC721EnumerableUpgradeable {
    function __ERC721Enumerable_init() internal initializer {
        __Context_init_unchained();
        __ERC165_init_unchained();
        __ERC721Enumerable_init_unchained();
    }

    function __ERC721Enumerable_init_unchained() internal initializer {
    }
    // 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(IERC165Upgradeable, ERC721Upgradeable) returns (bool) {
        return interfaceId == type(IERC721EnumerableUpgradeable).interfaceId || super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721Upgradeable.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 < ERC721EnumerableUpgradeable.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 = ERC721Upgradeable.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 = ERC721Upgradeable.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();
    }
    uint256[46] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (token/ERC721/extensions/IERC721Enumerable.sol)

pragma solidity ^0.8.0;

import "../IERC721Upgradeable.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721EnumerableUpgradeable is IERC721Upgradeable {
    /**
     * @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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (token/ERC721/extensions/IERC721Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC721Upgradeable.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721MetadataUpgradeable is IERC721Upgradeable {
    /**
     * @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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (token/ERC721/utils/ERC721Holder.sol)

pragma solidity ^0.8.0;

import "../IERC721ReceiverUpgradeable.sol";
import "../../../proxy/utils/Initializable.sol";

/**
 * @dev Implementation of the {IERC721Receiver} interface.
 *
 * Accepts all token transfers.
 * Make sure the contract is able to use its token with {IERC721-safeTransferFrom}, {IERC721-approve} or {IERC721-setApprovalForAll}.
 */
contract ERC721HolderUpgradeable is Initializable, IERC721ReceiverUpgradeable {
    function __ERC721Holder_init() internal initializer {
        __ERC721Holder_init_unchained();
    }

    function __ERC721Holder_init_unchained() internal initializer {
    }
    /**
     * @dev See {IERC721Receiver-onERC721Received}.
     *
     * Always returns `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address,
        address,
        uint256,
        bytes memory
    ) public virtual override returns (bytes4) {
        return this.onERC721Received.selector;
    }
    uint256[50] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (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);
            }
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (utils/Context.sol)

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

/**
 * @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 ContextUpgradeable is Initializable {
    function __Context_init() internal initializer {
        __Context_init_unchained();
    }

    function __Context_init_unchained() internal initializer {
    }
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
    uint256[50] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (utils/Strings.sol)

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library StringsUpgradeable {
    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);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;

import "./IERC165Upgradeable.sol";
import "../../proxy/utils/Initializable.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 ERC165Upgradeable is Initializable, IERC165Upgradeable {
    function __ERC165_init() internal initializer {
        __ERC165_init_unchained();
    }

    function __ERC165_init_unchained() internal initializer {
    }
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165Upgradeable).interfaceId;
    }
    uint256[50] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (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 IERC165Upgradeable {
    /**
     * @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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (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);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (utils/math/SafeMath.sol)

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
            // benefit is lost if 'b' is also tested.
            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity 0.8.7;

import "@openzeppelin/contracts-upgradeable/access/AccessControlUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC721/extensions/ERC721EnumerableUpgradeable.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";

/**
 * @title Digital art collectible metaverse
 * @author NFT Legends team
 **/
contract Collection is ERC721Upgradeable, ERC721EnumerableUpgradeable, AccessControlUpgradeable {
    event NameChange(uint256 indexed index, string newName);
    event SkillChange(uint256 indexed index, uint256 newSkill);
    event DnaChange(uint256 indexed index, uint256 newDna);
    event Buy(address indexed _from, uint256 nfts, address referral);

    // each token has its own attributes: Name, Skill and DNA
    // Name is the symbolic string, that can be changed over time
    mapping(uint256 => string) private _tokenName;
    // Skill is a numeric value that represents character's experience
    mapping(uint256 => uint256) private _tokenSkill;
    // DNA is 256-bit map where unique token attributes encoded
    mapping(uint256 => uint256) private _tokenDna;

    // when sale is active, anyone is able to buy the token
    bool public saleActive;

    using SafeMath for uint256;
    using Strings for uint256;

    // The token purchase price depends on how early you buy the character
    // (i.e. sequential number of the purchase)
    struct SaleStage {
        uint256 startTokensBought;
        uint256 endTokensBought;
        uint256 weiPerToken;
    }

    // All the tokens are grouped in batches. Batch is basically IPFS folder (DAG)
    // that stores token descriptions and images. It tokenId falls into batch, the
    // tokenURI = batch.baseURI + "/" + tokenId.
    // All the batches have the same rarity parameter.
    struct Batch {
        uint256 startBatchTokenId;
        uint256 endBatchTokenId;
        string baseURI;
        uint256 rarity;
    }

    // Arrays that store configured batches and saleStages
    Batch[] internal _batches;
    SaleStage[] internal _saleStages;
    // Maximum allowed tokenSupply boundary. Can be extended by adding new stages.
    uint256 internal _maxTotalSupply;
    // Max NFTs that can be bought at once. To avoid gas overspending.
    uint256 public maxPurchaseSize;

    // If tokenId doesn't match any configured batch, defaultURI parameters are used.
    string internal _defaultUri;
    uint256 internal _defaultRarity;
    string internal _defaultName;
    uint256 internal _defaultSkill;
    // Roles that can modify individual characteristics
    bytes32 public constant NAME_SETTER_ROLE = keccak256("NAME_SETTER_ROLE");
    bytes32 public constant SKILL_SETTER_ROLE = keccak256("SKILL_SETTER_ROLE");
    bytes32 public constant DNA_SETTER_ROLE = keccak256("DNA_SETTER_ROLE");
    bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
    // Received funds (native Ether or BNB) get transferred to Vault address
    address payable public vault;

    function initialize() public initializer {
        __ERC721_init("CyberPunk", "A-12");
        __ERC721Enumerable_init();
        __AccessControl_init();

        _setupRole(DEFAULT_ADMIN_ROLE, _msgSender());
        _setupRole(NAME_SETTER_ROLE, _msgSender());
        _setupRole(SKILL_SETTER_ROLE, _msgSender());
        _setupRole(DNA_SETTER_ROLE, _msgSender());
        _setupRole(MINTER_ROLE, _msgSender());
        maxPurchaseSize = 20;
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override(ERC721Upgradeable, ERC721EnumerableUpgradeable, AccessControlUpgradeable)
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }

    /**
     * @dev Returns current `_maxTotalSupply` value.
     */
    function maxTotalSupply() public view virtual returns (uint256) {
        return _maxTotalSupply;
    }

    /**
     * @dev Hook that is called before any token transfer incl. minting
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual override(ERC721Upgradeable, ERC721EnumerableUpgradeable) {
        super._beforeTokenTransfer(from, to, tokenId);

        // check maxTotalSupply is not exceeded on mint
        if (from == address(0)) {
            require(totalSupply() <= _maxTotalSupply, "Collection: maxSupply achieved");
        }
    }

    /**
     * @dev Returns the number of configured saleStages (tokensale schedule)
     * @return current `_saleStages` array length
     */
    function saleStagesLength() public view returns (uint256) {
        return _saleStages.length;
    }

    /**
     * @dev Returns the saleStage by its index
     * @param saleStageIndex salestage index in the array
     * @return info about sale stage
     */
    function getSaleStage(uint256 saleStageIndex) public view returns (SaleStage memory) {
        require(_saleStages.length > 0, "getSaleStage: no stages");
        require(saleStageIndex < _saleStages.length, "Id must be < sale stages length");

        return _saleStages[saleStageIndex];
    }

    /**
     * @dev Returns the length of configured batches
     * @return current `_batches` array length.
     */
    function batchesLength() public view returns (uint256) {
        return _batches.length;
    }

    /**
     * @dev Returns all the batches
     * @return `_batches`.
     */
    function getBatches() public view returns (Batch[] memory) {
        return _batches;
    }

    /**
     * @dev Returns all sale stages
     * @return `_saleStages`.
     */
    function getSaleStages() public view returns (SaleStage[] memory) {
        return _saleStages;
    }

    /**
     * @dev Returns the batch by its index in the array
     * @param batchIndex batch index
     * @return Batch info
     * Note: batch ids can change over time and reorder as the result of batch removal
     */
    function getBatch(uint256 batchIndex) public view returns (Batch memory) {
        require(_batches.length > 0, "getBatch: no batches");
        require(batchIndex < _batches.length, "Id must be < batch length");

        return _batches[batchIndex];
    }

    /**
     * @dev Return batch by given tokenId
     * @param tokenId token id
     * @return batch structure
     */
    function getBatchByToken(uint256 tokenId) public view returns (Batch memory) {
        require(_batches.length > 0, "getBatchByToken: no batches");

        for (uint256 i; i < _batches.length; i++) {
            if (tokenId > _batches[i].endBatchTokenId || tokenId < _batches[i].startBatchTokenId) {
                continue;
            } else {
                return _batches[i];
            }
        }
        revert("batch doesn't exist");
    }

    /**
     * @dev IPFS address that stores JSON with token attributes
     * Tries to find it by batch first. If token has no batch, returns defaultUri.
     * @param tokenId id of the token
     * @return string with ipfs address to json with token attribute
     * or URI for default token if token doesn`t exist
     */
    function tokenURI(uint256 tokenId) public view override returns (string memory) {
        require(_batches.length > 0, "tokenURI: no batches");

        for (uint256 i; i < _batches.length; i++) {
            if (tokenId > _batches[i].endBatchTokenId || tokenId < _batches[i].startBatchTokenId) {
                continue;
            } else {
                return string(abi.encodePacked(_batches[i].baseURI, "/", tokenId.toString(), ".json"));
            }
        }
        return _defaultUri;
    }

    /**
     * @notice Creates the new batch for given token range
     * @param startTokenId index of the first batch token
     * @param endTokenId index of the last batch token
     * @param baseURI ipfs batch URI
     * @param rarity batch rarity
     * Note: batch ids can change over time and reorder as the result of batch removal
     */
    function addBatch(
        uint256 startTokenId,
        uint256 endTokenId,
        string memory baseURI,
        uint256 rarity
    ) external onlyRole(DEFAULT_ADMIN_ROLE) {
        uint256 _batchesLength = _batches.length;

        require(startTokenId <= endTokenId, "startId must be <= than EndId");
        if (_batchesLength > 0) {
            for (uint256 i; i < _batchesLength; i++) {
                // if both bounds are lower or higher than iter batch
                if (
                    (startTokenId < _batches[i].startBatchTokenId && endTokenId < _batches[i].startBatchTokenId) ||
                    (startTokenId > _batches[i].endBatchTokenId && endTokenId > _batches[i].endBatchTokenId)
                ) {
                    continue;
                } else {
                    revert("batches intersect");
                }
            }
        }

        _batches.push(Batch(startTokenId, endTokenId, baseURI, rarity));
    }

    /**
     * @notice Update existing batch by its index
     * @param batchIndex the index of the batch to be changed
     * @param batchStartId index of the first batch token
     * @param batchEndId index of the last batch token
     * @param baseURI ipfs batch URI
     * @param rarity batch rarity
     * Note: batch ids can change over time and reorder as the result of batch removal
     */
    function setBatch(
        uint256 batchIndex,
        uint256 batchStartId,
        uint256 batchEndId,
        string memory baseURI,
        uint256 rarity
    ) external onlyRole(DEFAULT_ADMIN_ROLE) {
        uint256 _batchesLength = _batches.length;
        require(_batchesLength > 0, "setBatch: batches is empty");
        require(batchStartId <= batchEndId, "startId must be <= than EndId");

        for (uint256 i; i < _batchesLength; i++) {
            if (i == batchIndex) {
                continue;
            } else {
                // if both bounds are lower or higher than iter batch
                if (
                    (batchStartId < _batches[i].startBatchTokenId && batchEndId < _batches[i].startBatchTokenId) ||
                    (batchStartId > _batches[i].endBatchTokenId && batchEndId > _batches[i].endBatchTokenId)
                ) {
                    continue;
                } else {
                    revert("batches intersect");
                }
            }
        }

        _batches[batchIndex].startBatchTokenId = batchStartId;
        _batches[batchIndex].endBatchTokenId = batchEndId;
        _batches[batchIndex].baseURI = baseURI;
        _batches[batchIndex].rarity = rarity;
    }

    /**
     * @notice Deletes batch by its id. This reorders the index of the token that was last.
     * @param batchIndex the index of the batch to be deteted
     */
    function deleteBatch(uint256 batchIndex) external onlyRole(DEFAULT_ADMIN_ROLE) {
        require(_batches.length > batchIndex, "index out of batches length");
        _batches[batchIndex] = _batches[_batches.length - 1];
        _batches.pop();
    }

    /**
     * @notice Add sale stage (i.e. tokensale schedule)
     * It takes place at the end of `saleStages array`
     * @param startTokensBought index of the first batch token
     * @param endTokensBought index of the last batch token
     * @param weiPerToken price for token
     */
    function addSaleStage(
        uint256 startTokensBought,
        uint256 endTokensBought,
        uint256 weiPerToken
    ) external onlyRole(DEFAULT_ADMIN_ROLE) {
        require(startTokensBought <= endTokensBought, "startTokensBought must be <= than endTokensBought");
        require(weiPerToken > 0, "weiPerToken must be non-zero");
        uint256 _saleStagesLength = _saleStages.length;

        if (_saleStagesLength > 0) {
            for (uint256 i; i < _saleStagesLength; i++) {
                // if both bounds are lower or higher than iter sale stage
                if (
                    (startTokensBought < _saleStages[i].startTokensBought &&
                        endTokensBought < _saleStages[i].startTokensBought) ||
                    (startTokensBought > _saleStages[i].endTokensBought &&
                        endTokensBought > _saleStages[i].endTokensBought)
                ) {
                    continue;
                } else {
                    revert("intersection _saleStages");
                }
            }
        }

        _saleStages.push(SaleStage(startTokensBought, endTokensBought, weiPerToken));
        _maxTotalSupply += endTokensBought - startTokensBought + 1;
    }

    /**
     * @notice Update (rewrite) saleStage properties by index
     * @param saleStageId index of the first sale stage token
     * @param startTokensBought index of the first batch token
     * @param endTokensBought index of the last batch token
     * @param weiPerToken price for token
     */
    function setSaleStage(
        uint256 saleStageId,
        uint256 startTokensBought,
        uint256 endTokensBought,
        uint256 weiPerToken
    ) external onlyRole(DEFAULT_ADMIN_ROLE) {
        uint256 _saleStagesLength = _saleStages.length;
        require(_saleStagesLength > 0, "batches is empty");
        require(startTokensBought <= endTokensBought, "startId must be <= than EndId");
        for (uint256 i; i < _saleStagesLength; i++) {
            if (i == saleStageId) {
                continue;
            } else {
                // if both bounds are lower or higher than iter sale stage
                if (
                    (startTokensBought < _saleStages[i].startTokensBought &&
                        endTokensBought < _saleStages[i].startTokensBought) ||
                    (startTokensBought > _saleStages[i].endTokensBought &&
                        endTokensBought > _saleStages[i].endTokensBought)
                ) {
                    continue;
                } else {
                    revert("intersection _saleStages");
                }
            }
        }
        SaleStage memory _saleStage = _saleStages[saleStageId];
        _maxTotalSupply =
            _maxTotalSupply -
            (_saleStage.endTokensBought - _saleStage.startTokensBought + 1) +
            (endTokensBought - startTokensBought + 1);

        _saleStages[saleStageId].startTokensBought = startTokensBought;
        _saleStages[saleStageId].endTokensBought = endTokensBought;
        _saleStages[saleStageId].weiPerToken = weiPerToken;
    }

    /**
     * @dev Delete sale stage by the given given index
     * @param saleStageIndex index of the batch to be deleted
     */
    function deleteSaleStage(uint256 saleStageIndex) external onlyRole(DEFAULT_ADMIN_ROLE) {
        require(_saleStages.length > saleStageIndex, "index out of sale stage length");
        SaleStage memory _saleStage = _saleStages[saleStageIndex];
        _maxTotalSupply -= _saleStage.endTokensBought - _saleStage.startTokensBought + 1;

        _saleStages[saleStageIndex] = _saleStages[_saleStages.length - 1];
        _saleStages.pop();
    }

    /**
     * @dev Calculates the total price for the given number of tokens
     * @param tokens number of tokens to be purchased
     * @return summary price
     */
    function getTotalPriceFor(uint256 tokens) public view returns (uint256) {
        require(tokens > 0, "tokens must be more then 0");

        uint256 _saleStagesLength = _saleStages.length;
        uint256 totalSupply = totalSupply();
        uint256 iterPrice = 0;
        uint256 totalPrice = 0;

        SaleStage memory saleStage;
        for (uint256 tokenIndex = 0; tokenIndex < tokens; tokenIndex++) {
            iterPrice = 0;
            for (uint256 i = 0; i < _saleStagesLength; i++) {
                saleStage = _saleStages[i];
                if (totalSupply > saleStage.endTokensBought || totalSupply < saleStage.startTokensBought) continue;
                iterPrice += saleStage.weiPerToken;
            }
            if (iterPrice == 0) {
                revert("saleStage doesn't exist");
            }
            totalPrice += iterPrice;
            totalSupply += 1;
        }
        return totalPrice;
    }

    /**
     * @dev Method to randomly mint desired number of NFTs
     * @param to the address where you want to transfer tokens
     * @param nfts the number of tokens to be minted
     */
    function _mintMultiple(address to, uint256 nfts) internal {
        require(totalSupply() < _maxTotalSupply, "Sale has already ended");
        require(nfts > 0, "nfts cannot be 0");
        require(totalSupply().add(nfts) <= _maxTotalSupply, "Exceeds _maxTotalSupply");

        for (uint256 i = 0; i < nfts; i++) {
            uint256 mintIndex = _getRandomAvailableIndex();
            _safeMint(to, mintIndex);
        }
    }

    /**
     * @dev Mints a specific token (with known id) to the given address
     * @param to the receiver
     * @param mintIndex the tokenId to mint
     */
    function mint(address to, uint256 mintIndex) public onlyRole(MINTER_ROLE) {
        _safeMint(to, mintIndex);
    }

    /**
     * @dev Public method to randomly mint desired number of NFTs
     * @param to the receiver
     * @param nfts the number of tokens to be minted
     */
    function mintMultiple(address to, uint256 nfts) public onlyRole(MINTER_ROLE) {
        _mintMultiple(to, nfts);
    }

    /**
     * @dev Method to purchase and random available NFTs.
     * @param nfts the number of tokens to buy
     * @param referral the address of referral who invited the user to the platform
     */
    function buy(uint256 nfts, address referral) public payable {
        require(saleActive, "Sale is not active");
        require(nfts <= maxPurchaseSize, "Can not buy > maxPurchaseSize");
        require(getTotalPriceFor(nfts) == msg.value, "Ether value sent is not correct");
        emit Buy(msg.sender, nfts, referral);
        vault.transfer(msg.value);
        _mintMultiple(msg.sender, nfts);
    }

    /**
     * @dev Returns the (pseudo-)random token index free of owner.
     * @return available token index
     */
    function _getRandomAvailableIndex() internal view returns (uint256) {
        uint256 index = (uint256(
            keccak256(
                abi.encodePacked(
                    block.timestamp, /* solhint-disable not-rely-on-time */
                    gasleft(),
                    blockhash(block.number - 1)
                )
            )
        ) % _maxTotalSupply);
        while (_exists(index)) {
            index += 1;
            if (index >= _maxTotalSupply) {
                index = 0;
            }
        }
        return index;
    }

    /**
     * @dev Returns rarity of the NFT by token Id
     * @param tokenId id of the token
     * @return rarity
     */
    function getRarity(uint256 tokenId) public view returns (uint256) {
        require(_batches.length > 0, "getBatchByToken: no batches");

        for (uint256 i; i < _batches.length; i++) {
            if (tokenId > _batches[i].endBatchTokenId || tokenId < _batches[i].startBatchTokenId) {
                continue;
            } else {
                return _batches[i].rarity;
            }
        }
        return _defaultRarity;
    }

    /**
     * @dev Returns name of the NFT at index
     * @param index token id
     * @return NFT name
     */
    function getName(uint256 index) public view returns (string memory) {
        require(index < _maxTotalSupply, "index < _maxTotalSupply");
        bytes memory _tokenWeight = bytes(_tokenName[index]);
        if (_tokenWeight.length == 0) {
            return _defaultName;
        }
        return _tokenName[index];
    }

    /**
     * @dev Returns skill of the NFT at index
     * @param index token id
     * @return NFT skill
     */
    function getSkill(uint256 index) public view returns (uint256) {
        require(index < _maxTotalSupply, "index < _maxTotalSupply");
        if (_tokenSkill[index] == 0) {
            return _defaultSkill;
        }
        return _tokenSkill[index];
    }

    /**
     * @dev Returns individual DNA of the NFT at index
     * @param index token id
     * @return NFT DNA
     */
    function getDna(uint256 index) public view returns (uint256) {
        require(index < _maxTotalSupply, "index < _maxTotalSupply");
        return _tokenDna[index];
    }

    /**
     * @dev Start tokensale process
     */
    function start() public onlyRole(DEFAULT_ADMIN_ROLE) {
        require(bytes(_defaultUri).length > 0, "_defaultUri is undefined");
        require(vault != address(0), "Vault is undefined");
        saleActive = true;
    }

    /**
     * @dev Stop tokensale
     */
    function stop() public onlyRole(DEFAULT_ADMIN_ROLE) {
        saleActive = false;
    }

    /**
     * @dev Set or change individual token name
     */
    function setName(uint256 index, string memory newName) public onlyRole(NAME_SETTER_ROLE) {
        require(index < _maxTotalSupply, "index < _maxTotalSupply");
        _tokenName[index] = newName;
        emit NameChange(index, newName);
    }

    /**
     * @dev Set or change individual token skill
     */
    function setSkill(uint256 index, uint256 newSkill) public onlyRole(SKILL_SETTER_ROLE) {
        require(index < _maxTotalSupply, "index < _maxTotalSupply");
        _tokenSkill[index] = newSkill;
        emit SkillChange(index, newSkill);
    }

    /**
     * @dev Set or change individual token DNA
     */
    function setDna(uint256 index, uint256 newDna) public onlyRole(DNA_SETTER_ROLE) {
        require(index < _maxTotalSupply, "index < _maxTotalSupply");
        _tokenDna[index] = newDna;
        emit DnaChange(index, newDna);
    }

    /**
     * @dev Set max purchase size (to avoid gas overspending)
     */
    function setMaxPurchaseSize(uint256 newPurchaseSize) public onlyRole(DEFAULT_ADMIN_ROLE) {
        maxPurchaseSize = newPurchaseSize;
    }

    /**
     * @dev Set defaultUri
     */
    function setDefaultUri(string memory uri) public onlyRole(DEFAULT_ADMIN_ROLE) {
        _defaultUri = uri;
    }

    /**
     * @dev Set vault
     * @param newVault address to receive ethers
     */
    function setVault(address payable newVault) public onlyRole(DEFAULT_ADMIN_ROLE) {
        vault = newVault;
    }

    /**
     * @dev Set defaultRarity
     * @param rarity new default rarity
     */
    function setDefaultRarity(uint256 rarity) public onlyRole(DEFAULT_ADMIN_ROLE) {
        _defaultRarity = rarity;
    }

    /**
     * @dev Set default name.
     * @param name new default name
     */
    function setDefaultName(string memory name) public onlyRole(DEFAULT_ADMIN_ROLE) {
        _defaultName = name;
    }

    /**
     * @dev Set default skill.
     * @param skill new default name
     */
    function setDefaultSkill(uint256 skill) public onlyRole(DEFAULT_ADMIN_ROLE) {
        _defaultSkill = skill;
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC721/utils/ERC721HolderUpgradeable.sol";
import "./Collection.sol";

contract NFTStaking is OwnableUpgradeable, ERC721HolderUpgradeable {
    // user deposits are recorded in StakeInfo[] stakes struct
    struct StakeInfo {
        // staked is true if token is staked and hasn't been unstaked.
        // After user claims his stake back, `staked` becomes false
        bool staked;
        // address of staked token's owner
        address stakerAddress;
        // time of start staking token
        uint256 lastUpdateTime;
        // totalYield is a total value of rewards for the given stake.
        // user is able to withdraw yield.
        uint256 totalYield;
        // The amount of yield user already harvested
        uint256 harvestedYield;
    }

    // If stakesOpen == true, the contract is operational and accepts new stakes.
    // Otherwise it allows just harvesting and unstaking.
    bool public stakesOpen;

    // Token used for rewards
    IERC20 public nftlToken;

    // The token accepted for staking
    Collection public heroesToken;

    uint256 internal constant WELCOME_BONUS_TIME = 365 * 24 * 60 * 60;

    // struccture that stores the records of users' stakes
    mapping(uint256 => StakeInfo) public stakes;
    // struccture that stores the records of users' staked tokens
    mapping(address => uint256[]) public stakedTokens;

    // Base reward that staker will receive for his stake
    uint256 public baseRewardPerSecond;

    event Stake(address indexed user, uint256 indexed tokenId);
    event Unstake(address indexed user, uint256 indexed tokenId);
    event Harvest(address indexed user, uint256 indexed tokenId, uint256 amount);

    /**
     * @dev the constructor arguments:
     * @param _nftlAddress address of token - the same used to pay rewards
     * @param _heroesAddress address of token - the same accepted for staking
     */
    function initialize(address _nftlAddress, address _heroesAddress) public initializer {
        require(_nftlAddress != address(0), "Empty NFTL token address");
        require(_heroesAddress != address(0), "Empty heroes address");
        nftlToken = IERC20(_nftlAddress);
        heroesToken = Collection(_heroesAddress);
        __Ownable_init();
    }

    /**
     * @dev start accepting new stakes. Called only by the owner
     */
    function start() public onlyOwner {
        require(!stakesOpen, "Stakes are open already");
        stakesOpen = true;
    }

    /**
     * @dev stop accepting new stakes. Called only by the owner
     */
    function stop() public onlyOwner {
        require(stakesOpen, "Stakes are stopped already");
        stakesOpen = false;
    }

    /**
     * @dev set base reward for tokens
     * @param _baseRewardPerSecond  base reward in second
     */

    function setBaseRewardPerSecond(uint256 _baseRewardPerSecond) public onlyOwner {
        baseRewardPerSecond = _baseRewardPerSecond;
    }

    /**
     * @dev the owner is able to withdraw excess tokens
     * @param _to  address who will receive the funds
     * @param _amount amount of tokens in atto (1e-18) units
     */

    function withdrawNftl(address _to, uint256 _amount) public onlyOwner {
        require(_to != address(0), "Empty receiver address");
        require(_amount > 0, "Zero amount");
        require(nftlToken.balanceOf(address(this)) >= _amount, "Not enough tokens");
        nftlToken.transfer(_to, _amount);
    }

    /**
     * @dev submit the stake
     * @param _tokenId id of hero token
     */
    function stake(uint256 _tokenId) external {
        require(stakesOpen, "stake: not open");
        stakes[_tokenId].staked = true;
        stakes[_tokenId].stakerAddress = msg.sender;
        stakes[_tokenId].lastUpdateTime = block.timestamp;

        // stakers get welcome bonus for their first stake
        if (stakes[_tokenId].totalYield == 0) {
            stakes[_tokenId].totalYield = WELCOME_BONUS_TIME * getTokenRewardPerSecond(_tokenId);
        }
        stakedTokens[msg.sender].push(_tokenId);
        emit Stake(msg.sender, _tokenId);
        heroesToken.safeTransferFrom(msg.sender, address(this), _tokenId);
    }

    /**
     * @dev withdraw the user's staked token
     * @param _tokenId id of hero token
     */
    function unstake(uint256 _tokenId) external {
        require(msg.sender == stakes[_tokenId].stakerAddress, "Sender is not staker");
        require(stakes[_tokenId].staked, "Unstaked already");
        _updateYield(_tokenId);
        stakes[_tokenId].staked = false;
        stakes[_tokenId].stakerAddress = address(0);

        // Since `delete` Solidity operator leaves zeroes at the deleted index and
        // doesn'd decrease array length.
        // To actually drop data and shorten the list, we copy last item to the index
        // of removed value (overwriting it) then pop last element to decrease array size
        for (uint256 i = 0; i < stakedTokens[msg.sender].length; ++i) {
            if (stakedTokens[msg.sender][i] == _tokenId) {
                uint256 lastElementIndex = stakedTokens[msg.sender].length - 1;
                stakedTokens[msg.sender][i] = stakedTokens[msg.sender][lastElementIndex];
                stakedTokens[msg.sender].pop();
                break;
            }
        }

        emit Unstake(msg.sender, _tokenId);
        _calculateAndTransferHarvest(_tokenId);
        heroesToken.safeTransferFrom(address(this), msg.sender, _tokenId);
    }

    /**
     * @dev harvest accumulated rewards. Can be called many times.
     * @param _tokenId   Id of the token to be harvested
     */
    function harvest(uint256 _tokenId) external {
        address currentTokenHolder = heroesToken.ownerOf(_tokenId);
        if (currentTokenHolder == address(this)) {
            // token is on staking contract, so we need to check it was indeed staked by msg.sender
            require(msg.sender == stakes[_tokenId].stakerAddress, "Sender is not staker");
            _updateYield(_tokenId);
        } else {
            // token is on another address, so we need to check msg.sender is its owner
            require(msg.sender == currentTokenHolder, "Sender is not holder");
        }

        require(stakes[_tokenId].totalYield > stakes[_tokenId].harvestedYield, "No harvestableYield");
        _calculateAndTransferHarvest(_tokenId);
    }

    /**
     * @dev return the array of staked token IDs
     * @param _staker address of token staker
     * @return stakedTokens array of staked token IDs
     */
    function getStakedTokens(address _staker) public view returns (uint256[] memory) {
        return stakedTokens[_staker];
    }

    /**
     * @dev return unaccounted reward that is not reflected in the contract state
     * for staked tokens this function returns value that increments each block.
     * For tokens that are not staked it returns 0
     * @param _tokenId index of the token
     * @return rewardSinceLastUpdate reward tokens that were accumulated sinceLastUpdate
     */
    function getRewardSinceLastUpdate(uint256 _tokenId) public view returns (uint256 rewardSinceLastUpdate) {
        rewardSinceLastUpdate = 0;
        if (stakes[_tokenId].staked) {
            uint256 secondsStaked = block.timestamp - stakes[_tokenId].lastUpdateTime;
            rewardSinceLastUpdate = getTokenRewardPerSecond(_tokenId) * secondsStaked;
        }
    }

    /**
     * @dev get the individual stake parameters of the user's staked token
     * @param _tokenId token stake index
     * @return staked the status of stake
     * @return stakerAddress address of staker
     * @return lastUpdateTime time of start staking
     * @return totalYield entire yield for the stake
     * @return harvestedYield The part of yield user harvested already
     */
    function getStake(uint256 _tokenId)
        external
        view
        returns (
            bool staked,
            address stakerAddress,
            uint256 lastUpdateTime,
            uint256 totalYield,
            uint256 harvestedYield
        )
    {
        StakeInfo memory _stake = stakes[_tokenId];
        staked = _stake.staked;
        stakerAddress = _stake.stakerAddress;
        lastUpdateTime = _stake.lastUpdateTime;
        totalYield = _stake.totalYield + getRewardSinceLastUpdate(_tokenId);
        harvestedYield = _stake.harvestedYield;
    }

    /**
     * @dev calculate reward speed for the given tokenId
     * @param _tokenId token id
     * @return rewardPerSecond in atto tokens per second
     */
    function getTokenRewardPerSecond(uint256 _tokenId) public view returns (uint256 rewardPerSecond) {
        rewardPerSecond = baseRewardPerSecond * heroesToken.getRarity(_tokenId);
    }

    /**
     * @dev Update accumulated reward for staked token
     * @param _tokenId token id
     */
    function _updateYield(uint256 _tokenId) internal {
        require(stakes[_tokenId].staked, "Token not staked");
        stakes[_tokenId].totalYield += getRewardSinceLastUpdate(_tokenId);
        stakes[_tokenId].lastUpdateTime = block.timestamp;
    }

    /**
     * @dev Calculate yield amount, emit Harvest event and pay nftl tokens
     * @param _tokenId token id
     */
    function _calculateAndTransferHarvest(uint256 _tokenId) internal {
        uint256 amount = stakes[_tokenId].totalYield - stakes[_tokenId].harvestedYield;
        stakes[_tokenId].harvestedYield = stakes[_tokenId].totalYield;
        emit Harvest(msg.sender, _tokenId, amount);
        nftlToken.transfer(msg.sender, amount);
    }
}