// File: lib/openzeppelin-contracts/contracts/access/Ownable.sol



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

pragma solidity ^0.8.0;

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

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

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

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

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

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

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

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

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

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

// File: lib/openzeppelin-contracts/contracts/security/ReentrancyGuard.sol



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

pragma solidity ^0.8.0;

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

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

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be _NOT_ENTERED
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

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

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

// File: lib/openzeppelin-contracts/contracts/token/ERC20/ERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;

import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * The default value of {decimals} is 18. To select a different value for
     * {decimals} you should overload it.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

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

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless this function is
     * overridden;
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `from` to `to`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     */
    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
            // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
            // decrementing then incrementing.
            _balances[to] += amount;
        }

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        unchecked {
            // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
            _balances[account] += amount;
        }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
            // Overflow not possible: amount <= accountBalance <= totalSupply.
            _totalSupply -= amount;
        }

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    function _spendAllowance(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens 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 amount
    ) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been 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 _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

// File: lib/openzeppelin-contracts/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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);

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

// File: lib/openzeppelin-contracts/contracts/token/ERC20/extensions/IERC20Metadata.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

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

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

// File: lib/openzeppelin-contracts/contracts/token/ERC721/IERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

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

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

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

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

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

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

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * 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;

    /**
     * @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 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: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC721
     * or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
     * understand this adds an external call which potentially creates a reentrancy vulnerability.
     *
     * 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 Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

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

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

// File: lib/openzeppelin-contracts/contracts/token/ERC721/IERC721Receiver.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (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 IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// File: lib/openzeppelin-contracts/contracts/utils/Context.sol



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

pragma solidity ^0.8.0;

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

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

// File: lib/openzeppelin-contracts/contracts/utils/introspection/IERC165.sol



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

pragma solidity ^0.8.0;

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

// File: src/ChillToken.sol



// SPDX-License-Identifier: MIT LICENSE
pragma solidity ^0.8.15;

/*
  /$$$$$$ /$$   /$$/$$$$$$/$$      /$$      /$$$$$$$ /$$$$$$/$$      /$$      
 /$$__  $| $$  | $|_  $$_| $$     | $$     | $$__  $|_  $$_| $$     | $$      
| $$  \__| $$  | $$ | $$ | $$     | $$     | $$  \ $$ | $$ | $$     | $$      
| $$     | $$$$$$$$ | $$ | $$     | $$     | $$$$$$$/ | $$ | $$     | $$      
| $$     | $$__  $$ | $$ | $$     | $$     | $$____/  | $$ | $$     | $$      
| $$    $| $$  | $$ | $$ | $$     | $$     | $$       | $$ | $$     | $$      
|  $$$$$$| $$  | $$/$$$$$| $$$$$$$| $$$$$$$| $$      /$$$$$| $$$$$$$| $$$$$$$$
 \______/|__/  |__|______|________|________|__/     |______|________|________/                                                                                                                                                                                                                               
*/

/// ============ Imports ============

import "openzeppelin-contracts/token/ERC20/ERC20.sol";

contract ChillToken is ERC20 {
    /// @notice address permissioned to mint new $CHILL tokens
    address public immutable minter;

    constructor(address _minter) ERC20("CHILL", "CHILL") {
        minter = _minter;
    }

    /// @notice only minter modifier
    modifier onlyMinter() {
        require(
            msg.sender == minter,
            "not authorized to mint new $CHILL tokens"
        );

        _;
    }

    /// @notice mints new $CHILL token
    function mint(address account, uint256 amount) external onlyMinter {
        _mint(account, amount);
    }
}

// File: src/ChillpillStaking.sol



// SPDX-License-Identifier: MIT LICENSE
pragma solidity ^0.8.15;

/*
  /$$$$$$ /$$   /$$/$$$$$$/$$      /$$      /$$$$$$$ /$$$$$$/$$      /$$      
 /$$__  $| $$  | $|_  $$_| $$     | $$     | $$__  $|_  $$_| $$     | $$      
| $$  \__| $$  | $$ | $$ | $$     | $$     | $$  \ $$ | $$ | $$     | $$      
| $$     | $$$$$$$$ | $$ | $$     | $$     | $$$$$$$/ | $$ | $$     | $$      
| $$     | $$__  $$ | $$ | $$     | $$     | $$____/  | $$ | $$     | $$      
| $$    $| $$  | $$ | $$ | $$     | $$     | $$       | $$ | $$     | $$      
|  $$$$$$| $$  | $$/$$$$$| $$$$$$$| $$$$$$$| $$      /$$$$$| $$$$$$$| $$$$$$$$
 \______/|__/  |__|______|________|________|__/     |______|________|________/                                                                                                                                                                                                                               
*/

/// ============ Imports ============

import "./ChillToken.sol";
import "./PartyPillStaking.sol";
import "openzeppelin-contracts/token/ERC721/IERC721.sol";
import "openzeppelin-contracts/token/ERC721/IERC721Receiver.sol";
import "openzeppelin-contracts/security/ReentrancyGuard.sol";

contract ChillpillStaking is
    PartyPillStaking,
    ReentrancyGuard,
    IERC721Receiver
{
    /// @notice total count of staked chillpill nfts
    uint256 public totalStaked;
    /// @notice $CHILL Token
    ChillToken public immutable chillToken;
    /// @notice max supply of $CHILL token
    uint256 public immutable maxSupply = 8080000000000000000000000;
    /// @notice returns amount of $CHILL earned by staking 1 pill for 1 day
    uint256 public dailyStakeRate;
    /// @notice number of $CHILL halvenings executed
    uint8 public halveningCount;

    // struct to store a stake's token, owner, and earning values
    struct Stake {
        uint24 tokenId;
        uint48 timestamp;
        address owner;
    }

    /// @notice event fired when NFT is staked
    event NFTStaked(address owner, uint256 tokenId, uint256 value);
    /// @notice event fired when NFT is unstaked
    event NFTUnstaked(address owner, uint256 tokenId, uint256 value);
    /// @notice event fired when $CHILL is claimed
    event Claimed(address owner, uint256 amount);

    /// @notice address of ChillRx ERC721 contract
    address public nftAddress;
    /// @notice amount of $CHILL claimed
    uint256 public totalClaimed;
    /// @notice total amount of ChillRx + PartyPills
    uint256 public totalNftSupply;

    // maps tokenId to stake
    mapping(uint256 => Stake) public vault;

    constructor(address _nft, uint256 _totalNftSupply) {
        chillToken = new ChillToken(address(this));
        nftAddress = _nft;
        totalNftSupply = _totalNftSupply;
        dailyStakeRate = 8080000000000000000;
    }

    /// @notice transfer pill to staking contract
    function _stakeTransfer(IERC721 _nft, uint256 _tokenId) private {
        require(_nft.ownerOf(_tokenId) == msg.sender, "not your token");
        require(
            _nft.isApprovedForAll(msg.sender, address(this)) ||
                _nft.getApproved(_tokenId) == address(this),
            "not approved for transfer"
        );
        _nft.safeTransferFrom(msg.sender, address(this), _tokenId);
    }

    /// @notice transfer pill from staking contract to owner
    function _unstakeTransfer(uint256 _tokenId, address _account) private {
        if (_tokenId > partyPillStartIndex) {
            IERC721(partyPillAddress).safeTransferFrom(
                address(this),
                _account,
                _tokenId - partyPillStartIndex
            );
        } else {
            IERC721(nftAddress).safeTransferFrom(
                address(this),
                _account,
                _tokenId
            );
        }
    }

    /// @notice stake you pills
    function stake(uint256[] calldata tokenIds) external nonReentrant {
        uint256 tokenId;
        totalStaked += tokenIds.length;
        IERC721 _nft = IERC721(nftAddress);
        IERC721 _partyPill = IERC721(partyPillAddress);
        for (uint256 i; i != tokenIds.length; i++) {
            tokenId = tokenIds[i];
            require(vault[tokenId].owner == address(0), "already staked");
            if (tokenIds[i] > partyPillStartIndex) {
                uint256 _tokenId = tokenId - partyPillStartIndex;
                _stakeTransfer(_partyPill, _tokenId);
            } else {
                _stakeTransfer(_nft, tokenIds[i]);
            }

            emit NFTStaked(msg.sender, tokenId, block.timestamp);

            vault[tokenId] = Stake({
                owner: msg.sender,
                tokenId: uint24(tokenId),
                timestamp: uint48(block.timestamp)
            });
        }
    }

    /// @notice cut distribution of $CHILL in half
    function halvening() internal {
        if (halveningCount < 3) {
            dailyStakeRate = dailyStakeRate / 2;
            ++halveningCount;
        }
    }

    /// @notice unstake pills
    function _unstakeMany(address account, uint256[] calldata tokenIds)
        internal
    {
        uint256 tokenId;
        totalStaked -= tokenIds.length;
        for (uint256 i; i != tokenIds.length; i++) {
            tokenId = tokenIds[i];
            Stake memory staked = vault[tokenId];
            require(staked.owner == msg.sender, "not an owner");

            delete vault[tokenId];
            emit NFTUnstaked(account, tokenId, block.timestamp);
            _unstakeTransfer(tokenId, account);
        }
    }

    /// @notice claim $CHILL for self
    function claim(uint256[] calldata tokenIds) external nonReentrant {
        _claim(msg.sender, tokenIds, false);
    }

    /// @notice claim $CHILL for target address
    function claimForAddress(address account, uint256[] calldata tokenIds)
        external
        nonReentrant
    {
        _claim(account, tokenIds, false);
    }

    /// @notice claim $CHILL and unstake Pill
    function unstake(uint256[] calldata tokenIds) external nonReentrant {
        _claim(msg.sender, tokenIds, true);
    }

    /// @notice claim $CHILL and unstake Pill (optional)
    function _claim(
        address account,
        uint256[] calldata tokenIds,
        bool _unstake
    ) internal {
        uint256 tokenId;
        uint256 earned = 0;

        for (uint256 i; i != tokenIds.length; i++) {
            tokenId = tokenIds[i];
            Stake memory staked = vault[tokenId];
            require(staked.owner == account, "not an owner");
            uint256 stakedAt = staked.timestamp;
            uint256 currentTime = block.timestamp;

            if (tokenId > partyPillStartIndex) {
                earned += calculateEarn(stakedAt) * partyPillMultiplier;
            } else {
                earned += calculateEarn(stakedAt);
            }

            vault[tokenId] = Stake({
                owner: account,
                tokenId: uint24(tokenId),
                timestamp: uint48(currentTime)
            });
        }
        if (earned > 0) {
            if (earned + chillToken.totalSupply() > maxSupply) {
                earned = maxSupply - chillToken.totalSupply();
            }
            chillToken.mint(account, earned);
            totalClaimed += earned;
        }
        if (chillToken.totalSupply() > maxSupply / (2 * (halveningCount + 1))) {
            halvening();
        }
        if (_unstake) {
            _unstakeMany(account, tokenIds);
        }
        emit Claimed(account, earned);
    }

    /// @notice returns amount of $CHILL earned by staking 1 pill for 1 second
    function secondStakeRate() public view returns (uint256) {
        return dailyStakeRate / 1 days + (dailyStakeRate % 1 days);
    }

    /// @notice calculate amount of unclaimed $CHILL
    function calculateEarn(uint256 stakedAt) internal view returns (uint256) {
        uint256 stakeDuration = block.timestamp - stakedAt;
        uint256 payout = stakeDuration * secondStakeRate();
        return payout;
    }

    /// @notice amount of unclaimed $CHILL
    function earningInfo(address account, uint256[] calldata tokenIds)
        external
        view
        returns (uint256)
    {
        uint256 tokenId;
        uint256 earned = 0;

        for (uint256 i; i != tokenIds.length; i++) {
            tokenId = tokenIds[i];
            Stake memory staked = vault[tokenId];
            require(staked.owner == account, "not an owner");
            uint256 stakedAt = staked.timestamp;
            if (tokenId > partyPillStartIndex) {
                earned += calculateEarn(stakedAt) * partyPillMultiplier;
            } else {
                earned += calculateEarn(stakedAt);
            }
        }
        return earned;
    }

    /// @notice get number of tokens staked in account
    /// @dev DecentSDK compatible
    function balanceOf(address account) external view returns (uint256) {
        uint256 balance = 0;

        for (uint256 i = 0; i <= totalNftSupply + 1; i++) {
            if (vault[i].owner == account) {
                balance++;
            }
        }
        return balance;
    }

    /// @notice return nft tokens staked of owner
    function tokensOfOwner(address account)
        external
        view
        returns (uint256[] memory ownerTokens)
    {
        uint256[] memory tmp = new uint256[](totalNftSupply);

        uint256 index = 0;
        for (uint256 tokenId = 0; tokenId <= totalNftSupply + 1; tokenId++) {
            if (vault[tokenId].owner == account) {
                tmp[index] = vault[tokenId].tokenId;
                index++;
            }
        }

        uint256[] memory tokens = new uint256[](index);
        for (uint256 i; i != index; i++) {
            tokens[i] = tmp[i];
        }

        return tokens;
    }

    /// @notice handles reciept of ERC721 tokens
    function onERC721Received(
        address,
        address,
        // address from,
        uint256,
        bytes calldata
    ) external pure override returns (bytes4) {
        // require(from == address(0x0), "Cannot send nfts to Vault directly");
        return IERC721Receiver.onERC721Received.selector;
    }

    /// @notice erc20Address for $CHILL token
    /// @dev DecentSDK compatibility
    function erc20Address() public view returns (address) {
        return address(chillToken);
    }

    /// @notice updates party pill information
    function updatePartyPill(
        address _partyPillAddress,
        uint8 _stakeMultiplier,
        uint256 _count
    ) public onlyOwner {
        totalNftSupply = totalNftSupply - partyPillCount + _count;
        _updatePartyPill(_partyPillAddress, _stakeMultiplier, _count);
    }

    // fallback
    fallback() external payable {}

    // receive eth
    receive() external payable {}
}

// File: src/PartyPillStaking.sol



// SPDX-License-Identifier: MIT LICENSE
pragma solidity ^0.8.15;

/*
  /$$$$$$ /$$   /$$/$$$$$$/$$      /$$      /$$$$$$$ /$$$$$$/$$      /$$      
 /$$__  $| $$  | $|_  $$_| $$     | $$     | $$__  $|_  $$_| $$     | $$      
| $$  \__| $$  | $$ | $$ | $$     | $$     | $$  \ $$ | $$ | $$     | $$      
| $$     | $$$$$$$$ | $$ | $$     | $$     | $$$$$$$/ | $$ | $$     | $$      
| $$     | $$__  $$ | $$ | $$     | $$     | $$____/  | $$ | $$     | $$      
| $$    $| $$  | $$ | $$ | $$     | $$     | $$       | $$ | $$     | $$      
|  $$$$$$| $$  | $$/$$$$$| $$$$$$$| $$$$$$$| $$      /$$$$$| $$$$$$$| $$$$$$$$
 \______/|__/  |__|______|________|________|__/     |______|________|________/                                                                                                                                                                                                                               
*/

/// ============ Imports ============
import "openzeppelin-contracts/access/Ownable.sol";

contract PartyPillStaking is Ownable {
    /// @notice party pill contract address
    address public partyPillAddress;
    /// @notice party pill staking multiplier
    uint8 public partyPillMultiplier;
    /// @notice number of party pills
    uint256 public partyPillCount;
    /// @notice token Id for start of Party Pills
    uint256 public immutable partyPillStartIndex = 10000;

    constructor() Ownable() {}

    /// @notice updates party pill information
    function _updatePartyPill(
        address _partyPillAddress,
        uint8 _stakeMultiplier,
        uint256 _count
    ) internal {
        partyPillAddress = _partyPillAddress;
        partyPillMultiplier = _stakeMultiplier;
        partyPillCount = _count;
    }
}