// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)



/**
 * @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);
}


// OpenZeppelin Contracts v4.4.1 (utils/Context.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 Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;
}



// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}


// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}



contract MncStakeContract is Ownable {

    event Staked(address owner, uint256 tokenId, uint256 timestamp);
    event Unstaked(address owner, uint256 tokenId, uint256 timestamp);


    struct Stake {
        uint256 tokenId;
        uint256 timestamp;
    }

    IERC721 private mncNftContract;

    mapping(address => Stake[]) public stakes;

    bool public isPaused = false;
    uint256 public stakingPeriod = 90;

    constructor() {
        mncNftContract = IERC721(0x3C044935B01d0cF9E157ef9A64c512e51dB5dFaf);
    }

    function onERC721Received(
        address,
        address,
        uint256,
        bytes calldata
    ) external pure returns (bytes4) {
        return bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"));
    }

    function stake(uint256[] memory _tokens) external {
        require(!isPaused, "Staking is paused.");
        require(mncNftContract.balanceOf(msg.sender) >= _tokens.length, "You don't have enough NFTs");

        uint256 timestamp = block.timestamp;

        for (uint256 i = 0; i < _tokens.length; i++) {
            mncNftContract.safeTransferFrom(msg.sender, address(this), _tokens[i]);
            stakes[msg.sender].push(Stake(_tokens[i], timestamp));
            emit Staked(msg.sender, _tokens[i], timestamp);
        }

    }


    function unstake(uint256[] memory _tokenIds) external {
        uint256 senderStakes = stakes[msg.sender].length;

        require(senderStakes > 0, "Address has no stakes.");

        for (uint256 tokenIdsIndex = 0; tokenIdsIndex < _tokenIds.length; tokenIdsIndex++) {
            uint256 _tokenId = _tokenIds[tokenIdsIndex];
            for (uint256 i = 0; i < senderStakes; i++) {
                if (stakes[msg.sender][i].tokenId == _tokenId && stakes[msg.sender][i].timestamp != 0) {
                    uint256 elapsedMins = (block.timestamp - stakes[msg.sender][i].timestamp) / 60;
                    uint256 elapsedDays = elapsedMins / 1440;
                    require(elapsedDays >= stakingPeriod, "Can not unstake before stakingPeriod.");
                    mncNftContract.safeTransferFrom(address(this), msg.sender, _tokenId);

                    //remove staked nft from stake list
                    stakes[msg.sender][i] = stakes[msg.sender][stakes[msg.sender].length - 1];
                    stakes[msg.sender].pop();
                    emit Unstaked(msg.sender, _tokenId, block.timestamp);

                    break;
                }
                if (i == senderStakes - 1) {
                    revert("Provided token id not staked.");
                }
            }
        }
    }

    function ownerStake(address userAddress, uint256 _tokenId) external onlyOwner {
        require(!isPaused, "Staking is paused.");
        uint256 timestamp = block.timestamp;
        mncNftContract.safeTransferFrom(msg.sender, address(this), _tokenId);
        stakes[userAddress].push(Stake(_tokenId, timestamp));
        emit Staked(userAddress, _tokenId, timestamp);
    }


    function getStakes(address _address) external view returns (Stake[] memory) {
        uint256 addressStakes = stakes[_address].length;

        require(addressStakes > 0, "Address has no stakes.");

        Stake[] memory res = new Stake[](addressStakes);

        for (uint256 i = 0; i < addressStakes; i++) {
            if (stakes[_address][i].timestamp != 0) {
                res[i] = Stake(stakes[_address][i].tokenId, stakes[_address][i].timestamp);
            }
        }

        return res;
    }

    function getStakesCount(address _address) public view returns(uint) {
        return stakes[_address].length;
    }

    function getStake(address _address, uint256 index) public view returns(uint256, uint256) {
        Stake storage addressStake = stakes[_address][index];
        return (addressStake.tokenId, addressStake.timestamp);
    }

    function togglePause(bool _state) external onlyOwner {
        isPaused = _state;
    }

    function setStakingPeriod(uint256 _stakingPeriod) external onlyOwner {
        stakingPeriod = _stakingPeriod;
    }

}