// SPDX-License-Identifier: MIT

pragma solidity ^0.8.15;
pragma abicoder v2;



/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 {
    
    /**
      * @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 Required interface of an ERC1155 compliant contract, as defined in the
 * https://eips.ethereum.org/EIPS/eip-1155[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155 {
   
    /**
     * @dev Transfers `amount` tokens of token type `id` from `from` to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - If the caller is not `from`, it must be have been approved to spend ``from``'s tokens via {setApprovalForAll}.
     * - `from` must have a balance of tokens of type `id` of at least `amount`.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function safeTransferFrom(address from, address to, uint256 id, uint256 amount, bytes calldata data) external;

}


/*
 * @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 GSN 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 payable) {
        return payable(msg.sender);
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}


/**
 * @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 () {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view 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 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");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}


/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract Pausable is Context {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    constructor () {
        _paused = false;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view returns (bool) {
        return _paused;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        require(!_paused, "Pausable: paused");
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        require(_paused, "Pausable: not paused");
        _;
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}


/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @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) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @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 sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

}


/**
* @dev AtomicSwap contract allows users to create many to many NFT swaps between two parties
* in a single atomic transaction. The contract supports the NFT ERC721 and ERC1155 standards 
* as well as the ability to send Ethereum as part of the contract. 
*/
contract AtomicSwap is Ownable, Pausable {

    using SafeMath for uint;

    // Swap Status
    enum swapStatus { New, Opened, Closed, Cancelled }
    enum contractType { ERC721, ERC1155 }

    struct atomicSwapContract {
        address payable addressOne;
        uint256 valueOne;
        address payable addressTwo;
        uint256 valueTwo;
        bytes nonce;
        nftStruct nftsOne;
        nftStruct nftsTwo;
    }

    struct nftStruct {
        address[] contractAddress;
        uint256[] tokenId; 
        uint256[] amount;
        bytes[] data;
        contractType[] typeOf;
    }

    mapping(bytes32 => swapStatus) public swapContract;  
    mapping(bytes32 => uint256) public _feePaid; 

    uint256 public _swapFee;
    uint256 public _pendingFee;
    uint256 public _feeBalance;
    address payable public _masterfu;

    event paymentReceived(address indexed payer, uint256 value);
    event swapCreated(bytes32 contractId);
    event swapClosed(bytes32 contractId);
    event swapCanceled(bytes32 contractId);
    event feeTransfer(uint256 amount);

    string public constant name = "Project Coin-fu Exchange";
    string public constant version = "1.0";
    string public constant codename = "Spock";

    constructor()  {

    }
 
    receive() external payable { 
        _feeBalance = _feeBalance.add(msg.value);
        emit paymentReceived(msg.sender, msg.value);
    }

    /** 
    * @dev Create the atomic swap contract & return the contractId
    */
    function createAtomicSwap(atomicSwapContract memory _contract) payable public whenNotPaused returns(bytes32) {
        require(msg.value >= _contract.valueOne.add(_swapFee), "coin-fu: not enough eth sent for this transaction");
        require(msg.sender == _contract.addressOne, "coin-fu: nft holder address does not match contract");
        // pending fee is refundable if the contract is cancelled
        _pendingFee = _pendingFee.add(_swapFee);
        // get a new contract id 
        bytes32 _contractId = getContractId(_contract);
        // swap fee paid for this contract
        _feePaid[_contractId] = _swapFee;
        // make sure this contract is new
        require(swapContract[_contractId] == swapStatus.New, "coin-fu: contract already exists");
        swapContract[_contractId] = swapStatus.Opened;
        emit swapCreated(_contractId);
        return _contractId;
    }

    /**
    * @dev internal function to calculate contract hash. Returns unique id per contract 
    */
    function getContractId(atomicSwapContract memory _contract) internal pure returns(bytes32) {
        return keccak256(abi.encode(_contract));
    }

    /**
    * @dev Close the atomic swap contract
    */
    function closeAtomicSwap(bytes32 _contractId, atomicSwapContract memory _contract) payable public whenNotPaused {
        require(msg.value >= _contract.valueTwo.add(_swapFee), "coin-fu: not enough eth sent for this transaction");
        require(_contractId == getContractId(_contract), "coin-fu: contract hash is not valid");
        require(msg.sender == _contract.addressTwo, "coin-fu: address does not match this contract");
        require(swapContract[_contractId] == swapStatus.Opened, "coin-fu: contract is no longer valid");
        
        // move the pending fee to contract fee balance
        _pendingFee = _pendingFee.sub(_feePaid[_contractId]);
        _feeBalance = _feeBalance.add(_swapFee.add(_feePaid[_contractId]));

        // do the eth transfers
        if (_contract.valueOne > 0) {
            _contract.addressTwo.transfer(_contract.valueOne);
        }
        if (_contract.valueTwo > 0) {
            _contract.addressOne.transfer(_contract.valueTwo);
        }
        // do the nft transfers 
        for(uint i=0; i < _contract.nftsTwo.contractAddress.length; i++) {
            if (_contract.nftsTwo.typeOf[i] == contractType.ERC721)
                IERC721(_contract.nftsTwo.contractAddress[i])
                .safeTransferFrom(_contract.addressTwo, 
                                  _contract.addressOne, 
                                  _contract.nftsTwo.tokenId[i],
                                  _contract.nftsTwo.data[i]);
            else
                IERC1155(_contract.nftsTwo.contractAddress[i])
                .safeTransferFrom(_contract.addressTwo, 
                                  _contract.addressOne, 
                                  _contract.nftsTwo.tokenId[i],
                                  _contract.nftsTwo.amount[i],
                                  _contract.nftsTwo.data[i]);
        }
        for(uint i=0; i < _contract.nftsOne.contractAddress.length; i++) {
             if (_contract.nftsOne.typeOf[i] == contractType.ERC721)
                IERC721(_contract.nftsOne.contractAddress[i])
                .safeTransferFrom(_contract.addressOne, 
                                  _contract.addressTwo, 
                                  _contract.nftsOne.tokenId[i],
                                  _contract.nftsOne.data[i]);
            else
                IERC1155(_contract.nftsOne.contractAddress[i])
                .safeTransferFrom(_contract.addressOne, 
                                  _contract.addressTwo, 
                                  _contract.nftsOne.tokenId[i],
                                  _contract.nftsOne.amount[i],
                                  _contract.nftsOne.data[i]);
        }
        swapContract[_contractId] = swapStatus.Closed;
        emit swapClosed(_contractId);
    }

    /**
     * @dev Cancel the atomic swap contract
     */ 
    function cancelAtomicSwap(bytes32 _contractId, atomicSwapContract memory _contract) public {
        require(_contractId == getContractId(_contract), "coin-fu: contract hash is not valid");
        require(msg.sender == _contract.addressOne, "coin-fu: invalid address - must be swap creator");
        require(swapContract[_contractId] == swapStatus.Opened, "coin-fu: contract is no longer open");
        // cancel the contract
        swapContract[_contractId] = swapStatus.Cancelled;
        // refund the fee paid 
        _pendingFee = _pendingFee.sub(_feePaid[_contractId]);
        // refund any crypto to swap creator - addressOne
        if(_contract.valueOne > 0){
            _contract.addressOne.transfer(_contract.valueOne.add(_feePaid[_contractId]));
        } else if (_feePaid[_contractId] > 0){
            _contract.addressOne.transfer(_feePaid[_contractId]);
        }
        emit swapCanceled(_contractId); 
    }

    /**
     * @dev Set the masterfu address for fee payouts 
     */
    function setMasterFu(address payable _address) public onlyOwner {
      require(_address != address(0), "coin-fu: zero address");
      _masterfu = _address;
    }

    /**
     * @dev Set the swap fee rate in wei
     */
    function setSwapFee(uint256 _fee) public onlyOwner {
      _swapFee = _fee;
    }

    /** 
     * @dev Returns the contract balance
     */
    function getContractBalance() public view returns (uint256) {
        return address(this).balance;
    }

    /**
     * @dev Admin function to widthdraw eth fees collected 
     */
    function transferFees(uint256 _amount) public returns(uint256) {
        require(msg.sender == _masterfu, "coin-fu: only master-fu can do this");
        require(_amount <= _feeBalance, "coin-fu: amount not available");
        _feeBalance = _feeBalance.sub(_amount);
        _masterfu.transfer(_amount);
        emit feeTransfer(_amount);
        return _amount;
    }

    /** 
     * @dev pause the contract
     */
    function pause(bool val) public onlyOwner {
        if (val) _pause();  else  _unpause();
    }

}