// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;


/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    function decimals() external view returns (uint8);
    /**
     * @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);
}


/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    // function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
    //     return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    // }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    // function functionDelegateCall(
    //     address target,
    //     bytes memory data,
    //     string memory errorMessage
    // ) internal returns (bytes memory) {
    //     require(isContract(target), "Address: delegate call to non-contract");

    //     (bool success, bytes memory returndata) = target.delegatecall(data);
    //     return verifyCallResult(success, returndata, errorMessage);
    // }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}


/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

//import "@openzeppelin/contracts/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;
    }
}
//import "@openzeppelin/contracts/access/Ownable.sol";
pragma solidity ^0.8.0;

//import "../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;
    }
}

/**
 * @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);
    }
}

contract PaydeceEscrow is  ReentrancyGuard , Ownable  {
    
    event EscrowDeposit(uint indexed orderId,Escrow escrow);
    event EscrowComplete(uint indexed orderId, Escrow escrow);
    event EscrowDisputeResolved(uint indexed orderId);
    event EscrowCancelResolved(uint indexed orderId);
    
    // address private _owner;
    // modifier onlyOwner() {
    //     require(_owner == msg.sender, "Ownable: caller is not the owner");
    //     _;
    // }

    enum EscrowStatus { Unknown, Funded, NOT_USED, Completed, Refund, Arbitration }

    uint256 public feeSeller;
    uint256 public feeBuyer;
    // uint256 public decimals;
    
     struct Escrow {
        address payable buyer;  //Comprador
        address payable seller; //Vendedor
        uint256 value;          //Monto compra
        uint256 sellerfee;      //Comision vendedor
        uint256 buyerfee;       //Comision comprador
        IERC20 currency;        //Moneda
        EscrowStatus status;    //Estado    
    }
    
    mapping(uint => Escrow) public escrows;
    
    using SafeERC20 for IERC20;
    
    //uint256 private feesAvailable;  // summation of fees that can be withdrawn
    mapping(IERC20 => uint) public feesAvailable;

    // IERC20 private tokenccy;
    
    constructor() {
        // _owner = msg.sender;
        //tokenccy = _currency;
        //feesAvailable = 0;
        feeSeller = 0; // 5%
        feeBuyer = 0; // 5%
        // decimals = 18; // digitos Stable
    }
    
   // Buyer defined as who buys usdt
    modifier onlyBuyer(uint _orderId){
        require(msg.sender == escrows[_orderId].buyer,"Only Buyer can call this");
        _;
    }

    // Seller defined as who sells usdt
    modifier onlySeller(uint _orderId) {
       require(msg.sender == escrows[_orderId].seller,"Only Seller can call this");
        _;
    }
    
   function getState(uint _orderId) public view returns (EscrowStatus){
        Escrow memory _escrow = escrows[_orderId];
        return _escrow.status;
    }

    // Seters getters
    function  setFeeSeller(uint256 _feeSeller) external onlyOwner{
        feeSeller = _feeSeller;
    }
    function  setFeeBuyer(uint256 _feeBuyer) external onlyOwner{
        feeBuyer = _feeBuyer;
    }
    // function  setDecimals(uint256 _decimals) external onlyOwner{
    //     decimals = _decimals;
    // }

    // Get the amount of transaction   
    function getValue(uint _orderId) public view returns (uint256){
        Escrow memory _escrow = escrows[_orderId];
        return _escrow.value;
    }
    
    // function getSellerFee(uint _orderId) public view returns (uint256){
    //     Escrow memory _escrow = escrows[_orderId];
    //     return _escrow.sellerfee;
    // }
    
    // function getBuyerFee(uint _orderId) public view returns (uint256){
    //     Escrow memory _escrow = escrows[_orderId];
    //     return _escrow.buyerfee;
    // }
    
    // function getAllowance(uint _orderId) public view returns (uint256){
    //     Escrow memory _escrow = escrows[_orderId];
    //     return tokenccy.allowance(_escrow.seller,address(this));
    // }
    
    // function getFeesAvailable() public virtual view onlyOwner returns (uint256){
    //     return feesAvailable;
    // }

    /* This is called by the server / contract owner */
    function createEscrow(uint _orderId, address payable _buyer, address payable _seller, uint256 _value,IERC20 _currency) external virtual   {
        require(escrows[_orderId].status == EscrowStatus.Unknown, "Escrow already exists");

        uint8 _decimals = _currency.decimals();
        //Obtiene el monto a transferir desde el comprador al contrato        
        uint256 _amountFeeBuyer = weiToEther(_value  * (feeBuyer * 10**_decimals) / (100 * 10**_decimals)); 
        
        //Valida el Allowance
        require( _currency.allowance( _buyer, address(this)) >= (_value+_amountFeeBuyer),"Seller approve to Escrow first");
    
        //TODO: validar la cantidad que envia el comprador, deberia ser el valor del asset + el buyerFee

        //Transfer USDT to contract
        _currency.safeTransferFrom(_buyer, address(this) , (_value+_amountFeeBuyer) );
                
        escrows[_orderId] = Escrow(_buyer, _seller, _value, feeSeller, feeBuyer, _currency,EscrowStatus.Funded);

        emit EscrowDeposit(_orderId, escrows[_orderId]);
    }

    function releaseEscrowOwner(uint _orderId) external onlyOwner {
        _releaseEscrow(_orderId);         
    }

    /* This is called by the buyer wallet */
    function releaseEscrow(uint _orderId) external onlyBuyer(_orderId) {
        _releaseEscrow(_orderId);         
    }

    function _releaseEscrow (uint _orderId) private nonReentrant{
        require(escrows[_orderId].status == EscrowStatus.Funded,"USDT has not been deposited");    

        uint8 _decimals = escrows[_orderId].currency.decimals();         
        
        //Obtiene el monto a transferir desde el comprador al contrato        
        uint256 _amountFeeBuyer = weiToEther(escrows[_orderId].value  * (feeBuyer * 10**_decimals) / (100 * 10**_decimals));
        uint256 _amountFeeSeller = weiToEther(escrows[_orderId].value  * (feeSeller * 10**_decimals) / (100 * 10**_decimals));

        //feesAvailable += _amountFeeBuyer + _amountFeeSeller;
        feesAvailable[escrows[_orderId].currency] += _amountFeeBuyer + _amountFeeSeller;

        // write as complete, in case transfer fails              
        escrows[_orderId].status = EscrowStatus.Completed;
        
        //Transfer to sellet Price Asset - FeeSeller
        escrows[_orderId].currency.safeTransfer( escrows[_orderId].seller, escrows[_orderId].value - _amountFeeSeller);   
        
        emit EscrowComplete(_orderId,  escrows[_orderId]);
        delete escrows[_orderId];        
    }
    
    
     /// release funds to the buyer - cancelled contract
    function refundBuyer(uint _orderId) external nonReentrant onlyOwner {       
        //require(escrows[_orderId].status == EscrowStatus.Refund,"Refund not approved");        
                
        // dont charge seller any fees - because its a refund
         
        escrows[_orderId].currency.safeTransfer(escrows[_orderId].buyer, escrows[_orderId].value);
        
        delete escrows[_orderId];
        emit EscrowDisputeResolved(_orderId);
    }

    /*
    Owner y Vendedor puede ejecucar esta funcion para retirar el dinero del contrato
    Devolver la plata al comprador cuando el contrato se cancela
    Devolver todo el dinero al comprador cuando el contrato se cancela
    */
    
    /* Cancela el Escrow y devuelve las stable al COMPRADOR */
    function cancelEscrow(uint _orderId) external nonReentrant onlyOwner{
        require(escrows[_orderId].status == EscrowStatus.Funded,"Refund not approved"); 

        escrows[_orderId].currency.safeTransfer(escrows[_orderId].buyer, escrows[_orderId].value);
        
        delete escrows[_orderId];
        emit EscrowCancelResolved(_orderId);
    }

    //TODO: Guardar los feets en array para despues poder hacer el retiro como Owner
    function withdrawFees(IERC20 _currency) external onlyOwner {        
        uint _amount;

        // This check also prevents underflow
        require(feesAvailable[_currency] <= 0 , "Amount > feesAvailable");

        _amount = _currency.balanceOf(owner()); 
                
        _currency.safeTransfer(owner(), _amount);
                
        feesAvailable[_currency] -= _amount;
    }

    function etherToWei(uint valueEther) private pure returns (uint)
    {
       return valueEther*(10**18);
    }
    function weiToEther(uint valueWei) private pure returns (uint)
    {
       return valueWei/(10**18);
    }

    function version() external virtual pure returns (string memory) {
        return "2.0.0";
    }
}