token: return to sender

examples/nft/contracts/Connected.sol

@@ -115,14 +115,14 @@ contract Connected is
             address receiver,
             uint256 tokenId,
             string memory uri,
-            uint256 amount,
+            uint256 gasAmount,
             address sender
         ) = abi.decode(message, (address, uint256, string, uint256, address));
 
         _safeMint(receiver, tokenId);
         _setTokenURI(tokenId, uri);
-        if (amount > 0) {
-            (bool success, ) = sender.call{value: amount}("");
+        if (gasAmount > 0) {
+            (bool success, ) = sender.call{value: gasAmount}("");
             if (!success) revert GasTokenTransferFailed();
         }
         emit TokenTransferReceived(receiver, tokenId, uri);

examples/nft/contracts/Universal.sol

@@ -83,7 +83,13 @@ contract Universal is
             !IZRC20(destination).transferFrom(msg.sender, address(this), gasFee)
         ) revert TransferFailed();
         IZRC20(destination).approve(address(gateway), gasFee);
-        bytes memory message = abi.encode(receiver, tokenId, uri, 0);
+        bytes memory message = abi.encode(
+            receiver,
+            tokenId,
+            uri,
+            0,
+            msg.sender
+        );
 
         CallOptions memory callOptions = CallOptions(gasLimit, false);
 
@@ -125,7 +131,6 @@ contract Universal is
         uint256 amount,
         bytes calldata message
     ) external override onlyGateway {
-        revert("Method not implemented");
         if (context.sender != counterparty[zrc20]) revert Unauthorized();
 
         (
@@ -162,13 +167,8 @@ contract Universal is
                 CallOptions(gasLimit, false),
                 RevertOptions(address(0), false, address(0), "", 0)
             );
-            emit TokenTransferToDestination(
-                receiver,
-                destination,
-                tokenId,
-                uri
-            );
         }
+        emit TokenTransferToDestination(receiver, destination, tokenId, uri);
     }
 
     function onRevert(RevertContext calldata context) external onlyGateway {

examples/token/contracts/Connected.sol

@@ -15,6 +15,7 @@ contract Connected is ERC20, Ownable2Step, Events {
     error InvalidAddress();
     error Unauthorized();
     error InvalidGasLimit();
+    error GasTokenTransferFailed();
 
     modifier onlyGateway() {
         if (msg.sender != address(gateway)) revert Unauthorized();
@@ -51,7 +52,12 @@ contract Connected is ERC20, Ownable2Step, Events {
         if (receiver == address(0)) revert InvalidAddress();
         _burn(msg.sender, amount);
 
-        bytes memory message = abi.encode(destination, receiver, amount);
+        bytes memory message = abi.encode(
+            destination,
+            receiver,
+            amount,
+            msg.sender
+        );
         if (destination == address(0)) {
             gateway.call(
                 counterparty,
@@ -66,7 +72,7 @@ contract Connected is ERC20, Ownable2Step, Events {
                     address(this),
                     true,
                     address(0),
-                    abi.encode(receiver, amount),
+                    abi.encode(amount, msg.sender),
                     gasLimit
                 )
             );
@@ -80,22 +86,28 @@ contract Connected is ERC20, Ownable2Step, Events {
         bytes calldata message
     ) external payable onlyGateway returns (bytes4) {
         if (context.sender != counterparty) revert Unauthorized();
-        (address receiver, uint256 amount) = abi.decode(
-            message,
-            (address, uint256)
-        );
+        (
+            address receiver,
+            uint256 amount,
+            uint256 gasAmount,
+            address sender
+        ) = abi.decode(message, (address, uint256, uint256, address));
         _mint(receiver, amount);
+        if (gasAmount > 0) {
+            (bool success, ) = sender.call{value: amount}("");
+            if (!success) revert GasTokenTransferFailed();
+        }
         emit TokenTransferReceived(receiver, amount);
         return "";
     }
 
     function onRevert(RevertContext calldata context) external onlyGateway {
-        (address sender, uint256 amount) = abi.decode(
+        (uint256 amount, address receiver) = abi.decode(
             context.revertMessage,
-            (address, uint256)
+            (uint256, address)
         );
-        _mint(sender, amount);
-        emit TokenTransferReverted(sender, amount);
+        _mint(receiver, amount);
+        emit TokenTransferReverted(receiver, amount);
     }
 
     receive() external payable {}

examples/token/contracts/Universal.sol

@@ -69,7 +69,7 @@ contract Universal is ERC20, Ownable2Step, UniversalContract, Events {
             !IZRC20(destination).transferFrom(msg.sender, address(this), gasFee)
         ) revert TransferFailed();
         IZRC20(destination).approve(address(gateway), gasFee);
-        bytes memory message = abi.encode(receiver, amount);
+        bytes memory message = abi.encode(receiver, amount, 0, msg.sender);
 
         CallOptions memory callOptions = CallOptions(gasLimit, false);
 
@@ -103,26 +103,31 @@ contract Universal is ERC20, Ownable2Step, UniversalContract, Events {
     ) external override onlyGateway {
         if (keccak256(context.origin) != keccak256(counterparty[zrc20]))
             revert Unauthorized();
-        (address destination, address receiver, uint256 tokenAmount) = abi
-            .decode(message, (address, address, uint256));
+        (
+            address destination,
+            address receiver,
+            uint256 tokenAmount,
+            address sender
+        ) = abi.decode(message, (address, address, uint256, address));
         if (destination == address(0)) {
             _mint(receiver, tokenAmount);
         } else {
             (, uint256 gasFee) = IZRC20(destination).withdrawGasFeeWithGasLimit(
                 gasLimit
             );
-            SwapHelperLib.swapExactTokensForTokens(
+            uint256 out = SwapHelperLib.swapExactTokensForTokens(
                 uniswapRouter,
                 zrc20,
                 amount,
                 destination,
                 0
             );
-            IZRC20(destination).approve(address(gateway), gasFee);
-            gateway.call(
-                counterparty[destination],
+            IZRC20(destination).approve(address(gateway), out);
+            gateway.withdrawAndCall(
+                abi.encodePacked(counterparty[destination]),
+                out - gasFee,
                 destination,
-                abi.encode(receiver, tokenAmount),
+                abi.encode(receiver, tokenAmount, out - gasFee, sender),
                 CallOptions(gasLimit, false),
                 RevertOptions(address(0), false, address(0), "", 0)
             );