Refactor the Swap example to swap arbitrary ERC-20 and swap from EVM to Bitcoin (#85)

Author: fadeev

omnichain/swap/contracts/Swap.sol

@@ -30,47 +30,42 @@ contract Swap is zContract {
         uint256 amount,
         bytes calldata message
     ) external virtual override onlySystem {
-        uint32 targetChainID;
-        address recipient;
-        uint256 minAmountOut;
+        address targetTokenAddress;
+        bytes memory recipientAddress;
 
         if (context.chainID == BITCOIN) {
-            targetChainID = BytesHelperLib.bytesToUint32(message, 0);
-            recipient = BytesHelperLib.bytesToAddress(message, 4);
+            targetTokenAddress = BytesHelperLib.bytesToAddress(message, 0);
+            recipientAddress = abi.encodePacked(
+                BytesHelperLib.bytesToAddress(message, 20)
+            );
         } else {
-            (
-                uint32 targetChainID_,
-                address recipient_,
-                uint256 minAmountOut_
-            ) = abi.decode(message, (uint32, address, uint256));
-            targetChainID = targetChainID_;
-            recipient = recipient_;
-            minAmountOut = minAmountOut_;
+            (address targetToken, bytes memory recipient) = abi.decode(
+                message,
+                (address, bytes)
+            );
+            targetTokenAddress = targetToken;
+            recipientAddress = recipient;
         }
 
-        address targetZRC20 = systemContract.gasCoinZRC20ByChainId(
-            targetChainID
-        );
-
         uint256 outputAmount = SwapHelperLib._doSwap(
             systemContract.wZetaContractAddress(),
             systemContract.uniswapv2FactoryAddress(),
             systemContract.uniswapv2Router02Address(),
             zrc20,
             amount,
-            targetZRC20,
-            minAmountOut
+            targetTokenAddress,
+            0
         );
 
-        (address gasZRC20, uint256 gasFee) = IZRC20(targetZRC20)
+        (address gasZRC20, uint256 gasFee) = IZRC20(targetTokenAddress)
             .withdrawGasFee();
 
-        if (gasZRC20 != targetZRC20) revert WrongGasContract();
+        if (gasZRC20 != targetTokenAddress) revert WrongGasContract();
         if (gasFee >= outputAmount) revert NotEnoughToPayGasFee();
 
-        IZRC20(targetZRC20).approve(targetZRC20, gasFee);
-        IZRC20(targetZRC20).withdraw(
-            abi.encodePacked(recipient),
+        IZRC20(targetTokenAddress).approve(targetTokenAddress, gasFee);
+        IZRC20(targetTokenAddress).withdraw(
+            recipientAddress,
             outputAmount - gasFee
         );
     }

omnichain/swap/package.json

@@ -26,7 +26,7 @@
     "@types/node": ">=12.0.0",
     "@typescript-eslint/eslint-plugin": "^5.59.9",
     "@typescript-eslint/parser": "^5.59.9",
-    "@zetachain/toolkit": "^3.0.0",
+    "@zetachain/toolkit": "^4.0.0",
     "axios": "^1.3.6",
     "chai": "^4.2.0",
     "dotenv": "^16.0.3",
@@ -48,4 +48,4 @@
     "typechain": "^8.1.0",
     "typescript": ">=4.5.0"
   }
-}
+}

omnichain/swap/tasks/deploy.ts

@@ -34,4 +34,7 @@ const main = async (args: any, hre: HardhatRuntimeEnvironment) => {
   }
 };
 
-task("deploy", "Deploy the contract", main).addFlag("json", "Output in JSON");
+task("deploy", "Deploy the contract", main).addFlag(
+  "json",
+  "Output in JSON"
+);

omnichain/swap/tasks/interact.ts

@@ -3,21 +3,28 @@ import { HardhatRuntimeEnvironment } from "hardhat/types";
 import { parseEther } from "@ethersproject/units";
 import { getAddress } from "@zetachain/protocol-contracts";
 import { prepareData } from "@zetachain/toolkit/helpers";
-import { BigNumber } from "@ethersproject/bignumber";
+import bech32 from "bech32";
+import { utils } from "ethers";
 
 const main = async (args: any, hre: HardhatRuntimeEnvironment) => {
   const [signer] = await hre.ethers.getSigners();
 
-  const targetChainID = hre.config.networks[args.destination]?.chainId;
-  if (targetChainID === undefined) {
-    throw new Error("Invalid destination network");
+  let recipient;
+  try {
+    if (bech32.decode(args.recipient)) {
+      recipient = utils.solidityPack(
+        ["bytes"],
+        [utils.toUtf8Bytes(args.recipient)]
+      );
+    }
+  } catch (e) {
+    recipient = args.recipient;
   }
-  const minAmountOut = BigNumber.from("0");
 
   const data = prepareData(
     args.contract,
-    ["uint32", "address", "uint256"],
-    [targetChainID, args.recipient, minAmountOut]
+    ["address", "bytes"],
+    [args.targetToken, recipient]
   );
   const to = getAddress("tss", hre.network.name);
   const value = parseEther(args.amount);
@@ -30,14 +37,14 @@ const main = async (args: any, hre: HardhatRuntimeEnvironment) => {
     console.log(`🔑 Using account: ${signer.address}\n`);
 
     console.log(`🚀 Successfully broadcasted a token transfer transaction on ${hre.network.name} network.
-📝 Transaction hash: ${tx.hash}
-`);
+  📝 Transaction hash: ${tx.hash}
+  `);
   }
 };
 
 task("interact", "Interact with the contract", main)
   .addParam("contract", "The address of the withdraw contract on ZetaChain")
   .addParam("amount", "Amount of tokens to send")
-  .addParam("recipient")
   .addFlag("json", "Output in JSON")
-  .addParam("destination");
+  .addParam("targetToken")
+  .addParam("recipient");