From b6a8ca344955515874211097dee2cee63ff4aa03 Mon Sep 17 00:00:00 2001
From: Denis Fadeev <denis@fadeev.org>
Date: Mon, 7 Oct 2024 20:28:19 +0300
Subject: [PATCH] switch to approve

---
 examples/hello/contracts/Hello.sol           | 10 ++++++----
 examples/hello/tasks/helloCall.ts            |  6 +-----
 examples/hello/tasks/helloWithdrawAndCall.ts |  8 ++++----
 3 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/examples/hello/contracts/Hello.sol b/examples/hello/contracts/Hello.sol
index 5546f8f0..afebf156 100644
--- a/examples/hello/contracts/Hello.sol
+++ b/examples/hello/contracts/Hello.sol
@@ -38,6 +38,7 @@ contract Hello is UniversalContract {
         RevertOptions memory revertOptions
     ) external {
         (, uint256 gasFee) = IZRC20(zrc20).withdrawGasFeeWithGasLimit(gasLimit);
+        IZRC20(zrc20).transferFrom(msg.sender, address(this), gasFee);
         IZRC20(zrc20).approve(address(gateway), gasFee);
         gateway.call(receiver, zrc20, message, gasLimit, revertOptions);
     }
@@ -52,10 +53,11 @@ contract Hello is UniversalContract {
     ) external {
         (address gasZRC20, uint256 gasFee) = IZRC20(zrc20)
             .withdrawGasFeeWithGasLimit(gasLimit);
-        if (zrc20 == gasZRC20) {
-            IZRC20(zrc20).approve(address(gateway), amount + gasFee);
-        } else {
-            IZRC20(zrc20).approve(address(gateway), amount);
+        uint256 total = zrc20 == gasZRC20 ? amount + gasFee : amount;
+        IZRC20(zrc20).transferFrom(msg.sender, address(this), total);
+        IZRC20(zrc20).approve(address(gateway), total);
+        if (zrc20 != gasZRC20) {
+            IZRC20(gasZRC20).transferFrom(msg.sender, address(this), gasFee);
             IZRC20(gasZRC20).approve(address(gateway), gasFee);
         }
         gateway.withdrawAndCall(
diff --git a/examples/hello/tasks/helloCall.ts b/examples/hello/tasks/helloCall.ts
index 92ca946a..ef977e98 100644
--- a/examples/hello/tasks/helloCall.ts
+++ b/examples/hello/tasks/helloCall.ts
@@ -58,11 +58,7 @@ const main = async (args: any, hre: HardhatRuntimeEnvironment) => {
   const gasLimit = hre.ethers.BigNumber.from(args.txOptionsGasLimit);
   const zrc20 = new ethers.Contract(args.zrc20, ZRC20ABI.abi, signer);
   const [, gasFee] = await zrc20.withdrawGasFeeWithGasLimit(gasLimit);
-  const zrc20TransferTx = await zrc20.transfer(
-    args.contract,
-    gasFee,
-    txOptions
-  );
+  const zrc20TransferTx = await zrc20.approve(args.contract, gasFee, txOptions);
 
   await zrc20TransferTx.wait();
 
diff --git a/examples/hello/tasks/helloWithdrawAndCall.ts b/examples/hello/tasks/helloWithdrawAndCall.ts
index b2799483..43818bd5 100644
--- a/examples/hello/tasks/helloWithdrawAndCall.ts
+++ b/examples/hello/tasks/helloWithdrawAndCall.ts
@@ -62,20 +62,20 @@ const main = async (args: any, hre: HardhatRuntimeEnvironment) => {
   const zrc20 = new ethers.Contract(args.zrc20, ZRC20ABI.abi, signer);
   const [gasZRC20, gasFee] = await zrc20.withdrawGasFeeWithGasLimit(gasLimit);
   const gasZRC20Contract = new ethers.Contract(gasZRC20, ZRC20ABI.abi, signer);
-  const gasFeeTransfer = await gasZRC20Contract.transfer(
+  const gasFeeApprove = await gasZRC20Contract.approve(
     args.contract,
     gasZRC20 == args.zrc20 ? gasFee.add(amount) : gasFee,
     txOptions
   );
-  await gasFeeTransfer.wait();
+  await gasFeeApprove.wait();
 
   if (gasZRC20 !== args.zrc20) {
-    const targetTokenTransfer = await zrc20.transfer(
+    const targetTokenApprove = await zrc20.approve(
       args.contract,
       gasFee.add(amount),
       txOptions
     );
-    await targetTokenTransfer.wait();
+    await targetTokenApprove.wait();
   }
 
   const factory = (await hre.ethers.getContractFactory(args.name)) as any;