WETH Proxy

contracts/DePayWETHExchangeV1.sol

@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: BUSL-1.1
+
+pragma solidity 0.8.18;
+
+import './interfaces/IWETH.sol';
+
+/// @title DePayWETHExchangeV1
+/// @notice This contract limits access to WETH to the functions wrap & unwrap only.
+contract DePayWETHExchangeV1 {
+
+  /// @notice Address of WETH
+  IWETH public immutable WETH;
+
+  /// @dev Initializes the contract with WETH address.
+  /// @param _WETH The address of the WETH contract.
+  constructor (address _WETH) {
+    WETH = IWETH(_WETH);
+  }
+
+  /// @notice Accepts NATIVE transfers, required for unwrapping.
+  receive() external payable {}
+
+  /// @notice Deposits native currency and wraps it into WETH.
+  /// @dev Wraps sent value into WETH and transfers it back to the sender.
+  /// @return success Status of the deposit operation.
+  function deposit() external payable returns(bool){
+    WETH.deposit{value: msg.value}();
+    (bool success) = WETH.transfer(msg.sender, msg.value);
+    return success;
+  }
+
+  /// @notice Withdraws specified amount of WETH and unwraps it into native currency.
+  /// @dev Unwraps WETH into native currency and sends it back to the sender.
+  /// @param wad Amount of WETH to withdraw.
+  /// @return success Status of the withdrawal operation.
+  function withdraw(
+    uint wad
+  ) external returns(bool){
+    WETH.withdraw(wad);
+    (bool success,) = msg.sender.call{value: wad}(new bytes(0));
+    return success;
+  }
+}

contracts/interfaces/IWETH.sol

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity 0.8.18;
+
+interface IWETH {
+
+  function deposit() payable external;
+  function transfer(address dst, uint wad) external returns (bool);
+  function withdraw(uint wad) external;
+}

flatten/DePayWETHExchangeV1.sol

@@ -0,0 +1,58 @@
+// Dependency file: contracts/interfaces/IWETH.sol
+
+// SPDX-License-Identifier: MIT
+
+// pragma solidity 0.8.18;
+
+interface IWETH {
+
+  function deposit() payable external;
+  function transfer(address dst, uint wad) external returns (bool);
+  function withdraw(uint wad) external;
+}
+
+
+// Root file: contracts/DePayWETHExchangeV1.sol
+
+
+pragma solidity 0.8.18;
+
+// import 'contracts/interfaces/IWETH.sol';
+
+/// @title DePayWETHExchangeV1
+/// @notice This contract limits access to WETH to the functions wrap & unwrap only.
+contract DePayWETHExchangeV1 {
+
+  /// @notice Address of WETH
+  IWETH public immutable WETH;
+
+  /// @dev Initializes the contract with WETH address.
+  /// @param _WETH The address of the WETH contract.
+  constructor (address _WETH) {
+    WETH = IWETH(_WETH);
+  }
+
+  /// @notice Accepts NATIVE transfers, required for unwrapping.
+  receive() external payable {}
+
+  /// @notice Deposits native currency and wraps it into WETH.
+  /// @dev Wraps sent value into WETH and transfers it back to the sender.
+  /// @return success Status of the deposit operation.
+  function deposit() external payable returns(bool){
+    WETH.deposit{value: msg.value}();
+    (bool success) = WETH.transfer(msg.sender, msg.value);
+    return success;
+  }
+
+  /// @notice Withdraws specified amount of WETH and unwraps it into native currency.
+  /// @dev Unwraps WETH into native currency and sends it back to the sender.
+  /// @param wad Amount of WETH to withdraw.
+  /// @return success Status of the withdrawal operation.
+  function withdraw(
+    uint wad
+  ) external returns(bool){
+    WETH.withdraw(wad);
+    (bool success,) = msg.sender.call{value: wad}(new bytes(0));
+    return success;
+  }
+}

flatten/IWETH.sol

@@ -0,0 +1,12 @@
+// Root file: contracts/interfaces/IWETH.sol
+
+// SPDX-License-Identifier: MIT
+
+pragma solidity 0.8.18;
+
+interface IWETH {
+
+  function deposit() payable external;
+  function transfer(address dst, uint wad) external returns (bool);
+  function withdraw(uint wad) external;
+}

test/_pay-with-wrapped-conversion.ts

@@ -21,6 +21,7 @@ export default ({ blockchain })=>{
       let router
       let deadline
       let wrapperContract
+      let exchange
 
       beforeEach(async ()=>{
         wallets = await ethers.getSigners()
@@ -32,16 +33,21 @@ export default ({ blockchain })=>{
         router = await deploy()
       })
 
-      it('approves WRAPPER contract as exchange to convert payments', async ()=> {
-        await router.connect(wallets[0]).enable(WRAPPED, true)
+      it('deploys WETHExchange successfully', async ()=> {
+        const DePayWETHExchange = await ethers.getContractFactory('DePayWETHExchangeV1')
+        exchange = await DePayWETHExchange.deploy(wrapperContract.address)
+      })
+
+      it('approves DePayWETHExchange contract as exchange to convert payments', async ()=> {
+        await router.connect(wallets[0]).enable(exchange.address, true)
       })
 
       it('wraps NATIVE to WRAPPED and pays out WRAPPED', async ()=>{
         const amountIn = 1000000000
         const paymentAmount = 900000000
         const feeAmount = 100000000
 
-        const callData = wrapperContract.interface.encodeFunctionData("deposit", [])
+        const callData = exchange.interface.encodeFunctionData("deposit", [])
 
         const paymentReceiverBalanceBefore = await wrapperContract.balanceOf(wallets[1].address)
         const feeReceiverBalanceBefore = await wrapperContract.balanceOf(wallets[2].address)
@@ -51,7 +57,7 @@ export default ({ blockchain })=>{
           paymentAmount: paymentAmount,
           feeAmount: feeAmount,
           tokenInAddress: NATIVE,
-          exchangeAddress: WRAPPED,
+          exchangeAddress: exchange.address,
           tokenOutAddress: WRAPPED,
           paymentReceiverAddress: wallets[1].address,
           feeReceiverAddress: wallets[2].address,
@@ -75,7 +81,7 @@ export default ({ blockchain })=>{
         const paymentAmount = 900000000
         const feeAmount = 100000000
 
-        const callData = wrapperContract.interface.encodeFunctionData("withdraw", [amountIn])
+        const callData = exchange.interface.encodeFunctionData("withdraw", [amountIn])
 
         const paymentReceiverBalanceBefore = await provider.getBalance(wallets[1].address)
         const feeReceiverBalanceBefore = await provider.getBalance(wallets[2].address)
@@ -88,11 +94,11 @@ export default ({ blockchain })=>{
           paymentAmount: paymentAmount,
           feeAmount: feeAmount,
           tokenInAddress: WRAPPED,
-          exchangeAddress: WRAPPED,
+          exchangeAddress: exchange.address,
           tokenOutAddress: NATIVE,
           paymentReceiverAddress: wallets[1].address,
           feeReceiverAddress: wallets[2].address,
-          exchangeType: 0,
+          exchangeType: 2,
           receiverType: 0,
           exchangeCallData: callData,
           receiverCallData: ZERO,