BETH to ETH implementation

script/DeployBETHToETH.s.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.19;
+
+import "forge-std/Script.sol";
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import "src/hooks/cypher-eth/BETHToETH.sol";
+import {IWNativeToken} from "src/hooks/cypher-eth/IWNativeToken.sol";
+
+contract DeployBETHToETH is Script {
+    // mainnet addresses
+    address constant WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
+    address constant BETH = 0x5624344235607940d4d4EE76Bf8817d403EB9Cf8;
+    address constant swapRouter = 0x20C5893f69F635f55b0367C519F3f95e59c0b0Ab;
+
+    function run() external {
+        vm.startBroadcast();
+
+        BETHToETH bethToEth = new BETHToETH(IERC20(BETH), IWNativeToken(WETH), ISwapRouter(swapRouter));
+
+        console.log("BETHToETH deployed to:", address(bethToEth));
+        console.log("BETH address:", BETH);
+        console.log("WETH address:", WETH);
+
+        vm.stopBroadcast();
+    }
+}

src/hooks/cypher-eth/BETHToETH.sol

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+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.13;
+
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import {IWNativeToken} from "src/hooks/cypher-eth/IWNativeToken.sol";
+import {ISwapRouter} from "src/hooks/cypher-eth/ISwapRouter.sol";
+
+contract BETHToETH {
+    IERC20 public immutable bethContract;
+    IWNativeToken public immutable wethContract;
+    ISwapRouter public immutable swapRouterContract;
+
+    constructor(IERC20 _bethContract, IWNativeToken _wethContract, ISwapRouter _swapRouterContract) {
+        require(address(_bethContract) != address(0), "Invalid BETH address");
+        require(address(_wethContract) != address(0), "Invalid WETH address");
+        require(address(_swapRouterContract) != address(0), "Invalid WETH address");
+        bethContract = _bethContract;
+        wethContract = _wethContract;
+        swapRouterContract = _swapRouterContract;
+    }
+
+    function swapBethWithEth(uint256 _swapAmount, address _recipient) public returns (uint256 amountOut) {
+        require(_swapAmount > 0, "Amount must be greater than 0");
+        require(_recipient != address(0), "Invalid recipient");
+
+        require(
+            bethContract.transferFrom(msg.sender, address(this), _swapAmount), "error while transferFrom beth to this"
+        );
+
+        bethContract.approve(address(swapRouterContract), _swapAmount);
+
+        amountOut = swapRouterContract.exactInputSingle(
+            ISwapRouter.ExactInputSingleParams({
+                tokenIn: address(bethContract),
+                tokenOut: address(wethContract),
+                deployer: address(0),
+                recipient: address(this),
+                deadline: block.timestamp + 15 minutes,
+                amountIn: _swapAmount,
+                amountOutMinimum: 0,
+                limitSqrtPrice: 0
+            })
+        );
+
+        bethContract.approve(address(swapRouterContract), 0); // extra safety
+        wethContract.withdraw(amountOut);
+        (bool success,) = _recipient.call{value: amountOut}("");
+        require(success, "ETH transfer failed");
+    }
+
+    fallback() external payable {}
+}

src/hooks/cypher-eth/ISwapRouter.sol

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+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.13;
+
+interface ISwapRouter {
+    struct ExactInputSingleParams {
+        address tokenIn;
+        address tokenOut;
+        address deployer;
+        address recipient;
+        uint256 deadline;
+        uint256 amountIn;
+        uint256 amountOutMinimum;
+        uint160 limitSqrtPrice;
+    }
+
+    function exactInputSingle(ExactInputSingleParams calldata params) external payable returns (uint256 amountOut);
+}

src/hooks/cypher-eth/IWNativeToken.sol

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+// SPDX-License-Identifier: GPL-2.0-or-later
+pragma solidity ^0.8.0;
+
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+/// @title Interface for WNativeToken
+interface IWNativeToken is IERC20 {
+    /// @notice Deposit ether to get wrapped ether
+    function deposit() external payable;
+
+    /// @notice Withdraw wrapped ether to get ether
+    function withdraw(uint256) external;
+}