feat: FrxEthRewarder

src/contracts/FrxEthRewarder.sol

@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+pragma solidity ^0.8.20;
+
+import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
+import { ReentrancyGuard } from "@openzeppelin/contracts/security/ReentrancyGuard.sol";
+import { Address } from "@openzeppelin/contracts/utils/Address.sol";
+
+contract FrxEthRewarder is Ownable, ReentrancyGuard {
+    uint256 public rewardAmount;
+    address public bot;
+    mapping(address user => bool yes) public rewarded;
+
+    event RewardBridger(address bridger, uint256 amount);
+
+    constructor() Ownable(msg.sender) {}
+
+    // -----------------------------------------------------------------------
+    //                               ONLY-BOT
+    // -----------------------------------------------------------------------
+
+    /// @notice reward bridgers a fixed amount of frxETH
+    /// @notice On duplicates, the loop continues to the next address to prevent halts
+    function rewardBridgers(address[] memory bridgers) external nonReentrant {
+        require(msg.sender == bot);
+
+        uint256 length = bridgers.length;
+        uint256 rewardAmount_ = rewardAmount;
+        for (uint256 i = 0; i < length; ) {
+            address bridger = bridgers[i];
+            if (!rewarded[bridger]) {
+                rewarded[bridger] = true;
+                // Do nothing if the recipient is a contract - to only reward EOA
+                if (bridger.code.length != 0) continue;
+                // Assume the call is a success
+                payable(bridger).call{ value: rewardAmount_ }("");
+
+                emit RewardBridger(bridger, rewardAmount_);
+            }
+
+            unchecked {
+                ++i;
+            }
+        }
+    }
+
+    // -----------------------------------------------------------------------
+    //                              ONLY-OWNER
+    // -----------------------------------------------------------------------
+
+    function setRewardAmount(uint256 _newRewardAmount) external onlyOwner {
+        rewardAmount = _newRewardAmount;
+    }
+
+    function setBot(address _newBot) external onlyOwner {
+        bot = _newBot;
+    }
+
+    function withdrawFrxEth(address recipient, uint256 amount) onlyOwner {
+        (bool success, ) = payable(recipient).call{ value: amount }("");
+        require(success, "ETH Transfer failed");
+    }
+}