feat: add captcha contract

contracts/test/TestCaptcha.sol

@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity ^0.8.12;
+
+import "@openzeppelin/contracts/access/Ownable.sol";
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import "../samples/HybridAccount.sol";
+
+contract TestCaptcha is Ownable {
+    address payable immutable helperAddr;
+    uint256 constant public nativeFaucetAmount = 0.01 ether;
+    uint256 constant public waitingPeriod = 1 days;
+    IERC20 public token;
+
+    mapping(address => uint256) public claimRecords;
+
+    uint256 private constant SAFE_GAS_STIPEND = 6000;
+
+    constructor(address payable _helperAddr) {
+        helperAddr = _helperAddr;
+    }
+
+    event Withdraw(address receiver, uint256 nativeAmount);
+
+    receive() external payable {}
+
+    function withdraw(uint256 _nativeAmount) public onlyOwner {
+        (bool sent, ) = msg.sender.call{
+            gas: SAFE_GAS_STIPEND,
+            value: _nativeAmount
+        }("");
+        require(sent, "Failed to send native Ether");
+
+        emit Withdraw(msg.sender, _nativeAmount);
+    }
+
+    function verifycaptcha(
+        address _to,
+        bytes32 _uuid,
+        string memory _key
+    ) private returns (bool) {
+        HybridAccount ha = HybridAccount(helperAddr);
+
+        bytes memory req = abi.encodeWithSignature(
+            "verifyCaptcha(string,string,string)",
+             _to,
+            _uuid,
+            _key
+        );
+        bytes32 userKey = bytes32(abi.encode(msg.sender));
+        (uint32 error, bytes memory ret) = ha.CallOffchain(userKey, req);
+
+        if (error != 0) {
+            revert(string(ret));
+        }
+
+        bool isVerified;
+        (isVerified) = abi.decode(ret, (bool));
+        return isVerified;
+    }
+
+ function getTestnetETH(
+        bytes32 _uuid,
+        string memory _key,
+        address _to) external {
+        require(claimRecords[_to] + waitingPeriod <= block.timestamp, 'Invalid request');
+        require(verifyCaptcha(_to, _uuid, _key), "Invalid captcha");
+        claimRecords[_to] = block.timestamp;
+
+        (bool sent,) = (_to).call{gas: SAFE_GAS_STIPEND, value: nativeFaucetAmount}("");
+        require(sent, "Failed to send native");
+    }
+}