init hardhat

contracts/Lock.sol

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.9;
+
+// Uncomment this line to use console.log
+// import "hardhat/console.sol";
+
+contract Lock {
+    uint public unlockTime;
+    address payable public owner;
+
+    event Withdrawal(uint amount, uint when);
+
+    constructor(uint _unlockTime) payable {
+        require(
+            block.timestamp < _unlockTime,
+            "Unlock time should be in the future"
+        );
+
+        unlockTime = _unlockTime;
+        owner = payable(msg.sender);
+    }
+
+    function withdraw() public {
+        // Uncomment this line, and the import of "hardhat/console.sol", to print a log in your terminal
+        // console.log("Unlock time is %o and block timestamp is %o", unlockTime, block.timestamp);
+
+        require(block.timestamp >= unlockTime, "You can't withdraw yet");
+        require(msg.sender == owner, "You aren't the owner");
+
+        emit Withdrawal(address(this).balance, block.timestamp);
+
+        owner.transfer(address(this).balance);
+    }
+}