From 4139f340b997a1e778e78ccba91e2d791492cc2d Mon Sep 17 00:00:00 2001
From: Afolami Anuoluwapo <161776085+aabxtract@users.noreply.github.com>
Date: Wed, 14 Jan 2026 21:57:47 +0100
Subject: [PATCH] Add SimpleVault contract for ETH deposits and withdrawals

This contract allows users to deposit and withdraw ETH, with features for emergency withdrawals and pausing functionality.
---
 docs/base-chain/sample.sol | 126 +++++++++++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)
 create mode 100644 docs/base-chain/sample.sol

diff --git a/docs/base-chain/sample.sol b/docs/base-chain/sample.sol
new file mode 100644
index 00000000..dccb8a49
--- /dev/null
+++ b/docs/base-chain/sample.sol
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.20;
+
+/**
+ * @title SimpleVault
+ * @dev A basic vault contract for Base L2 that allows users to deposit and withdraw ETH
+ * @notice This demonstrates common patterns for Base L2 smart contracts
+ */
+contract SimpleVault {
+    // State variables
+    mapping(address => uint256) public balances;
+    uint256 public totalDeposits;
+    address public owner;
+    bool public isPaused;
+    
+    // Events
+    event Deposit(address indexed user, uint256 amount, uint256 timestamp);
+    event Withdrawal(address indexed user, uint256 amount, uint256 timestamp);
+    event EmergencyWithdraw(address indexed user, uint256 amount);
+    event PauseToggled(bool isPaused);
+    
+    // Modifiers
+    modifier onlyOwner() {
+        require(msg.sender == owner, "Not authorized");
+        _;
+    }
+    
+    modifier whenNotPaused() {
+        require(!isPaused, "Contract is paused");
+        _;
+    }
+    
+    // Constructor
+    constructor() {
+        owner = msg.sender;
+        isPaused = false;
+    }
+    
+    /**
+     * @dev Deposit ETH into the vault
+     * @notice Sends ETH to this function to deposit
+     */
+    function deposit() external payable whenNotPaused {
+        require(msg.value > 0, "Deposit must be greater than 0");
+        
+        balances[msg.sender] += msg.value;
+        totalDeposits += msg.value;
+        
+        emit Deposit(msg.sender, msg.value, block.timestamp);
+    }
+    
+    /**
+     * @dev Withdraw ETH from the vault
+     * @param amount The amount to withdraw in wei
+     */
+    function withdraw(uint256 amount) external whenNotPaused {
+        require(amount > 0, "Amount must be greater than 0");
+        require(balances[msg.sender] >= amount, "Insufficient balance");
+        require(address(this).balance >= amount, "Insufficient contract balance");
+        
+        balances[msg.sender] -= amount;
+        totalDeposits -= amount;
+        
+        (bool success, ) = msg.sender.call{value: amount}("");
+        require(success, "Transfer failed");
+        
+        emit Withdrawal(msg.sender, amount, block.timestamp);
+    }
+    
+    /**
+     * @dev Emergency withdraw - allows users to withdraw even when paused
+     */
+    function emergencyWithdraw() external {
+        uint256 balance = balances[msg.sender];
+        require(balance > 0, "No balance to withdraw");
+        
+        balances[msg.sender] = 0;
+        totalDeposits -= balance;
+        
+        (bool success, ) = msg.sender.call{value: balance}("");
+        require(success, "Transfer failed");
+        
+        emit EmergencyWithdraw(msg.sender, balance);
+    }
+    
+    /**
+     * @dev Get the balance of a specific user
+     * @param user The address to check
+     * @return The balance of the user
+     */
+    function getBalance(address user) external view returns (uint256) {
+        return balances[user];
+    }
+    
+    /**
+     * @dev Get the contract's total ETH balance
+     * @return The total ETH held by the contract
+     */
+    function getContractBalance() external view returns (uint256) {
+        return address(this).balance;
+    }
+    
+    /**
+     * @dev Toggle pause state (owner only)
+     */
+    function togglePause() external onlyOwner {
+        isPaused = !isPaused;
+        emit PauseToggled(isPaused);
+    }
+    
+    /**
+     * @dev Transfer ownership (owner only)
+     * @param newOwner The address of the new owner
+     */
+    function transferOwnership(address newOwner) external onlyOwner {
+        require(newOwner != address(0), "Invalid address");
+        owner = newOwner;
+    }
+    
+    // Fallback function to receive ETH
+    receive() external payable {
+        balances[msg.sender] += msg.value;
+        totalDeposits += msg.value;
+        emit Deposit(msg.sender, msg.value, block.timestamp);
+    }
+}