// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract ZubiToken {
    string public name = "ZoobiToken";
    string public symbol = "ZT92";
    uint8 public decimals = 18;
    uint256 public totalSupply = 1000000 * 10**uint256(decimals);
    
    mapping(address => uint256) public balanceOf;
    mapping(address => mapping(address => uint256)) public allowance;
    
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
    
    constructor() {
        balanceOf[msg.sender] = totalSupply;
    }
    
    function transfer(address to, uint256 value) public returns (bool success) {
        require(to != address(0), "Invalid address");
        require(balanceOf[msg.sender] >= value, "Insufficient balance");
        
        balanceOf[msg.sender] -= value;
        balanceOf[to] += value;
        
        emit Transfer(msg.sender, to, value);
        
        return true;
    }
    
    function approve(address spender, uint256 value) public returns (bool success) {
        allowance[msg.sender][spender] = value;
        
        emit Approval(msg.sender, spender, value);
        
        return true;
    }
    
    function transferFrom(address from, address to, uint256 value) public returns (bool success) {
        require(from != address(0), "Invalid sender address");
        require(to != address(0), "Invalid recipient address");
        require(balanceOf[from] >= value, "Insufficient balance");
        require(allowance[from][msg.sender] >= value, "Allowance exceeded");
        
        balanceOf[from] -= value;
        balanceOf[to] += value;
        allowance[from][msg.sender] -= value;
        
        emit Transfer(from, to, value);
        
        return true;
    }
}