// File: contracts/YOGA.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract YOGA {
    string public constant name = "YOGA";
    string public constant symbol = "YOGA";
    uint8 public constant decimals = 9;
    uint256 public totalSupply = 1000000000 * (10 ** uint256(decimals));

    mapping(address => uint256) public balances;
    mapping(address => mapping(address => uint256)) public allowed;

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);

    constructor() {
        balances[msg.sender] = totalSupply;
        emit Transfer(address(0), msg.sender, totalSupply);
    }

    function balanceOf(address _owner) public view returns (uint256) {
        return balances[_owner];
    }

    function transfer(address _to, uint256 _value) public returns (bool) {
        require(_to != address(0), "Invalid address");
        require(_value > 0, "Invalid amount");
        require(balances[msg.sender] >= _value, "Insufficient balance");

        balances[msg.sender] -= _value;
        balances[_to] += _value;
        emit Transfer(msg.sender, _to, _value);
        return true;
    }

    function approve(address _spender, uint256 _value) public returns (bool) {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    function allowance(address _owner, address _spender) public view returns (uint256) {
        return allowed[_owner][_spender];
    }

    function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
        require(_to != address(0), "Invalid address");
        require(_value > 0, "Invalid amount");
        require(_value <= balances[_from], "Insufficient balance");
        require(_value <= allowed[_from][msg.sender], "Allowance exceeded");

        balances[_from] -= _value;
        balances[_to] += _value;
        allowed[_from][msg.sender] -= _value;
        emit Transfer(_from, _to, _value);
        return true;
    }
}