// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract AirodToken {
    string public name = "Airod";
    string public symbol = "AIROD";
    uint256 public totalSupply = 9.1e8 * 10 ** 18; // 9.1 billion tokens with 18 decimals
    uint8 public decimals = 18;

    mapping(address => uint256) public balanceOf;
    mapping(address => mapping(address => uint256)) public allowance;

    address public owner;

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);

    modifier onlyOwner() {
        require(msg.sender == owner, "Only owner can call this function.");
        _;
    }

    constructor() {
        owner = msg.sender;
        balanceOf[owner] = totalSupply;
    }

    function transfer(address to, uint256 value) external returns (bool) {
        require(to != address(0), "Invalid address.");
        require(value > 0 && value <= balanceOf[msg.sender], "Insufficient balance.");

        balanceOf[msg.sender] -= value;
        balanceOf[to] += value;
        emit Transfer(msg.sender, to, value);
        return true;
    }

    function approve(address spender, uint256 value) external returns (bool) {
        allowance[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);
        return true;
    }

    function transferFrom(address from, address to, uint256 value) external returns (bool) {
        require(from != address(0), "Invalid address.");
        require(to != address(0), "Invalid address.");
        require(value > 0 && value <= balanceOf[from], "Insufficient balance.");
        require(value <= allowance[from][msg.sender], "Insufficient allowance.");

        balanceOf[from] -= value;
        balanceOf[to] += value;
        allowance[from][msg.sender] -= value;
        emit Transfer(from, to, value);
        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue) external returns (bool) {
        uint256 newAllowance = allowance[msg.sender][spender] + addedValue;
        allowance[msg.sender][spender] = newAllowance;
        emit Approval(msg.sender, spender, newAllowance);
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) external returns (bool) {
        uint256 currentAllowance = allowance[msg.sender][spender];
        require(subtractedValue <= currentAllowance, "Decreased allowance below zero.");
        
        uint256 newAllowance = currentAllowance - subtractedValue;
        allowance[msg.sender][spender] = newAllowance;
        emit Approval(msg.sender, spender, newAllowance);
        return true;
    }

    function transferOwnership(address newOwner) external onlyOwner {
        require(newOwner != address(0), "Invalid address.");
        owner = newOwner;
    }

    function renounceOwnership() external onlyOwner {
        owner = address(0);
    }

    // Prevents accidental sending of ETH to the contract
    receive() external payable {
        revert("Contract does not accept ETH.");
    }
}

{
  "compilationTarget": {
    "AirodToken.sol": "AirodToken"
  },
  "evmVersion": "cancun",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "remappings": []
}