// SPDX-License-Identifier: MIT
pragma solidity ^0.8.22;

library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        uint256 c = a - b;
        return c;
    }

    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: division by zero");
        uint256 c = a / b;
        return c;
    }
}

contract IronCladCrypto{
    using SafeMath for uint256;

    string public constant name = "Ironclad Crypto";
    string public constant symbol = "IC";
    uint8 public constant decimals = 18;  // 18 decimals to support fractional units

    uint256 public constant totalSupply = 3155760000 * (10 ** uint256(decimals));  // Total supply representing 100 years in seconds

    mapping(address => uint256) private balances;
    mapping(address => mapping(address => uint256)) private 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;
    }

    function balanceOf(address owner) public view returns (uint256) {
        return balances[owner];
    }

    function transfer(address to, uint256 value) public returns (bool) {
        require(value <= balances[msg.sender], "Insufficient balance");

        balances[msg.sender] = balances[msg.sender].sub(value);
        balances[to] = balances[to].add(value);

        emit Transfer(msg.sender, to, value);
        return true;
    }

    function transferFrom(address from, address to, uint256 value) public returns (bool) {
        require(value <= balances[from], "Insufficient balance");
        require(value <= allowed[from][msg.sender], "Insufficient allowance");

        balances[from] = balances[from].sub(value);
        balances[to] = balances[to].add(value);
        allowed[from][msg.sender] = allowed[from][msg.sender].sub(value);

        emit Transfer(from, 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];
    }
}