//SPDX-License-Identifier: MIT
pragma solidity 0.8.28;

interface IERC20 {

    function totalSupply() external view returns (uint256);
    
    function symbol() external view returns(string memory);
    
    function name() external view returns(string memory);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);
    
    /**
     * @dev Returns the number of decimal places
     */
    function decimals() external view returns (uint8);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

contract InfinaeonToken is IERC20 {

    // total supply
    uint256 private _totalSupply = 420_000_000 * 10**18;
    // token data
    string private constant _name = "Infinaeon";
    string private constant _symbol = "INF";
    uint8  private constant _decimals = 18;

    // balances
    mapping (address => uint256) private _balances;
    mapping (address => mapping (address => uint256)) private _allowances;

    constructor() {
        _balances[msg.sender] = _totalSupply;
        emit Transfer(address(0), msg.sender, _totalSupply);
    }

    function totalSupply() external view override returns (uint256) { return _totalSupply; }
    function balanceOf(address account) public view override returns (uint256) { return _balances[account]; }
    function allowance(address holder, address spender) external view override returns (uint256) { return _allowances[holder][spender]; }
    
    function name() public pure override returns (string memory) {
        return _name;
    }

    function symbol() public pure override returns (string memory) {
        return _symbol;
    }

    function decimals() public pure override returns (uint8) {
        return _decimals;
    }

    function approve(address spender, uint256 amount) public override returns (bool) {
        _allowances[msg.sender][spender] = amount;
        emit Approval(msg.sender, spender, amount);
        return true;
    }

    /** Transfer Function */
    function transfer(address recipient, uint256 amount) external override returns (bool) {
        return _transferFrom(msg.sender, recipient, amount);
    }

    /** Transfer Function */
    function transferFrom(address sender, address recipient, uint256 amount) external override returns (bool) {
        require(
            amount <= _allowances[sender][msg.sender],
            'Insufficient Allowance'
        );
        unchecked {
            _allowances[sender][msg.sender] -= amount;
        }
        return _transferFrom(sender, recipient, amount);
    }

    function burn(uint256 qty) external {
        require(
            _balances[msg.sender] >= qty, 
            'Insufficient Balance'
        );
        require(
            qty > 0, 
            'Zero Amount'
        );
        unchecked {
            _balances[msg.sender] -= qty;
            _totalSupply -= qty;
        }
        emit Transfer(msg.sender, address(0), qty);
    }

    /** Internal Transfer */
    function _transferFrom(address sender, address recipient, uint256 amount) internal returns (bool) {
        require(
            recipient != address(0),
            'Zero Recipient'
        );
        require(
            amount > 0,
            'Zero Amount'
        );
        require(
            amount <= _balances[sender],
            'Insufficient Balance'
        );
        
        // decrement sender balance
        unchecked {
            _balances[sender] -= amount;
            _balances[recipient] += amount;
        }

        // emit transfer
        emit Transfer(sender, recipient, amount);
        return true;
    }

}

{
  "compilationTarget": {
    "InfinaeonToken.sol": "InfinaeonToken"
  },
  "evmVersion": "paris",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}