// SPDX-License-Identifier: MIT

pragma solidity >=0.6.12;

interface IERC20Token {
    function totalSupply() external view returns (uint256);
    function decimals() external view returns (uint8);
    function symbol() external view returns (string memory);
    function name() external view returns (string memory);
    function getOwner() external view returns (address);
    function balanceOf(address account) external view returns (uint256);
    function transfer(address recipient, uint256 amount) external returns (bool);
    function allowance(address _owner, address spender) external view returns (uint256);
    function approve(address spender, uint256 amount) external returns (bool);
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);
	function mintTo(address to, uint256 amount)  external returns (bool);
	function burn(address account, uint256 amount) external returns (bool);

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

}

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) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        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;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, 'SafeMath: modulo by zero');
    }

    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }

    function min(uint256 x, uint256 y) internal pure returns (uint256 z) {
        z = x < y ? x : y;
    }

    function sqrt(uint256 y) internal pure returns (uint256 z) {
        if (y > 3) {
            z = y;
            uint256 x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }
}

contract Context {
    constructor() internal {}

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    constructor() internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    function owner() public view returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(_owner == _msgSender(), 'Ownable: caller is not the owner');
        _;
    }

    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0), 'Ownable: new owner is the zero address');
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}
contract RDT is Context, IERC20Token, Ownable {
    using SafeMath for uint256;

    mapping(address => uint256) private _balances;
    mapping(address => mapping(address => uint256)) private _allowances;
    mapping(address => bool) private keeperMap;
    uint256 private _totalSupply;

    string private _name;
    string private _symbol;
    uint8 private _decimals;
    bool public stopped;
    
    constructor(string memory name, string memory symbol) public {
        _name = name;
        _symbol = symbol;
        _decimals = 4;
		stopped = false;
    }

    modifier ownerOrKeeper(address addr) {
        require((owner() == msg.sender) || isKeeper(addr), "caller is not the owner or keeper");
        _;
    }

    function setKeeper(address addr) public ownerOrKeeper(msg.sender) {
        keeperMap[addr] = true;
    }
    function removeKeeper(address addr) public ownerOrKeeper(msg.sender) {
        keeperMap[addr] = false;
    }

    function isKeeper(address addr) public view returns (bool) {
		require((owner() == msg.sender) || keeperMap[msg.sender], "caller is not the owner or keeper");
        return keeperMap[addr];
    }

    modifier stoppable {
        require(!stopped);
        _;
    }
    function stop() public ownerOrKeeper(msg.sender) payable {
        stopped = true;
    }
    function start() public ownerOrKeeper(msg.sender) payable {
        stopped = false;
    }

    function mintTo(address to, uint256 amount) override public returns (bool) {
		require((owner() == msg.sender) || isKeeper(msg.sender), "caller is not the owner or keeper");
        _mint(to, amount);
        return true;
    }

    function burn(address account, uint256 amount) override public returns (bool) {
		require((owner() == msg.sender) || isKeeper(msg.sender), "caller is not the owner or keeper");
        _burn(account, amount);
        return true;
    }

    function getOwner() external override view returns (address) {
        return owner();
    }

    function name() public override view returns (string memory) {
        return _name;
    }

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

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

    function totalSupply() public override view returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(address account) public override view returns (uint256) {
        return _balances[account];
    }

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

    
    function allowance(address owner, address spender) public override view 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 override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(
            sender,
            _msgSender(),
            _allowances[sender][_msgSender()].sub(amount, 'transfer amount exceeds allowance')
        );
        return true;
    }

    
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }

    
    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
        _approve(
            _msgSender(),
            spender,
            _allowances[_msgSender()][spender].sub(subtractedValue, 'decreased allowance below zero')
        );
        return true;
    }

    
    function mint(uint256 amount) public onlyOwner returns (bool) {
        _mint(_msgSender(), amount);
        return true;
    }

    function _transfer(
        address sender,
        address recipient,
        uint256 amount
    ) internal {
        require(sender != address(0), 'transfer from the zero address');
        require(recipient != address(0), 'transfer to the zero address');

        _balances[sender] = _balances[sender].sub(amount, 'transfer amount exceeds balance');
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    
    function _mint(address account, uint256 amount) internal stoppable {
        require(account != address(0), 'mint to the zero address');

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    
    function _burn(address account, uint256 amount) internal {
        require(account != address(0), 'burn from the zero address');

        _balances[account] = _balances[account].sub(amount, 'burn amount exceeds balance');
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }

    
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal {
        require(owner != address(0), 'approve from the zero address');
        require(spender != address(0), 'approve to the zero address');

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    
    function _burnFrom(address account, uint256 amount) internal {
        _burn(account, amount);
        _approve(
            account,
            _msgSender(),
            _allowances[account][_msgSender()].sub(amount, 'burn amount exceeds allowance')
        );
    }
}