// SPDX-License-Identifier: Unlicensed

pragma solidity ^0.8.4;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }
}

interface IERC20 {
    function totalSupply() external view returns (uint256);

    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);

    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) {
        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 Ownable is Context {
    address private _owner;
    address private _previousOwner;
    event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
    );

    constructor() {
        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 virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }
}

contract DentistCoin is Context, IERC20, Ownable {
    using SafeMath for uint256;

    string private constant _name = "DentistCoin";
    string private constant _symbol = "DEN";
    uint8 private constant _decimals = 9;

    mapping(address => uint256) private _rOwned;
    mapping(address => uint256) private _tOwned;
    mapping(address => mapping(address => uint256)) private _allowances;
    mapping(address => bool) private _isExcludedFromFee;
    uint256 private constant MAX = ~uint256(0);

    uint256 private constant _tTotal = 921*10**6*10**9;
    uint256 private _rTotal = (MAX - (MAX % _tTotal));
    uint256 private _tFeeTotal;
    uint256 private _taxFee = 20;
    uint256 private _charityFee = 30;

    event ExcludeFromFee(address userAddress);
    event IncludeInFee(address userAddress);
    event UpdatedTaxFee(uint256);
    event UpdatedCharityFee(uint256);

    address payable private _charityAddress;

    constructor(address payable addr1) {
        _charityAddress = addr1;
        _rOwned[_msgSender()] = _rTotal;
        _isExcludedFromFee[owner()] = true;
        _isExcludedFromFee[address(this)] = true;
        _isExcludedFromFee[_charityAddress] = true;
        emit Transfer(address(0), _msgSender(), _tTotal);
    }

    function name() public pure returns (string memory) {
        return _name;
    }

    function symbol() public pure returns (string memory) {
        return _symbol;
    }

    function decimals() public pure returns (uint8) {
        return _decimals;
    }

    function totalSupply() public pure override returns (uint256) {
        return _tTotal;
    }

    function balanceOf(address account) public view override returns (uint256) {
        return tokenFromReflection(_rOwned[account]);
    }

    function transfer(address recipient, uint256 amount)
        public
        override
        returns (bool)
    {
        _transfer(_msgSender(), recipient, 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 updateCharityAddress(address payable newCharity) external onlyOwner() returns(bool){
        _charityAddress = newCharity;
        return true;
    }

    function getCharityAddress() external view returns(address){
        return _charityAddress;
    }

    function excludeFromFee(address account) public onlyOwner() {
        _isExcludedFromFee[account] = true;
        emit ExcludeFromFee(account);
    }

    function isExcludedFromFee(address account) public view returns(bool) {
        return _isExcludedFromFee[account];
    }

    function includeInFee(address account) public onlyOwner() {
        _isExcludedFromFee[account] = false;
        emit IncludeInFee(account);
    }

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(
            sender,
            _msgSender(),
            _allowances[sender][_msgSender()].sub(
                amount,
                "ERC20: transfer amount exceeds allowance"
            )
        );
        return true;
    }

    function reflectionFromToken(uint256 tAmount, bool deductTransferFee) public view returns(uint256) {
        require(tAmount <= _tTotal, "Amount must be less than supply");
        if (!deductTransferFee) {
            (uint256 rAmount,,,,,) = _getValues(tAmount);
            return rAmount;
        } else {
            (,uint256 rTransferAmount,,,,) = _getValues(tAmount);
            return rTransferAmount;
        }
    }

    function setTaxFeePercent(uint256 taxFee) external onlyOwner() {
        _taxFee = taxFee;
        emit UpdatedTaxFee(_taxFee);
    }

    function setCharityFeePercent(uint256 charityFee) external onlyOwner() {
        _charityFee = charityFee;
        emit UpdatedCharityFee(_charityFee);
    }

    function tokenFromReflection(uint256 rAmount)
        private
        view
        returns (uint256)
    {
        require(
            rAmount <= _rTotal,
            "Amount must be less than total reflections"
        );
        uint256 currentRate = _getRate();
        return rAmount.div(currentRate);
    }

    function removeAllFee() private {
        if (_taxFee == 0 && _charityFee == 0) return;
        _taxFee = 0;
        _charityFee = 0;
    }

    function restoreAllFee() private {
        _taxFee = 20;
        _charityFee = 30;
    }

    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) private {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");
        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    function _transfer(
        address from,
        address to,
        uint256 amount
    ) private {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
        require(amount > 0, "Transfer amount must be greater than zero");

        bool takeFee = true;

        if (_isExcludedFromFee[from] || _isExcludedFromFee[to]) {
            takeFee = false;
        }

        _tokenTransfer(from, to, amount, takeFee);
    }

    function _tokenTransfer(
        address sender,
        address recipient,
        uint256 amount,
        bool takeFee
    ) private {
        if (!takeFee) removeAllFee();
        _transferStandard(sender, recipient, amount);
        if (!takeFee) restoreAllFee();
    }

    function _transferStandard(
        address sender,
        address recipient,
        uint256 tAmount
    ) private {
        (
            uint256 rAmount,
            uint256 rTransferAmount,
            uint256 rFee,
            uint256 tTransferAmount,
            uint256 tFee,
            uint256 tCharity
        ) = _getValues(tAmount);
        _rOwned[sender] = _rOwned[sender].sub(rAmount);
        _rOwned[recipient] = _rOwned[recipient].add(rTransferAmount);
        _takeCharity(tCharity);
        _reflectFee(rFee, tFee);
        emit Transfer(sender, recipient, tTransferAmount);
    }

    function _takeCharity(uint256 tCharity) private {
        uint256 currentRate = _getRate();
        uint256 rCharity = tCharity.mul(currentRate);
        _rOwned[_charityAddress] = _rOwned[_charityAddress].add(rCharity);
    }

    function _reflectFee(uint256 rFee, uint256 tFee) private {
        _rTotal = _rTotal.sub(rFee);
        _tFeeTotal = _tFeeTotal.add(tFee);
    }

    receive() external payable {}

    function _getValues(uint256 tAmount)
        private
        view
        returns (
            uint256,
            uint256,
            uint256,
            uint256,
            uint256,
            uint256
        )
    {
        (uint256 tTransferAmount, uint256 tFee, uint256 tCharity) =
            _getTValues(tAmount, _taxFee, _charityFee);
        uint256 currentRate = _getRate();
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee) =
            _getRValues(tAmount, tFee, tCharity, currentRate);
        return (rAmount, rTransferAmount, rFee, tTransferAmount, tFee, tCharity);
    }

    function _getTValues(
        uint256 tAmount,
        uint256 taxFee,
        uint256 CharityFee
    )
        private
        pure
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        uint256 tFee = tAmount.mul(taxFee).div(1000);
        uint256 tCharity = tAmount.mul(CharityFee).div(1000);
        uint256 tTransferAmount = tAmount.sub(tFee).sub(tCharity);
        return (tTransferAmount, tFee, tCharity);
    }

    function _getRValues(
        uint256 tAmount,
        uint256 tFee,
        uint256 tCharity,
        uint256 currentRate
    )
        private
        pure
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        uint256 rAmount = tAmount.mul(currentRate);
        uint256 rFee = tFee.mul(currentRate);
        uint256 rCharity = tCharity.mul(currentRate);
        uint256 rTransferAmount = rAmount.sub(rFee).sub(rCharity);
        return (rAmount, rTransferAmount, rFee);
    }

    function _getRate() private view returns (uint256) {
        (uint256 rSupply, uint256 tSupply) = _getCurrentSupply();
        return rSupply.div(tSupply);
    }

    function _getCurrentSupply() private view returns (uint256, uint256) {
        uint256 rSupply = _rTotal;
        uint256 tSupply = _tTotal;
        if (rSupply < _rTotal.div(_tTotal)) return (_rTotal, _tTotal);
        return (rSupply, tSupply);
    }

}