// File: contracts/MultiFarmCapitalV2.sol



// SPDX-License-Identifier: MIT

/**
Multi-Farn Capital v2: $MFC
-You buy on Ethereum, we farm on multiple chains and return the profits to $MFC holders.

Tokenomics:
10% of each buy goes to existing holders.
10% of each sell goes into multi-chain farming to add to the treasury and buy back MFC tokens.

Website:
https://multifarmcapital.io/

Telegram:
https://t.me/MultiFarmCapital

Twitter:
https://twitter.com/MultiFarmCap

Medium:
https://medium.com/@multifarmcapital
*/

pragma solidity >=0.6.0;
import './external/Address.sol';
import './external/Ownable.sol';
import './external/IERC20.sol';
import './external/SafeMath.sol';
import './external/Uniswap.sol';
import './external/ReentrancyGuard.sol';

contract MultiFarmCapital is Context, IERC20, Ownable {
    using SafeMath for uint256;
    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 = 1500_000_000_000 * 10**9;
    uint256 private _rTotal = (MAX - (MAX % _tTotal));
    uint256 private _tFeeTotal;

    string private constant _name = 'Multi Farm Capital v2';
    string private constant _symbol = 'MFC';

    uint8 private constant _decimals = 9;
    uint256 private _taxFee = 10;
    uint256 private _teamFee = 10;
    uint256 private _previousTaxFee = _taxFee;
    uint256 private _previousteamFee = _teamFee;
    address payable private w1;
    address payable private w2;
    address payable private w3;
    IUniswapV2Router02 private uniswapRouter;
    address public uniswapPair;
    bool private tradingEnabled = false;
    bool private canSwap = true;
    bool private inSwap = false;

    event MaxBuyAmountUpdated(uint256 _maxBuyAmount);
    event CooldownEnabledUpdated(bool _cooldown);
    event FeeMultiplierUpdated(uint256 _multiplier);
    event FeeRateUpdated(uint256 _rate);

    modifier lockTheSwap() {
        inSwap = true;
        _;
        inSwap = false;
    }

    constructor(
        address payable treasuryWalletAddress,
        address payable marketingWaletAddress,
        address payable devWallet
    ) public {
        w1 = treasuryWalletAddress;
        w2 = marketingWaletAddress;
        w3 = devWallet;
        _rOwned[_msgSender()] = _rTotal;
        _isExcludedFromFee[owner()] = true;
        _isExcludedFromFee[address(this)] = true;
        _isExcludedFromFee[w1] = true;
        _isExcludedFromFee[w2] = true;
        _isExcludedFromFee[w3] = true;
        emit Transfer(address(0), _msgSender(), _tTotal);

        IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        uniswapRouter = _uniswapV2Router;
        _approve(address(this), address(uniswapRouter), _tTotal);
        uniswapPair = IUniswapV2Factory(_uniswapV2Router.factory()).createPair(address(this), _uniswapV2Router.WETH());
        IERC20(uniswapPair).approve(address(uniswapRouter), type(uint256).max);
    }

    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 view 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 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 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 setCanSwap(bool onoff) external onlyOwner {
        canSwap = onoff;
    }

    function setTradingEnabled() external onlyOwner {
        tradingEnabled = true;
    }

    function removeAllFee() private {
        if (_taxFee == 0 && _teamFee == 0) return;
        _previousTaxFee = _taxFee;
        _previousteamFee = _teamFee;
        _taxFee = 0;
        _teamFee = 0;
    }

    function restoreAllFee() private {
        _taxFee = _previousTaxFee;
        _teamFee = _previousteamFee;
    }

    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');
        if (!tradingEnabled) {
            require(_isExcludedFromFee[from] || _isExcludedFromFee[to] || _isExcludedFromFee[tx.origin], 'Trading is not live yet');
        }
        uint256 contractTokenBalance = balanceOf(address(this));

        if (!inSwap && from != uniswapPair && tradingEnabled && canSwap) {
            if (contractTokenBalance > 0) {
                if (contractTokenBalance > balanceOf(uniswapPair).div(100)) {
                    swapTokensForEth(contractTokenBalance);
                }
                
            }
            uint256 contractETHBalance = address(this).balance;
            if (contractETHBalance > 0) {
                sendETHToFee(address(this).balance);
            }
        }

        bool takeFee = true;

        if (_isExcludedFromFee[from] || _isExcludedFromFee[to]) {
            takeFee = false;
        }

        if (from != uniswapPair && to != uniswapPair) {
            takeFee = false;
        }

        if (takeFee && from == uniswapPair) {
            _previousteamFee = _teamFee;
            _teamFee = 0;
        }
        if (takeFee && to == uniswapPair) {
            _previousTaxFee = _taxFee;
            _taxFee = 0;
        }
        _tokenTransfer(from, to, amount, takeFee);
        if (takeFee && from == uniswapPair) _teamFee = _previousteamFee;
        if (takeFee && to == uniswapPair) _taxFee = _previousTaxFee;
    }

    function swapTokensForEth(uint256 tokenAmount) private lockTheSwap {
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = uniswapRouter.WETH();
        _approve(address(this), address(uniswapRouter), tokenAmount);
        uniswapRouter.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0,
            path,
            address(this),
            block.timestamp
        );
    }

    function sendETHToFee(uint256 amount) private {
        w1.transfer(amount.div(10).mul(4));
        w2.transfer(amount.div(10).mul(5));
        w3.transfer(amount.div(10).mul(1));
    }

    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 tTeam
        ) = _getValues(tAmount);
        _rOwned[sender] = _rOwned[sender].sub(rAmount);
        _rOwned[recipient] = _rOwned[recipient].add(rTransferAmount);

        _takeTeam(tTeam);
        _reflectFee(rFee, tFee);
        emit Transfer(sender, recipient, tTransferAmount);
    }

    function _getValues(uint256 tAmount)
        private
        view
        returns (
            uint256,
            uint256,
            uint256,
            uint256,
            uint256,
            uint256
        )
    {
        (uint256 tTransferAmount, uint256 tFee, uint256 tTeam) = _getTValues(tAmount, _taxFee, _teamFee);
        uint256 currentRate = _getRate();
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee) = _getRValues(tAmount, tFee, tTeam, currentRate);
        return (rAmount, rTransferAmount, rFee, tTransferAmount, tFee, tTeam);
    }

    function _getTValues(
        uint256 tAmount,
        uint256 taxFee,
        uint256 TeamFee
    )
        private
        pure
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        uint256 tFee = tAmount.mul(taxFee).div(100);
        uint256 tTeam = tAmount.mul(TeamFee).div(100);
        uint256 tTransferAmount = tAmount.sub(tFee).sub(tTeam);
        return (tTransferAmount, tFee, tTeam);
    }

    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);
    }

    function _getRValues(
        uint256 tAmount,
        uint256 tFee,
        uint256 tTeam,
        uint256 currentRate
    )
        private
        pure
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        uint256 rAmount = tAmount.mul(currentRate);
        uint256 rFee = tFee.mul(currentRate);
        uint256 rTeam = tTeam.mul(currentRate);
        uint256 rTransferAmount = rAmount.sub(rFee).sub(rTeam);
        return (rAmount, rTransferAmount, rFee);
    }

    function _takeTeam(uint256 tTeam) private {
        uint256 currentRate = _getRate();
        uint256 rTeam = tTeam.mul(currentRate);

        _rOwned[address(this)] = _rOwned[address(this)].add(rTeam);
    }

    function _reflectFee(uint256 rFee, uint256 tFee) private {
        _rTotal = _rTotal.sub(rFee);
        _tFeeTotal = _tFeeTotal.add(tFee);
    }

    receive() external payable {}

    function setTreasuryWallet(address payable _w1) external onlyOwner {
        w1 = _w1;
        _isExcludedFromFee[w1] = true;
    }

    function setMFCWallet(address payable _w2) external onlyOwner {
        w2 = _w2;
        _isExcludedFromFee[w2] = true;
    }

    function excludeFromFee(address payable ad) external onlyOwner {
        _isExcludedFromFee[ad] = true;
    }

    function includeToFee(address payable ad) external onlyOwner {
        _isExcludedFromFee[ad] = false;
    }

    function setTeamFee(uint256 team) external onlyOwner {
        require(team <= 25, 'Team fee must be less than 25%');
        _teamFee = team;
    }

    function setTaxFee(uint256 tax) external onlyOwner {
        require(tax <= 25, 'Tax fee must be less than 25%');
        _taxFee = tax;
    }

    function manualSwap() external {
        require(_msgSender() == w1 || _msgSender() == w2 || _msgSender() == w3, 'Not authorized');
        uint256 contractBalance = balanceOf(address(this));
        swapTokensForEth(contractBalance);
    }

    function manualSend() external {
        require(_msgSender() == w1 || _msgSender() == w2 || _msgSender() == w3, 'Not authorized');
        uint256 contractETHBalance = address(this).balance;
        sendETHToFee(contractETHBalance);
    }
}

// File: contracts/external/Address.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;

        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            codehash := extcodehash(account)
        }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, 'Address: insufficient balance');

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{value: amount}('');
        require(success, 'Address: unable to send value, recipient may have reverted');
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, 'Address: low-level call failed');
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return _functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, 'Address: low-level call with value failed');
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, 'Address: insufficient balance for call');
        return _functionCallWithValue(target, data, value, errorMessage);
    }

    function _functionCallWithValue(
        address target,
        bytes memory data,
        uint256 weiValue,
        string memory errorMessage
    ) private returns (bytes memory) {
        require(isContract(target), 'Address: call to non-contract');

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{value: weiValue}(data);
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: contracts/external/Ownable.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
import './Context.sol';

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Context {
    address private _owner;

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(_owner == _msgSender(), 'Ownable: caller is not the owner');
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), 'Ownable: new owner is the zero address');
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: contracts/external/IERC20.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

    /**
     * @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);
}

// File: contracts/external/SafeMath.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    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.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    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.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    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.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    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;
    }

    /**
     * @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 Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    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).
     *
     * Requirements:
     *
     * - The divisor cannot be 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;
    }

    /**
     * @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).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    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).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: contracts/external/Uniswap.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;

interface IUniswapV2Factory {
    function createPair(address tokenA, address tokenB) external returns (address pair);
}

interface IUniswapV2Pair {
    function sync() external;
}

interface IUniswapV2Router01 {
    function factory() external pure returns (address);

    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint256 amountADesired,
        uint256 amountBDesired,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    )
        external
        returns (
            uint256 amountA,
            uint256 amountB,
            uint256 liquidity
        );

    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (
            uint256 amountToken,
            uint256 amountETH,
            uint256 liquidity
        );
}

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountETH);

    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;

    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable;
}

// File: contracts/external/ReentrancyGuard.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;

abstract contract ReentrancyGuard {
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() public {
        _status = _NOT_ENTERED;
    }

    modifier nonReentrant() {
        require(_status != _ENTERED, 'ReentrancyGuard: reentrant call');
        _status = _ENTERED;
        _;
        _status = _NOT_ENTERED;
    }

    modifier isHuman() {
        require(tx.origin == msg.sender, 'sorry humans only');
        _;
    }
}

// File: contracts/external/Context.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

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