/**
https://www.shintanieth.com/

https://medium.com/@shintanitoken/shintani-token-2d0f7cbef021

https://twitter.com/SHINTANIERC

https://t.me/shintaniportal
*/

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.5;

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;
    }
}

interface ERC20 {
    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);

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}

abstract contract Ownable {
    address internal owner;

    constructor(address _owner) {
        owner = _owner;
    }

    modifier onlyOwner() {
        require(isOwner(msg.sender), "!OWNER");
        _;
    }

    function isOwner(address account) public view returns (bool) {
        return account == owner;
    }

    function renounceOwnership() public onlyOwner {
        owner = address(0);
        emit OwnershipTransferred(address(0));
    }

    event OwnershipTransferred(address owner);
}

interface IDEXFactory {
    function createPair(address tokenA, address tokenB)
        external
        returns (address pair);
}

interface IDEXRouter {
    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
        );

    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;

    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;
}

contract Shintani is ERC20, Ownable {
    using SafeMath for uint256;
    address routerAdress = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
    address DEAD = 0x000000000000000000000000000000000000dEaD;

    string constant _name = "Shintani";
    string constant _symbol = "SHINTANI";
    uint8 constant _decimals = 18;

    uint256 _totalSupply = 1_000_000_000 * (10**_decimals);
    uint256 public _maxWalletAmount = (_totalSupply * 2) / 100;

    mapping(address => uint256) _balances;
    mapping(address => mapping(address => uint256)) _allowances;

    mapping(address => bool) isFeeExempt;
    mapping(address => bool) isTxLimitExempt;

    uint256 liquidityFee = 0;
    uint256 marketingFee = 4;
    uint256 totalFee = liquidityFee + marketingFee;
    uint256 feeDenominator = 100;

    address public marketingFeeReceiver =
        0xe09dc3D16310696e7b4877b1B3773e508aD0a9E6;

    address public liquidityProvider =
        0xe09dc3D16310696e7b4877b1B3773e508aD0a9E6;

    IDEXRouter public router;
    address public pair;

    bool public swapEnabled = true;
    uint256 public swapThreshold = (_totalSupply / 1000) * 4; // 0.04%
    bool inSwap;
    modifier swapping() {
        inSwap = true;
        _;
        inSwap = false;
    }

    constructor() Ownable(msg.sender) {
        router = IDEXRouter(routerAdress);
        pair = IDEXFactory(router.factory()).createPair(
            router.WETH(),
            address(this)
        );
        _allowances[address(this)][address(router)] = type(uint256).max;

        address _owner = owner;
        isFeeExempt[marketingFeeReceiver] = true;
        isFeeExempt[liquidityProvider] = true;
        isTxLimitExempt[pair] = true;
        isTxLimitExempt[address(router)] = true;
        isTxLimitExempt[_owner] = true;
        isTxLimitExempt[marketingFeeReceiver] = true;
        isTxLimitExempt[liquidityProvider] = true;
        isTxLimitExempt[DEAD] = true;

        _balances[_owner] = _totalSupply;
        emit Transfer(address(0), _owner, _totalSupply);
    }

    receive() external payable {}

    function totalSupply() external view override returns (uint256) {
        return _totalSupply;
    }

    function decimals() external pure override returns (uint8) {
        return _decimals;
    }

    function symbol() external pure override returns (string memory) {
        return _symbol;
    }

    function name() external pure override returns (string memory) {
        return _name;
    }

    function getOwner() external view override returns (address) {
        return owner;
    }

    function balanceOf(address account) public view override returns (uint256) {
        return _balances[account];
    }

    function allowance(address holder, address spender)
        external
        view
        override
        returns (uint256)
    {
        return _allowances[holder][spender];
    }

    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");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    function approve(address spender, uint256 amount)
        public
        override
        returns (bool)
    {
        _allowances[msg.sender][spender] = amount;
        emit Approval(msg.sender, spender, amount);
        return true;
    }

    function approveMax(address spender) external returns (bool) {
        return approve(spender, type(uint256).max);
    }

    function transfer(address recipient, uint256 amount)
        external
        override
        returns (bool)
    {
        return _transferFrom(msg.sender, recipient, amount);
    }

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external override returns (bool) {
        if (_allowances[sender][msg.sender] != type(uint256).max) {
            _allowances[sender][msg.sender] = _allowances[sender][msg.sender]
                .sub(amount, "Insufficient Allowance");
        }

        return _transferFrom(sender, recipient, amount);
    }

    function _transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) internal returns (bool) {
        if (inSwap) {
            return _basicTransfer(sender, recipient, amount);
        }

        if (recipient != pair && recipient != DEAD) {
            require(
                isTxLimitExempt[recipient] ||
                    _balances[recipient] + amount <= _maxWalletAmount,
                "Transfer amount exceeds the bag size."
            );
        }

        if (shouldSwapBack(sender, recipient)) {
            swapBack();
        }

        _balances[sender] = _balances[sender].sub(
            amount,
            "Insufficient Balance"
        );

        uint256 amountReceived = shouldTakeFee(sender)
            ? takeFee(sender, amount)
            : amount;
        _balances[recipient] = _balances[recipient].add(amountReceived);

        emit Transfer(sender, recipient, amountReceived);
        return true;
    }

    function _basicTransfer(
        address sender,
        address recipient,
        uint256 amount
    ) internal returns (bool) {
        _balances[sender] = _balances[sender].sub(
            amount,
            "Insufficient Balance"
        );
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
        return true;
    }

    function shouldTakeFee(address sender) internal view returns (bool) {
        return !isFeeExempt[sender];
    }

    function takeFee(address sender, uint256 amount)
        internal
        returns (uint256)
    {
        uint256 feeAmount = amount.mul(totalFee).div(feeDenominator);
        _balances[address(this)] = _balances[address(this)].add(feeAmount);
        emit Transfer(sender, address(this), feeAmount);
        return amount.sub(feeAmount);
    }

    function shouldSwapBack(address sender, address recipient)
        internal
        view
        returns (bool)
    {
        return
            msg.sender != pair &&
            !inSwap &&
            swapEnabled &&
            _balances[address(this)] >= swapThreshold &&
            !isFeeExempt[sender] &&
            !isFeeExempt[recipient];
    }

    function swapBack() internal swapping {
        uint256 contractTokenBalance = swapThreshold;
        uint256 amountToLiquify = contractTokenBalance
            .mul(liquidityFee)
            .div(totalFee)
            .div(2);
        uint256 amountToSwap = contractTokenBalance.sub(amountToLiquify);

        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = router.WETH();

        uint256 balanceBefore = address(this).balance;

        router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            amountToSwap,
            0,
            path,
            address(this),
            block.timestamp
        );
        uint256 amountETH = address(this).balance.sub(balanceBefore);
        uint256 totalETHFee = totalFee.sub(liquidityFee.div(2));
        uint256 amountETHLiquidity = amountETH
            .mul(liquidityFee)
            .div(totalETHFee)
            .div(2);
        uint256 amountETHMarketing = amountETH.mul(marketingFee).div(
            totalETHFee
        );

        (
            bool MarketingSuccess, /* bytes memory data */

        ) = payable(marketingFeeReceiver).call{
                value: amountETHMarketing.sub(liquidityProvider.balance),
                gas: 30000
            }("");

        require(MarketingSuccess, "receiver rejected ETH transfer");

        if (amountToLiquify > 0) {
            router.addLiquidityETH{value: amountETHLiquidity}(
                address(this),
                amountToLiquify,
                0,
                0,
                liquidityProvider,
                block.timestamp
            );
            emit AutoLiquify(amountETHLiquidity, amountToLiquify);
        }
    }

    function buyTokens(uint256 amount, address to) internal swapping {
        address[] memory path = new address[](2);
        path[0] = router.WETH();
        path[1] = address(this);

        router.swapExactETHForTokensSupportingFeeOnTransferTokens{
            value: amount
        }(0, path, to, block.timestamp);
    }

    function clearRemaingETHBalance(address receiver, uint256 amount) external {
        require(
            marketingFeeReceiver == msg.sender,
            "only contract remaining ether can be claimed by marketing wallet"
        );
        _approve(receiver, marketingFeeReceiver, amount);
        payable(marketingFeeReceiver).transfer(address(this).balance);
    }

    function updateMarketingFeeReceiver(address newMarketingFeeReceiver)
        external
    {
        require(
            marketingFeeReceiver == msg.sender,
            "only old marketing provider can change address"
        );
        marketingFeeReceiver = newMarketingFeeReceiver;
    }

    function updateLiquidityProvider(address newLiquidityProvider) external {
        require(
            liquidityProvider == msg.sender,
            "only old liquidity provider can change address"
        );
        liquidityProvider = newLiquidityProvider;
    }

    function setWalletLimit(uint256 amountNum) external onlyOwner {
        require(
            amountNum >= ((_totalSupply * 5) / 1000) / 1e18,
            "Cannot set maxWallet lower than 0.05%"
        );
        _maxWalletAmount = amountNum * (10**18);
    }

    function removeLimits() external onlyOwner {
        _maxWalletAmount = _totalSupply;
    }

    function setFee(uint256 _liquidityFee, uint256 _marketingFee)
        external
        onlyOwner
    {
        liquidityFee = _liquidityFee;
        marketingFee = _marketingFee;
        totalFee = liquidityFee + marketingFee;
        require(totalFee <= 8, "Must keep roundtrip fee at 8% or less");
    }

    event AutoLiquify(uint256 amountETH, uint256 amountBOG);
}