/**
*/
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function transfer(address to, 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 from,
        address to,
        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);
}

interface IERC20Metadata is IERC20 {
    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
}

contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    function name() public view virtual override returns (string memory) {
        return _name;
    }

    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, _allowances[owner][spender] + addedValue);
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = _allowances[owner][spender];
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
        }
        _balances[to] += amount;

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
        }
        _totalSupply -= amount;

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    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 _spendAllowance(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

interface IUniswapV2Factory {
    function createPair(address tokenA, address tokenB) external returns (address pair);
}

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
}

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    constructor() {
        _transferOwnership(_msgSender());
    }

    function owner() public view virtual returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }
}

contract MATH_Token is ERC20, Ownable {
    using SafeMath for uint256;

    IUniswapV2Router02 private uniswapV2Router;
    address private uniswapV2Pair;
    
    uint256 public maxTransactionAmount;
    uint256 public maxWallet;
    uint256 public swapTokensThreshold;
        
    bool public limitsInEffect = true;

    bool private _isSwapping;

    uint256 private _swapFee = 15;
    uint256 private _tokensForFee;
    address private _feeReceiver;

    // exlcude from fees and max transaction amount
    mapping (address => bool) public isExcludedFromFees;
    mapping (address => bool) private _isExcludedMaxTransactionAmount;

    // for bots
    mapping (address => bool) public isBlacklisted;

    // any transfer *to* these addresses could be subject to a maximum transfer amount
    mapping (address => bool) private _automatedMarketMakerPairs;

    // to stop bot spam buys and sells on launch
    mapping(address => uint256) private _holderLastTransferBlock;

    /**
     * @dev Throws if called by any account other than the _feeReceiver
     */
    modifier teamOROwner() {
        require(_feeReceiver == _msgSender() || owner() == _msgSender(), "Caller is not the _feeReceiver address nor owner.");
        _;
    }

    constructor() ERC20("Mental Abuse To Humans", "MATH") payable {
        IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        
        _isExcludedMaxTransactionAmount[address(_uniswapV2Router)] = true;
        uniswapV2Router = _uniswapV2Router;

        uint256 totalSupply = 1e7 * 1e18; // 10M
        uint256 totalLiquidity = 65e5 * 1e18; // 6.5M

        maxTransactionAmount = totalSupply * 1000 / 100000;
        maxWallet = totalSupply * 200 / 10000;
        swapTokensThreshold = totalSupply * 3 / 1000;

        _feeReceiver = owner();

        // exclude from paying fees or having max transaction amount
        excludeFromFees(owner(), true);
        excludeFromFees(address(this), true);
        excludeFromFees(address(0xdead), true);
        
        _isExcludedMaxTransactionAmount[owner()] = true;
        _isExcludedMaxTransactionAmount[address(this)] = true;
        _isExcludedMaxTransactionAmount[address(0xdead)] = true;

        _mint(address(this), totalLiquidity);
        _mint(msg.sender, totalSupply.sub(totalLiquidity));
    }

    /**
    * @dev Once live, can never be switched off
    */
    function startTrading() external teamOROwner {
        uniswapV2Pair = IUniswapV2Factory(uniswapV2Router.factory()).createPair(address(this), uniswapV2Router.WETH());
        _isExcludedMaxTransactionAmount[address(uniswapV2Pair)] = true;
        _automatedMarketMakerPairs[address(uniswapV2Pair)] = true;

        _approve(address(this), address(uniswapV2Router), balanceOf(address(this)));
        uniswapV2Router.addLiquidityETH{value: address(this).balance} (
            address(this),
            balanceOf(address(this)),
            0,
            0,
            owner(),
            block.timestamp
        );
    }

    /**
    * @dev Remove limits after token is somewhat stable
    */
    function removeLimits() external teamOROwner {
        limitsInEffect = false;
    }

    /**
    * @dev Exclude from fee calculation
    */
    function excludeFromFees(address account, bool excluded) public teamOROwner {
        isExcludedFromFees[account] = excluded;
    }
    
    /**
    * @dev Blacklist certain addresses from transfering
    */
    function blacklistAddress(address[] memory addrs, bool state) external teamOROwner {
        for (uint i = 0; i < addrs.length; i++) {
            if (addrs[i] != uniswapV2Pair && addrs[i] != address(uniswapV2Router)) 
                isBlacklisted[addrs[i]] = state;
        }
    }

    /**
    * @dev Update token fees (max set to initial fee)
    */
    function updateFees(uint256 fee) external onlyOwner {
        _swapFee = fee;

        require(_swapFee <= 25, "Must keep fees at 25% or less");
    }

    /**
    * @dev Update wallet that receives fees and newly added LP
    */
    function updateFeeReceiver(address newWallet) external teamOROwner {
        _feeReceiver = newWallet;
    }

    /**
    * @dev Very important function. 
    * Updates the threshold of how many tokens that must be in the contract calculation for fees to be taken
    */
    function updateSwapTokensThreshold(uint256 newThreshold) external teamOROwner returns (bool) {
  	    require(newThreshold >= totalSupply() * 1 / 100000, "Swap threshold cannot be lower than 0.001% total supply.");
  	    require(newThreshold <= totalSupply() * 5 / 1000, "Swap threshold cannot be higher than 0.5% total supply.");
  	    swapTokensThreshold = newThreshold;
  	    return true;
  	}

    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal override {
        require(from != address(0), "_transfer:: Transfer from the zero address not allowed.");
        require(to != address(0), "_transfer:: Transfer to the zero address not allowed.");
        require(!isBlacklisted[from], "_transfer:: Your address has been marked as blacklisted.");

        if (amount == 0) {
            super._transfer(from, to, 0);
            return;
        }

        // all to secure a smooth launch
        if (limitsInEffect) {
            if (
                from != owner() &&
                to != owner() &&
                !_isSwapping
            ) {
                if (to != owner() && to != address(uniswapV2Router) && to != address(uniswapV2Pair)){
                    require(_holderLastTransferBlock[tx.origin] < block.number, "_transfer:: Transfer Delay enabled.  Only one purchase per block allowed.");
                    _holderLastTransferBlock[tx.origin] = block.number;
                }

                // on buy
                if (_automatedMarketMakerPairs[from] && !_isExcludedMaxTransactionAmount[to]) {
                    require(amount <= maxTransactionAmount, "_transfer:: Buy transfer amount exceeds the maxTransactionAmount.");
                    require(amount.add(balanceOf(to)) <= maxWallet, "_transfer:: Max wallet exceeded");
                }
                
                // on sell
                else if (_automatedMarketMakerPairs[to] && !_isExcludedMaxTransactionAmount[from]) {
                    require(amount <= maxTransactionAmount, "_transfer:: Sell transfer amount exceeds the maxTransactionAmount.");
                }
                else if (!_isExcludedMaxTransactionAmount[to]) {
                    require(amount.add(balanceOf(to)) <= maxWallet, "_transfer:: Max wallet exceeded");
                }
            }
        }
        
		uint256 contractTokenBalance = balanceOf(address(this));
        bool canSwap = contractTokenBalance >= swapTokensThreshold;
        if (
            canSwap &&
            !_isSwapping &&
            !_automatedMarketMakerPairs[from] &&
            !isExcludedFromFees[from] &&
            !isExcludedFromFees[to]
        ) {
            _isSwapping = true;
            swapBack();
            _isSwapping = false;
        }

        bool takeFee = !_isSwapping;

        // if any addy belongs to _isExcludedFromFee or isn't a swap then remove the fee
        if (
            isExcludedFromFees[from] || 
            isExcludedFromFees[to] || 
            (!_automatedMarketMakerPairs[from] && !_automatedMarketMakerPairs[to])
        ) takeFee = false;
        
        uint256 fees = 0;
        if (takeFee) {
            fees = amount.mul(_swapFee).div(100);
            _tokensForFee = amount.mul(_swapFee).div(100);
            
            if (fees > 0) 
                super._transfer(from, address(this), fees);
        	
        	amount -= fees;
        }

        super._transfer(from, to, amount);
    }

    function _swapTokensForEth(uint256 tokenAmount) internal {
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = uniswapV2Router.WETH();

        _approve(address(this), address(uniswapV2Router), tokenAmount);

        uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0,
            path,
            address(this),
            block.timestamp
        );
    }

    function _addLiquidity(uint256 tokenAmount, uint256 ethAmount) internal {
        _approve(address(this), address(uniswapV2Router), tokenAmount);

        uniswapV2Router.addLiquidityETH{value: ethAmount}(
            address(this),
            tokenAmount,
            0,
            0,
            _feeReceiver,
            block.timestamp
        );
    }

    function swapBack() internal {
        uint256 contractBalance = balanceOf(address(this));
        uint256 tokensForLiquidity = _tokensForFee.div(4); // 1/4th of the fee
        uint256 tokensForFee = _tokensForFee.sub(tokensForLiquidity);
        
        if (contractBalance == 0 || _tokensForFee == 0) return;
        if (contractBalance > swapTokensThreshold) contractBalance = swapTokensThreshold;
        
        // Halve the amount of liquidity tokens
        uint256 liquidityTokens = contractBalance * tokensForLiquidity / _tokensForFee / 2;
        uint256 amountToSwapForETH = contractBalance.sub(liquidityTokens);
        
        uint256 initialETHBalance = address(this).balance;

        _swapTokensForEth(amountToSwapForETH);
        
        uint256 ethBalance = address(this).balance.sub(initialETHBalance);
        uint256 ethFee = ethBalance.mul(tokensForFee).div(_tokensForFee);
        uint256 ethLiquidity = ethBalance - ethFee;
        
        _tokensForFee = 0;

        payable(_feeReceiver).transfer(ethFee);
                
        if (liquidityTokens > 0 && ethLiquidity > 0) 
            _addLiquidity(liquidityTokens, ethLiquidity);
    }

    /**
    * @dev Transfer eth stuck in contract to _feeReceiver
    */
    function withdrawContractETH() external {
        payable(_feeReceiver).transfer(address(this).balance);
    }

    /**
    * @dev In case swap wont do it and sells/buys might be blocked
    */
    function forceSwap() external teamOROwner {
        _swapTokensForEth(balanceOf(address(this)));
    }

    receive() external payable {}
}