// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.9.0;

interface IERC20 {
    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);
}

interface IFactoryV2 {
    event PairCreated(address indexed token0, address indexed token1, address lpPair, uint);
    function getPair(address tokenA, address tokenB) external view returns (address lpPair);
    function createPair(address tokenA, address tokenB) external returns (address lpPair);
}

interface IV2Pair {
    function factory() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function sync() external;
}

interface IRouter01 {
    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);
    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function swapExactETHForTokens(
        uint amountOutMin, 
        address[] calldata path, 
        address to, uint deadline
    ) external payable returns (uint[] memory amounts);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

interface IRouter02 is IRouter01 {
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;
    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
}

interface Initializer {
    function setLaunch(address _initialLpPair, uint32 _liqAddBlock, uint64 _liqAddStamp, uint8 dec) external;
    function getConfig() external returns (address, address);
    function setLpPair(address pair, bool enabled) external;
}

contract XVSMETA is IERC20 {
    mapping (address => uint256) private _tOwned;
    mapping (address => bool) lpPairs;
    uint256 private timeSinceLastPair = 0;
    mapping (address => mapping (address => uint256)) private _allowances;
    mapping (address => bool) private _liquidityHolders;
    mapping (address => bool) private _isExcludedFromProtection;
   
    uint256 constant private startingSupply = 50_000_000;
    string constant private _name = "X VS META";
    string constant private _symbol = "$XVM";
    uint8 constant private _decimals = 18;
    uint256 constant private _tTotal = startingSupply * 10**_decimals;

    IRouter02 public dexRouter;
    address public lpPair;
    address constant public DEAD = 0x000000000000000000000000000000000000dEaD;
    bool public tradingEnabled = false;
    bool public _hasLiqBeenAdded = false;
    Initializer initializer;

    constructor () payable {
        // Set the owner.
        _owner = msg.sender;
        _liquidityHolders[_owner] = true;
        _tOwned[_owner] = _tTotal;
        emit Transfer(address(0), _owner, _tTotal);
    }

    receive() external payable {}

//===============================================================================================================
//===============================================================================================================
//===============================================================================================================
    // Ownable removed as a lib and added here to allow for custom transfers and renouncements.
    // This allows for removal of ownership privileges from the owner once renounced or transferred.

    address private _owner;

    modifier onlyOwner() { require(_owner == msg.sender, "Caller =/= owner."); _; }
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    function transferOwner(address newOwner) external onlyOwner {
        require(newOwner != address(0), "Call renounceOwnership to transfer owner to the zero address.");
        require(newOwner != DEAD, "Call renounceOwnership to transfer owner to the zero address.");
        if (balanceOf(_owner) > 0) {
            finalizeTransfer(_owner, newOwner, balanceOf(_owner), true);
        }
        
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
        
    }

    function renounceOwnership() external onlyOwner {
        require(tradingEnabled, "Cannot renounce until trading has been enabled.");
        address oldOwner = _owner;
        _owner = address(0);
        emit OwnershipTransferred(oldOwner, address(0));
    }

//===============================================================================================================
//===============================================================================================================
//===============================================================================================================

    function totalSupply() external pure override returns (uint256) { if (_tTotal == 0) { revert(); } return _tTotal; }
    function decimals() external pure override returns (uint8) { if (_tTotal == 0) { revert(); } 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 allowance(address holder, address spender) external view override returns (uint256) { return _allowances[holder][spender]; }
    function balanceOf(address account) public view override returns (uint256) {
        return _tOwned[account];
    }

    function transfer(address recipient, uint256 amount) public override returns (bool) {
        _transfer(msg.sender, recipient, amount);
        return true;
    }

    function approve(address spender, uint256 amount) external override returns (bool) {
        _approve(msg.sender, spender, amount);
        return true;
    }

    function _approve(address sender, address spender, uint256 amount) internal {
        require(sender != address(0), "ERC20: Zero Address");
        require(spender != address(0), "ERC20: Zero Address");

        _allowances[sender][spender] = amount;
        emit Approval(sender, spender, amount);
    }

    function approveContractContingency() external onlyOwner returns (bool) {
        _approve(address(this), address(dexRouter), type(uint256).max);
        return true;
    }

    function transferFrom(address sender, address recipient, uint256 amount) external override returns (bool) {
        if (_allowances[sender][msg.sender] != type(uint256).max) {
            _allowances[sender][msg.sender] -= amount;
        }

        return _transfer(sender, recipient, amount);
    }
    
    function setNewRouter(address newRouter) external onlyOwner {
        require(!_hasLiqBeenAdded, "Cannot change after liquidity.");
        IRouter02 _newRouter = IRouter02(newRouter);
        lpPairs[lpPair] = false;
        address get_pair = IFactoryV2(_newRouter.factory()).getPair(address(this), _newRouter.WETH());
        if (get_pair == address(0)) {
            lpPair = IFactoryV2(_newRouter.factory()).createPair(address(this), _newRouter.WETH());
        }
        else {
            lpPair = get_pair;
        }
        dexRouter = _newRouter;
        lpPairs[lpPair] = true;
        _approve(address(this), address(dexRouter), type(uint256).max);
    }

    function setLpPair(address pair, bool enabled) external onlyOwner {
        if (!enabled) {
            lpPairs[pair] = false;
            initializer.setLpPair(pair, false);
        } else {
            if (timeSinceLastPair != 0) {
                require(block.timestamp - timeSinceLastPair > 3 days, "3 Day cooldown.");
            }
            require(!lpPairs[pair], "Pair already added to list.");
            lpPairs[pair] = true;
            timeSinceLastPair = block.timestamp;
            initializer.setLpPair(pair, true);
        }
    }

    function setInitializer(address _initializer) public onlyOwner {
        require(!tradingEnabled);
        require(_initializer != address(this), "Can't be self.");
        initializer = Initializer(_initializer);
        try initializer.getConfig() returns (address router, address constructorLP) {
            dexRouter = IRouter02(router); lpPair = constructorLP; lpPairs[constructorLP] = true;
            _approve(_owner, address(dexRouter), type(uint256).max);
            _approve(address(this), address(dexRouter), type(uint256).max);
        } catch { revert(); }
    }

    function isExcludedFromProtection(address account) external view returns (bool) {
        return _isExcludedFromProtection[account];
    }

    function setExcludedFromProtection(address account, bool enabled) external onlyOwner {
        _isExcludedFromProtection[account] = enabled;
    }

    function getCirculatingSupply() public view returns (uint256) {
        return (_tTotal - (balanceOf(DEAD) + balanceOf(address(0))));
    }

    function _hasLimits(address from, address to) internal view returns (bool) {
        return from != _owner
            && to != _owner
            && tx.origin != _owner
            && !_liquidityHolders[to]
            && !_liquidityHolders[from]
            && to != DEAD
            && to != address(0)
            && from != address(this)
            && from != address(initializer)
            && to != address(initializer);
    }

    function _transfer(address from, address to, uint256 amount) internal returns (bool) {
        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 buy = false;
        bool sell = false;
        bool other = false;
        if (lpPairs[from]) {
            buy = true;
        } else if (lpPairs[to]) {
            sell = true;
        } else {
            other = true;
        }
        if (_hasLimits(from, to)) {
            if(!tradingEnabled) {
                if (!other) {
                    revert("Trading not yet enabled!");
                } else if (!_isExcludedFromProtection[from] && !_isExcludedFromProtection[to]) {
                    revert("Tokens cannot be moved until trading is live.");
                }
            }
        }

        return finalizeTransfer(from, to, amount, other);
    }

    function _checkLiquidityAdd(address from, address to) internal {
        require(!_hasLiqBeenAdded, "Liquidity already added and marked.");
        if (!_hasLimits(from, to) && to == lpPair) {
            if (address(initializer) == address(0)){
                initializer = Initializer(address(this));
            } else {
                _liquidityHolders[from] = true;
                _hasLiqBeenAdded = true;
            }
        }
    }

    function enableTrading() public onlyOwner {
        require(!tradingEnabled, "Trading already enabled!");
        require(_hasLiqBeenAdded, "Liquidity must be added.");
        if (address(initializer) == address(0)){
            initializer = Initializer(address(this));
        }
        try initializer.setLaunch(lpPair, uint32(block.number), uint64(block.timestamp), _decimals) {} catch {}
        tradingEnabled = true;
    }

    function sweepBalance() external onlyOwner {
        payable(_owner).transfer(address(this).balance);
    }
    
    function sweepExternalTokens(address token) external onlyOwner {
        IERC20 TOKEN = IERC20(token);
        TOKEN.transfer(_owner, TOKEN.balanceOf(address(this)));
    }

    function multiSendTokens(address[] memory accounts, uint256[] memory amounts) external onlyOwner {
        require(accounts.length == amounts.length, "Lengths do not match.");
        for (uint16 i = 0; i < accounts.length; i++) {
            require(balanceOf(msg.sender) >= amounts[i]*10**_decimals, "Not enough tokens.");
            finalizeTransfer(msg.sender, accounts[i], amounts[i]*10**_decimals, true);
        }
    }

    function finalizeTransfer(address from, address to, uint256 amount, bool other) internal returns (bool) {
        _tOwned[from] -= amount;
        _tOwned[to] += amount;
        emit Transfer(from, to, amount);
        if (!_hasLiqBeenAdded) {
            _checkLiquidityAdd(from, to);
            if (!_hasLiqBeenAdded && _hasLimits(from, to) && !_isExcludedFromProtection[from] && !_isExcludedFromProtection[to] && !other) {
                revert("Pre-liquidity transfer protection.");
            }
        }

        return true;
    }
}