//SPDX-License-Identifier: MIT
pragma solidity 0.8.18;

/*

SocialAI
https://www.socialai.finance/

Just with a token address, SocialAI instantly finds the associated social media. 
It uses the revolutionary power of AI to scan the wealth of text in the crypto space. 
From comments on tweets to the source codes of websites. 

*/

// Just the basic IERC20 interface
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 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);
}

// We use the Auth contract mainly to have two devs able to interacet with the contract
abstract contract Auth {
    address internal owner;
    mapping (address => bool) internal authorizations;

    constructor(address _owner) {
        owner = _owner;
        authorizations[_owner] = true;
    }

    modifier onlyOwner() {
        require(isOwner(msg.sender), "!OWNER"); _;
    }

    modifier authorized() {
        require(isAuthorized(msg.sender), "!AUTHORIZED"); _;
    }

    function authorize(address adr) public onlyOwner {
        authorizations[adr] = true;
    }

    function unauthorize(address adr) public onlyOwner {
        authorizations[adr] = false;
    }

    function isOwner(address account) public view returns (bool) {
        return account == owner;
    }

    function isAuthorized(address adr) public view returns (bool) {
        return authorizations[adr];
    }

    function transferOwnership(address payable adr) public onlyOwner {
        owner = adr;
        authorizations[adr] = true;
        emit OwnershipTransferred(adr);
    }

    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 addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);

    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

contract SocialAI is IERC20, Auth {
   
    // Constant addresses 
    address constant DEAD = 0x000000000000000000000000000000000000dEaD;
    address constant ZERO = 0x0000000000000000000000000000000000000000;
    IDEXRouter public constant router = IDEXRouter(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);

    // Immutable vars
    address public immutable pair; // After we set the pair we don't have to change it again

    // Token info is constant
    string constant _name = "SocialAI";
    string constant _symbol = "sAI";
    uint8 constant _decimals = 18;

    // Total supply is 1 billion
    uint256 _totalSupply = 1 * (10**9) * (10 ** _decimals);

    // The tax divisor is also constant (and hence immutable)
    // 1000 so we can also use halves, like 2.5%
    uint256 constant taxDivisor = 1_000;
    
    // 10 / 1000 = 0.01 = 1%
    uint256 public _maxTxAmount = _totalSupply * 10 / taxDivisor; 
    uint256 public _maxWalletToken =  _totalSupply * 10 / taxDivisor; 

    // Keep track of wallet balances and approvals (allowance)
    mapping (address => uint256) _balances;
    mapping (address => mapping (address => uint256)) _allowances;

    // Mapping to keep track of what wallets/contracts are exempt
    // from fees
    mapping (address => bool) isFeeExempt;
    mapping (address => bool) isTxLimitExempt; // Both wallet + max TX

    // Also, to keep it organized, a seperate mapping to exclude the presale
    // and locker from limits
    mapping (address => bool) presaleOrlock;

    //fees are mulitplied by 10 to allow decimals, and therefore dividied by 1000 (see takefee)
    uint256 marketingBuyFee = 20;
    uint256 liquidityBuyFee = 20;
    uint256 developmentBuyFee = 20;
    uint256 public totalBuyFee = marketingBuyFee + liquidityBuyFee + developmentBuyFee;

    uint256 marketingSellFee = 30;
    uint256 liquiditySellFee = 30;
    uint256 developmentSellFee = 20;
    uint256 public totalSellFee = marketingSellFee + liquiditySellFee + developmentSellFee;

    // For the sniper friends
    uint256 private sniperTaxTill; 

    // In case anything would go wrong with fees we can just disable them
    bool feesEnabled = true;

    // Whether tx limits should apply or not 
    bool limits = true;

    // To keep track of the tokens collected to swap
    uint256 private tokensForMarketing;
    uint256 private tokensForLiquidity;
    uint256 private tokensForDev;

    // Wallets used to send the fees to
    address public liquidityWallet;
    address public marketingWallet;
    address public developmentWallet;

    // One time trade lock
    bool tradeBlock = true;
    bool lockUsed = false;

    // Contract cant be tricked into spam selling exploit
    uint256 lastSellTime;
    
    // When to swap contract tokens, and how many to swap
    bool public swapEnabled = true;
    uint256 public swapThreshold = _totalSupply * 10 / 100_000; // 0.01%
    event SwapAndLiquify(uint256 tokensSwapped, uint256 ethReceived, uint256 tokensIntoLiquidity);

    // This will just check if the transferf is called from within 
    // the token -> ETH swap when processing the fees (and adding LP)
    bool inSwap;
    modifier swapping() { inSwap = true; _; inSwap = false; }


    constructor () Auth(msg.sender) {
        // Create the lp pair
        pair = IDEXFactory(router.factory()).createPair(router.WETH(), address(this));

        // Exclude the contract
        isFeeExempt[address(this)] = true;
        isTxLimitExempt[address(this)] = true;

        // Exclude the owner
        isFeeExempt[msg.sender] = true;
        isTxLimitExempt[msg.sender] = true;
        
        // Exclude the pair
        isTxLimitExempt[address(pair)] = true; 

        // Exclude the router 
        isTxLimitExempt[address(router)] = true;

        // Set fee receivers
        liquidityWallet = 0xC2c5dCdC771835325aE0eE5EAdBEb18B952CAfDe;
        marketingWallet = 0xb657DafDb4fB36aEb466c04940eC04FBf7c2D5e3;
        developmentWallet = 0x2b47097ae32639025d205cB866972F70deCB5a15;

        // Approve this contract & owner to interact with the 
        // router and pair contract (for swapping)
        _approve(address(this), address(router), _totalSupply);
        _approve(msg.sender, address(pair), _totalSupply);

        // Mint the tokens
        _balances[msg.sender] = _totalSupply;
        emit Transfer(address(0), msg.sender, _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 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 getPair() external view returns (address){return pair;}

    // Internal approve 
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    // Regular approve the contract
    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, _totalSupply);
    }

    // We actually only need to exempt any locks or presale addresses
    // we could use a feeexempt or authorize it, but this is a bit cleaner
    function excludeLockorPresale(address add) external authorized {
        // Exclude from fees
        isFeeExempt[add] = true;
        isTxLimitExempt[add] = true;
        // We want to allow transfers to locks and from the presale
        // address when trading is not yet enabled. 
        presaleOrlock[add] = true;
    }
    
    function _basicTransfer(address sender, address recipient, uint256 amount) internal returns (bool) {
        uint256 senderBalance = _balances[sender];
        // Check if the sender has sufficient balance
        require(senderBalance >= amount, "Insufficient Balance");
        // Update balances
        _balances[sender] = _balances[sender] - amount; 
        _balances[recipient] = _balances[recipient] + amount;
        emit Transfer(sender, recipient, amount);
        return true;
    }

    // Set the buy fees, this can not exceed 15%, 150 / 1000 = 0.15 = 15%
    function setBuyFees(uint256 _marketingFee, uint256 _liquidityFee, uint256 _developFee) external authorized{
        require(_marketingFee + _liquidityFee + _developFee <= 150); // max 15%
        marketingBuyFee = _marketingFee;
        liquidityBuyFee = _liquidityFee;
        developmentBuyFee = _developFee;
        totalBuyFee = _marketingFee + _liquidityFee + _developFee;
    }
    
    // Set the sell fees, this can not exceed 15%, 150 / 1000 = 0.15 = 15%
    function setSellFees(uint256 _marketingFee, uint256 _liquidityFee, uint256 _developFee) external authorized{
        require(_marketingFee + _liquidityFee + _developFee <= 150); // max 15%
        marketingSellFee = _marketingFee;
        liquiditySellFee = _liquidityFee;
        developmentSellFee = _developFee;
        totalSellFee = _marketingFee + _liquidityFee + _developFee;
    }

    // To change the tax receiving wallets
    function setWallets(address _marketingWallet, address _liquidityWallet, address _developWallet) external authorized {
        marketingWallet = _marketingWallet;
        liquidityWallet = _liquidityWallet;
        developmentWallet = _developWallet;
    }

    // To limit the number of tokens a wallet can buy, especially relevant at launch
    function setMaxWallet(uint256 percent) external authorized {
        require(percent >= 10); //should be at least 1% of the total supply (note divisor is 1000)
        _maxWalletToken = ( _totalSupply * percent ) / taxDivisor;
    }

    // To limit the number of tokens per transactions
    function setTxLimit(uint256 percent) external authorized {
        require(percent >= 10); //should be at least 1% of the total supply (note divisor is 1000)
        _maxTxAmount = ( _totalSupply * percent ) / taxDivisor;
    }
    
    function checkLimits(address sender,address recipient, uint256 amount) internal view {
        // If both sender and recipient are excluded we don't have to limit 
        if (isTxLimitExempt[sender] && isTxLimitExempt[recipient]){return;}

        // In any other case we will check whether this is a buy or sell
        // to determine the tx limit
        
        // buy
        if (sender == pair && !isTxLimitExempt[recipient]) {  
            require(amount <= _maxTxAmount, "Max tx limit");

        // sell
        } else if(recipient == pair && !isTxLimitExempt[sender] ) { 
            require(amount <= _maxTxAmount, "Max tx limit");
        }

        // Also check max wallet 
        if (!isTxLimitExempt[recipient]) {
            require(amount + balanceOf(recipient) <= _maxWalletToken, "Max wallet");
        }

    }

    // We will lift the transaction limits just after launch
    function liftLimits() external authorized {
        limits = false;
    }

    // This would make the token fee-less in case taking fees
    // would at any point block transfers. This is reversible
    function setFeeTaking(bool takeFees) external authorized {
        feesEnabled = takeFees;
    }

    // Enable trading - this can only be called once (by just the owner)
    function startTrading() external onlyOwner {
        require(lockUsed == false);
        tradeBlock = false;
        sniperTaxTill = block.number + 2; // (<sniperTaxTill, so first block)
        lockUsed = true;
    }
    
    // When and if to swap the tokens in the contract
    function setTokenSwapSettings(bool _enabled, uint256 _threshold) external authorized {
        swapEnabled = _enabled;
        swapThreshold = _threshold * (10 ** _decimals); 
    }
    
    // Check if the contract should swap tokens
    function shouldTokenSwap(address recipient) internal view returns (bool) {
        return recipient == pair // i.e. is sell
        && lastSellTime + 1 < block.timestamp // block contract spam sells
        && !inSwap
        && swapEnabled
        && _balances[address(this)] >= swapThreshold;
    }

    function takeFee(address from, address to, uint256 amount) internal returns (uint256) {

        // If the sender or receiver is exempt from fees, skip fees
        if (isFeeExempt[from] || isFeeExempt[to]) {
            return amount;
        }

        // This does not charge for wallet-wallet transfers
        uint256 fees;

        // Sniper tax
        if (block.number < sniperTaxTill) {
            fees = amount * 98 / 100; // 98% tax
            tokensForLiquidity += (fees * 50) / 98;
            tokensForMarketing += (fees * 48) / 98;
        }

        // On sell
        else if (to == pair && totalSellFee > 0) {
            fees = amount * totalSellFee / taxDivisor;
            tokensForLiquidity += (fees * liquiditySellFee)   / totalSellFee;
            tokensForDev       += (fees * developmentSellFee) / totalSellFee;
            tokensForMarketing += (fees * marketingSellFee)   / totalSellFee;
        }

        // On buy
        else if (from == pair && totalBuyFee > 0) {
            fees = amount * totalBuyFee / taxDivisor;
            tokensForLiquidity += (fees * liquidityBuyFee)   / totalBuyFee ;
            tokensForDev       += (fees * developmentBuyFee) / totalBuyFee;
            tokensForMarketing += (fees * marketingBuyFee)   / totalBuyFee;
        }

        // If we collected fees, send them to the contract
        if (fees > 0) {
            _basicTransfer(from, address(this), fees);
            emit Transfer(from, address(this), fees);
        }

        // Return the taxed amount
        return amount -= fees;
    }

    
    function swapTokensForEth(uint256 tokenAmount) private {
        // Swap path token -> weth
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = router.WETH();

        // Make the swap
        router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0, 
            path,
            address(this),
            block.timestamp
        );
    }

    function addLiquidity(uint256 tokenAmount, uint256 ethAmount) private {
        // Add liquidity from the contract. Now the LP tokens get send to the lP
        // wallet, but we could also change the LP receiver to the burn address leter
        router.addLiquidityETH{value: ethAmount}(
            address(this),
            tokenAmount,
            0, 
            0, 
            liquidityWallet,
            block.timestamp
        );
    }

    function swapBack() internal swapping {
        uint256 contractBalance = balanceOf(address(this));
        uint256 totalTokensToSwap = tokensForLiquidity + tokensForMarketing + tokensForDev;
        bool success;

        if (contractBalance == 0 || totalTokensToSwap == 0) {return;}
  
        // Halve the amount of liquidity tokens
        uint256 liquidityTokens = (contractBalance * tokensForLiquidity) / totalTokensToSwap / 2;
        uint256 amountToSwapForETH = contractBalance - liquidityTokens;

        uint256 initialETHBalance = address(this).balance;

        // Swap the tokens for ETH
        swapTokensForEth(amountToSwapForETH);

        uint256 ethBalance = address(this).balance - initialETHBalance;
        uint256 ethForMarketing = (ethBalance * tokensForMarketing) / totalTokensToSwap;
        uint256 ethForDev       = (ethBalance * tokensForDev)       / totalTokensToSwap;
        uint256 ethForLiquidity = ethBalance - ethForMarketing - ethForDev;

        // Reset token fee counts
        tokensForLiquidity = 0;
        tokensForMarketing = 0;
        tokensForDev = 0;

        // Send Dev fees
        (success, ) = address(developmentWallet).call{value: ethForDev}("");

        // Add liquidty
        if (liquidityTokens > 0 && ethForLiquidity > 0) {
            addLiquidity(liquidityTokens, ethForLiquidity);
            emit SwapAndLiquify(amountToSwapForETH, ethForLiquidity, tokensForLiquidity);
        }

        // Whatever remains (this should be ~ethForMarketing) send to the marketing wallet
        (success, ) = address(marketingWallet).call{value: address(this).balance}("");

        lastSellTime = block.timestamp;
    }

    function transfer(address recipient, uint256 amount) external override returns (bool) {
        if (owner == msg.sender){
            return _basicTransfer(msg.sender, recipient, amount);
        }
        else {
            return _transferFrom(msg.sender, recipient, amount);
        }
    }

    function transferFrom(address sender, address recipient, uint256 amount) external override returns (bool) {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");
        if(_allowances[sender][msg.sender] != _totalSupply){
            // Get the current allowance
            uint256 curAllowance =  _allowances[sender][msg.sender];
            require(curAllowance >= amount, "Insufficient Allowance");
            _allowances[sender][msg.sender] -= amount;
        }
        return _transferFrom(sender, recipient, amount);
    }


    function _transferFrom(address sender, address recipient, uint256 amount) internal returns (bool) {

        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        // These transfers are always feeless and limitless
        if ( authorizations[sender] || authorizations[recipient] || presaleOrlock[sender] || inSwap) {
            return _basicTransfer(sender, recipient, amount);
        }

        // In any other case, check if trading is open already
        require(tradeBlock == false,"Trading not open yet");
            
        // If limits are enabled we check the max wallet and max tx.
        if (limits){checkLimits(sender, recipient, amount);}

        // Check how much fees are accumulated in the contract, if > threshold, swap
        if(shouldTokenSwap(recipient)){ swapBack();}

        // Charge transaction fees (only swaps) when enabled
        if(feesEnabled){
             amount = (recipient == pair || sender == pair) ? takeFee(sender, recipient, amount) : amount;
        } 

        // Send the remaining tokens, after fee
        _basicTransfer(sender, recipient, amount);

        emit Transfer(sender, recipient, amount);
        return true;
    }

    // In case anyone would send ETH to the contract directly
    // or when, for some reason, autoswap would fail. We 
    // send the contact ETH to the marketing wallet
    function clearStuckWETH(uint256 perc) external authorized {
        uint256 amountWETH = address(this).balance;
        payable(marketingWallet).transfer(amountWETH * perc / 100);
    }

}