//SPDX-License-Identifier: MIT

pragma solidity ^0.8.5;

// For calculation.
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) {
// Solidity only automatically asserts when dividing by 0
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;
}
}

// General interface for BEP20 token.
interface IBEP20 {
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);
}

// Make contract can be called by address which is authorized.
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);
}

// Factory interface.
interface IDEXFactory {
function createPair(address tokenA, address tokenB) external returns (address pair);
}

// Router interface.
interface IDEXRouter {
function factory() external pure returns (address);
function WETH() external pure returns (address);

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

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

interface IDividendDistributor {
function setDistributionCriteria(uint256 _minPeriod, uint256 _minDistribution) external;
function setShare(address shareholder, uint256 amount) external;
function deposit() external payable;
function process(uint256 gas) external;
}

contract DividendDistributor is IDividendDistributor {
using SafeMath for uint256;

address _token;

struct Share {
uint256 amount;
uint256 totalExcluded;
uint256 totalRealised;
}

// Token address
IBEP20 SHIB = IBEP20(0x2859e4544C4bB03966803b044A93563Bd2D0DD4D);
address WBNB = 0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c;
IDEXRouter router;

address[] shareholders;
mapping (address => uint256) shareholderIndexes;
mapping (address => uint256) shareholderClaims;

mapping (address => Share) public shares;

uint256 public totalShares;
uint256 public totalDividends;
uint256 public totalDistributed;
uint256 public dividendsPerShare;
uint256 public dividendsPerShareAccuracyFactor = 10 ** 36;

uint256 public minPeriod = 1 hours;
uint256 public minDistribution = 1 * (10 ** 8);

uint256 currentIndex;

bool initialized;
modifier initialization() {
require(!initialized);
_;
initialized = true;
}

modifier onlyToken() {
require(msg.sender == _token); _;
}

// Router
constructor (address _router) {
router = _router != address(0)
? IDEXRouter(_router)
: IDEXRouter(0x10ED43C718714eb63d5aA57B78B54704E256024E);
_token = msg.sender;
}

function setDistributionCriteria(uint256 _minPeriod, uint256 _minDistribution) external override onlyToken {
minPeriod = _minPeriod;
minDistribution = _minDistribution;
}

function setShare(address shareholder, uint256 amount) external override onlyToken {
if(shares[shareholder].amount > 0){
distributeDividend(shareholder);
}

if(amount > 0 && shares[shareholder].amount == 0){
addShareholder(shareholder);
}else if(amount == 0 && shares[shareholder].amount > 0){
removeShareholder(shareholder);
}

totalShares = totalShares.sub(shares[shareholder].amount).add(amount);
shares[shareholder].amount = amount;
shares[shareholder].totalExcluded = getCumulativeDividends(shares[shareholder].amount);
}

function deposit() external payable override onlyToken {
uint256 balanceBefore = SHIB.balanceOf(address(this));

address[] memory path = new address[](2);
path[0] = WBNB;
path[1] = address(SHIB);

router.swapExactETHForTokensSupportingFeeOnTransferTokens{value: msg.value}(
0,
path,
address(this),
block.timestamp
);

uint256 amount = SHIB.balanceOf(address(this)).sub(balanceBefore);

totalDividends = totalDividends.add(amount);
dividendsPerShare = dividendsPerShare.add(dividendsPerShareAccuracyFactor.mul(amount).div(totalShares));
}

function process(uint256 gas) external override onlyToken {
uint256 shareholderCount = shareholders.length;

if(shareholderCount == 0) { return; }

uint256 gasUsed = 0;
uint256 gasLeft = gasleft();

uint256 iterations = 0;

while(gasUsed < gas && iterations < shareholderCount) {
if(currentIndex >= shareholderCount){
currentIndex = 0;
}

if(shouldDistribute(shareholders[currentIndex])){
distributeDividend(shareholders[currentIndex]);
}

gasUsed = gasUsed.add(gasLeft.sub(gasleft()));
gasLeft = gasleft();
currentIndex ;
iterations ;
}
}

function shouldDistribute(address shareholder) internal view returns (bool) {
return shareholderClaims[shareholder] minPeriod < block.timestamp
&& getUnpaidEarnings(shareholder) > minDistribution;
}

function distributeDividend(address shareholder) internal {
if(shares[shareholder].amount == 0){ return; }

uint256 amount = getUnpaidEarnings(shareholder);
if(amount > 0){
totalDistributed = totalDistributed.add(amount);
SHIB.transfer(shareholder, amount);
shareholderClaims[shareholder] = block.timestamp;
shares[shareholder].totalRealised = shares[shareholder].totalRealised.add(amount);
shares[shareholder].totalExcluded = getCumulativeDividends(shares[shareholder].amount);
}
}

function claimDividend(address shareholder) external onlyToken{
distributeDividend(shareholder);
}

function getUnpaidEarnings(address shareholder) public view returns (uint256) {
if(shares[shareholder].amount == 0){ return 0; }

uint256 shareholderTotalDividends = getCumulativeDividends(shares[shareholder].amount);
uint256 shareholderTotalExcluded = shares[shareholder].totalExcluded;

if(shareholderTotalDividends <= shareholderTotalExcluded){ return 0; }

return shareholderTotalDividends.sub(shareholderTotalExcluded);
}

function getCumulativeDividends(uint256 share) internal view returns (uint256) {
return share.mul(dividendsPerShare).div(dividendsPerShareAccuracyFactor);
}

function addShareholder(address shareholder) internal {
shareholderIndexes[shareholder] = shareholders.length;
shareholders.push(shareholder);
}

function removeShareholder(address shareholder) internal {
shareholders[shareholderIndexes[shareholder]] = shareholders[shareholders.length-1];
shareholderIndexes[shareholders[shareholders.length-1]] = shareholderIndexes[shareholder];
shareholders.pop();
}
}

// Main contract
contract SafuuInu is IBEP20, Auth {
using SafeMath for uint256;

// Token address
address SHIB = 0x2859e4544C4bB03966803b044A93563Bd2D0DD4D;
address WBNB = 0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c;
address DEAD = 0x000000000000000000000000000000000000dEaD;
address ZERO = 0x0000000000000000000000000000000000000000;

string constant _name = "Safuu Inu";
string constant _symbol = "SFI";
uint8 constant _decimals = 9;

uint256 _totalSupply = 1_000_000_000 * (10 ** _decimals);
// 1% token supply can be bought each transaction.
uint256 public _maxTxAmount = _totalSupply * 1 / 100;

mapping (address => uint256) _balances;
mapping (address => mapping (address => uint256)) _allowances;

mapping (address => bool) isFeeExempt;
mapping (address => bool) isTxLimitExempt;
mapping (address => bool) isDividendExempt;

uint256 liquidityFee;
uint256 buybackFee;
uint256 reflectionFee;
uint256 marketingFee;
uint256 totalFee;
uint256 feeDenominator;

address _presaler;

address public autoLiquidityReceiver;
address public marketingFeeReceiver;

uint256 targetLiquidity = 25;
uint256 targetLiquidityDenominator = 100;

IDEXRouter public router;
address public pair;

uint256 public launchedAt;

uint256 buybackMultiplierNumerator = 200;
uint256 buybackMultiplierDenominator = 100;
uint256 buybackMultiplierTriggeredAt;
uint256 buybackMultiplierLength = 30 minutes;

bool public autoBuybackEnabled = false;
bool public autoBuybackMultiplier = true;
uint256 autoBuybackCap;
uint256 autoBuybackAccumulator;
uint256 autoBuybackAmount;
uint256 autoBuybackBlockPeriod;
uint256 autoBuybackBlockLast;

DividendDistributor distributor;
uint256 distributorGas = 500000;

bool public swapEnabled = true;
uint256 public swapThreshold = _totalSupply / 500; // 0.2%
bool inSwap;
modifier swapping() { inSwap = true; _; inSwap = false; }

// Router Initial contract
constructor () Auth(msg.sender) {
router = IDEXRouter(0x10ED43C718714eb63d5aA57B78B54704E256024E);
pair = IDEXFactory(router.factory()).createPair(WBNB, address(this));
_allowances[address(this)][address(router)] = type(uint256).max;

distributor = new DividendDistributor(address(router));

// Set fee
liquidityFee = 2;
buybackFee = 0;
reflectionFee = 4;
marketingFee = 4;
totalFee = liquidityFee.add(buybackFee).add(reflectionFee).add(marketingFee);
feeDenominator = 100;

// Presaler. Will update after presale process.
_presaler = msg.sender;
isFeeExempt[_presaler] = true;
isTxLimitExempt[_presaler] = true;
isDividendExempt[pair] = true;
isDividendExempt[address(this)] = true;
isDividendExempt[DEAD] = true;

// Set Liqudity and Marketing receiver
autoLiquidityReceiver = 0x9fa34D5EC305441c0a2F5eE29AcE4cF3cC37c97D;
marketingFeeReceiver = 0xb82bbB43239BA3De45bFb5375EC5F822c32b05aB;

_balances[_presaler] = _totalSupply;
emit Transfer(address(0), _presaler, _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 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); }

checkTxLimit(sender, amount);

if(shouldSwapBack()){ swapBack(); }
if(shouldAutoBuyback()){ triggerAutoBuyback(); }

if(!launched() && recipient == pair){ require(_balances[sender] > 0); launch(); }

_balances[sender] = _balances[sender].sub(amount, "Insufficient Balance");

uint256 amountReceived = shouldTakeFee(sender) ? takeFee(sender, recipient, amount) : amount;
_balances[recipient] = _balances[recipient].add(amountReceived);

if(!isDividendExempt[sender]){ try distributor.setShare(sender, _balances[sender]) {} catch {} }
if(!isDividendExempt[recipient]){ try distributor.setShare(recipient, _balances[recipient]) {} catch {} }

try distributor.process(distributorGas) {} catch {}

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 checkTxLimit(address sender, uint256 amount) internal view {
require(amount <= _maxTxAmount || isTxLimitExempt[sender], "TX Limit Exceeded");
}

function shouldTakeFee(address sender) internal view returns (bool) {
return !isFeeExempt[sender];
}

function getTotalFee(bool selling) public view returns (uint256) {
if(launchedAt 1 >= block.number){ return feeDenominator.sub(1); }
if(selling && buybackMultiplierTriggeredAt.add(buybackMultiplierLength) > block.timestamp){ return getMultipliedFee(); }
return totalFee;
}

function getMultipliedFee() public view returns (uint256) {
uint256 remainingTime = buybackMultiplierTriggeredAt.add(buybackMultiplierLength).sub(block.timestamp);
uint256 feeIncrease = totalFee.mul(buybackMultiplierNumerator).div(buybackMultiplierDenominator).sub(totalFee);
return totalFee.add(feeIncrease.mul(remainingTime).div(buybackMultiplierLength));
}

function takeFee(address sender, address receiver, uint256 amount) internal returns (uint256) {
uint256 feeAmount = amount.mul(getTotalFee(receiver == pair)).div(feeDenominator);

_balances[address(this)] = _balances[address(this)].add(feeAmount);
emit Transfer(sender, address(this), feeAmount);

return amount.sub(feeAmount);
}

function shouldSwapBack() internal view returns (bool) {
return msg.sender != pair
&& !inSwap
&& swapEnabled
&& _balances[address(this)] >= swapThreshold;
}

function swapBack() internal swapping {
uint256 dynamicLiquidityFee = isOverLiquified(targetLiquidity, targetLiquidityDenominator) ? 0 : liquidityFee;
uint256 amountToLiquify = swapThreshold.mul(dynamicLiquidityFee).div(totalFee).div(2);
uint256 amountToSwap = swapThreshold.sub(amountToLiquify);

address[] memory path = new address[](2);
path[0] = address(this);
path[1] = WBNB;

uint256 balanceBefore = address(this).balance;

router.swapExactTokensForETHSupportingFeeOnTransferTokens(
amountToSwap,
0,
path,
address(this),
block.timestamp
);
uint256 amountBNB = address(this).balance.sub(balanceBefore);
uint256 totalBNBFee = totalFee.sub(dynamicLiquidityFee.div(2));
uint256 amountBNBLiquidity = amountBNB.mul(dynamicLiquidityFee).div(totalBNBFee).div(2);
uint256 amountBNBReflection = amountBNB.mul(reflectionFee).div(totalBNBFee);
uint256 amountBNBMarketing = amountBNB.mul(marketingFee).div(totalBNBFee);

try distributor.deposit{value: amountBNBReflection}() {} catch {}
(bool success, /* bytes memory data */) = payable(marketingFeeReceiver).call{value: amountBNBMarketing, gas: 30000}("");
require(success, "receiver rejected ETH transfer");

if(amountToLiquify > 0){
router.addLiquidityETH{value: amountBNBLiquidity}(
address(this),
amountToLiquify,
0,
0,
autoLiquidityReceiver,
block.timestamp
);
emit AutoLiquify(amountBNBLiquidity, amountToLiquify);
}
}

function shouldAutoBuyback() internal view returns (bool) {
return msg.sender != pair
&& !inSwap
&& autoBuybackEnabled
&& autoBuybackBlockLast autoBuybackBlockPeriod <= block.number
&& address(this).balance >= autoBuybackAmount;
}

function triggerManualBuyback(uint256 amount, bool triggerBuybackMultiplier) external authorized {
buyTokens(amount, DEAD);
if(triggerBuybackMultiplier){
buybackMultiplierTriggeredAt = block.timestamp;
emit BuybackMultiplierActive(buybackMultiplierLength);
}
}

function clearBuybackMultiplier() external authorized {
buybackMultiplierTriggeredAt = 0;
}

function triggerAutoBuyback() internal {
buyTokens(autoBuybackAmount, DEAD);
if(autoBuybackMultiplier){
buybackMultiplierTriggeredAt = block.timestamp;
emit BuybackMultiplierActive(buybackMultiplierLength);
}
autoBuybackBlockLast = block.number;
autoBuybackAccumulator = autoBuybackAccumulator.add(autoBuybackAmount);
if(autoBuybackAccumulator > autoBuybackCap){ autoBuybackEnabled = false; }
}

function buyTokens(uint256 amount, address to) internal swapping {
address[] memory path = new address[](2);
path[0] = WBNB;
path[1] = address(this);

router.swapExactETHForTokensSupportingFeeOnTransferTokens{value: amount}(
0,
path,
to,
block.timestamp
);
}

function setAutoBuybackSettings(bool _enabled, uint256 _cap, uint256 _amount, uint256 _period, bool _autoBuybackMultiplier) external authorized {
autoBuybackEnabled = _enabled;
autoBuybackCap = _cap;
autoBuybackAccumulator = 0;
autoBuybackAmount = _amount;
autoBuybackBlockPeriod = _period;
autoBuybackBlockLast = block.number;
autoBuybackMultiplier = _autoBuybackMultiplier;
}

function setBuybackMultiplierSettings(uint256 numerator, uint256 denominator, uint256 length) external authorized {
require(numerator / denominator <= 2 && numerator > denominator);
buybackMultiplierNumerator = numerator;
buybackMultiplierDenominator = denominator;
buybackMultiplierLength = length;
}

function launched() internal view returns (bool) {
return launchedAt != 0;
}

function launch() internal {
launchedAt = block.number;
}

// Tx limit can not be 0 or greater than total supply.
function setTxLimit(uint256 percent) external authorized {
require(percent >= 1 && percent <= 100);
_maxTxAmount = _totalSupply.mul(percent).div(100);
}

function setIsDividendExempt(address holder, bool exempt) external authorized {
require(holder != address(this) && holder != pair);
isDividendExempt[holder] = exempt;
if(exempt){
distributor.setShare(holder, 0);
}else{
distributor.setShare(holder, _balances[holder]);
}
}

function setIsFeeExempt(address holder, bool exempt) external authorized {
isFeeExempt[holder] = exempt;
}

function setIsTxLimitExempt(address holder, bool exempt) external authorized {
isTxLimitExempt[holder] = exempt;
}

// Remove this function to make contract more secure. Fees are fixed when deploy contract.
// function setFees(uint256 _liquidityFee, uint256 _buybackFee, uint256 _reflectionFee, uint256 _marketingFee, uint256 _feeDenominator) external authorized {
// liquidityFee = _liquidityFee;
// buybackFee = _buybackFee;
// reflectionFee = _reflectionFee;
// marketingFee = _marketingFee;
// totalFee = _liquidityFee.add(_buybackFee).add(_reflectionFee).add(_marketingFee);
// feeDenominator = _feeDenominator;
// }

function setFeeReceivers(address _autoLiquidityReceiver, address _marketingFeeReceiver) external authorized {
autoLiquidityReceiver = _autoLiquidityReceiver;
marketingFeeReceiver = _marketingFeeReceiver;
}

function setSwapBackSettings(bool _enabled, uint256 _amount) external authorized {
swapEnabled = _enabled;
swapThreshold = _amount;
}

function setTargetLiquidity(uint256 _target, uint256 _denominator) external authorized {
targetLiquidity = _target;
targetLiquidityDenominator = _denominator;
}

function manualSend() external authorized {
uint256 contractETHBalance = address(this).balance;
payable(marketingFeeReceiver).transfer(contractETHBalance);
}

function setDistributionCriteria(uint256 _minPeriod, uint256 _minDistribution) external authorized {
distributor.setDistributionCriteria(_minPeriod, _minDistribution);
}

function claimDividend() external {
distributor.claimDividend(msg.sender);
}

function getUnpaidEarnings(address shareholder) public view returns (uint256) {
return distributor.getUnpaidEarnings(shareholder);
}

function setDistributorSettings(uint256 gas) external authorized {
require(gas < 750000);
distributorGas = gas;
}

function getCirculatingSupply() public view returns (uint256) {
return _totalSupply.sub(balanceOf(DEAD)).sub(balanceOf(ZERO));
}

function getLiquidityBacking(uint256 accuracy) public view returns (uint256) {
return accuracy.mul(balanceOf(pair).mul(2)).div(getCirculatingSupply());
}

function isOverLiquified(uint256 target, uint256 accuracy) public view returns (bool) {
return getLiquidityBacking(accuracy) > target;
}

function setPresaler(address _newPresalerAddress) external authorized {
_presaler = _newPresalerAddress;
}

event AutoLiquify(uint256 amountBNB, uint256 amountBOG);
event BuybackMultiplierActive(uint256 duration);
}