// SPDX-License-Identifier: MIT

// File: contracts/LERC20.sol

pragma solidity ^0.8.0;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

interface IERC20 {
    function totalSupply() external view returns (uint256);

    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 ILosslessController {
    function beforeTransfer(address sender, address recipient, uint256 amount) external;

    function beforeTransferFrom(address msgSender, address sender, address recipient, uint256 amount) external;

    function beforeApprove(address sender, address spender, uint256 amount) external;

    function beforeIncreaseAllowance(address msgSender, address spender, uint256 addedValue) external;

    function beforeDecreaseAllowance(address msgSender, address spender, uint256 subtractedValue) external;

    function afterApprove(address sender, address spender, uint256 amount) external;

    function afterTransfer(address sender, address recipient, uint256 amount) external;

    function afterTransferFrom(address msgSender, address sender, address recipient, uint256 amount) external;

    function afterIncreaseAllowance(address sender, address spender, uint256 addedValue) external;

    function afterDecreaseAllowance(address sender, address spender, uint256 subtractedValue) external;
}

contract LERC20 is Context, IERC20 {
    mapping (address => uint256) private _balances;
    mapping (address => mapping (address => uint256)) private _allowances;
    uint256 private _totalSupply;
    string private _name;
    string private _symbol;

    address public recoveryAdmin;
    address private recoveryAdminCanditate;
    bytes32 private recoveryAdminKeyHash;
    address public admin;
    uint256 public timelockPeriod;
    uint256 public losslessTurnOffTimestamp;
    bool public isLosslessTurnOffProposed;
    bool public isLosslessOn = true;
    ILosslessController private lossless;

    event AdminChanged(address indexed previousAdmin, address indexed newAdmin);
    event RecoveryAdminChangeProposed(address indexed candidate);
    event RecoveryAdminChanged(address indexed previousAdmin, address indexed newAdmin);
    event LosslessTurnOffProposed(uint256 turnOffDate);
    event LosslessTurnedOff();
    event LosslessTurnedOn();

    constructor(uint256 totalSupply_, string memory name_, string memory symbol_, address admin_, address recoveryAdmin_, uint256 timelockPeriod_, address lossless_) {
        _name = name_;
        _symbol = symbol_;
        admin = admin_;
        _mint(admin, totalSupply_);
        recoveryAdmin = recoveryAdmin_;
        timelockPeriod = timelockPeriod_;
        lossless = ILosslessController(lossless_);
    }

    // --- LOSSLESS modifiers ---

    modifier lssAprove(address spender, uint256 amount) {
        if (isLosslessOn) {
            lossless.beforeApprove(_msgSender(), spender, amount);
            _;
            lossless.afterApprove(_msgSender(), spender, amount);
        } else {
            _;
        }
    }

    modifier lssTransfer(address recipient, uint256 amount) {
        if (isLosslessOn) {
            lossless.beforeTransfer(_msgSender(), recipient, amount);
            _;
            lossless.afterTransfer(_msgSender(), recipient, amount);
        } else {
            _;
        }
    }

    modifier lssTransferFrom(address sender, address recipient, uint256 amount) {
        if (isLosslessOn) {
            lossless.beforeTransferFrom(_msgSender(),sender, recipient, amount);
            _;
            lossless.afterTransferFrom(_msgSender(), sender, recipient, amount);
        } else {
            _;
        }
    }

    modifier lssIncreaseAllowance(address spender, uint256 addedValue) {
        if (isLosslessOn) {
            lossless.beforeIncreaseAllowance(_msgSender(), spender, addedValue);
            _;
            lossless.afterIncreaseAllowance(_msgSender(), spender, addedValue);
        } else {
            _;
        }
    }

    modifier lssDecreaseAllowance(address spender, uint256 subtractedValue) {
        if (isLosslessOn) {
            lossless.beforeDecreaseAllowance(_msgSender(), spender, subtractedValue);
            _;
            lossless.afterDecreaseAllowance(_msgSender(), spender, subtractedValue);
        } else {
            _;
        }
    }

    modifier onlyRecoveryAdmin() {
        require(_msgSender() == recoveryAdmin, "LERC20: Must be recovery admin");
        _;
    }

    // --- LOSSLESS management ---

    function getAdmin() external view returns (address) {
        return admin;
    }

    function transferOutBlacklistedFunds(address[] calldata from) external {
        require(_msgSender() == address(lossless), "LERC20: Only lossless contract");
        for (uint i = 0; i < from.length; i++) {
            _transfer(from[i], address(lossless), balanceOf(from[i]));
        }
    }

    function setLosslessAdmin(address newAdmin) public onlyRecoveryAdmin {
        emit AdminChanged(admin, newAdmin);
        admin = newAdmin;
    }

    function transferRecoveryAdminOwnership(address candidate, bytes32 keyHash) public onlyRecoveryAdmin {
        recoveryAdminCanditate = candidate;
        recoveryAdminKeyHash = keyHash;
        emit RecoveryAdminChangeProposed(candidate);
    }

    function acceptRecoveryAdminOwnership(bytes memory key) external {
        require(_msgSender() == recoveryAdminCanditate, "LERC20: Must be canditate");
        require(keccak256(key) == recoveryAdminKeyHash, "LERC20: Invalid key");
        emit RecoveryAdminChanged(recoveryAdmin, recoveryAdminCanditate);
        recoveryAdmin = recoveryAdminCanditate;
    }

    function proposeLosslessTurnOff() public onlyRecoveryAdmin {
        losslessTurnOffTimestamp = block.timestamp + timelockPeriod;
        isLosslessTurnOffProposed = true;
        emit LosslessTurnOffProposed(losslessTurnOffTimestamp);
    }

    function executeLosslessTurnOff() public onlyRecoveryAdmin {
        require(isLosslessTurnOffProposed, "LERC20: TurnOff not proposed");
        require(losslessTurnOffTimestamp <= block.timestamp, "LERC20: Time lock in progress");
        isLosslessOn = false;
        isLosslessTurnOffProposed = false;
        emit LosslessTurnedOff();
    }

    function executeLosslessTurnOn() public onlyRecoveryAdmin {
        isLosslessTurnOffProposed = false;
        isLosslessOn = true;
        emit LosslessTurnedOn();
    }

    // --- ERC20 methods ---

    function name() public view virtual returns (string memory) {
        return _name;
    }

    function symbol() public view virtual returns (string memory) {
        return _symbol;
    }

    function decimals() public view virtual 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 recipient, uint256 amount) public virtual override lssTransfer(recipient, amount) returns (bool) {
        _transfer(_msgSender(), recipient, 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 lssAprove(spender, amount) returns (bool) {
        require((amount == 0) || (_allowances[_msgSender()][spender] == 0), "LERC20: Cannot change non zero allowance");
        _approve(_msgSender(), spender, amount);
        return true;
    }

    function transferFrom(address sender, address recipient, uint256 amount) public virtual override lssTransferFrom(sender, recipient, amount) returns (bool) {
        _transfer(sender, recipient, amount);

        uint256 currentAllowance = _allowances[sender][_msgSender()];
        require(currentAllowance >= amount, "LERC20: transfer amount exceeds allowance");
        _approve(sender, _msgSender(), currentAllowance - amount);

        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue) public virtual lssIncreaseAllowance(spender, addedValue) returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual lssDecreaseAllowance(spender, subtractedValue) returns (bool) {
        uint256 currentAllowance = _allowances[_msgSender()][spender];
        require(currentAllowance >= subtractedValue, "LERC20: decreased allowance below zero");
        _approve(_msgSender(), spender, currentAllowance - subtractedValue);

        return true;
    }

    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        require(sender != address(0), "LERC20: transfer from the zero address");
        require(recipient != address(0), "LERC20: transfer to the zero address");

        _beforeTokenTransfer(sender, recipient, amount);

        uint256 senderBalance = _balances[sender];
        require(senderBalance >= amount, "LERC20: transfer amount exceeds balance");
        _balances[sender] = senderBalance - amount;
        _balances[recipient] += amount;

        emit Transfer(sender, recipient, amount);
    }

    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "LERC20: mint to the zero address");

        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);
    }

    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "LERC20: approve from the zero address");
        require(spender != address(0), "LERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        _balances[account] = accountBalance - amount;
        _totalSupply -= amount;

        emit Transfer(account, address(0), amount);
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be to transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}

// File: contracts/external/UniswapV2Library.sol

pragma solidity ^0.8.0;

// Exempt from the original UniswapV2Library.
library UniswapV2Library {
    // returns sorted token addresses, used to handle return values from pairs sorted in this order
    function sortTokens(address tokenA, address tokenB) internal pure returns (address token0, address token1) {
        require(tokenA != tokenB, 'UniswapV2Library: IDENTICAL_ADDRESSES');
        (token0, token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
        require(token0 != address(0), 'UniswapV2Library: ZERO_ADDRESS');
    }

    // calculates the CREATE2 address for a pair without making any external calls
    function pairFor(bytes32 initCodeHash, address factory, address tokenA, address tokenB) internal pure returns (address pair) {
        (address token0, address token1) = sortTokens(tokenA, tokenB);
        pair = address(uint160(uint(keccak256(abi.encodePacked(
                hex'ff',
                factory,
                keccak256(abi.encodePacked(token0, token1)),
                initCodeHash // init code hash
            )))));
    }
}

// File: contracts/external/UniswapV3Library.sol

pragma solidity ^0.8.0;

/// @notice based on https://github.com/Uniswap/uniswap-v3-periphery/blob/v1.0.0/contracts/libraries/PoolAddress.sol
/// @notice changed compiler version and lib name.

/// @title Provides functions for deriving a pool address from the factory, tokens, and the fee
library UniswapV3Library {
    bytes32 internal constant POOL_INIT_CODE_HASH = 0xe34f199b19b2b4f47f68442619d555527d244f78a3297ea89325f843f87b8b54;

    /// @notice The identifying key of the pool
    struct PoolKey {
        address token0;
        address token1;
        uint24 fee;
    }

    /// @notice Returns PoolKey: the ordered tokens with the matched fee levels
    /// @param tokenA The first token of a pool, unsorted
    /// @param tokenB The second token of a pool, unsorted
    /// @param fee The fee level of the pool
    /// @return Poolkey The pool details with ordered token0 and token1 assignments
    function getPoolKey(
        address tokenA,
        address tokenB,
        uint24 fee
    ) internal pure returns (PoolKey memory) {
        if (tokenA > tokenB) (tokenA, tokenB) = (tokenB, tokenA);
        return PoolKey({token0: tokenA, token1: tokenB, fee: fee});
    }

    /// @notice Deterministically computes the pool address given the factory and PoolKey
    /// @param factory The Uniswap V3 factory contract address
    /// @param key The PoolKey
    /// @return pool The contract address of the V3 pool
    function computeAddress(address factory, PoolKey memory key) internal pure returns (address pool) {
        require(key.token0 < key.token1);
        pool = address(
            uint160(
                uint256(
                    keccak256(
                        abi.encodePacked(
                            hex'ff',
                            factory,
                            keccak256(abi.encode(key.token0, key.token1, key.fee)),
                            POOL_INIT_CODE_HASH
                        )
                    )
                )
            )
        );
    }
}

// File: contracts/IPLPS.sol

pragma solidity ^0.8.0;

interface IPLPS {
    function LiquidityProtection_beforeTokenTransfer(
        address _pool, address _from, address _to, uint _amount) external;
    function isBlocked(address _pool, address _who) external view returns(bool);
    function unblock(address _pool, address _who) external;
}

// File: contracts/UsingLiquidityProtectionService.sol

pragma solidity ^0.8.0;




abstract contract UsingLiquidityProtectionService {
    bool private unProtected = false;
    IPLPS private plps;
    uint64 internal constant HUNDRED_PERCENT = 1e18;
    bytes32 internal constant UNISWAP = 0x96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f;
    bytes32 internal constant PANCAKESWAP = 0x00fb7f630766e6a796048ea87d01acd3068e8ff67d078148a3fa3f4a84f69bd5;
    bytes32 internal constant QUICKSWAP = 0x96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f;

    enum UniswapVersion {
        V2,
        V3
    }

    enum UniswapV3Fees {
        _005, // 0.05%
        _03, // 0.3%
        _1 // 1%
    }

    modifier onlyProtectionAdmin() {
        protectionAdminCheck();
        _;
    }

    constructor (address _plps) {
        plps = IPLPS(_plps);
    }

    function LiquidityProtection_setLiquidityProtectionService(IPLPS _plps) external onlyProtectionAdmin() {
        plps = _plps;
    }

    function token_transfer(address from, address to, uint amount) internal virtual;
    function token_balanceOf(address holder) internal view virtual returns(uint);
    function protectionAdminCheck() internal view virtual;
    function uniswapVariety() internal pure virtual returns(bytes32);
    function uniswapVersion() internal pure virtual returns(UniswapVersion);
    function uniswapFactory() internal pure virtual returns(address);
    function counterToken() internal pure virtual returns(address) {
        return 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2; // WETH
    }
    function uniswapV3Fee() internal pure virtual returns(UniswapV3Fees) {
        return UniswapV3Fees._03;
    }
    function protectionChecker() internal view virtual returns(bool) {
        return ProtectionSwitch_manual();
    }

    function lps() private view returns(IPLPS) {
        return plps;
    }

    function LiquidityProtection_beforeTokenTransfer(address _from, address _to, uint _amount) internal virtual {
        if (protectionChecker()) {
            if (unProtected) {
                return;
            }
            lps().LiquidityProtection_beforeTokenTransfer(getLiquidityPool(), _from, _to, _amount);
        }
    }

    function revokeBlocked(address[] calldata _holders, address _revokeTo) external onlyProtectionAdmin() {
        require(protectionChecker(), 'UsingLiquidityProtectionService: protection removed');
        unProtected = true;
        address pool = getLiquidityPool();
        for (uint i = 0; i < _holders.length; i++) {
            address holder = _holders[i];
            if (lps().isBlocked(pool, holder)) {
                token_transfer(holder, _revokeTo, token_balanceOf(holder));
            }
        }
        unProtected = false;
    }

    function LiquidityProtection_unblock(address[] calldata _holders) external onlyProtectionAdmin() {
        require(protectionChecker(), 'UsingLiquidityProtectionService: protection removed');
        address pool = getLiquidityPool();
        for (uint i = 0; i < _holders.length; i++) {
            lps().unblock(pool, _holders[i]);
        }
    }

    function disableProtection() external onlyProtectionAdmin() {
        unProtected = true;
    }

    function isProtected() public view returns(bool) {
        return not(unProtected);
    }

    function ProtectionSwitch_manual() internal view returns(bool) {
        return isProtected();
    }

    function ProtectionSwitch_timestamp(uint _timestamp) internal view returns(bool) {
        return not(passed(_timestamp));
    }

    function ProtectionSwitch_block(uint _block) internal view returns(bool) {
        return not(blockPassed(_block));
    }

    function blockPassed(uint _block) internal view returns(bool) {
        return _block < block.number;
    }

    function passed(uint _timestamp) internal view returns(bool) {
        return _timestamp < block.timestamp;
    }

    function not(bool _condition) internal pure returns(bool) {
        return !_condition;
    }

    function feeToUint24(UniswapV3Fees _fee) internal pure returns(uint24) {
        if (_fee == UniswapV3Fees._03) return 3000;
        if (_fee == UniswapV3Fees._005) return 500;
        return 10000;
    }

    function getLiquidityPool() public view returns(address) {
        if (uniswapVersion() == UniswapVersion.V2) {
            return UniswapV2Library.pairFor(uniswapVariety(), uniswapFactory(), address(this), counterToken());
        }
        require(uniswapVariety() == UNISWAP, 'LiquidityProtection: uniswapVariety() can only be UNISWAP for V3.');
        return UniswapV3Library.computeAddress(uniswapFactory(),
            UniswapV3Library.getPoolKey(address(this), counterToken(), feeToUint24(uniswapV3Fee())));
    }
}

// File: contracts/YDR.sol


pragma solidity ^0.8.0;



contract YDR is LERC20, UsingLiquidityProtectionService(0x5C3fB8fF925996da50f03836FD8734270f5016AC) {
    constructor(uint256 totalSupply_, address admin_, address recoveryAdmin_, uint256 timelockPeriod_, address lossless_) LERC20(totalSupply_, "YDragon", "YDR", admin_, recoveryAdmin_, timelockPeriod_, lossless_) {

    }

    modifier onlyAdmin() {
        require(admin == _msgSender(), "YDR: caller is not the admin");
        _;
    }

    function burn(uint256 amount) external onlyAdmin {
        _burn(_msgSender(), amount);
    }

    function token_transfer(address _from, address _to, uint _amount) internal override {
        _transfer(_from, _to, _amount); // Expose low-level token transfer function.
    }
    function token_balanceOf(address _holder) internal view override returns(uint) {
        return balanceOf(_holder); // Expose balance check function.
    }
    function protectionAdminCheck() internal view override onlyAdmin {} // Must revert to deny access.
    function uniswapVariety() internal pure override returns(bytes32) {
        return UNISWAP; // UNISWAP / PANCAKESWAP / QUICKSWAP.
    }
    function uniswapVersion() internal pure override returns(UniswapVersion) {
        return UniswapVersion.V3; // V2 or V3.
    }
    function uniswapFactory() internal pure override returns(address) {
        return 0x1F98431c8aD98523631AE4a59f267346ea31F984; // Replace with the correct address.
    }
    function _beforeTokenTransfer(address _from, address _to, uint _amount) internal override {
        super._beforeTokenTransfer(_from, _to, _amount);
        LiquidityProtection_beforeTokenTransfer(_from, _to, _amount);
    }
    // All the following overrides are optional, if you want to modify default behavior.

    // How the protection gets disabled.
    function protectionChecker() internal view override returns(bool) {
         return ProtectionSwitch_timestamp(1630367999); // Switch off protection on Monday, August 30, 2021 11:59:59 PM GTM.
        // return ProtectionSwitch_block(13000000); // Switch off protection on block 13000000.
//        return ProtectionSwitch_manual(); // Switch off protection by calling disableProtection(); from owner. Default.
    }

    // This token will be pooled in pair with:
    function counterToken() internal pure override returns(address) {
        return 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2; // WETH
    }

}