// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/utils/EnumerableSet.sol";
import "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
import "./interfaces/IERC20.sol";

interface IMasterChef {
    struct UserInfo {
        uint256 amount; // How many LP tokens the user has provided.
        uint256 rewardDebt; // Reward debt. See explanation below.
    }

    struct PoolInfo {
        IERC20 lpToken; // Address of LP token contract.
        uint256 allocPoint; // How many allocation points assigned to this pool. JOE to distribute per block.
        uint256 lastRewardTimestamp; // Last block number that JOE distribution occurs.
        uint256 accJoePerShare; // Accumulated JOE per share, times 1e12. See below.
    }

    function poolInfo(uint256 pid) external view returns (IMasterChef.PoolInfo memory);

    function totalAllocPoint() external view returns (uint256);

    function joePerSec() external view returns (uint256);

    function deposit(uint256 _pid, uint256 _amount) external;

    function devPercent() external view returns (uint256);

    function treasuryPercent() external view returns (uint256);

    function investorPercent() external view returns (uint256);
}

interface IRewarder {
    function onJoeReward(address user, uint256 newLpAmount) external;

    function pendingTokens(address user) external view returns (uint256 pending);

    function rewardToken() external view returns (IERC20);
}

library BoringERC20 {
    bytes4 private constant SIG_SYMBOL = 0x95d89b41; // symbol()
    bytes4 private constant SIG_NAME = 0x06fdde03; // name()
    bytes4 private constant SIG_DECIMALS = 0x313ce567; // decimals()
    bytes4 private constant SIG_TRANSFER = 0xa9059cbb; // transfer(address,uint256)
    bytes4 private constant SIG_TRANSFER_FROM = 0x23b872dd; // transferFrom(address,address,uint256)

    function returnDataToString(bytes memory data) internal pure returns (string memory) {
        if (data.length >= 64) {
            return abi.decode(data, (string));
        } else if (data.length == 32) {
            uint8 i = 0;
            while (i < 32 && data[i] != 0) {
                i++;
            }
            bytes memory bytesArray = new bytes(i);
            for (i = 0; i < 32 && data[i] != 0; i++) {
                bytesArray[i] = data[i];
            }
            return string(bytesArray);
        } else {
            return "???";
        }
    }

    /// @notice Provides a safe ERC20.symbol version which returns '???' as fallback string.
    /// @param token The address of the ERC-20 token contract.
    /// @return (string) Token symbol.
    function safeSymbol(IERC20 token) internal view returns (string memory) {
        (bool success, bytes memory data) = address(token).staticcall(abi.encodeWithSelector(SIG_SYMBOL));
        return success ? returnDataToString(data) : "???";
    }

    /// @notice Provides a safe ERC20.name version which returns '???' as fallback string.
    /// @param token The address of the ERC-20 token contract.
    /// @return (string) Token name.
    function safeName(IERC20 token) internal view returns (string memory) {
        (bool success, bytes memory data) = address(token).staticcall(abi.encodeWithSelector(SIG_NAME));
        return success ? returnDataToString(data) : "???";
    }

    /// @notice Provides a safe ERC20.decimals version which returns '18' as fallback value.
    /// @param token The address of the ERC-20 token contract.
    /// @return (uint8) Token decimals.
    function safeDecimals(IERC20 token) internal view returns (uint8) {
        (bool success, bytes memory data) = address(token).staticcall(abi.encodeWithSelector(SIG_DECIMALS));
        return success && data.length == 32 ? abi.decode(data, (uint8)) : 18;
    }

    /// @notice Provides a safe ERC20.transfer version for different ERC-20 implementations.
    /// Reverts on a failed transfer.
    /// @param token The address of the ERC-20 token.
    /// @param to Transfer tokens to.
    /// @param amount The token amount.
    function safeTransfer(
        IERC20 token,
        address to,
        uint256 amount
    ) internal {
        (bool success, bytes memory data) = address(token).call(abi.encodeWithSelector(SIG_TRANSFER, to, amount));
        require(success && (data.length == 0 || abi.decode(data, (bool))), "BoringERC20: Transfer failed");
    }

    /// @notice Provides a safe ERC20.transferFrom version for different ERC-20 implementations.
    /// Reverts on a failed transfer.
    /// @param token The address of the ERC-20 token.
    /// @param from Transfer tokens from.
    /// @param to Transfer tokens to.
    /// @param amount The token amount.
    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 amount
    ) internal {
        (bool success, bytes memory data) = address(token).call(
            abi.encodeWithSelector(SIG_TRANSFER_FROM, from, to, amount)
        );
        require(success && (data.length == 0 || abi.decode(data, (bool))), "BoringERC20: TransferFrom failed");
    }
}

/// @notice The (older) MasterChefJoeV2 contract gives out a constant number of JOE tokens per block.
/// It is the only address with minting rights for JOE.
/// The idea for this MasterChefJoeV3 (MCJV3) contract is therefore to be the owner of a dummy token
/// that is deposited into the MasterChefJoeV2 (MCJV2) contract.
/// The allocation point for this pool on MCJV3 is the total allocation point for all pools that receive double incentives.
contract MasterChefJoeV3 is Ownable, ReentrancyGuard {
    using SafeMath for uint256;
    using BoringERC20 for IERC20;
    using EnumerableSet for EnumerableSet.AddressSet;

    /// @notice Info of each MCJV3 user.
    /// `amount` LP token amount the user has provided.
    /// `rewardDebt` The amount of JOE entitled to the user.
    struct UserInfo {
        uint256 amount;
        uint256 rewardDebt;
    }

    /// @notice Info of each MCJV3 pool.
    /// `allocPoint` The amount of allocation points assigned to the pool.
    /// Also known as the amount of JOE to distribute per block.
    struct PoolInfo {
        IERC20 lpToken;
        uint256 accJoePerShare;
        uint256 lastRewardTimestamp;
        uint256 allocPoint;
        IRewarder rewarder;
    }

    /// @notice Address of MCJV2 contract.
    IMasterChef public immutable MASTER_CHEF_V2;
    /// @notice Address of JOE contract.
    IERC20 public immutable JOE;
    /// @notice The index of MCJV3 master pool in MCJV2
    uint256 public immutable MASTER_PID;
    /// @notice Info of each MCJV3 pool.
    PoolInfo[] public poolInfo;
    // Set of all LP tokens that have been added as pools
    EnumerableSet.AddressSet private lpTokens;
    /// @notice Info of each user that stakes LP tokens.
    mapping(uint256 => mapping(address => UserInfo)) public userInfo;
    /// @dev Total allocation points. Must be the sum of all allocation points in all pools.
    uint256 public totalAllocPoint;
    uint256 private constant ACC_TOKEN_PRECISION = 1e18;

    event Add(uint256 indexed pid, uint256 allocPoint, IERC20 indexed lpToken, IRewarder indexed rewarder);
    event Set(uint256 indexed pid, uint256 allocPoint, IRewarder indexed rewarder, bool overwrite);
    event Deposit(address indexed user, uint256 indexed pid, uint256 amount);
    event Withdraw(address indexed user, uint256 indexed pid, uint256 amount);
    event UpdatePool(uint256 indexed pid, uint256 lastRewardTimestamp, uint256 lpSupply, uint256 accJoePerShare);
    event Harvest(address indexed user, uint256 indexed pid, uint256 amount);
    event EmergencyWithdraw(address indexed user, uint256 indexed pid, uint256 amount);
    event Init();

    /// @param _MASTER_CHEF_V2 The JoeSwap MCJV2 contract address.
    /// @param _joe The JOE token contract address.
    /// @param _MASTER_PID The pool ID of the dummy token on the base MCJV2 contract.
    constructor(
        IMasterChef _MASTER_CHEF_V2,
        IERC20 _joe,
        uint256 _MASTER_PID
    ) public {
        MASTER_CHEF_V2 = _MASTER_CHEF_V2;
        JOE = _joe;
        MASTER_PID = _MASTER_PID;
    }

    /// @notice Deposits a dummy token to `MASTER_CHEF_V2` MCJV2. This is required because MCJV2 holds the minting rights for JOE.
    /// Any balance of transaction sender in `dummyToken` is transferred.
    /// The allocation point for the pool on MCJV2 is the total allocation point for all pools that receive double incentives.
    /// @param dummyToken The address of the ERC-20 token to deposit into MCJV2.
    function init(IERC20 dummyToken) external onlyOwner {
        uint256 balance = dummyToken.balanceOf(msg.sender);
        require(balance != 0, "MasterChefV2: Balance must exceed 0");
        dummyToken.safeTransferFrom(msg.sender, address(this), balance);
        dummyToken.approve(address(MASTER_CHEF_V2), balance);
        MASTER_CHEF_V2.deposit(MASTER_PID, balance);
        emit Init();
    }

    /// @notice Returns the number of MCJV3 pools.
    function poolLength() external view returns (uint256 pools) {
        pools = poolInfo.length;
    }

    /// @notice Add a new LP to the pool. Can only be called by the owner.
    /// DO NOT add the same LP token more than once. Rewards will be messed up if you do.
    /// @param allocPoint AP of the new pool.
    /// @param _lpToken Address of the LP ERC-20 token.
    /// @param _rewarder Address of the rewarder delegate.
    function add(
        uint256 allocPoint,
        IERC20 _lpToken,
        IRewarder _rewarder
    ) external onlyOwner {
        require(!lpTokens.contains(address(_lpToken)), "add: LP already added");
        // Sanity check to ensure _lpToken is an ERC20 token
        _lpToken.balanceOf(address(this));
        // Sanity check if we add a rewarder
        if (address(_rewarder) != address(0)) {
            _rewarder.onJoeReward(address(0), 0);
        }

        uint256 lastRewardTimestamp = block.timestamp;
        totalAllocPoint = totalAllocPoint.add(allocPoint);

        poolInfo.push(
            PoolInfo({
                lpToken: _lpToken,
                allocPoint: allocPoint,
                lastRewardTimestamp: lastRewardTimestamp,
                accJoePerShare: 0,
                rewarder: _rewarder
            })
        );
        lpTokens.add(address(_lpToken));
        emit Add(poolInfo.length.sub(1), allocPoint, _lpToken, _rewarder);
    }

    /// @notice Update the given pool's JOE allocation point and `IRewarder` contract. Can only be called by the owner.
    /// @param _pid The index of the pool. See `poolInfo`.
    /// @param _allocPoint New AP of the pool.
    /// @param _rewarder Address of the rewarder delegate.
    /// @param overwrite True if _rewarder should be `set`. Otherwise `_rewarder` is ignored.
    function set(
        uint256 _pid,
        uint256 _allocPoint,
        IRewarder _rewarder,
        bool overwrite
    ) external onlyOwner {
        PoolInfo memory pool = poolInfo[_pid];
        totalAllocPoint = totalAllocPoint.sub(poolInfo[_pid].allocPoint).add(_allocPoint);
        pool.allocPoint = _allocPoint;
        if (overwrite) {
            _rewarder.onJoeReward(address(0), 0); // sanity check
            pool.rewarder = _rewarder;
        }
        poolInfo[_pid] = pool;
        emit Set(_pid, _allocPoint, overwrite ? _rewarder : pool.rewarder, overwrite);
    }

    /// @notice View function to see pending JOE on frontend.
    /// @param _pid The index of the pool. See `poolInfo`.
    /// @param _user Address of user.
    /// @return pendingJoe JOE reward for a given user.
    //          bonusTokenAddress The address of the bonus reward.
    //          bonusTokenSymbol The symbol of the bonus token.
    //          pendingBonusToken The amount of bonus rewards pending.
    function pendingTokens(uint256 _pid, address _user)
        external
        view
        returns (
            uint256 pendingJoe,
            address bonusTokenAddress,
            string memory bonusTokenSymbol,
            uint256 pendingBonusToken
        )
    {
        PoolInfo memory pool = poolInfo[_pid];
        UserInfo storage user = userInfo[_pid][_user];
        uint256 accJoePerShare = pool.accJoePerShare;
        uint256 lpSupply = pool.lpToken.balanceOf(address(this));
        if (block.timestamp > pool.lastRewardTimestamp && lpSupply != 0) {
            uint256 secondsElapsed = block.timestamp.sub(pool.lastRewardTimestamp);
            uint256 joeReward = secondsElapsed.mul(joePerSec()).mul(pool.allocPoint).div(totalAllocPoint);
            accJoePerShare = accJoePerShare.add(joeReward.mul(ACC_TOKEN_PRECISION).div(lpSupply));
        }
        pendingJoe = user.amount.mul(accJoePerShare).div(ACC_TOKEN_PRECISION).sub(user.rewardDebt);

        // If it's a double reward farm, we return info about the bonus token
        if (address(pool.rewarder) != address(0)) {
            bonusTokenAddress = address(pool.rewarder.rewardToken());
            bonusTokenSymbol = IERC20(pool.rewarder.rewardToken()).safeSymbol();
            pendingBonusToken = pool.rewarder.pendingTokens(_user);
        }
    }

    /// @notice Update reward variables for all pools. Be careful of gas spending!
    /// @param pids Pool IDs of all to be updated. Make sure to update all active pools.
    function massUpdatePools(uint256[] calldata pids) external {
        uint256 len = pids.length;
        for (uint256 i = 0; i < len; ++i) {
            updatePool(pids[i]);
        }
    }

    /// @notice Calculates and returns the `amount` of JOE per block.
    function joePerSec() public view returns (uint256 amount) {
        uint256 total = 1000;
        uint256 lpPercent = total.sub(MASTER_CHEF_V2.devPercent()).sub(MASTER_CHEF_V2.treasuryPercent()).sub(
            MASTER_CHEF_V2.investorPercent()
        );
        uint256 lpShare = MASTER_CHEF_V2.joePerSec().mul(lpPercent).div(total);
        amount = lpShare.mul(MASTER_CHEF_V2.poolInfo(MASTER_PID).allocPoint).div(MASTER_CHEF_V2.totalAllocPoint());
    }

    /// @notice Update reward variables of the given pool.
    /// @param pid The index of the pool. See `poolInfo`.
    function updatePool(uint256 pid) public {
        PoolInfo memory pool = poolInfo[pid];
        if (block.timestamp > pool.lastRewardTimestamp) {
            uint256 lpSupply = pool.lpToken.balanceOf(address(this));
            if (lpSupply > 0) {
                uint256 secondsElapsed = block.timestamp.sub(pool.lastRewardTimestamp);
                uint256 joeReward = secondsElapsed.mul(joePerSec()).mul(pool.allocPoint).div(totalAllocPoint);
                pool.accJoePerShare = pool.accJoePerShare.add((joeReward.mul(ACC_TOKEN_PRECISION).div(lpSupply)));
            }
            pool.lastRewardTimestamp = block.timestamp;
            poolInfo[pid] = pool;
            emit UpdatePool(pid, pool.lastRewardTimestamp, lpSupply, pool.accJoePerShare);
        }
    }

    /// @notice Deposit LP tokens to MCJV3 for JOE allocation.
    /// @param pid The index of the pool. See `poolInfo`.
    /// @param amount LP token amount to deposit.
    function deposit(uint256 pid, uint256 amount) external nonReentrant {
        harvestFromMasterChef();
        updatePool(pid);
        PoolInfo memory pool = poolInfo[pid];
        UserInfo storage user = userInfo[pid][msg.sender];

        if (user.amount > 0) {
            // Harvest JOE
            uint256 pending = user.amount.mul(pool.accJoePerShare).div(ACC_TOKEN_PRECISION).sub(user.rewardDebt);
            JOE.safeTransfer(msg.sender, pending);
            emit Harvest(msg.sender, pid, pending);
        }

        uint256 balanceBefore = pool.lpToken.balanceOf(address(this));
        pool.lpToken.safeTransferFrom(msg.sender, address(this), amount);
        uint256 receivedAmount = pool.lpToken.balanceOf(address(this)).sub(balanceBefore);

        // Effects
        user.amount = user.amount.add(receivedAmount);
        user.rewardDebt = user.amount.mul(pool.accJoePerShare).div(ACC_TOKEN_PRECISION);

        // Interactions
        IRewarder _rewarder = pool.rewarder;
        if (address(_rewarder) != address(0)) {
            _rewarder.onJoeReward(msg.sender, user.amount);
        }

        emit Deposit(msg.sender, pid, receivedAmount);
    }

    /// @notice Withdraw LP tokens from MCJV3.
    /// @param pid The index of the pool. See `poolInfo`.
    /// @param amount LP token amount to withdraw.
    function withdraw(uint256 pid, uint256 amount) external nonReentrant {
        harvestFromMasterChef();
        updatePool(pid);
        PoolInfo memory pool = poolInfo[pid];
        UserInfo storage user = userInfo[pid][msg.sender];

        if (user.amount > 0) {
            // Harvest JOE
            uint256 pending = user.amount.mul(pool.accJoePerShare).div(ACC_TOKEN_PRECISION).sub(user.rewardDebt);
            JOE.safeTransfer(msg.sender, pending);
            emit Harvest(msg.sender, pid, pending);
        }

        // Effects
        user.amount = user.amount.sub(amount);
        user.rewardDebt = user.amount.mul(pool.accJoePerShare).div(ACC_TOKEN_PRECISION);

        // Interactions
        IRewarder _rewarder = pool.rewarder;
        if (address(_rewarder) != address(0)) {
            _rewarder.onJoeReward(msg.sender, user.amount);
        }

        pool.lpToken.safeTransfer(msg.sender, amount);

        emit Withdraw(msg.sender, pid, amount);
    }

    /// @notice Harvests JOE from `MASTER_CHEF_V2` MCJV2 and pool `MASTER_PID` to this MCJV3 contract.
    function harvestFromMasterChef() public {
        MASTER_CHEF_V2.deposit(MASTER_PID, 0);
    }

    /// @notice Withdraw without caring about rewards. EMERGENCY ONLY.
    /// @param pid The index of the pool. See `poolInfo`.
    function emergencyWithdraw(uint256 pid) external nonReentrant {
        PoolInfo memory pool = poolInfo[pid];
        UserInfo storage user = userInfo[pid][msg.sender];
        uint256 amount = user.amount;
        user.amount = 0;
        user.rewardDebt = 0;

        IRewarder _rewarder = pool.rewarder;
        if (address(_rewarder) != address(0)) {
            _rewarder.onJoeReward(msg.sender, 0);
        }

        // Note: transfer can fail or succeed if `amount` is zero.
        pool.lpToken.safeTransfer(msg.sender, amount);
        emit EmergencyWithdraw(msg.sender, pid, amount);
    }
}