abstract contract MiningBase is Ownable, Multicall, ReentrancyGuard {

    using SafeERC20 for IERC20;
    using EnumerableSet for EnumerableSet.UintSet;

    /// @dev Last block number that the accRewardRerShare is touched.
    uint256 public lastTouchBlock;

    /// @dev The block number when NFT mining rewards starts/ends.
    uint256 public startBlock;
    uint256 public endBlock;
    struct RewardInfo {
        /// @dev Contract of the reward erc20 token.
        address rewardToken;
        /// @dev who provides reward
        address provider;
        /// @dev Accumulated Reward Tokens per share, times Q128.
        uint256 accRewardPerShare;
        /// @dev Reward amount for each block.
        uint256 rewardPerBlock;
    }

    mapping(uint256 => RewardInfo) public rewardInfos;
    uint256 public rewardInfosLen;

    /// @dev Store the owner of the NFT token
    mapping(uint256 => address) public owners;
    /// @dev The inverse mapping of owners.
    mapping(address => EnumerableSet.UintSet) internal tokenIds;

    /// @dev token to lock, 0 for not boost
    IERC20 public iziToken;
    /// @dev current total nIZI.
    uint256 public totalNIZI;

    /// @notice Current total virtual liquidity.
    uint256 public totalVLiquidity;

    /// @notice emit if user successfully deposit
    /// @param user user
    /// @param tokenId id of mining (same as uniswap nft token id)
    /// @param nIZI amount of boosted iZi
    event Deposit(address indexed user, uint256 tokenId, uint256 nIZI);
    /// @notice emit if user successfully withdraw
    /// @param user user
    /// @param tokenId id of mining (same as uniswap nft token id)
    event Withdraw(address indexed user, uint256 tokenId);
    /// @notice emit if user successfully collect reward
    /// @param user user
    /// @param tokenId id of mining (same as uniswap nft token id)
    /// @param token address of reward erc-20 token
    /// @param amount amount of erc-20 token user received 
    event CollectReward(address indexed user, uint256 tokenId, address token, uint256 amount);
    /// @notice emit if contract owner successfully calls modifyEndBlock(...)
    /// @param endBlock endBlock 
    event ModifyEndBlock(uint256 endBlock);
    /// @notice emit if contract owner successfully calls modifyRewardPerBlock(...)
    /// @param rewardToken address of reward erc20-token
    /// @param rewardPerBlock new reward per block of 'rewardToken'
    event ModifyRewardPerBlock(address indexed rewardToken, uint256 rewardPerBlock);
    /// @notice emit if contract owner successfully calls modifyProvider(...)
    /// @param rewardToken address of reward erc20-token
    /// @param provider New provider
    event ModifyProvider(address indexed rewardToken, address provider);

    /// @notice Update reward variables to be up-to-date.
    /// @param vLiquidity vLiquidity to add or minus
    /// @param isAdd add or minus
    function _updateVLiquidity(uint256 vLiquidity, bool isAdd) internal {
        if (isAdd) {
            totalVLiquidity = totalVLiquidity + vLiquidity;
        } else {
            totalVLiquidity = totalVLiquidity - vLiquidity;
        }

        // max lockBoostMultiplier is 3
        require(totalVLiquidity <= FixedPoints.Q128 * 3, "TOO MUCH LIQUIDITY STAKED");
    }

    /// @notice Update reward variables to be up-to-date.
    /// @param nIZI amount of boosted iZi to add or minus
    /// @param isAdd add or minus
    function _updateNIZI(uint256 nIZI, bool isAdd) internal {
        if (isAdd) {
            totalNIZI = totalNIZI + nIZI;
        } else {
            totalNIZI = totalNIZI - nIZI;
        }
    }

    /// @notice Update the global status.
    function _updateGlobalStatus() internal {
        if (block.number <= lastTouchBlock) {
            return;
        }
        if (lastTouchBlock >= endBlock) {
            return;
        }
        uint256 currBlockNumber = Math.min(block.number, endBlock);
        if (totalVLiquidity == 0) {
            lastTouchBlock = currBlockNumber;
            return;
        }

        for (uint256 i = 0; i < rewardInfosLen; i++) {
            // tokenReward < 2^25 * 2^64 * 2*10, 15 years, 1000 r/block
            uint256 tokenReward = (currBlockNumber - lastTouchBlock) * rewardInfos[i].rewardPerBlock;
            // tokenReward * Q128 < 2^(25 + 64 + 10 + 128)
            rewardInfos[i].accRewardPerShare = rewardInfos[i].accRewardPerShare + ((tokenReward * FixedPoints.Q128) / totalVLiquidity);
        }
        lastTouchBlock = currBlockNumber;
    }

    /// @notice compute validVLiquidity
    /// @param vLiquidity origin vLiquidity
    /// @param nIZI amount of boosted iZi
    function _computeValidVLiquidity(uint256 vLiquidity, uint256 nIZI)
        internal virtual
        view
        returns (uint256);

    /// @notice update a token status when touched
    /// @param tokenId id of TokenStatus obj in sub-contracts (same with uniswap nft id)
    /// @param validVLiquidity validVLiquidity, can be acquired by _computeValidVLiquidity(...)
    /// @param nIZI latest amount of iZi boost
    function _updateTokenStatus(
        uint256 tokenId,
        uint256 validVLiquidity,
        uint256 nIZI
    ) internal virtual;


    struct BaseTokenStatus {
        uint256 vLiquidity;
        uint256 validVLiquidity;
        uint256 nIZI;
        uint256[] lastTouchAccRewardPerShare;
    }

    /// @notice get base infomation from token status in sub-contracts
    /// @param tokenId id of TokenStatus obj in sub-contracts
    /// @return t contains base infomation (uint256 vLiquidity, uint256 validVLiquidity, uint256 nIZI, uint256[] lastTouchAccRewardPerShare)
    function getBaseTokenStatus(uint256 tokenId) internal virtual view returns(BaseTokenStatus memory t);

    /// @notice deposit iZi to an nft token
    /// @param tokenId nft already deposited
    /// @param deltaNIZI amount of izi to deposit
    function depositIZI(uint256 tokenId, uint256 deltaNIZI)
        external
        nonReentrant
    {
        require(owners[tokenId] == msg.sender, "NOT OWNER or NOT EXIST");
        require(address(iziToken) != address(0), "NOT BOOST");
        require(deltaNIZI > 0, "DEPOSIT IZI MUST BE POSITIVE");
        _collectReward(tokenId);
        BaseTokenStatus memory t = getBaseTokenStatus(tokenId);
        _updateNIZI(deltaNIZI, true);
        uint256 nIZI = t.nIZI + deltaNIZI;
        // update validVLiquidity
        uint256 validVLiquidity = _computeValidVLiquidity(t.vLiquidity, nIZI);
        _updateTokenStatus(tokenId, validVLiquidity, nIZI);

        // transfer iZi from user
        iziToken.safeTransferFrom(msg.sender, address(this), deltaNIZI);
    }

    /// @notice Collect pending reward for a single position. can be called by sub-contracts
    /// @param tokenId The related position id.
    function _collectReward(uint256 tokenId) internal {
        BaseTokenStatus memory t = getBaseTokenStatus(tokenId);

        _updateGlobalStatus();
        for (uint256 i = 0; i < rewardInfosLen; i++) {
            // multiplied by Q128 before
            uint256 _reward = (t.validVLiquidity * (rewardInfos[i].accRewardPerShare - t.lastTouchAccRewardPerShare[i])) / FixedPoints.Q128;
            if (_reward > 0) {
                IERC20(rewardInfos[i].rewardToken).safeTransferFrom(
                    rewardInfos[i].provider,
                    msg.sender,
                    _reward
                );
            }
            emit CollectReward(
                msg.sender,
                tokenId,
                rewardInfos[i].rewardToken,
                _reward
            );
        }

        // update validVLiquidity
        uint256 validVLiquidity = _computeValidVLiquidity(t.vLiquidity, t.nIZI);
        _updateTokenStatus(tokenId, validVLiquidity, t.nIZI);
    }

    /// @notice View function to get position ids staked here for an user.
    /// @param _user The related address.
    /// @return list of tokenId
    function getTokenIds(address _user)
        external
        view
        returns (uint256[] memory)
    {
        EnumerableSet.UintSet storage ids = tokenIds[_user];
        // push could not be used in memory array
        // we set the tokenIdList into a fixed-length array rather than dynamic
        uint256[] memory tokenIdList = new uint256[](ids.length());
        for (uint256 i = 0; i < ids.length(); i++) {
            tokenIdList[i] = ids.at(i);
        }
        return tokenIdList;
    }
    
    /// @notice Return reward multiplier over the given _from to _to block.
    /// @param _from The start block.
    /// @param _to The end block.
    function _getRewardBlockNum(uint256 _from, uint256 _to)
        internal
        view
        returns (uint256)
    {
        if (_from > _to) {
            return 0;
        }
        if (_to <= endBlock) {
            return _to - _from;
        } else if (_from >= endBlock) {
            return 0;
        } else {
            return endBlock - _from;
        }
    }

    /// @notice View function to see pending Reward for a single position.
    /// @param tokenId The related position id.
    /// @return list of pending reward amount for each reward ERC20-token of tokenId
    function pendingReward(uint256 tokenId)
        public
        view
        returns (uint256[] memory)
    {
        BaseTokenStatus memory t = getBaseTokenStatus(tokenId);
        uint256[] memory _reward = new uint256[](rewardInfosLen);
        for (uint256 i = 0; i < rewardInfosLen; i++) {
            uint256 tokenReward = _getRewardBlockNum(
                lastTouchBlock,
                block.number
            ) * rewardInfos[i].rewardPerBlock;
            uint256 rewardPerShare = rewardInfos[i].accRewardPerShare + (tokenReward * FixedPoints.Q128) / totalVLiquidity;
            // l * (currentAcc - lastAcc)
            _reward[i] = (t.validVLiquidity * (rewardPerShare - t.lastTouchAccRewardPerShare[i])) / FixedPoints.Q128;
        }
        return _reward;
    }

    /// @notice View function to see pending Rewards for an address.
    /// @param _user The related address.
    /// @return list of pending reward amount for each reward ERC20-token of this user
    function pendingRewards(address _user)
        external
        view
        returns (uint256[] memory)
    {
        uint256[] memory _reward = new uint256[](rewardInfosLen);
        for (uint256 j = 0; j < rewardInfosLen; j++) {
            _reward[j] = 0;
        }

        for (uint256 i = 0; i < tokenIds[_user].length(); i++) {
            uint256[] memory r = pendingReward(tokenIds[_user].at(i));
            for (uint256 j = 0; j < rewardInfosLen; j++) {
                _reward[j] += r[j];
            }
        }
        return _reward;
    }

    // Control fuctions for the contract owner and operators.

    /// @notice If something goes wrong, we can send back user's nft and locked assets
    /// @param tokenId The related position id.
    function emergenceWithdraw(uint256 tokenId) external virtual;

    /// @notice Set new reward end block.
    /// @param _endBlock New end block.
    function modifyEndBlock(uint256 _endBlock) external onlyOwner {
        require(_endBlock > block.number, "OUT OF DATE");
        _updateGlobalStatus();
        // jump if origin endBlock < block.number
        lastTouchBlock = block.number;
        endBlock = _endBlock;
        emit ModifyEndBlock(endBlock);
    }

    /// @notice Set new reward per block.
    /// @param rewardIdx which rewardInfo to modify
    /// @param _rewardPerBlock new reward per block
    function modifyRewardPerBlock(uint256 rewardIdx, uint256 _rewardPerBlock)
        external
        onlyOwner
    {
        require(rewardIdx < rewardInfosLen, "OUT OF REWARD INFO RANGE");
        _updateGlobalStatus();
        rewardInfos[rewardIdx].rewardPerBlock = _rewardPerBlock;
        emit ModifyRewardPerBlock(
            rewardInfos[rewardIdx].rewardToken,
            _rewardPerBlock
        );
    }


    /// @notice Set new reward provider.
    /// @param rewardIdx which rewardInfo to modify
    /// @param provider New provider
    function modifyProvider(uint256 rewardIdx, address provider)
        external
        onlyOwner
    {
        require(rewardIdx < rewardInfosLen, "OUT OF REWARD INFO RANGE");
        rewardInfos[rewardIdx].provider = provider;
        emit ModifyProvider(rewardInfos[rewardIdx].rewardToken, provider);
    }
}
function modifyRewardPerBlock(uint256 rewardIdx, uint256 _rewardPerBlock)
        external
        onlyOwner
    {
        require(rewardIdx < rewardInfosLen, "OUT OF REWARD INFO RANGE");
        _updateGlobalStatus();
        rewardInfos[rewardIdx].rewardPerBlock = _rewardPerBlock;
        emit ModifyRewardPerBlock(
            rewardInfos[rewardIdx].rewardToken,
            _rewardPerBlock
        );
    }
/// @notice Set new reward per block.
/// @param rewardIdx which rewardInfo to modify
/// @param _rewardPerBlock new reward per block