// SPDX-License-Identifier: GPL-3.0-or-later
pragma solidity 0.7.6;

library Tick {
    struct GrowthInfo {
        uint256 feeX128;
        int256 twPremiumX96;
        int256 twPremiumDivBySqrtPriceX96;
    }

    struct FundingGrowthRangeInfo {
        int256 twPremiumGrowthInsideX96;
        int256 twPremiumGrowthBelowX96;
        int256 twPremiumDivBySqrtPriceGrowthInsideX96;
    }

    /// @dev call this function only if (liquidityGrossBefore == 0 && liquidityDelta != 0)
    /// @dev per Uniswap: we assume that all growths before a tick is initialized happen "below" the tick
    function initialize(
        mapping(int24 => GrowthInfo) storage self,
        int24 tick,
        int24 currentTick,
        GrowthInfo memory globalGrowthInfo
    ) internal {
        if (tick <= currentTick) {
            GrowthInfo storage growthInfo = self[tick];
            growthInfo.feeX128 = globalGrowthInfo.feeX128;
            growthInfo.twPremiumX96 = globalGrowthInfo.twPremiumX96;
            growthInfo.twPremiumDivBySqrtPriceX96 = globalGrowthInfo.twPremiumDivBySqrtPriceX96;
        }
    }

    function cross(
        mapping(int24 => GrowthInfo) storage self,
        int24 tick,
        GrowthInfo memory globalGrowthInfo
    ) internal {
        GrowthInfo storage growthInfo = self[tick];
        growthInfo.feeX128 = globalGrowthInfo.feeX128 - growthInfo.feeX128;
        growthInfo.twPremiumX96 = globalGrowthInfo.twPremiumX96 - growthInfo.twPremiumX96;
        growthInfo.twPremiumDivBySqrtPriceX96 =
            globalGrowthInfo.twPremiumDivBySqrtPriceX96 -
            growthInfo.twPremiumDivBySqrtPriceX96;
    }

    function clear(mapping(int24 => GrowthInfo) storage self, int24 tick) internal {
        delete self[tick];
    }

    /// @dev all values in this function are scaled by 2^128 (X128), thus adding the suffix to external params
    /// @return feeGrowthInsideX128 this value can underflow per Tick.feeGrowthOutside specs
    function getFeeGrowthInsideX128(
        mapping(int24 => GrowthInfo) storage self,
        int24 lowerTick,
        int24 upperTick,
        int24 currentTick,
        uint256 feeGrowthGlobalX128
    ) internal view returns (uint256 feeGrowthInsideX128) {
        uint256 lowerFeeGrowthOutside = self[lowerTick].feeX128;
        uint256 upperFeeGrowthOutside = self[upperTick].feeX128;

        uint256 feeGrowthBelow =
            currentTick >= lowerTick ? lowerFeeGrowthOutside : feeGrowthGlobalX128 - lowerFeeGrowthOutside;
        uint256 feeGrowthAbove =
            currentTick < upperTick ? upperFeeGrowthOutside : feeGrowthGlobalX128 - upperFeeGrowthOutside;

        return feeGrowthGlobalX128 - feeGrowthBelow - feeGrowthAbove;
    }

    /// @return all values returned can underflow per feeGrowthOutside specs;
    ///         see https://www.notion.so/32990980ba8b43859f6d2541722a739b
    function getAllFundingGrowth(
        mapping(int24 => GrowthInfo) storage self,
        int24 lowerTick,
        int24 upperTick,
        int24 currentTick,
        int256 twPremiumGrowthGlobalX96,
        int256 twPremiumDivBySqrtPriceGrowthGlobalX96
    ) internal view returns (FundingGrowthRangeInfo memory) {
        GrowthInfo storage lowerTickGrowthInfo = self[lowerTick];
        GrowthInfo storage upperTickGrowthInfo = self[upperTick];

        int256 lowerTwPremiumGrowthOutsideX96 = lowerTickGrowthInfo.twPremiumX96;
        int256 upperTwPremiumGrowthOutsideX96 = upperTickGrowthInfo.twPremiumX96;

        FundingGrowthRangeInfo memory fundingGrowthRangeInfo;
        fundingGrowthRangeInfo.twPremiumGrowthBelowX96 = currentTick >= lowerTick
            ? lowerTwPremiumGrowthOutsideX96
            : twPremiumGrowthGlobalX96 - lowerTwPremiumGrowthOutsideX96;
        int256 twPremiumGrowthAboveX96 =
            currentTick < upperTick
                ? upperTwPremiumGrowthOutsideX96
                : twPremiumGrowthGlobalX96 - upperTwPremiumGrowthOutsideX96;

        int256 lowerTwPremiumDivBySqrtPriceGrowthOutsideX96 = lowerTickGrowthInfo.twPremiumDivBySqrtPriceX96;
        int256 upperTwPremiumDivBySqrtPriceGrowthOutsideX96 = upperTickGrowthInfo.twPremiumDivBySqrtPriceX96;

        int256 twPremiumDivBySqrtPriceGrowthBelowX96 =
            currentTick >= lowerTick
                ? lowerTwPremiumDivBySqrtPriceGrowthOutsideX96
                : twPremiumDivBySqrtPriceGrowthGlobalX96 - lowerTwPremiumDivBySqrtPriceGrowthOutsideX96;
        int256 twPremiumDivBySqrtPriceGrowthAboveX96 =
            currentTick < upperTick
                ? upperTwPremiumDivBySqrtPriceGrowthOutsideX96
                : twPremiumDivBySqrtPriceGrowthGlobalX96 - upperTwPremiumDivBySqrtPriceGrowthOutsideX96;

        fundingGrowthRangeInfo.twPremiumGrowthInsideX96 =
            twPremiumGrowthGlobalX96 -
            fundingGrowthRangeInfo.twPremiumGrowthBelowX96 -
            twPremiumGrowthAboveX96;
        fundingGrowthRangeInfo.twPremiumDivBySqrtPriceGrowthInsideX96 =
            twPremiumDivBySqrtPriceGrowthGlobalX96 -
            twPremiumDivBySqrtPriceGrowthBelowX96 -
            twPremiumDivBySqrtPriceGrowthAboveX96;

        return fundingGrowthRangeInfo;
    }
}