harb/src/LiquidityManager.sol

// SPDX-License-Identifier: GPL-3.0-or-later
pragma solidity ^0.8.20;

import {BloodX} from "src/BloodX.sol";
import "@uniswap/v3-core/contracts/libraries/TickMath.sol";
import "@uniswap/v3-periphery/contracts/libraries/LiquidityAmounts.sol";
import "@uniswap/v3-core/contracts/interfaces/IUniswapV3Pool.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

/**
 * @title LiquidityManager - A contract that supports the $bloodX ecosystem. It 
 *          protects the communities liquidity while allowing a manager role to 
 *          take strategic liqudity positions.
 */
contract LiquidityManager {

    // default fee of 1%
    uint24 constant FEE = uint24(10_000);

    /// @notice WETH9, which is an underlying pool token.
    address immutable WETH;

    struct AddLiquidityParams {
        address token0;
        address token1;
        int24 tickLower;
        int24 tickUpper;
        uint256 amount0Desired;
        uint256 amount1Desired;
        uint256 amount0Min;
        uint256 amount1Min;
        uint256 deadline;
    }

    struct DecreaseLiquidityParams {
        address token0;
        address token1;
        int24 tickLower;
        int24 tickUpper;
        uint128 liquidity;
        uint256 amount0Min;
        uint256 amount1Min;
        uint256 deadline;
    }

    struct TokenPosition {
        // the liquidity of the position
        uint128 liquidity;
        // the fee growth of the aggregate position as of the last action on the individual position
        uint256 feeGrowthInside0LastX128;
        uint256 feeGrowthInside1LastX128;
        // how many uncollected tokens are owed to the position, as of the last computation
        uint128 tokensOwed0;
        uint128 tokensOwed1;
    }

    /// @dev The token ID position data
    mapping(bytes32 => TokenPosition) private _positions;

    constructor(address _weth) {
        WETH = _weth;
    }

    function getToken(address token0, address token1) internal view returns (address) {
        bool token0isWeth = (token0 == WETH);
        require(token0isWeth || token1 == WETH, "token error");
        return (token0isWeth) ? token1 : token0;
    }

    function posKey(address _token, uint24 _tickLower, uint24, tickUpper) internal pure returns (uint256) {
        return uint160(_token) << 48 + tickLower << 24 + tickUpper;
    }

    function positions(address _token, int24 _tickLower, int24 _tickUpper) external view
        returns (
            uint128 liquidity,
            uint256 feeGrowthInside0LastX128,
            uint256 feeGrowthInside1LastX128,
            uint128 tokensOwed0,
            uint128 tokensOwed1
        )
    {
        TokenPosition memory position = _positions[posKey(_token, tickLower, tickUpper)];
        return (
            position.liquidity,
            position.feeGrowthInside0LastX128,
            position.feeGrowthInside1LastX128,
            position.tokensOwed0,
            position.tokensOwed1
        );
    }

    /// @inheritdoc IUniswapV3MintCallback
    function uniswapV3MintCallback(
        uint256 amount0Owed,
        uint256 amount1Owed,
        bytes calldata data
    ) external override {
        PoolAddress.PoolKey memory poolKey = abi.decode(data, (PoolAddress.PoolKey));
        CallbackValidation.verifyCallback(factory, poolKey);

        if (amount0Owed > 0) ERC20(poolKey.token0).transfer(msg.sender, amount0Owed);
        if (amount1Owed > 0) ERC20(poolKey.token1).transfer(msg.sender, amount1Owed);
    }

    /// @notice Add liquidity to an initialized pool
    function addLiquidity(AddLiquidityParams memory params)
        external
        checkDeadline(params.deadline)
        returns (
            uint128 liquidity,
            uint256 amount0,
            uint256 amount1
        )
    {
        PoolAddress.PoolKey memory poolKey =
            PoolAddress.PoolKey({token0: params.token0, token1: params.token1, fee: FEE});
        pool = IUniswapV3Pool(PoolAddress.computeAddress(factory, poolKey));

        // compute the liquidity amount
        {
            (uint160 sqrtPriceX96, , , , , , ) = pool.slot0();
            uint160 sqrtRatioAX96 = TickMath.getSqrtRatioAtTick(params.tickLower);
            uint160 sqrtRatioBX96 = TickMath.getSqrtRatioAtTick(params.tickUpper);

            liquidity = LiquidityAmounts.getLiquidityForAmounts(
                sqrtPriceX96,
                sqrtRatioAX96,
                sqrtRatioBX96,
                params.amount0Desired,
                params.amount1Desired
            );
        }

        (amount0, amount1) = pool.mint(
            address(this),
            params.tickLower,
            params.tickUpper,
            liquidity,
            abi.encode(PoolAddress.PoolKey(poolKey))
        );

        require(amount0 >= params.amount0Min && amount1 >= params.amount1Min, 'Price slippage check');

        bytes32 positionKey = PositionKey.compute(address(this), params.tickLower, params.tickUpper);

        // this is now updated to the current transaction
        (, uint256 feeGrowthInside0LastX128, uint256 feeGrowthInside1LastX128, , ) = pool.positions(positionKey);


        TokenPosition memory position = _positions[posKey(getToken(params.token0, params.token1), tickLower, tickUpper)];
        if (liquidity == 0) {
            // create entry
            position =  TokenPosition({
                liquidity: liquidity,
                feeGrowthInside0LastX128: feeGrowthInside0LastX128,
                feeGrowthInside1LastX128: feeGrowthInside1LastX128,
                tokensOwed0: 0,
                tokensOwed1: 0
            });
        } else {
            // update entry
            position.tokensOwed0 += uint128(
                FullMath.mulDiv(
                    feeGrowthInside0LastX128 - position.feeGrowthInside0LastX128,
                    position.liquidity,
                    FixedPoint128.Q128
                )
            );
            position.tokensOwed1 += uint128(
                FullMath.mulDiv(
                    feeGrowthInside1LastX128 - position.feeGrowthInside1LastX128,
                    position.liquidity,
                    FixedPoint128.Q128
                )
            );

            position.feeGrowthInside0LastX128 = feeGrowthInside0LastX128;
            position.feeGrowthInside1LastX128 = feeGrowthInside1LastX128;
            position.liquidity += liquidity;
        }

        emit IncreaseLiquidity(tokenId, liquidity, amount0, amount1);
    }

    /// @inheritdoc INonfungiblePositionManager
    function decreaseLiquidity(DecreaseLiquidityParams calldata params)
        external
        payable
        override
        checkDeadline(params.deadline)
        returns (uint256 amount0, uint256 amount1)
    {
        require(params.liquidity > 0);

        TokenPosition memory position = _positions[posKey(getToken(params.token0, params.token1), tickLower, tickUpper)];
        uint128 positionLiquidity = position.liquidity;
        require(positionLiquidity >= params.liquidity);

        PoolAddress.PoolKey memory poolKey =
            PoolAddress.PoolKey({token0: params.token0, token1: params.token1, fee: FEE});
        pool = IUniswapV3Pool(PoolAddress.computeAddress(factory, poolKey));

        (amount0, amount1) = pool.burn(params.tickLower, params.tickUpper, params.liquidity);

        require(amount0 >= params.amount0Min && amount1 >= params.amount1Min, 'Price slippage check');

        bytes32 positionKey = PositionKey.compute(address(this), params.tickLower, params.tickUpper);
        // this is now updated to the current transaction
        (, uint256 feeGrowthInside0LastX128, uint256 feeGrowthInside1LastX128, , ) = pool.positions(positionKey);

        position.tokensOwed0 +=
            uint128(amount0) +
            uint128(
                FullMath.mulDiv(
                    feeGrowthInside0LastX128 - position.feeGrowthInside0LastX128,
                    positionLiquidity,
                    FixedPoint128.Q128
                )
            );
        position.tokensOwed1 +=
            uint128(amount1) +
            uint128(
                FullMath.mulDiv(
                    feeGrowthInside1LastX128 - position.feeGrowthInside1LastX128,
                    positionLiquidity,
                    FixedPoint128.Q128
                )
            );

        position.feeGrowthInside0LastX128 = feeGrowthInside0LastX128;
        position.feeGrowthInside1LastX128 = feeGrowthInside1LastX128;
        // subtraction is safe because we checked positionLiquidity is gte params.liquidity
        position.liquidity = positionLiquidity - params.liquidity;

        emit DecreaseLiquidity(params.tokenId, params.liquidity, amount0, amount1);
    }
}