Counter.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import {BaseHook} from "v4-periphery/BaseHook.sol";

import {Hooks} from "@uniswap/v4-core/contracts/libraries/Hooks.sol";
import {IPoolManager} from "@uniswap/v4-core/contracts/interfaces/IPoolManager.sol";
import {PoolKey} from "@uniswap/v4-core/contracts/types/PoolKey.sol";
import {PoolId, PoolIdLibrary} from "@uniswap/v4-core/contracts/types/PoolId.sol";
import {BalanceDelta} from "@uniswap/v4-core/contracts/types/BalanceDelta.sol";
import {MockERC20} from "solmate/test/utils/mocks/MockERC20.sol";

contract Counter is BaseHook {
    using PoolIdLibrary for PoolKey;

    // NOTE: ---------------------------------------------------------
    // state variables should typically be unique to a pool
    // a single hook contract should be able to service multiple pools
    // ---------------------------------------------------------------

    mapping(PoolId => uint256 count) public beforeSwapCount;
    mapping(PoolId => uint256 count) public afterSwapCount;

    mapping(PoolId => uint256 count) public beforeModifyPositionCount;
    mapping(PoolId => uint256 count) public afterModifyPositionCount;

    constructor(IPoolManager _poolManager) BaseHook(_poolManager) {}

    function getHooksCalls() public pure override returns (Hooks.Calls memory) {
        return Hooks.Calls({
            beforeInitialize: false,
            afterInitialize: false,
            beforeModifyPosition: true,
            afterModifyPosition: true,
            beforeSwap: true,
            afterSwap: true,
            beforeDonate: false,
            afterDonate: false
        });
    }

    // -----------------------------------------------
    // NOTE: see IHooks.sol for function documentation
    // -----------------------------------------------

    function beforeSwap(address, PoolKey calldata key, IPoolManager.SwapParams calldata, bytes calldata)
        external
        override
        returns (bytes4)
    {
        beforeSwapCount[key.toId()]++;
        return BaseHook.beforeSwap.selector;
    }

    function afterSwap(address, PoolKey calldata key, IPoolManager.SwapParams calldata, BalanceDelta, bytes calldata)
        external
        override
        returns (bytes4)
    {
        afterSwapCount[key.toId()]++;
        return BaseHook.afterSwap.selector;
    }

    function beforeModifyPosition(
        address,
        PoolKey calldata key,
        IPoolManager.ModifyPositionParams calldata,
        bytes calldata
    ) external override returns (bytes4) {
        beforeModifyPositionCount[key.toId()]++;
        return BaseHook.beforeModifyPosition.selector;
    }

    function afterModifyPosition(
        address,
        PoolKey calldata key,
        IPoolManager.ModifyPositionParams calldata,
        BalanceDelta,
        bytes calldata
    ) external override returns (bytes4) {
        afterModifyPositionCount[key.toId()]++;
        return BaseHook.afterModifyPosition.selector;
    }
}