// SPDX-License-Identifier: ISC
pragma solidity ^0.8.20;

/// Smoke-test contract: a counter with an event, a view, a revert path and a registry call from its constructor.
interface IDeveloperRegistry { function register(address account, address payee) external; }

contract Counter {
    uint256 public count;
    event Incremented(address indexed by, uint256 newCount);

    constructor(address registry, address payee) {
        if (registry != address(0)) {
            IDeveloperRegistry(registry).register(address(this), payee);
        }
    }

    function increment(uint256 by) external returns (uint256) {
        require(by > 0, "Counter: zero");
        count += by;
        emit Incremented(msg.sender, count);
        return count;
    }

    function hashLoop(uint256 rounds) external pure returns (bytes32 h) {
        for (uint256 i = 0; i < rounds; i++) {
            h = keccak256(abi.encodePacked(h, i));
        }
    }
}