// SPDX-License-Identifier: MIT
pragma solidity ^0.8.26;

contract Counter {
    uint256 public number;
    address public owner;

    error NotOwner();

    event NumberChanged(uint256 previousNumber, uint256 newNumber);

    constructor(uint256 initialNumber) {
        owner = msg.sender;
        number = initialNumber;
    }

    function setNumber(uint256 newNumber) external {
        if (msg.sender != owner) {
            revert NotOwner();
        }

        uint256 previousNumber = number;
        number = newNumber;
        emit NumberChanged(previousNumber, newNumber);
    }

    function increment() external {
        uint256 previousNumber = number;
        number++;
        emit NumberChanged(previousNumber, number);
    }
}