Danro-Jump/Assets/Scripts/Runtime/UI/MainMenu/MainMenuController.cs

using UnityEngine;
using UnityEngine.SceneManagement;
using UnityEngine.UIElements;

namespace DanroJump.UI.MainMenu
{
    [RequireComponent(typeof(UIDocument))]
    public sealed class MainMenuController : MonoBehaviour
    {
        [SerializeField] private string gameplaySceneName = "Game";
        [SerializeField] private string settingsSceneName = "";

        private UIDocument document;
        private Button startButton;
        private Button settingsButton;
        private Button serviceButton;
        private Button quitButton;
        private Label versionLabel;

        private void Awake()
        {
            document = GetComponent<UIDocument>();
        }

        private void OnEnable()
        {
            var root = document.rootVisualElement;

            startButton = root.Q<Button>("StartButton");
            settingsButton = root.Q<Button>("SettingsButton");
            serviceButton = root.Q<Button>("ServiceButton");
            quitButton = root.Q<Button>("QuitButton");
            versionLabel = root.Q<Label>("VersionLabel");

            RegisterCallbacks();
            RefreshStaticLabels();
        }

        private void OnDisable()
        {
            UnregisterCallbacks();
        }

        private void RegisterCallbacks()
        {
            if (startButton != null)
            {
                startButton.clicked += StartGame;
            }

            if (settingsButton != null)
            {
                settingsButton.clicked += OpenSettings;
            }

            if (serviceButton != null)
            {
                serviceButton.clicked += OpenServicePanel;
            }

            if (quitButton != null)
            {
                quitButton.clicked += QuitApplication;
            }
        }

        private void UnregisterCallbacks()
        {
            if (startButton != null)
            {
                startButton.clicked -= StartGame;
            }

            if (settingsButton != null)
            {
                settingsButton.clicked -= OpenSettings;
            }

            if (serviceButton != null)
            {
                serviceButton.clicked -= OpenServicePanel;
            }

            if (quitButton != null)
            {
                quitButton.clicked -= QuitApplication;
            }
        }

        private void RefreshStaticLabels()
        {
            if (versionLabel != null)
            {
                versionLabel.text = $"Версия: {Application.version}";
            }
        }

        private void StartGame()
        {
            if (!SceneExists(gameplaySceneName))
            {
                Debug.LogWarning($"Gameplay scene '{gameplaySceneName}' is not available in Build Settings yet.");
                return;
            }

            SceneManager.LoadSceneAsync(gameplaySceneName, LoadSceneMode.Single);
        }

        private void OpenSettings()
        {
            if (!string.IsNullOrWhiteSpace(settingsSceneName) && SceneExists(settingsSceneName))
            {
                SceneManager.LoadSceneAsync(settingsSceneName, LoadSceneMode.Single);
                return;
            }

            Debug.Log("Main menu settings entry selected. Service settings UI will be connected later.");
        }

        private void OpenServicePanel()
        {
            Debug.Log("Service panel entry selected. Operator tools will be connected later.");
        }

        private void QuitApplication()
        {
#if UNITY_EDITOR
            UnityEditor.EditorApplication.isPlaying = false;
#else
            Application.Quit();
#endif
        }

        private static bool SceneExists(string sceneName)
        {
            if (string.IsNullOrWhiteSpace(sceneName))
            {
                return false;
            }

            for (var index = 0; index < SceneManager.sceneCountInBuildSettings; index++)
            {
                var scenePath = SceneUtility.GetScenePathByBuildIndex(index);
                var candidateName = System.IO.Path.GetFileNameWithoutExtension(scenePath);

                if (candidateName == sceneName)
                {
                    return true;
                }
            }

            return false;
        }
    }
}