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

namespace MegaKoop.UI
{
    /// <summary>
    /// Controller pro Main Menu s UI Toolkit
    /// </summary>
    public class MainMenuController : MonoBehaviour
    {
        [Header("UI Document")]
        [SerializeField] private UIDocument uiDocument;
        
        [Header("Scene Names")]
        [SerializeField] private string gameSceneName = "GameScene";
        
        [Header("Audio")]
        [SerializeField] private AudioSource audioSource;
        [SerializeField] private AudioClip buttonClickSound;
        [SerializeField] private AudioClip buttonHoverSound;
        
        // Root element
        private VisualElement root;
        
        // Main Menu Elements
        private Button newGameButton;
        private Button continueButton;
        private Button multiplayerButton;
        private Button settingsButton;
        private Button creditsButton;
        private Button quitButton;
        
        // Settings Panel Elements
        private VisualElement settingsPanel;
        private DropdownField qualityDropdown;
        private Toggle fullscreenToggle;
        private DropdownField resolutionDropdown;
        private Slider masterVolumeSlider;
        private Slider musicVolumeSlider;
        private Slider sfxVolumeSlider;
        private Button applyButton;
        private Button backButton;
        
        private void OnEnable()
        {
            // Získání UI Document
            if (uiDocument == null)
                uiDocument = GetComponent<UIDocument>();
            
            root = uiDocument.rootVisualElement;
            
            // Inicializace UI elementů
            InitializeMenuButtons();
            InitializeSettingsPanel();
            
            // Registrace event handlerů
            RegisterButtonEvents();
            
            // Načtení nastavení
            LoadSettings();
        }
        
        private void OnDisable()
        {
            // Odregistrování event handlerů
            UnregisterButtonEvents();
        }
        
        #region Initialization
        
        private void InitializeMenuButtons()
        {
            newGameButton = root.Q<Button>("NewGameButton");
            continueButton = root.Q<Button>("ContinueButton");
            multiplayerButton = root.Q<Button>("MultiplayerButton");
            settingsButton = root.Q<Button>("SettingsButton");
            creditsButton = root.Q<Button>("CreditsButton");
            quitButton = root.Q<Button>("QuitButton");
            
            // Kontrola, zda existuje uložená hra
            continueButton.SetEnabled(HasSaveGame());
        }
        
        private void InitializeSettingsPanel()
        {
            settingsPanel = root.Q<VisualElement>("SettingsPanel");
            
            // Graphics Settings
            qualityDropdown = root.Q<DropdownField>("QualityDropdown");
            fullscreenToggle = root.Q<Toggle>("FullscreenToggle");
            resolutionDropdown = root.Q<DropdownField>("ResolutionDropdown");
            
            // Audio Settings
            masterVolumeSlider = root.Q<Slider>("MasterVolumeSlider");
            musicVolumeSlider = root.Q<Slider>("MusicVolumeSlider");
            sfxVolumeSlider = root.Q<Slider>("SFXVolumeSlider");
            
            // Buttons
            applyButton = root.Q<Button>("ApplyButton");
            backButton = root.Q<Button>("BackButton");
            
            // Setup dropdowns
            SetupQualityDropdown();
            SetupResolutionDropdown();
        }
        
        private void SetupQualityDropdown()
        {
            if (qualityDropdown == null) return;
            
            var qualityNames = QualitySettings.names;
            qualityDropdown.choices = new System.Collections.Generic.List<string>(qualityNames);
            qualityDropdown.value = qualityNames[QualitySettings.GetQualityLevel()];
        }
        
        private void SetupResolutionDropdown()
        {
            if (resolutionDropdown == null) return;
            
            var resolutions = new System.Collections.Generic.List<string>();
            foreach (var resolution in Screen.resolutions)
            {
                resolutions.Add($"{resolution.width} x {resolution.height} @ {resolution.refreshRate}Hz");
            }
            
            resolutionDropdown.choices = resolutions;
            resolutionDropdown.value = $"{Screen.currentResolution.width} x {Screen.currentResolution.height} @ {Screen.currentResolution.refreshRate}Hz";
        }
        
        #endregion
        
        #region Event Registration
        
        private void RegisterButtonEvents()
        {
            // Main Menu Buttons
            if (newGameButton != null)
            {
                newGameButton.clicked += OnNewGameClicked;
                AddHoverEffects(newGameButton);
            }
            
            if (continueButton != null)
            {
                continueButton.clicked += OnContinueClicked;
                AddHoverEffects(continueButton);
            }
            
            if (multiplayerButton != null)
            {
                multiplayerButton.clicked += OnMultiplayerClicked;
                AddHoverEffects(multiplayerButton);
            }
            
            if (settingsButton != null)
            {
                settingsButton.clicked += OnSettingsClicked;
                AddHoverEffects(settingsButton);
            }
            
            if (creditsButton != null)
            {
                creditsButton.clicked += OnCreditsClicked;
                AddHoverEffects(creditsButton);
            }
            
            if (quitButton != null)
            {
                quitButton.clicked += OnQuitClicked;
                AddHoverEffects(quitButton);
            }
            
            // Settings Panel Buttons
            if (applyButton != null)
            {
                applyButton.clicked += OnApplySettingsClicked;
                AddHoverEffects(applyButton);
            }
            
            if (backButton != null)
            {
                backButton.clicked += OnBackFromSettingsClicked;
                AddHoverEffects(backButton);
            }
        }
        
        private void UnregisterButtonEvents()
        {
            if (newGameButton != null) newGameButton.clicked -= OnNewGameClicked;
            if (continueButton != null) continueButton.clicked -= OnContinueClicked;
            if (multiplayerButton != null) multiplayerButton.clicked -= OnMultiplayerClicked;
            if (settingsButton != null) settingsButton.clicked -= OnSettingsClicked;
            if (creditsButton != null) creditsButton.clicked -= OnCreditsClicked;
            if (quitButton != null) quitButton.clicked -= OnQuitClicked;
            if (applyButton != null) applyButton.clicked -= OnApplySettingsClicked;
            if (backButton != null) backButton.clicked -= OnBackFromSettingsClicked;
        }
        
        private void AddHoverEffects(Button button)
        {
            button.RegisterCallback<MouseEnterEvent>(evt => OnButtonHover());
        }
        
        #endregion
        
        #region Button Callbacks
        
        private void OnNewGameClicked()
        {
            PlayButtonClickSound();
            Debug.Log("Starting New Game...");
            
            // Vymazání uložené hry
            PlayerPrefs.DeleteKey("SaveGame");
            
            // Načtení herní scény
            LoadGameScene();
        }
        
        private void OnContinueClicked()
        {
            PlayButtonClickSound();
            Debug.Log("Continuing Game...");
            
            // Načtení uložené hry
            LoadSaveGame();
            
            // Načtení herní scény
            LoadGameScene();
        }
        
        private void OnMultiplayerClicked()
        {
            PlayButtonClickSound();
            Debug.Log("Opening Multiplayer Menu...");
            
            // TODO: Implementovat multiplayer menu
        }
        
        private void OnSettingsClicked()
        {
            PlayButtonClickSound();
            Debug.Log("Opening Settings...");
            ShowSettingsPanel();
        }
        
        private void OnCreditsClicked()
        {
            PlayButtonClickSound();
            Debug.Log("Showing Credits...");
            
            // TODO: Implementovat credits screen
        }
        
        private void OnQuitClicked()
        {
            PlayButtonClickSound();
            Debug.Log("Quitting Game...");
            
            #if UNITY_EDITOR
                UnityEditor.EditorApplication.isPlaying = false;
            #else
                Application.Quit();
            #endif
        }
        
        private void OnApplySettingsClicked()
        {
            PlayButtonClickSound();
            ApplySettings();
            SaveSettings();
            Debug.Log("Settings Applied!");
        }
        
        private void OnBackFromSettingsClicked()
        {
            PlayButtonClickSound();
            HideSettingsPanel();
        }
        
        private void OnButtonHover()
        {
            PlayButtonHoverSound();
        }
        
        #endregion
        
        #region Settings Management
        
        private void ShowSettingsPanel()
        {
            if (settingsPanel != null)
            {
                settingsPanel.RemoveFromClassList("hidden");
            }
        }
        
        private void HideSettingsPanel()
        {
            if (settingsPanel != null)
            {
                settingsPanel.AddToClassList("hidden");
            }
        }
        
        private void ApplySettings()
        {
            // Graphics Settings
            if (qualityDropdown != null)
            {
                int qualityIndex = qualityDropdown.index;
                QualitySettings.SetQualityLevel(qualityIndex);
            }
            
            if (fullscreenToggle != null)
            {
                Screen.fullScreen = fullscreenToggle.value;
            }
            
            if (resolutionDropdown != null && resolutionDropdown.index >= 0)
            {
                var resolution = Screen.resolutions[resolutionDropdown.index];
                Screen.SetResolution(resolution.width, resolution.height, Screen.fullScreen);
            }
            
            // Audio Settings
            if (masterVolumeSlider != null)
            {
                AudioListener.volume = masterVolumeSlider.value / 100f;
            }
            
            // TODO: Implementovat music a SFX volume přes audio mixer
        }
        
        private void SaveSettings()
        {
            PlayerPrefs.SetInt("QualityLevel", QualitySettings.GetQualityLevel());
            PlayerPrefs.SetInt("Fullscreen", Screen.fullScreen ? 1 : 0);
            PlayerPrefs.SetInt("ResolutionWidth", Screen.currentResolution.width);
            PlayerPrefs.SetInt("ResolutionHeight", Screen.currentResolution.height);
            
            if (masterVolumeSlider != null)
                PlayerPrefs.SetFloat("MasterVolume", masterVolumeSlider.value);
            if (musicVolumeSlider != null)
                PlayerPrefs.SetFloat("MusicVolume", musicVolumeSlider.value);
            if (sfxVolumeSlider != null)
                PlayerPrefs.SetFloat("SFXVolume", sfxVolumeSlider.value);
            
            PlayerPrefs.Save();
        }
        
        private void LoadSettings()
        {
            // Graphics Settings
            if (qualityDropdown != null)
            {
                int qualityLevel = PlayerPrefs.GetInt("QualityLevel", QualitySettings.GetQualityLevel());
                qualityDropdown.index = qualityLevel;
            }
            
            if (fullscreenToggle != null)
            {
                fullscreenToggle.value = PlayerPrefs.GetInt("Fullscreen", 1) == 1;
            }
            
            // Audio Settings
            if (masterVolumeSlider != null)
            {
                float masterVolume = PlayerPrefs.GetFloat("MasterVolume", 100f);
                masterVolumeSlider.value = masterVolume;
                AudioListener.volume = masterVolume / 100f;
            }
            
            if (musicVolumeSlider != null)
            {
                musicVolumeSlider.value = PlayerPrefs.GetFloat("MusicVolume", 80f);
            }
            
            if (sfxVolumeSlider != null)
            {
                sfxVolumeSlider.value = PlayerPrefs.GetFloat("SFXVolume", 100f);
            }
        }
        
        #endregion
        
        #region Game Management
        
        private bool HasSaveGame()
        {
            return PlayerPrefs.HasKey("SaveGame");
        }
        
        private void LoadSaveGame()
        {
            // TODO: Implementovat načítání save game
            string saveData = PlayerPrefs.GetString("SaveGame", "");
            Debug.Log($"Loading save game: {saveData}");
        }
        
        private void LoadGameScene()
        {
            // Načtení herní scény pomocí async loading
            StartCoroutine(LoadSceneAsync(gameSceneName));
        }
        
        private System.Collections.IEnumerator LoadSceneAsync(string sceneName)
        {
            AsyncOperation asyncLoad = SceneManager.LoadSceneAsync(sceneName);
            
            while (!asyncLoad.isDone)
            {
                // Zde můžete zobrazit loading bar
                float progress = Mathf.Clamp01(asyncLoad.progress / 0.9f);
                Debug.Log($"Loading progress: {progress * 100}%");
                yield return null;
            }
        }
        
        #endregion
        
        #region Audio
        
        private void PlayButtonClickSound()
        {
            if (audioSource != null && buttonClickSound != null)
            {
                audioSource.PlayOneShot(buttonClickSound);
            }
        }
        
        private void PlayButtonHoverSound()
        {
            if (audioSource != null && buttonHoverSound != null)
            {
                audioSource.PlayOneShot(buttonHoverSound, 0.5f);
            }
        }
        
        #endregion
    }
}