using UnityEngine;
using UnityEngine.UI;
using System.Collections;
using System.Collections.Generic;

public class AudioManager : MonoBehaviour
{
    public static AudioManager Instance;

    [Header("Audio Sources")]
    public AudioSource musicSource;     // We'll assign MusicPlayer here
    public AudioSource sfxSource;       // For sound effects

    [Header("Music Library")]
    [Tooltip("Add your music files here")]
    public AudioClip[] musicLibrary;
    [Tooltip("Should music shuffle randomly?")]
    public bool shuffleMusic = true;
    [Tooltip("Should music loop the playlist?")]
    public bool loopPlaylist = true;
    [Tooltip("Time to fade between tracks (seconds)")]
    public float fadeDuration = 2f;

    [Header("UI Elements")]
    public Slider volumeSlider;         // We'll assign VolumeSlider here

    [Header("Volume Settings")]
    [Range(0f, 1f)]
    public float masterVolume = 1f;
    [Range(0f, 1f)]
    public float musicVolume = 1f;
    [Range(0f, 1f)]
    public float sfxVolume = 1f;

    [Header("Current Track Info")]
    [SerializeField] private int currentTrackIndex = 0;
    [SerializeField] private bool isPlaying = false;
    [SerializeField] private bool isFading = false;
    private List<int> shuffledIndices;
    private int shufflePosition = 0;    void Awake()
    {
        // Singleton pattern
        if (Instance != null && Instance != this)
        {
            Destroy(gameObject);
            return;
        }
        
        Instance = this;
        DontDestroyOnLoad(gameObject);
        
        // Subscribe to scene loaded events to refresh UI
        UnityEngine.SceneManagement.SceneManager.sceneLoaded += OnSceneLoaded;
    }

    void OnDestroy()
    {
        // Unsubscribe from scene events
        UnityEngine.SceneManagement.SceneManager.sceneLoaded -= OnSceneLoaded;
    }

    // Called when a new scene loads
    void OnSceneLoaded(UnityEngine.SceneManagement.Scene scene, UnityEngine.SceneManagement.LoadSceneMode mode)
    {
        Debug.Log($"AudioManager: Scene '{scene.name}' loaded. Current volume before setup: {musicVolume}");
        
        // Reset volumeSlider reference since it's a new scene
        volumeSlider = null;
        
        // Delay setup to ensure all UI elements are initialized
        StartCoroutine(DelayedUISetup());
    }

    IEnumerator DelayedUISetup()
    {
        // Wait a frame for UI to initialize
        yield return new WaitForEndOfFrame();
        
        // Re-load volume settings to ensure they're current
        LoadVolumeSettings();
        Debug.Log($"AudioManager: Volume reloaded from PlayerPrefs: {musicVolume}");
        
        // Setup UI sliders with current volume values
        SetupUISliders();
        
        // Ensure volume is applied correctly to audio source
        ApplyVolumeSettings();
        
        // If music is playing, ensure it has correct volume
        if (musicSource != null && musicSource.isPlaying)
        {
            musicSource.volume = musicVolume * masterVolume;
            Debug.Log($"AudioManager: Applied volume {musicVolume * masterVolume} to currently playing track");
        }
        
        Debug.Log($"AudioManager: Scene setup complete. Final volume: {musicVolume}");
    }

    void Start()
    {
        Debug.Log("AudioManager: Start() beginning...");
        
        // Quick validation of music library
        ValidateMusicLibrary();
        
        // Load saved volume settings FIRST (fastest operation)
        LoadVolumeSettings();
        
        // Apply loaded volumes to audio sources
        ApplyVolumeSettings();
        
        // Setup UI if available and sync with loaded values
        SetupUISliders();
        
        // Initialize music library (do this last)
        InitializeMusicLibrary();
        
        // Start playing music if we have tracks (this should be instant with streaming)
        if (musicLibrary.Length > 0)
        {
            StartPlayingMusic();
        }
        
        Debug.Log("AudioManager: Start() completed");
    }

    void ValidateMusicLibrary()
    {
        if (musicLibrary == null || musicLibrary.Length == 0)
        {
            Debug.LogWarning("AudioManager: No music tracks assigned!");
            return;
        }
        
        int validTracks = 0;
        for (int i = 0; i < musicLibrary.Length; i++)
        {
            if (musicLibrary[i] != null)
            {
                validTracks++;
                
                // Log potential performance issues
                if (musicLibrary[i].length > 300) // 5+ minutes
                {
                    Debug.LogWarning($"Track '{musicLibrary[i].name}' is very long ({musicLibrary[i].length:F1}s). Consider shorter tracks for better performance.");
                }
            }
        }
        
        Debug.Log($"AudioManager: {validTracks}/{musicLibrary.Length} valid music tracks loaded");
    }

    // New method to properly setup UI sliders with saved values
    void SetupUISliders()
    {
        // Find volume slider in the current scene if not assigned
        if (volumeSlider == null)
        {
            volumeSlider = FindSliderByName("VolumeSlider", "MusicSlider", "Music Volume", "Volume");
            Debug.Log($"AudioManager: Searching for volume slider in scene...");
        }
        
        if (volumeSlider != null)
        {
            Debug.Log($"AudioManager: Found volume slider '{volumeSlider.gameObject.name}' with current value {volumeSlider.value}");
            
            // Remove any existing listeners to prevent conflicts
            volumeSlider.onValueChanged.RemoveAllListeners();
            
            // Set slider to saved volume value WITHOUT triggering events
            volumeSlider.SetValueWithoutNotify(musicVolume);
            
            // Add listener for future changes
            volumeSlider.onValueChanged.AddListener(SetMusicVolume);
            
            Debug.Log($"AudioManager: Volume slider set to {musicVolume} and listener added");
        }
        else
        {
            Debug.Log("AudioManager: No volume slider found in current scene");
            // List all sliders for debugging
            Slider[] allSliders = FindObjectsByType<Slider>(FindObjectsSortMode.None);
            Debug.Log($"AudioManager: Found {allSliders.Length} sliders in scene:");
            foreach (var slider in allSliders)
            {
                Debug.Log($"  - {slider.gameObject.name} (value: {slider.value})");
            }
        }
    }

    // Helper method to find volume slider by common names
    Slider FindSliderByName(params string[] possibleNames)
    {
        Slider[] allSliders = FindObjectsByType<Slider>(FindObjectsSortMode.None);
        
        foreach (Slider slider in allSliders)
        {
            foreach (string name in possibleNames)
            {
                if (slider.gameObject.name.ToLower().Contains(name.ToLower()))
                {
                    return slider;
                }
            }
        }
        return null;
    }

    public void SetMasterVolume(float volume)
    {
        masterVolume = Mathf.Clamp01(volume);
        PlayerPrefs.SetFloat("MasterVolume", masterVolume);
        ApplyVolumeSettings();
    }

    public void SetMusicVolume(float volume)
    {
        Debug.Log($"AudioManager: SetMusicVolume called with {volume}. Previous volume: {musicVolume}");
        Debug.Log($"AudioManager: Call stack: {System.Environment.StackTrace}");
        
        musicVolume = Mathf.Clamp01(volume);
        PlayerPrefs.SetFloat("MusicVolume", musicVolume);
        PlayerPrefs.Save(); // Force save immediately
        ApplyMusicVolume();
        
        Debug.Log($"AudioManager: Volume saved to PlayerPrefs and applied: {musicVolume}");
    }

    public void SetSFXVolume(float volume)
    {
        sfxVolume = Mathf.Clamp01(volume);
        PlayerPrefs.SetFloat("SFXVolume", sfxVolume);
        ApplySFXVolume();
    }

    // Legacy method for compatibility
    public void SetVolume(float volume)
    {
        SetMusicVolume(volume);
    }

    private void LoadVolumeSettings()
    {
        float previousMusicVolume = musicVolume;
        
        masterVolume = PlayerPrefs.GetFloat("MasterVolume", 1f);
        musicVolume = PlayerPrefs.GetFloat("MusicVolume", 1f);
        sfxVolume = PlayerPrefs.GetFloat("SFXVolume", 1f);
        
        Debug.Log($"AudioManager: LoadVolumeSettings - Previous: {previousMusicVolume}, Loaded: {musicVolume}");
        Debug.Log($"AudioManager: PlayerPrefs MusicVolume key exists: {PlayerPrefs.HasKey("MusicVolume")}");
    }

    private void ApplyVolumeSettings()
    {
        ApplyMusicVolume();
        ApplySFXVolume();
    }

    private void ApplyMusicVolume()
    {
        if (musicSource != null)
        {
            musicSource.volume = masterVolume * musicVolume;
        }
    }

    private void ApplySFXVolume()
    {
        if (sfxSource != null)
        {
            sfxSource.volume = masterVolume * sfxVolume;
        }
    }

    // Method to play sound effects
    public void PlaySFX(AudioClip clip, float volumeScale = 1f)
    {
        if (sfxSource != null && clip != null)
        {
            sfxSource.PlayOneShot(clip, volumeScale * sfxVolume * masterVolume);
        }
    }

    // Method to change background music
    public void PlayMusic(AudioClip musicClip, bool loop = true)
    {
        if (musicSource != null && musicClip != null)
        {
            musicSource.clip = musicClip;
            musicSource.loop = loop;
            musicSource.Play();
        }
    }

    // Method to stop music
    public void StopMusic()
    {
        if (musicSource != null)
        {
            musicSource.Stop();
            isPlaying = false;
        }
    }

    // MUSIC LIBRARY METHODS
    
    void InitializeMusicLibrary()
    {
        if (musicLibrary.Length == 0)
        {
            Debug.LogWarning("AudioManager: No music tracks found in musicLibrary! Please assign your 7 music files.");
            return;
        }

        // Create shuffled playlist if shuffle is enabled
        if (shuffleMusic)
        {
            CreateShuffledPlaylist();
        }
        
        Debug.Log($"AudioManager: Music library initialized with {musicLibrary.Length} tracks. Shuffle: {shuffleMusic}");
    }

    void CreateShuffledPlaylist()
    {
        shuffledIndices = new List<int>();
        for (int i = 0; i < musicLibrary.Length; i++)
        {
            shuffledIndices.Add(i);
        }
        
        // Fisher-Yates shuffle algorithm
        for (int i = shuffledIndices.Count - 1; i > 0; i--)
        {
            int randomIndex = Random.Range(0, i + 1);
            int temp = shuffledIndices[i];
            shuffledIndices[i] = shuffledIndices[randomIndex];
            shuffledIndices[randomIndex] = temp;
        }
        
        shufflePosition = 0;
    }

    public void StartPlayingMusic()
    {
        if (musicLibrary.Length == 0 || musicSource == null)
            return;

        isPlaying = true;
        PlayCurrentTrack();
        
        // Start checking for track end
        StartCoroutine(TrackEndChecker());
    }

    void PlayCurrentTrack()
    {
        if (musicLibrary.Length == 0) return;

        int trackIndex = GetCurrentTrackIndex();
        
        if (trackIndex >= 0 && trackIndex < musicLibrary.Length)
        {
            AudioClip trackToPlay = musicLibrary[trackIndex];
            
            if (trackToPlay != null)
            {
                if (isFading)
                {
                    StartCoroutine(FadeToNewTrack(trackToPlay));
                }
                else
                {
                    musicSource.clip = trackToPlay;
                    // FIXED: Use the current volume settings instead of hardcoded values
                    musicSource.volume = musicVolume * masterVolume;
                    musicSource.loop = false; // We handle looping manually
                    musicSource.Play();
                }
                
                Debug.Log($"AudioManager: Now playing track {trackIndex + 1}/{musicLibrary.Length}: {trackToPlay.name} at volume {musicVolume * masterVolume}");
            }
        }
    }

    int GetCurrentTrackIndex()
    {
        if (shuffleMusic && shuffledIndices != null && shuffledIndices.Count > 0)
        {
            return shuffledIndices[shufflePosition];
        }
        else
        {
            return currentTrackIndex;
        }
    }

    IEnumerator TrackEndChecker()
    {
        while (isPlaying)
        {
            yield return new WaitForSeconds(0.5f); // Check every half second
            
            if (musicSource != null && !musicSource.isPlaying && !isFading)
            {
                // Track ended, play next
                PlayNextTrack();
            }
        }
    }

    public void PlayNextTrack()
    {
        if (musicLibrary.Length <= 1) return;

        if (shuffleMusic)
        {
            shufflePosition++;
            if (shufflePosition >= shuffledIndices.Count)
            {
                if (loopPlaylist)
                {
                    CreateShuffledPlaylist(); // Create new shuffle order
                }
                else
                {
                    StopMusic();
                    return;
                }
            }
        }
        else
        {
            currentTrackIndex++;
            if (currentTrackIndex >= musicLibrary.Length)
            {
                if (loopPlaylist)
                {
                    currentTrackIndex = 0;
                }
                else
                {
                    StopMusic();
                    return;
                }
            }
        }

        PlayCurrentTrack();
    }

    public void PlayPreviousTrack()
    {
        if (musicLibrary.Length <= 1) return;

        if (shuffleMusic)
        {
            shufflePosition--;
            if (shufflePosition < 0)
            {
                shufflePosition = shuffledIndices.Count - 1;
            }
        }
        else
        {
            currentTrackIndex--;
            if (currentTrackIndex < 0)
            {
                currentTrackIndex = musicLibrary.Length - 1;
            }
        }

        PlayCurrentTrack();
    }

    IEnumerator FadeToNewTrack(AudioClip newTrack)
    {
        isFading = true;
        float startVolume = musicSource.volume;

        // Fade out current track
        float fadeTimer = 0;
        while (fadeTimer < fadeDuration / 2)
        {
            fadeTimer += Time.deltaTime;
            musicSource.volume = Mathf.Lerp(startVolume, 0, fadeTimer / (fadeDuration / 2));
            yield return null;
        }

        // Change track
        musicSource.clip = newTrack;
        musicSource.Play();

        // Fade in new track
        fadeTimer = 0;
        float targetVolume = musicVolume * masterVolume;
        while (fadeTimer < fadeDuration / 2)
        {
            fadeTimer += Time.deltaTime;
            musicSource.volume = Mathf.Lerp(0, targetVolume, fadeTimer / (fadeDuration / 2));
            yield return null;
        }

        musicSource.volume = targetVolume;
        isFading = false;
    }

    // Public methods for UI controls
    public void ToggleShuffle()
    {
        shuffleMusic = !shuffleMusic;
        if (shuffleMusic)
        {
            CreateShuffledPlaylist();
        }
        Debug.Log($"AudioManager: Shuffle {(shuffleMusic ? "enabled" : "disabled")}");
    }

    public void TogglePlayPause()
    {
        if (musicSource != null)
        {
            if (musicSource.isPlaying)
            {
                musicSource.Pause();
                isPlaying = false;
            }
            else
            {
                musicSource.UnPause();
                isPlaying = true;
                StartCoroutine(TrackEndChecker());
            }
        }
    }

    // Get current track info for UI display
    public string GetCurrentTrackName()
    {
        int trackIndex = GetCurrentTrackIndex();
        if (trackIndex >= 0 && trackIndex < musicLibrary.Length && musicLibrary[trackIndex] != null)
        {
            return musicLibrary[trackIndex].name;
        }
        return "No Track";
    }

    public int GetCurrentTrackNumber()
    {
        return GetCurrentTrackIndex() + 1;
    }

    public int GetTotalTracks()
    {
        return musicLibrary.Length;
    }

    // Method to pause/unpause music
    public void PauseMusic(bool pause)
    {
        if (musicSource != null)
        {
            if (pause)
                musicSource.Pause();
            else
                musicSource.UnPause();
        }
    }
}