using UnityEngine;
using UnityEngine.SceneManagement;
using System.Collections;

public class BGMManager : MonoBehaviour
{
    public static BGMManager instance;

    public AudioSource audioSource;

    [Header("BGM Clips")]
    public AudioClip menuBGM;
    public AudioClip bab1BGM;
    public AudioClip bab2BGM;
    public AudioClip bab3BGM;
    public AudioClip bab4BGM;
    public AudioClip bab5BGM;

    [Header("Fade Settings")]
    public float fadeDuration = 1.0f;

    private float musicVolume = 0.4f; // dari slider
    Coroutine fadeCoroutine;

    void Awake()
    {
        if (instance != null && instance != this)
        {
            Destroy(gameObject);
            return;
        }

        instance = this;
        DontDestroyOnLoad(gameObject);

        if (audioSource == null)
            audioSource = GetComponent<AudioSource>();

        audioSource.loop = true;

        LoadVolume();

        SceneManager.sceneLoaded += OnSceneLoaded;
    }

    void OnSceneLoaded(Scene scene, LoadSceneMode mode)
    {
        switch (scene.name)
        {
            case "MainMenu":
            case "StorySelect":
                ChangeMusic(menuBGM);
                break;
            case "Bab_1":
                ChangeMusic(bab1BGM);
                break;
            case "Bab_2":
                ChangeMusic(bab2BGM);
                break;
            case "Bab_3":
                ChangeMusic(bab3BGM);
                break;
            case "Bab_4":
                ChangeMusic(bab4BGM);
                break;
            case "Bab_5":
                ChangeMusic(bab5BGM);
                break;
        }
    }

    public void SetMusicVolume(float value)
    {
        musicVolume = value;
        audioSource.volume = value;
        PlayerPrefs.SetFloat("MUSIC_VOLUME", value);
    }

    void LoadVolume()
    {
        musicVolume = PlayerPrefs.GetFloat("MUSIC_VOLUME", 0.4f);
        audioSource.volume = musicVolume;
    }

    public void ChangeMusic(AudioClip newClip)
    {
        if (newClip == null || audioSource == null) return;
        if (audioSource.clip == newClip) return;

        if (fadeCoroutine != null)
            StopCoroutine(fadeCoroutine);

        fadeCoroutine = StartCoroutine(FadeChange(newClip));
    }

    IEnumerator FadeChange(AudioClip newClip)
    {
        float startVolume = audioSource.volume;

        float t = 0f;
        while (t < fadeDuration)
        {
            t += Time.unscaledDeltaTime;
            audioSource.volume = Mathf.Lerp(startVolume, 0f, t / fadeDuration);
            yield return null;
        }

        audioSource.volume = 0f;

        audioSource.clip = newClip;
        audioSource.Play();

        t = 0f;
        while (t < fadeDuration)
        {
            t += Time.unscaledDeltaTime;
            audioSource.volume = Mathf.Lerp(0f, musicVolume, t / fadeDuration);
            yield return null;
        }

        audioSource.volume = musicVolume;
    }
}