using System;
using System.Collections.Generic;
using PhxhSDK;
using UnityEngine;
using PlayState = PhxhSDK.PlayState;

/// <summary>
/// 音频播放器
/// 功能：异步加载、播放控制、3D空间音效、淡入淡出效果
/// 实现接口：IAudioPlayer, IAudioSpatial, IAudioFade, IDisposable
/// </summary>
public class AudioPlayer : IAudioPlayer, IAudioSpatial, IAudioFade, IDisposable
{
    #region Static - ID Generation & Resource Tracking
    
    private static int _audioIDCounter;
    private static Dictionary<string, int> _loadedAssetPaths = new();
    
    /// <summary>
    /// 生成唯一的 AudioID
    /// </summary>
    public static int GenAudioID() => ++_audioIDCounter;

    /// <summary>
    /// 重置 AudioID 计数器
    /// </summary>
    public static void ReleaseAudioIDs() => _audioIDCounter = 0;

    /// <summary>
    /// 释放所有已加载的资源
    /// </summary>
    public static void ReleaseLoadedAssets()
    {
        foreach (var kv in _loadedAssetPaths)
        {
            var key = kv.Key;
            var count = kv.Value;
            while (count > 0)
            {
                AssetManager.Instance.Unload(key, false, true);
                --count;
            }
        }
        _loadedAssetPaths.Clear();
    }
    
    #endregion
    
    #region Fields
    
    // Unity 组件
    private readonly GameObject _rootGo;
    private readonly AudioSource _audioSource;
    private AudioClip _clip;
    
    // 状态
    private PlayState _playState;
    private readonly int _audioID;
    private EAudioType _eAudioType;
    private bool _loop;
    
    /// <summary>
    /// 当前播放的音频配置 key（用于停止池复用）
    /// 由 AudioManager 在播放前设置
    /// </summary>
    public string CurrentPlayingKey { get; set; }
    
    // 音量控制
    private float _targetVolume = 1f;
    private float _normalizeVolume = 1f;
    
    // 效果控制器
    private readonly AudioFadeEffect _fadeEffect;
    private readonly AudioSpatialController _spatialController;
    
    #endregion
    
    #region Properties
    
    // IAudioPlayer 接口属性
    public int AudioId => _audioID;
    public PlayState State => _playState;
    public bool IsPlaying => _playState == PlayState.Playing;
    public AudioClip Clip => _clip;
    
    /// <summary>
    /// 音量（0-1），返回目标音量（非实际音量）
    /// </summary>
    public float Volume
    {
        get => _targetVolume;
        set => _targetVolume = Mathf.Clamp01(value);
    }
    
    /// <summary>
    /// 音频类型（Music/Sound/Speak），只读，在构造时确定
    /// </summary>
    public EAudioType AudioType => _eAudioType;
    
    /// <summary>
    /// 是否循环播放
    /// </summary>
    public bool Loop
    {
        get => _loop;
        set
        {
            _loop = value;
            if (_audioSource != null)
                _audioSource.loop = value;
        }
    }
    
    // 内部属性（仅供 Manager 层访问）
    internal GameObject RootGo => _rootGo;
    
    #endregion
    
    #region Constructor & Initialization

    /// <summary>
    /// 构造音频播放器
    /// </summary>
    /// <param name="eAudioType">音频类型</param>
    /// <param name="rootGo">挂载的 GameObject</param>
    /// <param name="followTarget">可选的跟随目标（自动启用3D音效）</param>
    public AudioPlayer(EAudioType eAudioType, GameObject rootGo, GameObject followTarget = null)
    {
        _audioID = GenAudioID();
        _eAudioType = eAudioType;
        _rootGo = rootGo;
        _audioSource = GetOrAddAudioSource(rootGo);
        _audioSource.volume = AudioVolumeSettings.Instance.GlobalVolume;
        
        // 初始化效果控制器
        _fadeEffect = new AudioFadeEffect(
            fadeInDuration: AudioConstant.DefaultFadeInDuration, 
            fadeOutDuration: AudioConstant.DefaultFadeOutDuration);
        
        _spatialController = new AudioSpatialController(_rootGo.transform, _audioSource);
        
        // 如果指定了跟随对象，设置跟随
        if (followTarget != null)
        {
            _spatialController.SetFollowTarget(followTarget);
        }
    }

    private AudioSource GetOrAddAudioSource(GameObject go)
    {
        var source = go.GetComponent<AudioSource>();
        if (!source)
        {
            source = go.AddComponent<AudioSource>();
        }
        return source;
    }

#endregion

    #region Lifecycle & Update

    public void Update(float dt)
    {
        if (_audioSource == null || _clip == null)
            return;

        // 更新淡入淡出效果
        bool shouldStop = _fadeEffect.Update(dt);
        
        // 更新音量
        if (_playState == PlayState.Playing || _audioSource.isPlaying)
        {
            UpdateVolume();
        }

        // 暂停状态不更新
        if (_playState == PlayState.Paused)
            return;
        
        // 更新空间位置跟随
        if (_playState == PlayState.Playing)
        {
            _spatialController.Update();
        }

        // 检查是否应该停止（播放结束或淡出完成）
        if (IsPlaybackEnded() || shouldStop || _playState == PlayState.Stopped)
        {
            if (_playState == PlayState.Loading)
                return;

            Stop();
        }
    }

    /// <summary>
    /// 判断播放是否已结束
    /// 只有非循环音频在播放完成后才返回 true
    /// </summary>
    private bool IsPlaybackEnded()
    {
        if (_audioSource == null || _clip == null)
            return false;
        
        // 循环音频永远不会结束
        if (_loop)
            return false;
        
        // 只有同时满足以下条件才算结束：
        // 1. 不在播放状态（!isPlaying）
        // 2. 播放时间已到末尾（time >= length）
        // 3. 状态不是 Paused（暂停不算结束）
        // 4. 状态不是 Loading（加载中不算结束）
        return !_audioSource.isPlaying 
            && _audioSource.time >= _clip.length 
            && _playState != PlayState.Paused
            && _playState != PlayState.Loading;
    }
    
    #endregion
    
    #region Playback Control

    /// <summary>
    /// 播放音频（需要先设置 Clip）
    /// </summary>
    public void Play()
    {
        if (_clip == null)
        {
            DebugUtil.LogError("AudioPlayer: Cannot play without clip");
            return;
        }
        
        _playState = PlayState.Playing;
        _fadeEffect.Stop();
        _targetVolume = 1f;
        _audioSource.Play();
        NotifyPlayStarted();
    }

    /// <summary>
    /// 暂停播放
    /// </summary>
    public void Pause()
    {
        if (_audioSource != null)
        _audioSource.Pause();
        _playState = PlayState.Paused;
    }

    /// <summary>
    /// 恢复播放
    /// </summary>
    public void Resume()
    {
        if (_audioSource != null)
        _audioSource.UnPause();
        _playState = PlayState.Playing;
    }

    /// <summary>
    /// 停止播放
    /// </summary>
    public void Stop()
    {
        _fadeEffect.Stop();
        
        if (IsPlaybackEnded())
        {
            _playState = PlayState.Stopped;
            return;
        }

        if (_audioSource != null)
        {
            _audioSource.Stop();
        }
        _playState = PlayState.Stopped;
    }

    /// <summary>
    /// 释放资源（销毁 GameObject）
    /// </summary>
    public void Dispose()
    {
        Stop();
        
        if (_rootGo != null)
        {
            UnityEngine.Object.Destroy(_rootGo);
        }
    }

#endregion

    #region Async Loading & Play

    /// <summary>
    /// 异步加载并播放音频（不带淡入淡出）
    /// </summary>
    /// <param name="path">音频资源路径</param>
    public void LoadAndPlay(string path)
    {
        _playState = PlayState.Loading;
        LoadAndPlayInternal(path, useFade: false);
    }

    /// <summary>
    /// 异步加载并播放音频（带淡入淡出效果）
    /// </summary>
    /// <param name="path">音频资源路径</param>
    /// <param name="fadeInTime">淡入时长（秒）</param>
    /// <param name="fadeOutTime">淡出时长（秒）</param>
    public void LoadAndPlayWithFade(string path, 
        float fadeInTime = AudioConstant.DefaultFadeInDuration, 
        float fadeOutTime = AudioConstant.DefaultFadeOutDuration)
    {
        _playState = PlayState.Loading;
        LoadAndPlayInternal(path, useFade: true, fadeInTime, fadeOutTime);
    }

    /// <summary>
    /// 统一的异步加载和播放逻辑
    /// </summary>
    private async void LoadAndPlayInternal(string path, bool useFade, 
        float fadeInTime = AudioConstant.DefaultFadeInDuration, 
        float fadeOutTime = AudioConstant.DefaultFadeOutDuration)
    {
        // 1. 异步加载音频资源
        _clip = await AssetManager.Instance.LoadAssetAsync<AudioClip>(path, null, true);
        
        // 2. 跟踪已加载的资源（用于后续卸载）
        TrackLoadedAsset(path);
        
        // 3. 加载失败处理
        if (_clip == null)
        {
            _playState = PlayState.Stopped;
            return;
        }
        
        // 4. 设置 AudioSource
        _audioSource.clip = _clip;
        _targetVolume = 1f;
        
        // 5. 根据是否需要淡入淡出设置音量
        if (useFade)
        {
            _fadeEffect.FadeInDuration = fadeInTime;
            _fadeEffect.FadeOutDuration = fadeOutTime;
            _fadeEffect.StartFadeIn();
            _audioSource.volume = 0f;
        }
        else
        {
            _fadeEffect.Stop();
        }
        
        // 6. 开始播放
        _audioSource.Play();
        _playState = PlayState.Playing;
        
        // 7. 通知 Manager
        NotifyPlayStarted();
    }
    
    /// <summary>
    /// 跟踪已加载的资源（用于引用计数）
    /// </summary>
    private void TrackLoadedAsset(string path)
    {
        if (_loadedAssetPaths.ContainsKey(path))
            ++_loadedAssetPaths[path];
        else
            _loadedAssetPaths.TryAdd(path, 1);
    }
    
    /// <summary>
    /// 通知外部播放已开始（触发事件）
    /// </summary>
    private void NotifyPlayStarted()
    {
        // 空方法，保留接口以避免破坏现有调用
    }
    
    #endregion
    
    #region Volume & Configuration

    /// <summary>
    /// 设置音量缩放系数（来自配置表的音量调整值）
    /// </summary>
    /// <param name="scale">音量缩放系数，默认1.0，必须为非负数</param>
    public void SetVolumeScale(float scale = 1f)
    {
        _normalizeVolume = Mathf.Max(0f, scale);
    }

    /// <summary>
    /// 设置音频片段（仅供 Manager 层使用）
    /// </summary>
    internal void SetClip(AudioClip clip)
    {
        _clip = clip;
        if (_audioSource != null)
            _audioSource.clip = clip;
    }
    
    /// <summary>
    /// 统一的音量更新方法
    /// 最终音量 = 淡入淡出系数 × 类型音量 × 全局音量 × 目标音量 × 归一化音量
    /// </summary>
    private void UpdateVolume()
    {
        var settings = AudioVolumeSettings.Instance;
        var fadeValue = _fadeEffect.FadeValue;
        
        // 根据音频类型选择对应的音量系数
        float typeVolume = this.AudioType switch
        {
            EAudioType.Music => settings.MusicVolume,
            EAudioType.Sound => settings.SoundVolume,
            EAudioType.Speak => settings.SpeakVolume,
            _ => 1f
        };
        
        _audioSource.volume = fadeValue * typeVolume * settings.GlobalVolume * _targetVolume * _normalizeVolume;
    }
    
    #endregion
    
    #region Spatial Audio (3D)

    /// <summary>
    /// 设置是否启用 3D 空间音效
    /// </summary>
    public void SetIs3D(bool is3D = false)
    {
        if (is3D)
            _spatialController.Enable3D();
        else
            _spatialController.Disable3D();
    }

    /// <summary>
    /// 设置跟随对象（自动启用 3D）
    /// </summary>
    public void SetFollowTarget(GameObject target = null)
    {
        _spatialController.SetFollowTarget(target);
    }

    /// <summary>
    /// 设置静态位置（自动启用 3D）
    /// </summary>
    public void SetPosition(Vector3 position)
    {
        _spatialController.SetStaticPosition(position, enable3D: true);
    }

#endregion

    #region Fade Effects
    
    /// <summary>
    /// 淡入播放（需要先设置 Clip）
    /// </summary>
    public void PlayWithFadeIn(float duration = AudioConstant.DefaultFadeInDuration)
    {
        if (_clip == null)
        {
            DebugUtil.LogError("AudioPlayer: Cannot PlayWithFadeIn without clip");
            return;
        }
        
        _fadeEffect.FadeInDuration = duration;
        _fadeEffect.StartFadeIn();
        
        _playState = PlayState.Playing;
        _audioSource.volume = 0f;
        _audioSource.Play();
        NotifyPlayStarted();
    }
    
    /// <summary>
    /// 淡出停止（淡出完成后自动调用 Stop）
    /// </summary>
    public void StopWithFadeOut(float duration = AudioConstant.DefaultFadeOutDuration)
    {
        _fadeEffect.StartFadeOut(duration);
    }

#endregion
    
    #region Query & Debug

    /// <summary>
    /// 获取当前播放时间（秒）
    /// </summary>
    public float GetPlaybackTime() => _audioSource ? _audioSource.time : -1f;
    
    /// <summary>
    /// 获取音频频谱数据（用于可视化）
    /// </summary>
    public void GetSpectrumData(float[] spectrums)
    {
        if (_audioSource != null)
        {
            _audioSource.GetSpectrumData(spectrums, 0, FFTWindow.Blackman);
        }
    }
    
    #endregion
}