using System;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEngine.Audio;

namespace OCES.Audio
{
    public class AudioSystem : MonoBehaviour
    {
        public static AudioSystem Instance { get; private set; }

        const string k_audioConfigPath = "AudioData";
        const string k_audioResourcePath = "Audios";

        AudioScheduler m_scheduler;
        MusicSystem m_musicSystem;

        AudioObjectConfig m_audioObjects;
        AudioGroupConfig m_groups;
        AudioMixer m_mixer;

        // ─────────────────────────────────────────────
        // 公开接口
        // ─────────────────────────────────────────────

        public void Play(AudioObject audioObject)
        {
            this.m_scheduler.TryPlay(audioObject);
        }

        public void Play(int audioId)
        {
            AudioObject obj = this.m_audioObjects.QueryById((uint)audioId);
            if (obj != null)
                this.m_scheduler.TryPlay(obj);
        }

        public void Play(string audioName)
        {
            // TODO: 按文件名播放
        }

        /// <summary>
        /// 更新游戏状态，驱动音乐与环境音系统切换。
        /// 调用示例：AudioSystem.Instance.SetState(GameState.Game);
        /// </summary>
        public void SetState<TEnum>(TEnum state) where TEnum : Enum
        {
            this.m_musicSystem.OnStateChanged(state);
        }

        // ─────────────────────────────────────────────
        // 初始化
        // ─────────────────────────────────────────────

        void Awake()
        {
            if ((bool)Instance && Instance != this)
            {
                Destroy(gameObject);
                return;
            }
            Instance = this;
            DontDestroyOnLoad(gameObject);

            this.m_mixer        = Resources.Load<AudioMixer>("Audios/Master");
            
            // ── SFX 调度器 ──
            this.m_scheduler    = gameObject.AddComponent<AudioScheduler>();
            this.m_audioObjects = AudioConfigLoader.Load<AudioObjectConfig>($"{k_audioConfigPath}/AudioObject");
            this.m_groups       = AudioConfigLoader.Load<AudioGroupConfig>($"{k_audioConfigPath}/AudioGroup");
            this.m_scheduler.Initialize(this.m_groups, this.m_mixer);

            // ── 音乐与环境音系统 ──
            var segments            = AudioConfigLoader.Load<MusicSegmentConfig>($"{k_audioConfigPath}/MusicSegment");
            var containers          = AudioConfigLoader.Load<MusicContainerConfig>($"{k_audioConfigPath}/MusicContainer");
            var musicPaths          = AudioConfigLoader.Load<MusicPathConfig>($"{k_audioConfigPath}/MusicPath");
            var ambiencePaths       = AudioConfigLoader.Load<AmbiencePathConfig>($"{k_audioConfigPath}/AmbiencePath");
            var musicTransitions    = AudioConfigLoader.Load<MusicTransitionConfig>($"{k_audioConfigPath}/MusicTransition");
            var ambienceTransitions = AudioConfigLoader.Load<AmbienceTransitionConfig>($"{k_audioConfigPath}/AmbienceTransition");

            // MusicSystem 需要运行协程，作为 MonoBehaviour 挂载在同一 GameObject 上
            this.m_musicSystem = gameObject.AddComponent<MusicSystem>();

            // AudioSourcePool 由 MusicSystem 独占一个子节点，与 SFX pool 隔离
            GameObject musicPoolRoot = new("MusicSourcePool");
            musicPoolRoot.transform.SetParent(transform, false);
            AudioMixerGroup musicGroup = this.m_mixer.FindMatchingGroups("Master/Music")[0];
            AudioSourcePool musicPool = new(musicPoolRoot.transform, musicGroup);

            GameObject ambiencePoolRoot = new("AmbienceSourcePool");
            musicPoolRoot.transform.SetParent(transform, false);
            AudioMixerGroup ambienceGroup = this.m_mixer.FindMatchingGroups("Master/SFX/Ambience")[0];
            AudioSourcePool ambiencePool = new(ambiencePoolRoot.transform, ambienceGroup);

            this.m_musicSystem.Initialize(
                segments,
                containers,
                musicPaths,
                ambiencePaths,
                musicTransitions,
                ambienceTransitions,
                musicPool,
                ambiencePool);
            
            // ── 注册 StateGroup ──
            // 在此处注册所有游戏状态 enum，TypeId 需与策划表中填写的数字一致
            // 示例（请根据实际 enum 修改）：
            // StateGroupRegistry.Register<GameState>(1);
            // StateGroupRegistry.Register<Theme>(2);
            StateGroupRegistry.Register<GameState>(1);

            // ── 启动默认音乐与环境音 ──
            // 触发一次初始状态，让音乐系统从默认状态开始匹配
            SetState(GameState.Home);
        }
    }

    static class AudioConfigLoader
    {
        public static Dictionary<uint, T> Load<T>(string path, Func<T, uint> keySelector)
        {
            string json = System.IO.File.ReadAllText(path);
            var wrapper = JsonUtility.FromJson<AudioObjectArrayWrapper<T>>(json);
            return wrapper.AudioObjects.ToDictionary(keySelector);
        }

        public static T Load<T>(string tableName) where T : IBinarySerializable, new()
        {
            TextAsset bytes = Resources.Load<TextAsset>(tableName);
            if (!bytes)
                Debug.LogError($"未找到表 {tableName}");
            IBinarySerializable data = new T();
            bool readOk = FileManager.ReadBinaryDataFromBytes(bytes.bytes, ref data);
            if (readOk)
                return (T)data;
            Debug.LogError($"{tableName} 解析出错，类型 {typeof(T)}");
            return default;
        }

        class AudioObjectArrayWrapper<T>
        {
            public T[] AudioObjects;
        }
    }
}