using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using UnityEngine;
using UnityEngine.AddressableAssets;
using UnityEngine.AddressableAssets.ResourceLocators;
using UnityEngine.ResourceManagement.AsyncOperations;
using UnityEngine.ResourceManagement.ResourceLocations;

namespace BrewMonster.Scripts
{
    public class AddressableManager : MonoSingleton<AddressableManager>
    {
        private bool _isInitialized = false;

        private Dictionary<string, AsyncOperationHandle<GameObject>> _loadedAssets = new();
        public event Action OnDispose;

        protected override void Initialize()
        {
            base.Initialize();
            _isInitialized = false;
            Addressables.InitializeAsync().Completed += OnInitializeComplete;
        }   

        void OnInitializeComplete(AsyncOperationHandle<IResourceLocator> handle)
        {
            if (handle.Status == AsyncOperationStatus.Succeeded)
            {
                _isInitialized = true;
                BMLogger.Log($"AddressableManager: Initialized");
            }
            else
            {
                // print out the error
                BMLogger.LogError($"AddressableManager: Failed to initialize: {handle.OperationException?.Message} {handle.OperationException?.StackTrace}");
            }
        }

        /// <summary>
        /// Load an asset asynchronously. The address should look like this: "models/npcs/npc/魅灵首领/魅灵首领/魅灵首领.prefab"
        /// </summary>
        /// <returns></returns>
        public async Task<GameObject> LoadPrefabAsync(string assetPath)
        {
            if (_loadedAssets.ContainsKey(assetPath))
            {
                return _loadedAssets[assetPath].Result;
            }

            try
            {
                var handle = Addressables.LoadAssetAsync<GameObject>(assetPath);
                await handle.Task;
                _loadedAssets[assetPath] = handle;
                return handle.Result;
            }
            catch (System.Exception e)
            {
                BMLogger.LogError(e.StackTrace);
                return null;
            }
        }

        /// <summary>
        /// When the asset is no longer needed, call this method to unload it.
        /// </summary>
        /// <param name="assetPath">The asset path used when loading the asset</param>
        public void ReleaseAsset(string assetPath)
        {
            if (_loadedAssets.TryGetValue(assetPath, out var handle))
            {
                if (handle.IsValid())
                {
                    Addressables.Release(handle);
                }
                _loadedAssets.Remove(assetPath);
                BMLogger.Log($"AddressableManager: Released asset: {assetPath}");
            }
            else
            {
                BMLogger.LogWarning($"AddressableManager: Asset not found in cache: {assetPath}");
            }
        }

        /// <summary>
        /// Release a specific asset by its handle directly.
        /// </summary>
        /// <param name="handle">The async operation handle to release</param>
        public void ReleaseAsset(AsyncOperationHandle<GameObject> handle)
        {
            if (handle.IsValid())
            {
                Addressables.Release(handle);
            }
        }

        /// <summary>
        /// Release all loaded assets from the cache.
        /// </summary>
        public void ReleaseAllAssets()
        {
            foreach (var kvp in _loadedAssets)
            {
                if (kvp.Value.IsValid())
                {
                    Addressables.Release(kvp.Value);
                }
            }
            _loadedAssets.Clear();
            BMLogger.Log("AddressableManager: Released all assets");
        }

        /// <summary>
        /// Check if an asset is currently loaded in the cache.
        /// </summary>
        /// <param name="assetPath">The asset path to check</param>
        /// <returns>True if the asset is loaded</returns>
        public bool IsAssetLoaded(string assetPath)
        {
            return _loadedAssets.ContainsKey(assetPath) && _loadedAssets[assetPath].IsValid();
        }

        /// <summary>
        /// Get the count of currently loaded assets.
        /// </summary>
        public int LoadedAssetCount => _loadedAssets.Count;

        private void OnDestroy()
        {
            OnDispose?.Invoke();
            ReleaseAllAssets();
        }
    }
}