using System;
using System.Collections;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using BITKit;
using BITKit.IO;
using Cysharp.Threading.Tasks;
using Microsoft.Extensions.Logging;
using UnityEngine;
using UnityEngine.Experimental.Rendering;
using UnityEngine.SceneManagement;
using YooAsset;

namespace Project.B.Map
{
    public class GameMapService : IGameMapService,IDisposable
    {
        public bool PreloadShaders { get; set; } = true;
        private readonly ILogger<GameMapService> _logger;
        private const string MenuScene = "map_menu";
        private readonly ValidHandle _isBusy = new();
        public TaskStatus TaskStatus
        {
            get => _taskStatus;
            private set
            {
                if (_taskStatus == value) return;
                OnTaskStatusChanged?.Invoke(_taskStatus, value);
                _taskStatus = value;
            }
        }
        private TaskStatus _taskStatus;

        private readonly CancellationTokenSource _cancellationTokenSource = new();

        public GameMapService(ILogger<GameMapService> logger)
        {
            _logger = logger;
        }

        public string CurrentMap { get;private set; }

        public UniTask<string> GetMapAsync()
        {
            return UniTask.FromResult(CurrentMap);
        }

        public async UniTask StartMapAsync(string map)
        {
            await _isBusy;

            using var _ = _isBusy.GetHandle();

            TaskStatus = TaskStatus.Running;

            SceneHandle handle = null;

            ResourcePackage mapPackage = null;

            CurrentMap = map;
            
            await OnMapChange.UniTaskFunc(map);
            
            await UniTask.NextFrame();

            foreach (var resourcePackage in YooAssetUtils.RegisteredResourcePackages)
            {
                if (YooAssetModHelper.PackagesManifestDictionary[resourcePackage.PackageName].Contains(map) is false)
                    continue;

                var assetInfo = resourcePackage.GetAssetInfo(map);

                mapPackage = resourcePackage;
                handle = resourcePackage.LoadSceneAsync(assetInfo.AssetPath);
            }

            if (handle is null)
            {
                throw new Exception($"找不到地图:{map}");
            }

       

            while (handle.IsDone is false && handle.IsValid)
            {
                await UniTask.NextFrame();
                OnMapLoadingProgress?.Invoke(Guid.Empty, handle.Progress, "正在加载地图");
                //if(_cancellationTokenSource.IsCancellationRequested)return;
            }



            if (PreloadShaders)
            {
                OnMapLoadingProgress?.Invoke(Guid.Empty, 1, "地图加载完成,正在查找着色器...");

                if (YooAssetModHelper.PackagesManifestDictionary[mapPackage.PackageName].Contains("MyShaderVariants"))
                {
                    var shaderAssetInfo = mapPackage.GetAssetInfo("MyShaderVariants");

                    var hashset = new HashSet<Material>();

                    _logger.LogInformation("已找到着色器,加载中...");
                    OnMapLoadingProgress?.Invoke(Guid.Empty, 1, "找到着色器,正在初始化...");
                    var assetHandle = mapPackage.LoadAssetSync(shaderAssetInfo);
                    var shader = (ShaderVariantCollection)assetHandle.AssetObject;
                    shader.WarmUp();


                    foreach (var gameObject in handle.SceneObject.GetRootGameObjects())
                    {
                        foreach (var meshRenderer in gameObject.GetComponentsInChildren<MeshRenderer>())
                        {
                            foreach (var material in meshRenderer.sharedMaterials)
                            {
                                hashset.Add(material);
                            }
                        }

                        foreach (var terrain in gameObject.GetComponentsInChildren<Terrain>())
                        {
                            hashset.Add(terrain.materialTemplate);
                        }
                    }

                    foreach (var material in hashset)
                    {
                        if (!material) continue;
                        if (material.shader is null) continue;
                        material.shader = Shader.Find(material.shader.name);
                    }


                    _logger.LogInformation($"着色器加载完成,有Shader{shader.shaderCount}个,Variant:{shader.variantCount}个");
                }
                else
                {
                    _logger.LogInformation("未找到着色器,跳过加载...");
                }

                OnMapLoadingProgress?.Invoke(Guid.Empty, 1, "着色器预热完成,准备就绪");
                
                TaskStatus = TaskStatus.RanToCompletion;

                await OnMapChanging.UniTaskFunc(map);

                OnMapChanged?.Invoke(Guid.Empty, CurrentMap);
            }
        }

        public async UniTask StopMapAsync()
        {
            await _isBusy;
            using var _ = _isBusy.GetHandle();
            
            TaskStatus = TaskStatus.WaitingForActivation;
            //if(_cancellationTokenSource.IsCancellationRequested)return;
            await YooAssets.LoadSceneAsync(MenuScene);
            
            OnMapChanged?.Invoke(Guid.Empty, string.Empty);
        }

        public event Action<TaskStatus, TaskStatus> OnTaskStatusChanged;
        public event Func<string, UniTask> OnMapChange;
        public event Func<string, UniTask> OnMapChanging;
        public event Action<Guid, string> OnMapChanged;
        public event Action<Guid, float, string> OnMapLoadingProgress;

        public void Dispose()
        {
            _cancellationTokenSource.Cancel();
        }
    }

}