using System.Collections.Generic;
using System.Linq;
using Cysharp.Threading.Tasks;
using PhxhSDK;
using UnityEngine;
using UnityEngine.AddressableAssets;
using UnityEngine.ResourceManagement.AsyncOperations;
using UnityEngine.ResourceManagement.ResourceProviders;
using UnityEngine.SceneManagement;

namespace Gameplay.SubSystems
{
    /// <summary>
    /// 游戏场景的底层逻辑
    /// </summary>
    public class GameSceneManager : Singlenton<GameSceneManager>
    {
        public class SceneHandle
        {
            public Scene Scene { get; private set; }

            public SceneHandle(Scene scene)
            {
                Scene = scene;
            }

            public Camera SceneMainCamera => CommonUtils.GetSceneRootComponent<Camera>(Scene);
        }

        private Dictionary<string, AsyncOperationHandle<SceneInstance>> _sceneOpDic = new();

        private string _lastSceneToBeUnload;

        private string GetPostProcessedScenePath(string scenePath) => PostProcessData.Instance[scenePath];

        public async UniTask<SceneHandle> LoadSceneAsync(string scenePath, LoadSceneMode mode = LoadSceneMode.Single)
        {
            scenePath = GetPostProcessedScenePath(scenePath);
            if (string.IsNullOrEmpty(scenePath))
            {
                DebugUtil.LogError($"ScenePath is null!");
                return null;
            }

            if (mode == LoadSceneMode.Single)
            {
                _sceneOpDic.Clear();
                _lastSceneToBeUnload = null;
            }

            if (!_sceneOpDic.TryGetValue(scenePath, out var op))
            {
                op = Addressables.LoadSceneAsync(scenePath, mode);
                _sceneOpDic.Add(scenePath, op);
            }

            await op;
            if (!string.IsNullOrEmpty(_lastSceneToBeUnload))
            {
                UnLoadSceneAsync(_lastSceneToBeUnload);
                _lastSceneToBeUnload = null;
            }
            
            return new(op.Result.Scene);
        }

        public async UniTask UnLoadSceneAsync(string scenePath)
        {
            scenePath = GetPostProcessedScenePath(scenePath);
            if (string.IsNullOrEmpty(scenePath))
            {
                DebugUtil.LogError($"ScenePath is null!");
                return;
            }

            if (!_sceneOpDic.TryGetValue(scenePath, out var op))
            {
                DebugUtil.LogError($"该场景没有被加载过 scenePath:{scenePath}");
                return;
            }

            if (_sceneOpDic.Count == 1)
            {
                //如果只剩下一个场景了，那么此次unload必然失败，要等到下一次load新场景后重新unload
                _lastSceneToBeUnload = scenePath;
            }
            else
            {
                _sceneOpDic.Remove(scenePath);
                await Addressables.UnloadSceneAsync(op);
            }
        }

        /// <summary>
        /// 返回场景加载的进度
        /// </summary>
        /// <param name="scenePath"></param>
        /// <returns>0-100的浮点数</returns>
        public float GetSceneLoadingProgress(string scenePath)
        {
            scenePath = GetPostProcessedScenePath(scenePath);
            if (_sceneOpDic.TryGetValue(scenePath, out var op))
            {
                return op.PercentComplete * 100;
            }

            return 0;
        }
    }
}