using Cysharp.Threading.Tasks;
using PhxhSDK;
using PhxhSDK.Res;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;

namespace Gameplay.SubSystems
{
    /// <summary>
    /// 游戏场景的底层逻辑
    /// </summary>
    public class GameSceneManager : Singlenton<GameSceneManager>
    {
        /// <summary>
        /// 空场景名
        /// </summary>
        private const string EMPTY_SCENE = "Empty.unity";
        /// <summary>
        /// 空场景路径
        /// </summary>
        private readonly string EMPTY_SCENE_PATH = $"Assets/Scenes/{EMPTY_SCENE}";
        /// <summary>
        /// 是否使用低品质场景
        /// </summary>
        private bool useLowScene;
        /// <summary>
        /// 场景加载器
        /// </summary>
        private readonly ISceneLoader sceneLoader;
        /// <summary>
        /// 加载中的场景列表
        /// </summary>
        private readonly HashSet<string> setLoadingScene = new();
        /// <summary>
        /// 等待卸载的场景
        /// </summary>
        private string waitUnloadScene;

        public GameSceneManager()
        {
            #if UNITY_EDITOR
            if (!Application.isPlaying)
            {
                sceneLoader = new SceneLoader_Fake();
                return;
            }
            #endif
            #if USE_YOO
            sceneLoader = new SceneLoader_YooAsset();
            #else
            _sceneLoader = new SceneLoader_Addressables();
            #endif
        }

        public void SetSceneLoadingSetting(bool isUseLowScene)
        {
            useLowScene = isUseLowScene;
        }

        public async UniTask<SceneHandle> LoadSceneAsync(string scenePath, LoadSceneMode mode = LoadSceneMode.Single)
        {
            string realScenePath = await GetPostProcessedScenePath(scenePath); // 真实加载路径

            if (string.IsNullOrEmpty(realScenePath))
            {
                DebugUtil.LogError($"转换后的场景路径为空!无法加载");
                return null;
            }

            if (!setLoadingScene.Add(realScenePath))
            {
                DebugUtil.LogError($"上一个相同场景还在加载中,请等待加载完成后再次加载:{realScenePath}");
                return null;
            }

            PhxhSDK.Res.SceneHandle sceneHandle = null;
            if (!sceneLoader.IsExistScene(realScenePath))
            {
                if (LoadSceneMode.Single == mode)
                {
                    // 先切换到Empty场景
                    await sceneLoader.LoadSceneAsync(EMPTY_SCENE_PATH, true);
                    await Resources.UnloadUnusedAssets();
                }

                sceneHandle = await sceneLoader.LoadSceneAsync(realScenePath, false, mode);
            }

            setLoadingScene.Remove(realScenePath);

            if (!string.IsNullOrEmpty(waitUnloadScene))
            {
                if (scenePath == waitUnloadScene)
                {
                    DebugUtil.Log($"等待卸载的场景和当前加载的场景一样,不卸载:{waitUnloadScene}");

                    waitUnloadScene = null;
                }
                else
                {
                    DebugUtil.Log($"卸载之前的场景:{waitUnloadScene}");

                    await UnLoadSceneAsync(waitUnloadScene);
                    waitUnloadScene = null;
                }
            }

            if (mode == LoadSceneMode.Single)
                await sceneLoader.UnAllLoadSceneAsync(realScenePath);

            return sceneHandle;
        }

        public async UniTask UnLoadSceneAsync(string scenePath)
        {
            string realScenePath = await GetPostProcessedScenePath(scenePath);

            if (string.IsNullOrEmpty(realScenePath))
            {
                DebugUtil.LogError($"卸载失败,路径:{realScenePath}");
                return;
            }

            await sceneLoader.UnLoadSceneAsync(realScenePath);
            /*if (null != scenePath && string.Empty != scenePath)
                waitUnloadScene = scenePath;*/
        }

        /// <summary>
        /// 返回场景加载的进度
        /// </summary>
        /// <param name="scenePath"></param>
        /// <returns>0-100的浮点数</returns>
        public async UniTask<float> GetSceneLoadingProgress(string scenePath)
        {
            var path = await GetPostProcessedScenePath(scenePath);
            return sceneLoader.GetSceneLoadingProgress(path);
        }

        /// <summary>
        /// 获取后处理场景路径
        /// </summary>
        /// <param name="scenePath"></param>
        /// <returns></returns>
        private async UniTask<string> GetPostProcessedScenePath(string scenePath)
        {
            if (scenePath.Equals(EMPTY_SCENE))
                return scenePath;

            if (useLowScene && !scenePath.Contains("_low"))
            {
                string lowScenePath = scenePath.Replace(".unity", "_low.unity");
                string realPath = await PostProcessData.GetPostProcessedPath(lowScenePath);
                if (null == realPath || string.Empty == realPath)
                    return await PostProcessData.GetPostProcessedPath(scenePath);
                else
                    return await PostProcessData.GetPostProcessedPath(lowScenePath);
            }
            
            return await PostProcessData.GetPostProcessedPath(scenePath);
        }
    }
}