using System.Collections;
using System.Collections.Generic;
using Cysharp.Threading.Tasks;
using Gameplay;
using Gameplay.SubSystems;
using PhxhSDK;
using PhxhSDK.Res;
using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;
using UnityEngine.SceneManagement;

/// <summary>
/// 游戏场景的通用业务逻辑
/// </summary>
public class GameSceneHelper : Singlenton<GameSceneHelper>
{
    private Stack<(string, SceneHandle)> _uiViewSceneStack = new();
    private RenderTexture _rTexture;
    private Stack<(string, SceneHandle)> _rtSceneStack = new ();

    /// <summary>
    /// 打开UI预览场景，当某个UI需要单独渲染场景时使用(如PVP布阵，营地等)
    /// 该函数会使得预览场景中的相机只渲染UI场景内的物件
    /// 并处理了光照，全局GI，Volume，单一主相机
    /// </summary>
    /// <param name="scenePath"></param>
    /// <returns></returns>
    public async UniTask<SceneHandle> LoadSceneForUIView(string scenePath,
        LoadSceneMode loadSceneMode = LoadSceneMode.Additive)
    {
        var sceneHandle = await GameSceneManager.Instance.LoadSceneAsync(scenePath, loadSceneMode);
        if (sceneHandle == null)
        {
            return null;
        }

        if (loadSceneMode == LoadSceneMode.Additive)
        {
            if (_uiViewSceneStack.Count > 0)
            {
                //如果之前加载过UIView场景，则使得上一个场景不影响当前场景
                var lastUIViewSceneData = _uiViewSceneStack.Peek();
                SetSceneActiveForUIView(lastUIViewSceneData.Item2, false);
            }
        }
        else
        {
            _uiViewSceneStack.Clear();
        }

        SetSceneActiveForUIView(sceneHandle, true);

        _uiViewSceneStack.Push((scenePath, sceneHandle));
        return sceneHandle;
    }

    public async UniTask UnloadSceneForUIView()
    {
        if (_uiViewSceneStack.Count == 0)
        {
            DebugUtil.LogError($"没有加载过UIView场景");
            return;
        }

        var sceneData = _uiViewSceneStack.Pop();
        CameraManager.Instance.RevertMainCamera();
        await GameSceneManager.Instance.UnLoadSceneAsync(sceneData.Item1);
        if (_uiViewSceneStack.Count > 0)
        {
            var lastUIViewSceneData = _uiViewSceneStack.Peek();
            SetSceneActiveForUIView(lastUIViewSceneData.Item2, true);
        }
    }

    private void SetSceneActiveForUIView(SceneHandle sceneHandle,
        bool isActive)
    {
        var scene = sceneHandle.Scene;
        if (!scene.IsValid())
        {
            return;
        }
        var groundLayer = LayerMask.NameToLayer("Ground");
        var layerToSet = isActive ? LayerMask.NameToLayer("UIView") : LayerMask.NameToLayer("Default");
        var maskToSet = isActive ? LayerMask.GetMask("UIView", "Ground") : LayerMask.GetMask("Default", "Ground");
        //调整所有物品的层级

        var roots = scene.GetRootGameObjects();
        foreach (var root in roots)
        {
            //将所有gameObject设置为UIView层
            root.SetLayerEx(layerToSet, groundLayer);
        }

        var sceneMainCamera = sceneHandle.SceneMainCamera;
        if (sceneMainCamera != null)
        {
            var additionalData = sceneMainCamera.GetUniversalAdditionalCameraData();
            sceneMainCamera.cullingMask = maskToSet;
            //volume处理
            additionalData.volumeLayerMask = maskToSet;
        }

        //设置光源culling mask
        var lights = Object.FindObjectsOfType<Light>();
        foreach (var light in lights)
        {
            if (light.gameObject.scene != scene)
                continue;
            light.cullingMask = maskToSet;
        }

        if (isActive)
        {

            //切换全局GI
            SceneManager.SetActiveScene(scene);
            //切换主相机
            CameraManager.Instance.SwitchMainCamera(sceneMainCamera);

        }
    }

    public RenderTexture GetRenderTexture()
    {
        if (!_rTexture)
        {
            _CreateRt();
        }

        return _rTexture;
    }

    private void _CreateRt()
    {
        _rTexture = RenderTexturePool.Instance.Create("GameSceneHelper", Screen.width,
            Screen.height, RenderTexturePool.DEFAULT_DEPTH);
        _rTexture.name = "GameSceneHelper_rt";
    }

    private void _ReleaseRt()
    {
        if (_rTexture)
        {
            RenderTexturePool.Instance.Destroy(_rTexture);
            _rTexture = null;
        }
    }

    public SceneHandle GetCurrentUIViewScene()
    {
        if (_uiViewSceneStack.Count == 0)
            return null;
        return _uiViewSceneStack.Peek().Item2;
    }

    public async UniTask ChangeSceneForUIView(string scenePath, LoadSceneMode loadSceneMode = LoadSceneMode.Single)
    {
        if (_uiViewSceneStack.Count > 0)
        {
            var uiViewScene = _uiViewSceneStack.Pop();
            var sceneHandle = await GameSceneManager.Instance.LoadSceneAsync(scenePath, loadSceneMode);
            if (sceneHandle == null)
            {
                return;
            }
        
            _uiViewSceneStack.Push((scenePath, sceneHandle));
        }
        
    }

    public async UniTask<SceneHandle> LoadSceneForRt(string scenePath)
    {
        var sceneHandle = await GameSceneManager.Instance.LoadSceneAsync(scenePath, LoadSceneMode.Additive);
        if (sceneHandle == null)
        {
            return null;
        }
        
        var sceneCamera = sceneHandle.SceneMainCamera;
        var rTexture = GetRenderTexture();
        sceneCamera.targetTexture = rTexture;
        _rtSceneStack.Push((scenePath, sceneHandle));
        return sceneHandle;
    }

    public async UniTask UnLoadSceneForRt()
    {
        if (_rtSceneStack.Count > 0)
        {
            var item = _rtSceneStack.Pop();
            await GameSceneManager.Instance.UnLoadSceneAsync(item.Item1);
            _ReleaseRt();
        }
    }
}