using System;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEngine.Rendering.Universal;

namespace PhxhSDK
{
    public class CameraManager : Singlenton<CameraManager>, IInitable
    {
        private Camera _mainCamera;

        private Stack<Camera> _usedMainCameraStack = new();

        private RenderTexture _defaultRenderTarget;

        public RenderTexture DefaultRenderTarget
        {
            get => _defaultRenderTarget;
            set
            {
                if (_defaultRenderTarget != value)
                {
                    _defaultRenderTarget = value;
                    _mainCamera.targetTexture = _defaultRenderTarget;
                }
            }
        }

        public event Action<Camera> AfterSwitchMainCamera;
        
        public Camera MainCamera => _mainCamera;

        public Camera UICamera
        {
            get { return UIRoot.Instance.UICamera; }
        }

        public Camera SkillCamera { get; private set; }

        public Camera CreateCamera(string name, string tag = null)
        {
            var go = new GameObject(name);
            var camera = go.AddComponent<Camera>();
            if (tag != null)
            {
                camera.tag = tag;
            }

            return camera;
        }

        public void DestroyCamera(Camera camera)
        {
            if (camera != null)
            {
                GameObject.Destroy(camera.gameObject);
            }
        }

        public void ReRenderAll()
        {
            foreach (var c in Camera.allCameras)
            {
                var oldEnabled = c.enabled;
                c.enabled = true;
                c.Render();
                c.enabled = oldEnabled;
            }
        }

        public void Init()
        {
            _mainCamera = Camera.main;
            if (_mainCamera == null)
            {
                CreateCamera("Main Camera", "MainCamera");
            }

            if (_mainCamera != null)
            {
                GameObject.DontDestroyOnLoad(MainCamera.gameObject);
            }

            SkillCamera = GameObject.Find("SkillCamera").GetComponent<Camera>();
        }

        public void SetMainCameraActive(bool isActive)
        {
            _mainCamera?.gameObject.SetActive(isActive);
        }

        public void SwitchMainCamera(Camera camera)
        {
            // DebugUtil.LogError("切换相机");
            if (camera == null || camera == _mainCamera)
                return;
            _usedMainCameraStack.Push(_mainCamera);
            _SwitchCameraPurely(camera);
        }

        public void RevertMainCamera()
        {
            // DebugUtil.LogError("还原相机");
            if (_usedMainCameraStack.Count == 0)
            {
                DebugUtil.LogError($"_usedMainCameraStack count is 0");
                return;
            }

            var _lastMainCamera = GetOutMostCameraInStack();

            if (_lastMainCamera == null)
            {
                DebugUtil.LogError($"相机栈中找不到旧的使用过的主相机");
                return;
            }
            
            _SwitchCameraPurely(_lastMainCamera);
        }

        private void _SwitchCameraPurely(Camera camera)
        {
            if (camera == null || _mainCamera == camera)
                return;
            var currCamera = _mainCamera;
            if (currCamera != null)
            {
                DeActiveMainCamera(currCamera);
            }

            _mainCamera = camera;

            ActiveMainCamera(_mainCamera);
            AfterSwitchMainCamera?.Invoke(_mainCamera);
        }

        private Camera GetOutMostCameraInStack()
        {
            Camera result = null;
            int popCount = 1;
            foreach (var camera in _usedMainCameraStack)
            {
                //可能会出现之前使用过的相机已经销毁的情况
                if (camera == null)
                    popCount++;
                else
                {
                    result = camera;
                    break;
                }
            }

            popCount = popCount > _usedMainCameraStack.Count ? _usedMainCameraStack.Count : popCount;
            for (int i = 0; i < popCount; i++)
            {
                _usedMainCameraStack.Pop();
            }
            
            return result;
        }

        private void ActiveMainCamera(Camera cam)
        {
            cam.gameObject.SetActive(true);
            cam.targetTexture = DefaultRenderTarget;
        }

        private void DeActiveMainCamera(Camera cam)
        {
            cam.gameObject.SetActive(false);
        }

        public void Release()
        {
            _usedMainCameraStack.Clear();
        }
    }
}