using System;
using System.Collections.Generic;
#if UNITY_EDITOR
using UnityEditor;
#endif
using UnityEngine;
using UnityEngine.Rendering;

namespace Assets.ThoMagic.Renderer
{
    public class FrameRenderer
    {
        [RuntimeInitializeOnLoadMethod]
        public static void Initialize()
        {
#if UNITY_EDITOR
            AssemblyReloadEvents.beforeAssemblyReload += AssemblyReloadEvents_beforeAssemblyReload;
#endif
            RendererPool.RemoveDestroyedCameras();
            RendererPool.Initialize();
            Camera.onPreCull -= RenderCamera;            
            Camera.onPreCull += RenderCamera;
            RenderPipelineManager.beginContextRendering -= OnBeginContextRendering;
            RenderPipelineManager.beginContextRendering += OnBeginContextRendering;            
        }

        private static void AssemblyReloadEvents_beforeAssemblyReload()
        {
            RendererPool.Destroy();
        }

        private static void OnBeginContextRendering(
          ScriptableRenderContext context,
          List<Camera> cameras)
        {
            RendererPool.BuildBuffers();
            RendererPool.RemoveDestroyedCameras();
            foreach(var camera in cameras)
            {
                if (!CameraIsSupported(camera))
                {
                    RendererPool.RemoveCamera(camera.GetHashCode());
                }
                else
                {
                    CameraRenderer cameraRenderer = RendererPool.GetCamera(RendererPool.RegisterCamera(camera));
                    try
                    {
                        cameraRenderer.Render();
                    }
                    catch (Exception ex)
                    {
                        Debug.LogException(ex);
                    }
                }
            }
        }

        private static void RenderCamera(Camera camera)
        {
            if (camera == null)
                throw new NullReferenceException(nameof(camera));

            if (!CameraIsSupported(camera))
            {
                RendererPool.RemoveCamera(camera.GetHashCode());
            }
            else
            {
                RendererPool.BuildBuffers();
                RendererPool.RemoveDestroyedCameras();
                int cameraId = RendererPool.RegisterCamera(camera);
                try
                {
                    RendererPool.GetCamera(cameraId)?.Render();
                }
                catch (Exception ex)
                {
                    Debug.LogException(ex);
                }
            }
        }

        private static bool CameraIsSupported(Camera camera)
        {
            IInstanceRenderSettings instanceRenderSettings;
            return (Application.isPlaying || camera.cameraType != CameraType.Preview) && (!camera.TryGetComponent(out instanceRenderSettings) || instanceRenderSettings.Settings.Supported);
        }
    }
}