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

namespace SLSFramework.Rendering.PostProcessing
{
    public class ScriptablePostProcessorFeature : ScriptableRendererFeature
    {
        private List<ScriptablePostProcessorVolume> postProcessorVolumes;
        
        private ScriptablePostProcessorPass afterTransparentPass;
        private ScriptablePostProcessorPass beforePostProcessPass;
        private ScriptablePostProcessorPass afterPostProcessPass;

        public override void Create()
        {
            var stack = VolumeManager.instance.stack;

            postProcessorVolumes = VolumeManager.instance.baseComponentTypeArray
               .Where(t => t.IsSubclassOf(typeof(ScriptablePostProcessorVolume)))
               .Select(t => stack.GetComponent(t) as ScriptablePostProcessorVolume)
               .ToList();

            var afterTransparentPostProcessors = postProcessorVolumes
                .Where(c => c.InjectionPoint == CustomPostProcessInjectionPoint.AfterTransparent)
                .OrderBy(c => c.OrderInInjectionPoint)
                .ToList();
            afterTransparentPass =
                new ScriptablePostProcessorPass("Custom PostProcessor - after Transparent", afterTransparentPostProcessors)
                    {
                        renderPassEvent = RenderPassEvent.AfterRenderingTransparents
                    };

            var beforePostProcessPostProcessors = postProcessorVolumes
                .Where(c => c.InjectionPoint == CustomPostProcessInjectionPoint.BeforePostProcess)
                .OrderBy(c => c.OrderInInjectionPoint)
                .ToList();
            beforePostProcessPass =
                new ScriptablePostProcessorPass("Custom PostProcessor - before PostProcessing", beforePostProcessPostProcessors)
                    {
                        renderPassEvent = RenderPassEvent.BeforeRenderingPostProcessing
                    };

            var afterPostProcessPostProcessors = postProcessorVolumes
                .Where(c => c.InjectionPoint == CustomPostProcessInjectionPoint.AfterPostProcess)
                .OrderBy(c => c.OrderInInjectionPoint)
                .ToList();
            afterPostProcessPass =
                new ScriptablePostProcessorPass("Custom PostProcessor - after PostProcessing", afterPostProcessPostProcessors)
                    {
                        renderPassEvent = RenderPassEvent.AfterRenderingPostProcessing
                    };
        }
        
        public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData)
        {
            // 只有在相机开启后处理时才执行
            if (renderingData.cameraData.postProcessEnabled)
            {
                // 关键点：将 renderingData 传递给 Pass 的 Setup 方法
                // 这样我们就能把数据缓存下来给 RenderGraph 使用了
                if (afterTransparentPass.Setup(ref renderingData))
                {
                    afterTransparentPass.ConfigureInput(ScriptableRenderPassInput.Color);
                    renderer.EnqueuePass(afterTransparentPass);
                }

                if (beforePostProcessPass.Setup(ref renderingData))
                {
                    beforePostProcessPass.ConfigureInput(ScriptableRenderPassInput.Color);
                    renderer.EnqueuePass(beforePostProcessPass);
                }

                if (afterPostProcessPass.Setup(ref renderingData))
                {
                    afterPostProcessPass.ConfigureInput(ScriptableRenderPassInput.Color);
                    renderer.EnqueuePass(afterPostProcessPass);
                }
            }
        }

        protected override void Dispose(bool disposing)
        {
            base.Dispose(disposing);
            if (disposing)
            {
                if (postProcessorVolumes != null)
                {
                    foreach (var item in postProcessorVolumes)
                    {
                        item.Dispose();
                    }
                }
                
                afterTransparentPass = null;
                beforePostProcessPass = null;
                afterPostProcessPass = null;
            }
        }
    }
}