using System;
using XCEngine;
using XCEngine.Rendering;

namespace XCEngine.Rendering.Universal
{
    internal enum UniversalSceneRecordingKind
    {
        BeforeOpaqueInjection,
        OpaqueScene,
        AfterOpaqueInjection,
        BeforeSkyboxInjection,
        SkyboxScene,
        AfterSkyboxInjection,
        BeforeTransparentInjection,
        TransparentScene,
        AfterTransparentInjection
    }

    internal sealed class UniversalSceneRecordingPass : ScriptableRenderPass
    {
        private readonly UniversalSceneRecordingKind m_recordingKind;

        public UniversalSceneRecordingPass(
            RenderPassEvent passEvent,
            UniversalSceneRecordingKind recordingKind)
        {
            renderPassEvent = passEvent;
            m_recordingKind = recordingKind;
        }

        protected override bool RecordRenderGraph(
            ScriptableRenderContext context,
            RenderingData renderingData)
        {
            return context != null &&
                   renderingData != null &&
                   renderingData.isMainSceneStage &&
                   RecordSceneStep(context);
        }

        private bool RecordSceneStep(
            ScriptableRenderContext context)
        {
            switch (m_recordingKind)
            {
                case UniversalSceneRecordingKind.BeforeOpaqueInjection:
                    return RecordBeforeOpaqueInjection(context);
                case UniversalSceneRecordingKind.OpaqueScene:
                    return RecordOpaqueScenePhase(context);
                case UniversalSceneRecordingKind.AfterOpaqueInjection:
                    return RecordAfterOpaqueInjection(context);
                case UniversalSceneRecordingKind.BeforeSkyboxInjection:
                    return RecordBeforeSkyboxInjection(context);
                case UniversalSceneRecordingKind.SkyboxScene:
                    return RecordSkyboxScenePhase(context);
                case UniversalSceneRecordingKind.AfterSkyboxInjection:
                    return RecordAfterSkyboxInjection(context);
                case UniversalSceneRecordingKind.BeforeTransparentInjection:
                    return RecordBeforeTransparentInjection(context);
                case UniversalSceneRecordingKind.TransparentScene:
                    return RecordTransparentScenePhase(context);
                case UniversalSceneRecordingKind.AfterTransparentInjection:
                    return RecordAfterTransparentInjection(context);
                default:
                    return false;
            }
        }
    }

    internal sealed class UniversalSceneFeature : ScriptableRendererFeature
    {
        private readonly UniversalRendererData m_rendererData;
        private readonly UniversalSceneRecordingPass m_beforeOpaquePass =
            new UniversalSceneRecordingPass(
                RenderPassEvent.BeforeRenderingOpaques,
                UniversalSceneRecordingKind.BeforeOpaqueInjection);
        private readonly UniversalSceneRecordingPass m_opaquePass =
            new UniversalSceneRecordingPass(
                RenderPassEvent.RenderOpaques,
                UniversalSceneRecordingKind.OpaqueScene);
        private readonly UniversalSceneRecordingPass m_afterOpaquePass =
            new UniversalSceneRecordingPass(
                RenderPassEvent.AfterRenderingOpaques,
                UniversalSceneRecordingKind.AfterOpaqueInjection);
        private readonly UniversalSceneRecordingPass m_beforeSkyboxPass =
            new UniversalSceneRecordingPass(
                RenderPassEvent.BeforeRenderingSkybox,
                UniversalSceneRecordingKind.BeforeSkyboxInjection);
        private readonly UniversalSceneRecordingPass m_skyboxPass =
            new UniversalSceneRecordingPass(
                RenderPassEvent.RenderSkybox,
                UniversalSceneRecordingKind.SkyboxScene);
        private readonly UniversalSceneRecordingPass m_afterSkyboxPass =
            new UniversalSceneRecordingPass(
                RenderPassEvent.AfterRenderingSkybox,
                UniversalSceneRecordingKind.AfterSkyboxInjection);
        private readonly UniversalSceneRecordingPass m_beforeTransparentPass =
            new UniversalSceneRecordingPass(
                RenderPassEvent.BeforeRenderingTransparents,
                UniversalSceneRecordingKind.BeforeTransparentInjection);
        private readonly UniversalSceneRecordingPass m_transparentPass =
            new UniversalSceneRecordingPass(
                RenderPassEvent.RenderTransparents,
                UniversalSceneRecordingKind.TransparentScene);
        private readonly UniversalSceneRecordingPass m_afterTransparentPass =
            new UniversalSceneRecordingPass(
                RenderPassEvent.AfterRenderingTransparents,
                UniversalSceneRecordingKind.AfterTransparentInjection);

        public UniversalSceneFeature(
            UniversalRendererData rendererData)
        {
            m_rendererData = rendererData;
        }

        public override void AddRenderPasses(
            ScriptableRenderer renderer,
            RenderingData renderingData)
        {
            if (renderer == null ||
                renderingData == null ||
                !renderingData.isMainSceneStage ||
                m_rendererData == null)
            {
                return;
            }

            if (m_rendererData.renderOpaque)
            {
                renderer.EnqueuePass(m_beforeOpaquePass);
                renderer.EnqueuePass(m_opaquePass);
                renderer.EnqueuePass(m_afterOpaquePass);
            }

            if (m_rendererData.renderSkybox)
            {
                renderer.EnqueuePass(m_beforeSkyboxPass);
                renderer.EnqueuePass(m_skyboxPass);
                renderer.EnqueuePass(m_afterSkyboxPass);
            }

            if (m_rendererData.renderTransparent)
            {
                renderer.EnqueuePass(m_beforeTransparentPass);
                renderer.EnqueuePass(m_transparentPass);
                renderer.EnqueuePass(m_afterTransparentPass);
            }
        }
    }

    public sealed class UniversalRenderer : ScriptableRenderer
    {
        public UniversalRenderer(
            UniversalRendererData rendererData)
        {
            UniversalRendererData resolvedData =
                rendererData ?? new UniversalRendererData();
            AddFeature(new UniversalSceneFeature(resolvedData));
        }
    }
}