using System;
using System.Runtime.CompilerServices;
using XCEngine;
using XCEngine.Rendering;

namespace XCEngine.Rendering.Universal
{
    public abstract class ScriptableRendererData
        : ScriptableObject
    {
        public ScriptableRendererFeature[] rendererFeatures;
        private readonly ScriptableRendererFeatureCollection
            m_featureCollection;
        private ScriptableRenderer m_rendererInstance;
        private bool m_rendererInvalidated;
        private int m_runtimeStateVersion = 1;
        private int m_rendererFeatureCollectionHash;
        private bool m_rendererFeatureCollectionHashResolved;

        protected ScriptableRendererData()
        {
            rendererFeatures =
                Array.Empty<ScriptableRendererFeature>();
            m_featureCollection =
                new ScriptableRendererFeatureCollection(this);
        }

        internal ScriptableRenderer CreateRendererInstance()
        {
            return GetRendererInstance();
        }

        internal ScriptableRenderer GetRendererInstance()
        {
            if (m_rendererInstance == null)
            {
                m_rendererInstance = CreateRenderer();
                if (m_rendererInstance != null)
                {
                    SetupRendererInstance(m_rendererInstance);
                    m_rendererInvalidated = false;
                }
            }

            return m_rendererInstance;
        }

        internal void SetupRendererInstance(
            ScriptableRenderer renderer)
        {
            if (renderer == null)
            {
                return;
            }

            SetupRenderer(renderer);
        }

        internal void SetDirtyInstance()
        {
            SetDirty();
        }

        internal void InvalidateRendererFeaturesInstance()
        {
            m_featureCollection.Invalidate(
                ref rendererFeatures,
                ref m_rendererFeatureCollectionHash,
                ref m_rendererFeatureCollectionHashResolved);
            SetDirty();
        }

        internal int GetRuntimeStateVersionInstance()
        {
            SynchronizeRendererFeatureCollectionState();
            return m_runtimeStateVersion;
        }

        internal void ReleaseRuntimeResourcesInstance()
        {
            ReleaseRendererSetupCache();
            ReleaseRuntimeResources();
            m_rendererInvalidated = false;
        }

        internal void ConfigureCameraRenderRequestInstance(
            CameraRenderRequestContext context)
        {
            ConfigureCameraRenderRequest(context);
            m_featureCollection.ConfigureCameraRenderRequest(
                ref rendererFeatures,
                context);
        }

        internal void ConfigureCameraFramePlanInstance(
            ScriptableRenderPipelinePlanningContext context)
        {
            ConfigureCameraFramePlan(context);

            ScriptableRenderer renderer =
                GetRendererInstance();
            if (renderer != null)
            {
                renderer.ConfigureCameraFramePlanInstance(
                    context);
            }

            m_featureCollection.ConfigureCameraFramePlan(
                ref rendererFeatures,
                context);

            if (renderer != null)
            {
                renderer.FinalizeCameraFramePlanInstance(
                    context);
            }
        }

        internal bool ConfigureRenderSceneSetupInstance(
            RenderSceneSetupContext context)
        {
            ConfigureRenderSceneSetup(context);

            ScriptableRenderer renderer =
                GetRendererInstance();
            if (renderer != null)
            {
                renderer.ConfigureRenderSceneSetupInstance(
                    context);
            }

            m_featureCollection.ConfigureRenderSceneSetup(
                ref rendererFeatures,
                context);

            return context != null &&
                   context.isConfigured;
        }

        internal bool ConfigureDirectionalShadowExecutionStateInstance(
            DirectionalShadowExecutionContext context)
        {
            ConfigureDirectionalShadowExecutionState(
                context);

            ScriptableRenderer renderer =
                GetRendererInstance();
            if (renderer != null)
            {
                renderer
                    .ConfigureDirectionalShadowExecutionStateInstance(
                        context);
            }

            m_featureCollection
                .ConfigureDirectionalShadowExecutionState(
                    ref rendererFeatures,
                    context);

            return context != null &&
                   context.isConfigured;
        }

        protected virtual ScriptableRenderer CreateRenderer()
        {
            return null;
        }

        protected virtual void SetupRenderer(
            ScriptableRenderer renderer)
        {
            AddRendererFeatures(
                renderer,
                GetRendererFeatures());
        }

        protected virtual void ConfigureCameraRenderRequest(
            CameraRenderRequestContext context)
        {
        }

        protected virtual void ConfigureCameraFramePlan(
            ScriptableRenderPipelinePlanningContext context)
        {
        }

        protected virtual void ConfigureRenderSceneSetup(
            RenderSceneSetupContext context)
        {
        }

        protected virtual void ConfigureDirectionalShadowExecutionState(
            DirectionalShadowExecutionContext context)
        {
        }

        protected virtual void ReleaseRuntimeResources()
        {
        }

        protected virtual ScriptableRendererFeature[]
        CreateDefaultRendererFeatures()
        {
            return Array.Empty<ScriptableRendererFeature>();
        }

        protected bool isInvalidated
        {
            get
            {
                return m_rendererInvalidated;
            }
        }

        protected bool HasDirectionalShadow(
            CameraRenderRequestContext context)
        {
            return context != null &&
                   InternalCalls
                       .Rendering_CameraRenderRequestContext_GetHasDirectionalShadow(
                           context.nativeHandle);
        }

        protected void ClearDirectionalShadow(
            CameraRenderRequestContext context)
        {
            if (context == null)
            {
                return;
            }

            InternalCalls
                .Rendering_CameraRenderRequestContext_ClearDirectionalShadow(
                    context.nativeHandle);
        }

        protected void SetDirty()
        {
            ReleaseRendererSetupCache();
            m_rendererInvalidated = true;
            unchecked
            {
                ++m_runtimeStateVersion;
            }

            if (m_runtimeStateVersion <= 0)
            {
                m_runtimeStateVersion = 1;
            }
        }

        protected void AddRendererFeature(
            ScriptableRenderer renderer,
            ScriptableRendererFeature rendererFeature)
        {
            if (renderer == null ||
                rendererFeature == null)
            {
                return;
            }

            renderer.AddFeatureInstance(rendererFeature);
        }

        protected void AddRendererFeatures(
            ScriptableRenderer renderer,
            ScriptableRendererFeature[] rendererFeatures)
        {
            if (renderer == null ||
                rendererFeatures == null)
            {
                return;
            }

            for (int i = 0; i < rendererFeatures.Length; ++i)
            {
                AddRendererFeature(
                    renderer,
                    rendererFeatures[i]);
            }
        }

        protected void ResetRendererFeaturesToDefault()
        {
            m_featureCollection.Reset(
                ref rendererFeatures,
                CreateDefaultRendererFeatures() ??
                Array.Empty<ScriptableRendererFeature>());
        }

        private ScriptableRendererFeature[] GetRendererFeatures()
        {
            return m_featureCollection.GetFeatures(
                ref rendererFeatures);
        }

        private void SynchronizeRendererFeatureCollectionState()
        {
            m_featureCollection.Synchronize(
                ref rendererFeatures,
                ref m_rendererFeatureCollectionHash,
                ref m_rendererFeatureCollectionHashResolved,
                SetDirty);
        }

        private void ReleaseRendererSetupCache()
        {
            if (m_rendererInstance != null)
            {
                m_rendererInstance.ReleaseRuntimeResourcesInstance();
                m_rendererInstance = null;
                m_featureCollection.ResetResolvedCache();
                return;
            }

            m_featureCollection.ReleaseRuntimeResources();
        }
    }
}