using System.Collections.Generic;
using XCEngine;
using XCEngine.Rendering;

namespace XCEngine.Rendering.Universal
{
    public abstract class ScriptableRenderer
    {
        private readonly List<ScriptableRendererFeature> m_features =
            new List<ScriptableRendererFeature>();
        private readonly List<ScriptableRenderPass> m_activePassQueue =
            new List<ScriptableRenderPass>();

        protected ScriptableRenderer()
        {
        }

        public void EnqueuePass(
            ScriptableRenderPass renderPass)
        {
            if (renderPass == null)
            {
                return;
            }

            int insertIndex = m_activePassQueue.Count;
            while (insertIndex > 0 &&
                   m_activePassQueue[insertIndex - 1].renderPassEvent >
                       renderPass.renderPassEvent)
            {
                insertIndex--;
            }

            m_activePassQueue.Insert(
                insertIndex,
                renderPass);
        }

        protected void AddFeature(
            ScriptableRendererFeature feature)
        {
            if (feature == null)
            {
                return;
            }

            m_features.Add(feature);
            feature.Create();
        }

        protected virtual void AddRenderPasses(
            RenderingData renderingData)
        {
        }

        internal bool SupportsStageRenderGraph(
            CameraFrameStage stage)
        {
            RenderingData renderingData = new RenderingData(stage);
            BuildPassQueue(renderingData);
            for (int i = 0; i < m_activePassQueue.Count; ++i)
            {
                ScriptableRenderPass renderPass = m_activePassQueue[i];
                if (renderPass != null &&
                    renderPass.SupportsStage(stage))
                {
                    return true;
                }
            }

            return false;
        }

        internal bool RecordStageRenderGraph(
            ScriptableRenderContext context)
        {
            if (context == null)
            {
                return false;
            }

            RenderingData renderingData =
                new RenderingData(context);
            BuildPassQueue(renderingData);

            bool recordedAnyPass = false;
            for (int i = 0; i < m_activePassQueue.Count; ++i)
            {
                ScriptableRenderPass renderPass = m_activePassQueue[i];
                if (renderPass == null ||
                    !renderPass.SupportsStage(renderingData.stage))
                {
                    continue;
                }

                if (!renderPass.Record(
                        context,
                        renderingData))
                {
                    return false;
                }

                recordedAnyPass = true;
            }

            return recordedAnyPass;
        }

        private void BuildPassQueue(
            RenderingData renderingData)
        {
            m_activePassQueue.Clear();

            for (int i = 0; i < m_features.Count; ++i)
            {
                ScriptableRendererFeature feature = m_features[i];
                if (feature == null || !feature.isActive)
                {
                    continue;
                }

                feature.AddRenderPasses(
                    this,
                    renderingData);
            }

            AddRenderPasses(renderingData);
        }
    }
}