using System.Runtime.InteropServices;
using FidelityFX;
using UnityEngine.Experimental.Rendering;

namespace UnityEngine.Rendering.PostProcessing
{
    internal abstract class SGSR2Upscaler: Upscaler
    {
        public static bool IsSupported => SystemInfo.supportsComputeShaders;
        
        protected RenderTexture _colorLuma;
        protected RenderTexture _motionDepthAlpha;
        protected RenderTexture _motionDepthClipAlpha;
        protected readonly RenderTexture[] _lumaHistory = new RenderTexture[2];
        protected readonly RenderTexture[] _upscaleHistory = new RenderTexture[2];

        protected readonly ConstantsBuffer<SGSR2.Params> _paramsBuffer = new();

        protected uint _frameCount = 0;
        
        public override void CreateContext(PostProcessRenderContext context, Upscaling config)
        {
            CreateRenderTexture(ref _colorLuma, "ColorLuma", config.MaxRenderSize, GraphicsFormat.R32_UInt, true);
            CreateRenderTexture(ref _motionDepthAlpha, "MotionDepthAlpha", config.MaxRenderSize, GraphicsFormat.R16G16B16A16_SFloat, true);
            CreateRenderTexture(ref _motionDepthClipAlpha, "MotionDepthClipAlpha", config.MaxRenderSize, GraphicsFormat.R16G16B16A16_SFloat, true);
            CreateRenderTextureArray(_lumaHistory, "LumaHistory", config.MaxRenderSize, GraphicsFormat.R32_UInt, true);
            CreateRenderTextureArray(_upscaleHistory, "History", config.UpscaleSize, context.sourceFormat, true);
            
            _paramsBuffer.Init();
        }

        public override void DestroyContext()
        {
            base.DestroyContext();
            
            _paramsBuffer.Destroy();
            
            DestroyRenderTextureArray(_upscaleHistory);
            DestroyRenderTextureArray(_lumaHistory);
            DestroyRenderTexture(ref _motionDepthClipAlpha);
            DestroyRenderTexture(ref _motionDepthAlpha);
            DestroyRenderTexture(ref _colorLuma);
        }
    }
}