using UnityEngine;
using UnityEngine.Experimental.Rendering;
using UnityEngine.Rendering;

namespace FidelityFX
{
    internal class CacaoResources
    {
        public RenderTexture LoadCounter;

        public RenderTexture DeinterleavedDepths;
        public RenderTexture DeinterleavedNormals;
        public RenderTexture SsaoBufferPing;
        public RenderTexture SsaoBufferPong;
        public RenderTexture ImportanceMap;
        public RenderTexture ImportanceMapPong;
        public RenderTexture DownsampledSsaoBuffer;
        
        public bool CreateLoadCounter()
        {
            LoadCounter = new RenderTexture(1, 1, 0, GraphicsFormat.R32_UInt) { name = "FFX_CACAO_LOAD_COUNTER", enableRandomWrite = true };
            if (!LoadCounter.Create())
            {
                Debug.LogError("Failed to create load counter resource");
                return false;
            }

            return true;
        }

        public void DestroyLoadCounter()
        {
            DestroyResource(ref LoadCounter);
        }

        public bool CreateResources(in Cacao.BufferSizeInfo bsi)
        {
            CreateArrayResource(out DeinterleavedDepths, "FFX_CACAO_DEINTERLEAVED_DEPTHS", bsi.DeinterleavedDepthBufferWidth, bsi.DeinterleavedDepthBufferHeight, GraphicsFormat.R16_SFloat, 4,4);
            CreateArrayResource(out DeinterleavedNormals, "FFX_CACAO_DEINTERLEAVED_NORMALS", bsi.SsaoBufferWidth, bsi.SsaoBufferHeight, GraphicsFormat.R8G8B8A8_SNorm, 4); // TODO: does SNorm work?
            CreateArrayResource(out SsaoBufferPing, "FFX_CACAO_SSAO_BUFFER_PING", bsi.SsaoBufferWidth, bsi.SsaoBufferHeight, GraphicsFormat.R8G8_UNorm, 4);
            CreateArrayResource(out SsaoBufferPong, "FFX_CACAO_SSAO_BUFFER_PONG", bsi.SsaoBufferWidth, bsi.SsaoBufferHeight, GraphicsFormat.R8G8_UNorm, 4);

            CreateResource(out ImportanceMap, "FFX_CACAO_IMPORTANCE_MAP", bsi.ImportanceMapWidth, bsi.ImportanceMapHeight, GraphicsFormat.R8_UNorm);
            CreateResource(out ImportanceMapPong, "FFX_CACAO_IMPORTANCE_MAP_PONG", bsi.ImportanceMapWidth, bsi.ImportanceMapHeight, GraphicsFormat.R8_UNorm);
            CreateResource(out DownsampledSsaoBuffer, "FFX_CACAO_DOWNSAMPLED_SSAO_BUFFER", bsi.DownsampledSsaoBufferWidth, bsi.DownsampledSsaoBufferHeight, GraphicsFormat.R8_UNorm);
            
            return true;
        }

        public void DestroyResources()
        {
            DestroyResource(ref DownsampledSsaoBuffer);
            DestroyResource(ref ImportanceMapPong);
            DestroyResource(ref ImportanceMap);
            DestroyResource(ref SsaoBufferPong);
            DestroyResource(ref SsaoBufferPing);
            DestroyResource(ref DeinterleavedNormals);
            DestroyResource(ref DeinterleavedDepths);
        }

        private static bool CreateResource(out RenderTexture resource, string name, uint width, uint height, GraphicsFormat format)
        {
            resource = new RenderTexture((int)width, (int)height, 0, format) { name = name, enableRandomWrite = true };
            return resource.Create();
        }
        
        private static bool CreateArrayResource(out RenderTexture resource, string name, uint width, uint height, GraphicsFormat format, int arraySize, int mipCount = 1)
        {
            var desc = new RenderTextureDescriptor
            {
                width = (int)width,
                height = (int)height,
                depthBufferBits = 0,
                msaaSamples = 1,
                graphicsFormat = format,
                useMipMap = mipCount > 1,
                mipCount = mipCount,
                autoGenerateMips = false,
                enableRandomWrite = true,
                dimension = TextureDimension.Tex2DArray,
                volumeDepth = arraySize,
            };
            
            resource = new RenderTexture(desc);
            return resource.Create();
        }
        
        private static void DestroyResource(ref RenderTexture resource)
        {
            if (resource == null)
                return;
            
            resource.Release();
            resource = null;
        }
    }
}