using System;
using System.Runtime.InteropServices;
using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;
namespace X.Rendering.Feature
{
    public enum EFrameGeneration
    {
        AFME,// Adaptive Frame Motion Extrapolation GL_QCOM_frame_extrapolation
        HW_INTERPOLATE,// 华为 Graphics Accelerate Kit 内插值
        HW_EXTRAPOLATION,// 华为 Graphics Accelerate Kit 外插值
        //VGS,// vivo
        FSR2,
        FSR3,
    }

    public unsafe class FG 
    {
        static int frameIndex = 0;
        static RTHandle[] historys = new RTHandle[2];
        static RTHandle presentRt;
        static bool presented = false;
        public static bool UseFG = true;
        
        public static bool CanDoFG => frameIndex > 0 && frameIndex % 3 == 0 && !presented && UseFG;

        [StructLayout(LayoutKind.Sequential)]
        struct AFMEParam
        {
            public IntPtr src;
            public IntPtr data;
            public IntPtr dst;
        }
        static IntPtr data = Marshal.AllocHGlobal(sizeof(AFMEParam));

        public static bool FrameGenearte(ScriptableRenderContext context, CommandBuffer cmd, out RTHandle dst)
        {
#if UNITY_ANDROID && !UNITY_EDITOR
            Debug.Log("FrameGenearte" + frameIndex);
            dst = presentRt;
            var history1 = historys[frameIndex % 2];
            var history2 = historys[frameIndex % 2 == 1 ? 0 : 1];
            AFMEParam* p = (AFMEParam*)data.ToPointer();
            p->src = history1.rt.GetNativeTexturePtr();
            p->data = history2.rt.GetNativeTexturePtr();
            p->dst = dst.rt.GetNativeTexturePtr();
            cmd.IssuePluginEventAndData(RenderingPlugin.GetRenderEventAndDataFunc(), (int)RenderingPlugin.NativeRenderingEvent.DoFGExtrapolation, data);
            context.ExecuteCommandBuffer(cmd);
            cmd.Clear();
            presented = true;
            return true;
#else
            dst = null;
            return false;
#endif
        }

        public static void  RecordFrame(RTHandle source, CommandBuffer cmd)
        {
            presented = false;
            var index = frameIndex++ % 2;
            var desc = source.rt.descriptor;
            desc.graphicsFormat = UnityEngine.Experimental.Rendering.GraphicsFormat.R8G8B8A8_UNorm;
            desc.depthBufferBits = 0;
            RenderingUtils.ReAllocateIfNeeded(ref historys[0], desc);

            RenderingUtils.ReAllocateIfNeeded(ref historys[1], desc);

            RenderingUtils.ReAllocateIfNeeded(ref presentRt, desc);
            var history = historys[index];
            cmd.Blit(source, history);
        }
    }
}