using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Net.Http.Headers;
using System.Numerics;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Security.Cryptography;
using System.Text;

namespace Veldrid.Common.Plot
{
    public class LineSeries: BaseVeldridRender,IZoomRender
    {
        public Vector2 WindowScale { get; set; } = Vector2.One;
        public float HScale { get; set; } = 1;
        public float VScale { get; set; } = 1;
        public float HOffset { get; set; }
        public float VOffset { get; set; }
        public bool ZoomEnbled { get; set; }
        private const uint ThreadGroupSizeX = 1000;
        private ProjView projView;
        Pipeline pipeline;
        private PlotInfo plotInfo;
        DeviceBuffer plotInfoBuffer;
        DeviceBuffer projViewBuffer;
        DeviceBuffer dataBuffer;
        ResourceLayout dataLayout;
        ResourceSet dataSet;
        ResourceLayout infoLayout;
        ResourceSet infoSet;
        Shader[] shaders;


        DeviceBuffer resultBuffer;
        DeviceBuffer cpuBuffer;
        ResourceLayout computeLayout;
        ResourceSet computeSet;
        Pipeline computePipline;
        ResourceLayout computeLineInfoLayout;
        ResourceSet computeLineInfoSet;
        Shader computeShader;
        CommandList computeCommandList;
        private object locker = new object();
        public LineSeries(VeldridContent content, uint datalen=1000,uint plotcount=4):base(content)
        {
            dataLenght = datalen;
            PlotInfos = new SeriesInfo[plotcount];
            Margin = new Padding(40, 10, 10, 20);
        }
        internal override void DisposeResources()
        {
            base.DisposeResources();
            pipeline?.Dispose();
            plotInfoBuffer?.Dispose();
            projViewBuffer?.Dispose();
            dataBuffer?.Dispose();
            dataLayout?.Dispose();
            dataSet?.Dispose();
            infoLayout?.Dispose();
            infoSet?.Dispose();


            resultBuffer?.Dispose();
            cpuBuffer?.Dispose();
            computeLayout?.Dispose();
            computeSet?.Dispose();
            computePipline?.Dispose();
            computeCommandList?.Dispose();
            computeLineInfoLayout?.Dispose();
            computeLineInfoSet?.Dispose();
            computeShader?.Dispose();
        }
        private void CreateDataBuffer()
        {
            if (DataLenght == 0  || PlotInfos  ==null|| PlotInfos.Length == 0) return;
            lock (locker)
            {
                dataBuffer?.Dispose();
                pipeline?.Dispose();
                dataBuffer = ResourceFactory.CreateBuffer(new BufferDescription()
                {
                    SizeInBytes = (uint)(DataLenght * PlotInfos.Length * 4),
                    Usage = BufferUsage.StructuredBufferReadWrite,
                    StructureByteStride = 4,
                });
                dataSet = ResourceFactory.CreateResourceSet(new ResourceSetDescription(dataLayout, dataBuffer));
                pipeline = CreatePipLine(PrimitiveTopology.LineStrip, new ResourceLayout[] { dataLayout, infoLayout }, new VertexLayoutDescription[0],new[] { shaders[0], shaders[1] });
                datastartindex = 0;
                datatotallen = 0;
                TotalCount = 0;
                MaxAndMin = new Vector2[PlotInfos.Length];
                CreateComputeBuffer();
            }
        }

        internal override void CreateResources()
        {
            base.CreateResources();
            
            plotInfoBuffer = ResourceFactory.CreateBuffer(new BufferDescription()
            {
                SizeInBytes = (uint)Unsafe.SizeOf<PlotInfo>(),
                Usage = BufferUsage.UniformBuffer,
            });
            projViewBuffer = ResourceFactory.CreateBuffer(new BufferDescription()
            {
                SizeInBytes = (uint)Unsafe.SizeOf<ProjView>(),
                Usage = BufferUsage.UniformBuffer ,
            });
            datatotallen = 0;
            datastartindex = 0;
            shaders = CreateShader("LineSeries");
            dataLayout = ResourceFactory.CreateResourceLayout(new ResourceLayoutDescription(new ResourceLayoutElementDescription()
            {
                Name = "DataBuffer",
                Stages = ShaderStages.Vertex,
                Kind = ResourceKind.StructuredBufferReadOnly,
            }));
            infoLayout = ResourceFactory.CreateResourceLayout(new ResourceLayoutDescription(
                new ResourceLayoutElementDescription()
                {
                    Name = "InfoBuffer",
                    Kind = ResourceKind.UniformBuffer,
                    Stages = ShaderStages.Vertex,
                },
                new ResourceLayoutElementDescription()
                {
                    Name = "ProjView",
                    Kind = ResourceKind.UniformBuffer,
                    Stages = ShaderStages.Vertex,
                }));
            infoSet = ResourceFactory.CreateResourceSet(new ResourceSetDescription(infoLayout, plotInfoBuffer, projViewBuffer));

            resultBuffer = ResourceFactory.CreateBuffer(new BufferDescription(20 * 4, BufferUsage.StructuredBufferReadWrite, 4));
            cpuBuffer = ResourceFactory.CreateBuffer(new BufferDescription(resultBuffer.SizeInBytes, BufferUsage.Staging));
            computeLayout = ResourceFactory.CreateResourceLayout(new ResourceLayoutDescription(
                new ResourceLayoutElementDescription("DataBuffer", ResourceKind.StructuredBufferReadOnly, ShaderStages.Compute),
                new ResourceLayoutElementDescription("ResultDataBuffer", ResourceKind.StructuredBufferReadWrite, ShaderStages.Compute)));
            computeLineInfoLayout = ResourceFactory.CreateResourceLayout(new ResourceLayoutDescription(
                new ResourceLayoutElementDescription("InfoBuffer", ResourceKind.UniformBuffer, ShaderStages.Compute)));
            computeLineInfoSet = ResourceFactory.CreateResourceSet(new ResourceSetDescription(computeLineInfoLayout, plotInfoBuffer));
            ShaderDescription shaderDescription = new ShaderDescription(ShaderStages.Compute, GLSLManger.LoadShader("LineSeries.hlsl"), "main")
            {
                Debug = true,
            };
            computeShader = ResourceFactory.CreateShader(shaderDescription);
            computeCommandList = ResourceFactory.CreateCommandList() ;
            CreateDataBuffer();
        }

        private void CreateComputeBuffer()
        {
            computeSet?.Dispose();
            computePipline?.Dispose();
            computeSet = ResourceFactory.CreateResourceSet(new ResourceSetDescription(computeLayout, dataBuffer, resultBuffer));
            computePipline = ResourceFactory.CreateComputePipeline(new ComputePipelineDescription(computeShader, new[] { computeLayout, computeLineInfoLayout }, ThreadGroupSizeX, 1, 1));
        }
        struct PlotInfo
        {
            public RgbaFloat Color;
            public uint PlotIndex;
            public float Interval;
            public uint DataStartIndex;
            public uint PlotDataLenght;
        }
        struct ProjView
        {
            public Matrix4x4 Proj;
            public Matrix4x4 View;
        }
        public void Clear()
        {
            datastartindex = 0;
            datatotallen = 0;
            TotalCount = 0;
        }
        public ulong TotalCount { get; private set; }
        public Vector2[] MaxAndMin { get; private set; } = new Vector2[0];
        public unsafe void AddData(float[] data)
        {
            if (DataLenght == 0 || PlotInfos == null || PlotInfos.Length == 0) return;
            if (data == null|| data.Length!=PlotInfos.Length) return;
            TotalCount++;
            for(int i=0;i<data.Length;i++)
            {
                GraphicsDevice.UpdateBuffer(dataBuffer,(uint)((datastartindex+i*DataLenght)*Unsafe.SizeOf<float>()),ref data[i],(uint)Unsafe.SizeOf<float>());

            }
            datastartindex++;
            datatotallen++;
            if(datatotallen>DataLenght)datatotallen = DataLenght;
            if (datastartindex >= DataLenght) datastartindex = 0;
            MaxAndMin = new Vector2[PlotInfos.Length];
            //return;
            if (datatotallen > 0)
            {
                computeCommandList.Begin();
                CalcMaxMin(computeCommandList);                
                computeCommandList.End();
                GraphicsDevice.SubmitCommands(computeCommandList);
                GraphicsDevice.WaitForIdle();
            }
        }
        private unsafe void CalcMaxMin(CommandList command)
        {
            MaxAndMin = new Vector2[PlotInfos.Length];
            plotInfo.DataStartIndex = datatotallen;
            plotInfo.PlotDataLenght = DataLenght;
            command.SetPipeline(computePipline);
            command.SetComputeResourceSet(0, computeSet);
            command.SetComputeResourceSet(1, computeLineInfoSet);
            for (uint i = 0; i < PlotInfos.Length; i++)
            {
                plotInfo.PlotIndex = i;
                command.UpdateBuffer(plotInfoBuffer, 0, plotInfo);
                command.Dispatch((uint)MathF.Ceiling(((float)datatotallen) / ThreadGroupSizeX), 1, 1);
            }
            command.CopyBuffer(resultBuffer, 0, cpuBuffer, 0, (uint)(MaxAndMin.Length * Unsafe.SizeOf<Vector2>()));
            var mapped = GraphicsDevice.Map(cpuBuffer, MapMode.ReadWrite);
            Unsafe.CopyBlock(ref Unsafe.As<Vector2, byte>(ref MaxAndMin[0]), ref Unsafe.AsRef<byte>(mapped.Data.ToPointer()), (uint)(MaxAndMin.Length * Unsafe.SizeOf<Vector2>()));
            GraphicsDevice.Unmap(cpuBuffer);
        }
        internal unsafe override void DrawData()
        {
            if (DataLenght == 0 || PlotInfos == null || PlotInfos.Length == 0) return;
            lock (locker)
            {
                base.DrawData();
                if (datatotallen == 0) return;
                //CalcMaxMin(CommandList);
                projView.Proj = OrthographicMatrix;
                projView.View = GetLineMatrix(HScale,VScale,0,VOffset);
                CommandList.SetFramebuffer(MainSwapchainBuffer);
                CommandList.UpdateBuffer(projViewBuffer, 0, projView);
                CommandList.UpdateBuffer(plotInfoBuffer, 0, plotInfo);
                CommandList.SetPipeline(pipeline);
                CommandList.SetGraphicsResourceSet(0, dataSet);
                CommandList.SetGraphicsResourceSet(1, infoSet);
                for (uint i = 0; i < PlotInfos.Length; i++)
                {
                    if (!PlotInfos[i].Visibily) continue;

                    plotInfo.Color = PlotInfos[i].Color;
                    plotInfo.PlotDataLenght = DataLenght;
                    plotInfo.DataStartIndex = datatotallen == DataLenght ? datastartindex : 0;
                    plotInfo.PlotIndex = i;
                    CommandList.UpdateBuffer(plotInfoBuffer, 0, plotInfo);
                    CommandList.Draw(datatotallen);
                }
            }
        }
        private uint datastartindex = 0;
        private uint datatotallen = 0;
        private uint dataLenght = 1000;

        public float Interval { get => plotInfo.Interval; set => plotInfo.Interval = value; }
        public uint DataLenght 
        { 
            get => dataLenght;
            set
            {
                if (dataLenght != value)
                {
                    dataLenght = value;
                    CreateDataBuffer();
                }
            }
        }

        public SeriesInfo[] PlotInfos = new SeriesInfo[0];


    }
    public class SeriesInfo
    {
        public RgbaFloat Color;
        public bool Visibily;
        public string Name = string.Empty;
    }
}