using StgSharp.Geometries;
using StgSharp.Graphics;
using StgSharp.Graphics.GL;
using StgSharp.Logic;
using StgSharp.Math;

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Channels;
using System.Threading.Tasks;

namespace StgSharp
{
    public class ParticleStream : glRenderStream
    {
        public ParticleStream(ViewPort args, (int,int,int) cube) : base(args, (100,100,100))
        {
        }

        protected override string[] InputPortsName => ["input_1"];

        protected override string[] OutputPortsName => ["output_1"];

        protected override void Deinit()
        {
            throw new NotImplementedException();
        }

        ShaderProgram s;
        PlainInstancingBuffer<ParticleOnPlain> buffer;
        VertexBuffer vbo;
        VertexArray vao;
        ElementBuffer ebo;

        FrameBuffer fbo;
        
        

        internal static vec3d DefaultRotation(TimeSpanProvider provider, out float rotation)
        {
            rotation = 0.1f;
            float angle = provider.CurrentSpan * 0.1f;
            return new vec3d(
                0.01f * Scaler.Cos(angle),
                - 0.01f * Scaler.Sin(angle),
                0
                );
        }

        protected override void Init()
        {
            buffer = new PlainInstancingBuffer<ParticleOnPlain>();
            for (int i = 0; i < 10; i++)
            {
                float ai  =Scaler.Abs(i - 5.0f);
                for (int t = 0; t < 10; t++)
                {
                    float at = Scaler.Abs(t - 5.0f);

                    ParticleOnPlain p = new ParticleOnPlain(buffer);
                    ((IInstancing)p).Coord = new vec3d(
                        (-5 + i) * 0.2f + 0.1f, (-5 + t) * 0.2f + 0.1f, 0);
                    ((IInstancing)p).Scale = 
                        Scaler.MinOf(i, t) * 0.15f;
                    ((IInstancing)p).Motion = new GeometryMotion(
                        true, this.timeProvider,
                        DefaultRotation)
                        ;
                }
            }

            SetSizeLimit(800, 800, 800, 800);

            FrameSizeCallback =
                (IntPtr id, uint width, uint height) => glFunc.Viewport(0, 0, width, height);

            s = CreateShaderProgram();
            Shader pvs = CreateShaderSegment(ShaderType.Vertex ,1);
            Shader pfs = CreateShaderSegment(ShaderType.Fragment ,1);

            pvs.Compile(0, Shader.FromCodeFile("Shader\\particle.vert"));
            pvs.AttachTo(0,s);
            pfs.Compile(0, Shader.FromCodeFile("Shader\\particle.frag"));
            pfs.AttachTo(0,s);
            s.Link();

            vbo = CreateVertexBuffer(3);
            vao = CreateVertexArray(1);
            ebo = CreateElementBuffer(1);
            vbo.Bind(0);

            Rectangle rec = new Rectangle
                (
                0.05f,0.05f,
                0.05f,-0.05f,
                -0.05f,-0.05f,
                -0.05f,0.05f
                );
            
            vao.Bind(0);
            vbo.WriteVectorData(0, rec.VertexStream, BufferUsage.StaticDraw);
            ebo.SetValue(0, rec.VertexIndices, BufferUsage.StaticDraw);
            VertexArray.SetVertexAttribute(0, 3, TypeCode.Single, false, 4 * sizeof(float),0);
            
            vbo.WriteVectorData<vec4d>(1, buffer.CoordAndRotationSpan,BufferUsage.StreamDraw);
            VertexArray.SetVertexAttribute(1, 3, TypeCode.Single, false, 4 * sizeof(float), 0);
            VertexArray.SetVertexAttribute(2, 1, TypeCode.Single, false, 4 * sizeof(float), 3 * sizeof(float));

            glFunc.VertexAttributeDivisor(1, 1);
            glFunc.VertexAttributeDivisor(2, 1);

            vbo.WriteScalerData<float>(2, buffer.ScalingSpan, BufferUsage.StaticDraw);
            VertexArray.SetVertexAttribute(3,1,TypeCode.Single,false,sizeof(float),0);
            
            glFunc.VertexAttributeDivisor(3, 1);

            

            vbo.Unbind();
            VertexArray.BindNull();

            NativeCameraViewTarget
                (
                (0,0,-100),
                (0,0,0),
                (0,1,0)
                );
            NativeCameraViewRange(new Degree(1.5f),Vec2d.Zero,(50,50));
            NativeCameraUniform(s,"Camera");

            s.Use();
            fbo = CreateFrameBuffer(1);
            rbo = CreateRenderBuffer(1);

            fbo.Bind(0);
            rbo.Bind(0);
            glFunc.SetRenderBufferStorage(
                RenderBufferInternalFormat.Depth24_Stencil8, this.Size);


            t = CreateTexture(1);
            t.Bind2D(0);
            glFunc.TextureImage2d(Texture2DTarget.Texture2D, 0, (int)ImageChannel.WithAlphaChannel,
                (uint)Width, (uint)Height, (int)ImageChannel.WithAlphaChannel, ImageChannelLayout.Byte, glHandle.ZeroHandle);

            t.Set2dWrapProperty(Wrap.Repeat, Wrap.Repeat);
            t.Set2dFilterProperty(Filter.Nearest, Filter.Nearest);
             

            glFunc.FrameBufferTexture2d(FrameBufferTarget.All, glAttachment.Color(0),
        Texture2DTarget.Texture2D,t[0],0);

            glFunc.CombineFrameBufferRenderBuffer(fbo[0], rbo[0]);

            int streamLength = this.Width * this.Height * 4;
            byte[] imageStream = new byte[streamLength];
            i = Image.FromMemory(this.Size,4,imageStream);
        }

        TextureGL t;
        RenderBuffer rbo;
        Image i;

        protected override void Main(
            in Dictionary<string, BlueprintPipeline> input, 
            in Dictionary<string, BlueprintPipeline> output)
        {
            buffer.UpdateAllParticles();

            fbo.Bind(0);
            vao.Bind(0);


            glFunc.ClearColor(0.6f,0.1f,0.3f,1);
            glFunc.Clear(MaskBufferBit.COLOR | MaskBufferBit.DEPTH);

            vbo.Bind(1);
            vbo.WriteVectorData<vec4d>(1, buffer.CoordAndRotationSpan, BufferUsage.StreamDraw);
            
            s.Use();

            NativeCamera.SetAllUniforms();

            glFunc.DrawElementsInstanced(
                GeometryType.TRIANGLES, 6, TypeCode.UInt32,IntPtr.Zero,100
                );
            glFunc.WaitAccomplishment();
            VertexArray.BindNull();

            /**/

            t.Bind2D(0);

            glFunc.GetTextureImage(Texture2DTarget.Texture2D, 0,ImageChannel.WithAlphaChannel,
                ImageChannelLayout.Byte,ref i.data);

            //Array.Fill<byte>(i.DataStream, 24);
            output["output_1"].CompleteAndWriteData( new TexturePipeline(i));
            FrameBuffer.BindNull();
            /**/

            /*
            //BlueprintPipeline.SkipAll(output);
            SwapBuffers();
            PollEvents();
            /**/
        }

        protected override void ProcessInput()
        {
            if (CheckKey(KeyboardKey.ESCAPE) == KeyStatus.PRESS)
            {
                InternalIO.glfwSetWindowShouldClose(CanvasHandle, 1);
            }
        }
    }
}