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

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

namespace StgSharp
{
    public class fboFrame : glRenderStream
    {
        public fboFrame(RenderStreamConstructArgs args):base(args)
        {
            
        }

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

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

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

        ShaderProgram s;
        TextureGL t;
        VertexBuffer vbo;
        VertexArray vao;
        ElementBuffer ebo;

        internal TimeSpanProvider spanProvider;

        protected override void Init()
        {
            //spanProvider = new TimeSpanProvider(1 / 60.00f, TimeSpanProvider.DefaultProvider);

            SetSizeLimit(800,800,800,800);

            FrameSizeCallback = new FrameBufferSizeHandler(
                (window, width,height) => {
                    glFunc.Viewport(0, 0, width, height);
            });

            vbo = CreateVertexBuffer(2);
            vao = CreateVertexArray(1);
            ebo = CreateElementBuffer(1);

            Rectangle rec = new Rectangle(
                -0.9f,  0.9f, 0,
                0.9f, 0.9f, 0,
                0.9f, -0.9f, 0,
                -0.9f, -0.9f, 0
                );

            /*
            Rectangle tex = new Rectangle(
                -0.8f, 0.8f, 0,
                0.8f, 0.8f, 0,
                0.8f,  -0.8f, 0,
                -0.8f, -0.8f, 0
                );

            /**/
            /**/
            Rectangle tex = new Rectangle(
                0f, 1f, 0,
                1f, 1f, 0,
                1f, 0f, 0,
                0f, 0f, 0
                );

            /**/

            s = CreateShaderProgram();
            Shader vert = CreateShaderSegment(ShaderType.Vertex, 1);
            Shader frag = CreateShaderSegment(ShaderType.Fragment,1);

            vert.Compile(0, Shader.FromCodeFile("Shader\\fbo.vert"));
            frag.Compile(0, Shader.FromCodeFile("Shader\\fbo.frag"));

            vert.AttachTo(0,s);
            frag.AttachTo(0,s);

            s.Link();

            vao.Bind(0);

            ebo.Bind(0);
            ebo.SetValue(0,rec.VertexIndices,BufferUsage.StaticDraw);

            vbo.Bind(0);
            vbo.WriteVectorData(0,rec.VertexStream, BufferUsage.StaticDraw);
            VertexArray.SetVertexAttribute(0,3,TypeCode.Single,false,4*sizeof(float),0);

            vbo.Bind(1);
            vbo.WriteVectorData(1, tex.VertexStream, BufferUsage.StaticDraw);
            VertexArray.SetVertexAttribute(1, 3, TypeCode.Single, false,4*sizeof(float),0);


            t = CreateTexture(1);
            t.Bind2D(0);
            t.Set2dWrapProperty(Wrap.Repeat, Wrap.Repeat);
            t.Set2dFilterProperty(Filter.Nearest, Filter.Nearest);

            TextureGL.Activate(TextureUnit.Unit0);
            
            texUniform = s.GetUniform<int>("tex");
            glFunc.SetUniformValue(texUniform, 0);

        }

        Uniform<int> texUniform;

        protected override void Main(
            in Dictionary<string, BlueprintPipeline> input, 
            in Dictionary<string, BlueprintPipeline> output)
        {
            TexturePipeline p = input["TextureInput"].Args as TexturePipeline;
            Image i = (p??throw  new Exception("Pipeline has null value")).Value;

            FrameBuffer.BindNull();
            glFunc.ClearColor(0.4f, 0.1f, 0f, 1.0f);
            glFunc.Clear(MaskBufferBit.COLOR | MaskBufferBit.DEPTH);

            s.Use();

            vao.Bind(0);

            t.LoadTexture(0, i);

            glFunc.DrawElements(GeometryType.TRIANGLES,6,TypeCode.UInt32,IntPtr.Zero);
            //glFunc.DrawElements(GeometryType.LINES, 6, TypeCode.UInt32, IntPtr.Zero);
            BlueprintPipeline.SkipAll(output);

            PollEvents();
            SwapBuffers();
        }

        protected override void ProcessInput()
        {

        }
    }
}