using StgSharp.Geometries;
using StgSharp.Graphics;
using StgSharp.Math;
using StgSharp.Math.Linear;
using System;
using System.Diagnostics;
using System.IO;
using System.Numerics;
using System.Runtime.InteropServices;
using System.Text;

namespace StgSharp
{

    public class StgSharpDemoForm : Form
    {
        Uniform<float, float, float> color;
        ElementBuffer ebo;
        Uniform<int> ourTexture;
        Uniform<int> ourTexture2;
        Shader shader;
        Texture texture;
        VertexArray vao;
        VertexBuffer vbo;

        public static unsafe void ProcessInput(IntPtr windowPtr)
        {
            if (InternalIO.glfw.GetKey(windowPtr, (int)Operation.Key.ESCAPE)
                == KeyStatus.PRESS)
            {
                InternalIO.glfw.SetWindowShouldClose(windowPtr, 1);
            }
        }

        public override void Deinit(object[] args, IglFunc GL)
        {
            /**/
            vao.Dispose();
            vbo.Dispose();
            ebo.Dispose();
            /**/

            InternalIO.glfw.Terminate();
        }

        public unsafe void FormSizeCallback(IntPtr window, int width, int height)
        {
            GL.Viewport(0, 0, width, height);
        }

        public override void Init(object[] args, IglFunc GL)
        {

            InternalIO.InternalWriteLog("\n\n\n", "Program start", LogType.Info);

            Platform.InitGL(4, 6);

            InitForm(800, 600, "Hello, STG#!", IntPtr.Zero, null);
            MakeAsCurrentContext();
            SetSizeLimit(800, 600, 800, 600);
            GL.SetFrameBufferSizeCallback(windowID, FormSizeCallback);

            this.LoadGLapi(null);

            shader = CreateShader();
            shader.CompileVertexShader(
                File.ReadAllText("Shader\\vertex.vert")
                );
            shader.CompileFragmentShader(
                File.ReadAllText("Shader\\fragment.frag")
                );
            shader.Link();

            Triangle tri = new Triangle(
                -0.5f, -0.3f, 0.0f,
                0.5f, -0.5f, 0.0f,
                0.0f, 0.5f, 0.0f
                );

            Rectangle rec = new Rectangle(
                -0.5f, 0.5f, 0.0f,
                0.5f, 0.5f, 0.0f,
                0.5f, -0.5f, 0.0f,
                -0.5f, -0.5f, 0.0f
                );

            Polygon5 polygon = new Polygon5(
                -0.4f, 0.5f, 0.0f,
                0.5f, 0.5f, 0.0f,
                0.6f, -0.5f, 0.0f,
                0, -1, 0,
                -0.7f, -0.5f, 0.0f
                );


            vao = new VertexArray(1);
            vbo = new VertexBuffer(2);
            ebo = new ElementBuffer(1);
            texture = CreateTexture(2);


            float[] texCoord = {
                0.0f, 0.0f,
                1.0f, 0.0f,
                1.0f, 1.0f,
                0.0f, 1.0f };

            GL.BindVertexArray(vao[0]);

            ebo.SetValue(0, rec.Indices, BufferUsage.STATIC_DRAW);

            vbo.SetValue(0, rec.VertexBuffer, BufferUsage.STATIC_DRAW);
            GL.SetVertexAttribute(0, 3, typeof(float), false, 4 * sizeof(float), 0);

            vbo.SetValueArray(1, texCoord, BufferUsage.STATIC_DRAW);
            GL.SetVertexAttribute(2, 2, typeof(float), false, 2 * sizeof(float), 0);

            /**/
            GL.BindBuffer(BufferType.ARRAY_BUFFER, 0);
            vao.BindNull();
            /**/

            texture.Bind2D(0);
            texture.Set2dWrapProperty(Wrap.Repeat, Wrap.Repeat);
            texture.Set2dFilterProperty(Filter.Nearest, Filter.Nearest);
            texture.LoadTexture(0, "Shader\\Image1.png", null);

            texture.Bind2D(1);
            texture.Set2dWrapProperty(Wrap.Repeat, Wrap.Repeat);
            texture.Set2dFilterProperty(Filter.Nearest, Filter.Nearest);
            texture.LoadTexture(1, "Shader\\awesomeface.png", null);


            //color = GetUniform<float, float, float>(shader, "color");

            shader.Use();
            /**/
            //ourTexture = GetUniform<int>(shader, "ourTexture");
            GL.SetValue(ourTexture, 0);
            //ourTexture2 = GetUniform<int>(shader, "ourTexture2");
            GL.SetValue(ourTexture2, 1);
            /**/

        }

        public override void OnRenderFrame(object[] args, IglFunc GL)
        {
        }

        public override void OnUpdateFrame(object[] args, IglFunc GL)
        {

            ProcessInput(windowID);

            GL.ClearColor(0.333f, 0.555f, 0.555f, 1.0f);
            //GL.api.Clear(GLconst.COLOR_BUFFER_BIT);
            GL.Clear(MaskBufferBit.COLOR);

            vao.Bind(0);
            shader.Use();

            /**/
            texture.Activate(TextureUnit.Unit0);
            texture.Bind2D(0);
            texture.Activate(TextureUnit.Unit1);
            texture.Bind2D(1);
            /**/

            float time = (float)InternalIO.glfw.GetTime();
            GL.SetValue(color,
                0.5f + MathF.Sin(time),
                0.5f + MathF.Sin(time/* + 0.667f * 3.14f/**/),
                0.5f + MathF.Sin(time/* - 0.667f * 3.14f/**/)
                );

            vao.Bind(0);


            AlignFrame(this, () =>
            {
                GL.DrawElements(GepmetryType.TRIANGLES, 6, typeof(uint), IntPtr.Zero);

                vao.BindNull();

                InternalIO.glfw.SwapBuffers(windowID);
                InternalIO.glfw.PollEvents();
            });

        }
    }

    internal static class Program
    {

        internal unsafe static void Main(string[] args)
        {
            try
            {
                StgSharpDemoForm demoForm = new StgSharpDemoForm();
                demoForm.Show(null);
            }
            catch (Exception ex)
            {
                InternalIO.InternalWriteLog(
                    ex.Message + "\n" + ex.StackTrace,
                    LogType.Error);
            }
        }


        [DllImport(InternalIO.SSC_libname, EntryPoint = "printShaderCode",
            CallingConvention = CallingConvention.Cdecl)]
        internal extern unsafe static void PrintShader(byte** shadercode);


    }
}