using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Threading.Tasks;
using OpenTK;
using OpenTK.Graphics.OpenGL;
using GL_EditorFramework.GL_Core;
using GL_EditorFramework.Interfaces;
using GL_EditorFramework.EditorDrawables;
using Switch_Toolbox.Library.IO;

namespace Switch_Toolbox.Library.Rendering
{
    public class DrawableSkybox : AbstractGlDrawable
    {
        ShaderProgram defaultShaderProgram;

        public override void Prepare(GL_ControlModern control)
        {
            string pathFrag = System.IO.Path.Combine(Runtime.ExecutableDir, "Shader", "HDRSkyBox") + "\\HDRSkyBox.frag";
            string pathVert = System.IO.Path.Combine(Runtime.ExecutableDir, "Shader", "HDRSkyBox") + "\\HDRSkyBox.vert";

            var defaultFrag = new FragmentShader(File.ReadAllText(pathFrag));
            var defaultVert = new VertexShader(File.ReadAllText(pathVert));

            defaultShaderProgram = new ShaderProgram(defaultFrag, defaultVert);
        }
        public override void Prepare(GL_ControlLegacy control)
        {

        }
        public override void Draw(GL_ControlLegacy control, Pass pass)
        {
            if (!Runtime.OpenTKInitialized || pass == Pass.TRANSPARENT)
                return;
        }


        SFGraphics.GLObjects.Textures.TextureCubeMap specularPbr;
        public override void Draw(GL_ControlModern control, Pass pass)
        {
            if (!Runtime.OpenTKInitialized || !Runtime.PBR.UseSkybox || pass == Pass.TRANSPARENT)
                return;

            GL.Enable(EnableCap.DepthTest);
            GL.DepthFunc(DepthFunction.Lequal);

            GL.Enable(EnableCap.LineSmooth);

            GL.Enable(EnableCap.StencilTest);
            GL.StencilOp(StencilOp.Keep, StencilOp.Keep, StencilOp.Replace);
                

            control.CurrentShader = defaultShaderProgram;
            // enable seamless cubemap sampling for lower mip levels in the pre-filter map.
            GL.Enable(EnableCap.TextureCubeMapSeamless);

            Matrix4 proj = Matrix4.Identity;
            Matrix4 rot = Matrix4.CreateFromQuaternion(control.ModelMatrix.ExtractRotation());

            GL.UniformMatrix4(defaultShaderProgram["projection"], false, ref proj);
            GL.UniformMatrix4(defaultShaderProgram["rotView"], false, ref rot);

            if (Runtime.PBR.UseDiffuseSkyTexture)
            {
                //Load Cubemap
                if (RenderTools.diffusePbr != null)
                {
                    GL.ActiveTexture(TextureUnit.Texture0);
                    RenderTools.diffusePbr.Bind();
                }
            }
            else
            {
                //Load Cubemap
                if (RenderTools.specularPbr != null)
                {
                    GL.ActiveTexture(TextureUnit.Texture0);
                    RenderTools.specularPbr.Bind();
                }
            }

            int cubeVBO = 0;

            if (cubeVBO == 0)
            {
                float[] vertices = {
            // back face
            -1.0f, -1.0f, -1.0f,  0.0f,  0.0f, -1.0f, 0.0f, 0.0f, // bottom-left
             1.0f,  1.0f, -1.0f,  0.0f,  0.0f, -1.0f, 1.0f, 1.0f, // top-right
             1.0f, -1.0f, -1.0f,  0.0f,  0.0f, -1.0f, 1.0f, 0.0f, // bottom-right         
             1.0f,  1.0f, -1.0f,  0.0f,  0.0f, -1.0f, 1.0f, 1.0f, // top-right
            -1.0f, -1.0f, -1.0f,  0.0f,  0.0f, -1.0f, 0.0f, 0.0f, // bottom-left
            -1.0f,  1.0f, -1.0f,  0.0f,  0.0f, -1.0f, 0.0f, 1.0f, // top-left
            // front face
            -1.0f, -1.0f,  1.0f,  0.0f,  0.0f,  1.0f, 0.0f, 0.0f, // bottom-left
             1.0f, -1.0f,  1.0f,  0.0f,  0.0f,  1.0f, 1.0f, 0.0f, // bottom-right
             1.0f,  1.0f,  1.0f,  0.0f,  0.0f,  1.0f, 1.0f, 1.0f, // top-right
             1.0f,  1.0f,  1.0f,  0.0f,  0.0f,  1.0f, 1.0f, 1.0f, // top-right
            -1.0f,  1.0f,  1.0f,  0.0f,  0.0f,  1.0f, 0.0f, 1.0f, // top-left
            -1.0f, -1.0f,  1.0f,  0.0f,  0.0f,  1.0f, 0.0f, 0.0f, // bottom-left
            // left face
            -1.0f,  1.0f,  1.0f, -1.0f,  0.0f,  0.0f, 1.0f, 0.0f, // top-right
            -1.0f,  1.0f, -1.0f, -1.0f,  0.0f,  0.0f, 1.0f, 1.0f, // top-left
            -1.0f, -1.0f, -1.0f, -1.0f,  0.0f,  0.0f, 0.0f, 1.0f, // bottom-left
            -1.0f, -1.0f, -1.0f, -1.0f,  0.0f,  0.0f, 0.0f, 1.0f, // bottom-left
            -1.0f, -1.0f,  1.0f, -1.0f,  0.0f,  0.0f, 0.0f, 0.0f, // bottom-right
            -1.0f,  1.0f,  1.0f, -1.0f,  0.0f,  0.0f, 1.0f, 0.0f, // top-right
            // right face
             1.0f,  1.0f,  1.0f,  1.0f,  0.0f,  0.0f, 1.0f, 0.0f, // top-left
             1.0f, -1.0f, -1.0f,  1.0f,  0.0f,  0.0f, 0.0f, 1.0f, // bottom-right
             1.0f,  1.0f, -1.0f,  1.0f,  0.0f,  0.0f, 1.0f, 1.0f, // top-right         
             1.0f, -1.0f, -1.0f,  1.0f,  0.0f,  0.0f, 0.0f, 1.0f, // bottom-right
             1.0f,  1.0f,  1.0f,  1.0f,  0.0f,  0.0f, 1.0f, 0.0f, // top-left
             1.0f, -1.0f,  1.0f,  1.0f,  0.0f,  0.0f, 0.0f, 0.0f, // bottom-left     
            // bottom face
            -1.0f, -1.0f, -1.0f,  0.0f, -1.0f,  0.0f, 0.0f, 1.0f, // top-right
             1.0f, -1.0f, -1.0f,  0.0f, -1.0f,  0.0f, 1.0f, 1.0f, // top-left
             1.0f, -1.0f,  1.0f,  0.0f, -1.0f,  0.0f, 1.0f, 0.0f, // bottom-left
             1.0f, -1.0f,  1.0f,  0.0f, -1.0f,  0.0f, 1.0f, 0.0f, // bottom-left
            -1.0f, -1.0f,  1.0f,  0.0f, -1.0f,  0.0f, 0.0f, 0.0f, // bottom-right
            -1.0f, -1.0f, -1.0f,  0.0f, -1.0f,  0.0f, 0.0f, 1.0f, // top-right
            // top face
            -1.0f,  1.0f, -1.0f,  0.0f,  1.0f,  0.0f, 0.0f, 1.0f, // top-left
             1.0f,  1.0f , 1.0f,  0.0f,  1.0f,  0.0f, 1.0f, 0.0f, // bottom-right
             1.0f,  1.0f, -1.0f,  0.0f,  1.0f,  0.0f, 1.0f, 1.0f, // top-right     
             1.0f,  1.0f,  1.0f,  0.0f,  1.0f,  0.0f, 1.0f, 0.0f, // bottom-right
            -1.0f,  1.0f, -1.0f,  0.0f,  1.0f,  0.0f, 0.0f, 1.0f, // top-left
            -1.0f,  1.0f,  1.0f,  0.0f,  1.0f,  0.0f, 0.0f, 0.0f  // bottom-left        
        };

                GL.GenVertexArrays(1, out cubeVBO);
                GL.GenBuffers(1, out cubeVBO);
                GL.BindBuffer(BufferTarget.ArrayBuffer, cubeVBO);
                GL.BufferData(BufferTarget.ArrayBuffer, 4 * vertices.Length, vertices, BufferUsageHint.StaticDraw);
                GL.BindVertexArray(cubeVBO);
                GL.EnableVertexAttribArray(0);
                GL.VertexAttribPointer(0, 3, VertexAttribPointerType.Float, false, 8 * sizeof(float), (IntPtr)0);
                GL.EnableVertexAttribArray(1);
                GL.VertexAttribPointer(1, 3, VertexAttribPointerType.Float, false, 8 * sizeof(float), (IntPtr)(3 * sizeof(float)));
                GL.EnableVertexAttribArray(2);
                GL.VertexAttribPointer(2, 2, VertexAttribPointerType.Float, false, 8 * sizeof(float), (IntPtr)(6 * sizeof(float)));
                GL.BindBuffer(BufferTarget.ArrayBuffer, 0);
                GL.BindVertexArray(0);

            }
            GL.BindVertexArray(cubeVBO);
            GL.DrawArrays(PrimitiveType.Triangles, 0, 36);
            GL.BindVertexArray(0);
        }
    }
}