using StgSharp.Logic;
using StgSharp.Math;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace StgSharp.Graphics
{
    internal unsafe partial class GLonUpdate : IglFunc
    {
        private IntPtr ActiveTexturePtr = (IntPtr)(delegate*<void>)&InternalActiveTexture;
        private IntPtr AttachShaderPtr = (IntPtr)(delegate*<void>)&InternalAttachShader;
        private IntPtr BindBufferPtr = (IntPtr)(delegate*<void>)&InternalBindBuffer;
        private IntPtr ClearColorPtr = (IntPtr)(delegate*<void>)&InternalClearColor;
        private IntPtr ClearGraphicErrorPtr = (IntPtr)(delegate*<void>)&InternalClearGraphicError;
        private IntPtr CompileShaderPtr = (IntPtr)(delegate*<void>)&InternalCompileShader;
        private IntPtr DeleBufferPtr = (IntPtr)(delegate*<void>)&InternalDeleteBuffer;
        private IntPtr BindTexturePtr = (IntPtr)(delegate*<void>)&InternalBindTexture;
        private IntPtr BindVertexArrayPtr = (IntPtr)(delegate*<void>)&InternalBindVertexArray;
        private IntPtr BufferDataPtr = (IntPtr)(delegate*<void>)&InternalSetBufferData;
        private IntPtr ClearPtr = (IntPtr)(delegate*<void>)&InternalClear;
        private IntPtr CreateProgramPtr = (IntPtr)(delegate*<void>)&InternalCreateProgram;
        private IntPtr CreateProgramSetPtr = (IntPtr)(delegate*<void>)&InternalCreateProgramSet;
        private IntPtr DeleteVertexArrayPtr = (IntPtr)(delegate*<void>)&InternalDeleteVertexArrays;
        private IntPtr DrawElementsPtr = (IntPtr)(delegate*<void>)&InternalDrawElements;
        private IntPtr GenBufferPtr = (IntPtr)(delegate*<void>)&InternalGenBuffers;
        private IntPtr GenTexturesPtr = (IntPtr)(delegate*<void>)&InternalGenTextures;
        private IntPtr GenVertexArraysPtr = (IntPtr)(delegate*<void>)&InternalGenVertexArrays;
        private IntPtr GetUniformLocationPtr = (IntPtr)(delegate*<void>)&InternalGetUniformLocation;
        private IntPtr SetVertexArrayPtr = (IntPtr)(delegate*<void>)&InternalSetVertexAttribute;
        private IntPtr textureImage2dPtr = (IntPtr)(delegate*<void>)&InternalTextureImage2d;
        private IntPtr TextureParameterPtr = (IntPtr)(delegate*<void>)&InternalTextureParameter;
        private IntPtr UseProgramPtr = (IntPtr)(delegate*<void>)&InternalUseProgram;
        private IntPtr ViewPortPtr = (IntPtr)(delegate*<void>)&InternalViewport;

        private static void InternalActiveTexture()
        {
            uint t;
            paramQueue.TryDequeue(out t);
            paramQueue.context->glActiveTexture(t);
        }

        private static void InternalAttachShader()
        {
            uint p, s;
            paramQueue.TryDequeue(out p, out s);
            paramQueue.context->glAttachShader(p, s);
        }

        private static void InternalBindBuffer()
        {
            M128 m = default;
            paramQueue.TryDequeue(out m);
            paramQueue.context->glBindBuffer(m.UInt32[0], *(uint*)m.IntPtr1);
        }

        private static void InternalBindTexture()
        {
            M128 m = default;
            paramQueue.TryDequeue(out m);
            paramQueue.context->glBindTexture(m.UInt32[0], *(uint*)m.IntPtr1);
        }

        private static void InternalBindVertexArray()
        {
            IntPtr i;
            paramQueue.TryDequeue(out i);
            paramQueue.context->glBindVertexArray(*(uint*)i);
        }

        private static void InternalClear()
        {
            uint mt;
            paramQueue.TryDequeue(out mt);
            paramQueue.context->glClear(mt);
        }

        private static void InternalClearColor()
        {
            float r, g, b, a;
            paramQueue.TryDequeue(out r, out g, out b, out a);
            paramQueue.context->glClearColor(r, g, b, a);
        }

        private static void InternalClearGraphicError()
        {
            while (paramQueue.context->glGetError() != 0) { }
        }

        private static void InternalCompileShader()
        {
            IntPtr shaderHandle, codeHandle;
            int count, type;
            paramQueue.TryDequeue(out type, out count);
            for (int i = 0; i < count; i++)
            {
                paramQueue.TryDequeue(out shaderHandle, out codeHandle);
                *(uint*)shaderHandle = InternalIO.InternalLoadShaderCode((byte*)codeHandle, type);
                if (*(uint*)shaderHandle == 0)
                {
                    IntPtr logPtr = InternalIO.InternalReadLog();
                    string log;
                    try
                    {
                        byte[] logByte = new byte[512];
                        Marshal.Copy(logPtr, logByte, 0, 512);
                        log = Encoding.UTF8.GetString(logByte);
                        log = log.Replace("\0", "");

                        bool isUseful = false;
                        foreach (char item in log)
                        {
                            if (!char.IsControl(item))
                            {
                                isUseful = true; break;
                            }
                        }
                        if (!isUseful)
                        {
                            throw new Exception();
                        }
                    }
                    catch (Exception)
                    {
                        log = "Failed to compile shader.\nFailed to get GLSL compiler log";
                    }

                    InternalIO.InternalWriteLog(log, LogType.Error);
                }
                GCHandle.FromIntPtr(codeHandle).Free();
            }
        }

        private static void InternalCreateProgram()
        {
            IntPtr programHandle = default;
            paramQueue.TryDequeue(out programHandle);
            *(uint*)programHandle = paramQueue.context->glCreateProgram();
        }

        private static void InternalCreateProgramSet()
        {
            IntPtr programHandle;
            M128 m = default;
            paramQueue.TryDequeue(out m);
            programHandle = m.IntPtr0;
            for (int i = 0; i < m.Int32[2]; i++)
            {
                *((uint*)programHandle + i) = paramQueue.context->glCreateProgram();
            }
        }

        private static void InternalDeleteBuffer()
        {
            M128 m = default;
            paramQueue.TryDequeue(out m);
            paramQueue.context->glDeleteBuffers(m.UInt32[2], (uint*)m.IntPtr0);
        }

        private static void InternalDeleteVertexArrays()
        {
            M128 m = default;
            paramQueue.TryDequeue(out m);
            paramQueue.context->glDeleteVertexArrays((uint)m.Int32[0], (uint*)m.IntPtr1);
        }

        private static void InternalDrawElements()
        {
            uint mode, count, type;
            IntPtr ptr;
            paramQueue.TryDequeue(out mode, out count, out type);
            paramQueue.TryDequeue(out ptr);
            paramQueue.context->glDrawElements(mode, count, type, (void*)ptr);
        }

        private static void InternalGenBuffers()
        {
            M128 m = default;
            paramQueue.TryDequeue(out m);
            paramQueue.context->glGenBuffers(m.UInt32[2], (uint*)m.IntPtr0);
        }

        private static void InternalGenTextures()
        {
            M128 m = default;
            paramQueue.TryDequeue(out m);
            paramQueue.context->glGenTextures(m.UInt32[2], (uint*)m.IntPtr0);
        }

        private static void InternalGenVertexArrays()
        {
            M128 m = default;
            paramQueue.TryDequeue(out m);
            paramQueue.context->glGenVertexArrays(m.UInt32[2], (uint*)m.IntPtr0);
        }

        private static void InternalGetUniformLocation()
        {
            IntPtr programHandle = default, nameHandle = default, targetHandle = default;
            paramQueue.TryDequeue(out programHandle, out nameHandle);
            paramQueue.TryDequeue(out targetHandle);
            *(int*)targetHandle = paramQueue.context->glGetUniformLocation(*(uint*)programHandle, (byte*)nameHandle);
        }

        private static void InternalSetBufferData()
        {
            uint type = 0, use = 0;
            IntPtr size = default, handle = default;
            paramQueue.TryDequeue(out type, out use);
            paramQueue.TryDequeue(out size, out handle);
            paramQueue.context->glBufferData(type, size, (void*)handle, use);
            GCHandle.FromIntPtr(handle).Free();
        }

        private static void InternalSetVertexAttribute()
        {
            uint index, type, stride;
            int size, normalized, pointer;
            paramQueue.TryDequeue(out index, out type, out stride);
            paramQueue.TryDequeue(out size, out normalized, out pointer);
            paramQueue.context->glVertexAttribPointer(index, size, type, normalized, stride, (void*)pointer);
            paramQueue.context->glEnableVertexAttribArray(index);
        }

        private static void InternalTextureImage2d()
        {
            IntPtr pix = IntPtr.Zero;
            uint target, level, internalFormat, width, height, format, type;
            paramQueue.TryDequeue(out pix);
            paramQueue.TryDequeue(out level, out internalFormat, out width, out height);
            paramQueue.TryDequeue(out target, out format, out type);
            paramQueue.context->glTexImage2D(target, (int)level, internalFormat, width, height, 0, format, type, (void*)pix);
            GCHandle.FromIntPtr(pix).Free();
        }

        private static void InternalTextureParameter()
        {
            M128 m = default;
            paramQueue.TryDequeue(out m);
            paramQueue.context->glTextureParameteri(m.UInt32[0], m.UInt32[2], m.Int32[3]);
        }

        private static void InternalUseProgram()
        {
            IntPtr handle = IntPtr.Zero;
            paramQueue.TryDequeue(out handle);
            paramQueue.context->glUseProgram(*(uint*)handle);
        }

        private static void InternalViewport()
        {
            M128 m = default;
            paramQueue.TryDequeue(out m);
            paramQueue.context->glViewport(m.Int32[0], m.Int32[1], m.UInt32[2], m.UInt32[3]);
        }

        private void InternalMakeContexCurrent(Form form)
        {
            throw new NotImplementedException();
        }

        private void InternalSetValue(Uniform<float, float, float, float> uniform, float v0, float v1, float v2, float v3)
        {
            throw new NotImplementedException();
        }

        private void InternalSwitchContext()
        {
            throw new NotImplementedException();
        }
    }
}