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

namespace StgSharp.Graphics
{


    internal unsafe partial class GLonUpdate : IglFunc
    {
        private ConcurrentQueue<IntPtr> glActionQueue;
        private static GLparamQueue paramQueue;
        private FrameTimeoutException refreshSignal = new();

        internal GLonUpdate(GLcontext* context)
        {
            if (paramQueue == null)
            {
                paramQueue = new GLparamQueue();
            }
            glActionQueue = new ConcurrentQueue<IntPtr>();
        }

        internal ConcurrentQueue<IntPtr> GLactionQueue
        {
            get
            {
                return glActionQueue;
            }
        }
        void IglFunc.ActiveTexture(uint type)
        {
            paramQueue.Enqueue(type);
            glActionQueue.Enqueue(ActiveTexturePtr);
        }


        void IglFunc.AfterAlign(Form form, Action action)
        {
            throw new NotImplementedException();
        }

        void IglFunc.AlignFrame(Form form)
        {
            if (form.timer.alignSign.byte0 > 0)
            {
                throw new InvalidOperationException();
            }
            form.timer.alignSign.byte0++;
            form.timer.WaitNextFrame();
            throw refreshSignal;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        unsafe void IglFunc.AttachShader(glHandle program, glHandle shader)
        {
            paramQueue.Enqueue(program, shader);
            glActionQueue.Enqueue(AttachShaderPtr);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        void IglFunc.BindBuffer(BufferType bufferType, glHandle handle)
        {
            M128 m = default;
            m.UInt32[0] = (uint)bufferType;
            m.IntPtr1 = handle.Handle;
            paramQueue.Enqueue(m);
            glActionQueue.Enqueue(BindBufferPtr);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        void IglFunc.BindTexture(uint type, uint texture)
        {
            paramQueue.Enqueue(type, texture);
            glActionQueue.Enqueue(BindTexturePtr);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        void IglFunc.BindVertexArray(glHandle index)
        {
            paramQueue.Enqueue(index);
            glActionQueue.Enqueue(BindVertexArrayPtr);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        void IglFunc.Clear(MaskBufferBit mask)
        {
            glActionQueue.Enqueue(ClearPtr);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        void IglFunc.ClearColor(float R, float G, float B, float A)
        {
            paramQueue.Enqueue(R, G, B, A);
            glActionQueue.Enqueue(ClearColorPtr);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        void IglFunc.ClearGraphicError()
        {
            glActionQueue.Enqueue(ClearGraphicErrorPtr);
        }

        //TODO:双线程，换运行环境
        void IglFunc.SwitchContext()
        {

        }

        glHandleSet IglFunc.CompileShader(ShaderType shaderType, params string[] shaderCode)
        {
            int l = shaderCode.Length;
            if (l == 0)
            {
                throw new ArgumentException("Should input at least one piece of shader code");
            }
            glHandleSet shaderHandle = new glHandleSet(shaderCode.Length);
            paramQueue.Enqueue((int)shaderType, l);
            for (int i = 0; i < l; i++)
            {
                GCHandle codePtr = GCHandle.Alloc(Encoding.UTF8.GetBytes(shaderCode[i] + '\0'), GCHandleType.Pinned);
                paramQueue.Enqueue((IntPtr)shaderHandle.handle + i, codePtr.AddrOfPinnedObject());
            }
            glActionQueue.Enqueue(CompileShaderPtr);
            return shaderHandle;
        }


        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        glHandle IglFunc.CreateProgram()
        {
            glHandle h = glHandle.Alloc(1);
            paramQueue.Enqueue(h);
            glActionQueue.Enqueue(CreateProgramPtr);
            return h;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        glHandleSet IglFunc.CreateProgram(int count)
        {
            M128 m = default;
            glHandleSet h = new glHandleSet(count);
            m.IntPtr0 = (IntPtr)h.handle;
            m.Int32[2] = count;
            paramQueue.Enqueue(m);
            glActionQueue.Enqueue(CreateProgramSetPtr);
            return h;
        }

        IntPtr IglFunc.CreateWindowHandle(int width, int height, string tittle, IntPtr monitor, Form share)
        {
            byte[] tittleBytes = Encoding.UTF8.GetBytes(tittle);
            IntPtr windowPtr;
            if (share == null)
            {
                windowPtr = InternalIO.glfw.CreateWindow(
                    width, height, tittleBytes, monitor, IntPtr.Zero);
            }
            else
            {
                windowPtr = InternalIO.glfw.CreateWindow(
                    width, height, tittleBytes, monitor, share.windowID);
            }

            if ((long)windowPtr == -1 || (long)windowPtr == -2)
            {
                throw new Exception("Cannot create window instance!");
            }
            else
            {
                return windowPtr;
            }
        }


        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        glHandle IglFunc.CreatGraphicProgram()
        {
            glHandle h = glHandle.Alloc(1);
            paramQueue.Enqueue(h);
            glActionQueue.Enqueue(CreateProgramPtr);
            return h;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        unsafe void IglFunc.DeleteBuffer(glHandle handle)
        {
            M128 m = new M128() { IntPtr0 = handle.Handle };
            m.UInt32[2] = 1;
            paramQueue.Enqueue(m);
            glActionQueue.Enqueue(DeleBufferPtr);
        }

        unsafe void IglFunc.DeleteBuffers(glHandleSet handle)
        {
            M128 m = default;
            m.UInt32[2] = (uint)handle.length;
            m.IntPtr0 = (IntPtr)handle.handle;
            paramQueue.Enqueue(m);
            glActionQueue.Enqueue(DeleBufferPtr);
        }

        //TODO: 从这里开始
        unsafe void IglFunc.DeleteVertexArrays(glHandleSet arrays)
        {
            glActionQueue.Enqueue(
                () =>
                {
                    uint[] target = arrays;
                    fixed (uint* ptr = target)
                    {
                        api->glDeleteVertexArrays(count, ptr);
                    }
                }
                );
        }

        void IglFunc.DrawElements(GepmetryType mode, uint count, Type type, IntPtr ptr)
        {
            uint a;
            switch (Type.GetTypeCode(type))
            {
                case TypeCode.UInt32:
                    a = GLconst.UNSIGNED_INT;
                    break;
                case TypeCode.UInt16:
                    a = GLconst.UNSIGNED_SHORT;
                    break;
                case TypeCode.Byte:
                    a = GLconst.UNSIGNED_BYTE;
                    break;
                default:
                    InternalIO.InternalWriteLog(
                        $"Parameter error in parameter {nameof(type)} method DrawElements. " +
                        $"Only {typeof(uint).Name},{typeof(ushort).Name},{typeof(byte).Name} types are suporrted.",
                        LogType.Error);
                    return;
            }
            glActionQueue.Enqueue(
                () =>
                { api->glDrawElements((uint)mode, count, a, (void*)ptr); }
                );
        }

        unsafe void IglFunc.GenBuffers(uint count, glHandleSet handle)
        {
            glActionQueue.Enqueue(
                () =>
                {
                }
                );
        }

        unsafe void IglFunc.GenTextures(uint count, glHandleSet handle)
        {
            glActionQueue.Enqueue(
                () =>
                {
                }
                );
        }

        unsafe void IglFunc.GenVertexArrays(uint count, glHandleSet ptr)
        {
            glActionQueue.Enqueue(
                () =>
                {
                    api->glGenVertexArrays(count, ptr);
                }
                );
        }

        public void GetGraphicError()
        {
            throw new NotImplementedException();
        }

        void IglFunc.GetGraphicError()
        {
            throw new NotImplementedException();
        }

        unsafe int IglFunc.GetUniformLocation(uint program, byte* ptr)
        {
            int ret = -1;
            glActionQueue.Enqueue(
                () =>
                {
                    int location = api->glGetUniformLocation(program, ptr);
                    Interlocked.Add(ref ret, location + 1);
                }
                );
            while (ret < 0) { }
            return ret;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        bool IglFunc.GetWindowShouldClose(Form form)
        {
            return InternalIO.glfw.WindowShouldClose(form.windowID) == 0;
        }

        public void GLswapBuffers(Form form)
        {
            if (form.windowID == IntPtr.Zero)
            {
                return;
            }
            InternalIO.glfw.SwapBuffers(form.windowID);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        void IglFunc.MakeContexCurrent(Form form)
        {
            if (form.windowID == IntPtr.Zero)
            {
                return;
            }
            InternalIO.glfw.MakeContextCurrent(form.windowID);
        }

        void IglFunc.SetBufferData<T>(BufferType bufferType, T bufferData, BufferUsage usage)
        {
            glActionQueue.Enqueue(
                () =>
                {
                    T data = bufferData;
                    int size = sizeof(T);
                    api->glBufferData(
                        (uint)bufferType,
                        (UIntPtr)size,
                        &data,
                        (uint)usage);
                }
                );
        }

        void IglFunc.SetBufferData<T>(BufferType bufferType, T[] bufferArray, BufferUsage usage)
        {
            glActionQueue.Enqueue(
                () =>
                {
                    int size = bufferArray.Length * Marshal.SizeOf(typeof(T));
                    if (bufferArray == null)
                    {
                        return;
                    }
                    fixed (void* bufferPtr = bufferArray)
                        api->glBufferData(
                            (uint)bufferType,
                            (UIntPtr)size,
                            bufferPtr,
                            (uint)usage);
                }
                );
        }

        void IglFunc.SetFrameBufferSizeCallback(IntPtr id, FrameBufferSizeHandler handler)
        {
            IntPtr handlerPtr = Marshal.GetFunctionPointerForDelegate(handler);
            InternalIO.glfw.SetFramebufferSizeCallback(id, handlerPtr);
        }

        void IglFunc.SetVertexAttribute(uint index, int size, Type t, bool normalized, uint stride, int pointer)
        {
            glActionQueue.Enqueue(
                () =>
                {
                    uint type = InternalIO.GLtype[t];
                    api->glVertexAttribPointer(index, size, type, normalized, stride, (void*)pointer);
                    api->glEnableVertexAttribArray(index);
                }
                );
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        unsafe void IglFunc.SetWindowShouldClose(Form form, bool mark)
        {
            InternalIO.glfw.SetWindowShouldClose(form.windowID, mark ? 1 : 0);
        }
        void IglFunc.SwapBuffers(Form form)
        {
            glActionQueue.Enqueue(
                () =>
                {
                    if (form.windowID == IntPtr.Zero)
                    {
                        return;
                    }
                    InternalIO.glfw.SwapBuffers(form.windowID);
                }
                );
        }

        unsafe void IglFunc.TextureImage2d(uint target, int level, uint internalformat, uint width, uint height, uint format, uint type, void* pixels)
        {
            glActionQueue.Enqueue(
                () =>
                {
                    api->glTexImage2D(target, level, internalformat, width, height, 0, format, type, pixels);
                }
                );
        }

        void IglFunc.TextureParameter(uint target, uint pname, int param)
        {
            glActionQueue.Enqueue(
                () =>
                {
                    api->glTextureParameteri(target, pname, param);
                }
                );
        }

        void IglFunc.UseProgram(uint rogram)
        {
            glActionQueue.Enqueue(
                () =>
                {
                    api->glUseProgram(rogram);
                }
                );
        }

        void IglFunc.Viewport(int x, int y, uint width, uint height)
        {
            glActionQueue.Enqueue(
                () =>
                {
                    api->glViewport(x, y, width, height);
                }
                );
        }
    }
}