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 static ConcurrentQueue<IntPtr> glActionQueue;
        private static GLparamQueue paramQueue;
        private FrameTimeoutException refreshSignal = new();

        private IntPtr SwapBufferPtr = (IntPtr)(delegate*<IntPtr, void>)&InternalIO.glfwSwapBuffers;

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

        internal static GLparamQueue ParamQueue
        {
            get { return paramQueue; }
        }

        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, glHandle texture)
        {
            M128 m = new M128 { IntPtr1 = (IntPtr)texture.valuePtr };
            m.UInt32[0] = (uint)type;
            paramQueue.Enqueue(m);
            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);
        }

        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.glfwCreateWindow(
                    width, height, tittleBytes, monitor, IntPtr.Zero);
            }
            else
            {
                windowPtr = InternalIO.glfwCreateWindow(
                    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);
        }

        unsafe void IglFunc.DeleteVertexArrays(glHandleSet arrays)
        {
            M128 m = new() { IntPtr1 = (IntPtr)arrays.handle };
            m.Int32[0] = arrays.length;
            paramQueue.Enqueue(m);
            glActionQueue.Enqueue(DeleteVertexArrayPtr);
        }

        void IglFunc.DrawElements(GepmetryType mode, uint count, TypeCode type, IntPtr ptr)
        {
            uint a;
            switch (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 {type} method DrawElements. " +
                        $"Only {TypeCode.Byte}, {TypeCode.UInt16}, {TypeCode.UInt32} types are suporrted.",
                        LogType.Error);
                    return;
            }
            paramQueue.Enqueue((uint)mode, count, a);
            paramQueue.Enqueue(ptr);
            glActionQueue.Enqueue(DrawElementsPtr);
        }

        unsafe glHandleSet IglFunc.GenBuffers(int count)
        {
            glHandleSet h = new glHandleSet(count);
            M128 m = default; m.UInt32[2] = (uint)count; m.IntPtr0 = (IntPtr)h.handle;
            paramQueue.Enqueue(m);
            glActionQueue.Enqueue(GenBufferPtr);
            return h;
        }

        unsafe glHandleSet IglFunc.GenTextures(int count)
        {
            glHandleSet h = new glHandleSet(count);
            M128 m = default; m.UInt32[2] = (uint)count; m.IntPtr0 = (IntPtr)h.handle;
            paramQueue.Enqueue(m);
            glActionQueue.Enqueue(GenTexturesPtr);
            return h;
        }

        unsafe glHandleSet IglFunc.GenVertexArrays(int count)
        {
            glHandleSet h = new glHandleSet(count);
            M128 m = default; m.UInt32[2] = (uint)count; m.IntPtr0 = (IntPtr)h.handle;
            paramQueue.Enqueue(m);
            glActionQueue.Enqueue(GenTexturesPtr);
            return h;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        unsafe glSHandle IglFunc.GetUniformLocation(glHandle program, string ptr)
        {
            glSHandle h = glSHandle.Alloc(0);
            M128 m;
            m.IntPtr0 = program.Handle;
            m.IntPtr1 = GCHandle.Alloc(Encoding.UTF8.GetBytes(ptr)).AddrOfPinnedObject();
            paramQueue.Enqueue(m);
            paramQueue.Enqueue((IntPtr)h.valuePtr);
            glActionQueue.Enqueue(GetUniformLocationPtr);
            return h;
        }

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

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

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

        void IglFunc.SetBufferData<T>(BufferType bufferType, T bufferData, BufferUsage usage)
        {
            paramQueue.Enqueue((uint)bufferType, (uint)usage);
            paramQueue.Enqueue((IntPtr)sizeof(T), GCHandle.Alloc(bufferData).AddrOfPinnedObject());
            glActionQueue.Enqueue(BufferDataPtr);
        }

        void IglFunc.SetBufferData<T>(BufferType bufferType, T[] bufferArray, BufferUsage usage)
        {
            paramQueue.Enqueue((uint)bufferType, (uint)usage);
            paramQueue.Enqueue((IntPtr)(Marshal.SizeOf<T>() * bufferArray.Length), GCHandle.Alloc(bufferArray).AddrOfPinnedObject());
            glActionQueue.Enqueue(BufferDataPtr);
        }

        void IglFunc.SetVertexAttribute(uint index, int size, TypeCode t, bool normalized, uint stride, int pointer)
        {
            uint type = InternalIO.GLtype[t];
            paramQueue.Enqueue(index, type, stride);
            paramQueue.Enqueue(size, normalized ? 1 : 0, pointer);
            glActionQueue.Enqueue(SetVertexArrayPtr);
        }

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

        }

        unsafe void IglFunc.TextureImage2d<T>(int target, int level, uint internalformat, uint width, uint height, uint format, uint type, T[] pixels)
        {
            IntPtr source = GCHandle.Alloc(pixels, GCHandleType.Pinned).AddrOfPinnedObject();
            paramQueue.Enqueue(source);
            paramQueue.Enqueue((uint)level, internalformat, width, height);
            paramQueue.Enqueue((uint)target, format, type);
            glActionQueue.Enqueue(textureImage2dPtr);
        }

        void IglFunc.TextureParameter(int target, uint pname, int param)
        {
            M128 m = default;
            m.Int32[0] = target;
            m.UInt32[2] = pname;
            m.Int32[3] = param;
            paramQueue.Enqueue(m);
            glActionQueue.Enqueue(TextureParameterPtr);
        }

        void IglFunc.UseProgram(glHandle program)
        {
            paramQueue.Enqueue((IntPtr)program.valuePtr);
            glActionQueue.Enqueue(UseProgramPtr);
        }

        void IglFunc.Viewport(int x, int y, uint width, uint height)
        {
            Vec4d v = new Vec4d(x, y, (int)width, (int)height);
            paramQueue.Enqueue(v);
            glActionQueue.Enqueue(ViewPortPtr);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        internal void frameworkHandleEnqueue(IntPtr methodHandle, params M128[] param)
        {
            glActionQueue.Enqueue(methodHandle);
            foreach (M128 item in param)
            {
                paramQueue.Enqueue(item);
            }
        }
    }
}