using System.Numerics;
using Hexa.NET.ImGui;
using Hexa.NET.ImGuizmo;
using Hexa.NET.ImPlot;
using Hexa.NET.OpenGL;
using HexaGen.Runtime;
using SDL3;

namespace SDL3_TestingSuite.SDL3;

public sealed unsafe class SDL3Window : IDisposable
{
    public readonly nint Window;

    public readonly Vector4 DefaultClearColor = new Vector4(0.06f, 0.06f, 0.06f, 1f);

    private Vector4? _clearColor;
    public Vector4 ClearColor
    {
        get => _clearColor ?? DefaultClearColor;
        set => _clearColor = value;
    }

    public event Action? RenderCallback;

    private ImGuiContextPtr _imGuiContext;
    private ImPlotContextPtr _imPlotContext;

    public bool Disposed => _disposed;
    private bool _disposed;

    private readonly FileSystemWatcher? _watcher;

    private readonly GL _gl;

    public SDL3Window(string name, int posX, int posY, int width, int height, SDL.WindowFlags flags = SDL.WindowFlags.Resizable | SDL.WindowFlags.HighPixelDensity)
    {
        if (!SDL.Init(SDL.InitFlags.Events | SDL.InitFlags.Video | SDL.InitFlags.Gamepad))
            throw new Exception($"SDL_Init failed: {SDL.GetError()}");

        SDL.GLSetAttribute(SDL.GLAttr.ContextFlags, (int)SDL.GLContextFlag.ForwardCompatible);
        SDL.GLSetAttribute(SDL.GLAttr.ContextProfileMask, (int)SDL.GLProfile.Core);
        SDL.GLSetAttribute(SDL.GLAttr.ContextMajorVersion, 3);
        SDL.GLSetAttribute(SDL.GLAttr.ContextMinorVersion, 3);

        SDL.SetHint(SDL.Hints.IMEImplementedUI, "1");

        // Create window & renderer
        SDL.GLSetAttribute(SDL.GLAttr.DoubleBuffer, 1);
        SDL.GLSetAttribute(SDL.GLAttr.DepthSize, 24);
        SDL.GLSetAttribute(SDL.GLAttr.StencilSize, 8);
        Window = SDL.CreateWindow(name, width, height, flags | SDL.WindowFlags.OpenGL);
        if (Window == nint.Zero)
            throw new Exception($"SDL_CreateWindowAndRenderer failed: {SDL.GetError()}");

        nint glContext = SDL.GLCreateContext(Window);
        if (glContext == nint.Zero)
            throw new Exception($"SDL_GL_CreateContext failed: {SDL.GetError()}");

        SDL.GLMakeCurrent(Window, glContext);
        SDL.GLSetSwapInterval(1);

        SDL.SetWindowPosition(Window, posX, posY);
        // SDL.SetRenderVSync(Renderer, 1);
        SDL.ShowWindow(Window);

        // Create ImGui context
        _imGuiContext = ImGui.CreateContext();
        _imPlotContext = ImPlot.CreateContext();
        ImPlot.SetImGuiContext(_imGuiContext);
        ImGuizmo.SetImGuiContext(_imGuiContext);

        ImGuiIOPtr io = ImGui.GetIO();
        io.ConfigFlags |= ImGuiConfigFlags.NavEnableKeyboard | ImGuiConfigFlags.NavEnableGamepad | ImGuiConfigFlags.DockingEnable;
        io.ConfigFlags |= ImGuiConfigFlags.ViewportsEnable;

        io.Fonts.Flags |= ImFontAtlasFlags.NoBakedLines;
        io.Fonts.AddFontDefault();

        try
        {
            string fontsPath = Path.Combine(AppContext.BaseDirectory, "Fonts");
            if (!Path.Exists(fontsPath)) Directory.CreateDirectory(fontsPath);

            _watcher = new FileSystemWatcher(fontsPath);
            _watcher.NotifyFilter = NotifyFilters.FileName | NotifyFilters.CreationTime;
            _watcher.Created += (_, b) =>
            {
                if (!File.Exists(b.FullPath)) return;

                if (Path.GetExtension(b.FullPath) != ".ttf") return;

                ImGui.GetIO().AddFont(b.FullPath);
            };
            _watcher.Deleted += (_, b) =>
            {
                if (Path.GetExtension(b.FullPath) != ".ttf") return;

                ImGui.GetIO().RemoveFont(b.Name);
            };

            _watcher.IncludeSubdirectories = false;
            _watcher.EnableRaisingEvents = true;

            string[] fonts = Directory.GetFiles(fontsPath, "*.ttf", SearchOption.AllDirectories);
            foreach (string font in fonts)
            {
                io.AddFont(font);
            }
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }
        
        _gl = new GL(new BindingsContext(Window, glContext));

        // Init platform and renderer
        ImGuiSDL3Platform.Init(_gl, glContext, Window, this);
        ImGuiSDL3Renderer.Init(_gl, "#version 330");
    }

    public bool ShouldClose;

    public void Run()
    {
        while (!_disposed)
        {
            SDL.PumpEvents();
            
            if (ImGui.GetIO().WantTextInput && !SDL.TextInputActive(Window))
                SDL.StartTextInput(Window);
            else if (!ImGui.GetIO().WantTextInput && SDL.TextInputActive(Window))
                SDL.StopTextInput(Window);

            while (SDL.PollEvent(out SDL.Event ev))
            {
                ImGuiSDL3Platform.ProcessEvent(ev);

                switch ((SDL.EventType)ev.Type)
                {
                    case SDL.EventType.Terminating:
                    case SDL.EventType.WindowCloseRequested:
                    case SDL.EventType.Quit:
                        ShouldClose = true;
                        break;
                }
            }
            
            _gl.MakeCurrent();
            _gl.ClearColor(ClearColor.X, ClearColor.Y, ClearColor.Z, ClearColor.W);
            _gl.Clear(GLClearBufferMask.ColorBufferBit);

            ImGuiSDL3Platform.NewFrame();
            ImGuiSDL3Renderer.NewFrame();
            ImGui.NewFrame();

            RenderCallback?.Invoke();

            ImGuiIOPtr io = ImGui.GetIO();

            ImGui.Render();

            _gl.MakeCurrent();

            ImGuiSDL3Renderer.RenderDrawData(ImGui.GetDrawData());

            if ((io.ConfigFlags & ImGuiConfigFlags.ViewportsEnable) != 0)
            {
                ImGui.UpdatePlatformWindows();
                ImGui.RenderPlatformWindowsDefault();
            }
            
            _gl.MakeCurrent();
            _gl.SwapBuffers();

            if (ShouldClose)
            {
                Dispose();
                break;
            }
        }

        if (!_disposed)
            Dispose();
    }

    ~SDL3Window()
    {
        Dispose(false);
    }

    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }

    private void Dispose(bool disposing)
    {
        if (_disposed) return;
        _disposed = true;

        if (disposing)
        {
            if (_imGuiContext.Handle != null)
            {
                ImGui.SetCurrentContext(_imGuiContext);
            }
            if (_imPlotContext.Handle != null)
            {
                ImPlot.SetCurrentContext(_imPlotContext);
            }

            ImGuiSDL3Renderer.Dispose();
            ImGuiSDL3Platform.Dispose();

            RenderCallback = null;
        }

        if (_imGuiContext.Handle != null)
        {
            ImGui.SetCurrentContext(null);
            ImGui.DestroyContext(_imGuiContext);
            _imGuiContext = null;
        }
        if (_imPlotContext.Handle != null)
        {
            ImPlot.SetCurrentContext(null);
            ImPlot.DestroyContext(_imPlotContext);
            _imPlotContext = null;
        }

        // if (Renderer != nint.Zero)
        // {
        //     SDL.DestroyRenderer(Renderer);
        // }

        if (Window != nint.Zero)
        {
            SDL.DestroyWindow(Window);
        }
    }

}

public unsafe class BindingsContext : IGLContext
{
    private readonly nint window;
    private readonly nint context;

    public BindingsContext(nint window, nint context)
    {
        this.window = window;
        this.context = context;
    }

    public nint Handle => window;

    public bool IsCurrent => SDL.GLGetCurrentContext() == context;

    public void Dispose() { }

    public nint GetProcAddress(string procName)
    {
        return (nint)SDL.GLGetProcAddress(procName).GetPtrForDelegate();
    }

    public bool IsExtensionSupported(string extensionName)
    {
        return SDL.GLExtensionSupported(extensionName);
    }

    public void MakeCurrent()
    {
        SDL.GLMakeCurrent(window, context);
    }

    public void SwapBuffers()
    {
        SDL.GLSwapWindow(window);
    }

    public void SwapInterval(int interval)
    {
        SDL.GLSetSwapInterval(interval);
    }

    public bool TryGetProcAddress(string procName, out nint procAddress)
    {
        procAddress = (nint)SDL.GLGetProcAddress(procName).GetPtrForDelegate();
        return procAddress != 0;
    }
}