using OpenTK.Graphics.OpenGL;
using Ryujinx.Common.Configuration;
using Ryujinx.Graphics.OpenGL;
using Ryujinx.Input.HLE;
using SPB.Graphics;
using SPB.Graphics.OpenGL;
using SPB.Platform;
using SPB.Platform.GLX;
using SPB.Platform.WGL;
using SPB.Windowing;
using System;
using System.Runtime.InteropServices;

namespace Ryujinx.Ui
{
    public class GlRenderer : RendererWidgetBase
    {
        private GraphicsDebugLevel _glLogLevel;

        private bool _initializedOpenGL;

        private OpenGLContextBase _openGLContext;
        private SwappableNativeWindowBase _nativeWindow;

        public GlRenderer(InputManager inputManager, GraphicsDebugLevel glLogLevel) : base(inputManager, glLogLevel)
        {
            _glLogLevel = glLogLevel;
        }

        protected override bool OnDrawn(Cairo.Context cr)
        {
            if (!_initializedOpenGL)
            {
                IntializeOpenGL();
            }

            return true;
        }

        private void IntializeOpenGL()
        {
            _nativeWindow = RetrieveNativeWindow();

            Window.EnsureNative();

            _openGLContext = PlatformHelper.CreateOpenGLContext(GetGraphicsMode(), 3, 3, _glLogLevel == GraphicsDebugLevel.None ? OpenGLContextFlags.Compat : OpenGLContextFlags.Compat | OpenGLContextFlags.Debug);
            _openGLContext.Initialize(_nativeWindow);
            _openGLContext.MakeCurrent(_nativeWindow);

            // Release the GL exclusivity that SPB gave us as we aren't going to use it in GTK Thread.
            _openGLContext.MakeCurrent(null);

            WaitEvent.Set();

            _initializedOpenGL = true;
        }

        private SwappableNativeWindowBase RetrieveNativeWindow()
        {
            if (OperatingSystem.IsWindows())
            {
                IntPtr windowHandle = gdk_win32_window_get_handle(Window.Handle);

                return new WGLWindow(new NativeHandle(windowHandle));
            }
            else if (OperatingSystem.IsLinux())
            {
                IntPtr displayHandle = gdk_x11_display_get_xdisplay(Display.Handle);
                IntPtr windowHandle = gdk_x11_window_get_xid(Window.Handle);

                return new GLXWindow(new NativeHandle(displayHandle), new NativeHandle(windowHandle));
            }

            throw new NotImplementedException();
        }

        [DllImport("libgdk-3-0.dll")]
        private static extern IntPtr gdk_win32_window_get_handle(IntPtr d);

        [DllImport("libgdk-3.so.0")]
        private static extern IntPtr gdk_x11_display_get_xdisplay(IntPtr gdkDisplay);

        [DllImport("libgdk-3.so.0")]
        private static extern IntPtr gdk_x11_window_get_xid(IntPtr gdkWindow);

        private static FramebufferFormat GetGraphicsMode()
        {
            return Environment.OSVersion.Platform == PlatformID.Unix ? new FramebufferFormat(new ColorFormat(8, 8, 8, 0), 16, 0, ColorFormat.Zero, 0, 2, false) : FramebufferFormat.Default;
        }

        public override void InitializeRenderer()
        {
            // First take exclusivity on the OpenGL context.
            ((OpenGLRenderer)Renderer).InitializeBackgroundContext(SPBOpenGLContext.CreateBackgroundContext(_openGLContext));

            _openGLContext.MakeCurrent(_nativeWindow);

            GL.ClearColor(0, 0, 0, 1.0f);
            GL.Clear(ClearBufferMask.ColorBufferBit);
            SwapBuffers(0);
        }

        public override void SwapBuffers(object image)
        {
            if((int)image != 0)
            {
                // The game's framebruffer is already bound, so blit it to the window's backbuffer
                GL.BindFramebuffer(FramebufferTarget.DrawFramebuffer, 0);

                GL.Clear(ClearBufferMask.ColorBufferBit);
                GL.ClearColor(0, 0, 0, 1);

                GL.BlitFramebuffer(0,
                    0,
                    WindowWidth,
                    WindowHeight,
                    0,
                    0,
                    WindowWidth,
                    WindowHeight,
                    ClearBufferMask.ColorBufferBit,
                    BlitFramebufferFilter.Linear);
            }

            _nativeWindow.SwapBuffers();
        }

        protected override string GetGpuBackendName()
        {
            return "OpenGL";
        }

        protected override void Dispose(bool disposing)
        {
            // Try to bind the OpenGL context before calling the shutdown event
            try
            {
                _openGLContext?.MakeCurrent(_nativeWindow);
            }
            catch (Exception) { }

            Device.DisposeGpu();
            NpadManager.Dispose();

            // Unbind context and destroy everything
            try
            {
                _openGLContext?.MakeCurrent(null);
            }
            catch (Exception) { }

            _openGLContext.Dispose();
        }
    }
}