/*
 * GStreamer
 * Copyright (C) 2019 Seungha Yang <seungha.yang@navercorp.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <gst/gst.h>
#include <gst/video/videooverlay.h>
#include <gst/video/gstvideosink.h>
#include <windows.h>
#include <string.h>

static GMainLoop *loop = NULL;
static gboolean visible = FALSE;
static gboolean test_reuse = FALSE;
static HWND hwnd = NULL;
static gboolean test_fullscreen = FALSE;
static gboolean fullscreen = FALSE;
static LONG prev_style = 0;
static RECT prev_rect = { 0, };

#define DEFAULT_VIDEO_SINK "glimagesink"

static gboolean
get_monitor_size (RECT * rect)
{
  HMONITOR monitor = MonitorFromWindow (hwnd, MONITOR_DEFAULTTONEAREST);
  MONITORINFOEX monitor_info;
  DEVMODE dev_mode;

  monitor_info.cbSize = sizeof (monitor_info);
  if (!GetMonitorInfo (monitor, (LPMONITORINFO) & monitor_info)) {
    return FALSE;
  }

  dev_mode.dmSize = sizeof (dev_mode);
  dev_mode.dmDriverExtra = sizeof (POINTL);
  dev_mode.dmFields = DM_POSITION;
  if (!EnumDisplaySettings
      (monitor_info.szDevice, ENUM_CURRENT_SETTINGS, &dev_mode)) {
    return FALSE;
  }

  SetRect (rect, 0, 0, dev_mode.dmPelsWidth, dev_mode.dmPelsHeight);

  return TRUE;
}

static void
switch_fullscreen_mode (void)
{
  if (!hwnd)
    return;

  fullscreen = !fullscreen;

  gst_print ("Full screen %s\n", fullscreen ? "on" : "off");

  if (!fullscreen) {
    /* Restore the window's attributes and size */
    SetWindowLong (hwnd, GWL_STYLE, prev_style);

    SetWindowPos (hwnd, HWND_NOTOPMOST,
        prev_rect.left,
        prev_rect.top,
        prev_rect.right - prev_rect.left,
        prev_rect.bottom - prev_rect.top, SWP_FRAMECHANGED | SWP_NOACTIVATE);

    ShowWindow (hwnd, SW_NORMAL);
  } else {
    RECT fullscreen_rect;

    /* show window before change style */
    ShowWindow (hwnd, SW_SHOW);

    /* Save the old window rect so we can restore it when exiting
     * fullscreen mode */
    GetWindowRect (hwnd, &prev_rect);
    prev_style = GetWindowLong (hwnd, GWL_STYLE);

    if (!get_monitor_size (&fullscreen_rect)) {
      g_warning ("Couldn't get monitor size");

      fullscreen = !fullscreen;
      return;
    }

    /* Make the window borderless so that the client area can fill the screen */
    SetWindowLong (hwnd, GWL_STYLE,
        prev_style &
        ~(WS_CAPTION | WS_MAXIMIZEBOX | WS_MINIMIZEBOX | WS_SYSMENU |
            WS_THICKFRAME));

    SetWindowPos (hwnd, HWND_NOTOPMOST,
        fullscreen_rect.left,
        fullscreen_rect.top,
        fullscreen_rect.right,
        fullscreen_rect.bottom, SWP_FRAMECHANGED | SWP_NOACTIVATE);

    ShowWindow (hwnd, SW_MAXIMIZE);
  }
}

static LRESULT CALLBACK
window_proc (HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
  switch (message) {
    case WM_DESTROY:
      hwnd = NULL;

      if (loop) {
        g_main_loop_quit (loop);
      }
      return 0;
    case WM_KEYUP:
      if (!test_fullscreen)
        break;

      if (wParam == VK_SPACE)
        switch_fullscreen_mode ();
      break;
    case WM_RBUTTONUP:
      if (!test_fullscreen)
        break;

      switch_fullscreen_mode ();
      break;
    default:
      break;
  }

  return DefWindowProc (hWnd, message, wParam, lParam);
}

static gboolean
bus_msg (GstBus * bus, GstMessage * msg, gpointer user_data)
{
  GstElement *pipeline = GST_ELEMENT (user_data);
  switch (GST_MESSAGE_TYPE (msg)) {
    case GST_MESSAGE_ASYNC_DONE:
      /* make window visible when we have something to show */
      if (!visible && hwnd) {
        ShowWindow (hwnd, SW_SHOW);
        visible = TRUE;
      }

      gst_element_set_state (pipeline, GST_STATE_PLAYING);
      break;
    case GST_MESSAGE_ERROR:{
      GError *err;
      gchar *dbg;

      gst_message_parse_error (msg, &err, &dbg);
      g_printerr ("ERROR %s \n", err->message);
      if (dbg != NULL)
        g_printerr ("ERROR debug information: %s\n", dbg);
      g_clear_error (&err);
      g_free (dbg);
      test_reuse = FALSE;

      g_main_loop_quit (loop);
      break;
    }
    default:
      break;
  }

  return TRUE;
}

static gboolean
msg_cb (GIOChannel * source, GIOCondition condition, gpointer data)
{
  MSG msg;

  if (!PeekMessage (&msg, NULL, 0, 0, PM_REMOVE))
    return G_SOURCE_CONTINUE;

  TranslateMessage (&msg);
  DispatchMessage (&msg);

  return G_SOURCE_CONTINUE;
}

static gboolean
timeout_cb (gpointer user_data)
{
  g_main_loop_quit ((GMainLoop *) user_data);

  return G_SOURCE_REMOVE;
}

gint
main (gint argc, gchar ** argv)
{
  GstElement *pipeline, *src, *sink;
  GstStateChangeReturn sret;
  WNDCLASSEX wc = { 0, };
  HINSTANCE hinstance = GetModuleHandle (NULL);
  GIOChannel *msg_io_channel;
  GOptionContext *option_ctx;
  GError *error = NULL;
  gchar *video_sink = NULL;
  gchar *title = NULL;
  RECT wr = { 0, 0, 320, 240 };
  gint exitcode = 0;
  gboolean ret;
  GOptionEntry options[] = {
    {"videosink", 0, 0, G_OPTION_ARG_STRING, &video_sink,
        "Video sink to use (default is glimagesink)", NULL}
    ,
    {"repeat", 0, 0, G_OPTION_ARG_NONE, &test_reuse,
        "Test reuse video sink element", NULL}
    ,
    {"fullscreen", 0, 0, G_OPTION_ARG_NONE, &test_fullscreen,
        "Test full screen (borderless topmost) mode switching via "
          "\"SPACE\" key or \"right mouse button\" click", NULL}
    ,
    {NULL}
  };
  gint num_repeat = 0;

  option_ctx = g_option_context_new ("WIN32 video overlay example");
  g_option_context_add_main_entries (option_ctx, options, NULL);
  g_option_context_add_group (option_ctx, gst_init_get_option_group ());
  ret = g_option_context_parse (option_ctx, &argc, &argv, &error);
  g_option_context_free (option_ctx);

  if (!ret) {
    g_printerr ("option parsing failed: %s\n", error->message);
    g_clear_error (&error);
    exit (1);
  }

  /* prepare window */
  wc.cbSize = sizeof (WNDCLASSEX);
  wc.style = CS_HREDRAW | CS_VREDRAW;
  wc.lpfnWndProc = (WNDPROC) window_proc;
  wc.hInstance = hinstance;
  wc.hCursor = LoadCursor (NULL, IDC_ARROW);
  wc.lpszClassName = "GstWIN32VideoOverlay";
  RegisterClassEx (&wc);

  if (!video_sink)
    video_sink = g_strdup (DEFAULT_VIDEO_SINK);

  title = g_strdup_printf ("%s - Win32-VideoOverlay", video_sink);

  AdjustWindowRect (&wr, WS_OVERLAPPEDWINDOW, FALSE);
  hwnd = CreateWindowEx (0, wc.lpszClassName,
      title,
      WS_CLIPSIBLINGS | WS_CLIPCHILDREN | WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, CW_USEDEFAULT,
      wr.right - wr.left, wr.bottom - wr.top, (HWND) NULL, (HMENU) NULL,
      hinstance, NULL);

  loop = g_main_loop_new (NULL, FALSE);
  msg_io_channel = g_io_channel_win32_new_messages (0);
  g_io_add_watch (msg_io_channel, G_IO_IN, msg_cb, NULL);

  /* prepare the pipeline */
  pipeline = gst_pipeline_new ("win32-overlay");
  src = gst_element_factory_make ("videotestsrc", NULL);
  sink = gst_element_factory_make (video_sink, NULL);

  if (!sink) {
    g_printerr ("%s element is not available\n", video_sink);
    exitcode = 1;

    goto terminate;
  }

  gst_bin_add_many (GST_BIN (pipeline), src, sink, NULL);
  gst_element_link (src, sink);

  gst_bus_add_watch (GST_ELEMENT_BUS (pipeline), bus_msg, pipeline);

  do {
    gst_print ("Running loop %d\n", num_repeat++);

    gst_video_overlay_set_window_handle (GST_VIDEO_OVERLAY (sink),
        (guintptr) hwnd);

    sret = gst_element_set_state (pipeline, GST_STATE_PAUSED);
    if (sret == GST_STATE_CHANGE_FAILURE) {
      g_printerr ("Pipeline doesn't want to pause\n");
      break;
    } else {
      /* add timer to repeat and reuse pipeline  */
      if (test_reuse) {
        GSource *timeout_source = g_timeout_source_new_seconds (3);

        g_source_set_callback (timeout_source,
            (GSourceFunc) timeout_cb, loop, NULL);
        g_source_attach (timeout_source, NULL);
        g_source_unref (timeout_source);
      }

      g_main_loop_run (loop);
    }
    gst_element_set_state (pipeline, GST_STATE_NULL);

    visible = FALSE;
  } while (test_reuse);

  gst_bus_remove_watch (GST_ELEMENT_BUS (pipeline));

terminate:
  if (hwnd)
    DestroyWindow (hwnd);

  gst_object_unref (pipeline);
  g_io_channel_unref (msg_io_channel);
  g_main_loop_unref (loop);
  g_free (title);
  g_free (video_sink);

  return exitcode;
}