/*
 * 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 GMainLoop *pipeline_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 gchar *video_sink = NULL;
static GstElement *sink = NULL;
static gboolean run_thread = FALSE;

static LONG prev_style = 0;
static RECT prev_rect = { 0, };

static gint x = 0;
static gint y = 0;
static gint width = 320;
static gint height = 240;

typedef struct
{
  GThread *thread;
  HANDLE event_handle;
  HANDLE console_handle;
  gboolean closing;
  GMutex lock;
} Win32KeyHandler;

static Win32KeyHandler *win32_key_handler = NULL;

#define DEFAULT_VIDEO_SINK "d3d11videosink"

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);

      if (pipeline_loop)
        g_main_loop_quit (pipeline_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;
}

static gpointer
pipeline_runner_func (gpointer user_data)
{
  GstElement *pipeline, *src;
  GstStateChangeReturn sret;
  gint num_repeat = 0;
  GMainContext *context = NULL;
  GMainLoop *this_loop;

  if (run_thread) {
    /* We are in runner thread, create our loop */
    context = g_main_context_new ();
    pipeline_loop = g_main_loop_new (context, FALSE);

    g_main_context_push_thread_default (context);

    this_loop = pipeline_loop;
  } else {
    this_loop = loop;
  }

  /* 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);
    exit (1);
  }

  gst_object_ref_sink (sink);

  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, this_loop, NULL);
        g_source_attach (timeout_source, NULL);
        g_source_unref (timeout_source);
      }

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

    visible = FALSE;
  } while (test_reuse);

  gst_bus_remove_watch (GST_ELEMENT_BUS (pipeline));
  gst_object_unref (pipeline);

  if (run_thread) {
    g_main_context_pop_thread_default (context);
    g_main_context_unref (context);

    g_main_loop_quit (loop);
    g_main_loop_unref (pipeline_loop);
  }

  return NULL;
}

static void
print_keyboard_help (void)
{
  /* *INDENT-OFF* */
  static struct
  {
    const gchar *key_desc;
    const gchar *key_help;
  } key_controls[] = {
    {
      "\342\206\222", "move overlay to right-hand side"}, {
      "\342\206\220", "move overlay to left-hand side"}, {
      "\342\206\221", "move overlay to upward"}, {
      "\342\206\223", "move overlay to downward"}, {
      ">", "increase overlay width"}, {
      "<", "decrease overlay width"}, {
      "+", "increase overlay height"}, {
      "-", "decrease overlay height"}, {
      "r", "reset render rectangle"}, {
      "e", "expose overlay"}, {
      "k", "show keyboard shortcuts"},
  };
  /* *INDENT-ON* */

  guint i, chars_to_pad, desc_len, max_desc_len = 0;

  gst_print ("\n\n%s\n\n", "Interactive mode - keyboard controls:");

  for (i = 0; i < G_N_ELEMENTS (key_controls); ++i) {
    desc_len = g_utf8_strlen (key_controls[i].key_desc, -1);
    max_desc_len = MAX (max_desc_len, desc_len);
  }
  ++max_desc_len;

  for (i = 0; i < G_N_ELEMENTS (key_controls); ++i) {
    chars_to_pad = max_desc_len - g_utf8_strlen (key_controls[i].key_desc, -1);
    gst_print ("\t%s", key_controls[i].key_desc);
    gst_print ("%-*s: ", chars_to_pad, "");
    gst_print ("%s\n", key_controls[i].key_help);
  }
  gst_print ("\n");
}

static gboolean
win32_kb_source_cb (Win32KeyHandler * handler)
{
  HANDLE h_input = handler->console_handle;
  INPUT_RECORD buffer;
  DWORD n;

  if (PeekConsoleInput (h_input, &buffer, 1, &n) && n == 1) {
    ReadConsoleInput (h_input, &buffer, 1, &n);

    if (buffer.EventType == KEY_EVENT && buffer.Event.KeyEvent.bKeyDown) {
      gchar key_val[2] = { 0 };

      switch (buffer.Event.KeyEvent.wVirtualKeyCode) {
        case VK_RIGHT:
          gst_println ("Move xpos to %d", x++);
          gst_video_overlay_set_render_rectangle (GST_VIDEO_OVERLAY (sink),
              x, y, width, height);
          break;
        case VK_LEFT:
          gst_println ("Move xpos to %d", x--);
          gst_video_overlay_set_render_rectangle (GST_VIDEO_OVERLAY (sink),
              x, y, width, height);
          break;
        case VK_UP:
          gst_println ("Move ypos to %d", y--);
          gst_video_overlay_set_render_rectangle (GST_VIDEO_OVERLAY (sink),
              x, y, width, height);
          break;
        case VK_DOWN:
          gst_println ("Move ypos to %d", y++);
          gst_video_overlay_set_render_rectangle (GST_VIDEO_OVERLAY (sink),
              x, y, width, height);
          break;
        default:
          key_val[0] = buffer.Event.KeyEvent.uChar.AsciiChar;
          switch (key_val[0]) {
            case '<':
              gst_println ("Decrease width to %d", width--);
              gst_video_overlay_set_render_rectangle (GST_VIDEO_OVERLAY (sink),
                  x, y, width, height);
              break;
            case '>':
              gst_println ("Increase width to %d", width++);
              gst_video_overlay_set_render_rectangle (GST_VIDEO_OVERLAY (sink),
                  x, y, width, height);
              break;
            case '+':
              gst_println ("Increase height to %d", height++);
              gst_video_overlay_set_render_rectangle (GST_VIDEO_OVERLAY (sink),
                  x, y, width, height);
              break;
            case '-':
              gst_println ("Decrease height to %d", height--);
              gst_video_overlay_set_render_rectangle (GST_VIDEO_OVERLAY (sink),
                  x, y, width, height);
              break;
            case 'r':
              gst_println ("Reset render rectangle by setting -1 width/height");
              gst_video_overlay_set_render_rectangle (GST_VIDEO_OVERLAY (sink),
                  x, y, -1, -1);
              break;
            case 'e':
              gst_println ("Expose overlay");
              gst_video_overlay_expose (GST_VIDEO_OVERLAY (sink));
              break;
            case 'k':
              print_keyboard_help ();
              break;
            default:
              break;
          }
          break;
      }
    }
  }

  return G_SOURCE_REMOVE;
}

static gpointer
win32_kb_thread (gpointer user_data)
{
  Win32KeyHandler *handler = (Win32KeyHandler *) user_data;
  HANDLE handles[2];

  handles[0] = handler->event_handle;
  handles[1] = handler->console_handle;

  while (TRUE) {
    DWORD ret = WaitForMultipleObjects (2, handles, FALSE, INFINITE);
    static guint i = 0;

    if (ret == WAIT_FAILED) {
      g_warning ("WaitForMultipleObject Failed");
      return NULL;
    }

    g_mutex_lock (&handler->lock);
    if (handler->closing) {
      g_mutex_unlock (&handler->lock);

      return NULL;
    }
    g_mutex_unlock (&handler->lock);

    g_idle_add ((GSourceFunc) win32_kb_source_cb, handler);
  }

  return NULL;
}

gint
main (gint argc, gchar ** argv)
{
  WNDCLASSEX wc = { 0, };
  HINSTANCE hinstance = GetModuleHandle (NULL);
  GIOChannel *msg_io_channel;
  GOptionContext *option_ctx;
  GError *error = NULL;
  gchar *title = NULL;
  RECT wr = { 0, 0, 320, 240 };
  gint exitcode = 0;
  gboolean ret;
  GThread *thread = NULL;
  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}
    ,
    {"run-thread", 0, 0, G_OPTION_ARG_NONE, &run_thread,
        "Run pipeline from non-window thread", NULL}
    ,
    {NULL}
  };

  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);

  {
    SECURITY_ATTRIBUTES attrs;

    attrs.nLength = sizeof (SECURITY_ATTRIBUTES);
    attrs.lpSecurityDescriptor = NULL;
    attrs.bInheritHandle = FALSE;

    win32_key_handler = g_new0 (Win32KeyHandler, 1);

    /* create cancellable event handle */
    win32_key_handler->event_handle = CreateEvent (&attrs, TRUE, FALSE, NULL);
    win32_key_handler->console_handle = GetStdHandle (STD_INPUT_HANDLE);
    g_mutex_init (&win32_key_handler->lock);
    win32_key_handler->thread =
        g_thread_new ("key-handler", win32_kb_thread, win32_key_handler);
  }

  gst_println ("Press 'k' to see a list of keyboard shortcuts");

  if (run_thread) {
    thread = g_thread_new ("pipeline-thread",
        (GThreadFunc) pipeline_runner_func, NULL);
    g_main_loop_run (loop);
  } else {
    pipeline_runner_func (NULL);
  }

terminate:
  if (hwnd)
    DestroyWindow (hwnd);

  if (win32_key_handler) {
    g_mutex_lock (&win32_key_handler->lock);
    win32_key_handler->closing = TRUE;
    g_mutex_unlock (&win32_key_handler->lock);

    SetEvent (win32_key_handler->event_handle);
    g_thread_join (win32_key_handler->thread);
    CloseHandle (win32_key_handler->event_handle);

    g_mutex_clear (&win32_key_handler->lock);
    g_free (win32_key_handler);
  }

  gst_clear_object (&sink);
  g_io_channel_unref (msg_io_channel);
  g_main_loop_unref (loop);
  g_free (title);
  g_free (video_sink);

  return exitcode;
}