/*
 * Clutter.
 *
 * An OpenGL based 'interactive canvas' library.
 *
 * Authored By Matthew Allum  <mallum@openedhand.com>
 *
 * Copyright (C) 2006 OpenedHand
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
/**
 * SECTION:clutter-main
 * @short_description: Various 'global' clutter functions.
 *
 * Functions to retrieve various global Clutter resources and other utility
 * functions for mainloops, events and threads
 */


#include "config.h"

#include <stdlib.h>

#include "clutter-main.h"
#include "clutter-feature.h"
#include "clutter-actor.h"
#include "clutter-stage.h"
#include "clutter-private.h"

typedef struct 
{
  GSource  source;
  Display *display;
  GPollFD  event_poll_fd;
} 
ClutterXEventSource;

typedef void (*ClutterXEventFunc) (XEvent *xev, gpointer user_data);

static gboolean __clutter_has_debug = FALSE;
static gboolean __clutter_has_fps   = FALSE;

static ClutterMainContext *ClutterCntx = NULL;

static gboolean  
x_event_prepare (GSource  *source,
		 gint     *timeout)
{
  Display *display = ((ClutterXEventSource*)source)->display;

  *timeout = -1;

  return XPending (display);
}

static gboolean  
x_event_check (GSource *source) 
{
  ClutterXEventSource *display_source = (ClutterXEventSource*)source;
  gboolean         retval;

  if (display_source->event_poll_fd.revents & G_IO_IN)
    retval = XPending (display_source->display);
  else
    retval = FALSE;

  return retval;
}

static gboolean  
x_event_dispatch (GSource    *source,
		  GSourceFunc callback,
		  gpointer    user_data)
{
  Display *display = ((ClutterXEventSource*)source)->display;
  ClutterXEventFunc event_func = (ClutterXEventFunc) callback;
  
  XEvent xev;

  if (XPending (display))
    {
      XNextEvent (display, &xev);

      if (event_func)
	(*event_func) (&xev, user_data);
    }

  return TRUE;
}

static const GSourceFuncs x_event_funcs = {
  x_event_prepare,
  x_event_check,
  x_event_dispatch,
  NULL
};

static void
translate_key_event (ClutterKeyEvent   *event,
		     XEvent            *xevent)
{
  event->type = xevent->xany.type 
    == KeyPress ? CLUTTER_KEY_PRESS : CLUTTER_KEY_RELEASE;
  event->time = xevent->xkey.time;
  event->modifier_state = xevent->xkey.state; /* FIXME: handle modifiers */
  event->hardware_keycode = xevent->xkey.keycode;
  event->keyval = XKeycodeToKeysym(xevent->xkey.display, 
				   xevent->xkey.keycode,
				   0 );	/* FIXME: index with modifiers */
}

static void
translate_button_event (ClutterButtonEvent   *event,
			XEvent               *xevent)
{
  /* FIXME: catch double click */
 CLUTTER_DBG("button event at %ix%i", xevent->xbutton.x, xevent->xbutton.y);

  event->type = xevent->xany.type 
    == ButtonPress ? CLUTTER_BUTTON_PRESS : CLUTTER_BUTTON_RELEASE;
  event->time = xevent->xbutton.time;
  event->x = xevent->xbutton.x;
  event->y = xevent->xbutton.y;
  event->modifier_state = xevent->xbutton.state; /* includes button masks */
  event->button = xevent->xbutton.button;
}

static void
translate_motion_event (ClutterMotionEvent   *event,
			XEvent               *xevent)
{
  event->type = CLUTTER_MOTION;
  event->time = xevent->xbutton.time;
  event->x = xevent->xmotion.x;
  event->y = xevent->xmotion.y;
  event->modifier_state = xevent->xmotion.state;
}

static void
clutter_dispatch_x_event (XEvent  *xevent,
			  gpointer data)
{
  ClutterMainContext *ctx = CLUTTER_CONTEXT ();
  ClutterEvent        event;
  ClutterStage       *stage = ctx->stage;
  gboolean            emit_input_event = FALSE;

  switch (xevent->type)
    {
    case Expose:
      {
	XEvent foo_xev;

	/* Cheap compress */
	while (XCheckTypedWindowEvent(ctx->xdpy, 
				      xevent->xexpose.window,
				      Expose, 
				      &foo_xev));

	/* FIXME: need to make stage an 'actor' so can que
         * a paint direct from there rather than hack here...
	*/
	clutter_actor_queue_redraw (CLUTTER_ACTOR (stage));
      }
      break;
    case KeyPress:
      translate_key_event ((ClutterKeyEvent *) &event, xevent);
      g_signal_emit_by_name (stage, "key-press-event", &event);
      emit_input_event = TRUE;
      break;
    case KeyRelease:
      translate_key_event ((ClutterKeyEvent *) &event, xevent);
      g_signal_emit_by_name (stage, "key-release-event", &event);
      emit_input_event = TRUE;
      break;
    case ButtonPress:
      translate_button_event ((ClutterButtonEvent *) &event, xevent);
      g_signal_emit_by_name (stage, "button-press-event", &event);
      emit_input_event = TRUE;
      break;
    case ButtonRelease:
      translate_button_event ((ClutterButtonEvent *) &event, xevent);
      g_signal_emit_by_name (stage, "button-release-event", &event);
      emit_input_event = TRUE;
      break;
    case MotionNotify:
      translate_motion_event ((ClutterMotionEvent *) &event, xevent);
      g_signal_emit_by_name (stage, "motion-event", &event);
      emit_input_event = TRUE;
      break;
    }

  if (emit_input_event)
    g_signal_emit_by_name (stage, "input-event", &event);

}

static void
events_init()
{
  GMainContext         *gmain_context;
  int                   connection_number;
  GSource              *source;
  ClutterXEventSource  *display_source;

  gmain_context = g_main_context_default ();

  g_main_context_ref (gmain_context);

  connection_number = ConnectionNumber (ClutterCntx->xdpy);
  
  source = g_source_new ((GSourceFuncs *)&x_event_funcs, 
			 sizeof (ClutterXEventSource));

  display_source = (ClutterXEventSource *)source;

  display_source->event_poll_fd.fd     = connection_number;
  display_source->event_poll_fd.events = G_IO_IN;
  display_source->display              = ClutterCntx->xdpy;
  
  g_source_add_poll (source, &display_source->event_poll_fd);
  g_source_set_can_recurse (source, TRUE);

  g_source_set_callback (source, 
			 (GSourceFunc) clutter_dispatch_x_event, 
			 NULL  /* no userdata */, NULL);

  g_source_attach (source, gmain_context);
  g_source_unref (source);
}

static gboolean
clutter_want_fps(void)
{
  return __clutter_has_fps;
}

/**
 * clutter_redraw:
 *
 * FIXME
 */
void
clutter_redraw (void)
{
  ClutterMainContext *ctx = CLUTTER_CONTEXT();
  ClutterStage       *stage = ctx->stage;
  ClutterColor        stage_color;
  
  static GTimer      *timer = NULL; 
  static guint        timer_n_frames = 0;

  /* FIXME: Should move all this into stage...
  */

  CLUTTER_DBG("@@@ Redraw enter @@@");

  clutter_threads_enter ();

  if (clutter_want_fps ())
    {
      if (!timer)
	timer = g_timer_new ();
    }

  clutter_stage_get_color (stage, &stage_color);

  glClearColor(((float) stage_color.red / 0xff * 1.0),
	       ((float) stage_color.green / 0xff * 1.0),
	       ((float) stage_color.blue / 0xff * 1.0),
	       0.0);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
  glDisable(GL_LIGHTING); 
  glDisable(GL_DEPTH_TEST);

  clutter_actor_paint (CLUTTER_ACTOR (stage));

  if (clutter_stage_get_xwindow (stage))
    {
#if 0
      unsigned int retraceCount;
      /* Wait for vertical retrace */
      /* glXGetVideoSyncSGI(&retraceCount); */
      /* glXWaitVideoSyncSGI(2, (retraceCount+1)%2, &retraceCount); */
      glXWaitVideoSyncSGI(1, 0, &retraceCount);
#endif
      glXSwapBuffers(ctx->xdpy, clutter_stage_get_xwindow (stage));  
    }
  else
    {
      glXWaitGL();
      CLUTTER_GLERR();
    }


  if (clutter_want_fps ())
    {
      timer_n_frames++;

      if (g_timer_elapsed (timer, NULL) >= 1.0)
	{
	  g_print ("*** FPS: %i ***\n", timer_n_frames);
	  timer_n_frames = 0;
	  g_timer_start (timer);
	}
    }

  clutter_threads_leave ();

  CLUTTER_DBG("@@@ Redraw leave @@@");
}

/**
 * clutter_main_quit:
 *
 * Terminates the Clutter mainloop.
 */
void
clutter_main_quit (void)
{
  ClutterMainContext *context = CLUTTER_CONTEXT ();

  g_return_if_fail (context->main_loops != NULL);

  g_main_loop_quit (context->main_loops->data);
}

/**
 * clutter_main_level:
 *
 * Retrieves the depth of the Clutter mainloop.
 *
 * Return value: The level of the mainloop.
 */
gint
clutter_main_level (void)
{
  ClutterMainContext *context = CLUTTER_CONTEXT ();

  return context->main_loop_level;
}

/**
 * clutter_main:
 *
 * Starts the Clutter mainloop.
 */
void
clutter_main (void)
{
  ClutterMainContext *context = CLUTTER_CONTEXT ();
  GMainLoop *loop;

  if (!context->is_initialized)
    {
      g_warning ("Called clutter_main() but Clutter wasn't initialised.  "
		 "You must call clutter_init() first.");
      return;
    }

  context->main_loop_level++;

  loop = g_main_loop_new (NULL, TRUE);
  context->main_loops = g_slist_prepend (context->main_loops, loop);

  if (g_main_loop_is_running (context->main_loops->data))
    {
      g_main_loop_run (loop);
    }

  context->main_loops = g_slist_remove (context->main_loops, loop);

  g_main_loop_unref (loop);

  context->main_loop_level--;

  if (context->main_loop_level == 0)
    {
      clutter_actor_destroy (CLUTTER_ACTOR (context->stage));
      g_free (context);
    }
}

/**
 * clutter_threads_enter:
 *
 * Locks the Clutter thread lock.
 */
void
clutter_threads_enter(void)
{
  ClutterMainContext *context = CLUTTER_CONTEXT ();
  
  g_mutex_lock (context->gl_lock);
}

/**
 * clutter_threads_leave:
 *
 * Unlocks the Clutter thread lock.
 */
void
clutter_threads_leave (void)
{
  ClutterMainContext *context = CLUTTER_CONTEXT ();
  
  g_mutex_unlock (context->gl_lock);
}

/**
 * clutter_xdisplay:
 *
 * Retrieves the X display that Clutter is using
 *
 * Return value: A pointer to an X Display structure.
 */
Display*
clutter_xdisplay (void)
{
  return ClutterCntx->xdpy;
}

/**
 * clutter_xscreen:
 *
 * Retrieves the X screen that Clutter is using.
 *
 * Return value: the X screen ID
 */
int
clutter_xscreen (void)
{
  return ClutterCntx->xscreen;
}

/**
 * clutter_root_xwindow:
 *
 * FIXME
 *
 * Return value: FIXME
 */
Window
clutter_root_xwindow (void)
{
  return ClutterCntx->xwin_root;
}

/**
 * clutter_want_debug:
 * 
 * Check if clutter has debugging turned on.
 *
 * Return value: TRUE if debugging is turned on, FALSE otherwise.
 */
gboolean
clutter_want_debug (void)
{
  return __clutter_has_debug;
}

ClutterMainContext*
clutter_context_get_default (void)
{
  if (!ClutterCntx)
    {
      ClutterMainContext *ctx;

      ctx = g_new0 (ClutterMainContext, 1);
      ctx->is_initialized = FALSE;

      ClutterCntx = ctx;
    }

  return ClutterCntx;
}

static gboolean 
is_gl_version_at_least_12 (void)
{     
#define NON_VENDOR_VERSION_MAX_LEN 32
  gchar        non_vendor_version[NON_VENDOR_VERSION_MAX_LEN];
  const gchar *version;
  gint         i = 0;

  version = (const gchar*)glGetString(GL_VERSION);

  while ( ((version[i] <= '9' && version[i] >= '0') || version[i] == '.') 
	  && i < NON_VENDOR_VERSION_MAX_LEN)
    {
      non_vendor_version[i] = version[i];
      i++;
    }

  non_vendor_version[i] = '\0';

  if (strstr (non_vendor_version, "1.0") == NULL
      && strstr (non_vendor_version, "1.0") == NULL)
    return TRUE;

  return FALSE;
}


/**
 * clutter_init:
 * @argc: The number of arguments in @argv
 * @argv: A pointer to an array of arguments.
 *
 * Initialises Clutter.
 *
 * Return value: 1 on success, < 0 on failure.
 */
int
clutter_init (int *argc, char ***argv)
{
  ClutterMainContext *context;
  static gboolean is_initialized = FALSE;

  if (is_initialized)
    return 1;

  context = clutter_context_get_default ();

  if (g_getenv ("CLUTTER_DEBUG"))
    __clutter_has_debug = TRUE;

  if (g_getenv ("CLUTTER_SHOW_FPS"))
    __clutter_has_fps = TRUE;

  g_type_init();

  if (!g_thread_supported ())
    g_thread_init (NULL);

  XInitThreads();

  context->main_loops = NULL;
  context->main_loop_level = 0;

  if ((context->xdpy = XOpenDisplay (g_getenv ("DISPLAY"))) == NULL)
    {
      g_critical ("Unable to connect to X DISPLAY.");
      return -1;
    }

  context->xscreen   = DefaultScreen(context->xdpy);
  context->xwin_root = RootWindow(context->xdpy,
		  		  context->xscreen);

  context->font_map = PANGO_FT2_FONT_MAP (pango_ft2_font_map_new ());
  pango_ft2_font_map_set_resolution (context->font_map, 96.0, 96.0);

  context->gl_lock = g_mutex_new ();

  context->stage = CLUTTER_STAGE (clutter_stage_get_default ());
  g_return_val_if_fail (CLUTTER_IS_STAGE (context->stage), -3);
  g_object_ref_sink (context->stage);

  /* Realize to get context */
  clutter_actor_realize (CLUTTER_ACTOR (context->stage));

  g_return_val_if_fail 
      (CLUTTER_ACTOR_IS_REALIZED(CLUTTER_ACTOR(context->stage)), -4);

  /* At least GL 1.2 is needed for CLAMP_TO_EDGE */
  g_return_val_if_fail(is_gl_version_at_least_12 (), -5);

  /* Check available features */
  clutter_feature_init ();

  events_init ();

  context->is_initialized = TRUE;

  return 1;
}