/* CALLY - The Clutter Accessibility Implementation Library
 *
 * Copyright (C) 2008 Igalia, S.L.
 *
 * Author: Alejandro Piñeiro Iglesias <apinheiro@igalia.com>
 *
 * Based on GailUtil from GAIL
 * Copyright 2001, 2002, 2003 Sun Microsystems Inc.
 *
 * 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:cally-util
 * @Title: CallyUtil
 * @short_description: #AtkUtil implementation
 * @see_also: #ClutterActor
 *
 * #CallyUtil implements #AtkUtil abstract methods. Although it
 * includes the name "Util" it is in fact one of the most important
 * interfaces to be implemented in any ATK toolkit implementation.

 * For instance, it defines atk_get_root(), the method that returns
 * the root object in the hierarchy. Without it, you don't have
 * available any accessible object.
 */

#ifdef HAVE_CONFIG_H
#include "clutter-build-config.h"
#endif

#include <stdlib.h>
#include <string.h>
#include <clutter/clutter.h>

#include "cally-util.h"
#include "cally-root.h"
#include "cally-stage.h"

#define DEFAULT_PASSWORD_CHAR '*'

/* atkutil.h */

static guint                 cally_util_add_key_event_listener	    (AtkKeySnoopFunc listener,
                                                                     gpointer        data);
static void                  cally_util_remove_key_event_listener    (guint remove_listener);
static AtkObject*            cally_util_get_root			    (void);
static const gchar *         cally_util_get_toolkit_name		    (void);
static const gchar *         cally_util_get_toolkit_version          (void);

/* private */
static void                  cally_util_simulate_snooper_install     (void);
static void                  cally_util_simulate_snooper_remove      (void);
static gboolean              cally_key_snooper                       (ClutterActor *actor,
                                                                      ClutterEvent *event,
                                                                      gpointer      user_data);
static void                  cally_util_stage_added_cb               (ClutterStageManager *stage_manager,
                                                                      ClutterStage *stage,
                                                                      gpointer data);
static void                  cally_util_stage_removed_cb             (ClutterStageManager *stage_manager,
                                                                      ClutterStage *stage,
                                                                      gpointer data);
static gboolean              notify_hf                               (gpointer key,
                                                                      gpointer value,
                                                                      gpointer data);
static void                  insert_hf                               (gpointer key,
                                                                      gpointer value,
                                                                      gpointer data);

/* This is just a copy of the Gail one, a shared library or place to
   define it could be a good idea. */
typedef struct _CallyKeyEventInfo CallyKeyEventInfo;

struct _CallyKeyEventInfo
{
  AtkKeySnoopFunc listener;
  gpointer func_data;
};

static AtkObject* root = NULL;
static GHashTable *key_listener_list = NULL;


G_DEFINE_TYPE (CallyUtil, cally_util, ATK_TYPE_UTIL);

static void
cally_util_class_init (CallyUtilClass *klass)
{
  AtkUtilClass *atk_class;
  gpointer data;

  data = g_type_class_peek (ATK_TYPE_UTIL);
  atk_class = ATK_UTIL_CLASS (data);

  atk_class->add_key_event_listener       = cally_util_add_key_event_listener;
  atk_class->remove_key_event_listener    = cally_util_remove_key_event_listener;
  atk_class->get_root                     = cally_util_get_root;
  atk_class->get_toolkit_name             = cally_util_get_toolkit_name;
  atk_class->get_toolkit_version          = cally_util_get_toolkit_version;

  /* FIXME: Instead of create this on the class, I think that would
     worth to implement CallyUtil as a singleton instance, so the
     class methods will access this instance. This will be a good
     future enhancement, meanwhile, just using the same *working*
     implementation used on GailUtil */
}

static void
cally_util_init (CallyUtil *cally_util)
{
  /* instance init: usually not required */
}

/* ------------------------------ ATK UTIL METHODS -------------------------- */

static AtkObject*
cally_util_get_root (void)
{
  if (!root)
    root = cally_root_new ();

  return root;
}

static const gchar *
cally_util_get_toolkit_name (void)
{
  return "clutter";
}

static const gchar *
cally_util_get_toolkit_version (void)
{
  return CLUTTER_VERSION_S;
}

static guint
cally_util_add_key_event_listener (AtkKeySnoopFunc  listener,
                                   gpointer         data)
{
  static guint key = 1;
  CallyKeyEventInfo *event_info = NULL;

  if (!key_listener_list)
  {
    key_listener_list = g_hash_table_new_full (NULL, NULL, NULL, g_free);

    cally_util_simulate_snooper_install ();
  }

  event_info = g_new (CallyKeyEventInfo, 1);
  event_info->listener = listener;
  event_info->func_data = data;

  g_hash_table_insert (key_listener_list, GUINT_TO_POINTER (key++), event_info);
  /* XXX: we don't check to see if n_listeners > MAXUINT */
  return key - 1;
}

static void
cally_util_remove_key_event_listener (guint remove_listener)
{
  if (!g_hash_table_remove (key_listener_list, GUINT_TO_POINTER (remove_listener))) {
    g_warning ("Not able to remove listener with id %i", remove_listener);
  }

  if (g_hash_table_size (key_listener_list) == 0)
    {
      g_hash_table_destroy (key_listener_list);
      key_listener_list = NULL;
      cally_util_simulate_snooper_remove ();
    }
}

/* ------------------------------ PRIVATE FUNCTIONS ------------------------- */

/* Trying to emulate gtk_key_snooper install (a kind of wrapper). This
   could be implemented without it, but I will maintain it in this
   way, so if in the future clutter implements it natively it would be
   easier the transition */
static void
cally_util_simulate_snooper_install (void)
{
  ClutterStageManager *stage_manager = NULL;
  ClutterStage *stage = NULL;
  GSList *stage_list = NULL;
  GSList *iter = NULL;

  stage_manager = clutter_stage_manager_get_default ();
  stage_list = clutter_stage_manager_list_stages (stage_manager);

  for (iter = stage_list; iter != NULL; iter = g_slist_next (iter))
    {
      stage = CLUTTER_STAGE (iter->data);

      g_signal_connect (G_OBJECT (stage), "captured-event",
                        G_CALLBACK (cally_key_snooper), NULL);
    }

  g_signal_connect (G_OBJECT (stage_manager), "stage-added",
                    G_CALLBACK (cally_util_stage_added_cb), cally_key_snooper);
  g_signal_connect (G_OBJECT (stage_manager), "stage-removed",
                    G_CALLBACK (cally_util_stage_removed_cb), cally_key_snooper);

  g_slist_free (stage_list);
}

static void
cally_util_simulate_snooper_remove (void)
{
  ClutterStageManager *stage_manager = NULL;
  ClutterStage *stage = NULL;
  GSList *stage_list = NULL;
  GSList *iter = NULL;
  gint num = 0;

  stage_manager = clutter_stage_manager_get_default ();
  stage_list = clutter_stage_manager_list_stages (stage_manager);

  for (iter = stage_list; iter != NULL; iter = g_slist_next (iter))
    {
      stage = CLUTTER_STAGE (iter->data);

      num += g_signal_handlers_disconnect_by_func (stage, cally_key_snooper, NULL);
    }

  g_signal_handlers_disconnect_by_func (G_OBJECT (stage_manager),
                                        G_CALLBACK (cally_util_stage_added_cb),
                                        cally_key_snooper);

  g_signal_handlers_disconnect_by_func (G_OBJECT (stage_manager),
                                        G_CALLBACK (cally_util_stage_removed_cb),
                                        cally_key_snooper);

#ifdef CALLY_DEBUG
  g_print ("Number of snooper callbacks disconnected: %i\n", num);
#endif
}

static AtkKeyEventStruct *
atk_key_event_from_clutter_event_key (ClutterKeyEvent *clutter_event,
                                      gunichar         password_char)
{
  AtkKeyEventStruct *atk_event = g_new0 (AtkKeyEventStruct, 1);
  gunichar key_unichar;

  switch (clutter_event->type)
    {
    case CLUTTER_KEY_PRESS:
      atk_event->type = ATK_KEY_EVENT_PRESS;
      break;
    case CLUTTER_KEY_RELEASE:
      atk_event->type = ATK_KEY_EVENT_RELEASE;
      break;
    default:
      g_assert_not_reached ();
      return NULL;
    }

  if (password_char)
    atk_event->state = 0;
  else
    atk_event->state = clutter_event->modifier_state;

  /* We emit the clutter keyval. This is not exactly the one expected
     by AtkKeyEventStruct, as it expects a Gdk-like event, with the
     modifiers applied. But to avoid a dependency to gdk, we delegate
     that on the AT application.
     More information: Bug 1952 and bug 2072
  */
  if (password_char)
    atk_event->keyval = clutter_unicode_to_keysym (password_char);
  else
    atk_event->keyval = clutter_event->keyval;

  /* It is expected to store a key defining string here (ie "Space" in
     case you press a space). Anyway, there are no function on clutter
     to obtain that, and we want to avoid a gdk dependency here, so we
     delegate on the AT application to obtain that string using the
     rest of the data on the ATK event struct.

     More information: Bug 1952 and 2072
  */

  if (password_char)
    key_unichar = password_char;
  else
    key_unichar = clutter_event_get_key_unicode ((ClutterEvent *) clutter_event);

  if (g_unichar_validate (key_unichar) && !g_unichar_iscntrl (key_unichar))
    {
      GString *new = NULL;

      new = g_string_new ("");
      new = g_string_insert_unichar (new, 0, key_unichar);
      atk_event->string = new->str;
      g_string_free (new, FALSE);
    }
  else
    atk_event->string = NULL;

  atk_event->length = 0;

  /* Computing the hardware keycode from the password-char is
     difficult. But we are in a password situation. We are already a
     unichar that it is not the original one. Providing a "almost
     real" keycode is irrelevant */
  if (password_char)
    atk_event->keycode = 0;
  else
    atk_event->keycode = clutter_event->hardware_keycode;

  atk_event->timestamp = clutter_event->time;

#ifdef CALLY_DEBUG

  g_debug ("CallyKeyEvent:\tsym 0x%x\n\t\tmods %x\n\t\tcode %u\n\t\ttime %lx \n\t\tstring %s\n",
	   (unsigned int) atk_event->keyval,
	   (unsigned int) atk_event->state,
	   (unsigned int) atk_event->keycode,
	   (unsigned long int) atk_event->timestamp,
           atk_event->string);
#endif

  return atk_event;
}


static gboolean
notify_hf (gpointer key, gpointer value, gpointer data)
{
  CallyKeyEventInfo *info = (CallyKeyEventInfo *) value;
  AtkKeyEventStruct *key_event = (AtkKeyEventStruct *)data;

  return (*(AtkKeySnoopFunc) info->listener) (key_event, info->func_data) ? TRUE : FALSE;
}

static void
insert_hf (gpointer key, gpointer value, gpointer data)
{
  GHashTable *new_table = (GHashTable *) data;
  g_hash_table_insert (new_table, key, value);
}


/*
 * 0 if the key of that event is visible, in other case the password
 * char
 */
static gunichar
check_key_visibility (ClutterEvent *event)
{
  ClutterKeyEvent *key_event = (ClutterKeyEvent *)event;
  AtkObject *accessible = clutter_actor_get_accessible (key_event->source);

  g_return_val_if_fail (accessible != NULL, 0);

  if (atk_object_get_role (accessible) != ATK_ROLE_PASSWORD_TEXT)
    return 0;

  /* If it is a clutter text, we use his password char.  Note that
     although at Clutter toolkit itself, only ClutterText exposes a
     password role, nothing prevents on any derived toolkit (like st)
     to create a new actor that can behave like a password entry. And
     the key event will still be emitted here. Although in that case
     we would lose any password char from the derived toolkit, it is
     still better fill this with a default unichar that the original
     one */

  if (CLUTTER_IS_TEXT (key_event->source))
    return clutter_text_get_password_char (CLUTTER_TEXT (key_event->source));
  else
    return DEFAULT_PASSWORD_CHAR;
}

static gboolean
cally_key_snooper (ClutterActor *actor,
                   ClutterEvent *event,
                   gpointer      user_data)
{
  AtkKeyEventStruct *key_event = NULL;
  gint consumed = 0;
  gunichar password_char = 0;

  /* filter key events */
  if ((event->type != CLUTTER_KEY_PRESS) && (event->type != CLUTTER_KEY_RELEASE))
    {
      return FALSE;
    }

  password_char = check_key_visibility (event);

  if (key_listener_list)
    {
      GHashTable *new_hash = g_hash_table_new (NULL, NULL);

      g_hash_table_foreach (key_listener_list, insert_hf, new_hash);
      key_event = atk_key_event_from_clutter_event_key ((ClutterKeyEvent *)event,
                                                        password_char);
      /* func data is inside the hash table */
      consumed = g_hash_table_foreach_steal (new_hash, notify_hf, key_event);
      g_hash_table_destroy (new_hash);

      g_free (key_event->string);
      g_free (key_event);
    }

  return (consumed ? 1 : 0);
}

static void
cally_util_stage_added_cb (ClutterStageManager *stage_manager,
                           ClutterStage *stage,
                           gpointer data)
{
  GCallback cally_key_snooper_cb = G_CALLBACK (data);

  g_signal_connect (G_OBJECT (stage), "captured-event", cally_key_snooper_cb, NULL);
}

static void
cally_util_stage_removed_cb (ClutterStageManager *stage_manager,
                             ClutterStage *stage,
                             gpointer data)
{
  GCallback cally_key_snooper_cb = G_CALLBACK (data);

  g_signal_handlers_disconnect_by_func (stage, cally_key_snooper_cb, NULL);
}

void
_cally_util_override_atk_util (void)
{
  AtkUtilClass *atk_class = ATK_UTIL_CLASS (g_type_class_ref (ATK_TYPE_UTIL));

  atk_class->add_key_event_listener = cally_util_add_key_event_listener;
  atk_class->remove_key_event_listener = cally_util_remove_key_event_listener;
  atk_class->get_root = cally_util_get_root;
  atk_class->get_toolkit_name = cally_util_get_toolkit_name;
  atk_class->get_toolkit_version = cally_util_get_toolkit_version;
}
