/*

 * Copyright (C) 2009-2011 Nokia <ivan.frade@nokia.com>

 *

 * 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,

 *

 * Authors: Jürg Billeter <juerg.billeter@codethink.co.uk>

 *          Martyn Russell <martyn@lanedo.com>

 *

 * Based on nautilus-search-engine-tracker.c

 */

#include "config.h"

#include <string.h>

#include <gio/gio.h>

#include <gmodule.h>

#include <gdk/gdk.h>

#include <gtk/gtk.h>

#include "gtksearchenginetracker.h"

#define DBUS_SERVICE_RESOURCES   "org.freedesktop.Tracker1"

#define DBUS_PATH_RESOURCES      "/org/freedesktop/Tracker1/Resources"

#define DBUS_INTERFACE_RESOURCES "org.freedesktop.Tracker1.Resources"

#define DBUS_SERVICE_STATUS      "org.freedesktop.Tracker1"

#define DBUS_PATH_STATUS         "/org/freedesktop/Tracker1/Status"

#define DBUS_INTERFACE_STATUS    "org.freedesktop.Tracker1.Status"

/* Time in second to wait for service before deciding it's not available */

#define WAIT_TIMEOUT_SECONDS 1

/* Time in second to wait for query results to come back */

#define QUERY_TIMEOUT_SECONDS 10

/* If defined, we use fts:match, this has to be enabled in Tracker to

 * work which it usually is. The alternative is to undefine it and

 * use filename matching instead. This doesn't use the content of the

 * file however.

 */

#undef FTS_MATCHING

/*

 * GtkSearchEngineTracker object

 */

struct _GtkSearchEngineTrackerPrivate

{

  GDBusConnection *connection;

  GCancellable *cancellable;

  GtkQuery *query;

  gboolean query_pending;

};

G_DEFINE_TYPE (GtkSearchEngineTracker, _gtk_search_engine_tracker, GTK_TYPE_SEARCH_ENGINE);

static void

finalize (GObject *object)

{

  GtkSearchEngineTracker *tracker;

  g_debug ("Finalizing GtkSearchEngineTracker");

  tracker = GTK_SEARCH_ENGINE_TRACKER (object);

  if (tracker->priv->cancellable)

    {

      g_cancellable_cancel (tracker->priv->cancellable);

      g_object_unref (tracker->priv->cancellable);

      tracker->priv->cancellable = NULL;

    }

  if (tracker->priv->query)

    {

      g_object_unref (tracker->priv->query);

      tracker->priv->query = NULL;

    }

  if (tracker->priv->connection)

    {

      g_object_unref (tracker->priv->connection);

      tracker->priv->connection = NULL;

    }

  G_OBJECT_CLASS (_gtk_search_engine_tracker_parent_class)->finalize (object);

}

static GDBusConnection *

get_connection (void)

{

  GDBusConnection *connection;

  GError *error = NULL;

  GVariant *reply;

  /* Normally I hate sync calls with UIs, but we need to return NULL

   * or a GtkSearchEngine as a result of this function.

   */

  connection = g_bus_get_sync (G_BUS_TYPE_SESSION, NULL, &error);

  if (error)

    {

      g_debug ("Couldn't connect to D-Bus session bus, %s", error->message);

      g_error_free (error);

      return NULL;

    }

  /* If connection is set, we know it worked. */

  g_debug ("Finding out if Tracker is available via D-Bus...");

  /* We only wait 1 second max, we expect it to be very fast. If we

   * don't get a response by then, clearly we're replaying a journal

   * or cleaning up the DB internally. Either way, services is not

   * available.

   *

   * We use the sync call here because we don't expect to be waiting

   * long enough to block UI painting.

   */

  reply = g_dbus_connection_call_sync (connection,

                                       DBUS_SERVICE_STATUS,

                                       DBUS_PATH_STATUS,

                                       DBUS_INTERFACE_STATUS,

                                       "Wait",

                                       NULL,

                                       NULL,

                                       G_DBUS_CALL_FLAGS_NONE,

                                       WAIT_TIMEOUT_SECONDS * 1000,

                                       NULL,

                                       &error);

  if (error)

    {

      g_debug ("Tracker is not available, %s", error->message);

      g_error_free (error);

      g_object_unref (connection);

      return NULL;

    }

  g_variant_unref (reply);

  g_debug ("Tracker is ready");

  return connection;

}

static void

get_query_results (GtkSearchEngineTracker *engine,

                   const gchar            *sparql,

                   GAsyncReadyCallback     callback,

                   gpointer                user_data)

{

  g_dbus_connection_call (engine->priv->connection,

                          DBUS_SERVICE_RESOURCES,

                          DBUS_PATH_RESOURCES,

                          DBUS_INTERFACE_RESOURCES,

                          "SparqlQuery",

                          g_variant_new ("(s)", sparql),

                          NULL,

                          G_DBUS_CALL_FLAGS_NONE,

                          QUERY_TIMEOUT_SECONDS * 1000,

                          engine->priv->cancellable,

                          callback,

                          user_data);

}

/* Stolen from libtracker-common */

static GList *

string_list_to_gslist (gchar **strv)

{

  GList *list;

  gsize i;

  list = NULL;

  for (i = 0; strv[i]; i++)

    list = g_list_prepend (list, g_strdup (strv[i]));

  return g_list_reverse (list);

}

/* Stolen from libtracker-sparql */

static gchar *

sparql_escape_string (const gchar *literal)

{

  GString *str;

  const gchar *p;

  g_return_val_if_fail (literal != NULL, NULL);

  str = g_string_new ("");

  p = literal;

  while (TRUE)

     {

      gsize len;

      if (!((*p) != '\0'))

        break;

      len = strcspn ((const gchar *) p, "\t\n\r\b\f\"\\");

      g_string_append_len (str, (const gchar *) p, (gssize) ((glong) len));

      p = p + len;

      switch (*p)

        {

        case '\t':

          g_string_append (str, "\\t");

          break;

        case '\n':

          g_string_append (str, "\\n");

          break;

        case '\r':

          g_string_append (str, "\\r");

          break;

        case '\b':

          g_string_append (str, "\\b");

          break;

        case '\f':

          g_string_append (str, "\\f");

          break;

        case '"':

          g_string_append (str, "\\\"");

          break;

        case '\\':

          g_string_append (str, "\\\\");

          break;

        default:

          continue;

        }

      p++;

     }

  return g_string_free (str, FALSE);

 }

static void

sparql_append_string_literal (GString     *sparql,

                              const gchar *str)

{

  gchar *s;

  s = sparql_escape_string (str);

  g_string_append_c (sparql, '"');

  g_string_append (sparql, s);

  g_string_append_c (sparql, '"');

  g_free (s);

}

static void

sparql_append_string_literal_lower_case (GString     *sparql,

                                         const gchar *str)

{

  gchar *s;

  s = g_utf8_strdown (str, -1);

  sparql_append_string_literal (sparql, s);

  g_free (s);

}

static void

query_callback (GObject      *object,

                GAsyncResult *res,

                gpointer      user_data)

{

  GtkSearchEngineTracker *tracker;

  GList *hits;

  GVariant *reply;

  GVariant *r;

  GVariantIter iter;

  gchar **result;

  GError *error = NULL;

  gint i, n;

  gdk_threads_enter ();

  tracker = GTK_SEARCH_ENGINE_TRACKER (user_data);

  tracker->priv->query_pending = FALSE;

  reply = g_dbus_connection_call_finish (tracker->priv->connection, res, &error);

  if (error)

    {

      _gtk_search_engine_error (GTK_SEARCH_ENGINE (tracker), error->message);

      g_error_free (error);

      gdk_threads_leave ();

      return;

    }

  if (!reply)

    {

      _gtk_search_engine_finished (GTK_SEARCH_ENGINE (tracker));

      gdk_threads_leave ();

      return;

    }

  r = g_variant_get_child_value (reply, 0);

  g_variant_iter_init (&iter, r);

  n = g_variant_iter_n_children (&iter);

  result = g_new0 (gchar *, n + 1);

  for (i = 0; i < n; i++)

    {

      GVariant *v;

      const gchar **strv;

      v = g_variant_iter_next_value (&iter);

      strv = g_variant_get_strv (v, NULL);

      result[i] = (gchar*)strv[0];

      g_free (strv);

    }

  /* We iterate result by result, not n at a time. */

  hits = string_list_to_gslist (result);

  _gtk_search_engine_hits_added (GTK_SEARCH_ENGINE (tracker), hits);

  _gtk_search_engine_finished (GTK_SEARCH_ENGINE (tracker));

  g_list_free (hits);

  g_free (result);

  g_variant_unref (reply);

  g_variant_unref (r);

  gdk_threads_leave ();

}

static void

gtk_search_engine_tracker_start (GtkSearchEngine *engine)

{

  GtkSearchEngineTracker *tracker;

  gchar *search_text;

#ifdef FTS_MATCHING

  gchar *location_uri;

#endif

  GString *sparql;

  tracker = GTK_SEARCH_ENGINE_TRACKER (engine);

  if (tracker->priv->query_pending)

    {

      g_debug ("Attempt to start a new search while one is pending, doing nothing");

      return;

    }

  if (tracker->priv->query == NULL)

    {

      g_debug ("Attempt to start a new search with no GtkQuery, doing nothing");

      return;

    }

  search_text = _gtk_query_get_text (tracker->priv->query);

#ifdef FTS_MATCHING

  location_uri = _gtk_query_get_location (tracker->priv->query);

  /* Using FTS: */

  sparql = g_string_new ("SELECT nie:url(?urn) "

                         "WHERE {"

                         "  ?urn a nfo:FileDataObject ;"

                         "  tracker:available true ; "

                         "  fts:match ");

  sparql_append_string_literal (sparql, search_text);

  if (location_uri)

    {

      g_string_append (sparql, " . FILTER (fn:starts-with(nie:url(?urn),");

      sparql_append_string_literal (sparql, location_uri);

      g_string_append (sparql, "))");

    }

  g_string_append (sparql, " } ORDER BY DESC(fts:rank(?urn)) ASC(nie:url(?urn))");

#else  /* FTS_MATCHING */

  /* Using filename matching: */

  sparql = g_string_new ("SELECT nie:url(?urn) "

                         "WHERE {"

                         "  ?urn a nfo:FileDataObject ;"

                         "    tracker:available true ."

                         "  FILTER (fn:contains(fn:lower-case(nfo:fileName(?urn)),");

  sparql_append_string_literal_lower_case (sparql, search_text);

  g_string_append (sparql,

                   "))"

                   "} ORDER BY DESC(nie:url(?urn)) DESC(nfo:fileName(?urn))");

#endif /* FTS_MATCHING */

  tracker->priv->query_pending = TRUE;

  get_query_results (tracker, sparql->str, query_callback, tracker);

  g_string_free (sparql, TRUE);

  g_free (search_text);

}

static void

gtk_search_engine_tracker_stop (GtkSearchEngine *engine)

{

  GtkSearchEngineTracker *tracker;

  tracker = GTK_SEARCH_ENGINE_TRACKER (engine);

  if (tracker->priv->query && tracker->priv->query_pending)

    {

      g_cancellable_cancel (tracker->priv->cancellable);

      tracker->priv->query_pending = FALSE;

    }

}

static gboolean

gtk_search_engine_tracker_is_indexed (GtkSearchEngine *engine)

{

  return TRUE;

}

static void

gtk_search_engine_tracker_set_query (GtkSearchEngine *engine,

                                     GtkQuery        *query)

{

  GtkSearchEngineTracker *tracker;

  tracker = GTK_SEARCH_ENGINE_TRACKER (engine);

  if (query)

    g_object_ref (query);

  if (tracker->priv->query)

    g_object_unref (tracker->priv->query);

  tracker->priv->query = query;

}

static void

_gtk_search_engine_tracker_class_init (GtkSearchEngineTrackerClass *class)

{

  GObjectClass *gobject_class;

  GtkSearchEngineClass *engine_class;

  gobject_class = G_OBJECT_CLASS (class);

  gobject_class->finalize = finalize;

  engine_class = GTK_SEARCH_ENGINE_CLASS (class);

  engine_class->set_query = gtk_search_engine_tracker_set_query;

  engine_class->start = gtk_search_engine_tracker_start;

  engine_class->stop = gtk_search_engine_tracker_stop;

  engine_class->is_indexed = gtk_search_engine_tracker_is_indexed;

  g_type_class_add_private (gobject_class,

                            sizeof (GtkSearchEngineTrackerPrivate));

}

static void

_gtk_search_engine_tracker_init (GtkSearchEngineTracker *engine)

{

  engine->priv = G_TYPE_INSTANCE_GET_PRIVATE (engine,

                                              GTK_TYPE_SEARCH_ENGINE_TRACKER,

                                              GtkSearchEngineTrackerPrivate);

}

GtkSearchEngine *

_gtk_search_engine_tracker_new (void)

{

  GtkSearchEngineTracker *engine;

  GDBusConnection *connection;

  g_debug ("--");

  connection = get_connection ();

  if (!connection)

    return NULL;

  g_debug ("Creating GtkSearchEngineTracker...");

  engine = g_object_new (GTK_TYPE_SEARCH_ENGINE_TRACKER, NULL);

  engine->priv->connection = connection;

  engine->priv->cancellable = g_cancellable_new ();

  engine->priv->query_pending = FALSE;

  return GTK_SEARCH_ENGINE (engine);

}