/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/*
 *  Copyright © 2012 Igalia S.L.
 *
 *  This file is part of Epiphany.
 *
 *  Epiphany is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  Epiphany 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Epiphany.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"
#include "ephy-completion-model.h"

#include "ephy-embed-prefs.h"
#include "ephy-embed-shell.h"
#include "ephy-favicon-helpers.h"
#include "ephy-history-service.h"
#include "ephy-shell.h"
#include "ephy-uri-helpers.h"

#include <string.h>

enum {
  PROP_0,
  PROP_HISTORY_SERVICE,
  PROP_BOOKMARKS_MANAGER,
  LAST_PROP
};

struct _EphyCompletionModel {
  GtkListStore parent_instance;

  EphyHistoryService *history_service;
  GCancellable *cancellable;

  EphyBookmarksManager *bookmarks_manager;
  GSList *search_terms;
};

static GParamSpec *obj_properties[LAST_PROP];

G_DEFINE_TYPE (EphyCompletionModel, ephy_completion_model, GTK_TYPE_LIST_STORE)

static void
ephy_completion_model_constructed (GObject *object)
{
  GType types[N_COL] = { G_TYPE_STRING, G_TYPE_STRING, G_TYPE_STRING,
                         G_TYPE_INT, G_TYPE_STRING, G_TYPE_BOOLEAN,
                         GDK_TYPE_PIXBUF };

  G_OBJECT_CLASS (ephy_completion_model_parent_class)->constructed (object);

  gtk_list_store_set_column_types (GTK_LIST_STORE (object),
                                   N_COL,
                                   types);
}

static void
free_search_terms (GSList *search_terms)
{
  GSList *iter;

  for (iter = search_terms; iter != NULL; iter = iter->next)
    g_regex_unref ((GRegex *)iter->data);

  g_slist_free (search_terms);
}

static void
ephy_completion_model_set_property (GObject *object, guint property_id, const GValue *value, GParamSpec *pspec)
{
  EphyCompletionModel *self = EPHY_COMPLETION_MODEL (object);

  switch (property_id) {
    case PROP_HISTORY_SERVICE:
      self->history_service = EPHY_HISTORY_SERVICE (g_value_get_pointer (value));
      break;
    case PROP_BOOKMARKS_MANAGER:
      self->bookmarks_manager = EPHY_BOOKMARKS_MANAGER (g_value_get_object (value));
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (self, property_id, pspec);
      break;
  }
}

static void
ephy_completion_model_finalize (GObject *object)
{
  EphyCompletionModel *model = EPHY_COMPLETION_MODEL (object);

  if (model->search_terms) {
    free_search_terms (model->search_terms);
    model->search_terms = NULL;
  }

  if (model->cancellable) {
    g_cancellable_cancel (model->cancellable);
    g_clear_object (&model->cancellable);
  }

  G_OBJECT_CLASS (ephy_completion_model_parent_class)->finalize (object);
}

static void
ephy_completion_model_class_init (EphyCompletionModelClass *klass)
{
  GObjectClass *object_class = G_OBJECT_CLASS (klass);

  object_class->set_property = ephy_completion_model_set_property;
  object_class->constructed = ephy_completion_model_constructed;
  object_class->finalize = ephy_completion_model_finalize;

  obj_properties[PROP_HISTORY_SERVICE] =
    g_param_spec_pointer ("history-service",
                          "History Service",
                          "The history service",
                          G_PARAM_CONSTRUCT_ONLY | G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS);

  obj_properties[PROP_BOOKMARKS_MANAGER] =
    g_param_spec_object ("bookmarks-manager",
                         "Bookmarks manager",
                         "The bookmarks manager",
                         EPHY_TYPE_BOOKMARKS_MANAGER,
                         G_PARAM_CONSTRUCT_ONLY | G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS);

  g_object_class_install_properties (object_class, LAST_PROP, obj_properties);
}

static void
ephy_completion_model_init (EphyCompletionModel *model)
{
}

static gboolean
is_base_address (const char *address)
{
  if (address == NULL)
    return FALSE;

  /* A base address is <scheme>://<host>/
   * Neither scheme nor host contain a slash, so we can use slashes
   * figure out if it's a base address.
   *
   * Note: previous code was using a GRegExp to do the same thing.
   * While regexps are much nicer to read, they're also a lot
   * slower.
   */
  address = strchr (address, '/');
  if (address == NULL ||
      address[1] != '/')
    return FALSE;

  address += 2;
  address = strchr (address, '/');
  if (address == NULL ||
      address[1] != 0)
    return FALSE;

  return TRUE;
}

static int
get_relevance (const char *location,
               int         visit_count,
               gboolean    is_bookmark)
{
  /* FIXME: use frecency. */
  int relevance = 0;

  /* We have three ordered groups: history's base addresses,
     bookmarks, deep history addresses. */
  if (is_bookmark)
    relevance = 1 << 5;
  else {
    visit_count = MIN (visit_count, (1 << 5) - 1);

    if (is_base_address (location))
      relevance = visit_count << 10;
    else
      relevance = visit_count;
  }

  return relevance;
}

typedef struct {
  char *title;
  char *location;
  char *keywords;
  int relevance;
  gboolean is_bookmark;
} PotentialRow;

typedef struct {
  GtkListStore *model;
  GtkTreeRowReference *row_reference;
} IconLoadData;

static void
icon_loaded_cb (GObject *source, GAsyncResult *result, gpointer user_data)
{
  GtkTreeIter iter;
  GtkTreePath *path;
  IconLoadData *data = (IconLoadData *)user_data;
  WebKitFaviconDatabase *database = WEBKIT_FAVICON_DATABASE (source);
  GdkPixbuf *favicon = NULL;
  cairo_surface_t *icon_surface = webkit_favicon_database_get_favicon_finish (database, result, NULL);

  if (icon_surface) {
    favicon = ephy_pixbuf_get_from_surface_scaled (icon_surface, FAVICON_SIZE, FAVICON_SIZE);
    cairo_surface_destroy (icon_surface);
  }

  if (favicon) {
    /* The completion model might have changed its contents */
    if (gtk_tree_row_reference_valid (data->row_reference)) {
      path = gtk_tree_row_reference_get_path (data->row_reference);
      gtk_tree_model_get_iter (GTK_TREE_MODEL (data->model), &iter, path);
      gtk_list_store_set (data->model, &iter, EPHY_COMPLETION_FAVICON_COL, favicon, -1);
      g_object_unref (favicon);
      gtk_tree_path_free (path);
    }
  }

  g_object_unref (data->model);
  gtk_tree_row_reference_free (data->row_reference);
  g_slice_free (IconLoadData, data);
}

static void
set_row_in_model (EphyCompletionModel *model, int position, PotentialRow *row)
{
  GtkTreeIter iter;
  GtkTreePath *path;
  IconLoadData *data;
  WebKitFaviconDatabase *database;
  EphyEmbedShell *shell = ephy_embed_shell_get_default ();

  database = webkit_web_context_get_favicon_database (ephy_embed_shell_get_web_context (shell));

  gtk_list_store_insert_with_values (GTK_LIST_STORE (model), &iter, position,
                                     EPHY_COMPLETION_TEXT_COL, row->title ? row->title : "",
                                     EPHY_COMPLETION_URL_COL, row->location,
                                     EPHY_COMPLETION_ACTION_COL, row->location,
                                     EPHY_COMPLETION_KEYWORDS_COL, row->keywords ? row->keywords : "",
                                     EPHY_COMPLETION_EXTRA_COL, row->is_bookmark,
                                     EPHY_COMPLETION_RELEVANCE_COL, row->relevance,
                                     -1);

  data = g_slice_new (IconLoadData);
  data->model = GTK_LIST_STORE (g_object_ref (model));
  path = gtk_tree_model_get_path (GTK_TREE_MODEL (model), &iter);
  data->row_reference = gtk_tree_row_reference_new (GTK_TREE_MODEL (model), path);
  gtk_tree_path_free (path);

  webkit_favicon_database_get_favicon (database, row->location,
                                       NULL, icon_loaded_cb, data);
}

static void
replace_rows_in_model (EphyCompletionModel *model, GSList *new_rows)
{
  /* This is by far the simplest way of doing, and yet it gives
   * basically the same result than the other methods... */
  int i;

  gtk_list_store_clear (GTK_LIST_STORE (model));

  if (!new_rows)
    return;

  for (i = 0; new_rows != NULL; i++) {
    PotentialRow *row = (PotentialRow *)new_rows->data;

    set_row_in_model (model, i, row);
    new_rows = new_rows->next;
  }
}

static gboolean
should_add_bookmark_to_model (EphyCompletionModel *model,
                              const char          *search_string,
                              EphyBookmark        *bookmark)
{
  gboolean ret = TRUE;
  GSequence *tags;
  GSequenceIter *tag_iter;
  const char *url;
  const char *title;
  char *tag_string = NULL;
  char **tag_array;
  int i;

  title = ephy_bookmark_get_title (bookmark);
  url = ephy_bookmark_get_url (bookmark);
  tags = ephy_bookmark_get_tags (bookmark);

  tag_array = g_malloc0 ((g_sequence_get_length (tags) + 1) * sizeof (char *));

  for (i = 0, tag_iter = g_sequence_get_begin_iter (tags);
       !g_sequence_iter_is_end (tag_iter);
       i++, tag_iter = g_sequence_iter_next (tag_iter)) {
    tag_array[i] = g_sequence_get (tag_iter);
  }

  tag_string = g_strjoinv (" ", tag_array);

  if (model->search_terms) {
    GSList *iter;
    GRegex *current = NULL;

    for (iter = model->search_terms; iter != NULL; iter = iter->next) {
      current = (GRegex *)iter->data;

      if ((!g_regex_match (current, title ? title : "", G_REGEX_MATCH_NOTEMPTY, NULL)) &&
          (!g_regex_match (current, url ? url : "", G_REGEX_MATCH_NOTEMPTY, NULL)) &&
          (!g_regex_match (current, tag_string ? tag_string : "", G_REGEX_MATCH_NOTEMPTY, NULL))) {
        ret = FALSE;
        break;
      }
    }
  }

  g_free (tag_array);
  g_free (tag_string);

  return ret;
}

typedef struct {
  EphyCompletionModel *model;
  char *search_string;
  EphyHistoryJobCallback callback;
  gpointer user_data;
} FindURLsData;

static int
find_url (gconstpointer a,
          gconstpointer b)
{
  return g_strcmp0 (((PotentialRow *)a)->location,
                    ((char *)b));
}

static PotentialRow *
potential_row_new (const char *title, const char *location,
                   const char *keywords, int visit_count,
                   gboolean is_bookmark)
{
  PotentialRow *row = g_slice_new0 (PotentialRow);

  row->title = g_strdup (title);
  row->location = g_strdup (location);
  row->keywords = g_strdup (keywords);
  row->relevance = get_relevance (location, visit_count, is_bookmark);
  row->is_bookmark = is_bookmark;

  return row;
}

static void
free_potential_row (PotentialRow *row)
{
  g_free (row->title);
  g_free (row->location);
  g_free (row->keywords);

  g_slice_free (PotentialRow, row);
}

static GSList *
add_to_potential_rows (GSList     *rows,
                       const char *title,
                       const char *location,
                       const char *keywords,
                       int         visit_count,
                       gboolean    is_bookmark,
                       gboolean    search_for_duplicates)
{
  gboolean found = FALSE;
  PotentialRow *row = potential_row_new (title, location, keywords, visit_count, is_bookmark);

  if (search_for_duplicates) {
    GSList *p;

    p = g_slist_find_custom (rows, location, find_url);
    if (p) {
      PotentialRow *match = (PotentialRow *)p->data;
      if (row->relevance > match->relevance)
        match->relevance = row->relevance;

      found = TRUE;
      free_potential_row (row);
    }
  }

  if (!found)
    rows = g_slist_prepend (rows, row);

  return rows;
}

static int
sort_by_relevance (gconstpointer a, gconstpointer b)
{
  PotentialRow *r1 = (PotentialRow *)a;
  PotentialRow *r2 = (PotentialRow *)b;

  if (r1->relevance < r2->relevance)
    return 1;
  else if (r1->relevance > r2->relevance)
    return -1;
  else
    return 0;
}

static void
query_completed_cb (EphyHistoryService *service,
                    gboolean            success,
                    gpointer            result_data,
                    FindURLsData       *user_data)
{
  EphyCompletionModel *model = user_data->model;
  GList *p, *urls;
  GSequence *bookmarks;
  GSequenceIter *iter;
  GSList *list = NULL;

  /* Bookmarks */
  bookmarks = ephy_bookmarks_manager_get_bookmarks (model->bookmarks_manager);

  /* FIXME: perhaps this could be done in a service thread? There
   * should never be a ton of bookmarks, but seems a bit cleaner and
   * consistent with what we do for the history. */
  for (iter = g_sequence_get_begin_iter (bookmarks);
       !g_sequence_iter_is_end (iter);
       iter = g_sequence_iter_next (iter)) {
    EphyBookmark *bookmark;
    const char *url, *title;

    bookmark = g_sequence_get (iter);

    if (should_add_bookmark_to_model (model, user_data->search_string, bookmark)) {
      url = ephy_bookmark_get_url (bookmark);
      title = ephy_bookmark_get_title (bookmark);
      list = add_to_potential_rows (list, title, url, NULL, 0, TRUE, FALSE);
    }
  }

  /* History */
  urls = (GList *)result_data;

  for (p = urls; p != NULL; p = p->next) {
    EphyHistoryURL *url = (EphyHistoryURL *)p->data;

    list = add_to_potential_rows (list, url->title, url->url, NULL, url->visit_count, FALSE, TRUE);
  }

  /* Sort the rows by relevance. */
  list = g_slist_sort (list, sort_by_relevance);

  /* Now that we have all the rows we want to insert, replace the rows
   * in the current model one by one, sorted by relevance. */
  replace_rows_in_model (model, list);

  /* Notify */
  if (user_data->callback)
    user_data->callback (service, success, result_data, user_data->user_data);

  g_free (user_data->search_string);
  g_slice_free (FindURLsData, user_data);
  g_list_free_full (urls, (GDestroyNotify)ephy_history_url_free);
  g_slist_free_full (list, (GDestroyNotify)free_potential_row);
  g_clear_object (&model->cancellable);
}

static void
update_search_terms (EphyCompletionModel *model,
                     const char          *text)
{
  const char *current;
  const char *ptr;
  char *tmp;
  char *term;
  GRegex *term_regex;
  GRegex *quote_regex;
  gint count;
  gboolean inside_quotes = FALSE;

  if (model->search_terms) {
    free_search_terms (model->search_terms);
    model->search_terms = NULL;
  }

  quote_regex = g_regex_new ("\"", G_REGEX_OPTIMIZE,
                             G_REGEX_MATCH_NOTEMPTY, NULL);

  /*
   * This code loops through the string using pointer arythmetics.
   * Although the string we are handling may contain UTF-8 chars
   * this works because only ASCII chars affect what is actually
   * copied from the string as a search term.
   */
  for (count = 0, current = ptr = text; ptr[0] != '\0'; ptr++, count++) {
    /*
     * If we found a double quote character; we will
     * consume bytes up until the next quote, or
     * end of line;
     */
    if (ptr[0] == '"')
      inside_quotes = !inside_quotes;

    /*
     * If we found a space, and we are not looking for a
     * closing double quote, or if the next char is the
     * end of the string, append what we have already as
     * a search term.
     */
    if (((ptr[0] == ' ') && (!inside_quotes)) || ptr[1] == '\0') {
      /*
       * We special-case the end of the line because
       * we would otherwise not copy the last character
       * of the search string, since the for loop will
       * stop before that.
       */
      if (ptr[1] == '\0')
        count++;

      /*
       * remove quotes, and quote any regex-sensitive
       * characters
       */
      tmp = g_regex_escape_string (current, count);
      term = g_regex_replace (quote_regex, tmp, -1, 0,
                              "", G_REGEX_MATCH_NOTEMPTY, NULL);
      g_strstrip (term);
      g_free (tmp);

      /* we don't want empty search terms */
      if (term[0] != '\0') {
        term_regex = g_regex_new (term,
                                  G_REGEX_CASELESS | G_REGEX_OPTIMIZE,
                                  G_REGEX_MATCH_NOTEMPTY, NULL);
        model->search_terms = g_slist_append (model->search_terms, term_regex);
      }
      g_free (term);

      /* count will be incremented by the for loop */
      count = -1;
      current = ptr + 1;
    }
  }

  g_regex_unref (quote_regex);
}

#define MAX_COMPLETION_HISTORY_URLS 8

void
ephy_completion_model_update_for_string (EphyCompletionModel   *model,
                                         const char            *search_string,
                                         EphyHistoryJobCallback callback,
                                         gpointer               data)
{
  char **strings;
  int i;
  GList *query = NULL;
  FindURLsData *user_data;

  g_return_if_fail (EPHY_IS_COMPLETION_MODEL (model));
  g_return_if_fail (search_string != NULL);

  /* Split the search string. */
  strings = g_strsplit (search_string, " ", -1);
  for (i = 0; strings[i]; i++)
    query = g_list_append (query, g_strdup (strings[i]));
  g_strfreev (strings);

  update_search_terms (model, search_string);

  user_data = g_slice_new (FindURLsData);
  user_data->model = model;
  user_data->search_string = g_strdup (search_string);
  user_data->callback = callback;
  user_data->user_data = data;

  if (model->cancellable) {
    g_cancellable_cancel (model->cancellable);
    g_object_unref (model->cancellable);
  }
  model->cancellable = g_cancellable_new ();

  ephy_history_service_find_urls (model->history_service,
                                  0, 0,
                                  MAX_COMPLETION_HISTORY_URLS, 0,
                                  query,
                                  EPHY_HISTORY_SORT_MOST_VISITED,
                                  model->cancellable,
                                  (EphyHistoryJobCallback)query_completed_cb,
                                  user_data);
}

EphyCompletionModel *
ephy_completion_model_new (EphyHistoryService   *history_service,
                           EphyBookmarksManager *bookmarks_manager)
{
  g_return_val_if_fail (EPHY_IS_HISTORY_SERVICE (history_service), NULL);
  g_return_val_if_fail (EPHY_IS_BOOKMARKS_MANAGER (bookmarks_manager), NULL);

  return g_object_new (EPHY_TYPE_COMPLETION_MODEL,
                       "history-service", history_service,
                       "bookmarks-manager", bookmarks_manager,
                       NULL);
}