/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*- */
/*
 * Copyright (C) 2001-2003 CodeFactory AB
 * Copyright (C) 2001-2003 Mikael Hallendal <micke@imendio.com>
 * Copyright (C) 2005-2008 Imendio AB
 * Copyright (C) 2010 Lanedo GmbH
 * Copyright (C) 2013 Aleksander Morgado <aleksander@gnu.org>
 * Copyright (C) 2015, 2017, 2018 Sébastien Wilmet <swilmet@gnome.org>
 *
 * This program 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 2 of the
 * License, or (at your option) any later version.
 *
 * This program 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 this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include "dh-sidebar.h"
#include "dh-book.h"
#include "dh-book-tree.h"
#include "dh-keyword-model.h"

/**
 * SECTION:dh-sidebar
 * @Title: DhSidebar
 * @Short_description: The sidebar
 *
 * In the Devhelp application, there is one #DhSidebar per main window,
 * displayed in the left side panel.
 *
 * A #DhSidebar contains:
 * - a #GtkSearchEntry at the top;
 * - a #DhBookTree (a subclass of #GtkTreeView);
 * - another #GtkTreeView (displaying a list, not a tree) with a #DhKeywordModel
 *   as its model.
 *
 * When the #GtkSearchEntry is empty, the #DhBookTree is shown. When the
 * #GtkSearchEntry is not empty, it shows the search results in the other
 * #GtkTreeView. The two #GtkTreeView's cannot be both visible at the same time,
 * it's either one or the other.
 *
 * The #DhSidebar::link-selected signal is emitted when one element in one of
 * the #GtkTreeView's is selected. When that happens, the Devhelp application
 * opens the link in a #WebKitWebView shown at the right side of the main
 * window.
 */

typedef struct {
        /* A GtkSearchEntry. */
        GtkEntry *entry;

        DhBookTree *book_tree;
        GtkScrolledWindow *sw_book_tree;

        DhKeywordModel *hitlist_model;
        GtkTreeView *hitlist_view;
        GtkScrolledWindow *sw_hitlist;

        guint idle_complete_id;
        guint idle_search_id;
} DhSidebarPrivate;

enum {
        SIGNAL_LINK_SELECTED,
        N_SIGNALS
};

static guint signals[N_SIGNALS] = { 0 };

G_DEFINE_TYPE_WITH_PRIVATE (DhSidebar, dh_sidebar, GTK_TYPE_GRID)

static void
dh_sidebar_dispose (GObject *object)
{
        DhSidebarPrivate *priv = dh_sidebar_get_instance_private (DH_SIDEBAR (object));

        g_clear_object (&priv->hitlist_model);

        if (priv->idle_complete_id != 0) {
                g_source_remove (priv->idle_complete_id);
                priv->idle_complete_id = 0;
        }

        if (priv->idle_search_id != 0) {
                g_source_remove (priv->idle_search_id);
                priv->idle_search_id = 0;
        }

        G_OBJECT_CLASS (dh_sidebar_parent_class)->dispose (object);
}

static void
dh_sidebar_class_init (DhSidebarClass *klass)
{
        GObjectClass *object_class = G_OBJECT_CLASS (klass);

        object_class->dispose = dh_sidebar_dispose;

        /**
         * DhSidebar::link-selected:
         * @sidebar: a #DhSidebar.
         * @link: the selected #DhLink.
         */
        signals[SIGNAL_LINK_SELECTED] =
                g_signal_new ("link-selected",
                              G_TYPE_FROM_CLASS (klass),
                              G_SIGNAL_RUN_LAST,
                              G_STRUCT_OFFSET (DhSidebarClass, link_selected),
                              NULL, NULL, NULL,
                              G_TYPE_NONE,
                              1, DH_TYPE_LINK);
}

/******************************************************************************/

static gboolean
search_idle_cb (gpointer user_data)
{
        DhSidebar *sidebar = DH_SIDEBAR (user_data);
        DhSidebarPrivate *priv = dh_sidebar_get_instance_private (sidebar);
        const gchar *search_text;
        const gchar *book_id;
        DhLink *book_link;
        DhLink *exact_link;

        priv->idle_search_id = 0;

        search_text = gtk_entry_get_text (priv->entry);

        book_link = dh_book_tree_get_selected_book (priv->book_tree);
        book_id = book_link != NULL ? dh_link_get_book_id (book_link) : NULL;

        /* Disconnect the model, see the doc of dh_keyword_model_filter(). */
        gtk_tree_view_set_model (priv->hitlist_view, NULL);

        exact_link = dh_keyword_model_filter (priv->hitlist_model,
                                              search_text,
                                              book_id,
                                              NULL);

        gtk_tree_view_set_model (priv->hitlist_view,
                                 GTK_TREE_MODEL (priv->hitlist_model));

        if (exact_link != NULL)
                g_signal_emit (sidebar, signals[SIGNAL_LINK_SELECTED], 0, exact_link);

        if (book_link != NULL)
                dh_link_unref (book_link);

        return G_SOURCE_REMOVE;
}

static void
setup_search_idle (DhSidebar *sidebar)
{
        DhSidebarPrivate *priv = dh_sidebar_get_instance_private (sidebar);

        if (priv->idle_search_id == 0)
                priv->idle_search_id = g_idle_add (search_idle_cb, sidebar);
}

static void
book_manager_changed_cb (DhSidebar *sidebar)
{
        /* Update current search if any. */
        setup_search_idle (sidebar);
}

/******************************************************************************/

static void
hitlist_selection_changed_cb (GtkTreeSelection *selection,
                              DhSidebar        *sidebar)
{
        DhSidebarPrivate *priv = dh_sidebar_get_instance_private (sidebar);
        GtkTreeIter iter;

        if (gtk_tree_selection_get_selected (selection, NULL, &iter)) {
                DhLink *link;

                gtk_tree_model_get (GTK_TREE_MODEL (priv->hitlist_model), &iter,
                                    DH_KEYWORD_MODEL_COL_LINK, &link,
                                    -1);

                g_signal_emit (sidebar, signals[SIGNAL_LINK_SELECTED], 0, link);
                dh_link_unref (link);
        }
}

/* Make it possible to jump back to the currently selected item, useful when the
 * html view has been scrolled away.
 */
static gboolean
hitlist_button_press_cb (GtkTreeView    *hitlist_view,
                         GdkEventButton *event,
                         DhSidebar      *sidebar)
{
        DhSidebarPrivate *priv = dh_sidebar_get_instance_private (sidebar);
        GtkTreePath *path;
        GtkTreeIter iter;
        DhLink *link;

        gtk_tree_view_get_path_at_pos (hitlist_view, event->x, event->y, &path,
                                       NULL, NULL, NULL);
        if (path == NULL)
                return GDK_EVENT_PROPAGATE;

        gtk_tree_model_get_iter (GTK_TREE_MODEL (priv->hitlist_model), &iter, path);
        gtk_tree_path_free (path);

        gtk_tree_model_get (GTK_TREE_MODEL (priv->hitlist_model),
                            &iter,
                            DH_KEYWORD_MODEL_COL_LINK, &link,
                            -1);

        g_signal_emit (sidebar, signals[SIGNAL_LINK_SELECTED], 0, link);
        dh_link_unref (link);

        /* Always propagate the event so the tree view can update
         * the selection etc.
         */
        return GDK_EVENT_PROPAGATE;
}

static gboolean
entry_key_press_event_cb (GtkEntry    *entry,
                          GdkEventKey *event,
                          DhSidebar   *sidebar)
{
        DhSidebarPrivate *priv = dh_sidebar_get_instance_private (sidebar);

        if (event->keyval == GDK_KEY_Tab) {
                if (event->state & GDK_CONTROL_MASK) {
                        if (gtk_widget_is_visible (GTK_WIDGET (priv->hitlist_view)))
                                gtk_widget_grab_focus (GTK_WIDGET (priv->hitlist_view));
                } else {
                        gtk_editable_select_region (GTK_EDITABLE (entry), 0, 0);
                        gtk_editable_set_position (GTK_EDITABLE (entry), -1);
                }

                return GDK_EVENT_STOP;
        }

        if (event->keyval == GDK_KEY_Return ||
            event->keyval == GDK_KEY_KP_Enter) {
                GtkTreeIter iter;
                DhLink *link;
                gchar *name;

                /* Get the first entry found.
                 *
                 * FIXME: is it really useful to do that? If there is an exact
                 * match it already gets selected, so it seems that the feature
                 * here just selects a random symbol (the one that appears to be
                 * the first in the list).
                 * I've never used this feature -- swilmet.
                 * This has been implemented in
                 * commit 455440a93d1b55d5a1e53ecabb2ee33093eec965
                 * and https://bugzilla.gnome.org/show_bug.cgi?id=114558
                 * but maybe at that time the search didn't jump to the exact
                 * match if there was one.
                 */
                if (gtk_widget_is_visible (GTK_WIDGET (priv->hitlist_view)) &&
                    gtk_tree_model_get_iter_first (GTK_TREE_MODEL (priv->hitlist_model), &iter)) {
                        gtk_tree_model_get (GTK_TREE_MODEL (priv->hitlist_model),
                                            &iter,
                                            DH_KEYWORD_MODEL_COL_LINK, &link,
                                            DH_KEYWORD_MODEL_COL_NAME, &name,
                                            -1);

                        gtk_entry_set_text (entry, name);
                        g_free (name);

                        gtk_editable_select_region (GTK_EDITABLE (entry), 0, 0);
                        gtk_editable_set_position (GTK_EDITABLE (entry), -1);

                        g_signal_emit (sidebar, signals[SIGNAL_LINK_SELECTED], 0, link);
                        dh_link_unref (link);

                        return GDK_EVENT_STOP;
                }
        }

        return GDK_EVENT_PROPAGATE;
}

static void
entry_changed_cb (GtkEntry  *entry,
                  DhSidebar *sidebar)
{
        DhSidebarPrivate *priv = dh_sidebar_get_instance_private (sidebar);
        const gchar *search_text;

        search_text = gtk_entry_get_text (entry);

        /* We don't want a delay when the search text becomes empty, to show the
         * book tree. So do it here and not in entry_search_changed_cb().
         */
        if (search_text == NULL || search_text[0] == '\0') {
                gtk_widget_hide (GTK_WIDGET (priv->sw_hitlist));
                gtk_widget_show (GTK_WIDGET (priv->sw_book_tree));
        }
}

static void
entry_search_changed_cb (GtkSearchEntry *search_entry,
                         DhSidebar      *sidebar)
{
        DhSidebarPrivate *priv = dh_sidebar_get_instance_private (sidebar);
        const gchar *search_text;

        search_text = gtk_entry_get_text (GTK_ENTRY (search_entry));

        if (search_text != NULL && search_text[0] != '\0') {
                gtk_widget_hide (GTK_WIDGET (priv->sw_book_tree));
                gtk_widget_show (GTK_WIDGET (priv->sw_hitlist));
                setup_search_idle (sidebar);
        }
}

static gboolean
complete_idle_cb (gpointer user_data)
{
        DhSidebar *sidebar = DH_SIDEBAR (user_data);
        DhSidebarPrivate *priv = dh_sidebar_get_instance_private (sidebar);
        DhBookManager *book_manager;
        GList *books;
        GList *l;
        GList *completion_objects = NULL;
        const gchar *search_text;
        gchar *completed;

        book_manager = dh_book_manager_get_singleton ();
        books = dh_book_manager_get_books (book_manager);
        for (l = books; l != NULL; l = l->next) {
                DhBook *cur_book = DH_BOOK (l->data);

                if (dh_book_get_enabled (cur_book)) {
                        DhCompletion *completion;

                        completion = dh_book_get_completion (cur_book);
                        completion_objects = g_list_prepend (completion_objects, completion);
                }
        }

        search_text = gtk_entry_get_text (priv->entry);
        completed = dh_completion_aggregate_complete (completion_objects, search_text);

        if (completed != NULL) {
                guint16 n_chars_before;

                n_chars_before = gtk_entry_get_text_length (priv->entry);

                gtk_entry_set_text (priv->entry, completed);
                gtk_editable_set_position (GTK_EDITABLE (priv->entry), n_chars_before);
                gtk_editable_select_region (GTK_EDITABLE (priv->entry),
                                            n_chars_before, -1);
        }

        g_list_free (completion_objects);
        g_free (completed);

        priv->idle_complete_id = 0;
        return G_SOURCE_REMOVE;
}

static void
entry_insert_text_cb (GtkEntry    *entry,
                      const gchar *text,
                      gint         length,
                      gint        *position,
                      DhSidebar   *sidebar)
{
        DhSidebarPrivate *priv = dh_sidebar_get_instance_private (sidebar);

        if (priv->idle_complete_id == 0)
                priv->idle_complete_id = g_idle_add (complete_idle_cb, sidebar);
}

static void
entry_stop_search_cb (GtkSearchEntry *entry,
                      gpointer        user_data)
{
        gtk_entry_set_text (GTK_ENTRY (entry), "");
}

static void
hitlist_cell_data_func (GtkTreeViewColumn *tree_column,
                        GtkCellRenderer   *cell,
                        GtkTreeModel      *hitlist_model,
                        GtkTreeIter       *iter,
                        gpointer           data)
{
        DhLink *link;
        DhLinkType link_type;
        PangoStyle style;
        PangoWeight weight;
        gboolean current_book_flag;
        gchar *name;

        gtk_tree_model_get (hitlist_model, iter,
                            DH_KEYWORD_MODEL_COL_LINK, &link,
                            DH_KEYWORD_MODEL_COL_CURRENT_BOOK_FLAG, &current_book_flag,
                            -1);

        if (dh_link_get_flags (link) & DH_LINK_FLAGS_DEPRECATED)
                style = PANGO_STYLE_ITALIC;
        else
                style = PANGO_STYLE_NORMAL;

        /* Matches on the current book are given in bold. Note that we check the
         * current book as it was given to the DhKeywordModel. Do *not* rely on
         * the current book as given by the DhSidebar, as that will change
         * whenever a hit is clicked.
         */
        if (current_book_flag)
                weight = PANGO_WEIGHT_BOLD;
        else
                weight = PANGO_WEIGHT_NORMAL;

        link_type = dh_link_get_link_type (link);

        if (link_type == DH_LINK_TYPE_STRUCT ||
            link_type == DH_LINK_TYPE_PROPERTY ||
            link_type == DH_LINK_TYPE_SIGNAL) {
                name = g_markup_printf_escaped ("%s <i><small><span weight=\"normal\">(%s)</span></small></i>",
                                                dh_link_get_name (link),
                                                dh_link_type_to_string (link_type));
        } else {
                name = g_markup_printf_escaped ("%s", dh_link_get_name (link));
        }

        g_object_set (cell,
                      "markup", name,
                      "style", style,
                      "weight", weight,
                      NULL);

        dh_link_unref (link);
        g_free (name);
}

static void
book_tree_link_selected_cb (DhBookTree *book_tree,
                            DhLink     *link,
                            DhSidebar  *sidebar)
{
        g_signal_emit (sidebar, signals[SIGNAL_LINK_SELECTED], 0, link);
}

static void
dh_sidebar_init (DhSidebar *sidebar)
{
        DhSidebarPrivate *priv = dh_sidebar_get_instance_private (sidebar);
        GtkCellRenderer *cell;
        DhBookManager *book_manager;

        gtk_orientable_set_orientation (GTK_ORIENTABLE (sidebar),
                                        GTK_ORIENTATION_VERTICAL);

        gtk_widget_set_hexpand (GTK_WIDGET (sidebar), TRUE);
        gtk_widget_set_vexpand (GTK_WIDGET (sidebar), TRUE);

        /* Setup the search entry */
        priv->entry = GTK_ENTRY (gtk_search_entry_new ());
        gtk_widget_set_hexpand (GTK_WIDGET (priv->entry), TRUE);
        g_object_set (priv->entry,
                      "margin", 6,
                      NULL);
        gtk_container_add (GTK_CONTAINER (sidebar), GTK_WIDGET (priv->entry));

        g_signal_connect (priv->entry,
                          "key-press-event",
                          G_CALLBACK (entry_key_press_event_cb),
                          sidebar);

        g_signal_connect (priv->entry,
                          "changed",
                          G_CALLBACK (entry_changed_cb),
                          sidebar);

        g_signal_connect (priv->entry,
                          "search-changed",
                          G_CALLBACK (entry_search_changed_cb),
                          sidebar);

        g_signal_connect (priv->entry,
                          "insert-text",
                          G_CALLBACK (entry_insert_text_cb),
                          sidebar);

        g_signal_connect (priv->entry,
                          "stop-search",
                          G_CALLBACK (entry_stop_search_cb),
                          NULL);

        /* Setup hitlist */
        priv->hitlist_model = dh_keyword_model_new ();
        priv->hitlist_view = GTK_TREE_VIEW (gtk_tree_view_new ());
        gtk_tree_view_set_model (priv->hitlist_view, GTK_TREE_MODEL (priv->hitlist_model));
        gtk_tree_view_set_headers_visible (priv->hitlist_view, FALSE);
        gtk_tree_view_set_enable_search (priv->hitlist_view, FALSE);
        gtk_widget_show (GTK_WIDGET (priv->hitlist_view));

        g_signal_connect (priv->hitlist_view,
                          "button-press-event",
                          G_CALLBACK (hitlist_button_press_cb),
                          sidebar);

        g_signal_connect (gtk_tree_view_get_selection (priv->hitlist_view),
                          "changed",
                          G_CALLBACK (hitlist_selection_changed_cb),
                          sidebar);

        cell = gtk_cell_renderer_text_new ();
        g_object_set (cell,
                      "ellipsize", PANGO_ELLIPSIZE_END,
                      NULL);
        gtk_tree_view_insert_column_with_data_func (priv->hitlist_view,
                                                    -1,
                                                    NULL,
                                                    cell,
                                                    hitlist_cell_data_func,
                                                    sidebar,
                                                    NULL);

        /* Hitlist packing */
        priv->sw_hitlist = GTK_SCROLLED_WINDOW (gtk_scrolled_window_new (NULL, NULL));
        gtk_widget_set_no_show_all (GTK_WIDGET (priv->sw_hitlist), TRUE);
        gtk_scrolled_window_set_policy (priv->sw_hitlist,
                                        GTK_POLICY_NEVER,
                                        GTK_POLICY_AUTOMATIC);
        gtk_container_add (GTK_CONTAINER (priv->sw_hitlist),
                           GTK_WIDGET (priv->hitlist_view));
        gtk_widget_set_hexpand (GTK_WIDGET (priv->sw_hitlist), TRUE);
        gtk_widget_set_vexpand (GTK_WIDGET (priv->sw_hitlist), TRUE);
        gtk_container_add (GTK_CONTAINER (sidebar), GTK_WIDGET (priv->sw_hitlist));

        /* Setup book manager */
        book_manager = dh_book_manager_get_singleton ();

        g_signal_connect_object (book_manager,
                                 "book-created",
                                 G_CALLBACK (book_manager_changed_cb),
                                 sidebar,
                                 G_CONNECT_SWAPPED);

        g_signal_connect_object (book_manager,
                                 "book-enabled",
                                 G_CALLBACK (book_manager_changed_cb),
                                 sidebar,
                                 G_CONNECT_SWAPPED);

        g_signal_connect_object (book_manager,
                                 "book-deleted",
                                 G_CALLBACK (book_manager_changed_cb),
                                 sidebar,
                                 G_CONNECT_SWAPPED);

        g_signal_connect_object (book_manager,
                                 "book-disabled",
                                 G_CALLBACK (book_manager_changed_cb),
                                 sidebar,
                                 G_CONNECT_SWAPPED);

        /* Setup the book tree */
        priv->sw_book_tree = GTK_SCROLLED_WINDOW (gtk_scrolled_window_new (NULL, NULL));
        gtk_widget_show (GTK_WIDGET (priv->sw_book_tree));
        gtk_widget_set_no_show_all (GTK_WIDGET (priv->sw_book_tree), TRUE);
        gtk_scrolled_window_set_policy (priv->sw_book_tree,
                                        GTK_POLICY_NEVER,
                                        GTK_POLICY_AUTOMATIC);

        priv->book_tree = dh_book_tree_new ();
        gtk_widget_show (GTK_WIDGET (priv->book_tree));
        g_signal_connect (priv->book_tree,
                          "link-selected",
                          G_CALLBACK (book_tree_link_selected_cb),
                          sidebar);
        gtk_container_add (GTK_CONTAINER (priv->sw_book_tree), GTK_WIDGET (priv->book_tree));
        gtk_widget_set_hexpand (GTK_WIDGET (priv->sw_book_tree), TRUE);
        gtk_widget_set_vexpand (GTK_WIDGET (priv->sw_book_tree), TRUE);
        gtk_container_add (GTK_CONTAINER (sidebar), GTK_WIDGET (priv->sw_book_tree));

        gtk_widget_show_all (GTK_WIDGET (sidebar));
}

/**
 * dh_sidebar_new:
 * @book_manager: (nullable): a #DhBookManager. This parameter is deprecated,
 * you should just pass %NULL.
 *
 * Returns: (transfer floating): a new #DhSidebar widget.
 */
GtkWidget *
dh_sidebar_new (DhBookManager *book_manager)
{
        return g_object_new (DH_TYPE_SIDEBAR, NULL);
}

/**
 * dh_sidebar_select_uri:
 * @sidebar: a #DhSidebar.
 * @uri: the URI to select.
 */
void
dh_sidebar_select_uri (DhSidebar   *sidebar,
                       const gchar *uri)
{
        DhSidebarPrivate *priv;

        g_return_if_fail (DH_IS_SIDEBAR (sidebar));
        g_return_if_fail (uri != NULL);

        priv = dh_sidebar_get_instance_private (sidebar);

        dh_book_tree_select_uri (priv->book_tree, uri);
}

/**
 * dh_sidebar_set_search_string:
 * @sidebar: a #DhSidebar.
 * @str: the string to search.
 */
void
dh_sidebar_set_search_string (DhSidebar   *sidebar,
                              const gchar *str)
{
        DhSidebarPrivate *priv;

        g_return_if_fail (DH_IS_SIDEBAR (sidebar));
        g_return_if_fail (str != NULL);

        priv = dh_sidebar_get_instance_private (sidebar);

        gtk_entry_set_text (priv->entry, str);
        gtk_editable_select_region (GTK_EDITABLE (priv->entry), 0, 0);
        gtk_editable_set_position (GTK_EDITABLE (priv->entry), -1);

        /* If the GtkEntry text was already equal to @str, the
         * GtkEditable::changed signal was not emitted, so force to emit it to
         * call entry_changed_cb() and entry_search_changed_cb(), forcing a new
         * search. If an exact match is found, the DhSidebar::link-selected
         * signal will be emitted, to re-jump to that symbol (even if the
         * GtkEntry text was equal, it doesn't mean that the WebKitWebView was
         * showing the exact match).
         * https://bugzilla.gnome.org/show_bug.cgi?id=776596
         */
        g_signal_emit_by_name (priv->entry, "changed");
}

/**
 * dh_sidebar_set_search_focus:
 * @sidebar: a #DhSidebar.
 *
 * Gives the focus to the search entry.
 */
void
dh_sidebar_set_search_focus (DhSidebar *sidebar)
{
        DhSidebarPrivate *priv;

        g_return_if_fail (DH_IS_SIDEBAR (sidebar));

        priv = dh_sidebar_get_instance_private (sidebar);

        gtk_widget_grab_focus (GTK_WIDGET (priv->entry));
}