path: root/calendar/gui/comp-util.c

/*
 * Evolution calendar - Utilities for manipulating ECalComponent objects
 *
 * This program 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) version 3.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with the program; if not, see <http://www.gnu.org/licenses/>
 *
 *
 * Authors:
 *      Federico Mena-Quintero <federico@ximian.com>
 *
 * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <string.h>
#include <time.h>
#include <libedataserverui/libedataserverui.h>

#include "calendar-config.h"
#include "comp-util.h"
#include "dialogs/delete-comp.h"
#include "e-util/e-categories-config.h"

#include "gnome-cal.h"
#include "shell/e-shell-window.h"
#include "shell/e-shell-view.h"

/**
 * cal_comp_util_add_exdate:
 * @comp: A calendar component object.
 * @itt: Time for the exception.
 *
 * Adds an exception date to the current list of EXDATE properties in a calendar
 * component object.
 **/
void
cal_comp_util_add_exdate (ECalComponent *comp,
                          time_t t,
                          icaltimezone *zone)
{
    GSList *list;
    ECalComponentDateTime *cdt;

    g_return_if_fail (comp != NULL);
    g_return_if_fail (E_IS_CAL_COMPONENT (comp));

    e_cal_component_get_exdate_list (comp, &list);

    cdt = g_new (ECalComponentDateTime, 1);
    cdt->value = g_new (struct icaltimetype, 1);
    *cdt->value = icaltime_from_timet_with_zone (t, FALSE, zone);
    cdt->tzid = g_strdup (icaltimezone_get_tzid (zone));

    list = g_slist_append (list, cdt);
    e_cal_component_set_exdate_list (comp, list);
    e_cal_component_free_exdate_list (list);
}

/* Returns TRUE if the TZIDs are equivalent, i.e. both NULL or the same. */
static gboolean
e_cal_component_compare_tzid (const gchar *tzid1,
                              const gchar *tzid2)
{
    gboolean retval = TRUE;

    if (tzid1) {
        if (!tzid2 || strcmp (tzid1, tzid2))
            retval = FALSE;
    } else {
        if (tzid2)
            retval = FALSE;
    }

    return retval;
}

/**
 * cal_comp_util_compare_event_timezones:
 * @comp: A calendar component object.
 * @client: A #ECalClient.
 *
 * Checks if the component uses the given timezone for both the start and
 * the end time, or if the UTC offsets of the start and end times are the same
 * as in the given zone.
 *
 * Returns: TRUE if the component's start and end time are at the same UTC
 * offset in the given timezone.
 **/
gboolean
cal_comp_util_compare_event_timezones (ECalComponent *comp,
                                       ECalClient *client,
                                       icaltimezone *zone)
{
    ECalComponentDateTime start_datetime, end_datetime;
    const gchar *tzid;
    gboolean retval = FALSE;
    icaltimezone *start_zone, *end_zone;
    gint offset1, offset2;

    tzid = icaltimezone_get_tzid (zone);

    e_cal_component_get_dtstart (comp, &start_datetime);
    e_cal_component_get_dtend (comp, &end_datetime);

    /* If either the DTSTART or the DTEND is a DATE value, we return TRUE.
     * Maybe if one was a DATE-TIME we should check that, but that should
     * not happen often. */
    if ((start_datetime.value && start_datetime.value->is_date)
        || (end_datetime.value && end_datetime.value->is_date)) {
        retval = TRUE;
        goto out;
    }

    /* If the event uses UTC for DTSTART & DTEND, return TRUE. Outlook
     * will send single events as UTC, so we don't want to mark all of
     * these. */
    if ((!start_datetime.value || start_datetime.value->is_utc)
        && (!end_datetime.value || end_datetime.value->is_utc)) {
        retval = TRUE;
        goto out;
    }

    /* If the event uses floating time for DTSTART & DTEND, return TRUE.
     * Imported vCalendar files will use floating times, so we don't want
     * to mark all of these. */
    if (!start_datetime.tzid && !end_datetime.tzid) {
        retval = TRUE;
        goto out;
    }

    /* FIXME: DURATION may be used instead. */
    if (e_cal_component_compare_tzid (tzid, start_datetime.tzid)
        && e_cal_component_compare_tzid (tzid, end_datetime.tzid)) {
        /* If both TZIDs are the same as the given zone's TZID, then
         * we know the timezones are the same so we return TRUE. */
        retval = TRUE;
    } else {
        /* If the TZIDs differ, we have to compare the UTC offsets
         * of the start and end times, using their own timezones and
         * the given timezone. */
        if (!e_cal_client_get_timezone_sync (client, start_datetime.tzid,
                          &start_zone, NULL, NULL))
            goto out;

        if (start_datetime.value) {
            offset1 = icaltimezone_get_utc_offset (
                start_zone,
                start_datetime.value,
                NULL);
            offset2 = icaltimezone_get_utc_offset (
                zone,
                start_datetime.value,
                NULL);
            if (offset1 != offset2)
                goto out;
        }

        if (!e_cal_client_get_timezone_sync (client, end_datetime.tzid,
                          &end_zone, NULL, NULL))
            goto out;

        if (end_datetime.value) {
            offset1 = icaltimezone_get_utc_offset (
                end_zone,
                end_datetime.value,
                NULL);
            offset2 = icaltimezone_get_utc_offset (
                zone,
                end_datetime.value,
                NULL);
            if (offset1 != offset2)
                goto out;
        }

        retval = TRUE;
    }

 out:

    e_cal_component_free_datetime (&start_datetime);
    e_cal_component_free_datetime (&end_datetime);

    return retval;
}

/**
 * cal_comp_confirm_delete_empty_comp:
 * @comp: A calendar component.
 * @client: Calendar client where the component purportedly lives.
 * @widget: Widget to be used as the basis for UTF8 conversion.
 *
 * Assumming a calendar component with an empty SUMMARY property (as per
 * string_is_empty()), asks whether the user wants to delete it based on
 * whether the appointment is on the calendar server or not.  If the
 * component is on the server, this function will present a confirmation
 * dialog and delete the component if the user tells it to.  If the component
 * is not on the server it will just return TRUE.
 *
 * Return value: A result code indicating whether the component
 * was not on the server and is to be deleted locally, whether it
 * was on the server and the user deleted it, or whether the
 * user cancelled the deletion.
 **/
gboolean
cal_comp_is_on_server (ECalComponent *comp,
                       ECalClient *client)
{
    const gchar *uid;
    gchar *rid = NULL;
    icalcomponent *icalcomp;
    GError *error = NULL;

    g_return_val_if_fail (comp != NULL, FALSE);
    g_return_val_if_fail (E_IS_CAL_COMPONENT (comp), FALSE);
    g_return_val_if_fail (client != NULL, FALSE);
    g_return_val_if_fail (E_IS_CAL_CLIENT (client), FALSE);

    /* See if the component is on the server.  If it is not, then it likely
     * means that the appointment is new, only in the day view, and we
     * haven't added it yet to the server.  In that case, we don't need to
     * confirm and we can just delete the event.  Otherwise, we ask
     * the user.
     */
    e_cal_component_get_uid (comp, &uid);

    /* TODO We should not be checking for this here. But since
     *      e_cal_util_construct_instance does not create the instances
     *      of all day events, so we default to old behaviour. */
    if (e_cal_client_check_recurrences_no_master (client)) {
        rid = e_cal_component_get_recurid_as_string (comp);
    }

    if (e_cal_client_get_object_sync (client, uid, rid, &icalcomp, NULL, &error)) {
        icalcomponent_free (icalcomp);
        g_free (rid);

        return TRUE;
    }

    if (!g_error_matches (error, E_CAL_CLIENT_ERROR, E_CAL_CLIENT_ERROR_OBJECT_NOT_FOUND))
        g_warning (G_STRLOC ": %s", error->message);

    g_clear_error (&error);
    g_free (rid);

    return FALSE;
}

/**
 * is_icalcomp_on_the_server:
 * same as @cal_comp_is_on_server, only the component parameter is
 * icalcomponent, not the ECalComponent.
 **/
gboolean
is_icalcomp_on_the_server (icalcomponent *icalcomp,
                           ECalClient *client)
{
    gboolean on_server;
    ECalComponent *comp;

    if (!icalcomp || !client || !icalcomponent_get_uid (icalcomp))
        return FALSE;

    comp = e_cal_component_new ();
    e_cal_component_set_icalcomponent (comp, icalcomponent_new_clone (icalcomp));

    on_server = cal_comp_is_on_server (comp, client);

    g_object_unref (comp);

    return on_server;
}

/**
 * cal_comp_event_new_with_defaults:
 *
 * Creates a new VEVENT component and adds any default alarms to it as set in
 * the program's configuration values, but only if not the all_day event.
 *
 * Return value: A newly-created calendar component.
 **/
ECalComponent *
cal_comp_event_new_with_defaults (ECalClient *client,
                                  gboolean all_day,
                                  gboolean use_default_reminder,
                                  gint default_reminder_interval,
                                  EDurationType default_reminder_units)
{
    icalcomponent *icalcomp;
    ECalComponent *comp;
    ECalComponentAlarm *alarm;
    icalproperty *icalprop;
    ECalComponentAlarmTrigger trigger;

    if (!e_cal_client_get_default_object_sync (client, &icalcomp, NULL, NULL))
        icalcomp = icalcomponent_new (ICAL_VEVENT_COMPONENT);

    comp = e_cal_component_new ();
    if (!e_cal_component_set_icalcomponent (comp, icalcomp)) {
        icalcomponent_free (icalcomp);

        e_cal_component_set_new_vtype (comp, E_CAL_COMPONENT_EVENT);
    }

    if (all_day || !use_default_reminder)
        return comp;

    alarm = e_cal_component_alarm_new ();

    /* We don't set the description of the alarm; we'll copy it from the
     * summary when it gets committed to the server. For that, we add a
     * X-EVOLUTION-NEEDS-DESCRIPTION property to the alarm's component.
     */
    icalcomp = e_cal_component_alarm_get_icalcomponent (alarm);
    icalprop = icalproperty_new_x ("1");
    icalproperty_set_x_name (icalprop, "X-EVOLUTION-NEEDS-DESCRIPTION");
    icalcomponent_add_property (icalcomp, icalprop);

    e_cal_component_alarm_set_action (alarm, E_CAL_COMPONENT_ALARM_DISPLAY);

    trigger.type = E_CAL_COMPONENT_ALARM_TRIGGER_RELATIVE_START;

    memset (&trigger.u.rel_duration, 0, sizeof (trigger.u.rel_duration));

    trigger.u.rel_duration.is_neg = TRUE;

    switch (default_reminder_units) {
    case E_DURATION_MINUTES:
        trigger.u.rel_duration.minutes = default_reminder_interval;
        break;

    case E_DURATION_HOURS:
        trigger.u.rel_duration.hours = default_reminder_interval;
        break;

    case E_DURATION_DAYS:
        trigger.u.rel_duration.days = default_reminder_interval;
        break;

    default:
        g_warning ("wrong units %d\n", default_reminder_units);
    }

    e_cal_component_alarm_set_trigger (alarm, trigger);

    e_cal_component_add_alarm (comp, alarm);
    e_cal_component_alarm_free (alarm);

    return comp;
}

ECalComponent *
cal_comp_event_new_with_current_time (ECalClient *client,
                                      gboolean all_day,
                                      icaltimezone *zone,
                                      gboolean use_default_reminder,
                                      gint default_reminder_interval,
                                      EDurationType default_reminder_units)
{
    ECalComponent *comp;
    struct icaltimetype itt;
    ECalComponentDateTime dt;

    comp = cal_comp_event_new_with_defaults (
        client, all_day, use_default_reminder,
        default_reminder_interval, default_reminder_units);
    g_return_val_if_fail (comp != NULL, NULL);

    if (all_day) {
        itt = icaltime_from_timet_with_zone (time (NULL), 1, zone);

        dt.value = &itt;
        dt.tzid = icaltimezone_get_tzid (zone);

        e_cal_component_set_dtstart (comp, &dt);
        e_cal_component_set_dtend (comp, &dt);
    } else {
        itt = icaltime_current_time_with_zone (zone);
        icaltime_adjust (&itt, 0, 1, -itt.minute, -itt.second);

        dt.value = &itt;
        dt.tzid = icaltimezone_get_tzid (zone);

        e_cal_component_set_dtstart (comp, &dt);
        icaltime_adjust (&itt, 0, 1, 0, 0);
        e_cal_component_set_dtend (comp, &dt);
    }

    return comp;
}

ECalComponent *
cal_comp_task_new_with_defaults (ECalClient *client)
{
    ECalComponent *comp;
    icalcomponent *icalcomp;

    if (!e_cal_client_get_default_object_sync (client, &icalcomp, NULL, NULL))
        icalcomp = icalcomponent_new (ICAL_VTODO_COMPONENT);

    comp = e_cal_component_new ();
    if (!e_cal_component_set_icalcomponent (comp, icalcomp)) {
        icalcomponent_free (icalcomp);

        e_cal_component_set_new_vtype (comp, E_CAL_COMPONENT_TODO);
    }

    return comp;
}

ECalComponent *
cal_comp_memo_new_with_defaults (ECalClient *client)
{
    ECalComponent *comp;
    icalcomponent *icalcomp;

    if (!e_cal_client_get_default_object_sync (client, &icalcomp, NULL, NULL))
        icalcomp = icalcomponent_new (ICAL_VJOURNAL_COMPONENT);

    comp = e_cal_component_new ();
    if (!e_cal_component_set_icalcomponent (comp, icalcomp)) {
        icalcomponent_free (icalcomp);

        e_cal_component_set_new_vtype (comp, E_CAL_COMPONENT_JOURNAL);
    }

    return comp;
}

void
cal_comp_update_time_by_active_window (ECalComponent *comp,
                                       EShell *shell)
{
    GtkWindow *window;

    g_return_if_fail (comp != NULL);
    g_return_if_fail (shell != NULL);

    window = e_shell_get_active_window (shell);

    if (E_IS_SHELL_WINDOW (window)) {
        EShellWindow *shell_window;
        const gchar *active_view;

        shell_window = E_SHELL_WINDOW (window);
        active_view = e_shell_window_get_active_view (shell_window);

        if (g_strcmp0 (active_view, "calendar") == 0) {
            EShellContent *shell_content;
            EShellView *shell_view;
            GnomeCalendar *gnome_cal;
            time_t start = 0, end = 0;
            icaltimezone *zone;
            struct icaltimetype itt;
            icalcomponent *icalcomp;
            icalproperty *prop;

            shell_view = e_shell_window_peek_shell_view (
                shell_window, "calendar");
            g_return_if_fail (shell_view != NULL);

            gnome_cal = NULL;
            shell_content = e_shell_view_get_shell_content (shell_view);
            g_object_get (shell_content, "calendar", &gnome_cal, NULL);
            g_return_if_fail (gnome_cal != NULL);

            gnome_calendar_get_current_time_range (gnome_cal, &start, &end);
            g_return_if_fail (start != 0);

            zone = e_cal_model_get_timezone (gnome_calendar_get_model (gnome_cal));
            itt = icaltime_from_timet_with_zone (start, FALSE, zone);

            icalcomp = e_cal_component_get_icalcomponent (comp);
            prop = icalcomponent_get_first_property (icalcomp, ICAL_DTSTART_PROPERTY);
            if (prop) {
                icalproperty_set_dtstart (prop, itt);
            } else {
                prop = icalproperty_new_dtstart (itt);
                icalcomponent_add_property (icalcomp, prop);
            }

            e_cal_component_rescan (comp);
        }
    }
}

/**
 * cal_comp_util_get_n_icons:
 * @comp: A calendar component object.
 * @pixbufs: List of pixbufs to use. Can be NULL.
 *
 * Get the number of icons owned by the component.
 * Each member of pixmaps should be freed with g_object_unref
 * and the list itself should be freed too.
 *
 * Returns: the number of icons owned by the component.
 **/
gint
cal_comp_util_get_n_icons (ECalComponent *comp,
                           GSList **pixbufs)
{
    GSList *categories_list, *elem;
    gint num_icons = 0;

    g_return_val_if_fail (comp != NULL, 0);
    g_return_val_if_fail (E_IS_CAL_COMPONENT (comp), 0);

    e_cal_component_get_categories_list (comp, &categories_list);
    for (elem = categories_list; elem; elem = elem->next) {
        const gchar *category;
        GdkPixbuf *pixbuf = NULL;

        category = elem->data;
        if (e_categories_config_get_icon_for (category, &pixbuf)) {
            if (!pixbuf)
                continue;

            num_icons++;

            if (pixbufs) {
                *pixbufs = g_slist_append (*pixbufs, pixbuf);
            } else {
                g_object_unref (pixbuf);
            }
        }
    }
    e_cal_component_free_categories_list (categories_list);

    return num_icons;
}

/**
 * cal_comp_selection_set_string_list
 * @data: Selection data, where to put list of strings.
 * @str_list: List of strings. (Each element is of type const gchar *.)
 *
 * Stores list of strings into selection target data.  Use
 * cal_comp_selection_get_string_list() to get this list from target data.
 **/
void
cal_comp_selection_set_string_list (GtkSelectionData *data,
                                    GSList *str_list)
{
    /* format is "str1\0str2\0...strN\0" */
    GSList *p;
    GByteArray *array;
    GdkAtom target;

    g_return_if_fail (data != NULL);

    if (!str_list)
        return;

    array = g_byte_array_new ();
    for (p = str_list; p; p = p->next) {
        const guint8 *c = p->data;

        if (c)
            g_byte_array_append (array, c, strlen ((const gchar *) c) + 1);
    }

    target = gtk_selection_data_get_target (data);
    gtk_selection_data_set (data, target, 8, array->data, array->len);
    g_byte_array_free (array, TRUE);
}

/**
 * cal_comp_selection_get_string_list
 * @data: Selection data, where to put list of strings.
 *
 * Converts data from selection to list of strings. Data should be assigned
 * to selection data with cal_comp_selection_set_string_list().
 * Each string in newly created list should be freed by g_free().
 * List itself should be freed by g_slist_free().
 *
 * Returns: Newly allocated #GSList of strings.
 **/
GSList *
cal_comp_selection_get_string_list (GtkSelectionData *selection_data)
{
    /* format is "str1\0str2\0...strN\0" */
    gchar *inptr, *inend;
    GSList *list;
    const guchar *data;
    gint length;

    g_return_val_if_fail (selection_data != NULL, NULL);

    data = gtk_selection_data_get_data (selection_data);
    length = gtk_selection_data_get_length (selection_data);

    list = NULL;
    inptr = (gchar *) data;
    inend = (gchar *) (data + length);

    while (inptr < inend) {
        gchar *start = inptr;

        while (inptr < inend && *inptr)
            inptr++;

        list = g_slist_prepend (list, g_strndup (start, inptr - start));

        inptr++;
    }

    return list;
}

static void
datetime_to_zone (ECalClient *client,
                  ECalComponentDateTime *date,
                  const gchar *tzid)
{
    icaltimezone *from, *to;

    g_return_if_fail (date != NULL);

    if (date->tzid == NULL || tzid == NULL ||
        date->tzid == tzid || g_str_equal (date->tzid, tzid))
        return;

    from = icaltimezone_get_builtin_timezone_from_tzid (date->tzid);
    if (!from) {
        GError *error = NULL;

        e_cal_client_get_timezone_sync (
            client, date->tzid, &from, NULL, &error);

        if (error != NULL) {
            g_warning (
                "%s: Could not get timezone '%s' from server: %s",
                G_STRFUNC, date->tzid ? date->tzid : "",
                error->message);
            g_error_free (error);
        }
    }

    to = icaltimezone_get_builtin_timezone_from_tzid (tzid);
    if (!to) {
        /* do not check failure here, maybe the zone is not available there */
        e_cal_client_get_timezone_sync (client, tzid, &to, NULL, NULL);
    }

    icaltimezone_convert_time (date->value, from, to);
    date->tzid = tzid;
}

/**
 * cal_comp_set_dtstart_with_oldzone:
 * @client: ECalClient structure, to retrieve timezone from, when required.
 * @comp: Component, where make the change.
 * @pdate: Value, to change to.
 *
 * Changes 'dtstart' of the component, but converts time to the old timezone.
 **/
void
cal_comp_set_dtstart_with_oldzone (ECalClient *client,
                                   ECalComponent *comp,
                                   const ECalComponentDateTime *pdate)
{
    ECalComponentDateTime olddate, date;

    g_return_if_fail (comp != NULL);
    g_return_if_fail (pdate != NULL);

    e_cal_component_get_dtstart (comp, &olddate);

    date = *pdate;

    datetime_to_zone (client, &date, olddate.tzid);
    e_cal_component_set_dtstart (comp, &date);

    e_cal_component_free_datetime (&olddate);
}

/**
 * cal_comp_set_dtend_with_oldzone:
 * @client: ECalClient structure, to retrieve timezone from, when required.
 * @comp: Component, where make the change.
 * @pdate: Value, to change to.
 *
 * Changes 'dtend' of the component, but converts time to the old timezone.
 **/
void
cal_comp_set_dtend_with_oldzone (ECalClient *client,
                                 ECalComponent *comp,
                                 const ECalComponentDateTime *pdate)
{
    ECalComponentDateTime olddate, date;

    g_return_if_fail (comp != NULL);
    g_return_if_fail (pdate != NULL);

    e_cal_component_get_dtend (comp, &olddate);

    date = *pdate;

    datetime_to_zone (client, &date, olddate.tzid);
    e_cal_component_set_dtend (comp, &date);

    e_cal_component_free_datetime (&olddate);
}

void
comp_util_sanitize_recurrence_master (ECalComponent *comp,
                                      ECalClient *client)
{
    ECalComponent *master = NULL;
    icalcomponent *icalcomp = NULL;
    ECalComponentRange rid;
    ECalComponentDateTime sdt;
    const gchar *uid;
    GError *error = NULL;

    /* Get the master component */
    e_cal_component_get_uid (comp, &uid);

    e_cal_client_get_object_sync (
        client, uid, NULL, &icalcomp, NULL, &error);

    if (error != NULL) {
        g_warning (
            "Unable to get the master component: %s",
            error->message);
        g_error_free (error);
        return;
    }

    master = e_cal_component_new ();
    if (!e_cal_component_set_icalcomponent (master, icalcomp)) {
        icalcomponent_free (icalcomp);
        g_object_unref (master);
        g_return_if_reached ();
        return;
    }

    /* Compare recur id and start date */
    e_cal_component_get_recurid (comp, &rid);
    e_cal_component_get_dtstart (comp, &sdt);

    if (rid.datetime.value && sdt.value &&
        icaltime_compare_date_only (
        *rid.datetime.value, *sdt.value) == 0) {
        ECalComponentDateTime msdt, medt, edt;
        gint *sequence;

        e_cal_component_get_dtstart (master, &msdt);
        e_cal_component_get_dtend (master, &medt);

        e_cal_component_get_dtend (comp, &edt);

        g_return_if_fail (msdt.value != NULL);
        g_return_if_fail (medt.value != NULL);
        g_return_if_fail (edt.value != NULL);

        sdt.value->year = msdt.value->year;
        sdt.value->month = msdt.value->month;
        sdt.value->day = msdt.value->day;

        edt.value->year = medt.value->year;
        edt.value->month = medt.value->month;
        edt.value->day = medt.value->day;

        e_cal_component_set_dtstart (comp, &sdt);
        e_cal_component_set_dtend (comp, &edt);

        e_cal_component_get_sequence (master, &sequence);
        e_cal_component_set_sequence (comp, sequence);

        e_cal_component_free_datetime (&msdt);
        e_cal_component_free_datetime (&medt);
        e_cal_component_free_datetime (&edt);
    }

    e_cal_component_free_datetime (&sdt);
    e_cal_component_free_range (&rid);
    e_cal_component_set_recurid (comp, NULL);

    g_object_unref (master);
}

gchar *
icalcomp_suggest_filename (icalcomponent *icalcomp,
                           const gchar *default_name)
{
    icalproperty *prop;
    const gchar *summary = NULL;

    if (!icalcomp)
        return g_strconcat (default_name, ".ics", NULL);

    prop = icalcomponent_get_first_property (icalcomp, ICAL_SUMMARY_PROPERTY);
    if (prop)
        summary = icalproperty_get_summary (prop);

    if (!summary || !*summary)
        summary = default_name;

    return g_strconcat (summary, ".ics", NULL);
}