path: root/calendar/gui/calendar-config.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */

/*
 * Authors :
 *  Damon Chaplin <damon@ximian.com>
 *  Rodrigo Moya <rodrigo@ximian.com>
 *
 * Copyright 2000, Ximian, Inc.
 * Copyright 2000, Ximian, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */

/*
 * calendar-config.c - functions to load/save/get/set user settings.
 */

#include <config.h>
#include <time.h>
#include <libgnome/gnome-defs.h>
#include <libgnome/gnome-config.h>
#include <libgnomeui/gnome-dialog.h>
#include <widgets/e-timezone-dialog/e-timezone-dialog.h>
#include <cal-util/timeutil.h>
#include "component-factory.h"
#include "calendar-commands.h"
#include "e-tasks.h"
#include "e-cell-date-edit-text.h"
#include "calendar-config.h"
#include <bonobo/bonobo-exception.h>
#include <bonobo/bonobo-moniker-util.h>
#include <bonobo-conf/bonobo-config-database.h>

typedef struct
{
    gchar          *default_uri;
    gchar          *default_tasks_uri;
    gchar          *timezone;
    CalWeekdays working_days;
    gboolean    use_24_hour_format;
    gint        week_start_day;
    gint        day_start_hour;
    gint        day_start_minute;
    gint        day_end_hour;
    gint        day_end_minute;
    gint        time_divisions;
    gboolean    dnav_show_week_no;
    gint        view;
    gfloat      hpane_pos;
    gfloat      vpane_pos;
    gfloat      month_hpane_pos;
    gfloat      month_vpane_pos;
    gboolean    compress_weekend;
    gboolean    show_event_end;
    char           *tasks_due_today_color;
    char           *tasks_overdue_color;
    gboolean    hide_completed_tasks;
    CalUnits    hide_completed_tasks_units;
    gint        hide_completed_tasks_value;
    gboolean    confirm_delete;
} CalendarConfig;


static CalendarConfig *config = NULL;

static void config_read         (void);

static void on_timezone_set     (GnomeDialog    *dialog,
                     int         button,
                     ETimezoneDialog *etd);
static gboolean on_timezone_dialog_delete_event (GnomeDialog    *dialog,
                         GdkEvent   *event,
                         ETimezoneDialog *etd);

void
calendar_config_init            (void)
{
    if (config)
        return;

    config = g_new0 (CalendarConfig, 1);

    config_read ();
}

/* Returns TRUE if the locale has 'am' and 'pm' strings defined, in which
   case the user can choose between 12 and 24-hour time formats. */
gboolean
calendar_config_locale_supports_12_hour_format (void)
{  
    char s[16];
    time_t t = 0;

    strftime (s, sizeof s, "%p", gmtime (&t));
    return s[0] != '\0';
}

static void
config_read             (void)
{
    Bonobo_ConfigDatabase db;
    CORBA_Environment ev;
    char *units;

    CORBA_exception_init (&ev);
    
    db = bonobo_get_object ("wombat:", "Bonobo/ConfigDatabase", &ev);
    
    if (BONOBO_EX (&ev) || db == CORBA_OBJECT_NIL) {
        CORBA_exception_free (&ev);
        return;
    }

    CORBA_exception_free (&ev);

    config->default_uri = bonobo_config_get_string (db,
        "/Calendar/DefaultUri", NULL);

    config->default_tasks_uri = bonobo_config_get_string (db,
        "/Calendar/DefaultTasksUri", NULL);
                       
    config->timezone =  bonobo_config_get_string (db, 
                "/Calendar/Display/Timezone", NULL);

    config->working_days = bonobo_config_get_long_with_default (db, 
                "/Calendar/Display/WorkingDays", CAL_MONDAY | CAL_TUESDAY |
        CAL_WEDNESDAY | CAL_THURSDAY | CAL_FRIDAY, NULL);
 
    config->week_start_day = bonobo_config_get_long_with_default (db, 
                "/Calendar/Display/WeekStartDay", 1, NULL);
 
    /* If the locale defines 'am' and 'pm' strings then the user has the
       choice of 12-hour or 24-hour time format, with 12-hour as the
       default. If the locale doesn't have 'am' and 'pm' strings we have
       to use 24-hour format, or strftime()/strptime() won't work. */
    if (calendar_config_locale_supports_12_hour_format ()) {
        config->use_24_hour_format = bonobo_config_get_boolean_with_default (db, "/Calendar/Display/Use24HourFormat", FALSE, NULL);
    } else {
        config->use_24_hour_format = TRUE;
    }

    config->week_start_day = bonobo_config_get_long_with_default (db, 
                "/Calendar/Display/WeekStartDay", 1, NULL);
 
    config->day_start_hour = bonobo_config_get_long_with_default (db, 
                "/Calendar/Display/DayStartHour", 9, NULL);
 
    config->day_start_minute = bonobo_config_get_long_with_default (db, 
                "/Calendar/Display/DayStartMinute", 0, NULL);
 
    config->day_end_hour =  bonobo_config_get_long_with_default (db, 
                "/Calendar/Display/DayEndHour", 17, NULL);

    config->day_end_minute = bonobo_config_get_long_with_default (db, 
                "/Calendar/Display/DayEndMinute", 0, NULL);

    config->time_divisions = bonobo_config_get_long_with_default (db, 
                "/Calendar/Display/TimeDivisions", 30, NULL);

    config->view = bonobo_config_get_long_with_default (db, 
        "/Calendar/Display/View", 0, NULL);

    config->hpane_pos = bonobo_config_get_float_with_default (db, 
                "/Calendar/Display/HPanePosition", 1.0, NULL);

    config->vpane_pos = bonobo_config_get_float_with_default (db, 
                "/Calendar/Display/VPanePosition", 1.0, NULL);

    config->month_hpane_pos = bonobo_config_get_float_with_default (db, 
                "/Calendar/Display/MonthHPanePosition", 0.0, NULL);

    config->month_vpane_pos = bonobo_config_get_float_with_default (db, 
                "/Calendar/Display/MonthVPanePosition", 1.0, NULL);

    config->compress_weekend =  bonobo_config_get_boolean_with_default (db,
                "/Calendar/Display/CompressWeekend", TRUE, NULL);

    config->show_event_end =  bonobo_config_get_boolean_with_default (db, 
                "/Calendar/Display/ShowEventEndTime", TRUE, NULL);

    /* 'DateNavigator' settings. */

    config->dnav_show_week_no = bonobo_config_get_boolean_with_default (db,
                "/Calendar/DateNavigator/ShowWeekNumbers", FALSE, NULL);

    /* Task list settings */

    config->tasks_due_today_color = bonobo_config_get_string_with_default (
        db, "/Calendar/Tasks/Colors/TasksDueToday", "blue", NULL);

    config->tasks_overdue_color = bonobo_config_get_string_with_default (
        db, "/Calendar/Tasks/Colors/TasksOverdue", "red", NULL);

    config->hide_completed_tasks = bonobo_config_get_boolean_with_default (
        db, "/Calendar/Tasks/HideCompletedTasks", FALSE, NULL);

    units = bonobo_config_get_string_with_default (db,
        "/Calendar/Tasks/HideCompletedTasksUnits", "days", NULL);

    if (!strcmp (units, "minutes"))
        config->hide_completed_tasks_units = CAL_MINUTES;
    else if (!strcmp (units, "hours"))
        config->hide_completed_tasks_units = CAL_HOURS;
    else
        config->hide_completed_tasks_units = CAL_DAYS;

    config->hide_completed_tasks_value = bonobo_config_get_long_with_default (
        db, "/Calendar/Tasks/HideCompletedTasksValue", 1, NULL);

    config->confirm_delete = bonobo_config_get_boolean_with_default (
        db, "/Calendar/Other/ConfirmDelete", TRUE, NULL);

    bonobo_object_release_unref (db, NULL);
}


void
calendar_config_write           (void)
{
    Bonobo_ConfigDatabase db;
    CORBA_Environment ev;
    char *units;

    CORBA_exception_init (&ev);
    
    db = bonobo_get_object ("wombat:", "Bonobo/ConfigDatabase", &ev);
    
    if (BONOBO_EX (&ev) || db == CORBA_OBJECT_NIL) {
        CORBA_exception_free (&ev);
        return;
    }

    if (config->default_uri)
        bonobo_config_set_string (db, "/Calendar/DefaultUri",
                      config->default_uri, NULL);

    if (config->default_tasks_uri)
        bonobo_config_set_string (db, "/Calendar/DefaultTasksUri",
                      config->default_tasks_uri, NULL);

    if (config->timezone)
        bonobo_config_set_string (db, "/Calendar/Display/Timezone", 
                      config->timezone, NULL);

    bonobo_config_set_long (db, "/Calendar/Display/WorkingDays", 
                config->working_days, NULL);
    bonobo_config_set_boolean (db, "/Calendar/Display/Use24HourFormat", 
                   config->use_24_hour_format, NULL);
    bonobo_config_set_long (db, "/Calendar/Display/WeekStartDay", 
                config->week_start_day, NULL);
    bonobo_config_set_long (db, "/Calendar/Display/DayStartHour", 
                config->day_start_hour, NULL);
    bonobo_config_set_long (db, "/Calendar/Display/DayStartMinute", 
                config->day_start_minute, NULL);
    bonobo_config_set_long (db, "/Calendar/Display/DayEndHour", 
                config->day_end_hour, NULL);
    bonobo_config_set_long (db, "/Calendar/Display/DayEndMinute", 
                config->day_end_minute, NULL);
    bonobo_config_set_boolean (db, "/Calendar/Display/CompressWeekend", 
                   config->compress_weekend, NULL);
    bonobo_config_set_boolean (db, "/Calendar/Display/ShowEventEndTime", 
                   config->show_event_end, NULL);

    bonobo_config_set_boolean (db, 
                   "/Calendar/DateNavigator/ShowWeekNumbers", 
                   config->dnav_show_week_no, NULL);

    bonobo_config_set_string (db, "/Calendar/Tasks/Colors/TasksDueToday", 
                  config->tasks_due_today_color, NULL);

    bonobo_config_set_string (db, "/Calendar/Tasks/Colors/TasksOverdue", 
                  config->tasks_overdue_color, NULL);

    bonobo_config_set_boolean (db, "/Calendar/Tasks/HideCompletedTasks", 
                   config->hide_completed_tasks, NULL);

    if (config->hide_completed_tasks_units == CAL_MINUTES)
        units = "minutes";
    else if (config->hide_completed_tasks_units == CAL_HOURS)
        units = "hours";
    else
        units = "days";
    bonobo_config_set_string (db,
                  "/Calendar/Tasks/HideCompletedTasksUnits", 
                  units, NULL);
    bonobo_config_set_long (db, 
                "/Calendar/Tasks/HideCompletedTasksValue", 
                config->hide_completed_tasks_value, NULL);

    bonobo_config_set_boolean (db, "/Calendar/Other/ConfirmDelete", config->confirm_delete, NULL);

    Bonobo_ConfigDatabase_sync (db, &ev);
 
    bonobo_object_release_unref (db, NULL);

    CORBA_exception_free (&ev);
}

void
calendar_config_write_on_exit       (void)
{
    Bonobo_ConfigDatabase db;
    CORBA_Environment ev;

    CORBA_exception_init (&ev);

    db = bonobo_get_object ("wombat:", "Bonobo/ConfigDatabase", &ev);
    
    if (BONOBO_EX (&ev) || db == CORBA_OBJECT_NIL) {
        CORBA_exception_free (&ev);
        return;
    }

    bonobo_config_set_long (db, "/Calendar/Display/View", 
                config->view, NULL);
    bonobo_config_set_long (db, "/Calendar/Display/TimeDivisions", 
                config->time_divisions, NULL);
    bonobo_config_set_float (db, "/Calendar/Display/HPanePosition", 
                 config->hpane_pos, NULL);
    bonobo_config_set_float (db, "/Calendar/Display/VPanePosition", 
                 config->vpane_pos, NULL);
    bonobo_config_set_float (db, "/Calendar/Display/MonthHPanePosition", 
                 config->month_hpane_pos, NULL);
    bonobo_config_set_float (db, "/Calendar/Display/MonthVPanePosition", 
                 config->month_vpane_pos, NULL);

    Bonobo_ConfigDatabase_sync (db, &ev);
 
    bonobo_object_release_unref (db, NULL);

    CORBA_exception_free (&ev);
}


/*
 * Calendar Settings.
 */

/* The default URI is the one that will be used in places where there
   might be some action on a calendar from outside, such as adding
   a meeting request. */
gchar *
calendar_config_get_default_uri (void)
{
    return config->default_uri;
}

/* Sets the default calendar URI */
void
calendar_config_set_default_uri (gchar *default_uri)
{
    g_free (config->default_uri);

    if (default_uri && default_uri[0])
        config->default_uri = g_strdup (default_uri);
    else
        config->default_uri = NULL;
}

gchar *
calendar_config_get_default_tasks_uri (void)
{
    return config->default_tasks_uri;
}

void
calendar_config_set_default_tasks_uri (gchar *default_tasks_uri)
{
    g_free (config->default_tasks_uri);

    if (default_tasks_uri && default_tasks_uri[0])
        config->default_tasks_uri = g_strdup (default_tasks_uri);
    else
        config->default_tasks_uri = NULL;
}

/* The current timezone, e.g. "Europe/London". It may be NULL, in which case
   you should assume UTC (though Evolution will show the timezone-setting
   dialog the next time a calendar or task folder is selected). */
gchar*
calendar_config_get_timezone        (void)
{
    return config->timezone;
}


/* Sets the timezone. You shouldn't really set it to the empty string or NULL,
   as this means that Evolution will show the timezone-setting dialog to ask
   the user for the timezone. It copies the string. */
void
calendar_config_set_timezone        (gchar       *timezone)
{
    g_free (config->timezone);

    if (timezone && timezone[0])
        config->timezone = g_strdup (timezone);
    else
        config->timezone = NULL;
}


/* Whether we use 24-hour format or 12-hour format (AM/PM). */
gboolean
calendar_config_get_24_hour_format  (void)
{
    return config->use_24_hour_format;
}


void
calendar_config_set_24_hour_format  (gboolean     use_24_hour)
{
    config->use_24_hour_format = use_24_hour;
}


/* The start day of the week (0 = Sun to 6 = Mon). */
gint
calendar_config_get_week_start_day  (void)
{
    return config->week_start_day;
}


void
calendar_config_set_week_start_day  (gint         week_start_day)
{
    config->week_start_day = week_start_day;
}


/* The start and end times of the work-day. */
gint
calendar_config_get_day_start_hour  (void)
{
    return config->day_start_hour;
}


void
calendar_config_set_day_start_hour  (gint         day_start_hour)
{
    config->day_start_hour = day_start_hour;
}


gint
calendar_config_get_day_start_minute    (void)
{
    return config->day_start_minute;
}


void
calendar_config_set_day_start_minute    (gint         day_start_min)
{
    config->day_start_minute = day_start_min;
}


gint
calendar_config_get_day_end_hour    (void)
{
    return config->day_end_hour;
}


void
calendar_config_set_day_end_hour    (gint         day_end_hour)
{
    config->day_end_hour = day_end_hour;
}


gint
calendar_config_get_day_end_minute  (void)
{
    return config->day_end_minute;
}


void
calendar_config_set_day_end_minute  (gint         day_end_min)
{
    config->day_end_minute = day_end_min;
}


/* The time divisions in the Day/Work-Week view in minutes (5/10/15/30/60). */
gint
calendar_config_get_time_divisions  (void)
{
    return config->time_divisions;
}


void
calendar_config_set_time_divisions  (gint         divisions)
{
    config->time_divisions = divisions;
}


/* Whether we show week numbers in the Date Navigator. */
gboolean
calendar_config_get_dnav_show_week_no   (void)
{
    return config->dnav_show_week_no;
}


void
calendar_config_set_dnav_show_week_no   (gboolean     show_week_no)
{
    config->dnav_show_week_no = show_week_no;
}


/* The view to show on start-up, 0 = Day, 1 = WorkWeek, 2 = Week, 3 = Month. */
gint
calendar_config_get_default_view    (void)
{
    return config->view;
}


void
calendar_config_set_default_view    (gint         view)
{
    config->view = view;
}


/* The positions of the panes in the normal and month views. */
gfloat
calendar_config_get_hpane_pos       (void)
{
    return config->hpane_pos;
}


void
calendar_config_set_hpane_pos       (gfloat       hpane_pos)
{
    config->hpane_pos = hpane_pos;
}


gfloat
calendar_config_get_vpane_pos       (void)
{
    return config->vpane_pos;
}


void
calendar_config_set_vpane_pos       (gfloat       vpane_pos)
{
    config->vpane_pos = vpane_pos;
}


gfloat
calendar_config_get_month_hpane_pos (void)
{
    return config->month_hpane_pos;
}


void
calendar_config_set_month_hpane_pos (gfloat       hpane_pos)
{
    config->month_hpane_pos = hpane_pos;
}


gfloat
calendar_config_get_month_vpane_pos (void)
{
    return config->month_vpane_pos;
}


void
calendar_config_set_month_vpane_pos (gfloat       vpane_pos)
{
    config->month_vpane_pos = vpane_pos;
}


/* Whether we compress the weekend in the week/month views. */
gboolean
calendar_config_get_compress_weekend    (void)
{
    return config->compress_weekend;
}


void
calendar_config_set_compress_weekend    (gboolean     compress)
{
    config->compress_weekend = compress;
}


/* Whether we show event end times. */
gboolean
calendar_config_get_show_event_end  (void)
{
    return config->show_event_end;
}


void
calendar_config_set_show_event_end  (gboolean     show_end)
{
    config->show_event_end = show_end;
}


/* The working days of the week, a bit-wise combination of flags. */
CalWeekdays
calendar_config_get_working_days    (void)
{
    return config->working_days;
}


void
calendar_config_set_working_days    (CalWeekdays  days)
{
    config->working_days = days;
}


/* Settings to hide completed tasks. */
gboolean
calendar_config_get_hide_completed_tasks    (void)
{
    return config->hide_completed_tasks;
}


void
calendar_config_set_hide_completed_tasks    (gboolean   hide)
{
    config->hide_completed_tasks = hide;
}


CalUnits
calendar_config_get_hide_completed_tasks_units  (void)
{
    return config->hide_completed_tasks_units;
}


void
calendar_config_set_hide_completed_tasks_units  (CalUnits   units)
{
    config->hide_completed_tasks_units = units;
}


gint
calendar_config_get_hide_completed_tasks_value  (void)
{
    return config->hide_completed_tasks_value;
}


void
calendar_config_set_hide_completed_tasks_value  (gint       value)
{
    config->hide_completed_tasks_value = value;
}

/**
 * calendar_config_get_confirm_delete:
 * 
 * Queries the configuration value for whether a confirmation dialog is
 * presented when deleting calendar/tasks items.
 * 
 * Return value: Whether confirmation is required when deleting items.
 **/
gboolean
calendar_config_get_confirm_delete (void)
{
    return config->confirm_delete;
}

/**
 * calendar_config_set_confirm_delete:
 * @confirm: Whether confirmation is required when deleting items.
 * 
 * Sets the configuration value for whether a confirmation dialog is presented
 * when deleting calendar/tasks items.
 **/
void
calendar_config_set_confirm_delete (gboolean confirm)
{
    config->confirm_delete = confirm;
}


/* This sets all the common config settings for an ECalendar widget.
   These are the week start day, and whether we show week numbers. */
void
calendar_config_configure_e_calendar    (ECalendar  *cal)
{
    gboolean dnav_show_week_no;
    gint week_start_day;

    g_return_if_fail (E_IS_CALENDAR (cal));

    dnav_show_week_no = calendar_config_get_dnav_show_week_no ();

    /* Note that this is 0 (Sun) to 6 (Sat). */
    week_start_day = calendar_config_get_week_start_day ();

    /* Convert it to 0 (Mon) to 6 (Sun), which is what we use. */
    week_start_day = (week_start_day + 6) % 7;

    gnome_canvas_item_set (GNOME_CANVAS_ITEM (cal->calitem),
                   "show_week_numbers", dnav_show_week_no,
                   "week_start_day", week_start_day,
                   NULL);
}


/* This sets all the common config settings for an EDateEdit widget.
   These are the week start day, whether we show week numbers, and whether we
   use 24 hour format. */
void
calendar_config_configure_e_date_edit   (EDateEdit  *dedit)
{
    gboolean dnav_show_week_no, use_24_hour;
    gint week_start_day;

    g_return_if_fail (E_IS_DATE_EDIT (dedit));

    dnav_show_week_no = calendar_config_get_dnav_show_week_no ();

    /* Note that this is 0 (Sun) to 6 (Sat). */
    week_start_day = calendar_config_get_week_start_day ();

    /* Convert it to 0 (Mon) to 6 (Sun), which is what we use. */
    week_start_day = (week_start_day + 6) % 7;

    use_24_hour = calendar_config_get_24_hour_format ();

    e_date_edit_set_week_start_day (dedit, week_start_day);
    e_date_edit_set_show_week_numbers (dedit, dnav_show_week_no);
    e_date_edit_set_use_24_hour_format (dedit, use_24_hour);
}


/* This sets all the common config settings for an ECellDateEdit ETable item.
   These are the settings for the ECalendar popup and the time list (if we use
   24 hour format, and the hours of the working day). */
void
calendar_config_configure_e_cell_date_edit  (ECellDateEdit  *ecde)
{
    gboolean use_24_hour;
    gint start_hour, end_hour;
    ECellPopup *ecp;
    ECellDateEditText *ecd;
    char *location;
    icaltimezone *zone;

    g_return_if_fail (E_IS_CELL_DATE_EDIT (ecde));

    ecp = E_CELL_POPUP (ecde);
    ecd = E_CELL_DATE_EDIT_TEXT (ecp->child);

    location = calendar_config_get_timezone ();
    zone = icaltimezone_get_builtin_timezone (location);

    calendar_config_configure_e_calendar (E_CALENDAR (ecde->calendar));

    use_24_hour = calendar_config_get_24_hour_format ();

    start_hour = calendar_config_get_day_start_hour ();
    end_hour = calendar_config_get_day_end_hour ();

    /* Round up the end hour. */
    if (calendar_config_get_day_end_minute () != 0)
        end_hour++;

    e_cell_date_edit_freeze (ecde);
    gtk_object_set (GTK_OBJECT (ecde),
            "use_24_hour_format", use_24_hour,
#if 0
            /* We use the default 0 - 24 now. */
            "lower_hour", start_hour,
            "upper_hour", end_hour,
#endif
            NULL);
    e_cell_date_edit_thaw (ecde);

    e_cell_date_edit_text_set_timezone (ecd, zone);
    e_cell_date_edit_text_set_use_24_hour_format (ecd, use_24_hour);
}


/* This sets all the common config settings for an ECalendarTable widget.
   These are the settings for the ECalendar popup and the time list (if we use
   24 hour format, and the hours of the working day). */
void
calendar_config_configure_e_calendar_table  (ECalendarTable *cal_table)
{
    CalendarModel *model;
    gboolean use_24_hour;
    char *location;
    icaltimezone *zone;

    g_return_if_fail (E_IS_CALENDAR_TABLE (cal_table));

    use_24_hour = calendar_config_get_24_hour_format ();

    model = e_calendar_table_get_model (cal_table);
    calendar_model_set_use_24_hour_format (model, use_24_hour);

    location = calendar_config_get_timezone ();
    zone = icaltimezone_get_builtin_timezone (location);
    calendar_model_set_timezone (model, zone);

    calendar_config_configure_e_cell_date_edit (cal_table->dates_cell);

    /* Reload the event/tasks, since the 'Hide Completed Tasks' option
       may have been changed, so the query needs to be updated. */
    calendar_model_refresh (model);

    /* This is for changing the colors of the text; they will be re-fetched
     * by ECellText when the table is redrawn.
     */
    e_table_model_changed (E_TABLE_MODEL (model));
}



void
calendar_config_check_timezone_set ()
{
    ETimezoneDialog *timezone_dialog;
    GtkWidget *dialog;
    GList *elem;
    char *zone;

    zone = calendar_config_get_timezone ();
    if (zone && zone[0])
        return;

    /* Show timezone dialog. */
    timezone_dialog = e_timezone_dialog_new ();
    dialog = e_timezone_dialog_get_toplevel (timezone_dialog);

    /* Hide the cancel button, which is the 2nd button. */
    elem = g_list_nth (GNOME_DIALOG (dialog)->buttons, 1);
    gtk_widget_hide (elem->data);

    gtk_signal_connect (GTK_OBJECT (dialog), "clicked",
                GTK_SIGNAL_FUNC (on_timezone_set),
                timezone_dialog);
    gtk_signal_connect (GTK_OBJECT (dialog), "delete-event",
                GTK_SIGNAL_FUNC (on_timezone_dialog_delete_event),
                timezone_dialog);

    gtk_widget_show (dialog);
}


static void
on_timezone_set         (GnomeDialog    *dialog,
                 int         button,
                 ETimezoneDialog *etd)
{
    char *display_name;

    e_timezone_dialog_get_timezone (etd, &display_name);

    if (display_name && display_name[0]) {
        calendar_config_set_timezone (display_name);

        calendar_config_write ();
        update_all_config_settings ();
        e_tasks_update_all_config_settings ();
    }

    gtk_object_unref (GTK_OBJECT (etd));
}


static gboolean
on_timezone_dialog_delete_event (GnomeDialog    *dialog,
                 GdkEvent   *event,
                 ETimezoneDialog *etd)
{
    gtk_object_unref (GTK_OBJECT (etd));
    return TRUE;
}


/**
 * calendar_config_get_tasks_due_today_color:
 * 
 * Queries the color to be used to display tasks that are due today.
 * 
 * Return value: An X color specification.
 **/
const char *
calendar_config_get_tasks_due_today_color (void)
{
    g_assert (config->tasks_due_today_color != NULL);
    return config->tasks_due_today_color;
}

/**
 * calendar_config_set_tasks_due_today_color:
 * @color: X color specification
 * 
 * Sets the color to be used to display tasks that are due today.
 **/
void
calendar_config_set_tasks_due_today_color (const char *color)
{
    g_return_if_fail (color != NULL);

    g_assert (config->tasks_due_today_color != NULL);

    g_free (config->tasks_due_today_color);
    config->tasks_due_today_color = g_strdup (color);
}

/**
 * calendar_config_get_tasks_overdue_color:
 * 
 * Queries the color to be used to display overdue tasks.
 * 
 * Return value: An X color specification.
 **/
const char *
calendar_config_get_tasks_overdue_color (void)
{
    g_assert (config->tasks_overdue_color != NULL);
    return config->tasks_overdue_color;
}

/**
 * calendar_config_set_tasks_overdue_color:
 * @color: X color specification
 * 
 * Sets the color to be used to display overdue tasks.
 **/
void
calendar_config_set_tasks_overdue_color (const char *color)
{
    g_return_if_fail (color != NULL);

    g_assert (config->tasks_overdue_color != NULL);

    g_free (config->tasks_overdue_color);
    config->tasks_overdue_color = g_strdup (color);
}


/**
 * calendar_config_get_hide_completed_tasks_sexp:
 * 
 * Returns the subexpression to use to filter out completed tasks according
 * to the config settings. The returned sexp should be freed.
 **/
char*
calendar_config_get_hide_completed_tasks_sexp (void)
{
    char *sexp = NULL;

    if (calendar_config_get_hide_completed_tasks ()) {
        CalUnits units;
        gint value;

        units = calendar_config_get_hide_completed_tasks_units ();
        value = calendar_config_get_hide_completed_tasks_value ();

        if (value == 0) {
            /* If the value is 0, we want to hide completed tasks
               immediately, so we filter out all completed tasks.*/
            sexp = g_strdup ("(not is-completed?)");
        } else {
            char *location, *isodate;
            icaltimezone *zone;
            struct icaltimetype tt;
            time_t t;

            /* Get the current time, and subtract the appropriate
               number of days/hours/minutes. */
            location = calendar_config_get_timezone ();
            zone = icaltimezone_get_builtin_timezone (location);
            tt = icaltime_current_time_with_zone (zone);

            switch (units) {
            case CAL_DAYS:
                icaltime_adjust (&tt, -value, 0, 0, 0);
                break;
            case CAL_HOURS:
                icaltime_adjust (&tt, 0, -value, 0, 0);
                break;
            case CAL_MINUTES:
                icaltime_adjust (&tt, 0, 0, -value, 0);
                break;
            default:
                g_assert_not_reached ();
            }

            t = icaltime_as_timet_with_zone (tt, zone);

            /* Convert the time to an ISO date string, and build
               the query sub-expression. */
            isodate = isodate_from_time_t (t);
            sexp = g_strdup_printf ("(not (completed-before? (make-time \"%s\")))", isodate);
        }
    }

    return sexp;
}