path: root/calendar/gui/alarm-notify.c

/* Evolution calendar - Alarm notification engine
 *
 * Copyright (C) 2000 Helix Code, Inc.
 *
 * Authors: Federico Mena-Quintero <federico@helixcode.com>
 *
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 */

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

#include <gtk/gtksignal.h>
#include <cal-util/timeutil.h>
#include "alarm.h"
#include "alarm-notify.h"



/* Whether the notification system has been initialized */
static gboolean alarm_notify_inited;

/* Clients we are monitoring for alarms */
static GHashTable *client_alarms_hash = NULL;

/* Structure that stores a client we are monitoring */
typedef struct {
    /* Monitored client */
    CalClient *client;

    /* Number of times this client has been registered */
    int refcount;

    /* Hash table of component UID -> CompQueuedAlarms.  If an element is
     * present here, then it means its cqa->queued_alarms contains at least
     * one queued alarm.  When all the alarms for a component have been
     * dequeued, the CompQueuedAlarms structure is removed from the hash
     * table.  Thus a CQA exists <=> it has queued alarms.
     */
    GHashTable *uid_alarms_hash;
} ClientAlarms;

/* Pair of a CalComponentAlarms and the mapping from queued alarm IDs to the
 * actual alarm instance structures.
 */
typedef struct {
    /* The parent client alarms structure */
    ClientAlarms *parent_client;

    /* The actual component and its alarm instances */
    CalComponentAlarms *alarms;

    /* List of QueuedAlarm structures */
    GSList *queued_alarms;
} CompQueuedAlarms;

/* Pair of a queued alarm ID and the alarm trigger instance it refers to */
typedef struct {
    /* Alarm ID from alarm.h */
    gpointer alarm_id;

    /* Instance from our parent CompAlarms->alarms list */
    CalAlarmInstance *instance;
} QueuedAlarm;

/* Alarm ID for the midnight refresh function */
static gpointer midnight_refresh_id = NULL;



static void load_alarms (ClientAlarms *ca);
static void midnight_refresh_cb (gpointer alarm_id, time_t trigger, gpointer data);

/* Queues an alarm trigger for midnight so that we can load the next day's worth
 * of alarms.
 */
static void
queue_midnight_refresh (void)
{
    time_t midnight;

    g_assert (midnight_refresh_id == NULL);

    midnight = time_day_end (time (NULL));

    midnight_refresh_id = alarm_add (midnight, midnight_refresh_cb, NULL, NULL);
    if (!midnight_refresh_id) {
        g_message ("alarm_notify_init(): Could not set up the midnight refresh alarm!");
        /* FIXME: what to do? */
    }
}

/* Loads a client's alarms; called from g_hash_table_foreach() */
static void
add_client_alarms_cb (gpointer key, gpointer value, gpointer data)
{
    ClientAlarms *ca;

    ca = value;
    load_alarms (ca);
}

/* Loads the alarms for the new day every midnight */
static void
midnight_refresh_cb (gpointer alarm_id, time_t trigger, gpointer data)
{
    /* Re-load the alarms for all clients */

    g_hash_table_foreach (client_alarms_hash, add_client_alarms_cb, NULL);

    /* Re-schedule the midnight update */

    midnight_refresh_id = NULL;
    queue_midnight_refresh ();
}

/* Looks up a client in the client alarms hash table */
static ClientAlarms *
lookup_client (CalClient *client)
{
    return g_hash_table_lookup (client_alarms_hash, client);
}

/* Callback used when an alarm triggers */
static void
alarm_trigger_cb (gpointer alarm_id, time_t trigger, gpointer data)
{
    CompQueuedAlarms *cqa;

    cqa = data;

    /* FIXME */

    g_message ("alarm_trigger_cb(): Triggered!");
}

/* Callback used when an alarm must be destroyed */
static void
alarm_destroy_cb (gpointer alarm_id, gpointer data)
{
    CompQueuedAlarms *cqa;
    GSList *l;
    QueuedAlarm *qa;
    const char *uid;

    cqa = data;

    qa = NULL; /* Keep GCC happy */

    /* Find the alarm in the queued alarms */

    for (l = cqa->queued_alarms; l; l = l->next) {
        qa = l->data;
        if (qa->alarm_id == alarm_id)
            break;
    }

    g_assert (l != NULL);

    /* Remove it and free it */

    cqa->queued_alarms = g_slist_remove_link (cqa->queued_alarms, l);
    g_slist_free_1 (l);

    g_free (qa);

    /* If this was the last queued alarm for this component, remove the
     * component itself.
     */

    if (cqa->queued_alarms != NULL)
        return;

    cal_component_get_uid (cqa->alarms->comp, &uid);
    g_hash_table_remove (cqa->parent_client->uid_alarms_hash, uid);
    cqa->parent_client = NULL;

    cal_component_alarms_free (cqa->alarms);
    cqa->alarms = NULL;

    g_free (cqa);
}

/* Adds the alarms in a CalComponentAlarms structure to the alarms queued for a
 * particular client.  Also puts the triggers in the alarm timer queue.
 */
static void
add_component_alarms (ClientAlarms *ca, CalComponentAlarms *alarms)
{
    const char *uid;
    CompQueuedAlarms *cqa;
    GSList *l;

    cqa = g_new (CompQueuedAlarms, 1);
    cqa->parent_client = ca;
    cqa->alarms = alarms;

    cqa->queued_alarms = NULL;

    for (l = alarms->alarms; l; l = l->next) {
        CalAlarmInstance *instance;
        gpointer alarm_id;
        QueuedAlarm *qa;

        instance = l->data;

        alarm_id = alarm_add (instance->trigger, alarm_trigger_cb, cqa, alarm_destroy_cb);
        if (!alarm_id) {
            g_message ("add_component_alarms(): Could not schedule a trigger for "
                   "%ld, discarding...", (long) instance->trigger);
            continue;
        }

        qa = g_new (QueuedAlarm, 1);
        qa->alarm_id = alarm_id;
        qa->instance = instance;

        cqa->queued_alarms = g_slist_prepend (cqa->queued_alarms, qa);
    }

    cal_component_get_uid (alarms->comp, &uid);

    /* If we failed to add all the alarms, then we should get rid of the cqa */
    if (cqa->queued_alarms == NULL) {
        g_message ("add_component_alarms(): Could not add any of the alarms "
               "for the component `%s'; discarding it...", uid);

        cal_component_alarms_free (cqa->alarms);
        cqa->alarms = NULL;

        g_free (cqa);
        return;
    }

    cqa->queued_alarms = g_slist_reverse (cqa->queued_alarms);
    g_hash_table_insert (ca->uid_alarms_hash, (char *) uid, cqa);
}

/* Loads today's remaining alarms for a client */
static void
load_alarms (ClientAlarms *ca)
{
    time_t now, day_end;
    GSList *comp_alarms;
    GSList *l;

    now = time (NULL);
    day_end = time_day_end (now);

    comp_alarms = cal_client_get_alarms_in_range (ca->client, now, day_end);

    /* All of the last day's alarms should have already triggered and should
     * have been removed, so we should have no pending components.
     */
    g_assert (g_hash_table_size (ca->uid_alarms_hash) == 0);

    for (l = comp_alarms; l; l = l->next) {
        CalComponentAlarms *alarms;

        alarms = l->data;
        add_component_alarms (ca, alarms);
    }

    g_slist_free (comp_alarms);
}

/* Called when a calendar client finished loading; we load its alarms */
static void
cal_loaded_cb (CalClient *client, CalClientLoadStatus status, gpointer data)
{
    ClientAlarms *ca;

    ca = data;

    if (status != CAL_CLIENT_LOAD_SUCCESS)
        return;

    load_alarms (ca);
}

/* Looks up a component's queued alarm structure in a client alarms structure */
static CompQueuedAlarms *
lookup_comp_queued_alarms (ClientAlarms *ca, const char *uid)
{
    return g_hash_table_lookup (ca->uid_alarms_hash, uid);
}

/* Removes a component an its alarms */
static void
remove_comp (ClientAlarms *ca, const char *uid)
{
    CompQueuedAlarms *cqa;
    GSList *l;

    cqa = lookup_comp_queued_alarms (ca, uid);
    if (!cqa)
        return;

    /* If a component is present, then it means we must have alarms queued
     * for it.
     */
    g_assert (cqa->queued_alarms != NULL);

    for (l = cqa->queued_alarms; l;) {
        QueuedAlarm *qa;

        qa = l->data;

        /* Get the next element here because the list element will go
         * away.  Also, we do not free the qa here because it will be
         * freed by the destroy notification function.
         */
        l = l->next;

        alarm_remove (qa->alarm_id);
    }

    /* The list should be empty now, and thus the queued component alarms
     * structure should have been freed and removed from the hash table.
     */
    g_assert (lookup_comp_queued_alarms (ca, uid) == NULL);
}

/* Called when a calendar component changes; we must reload its corresponding
 * alarms.
 */
static void
obj_updated_cb (CalClient *client, const char *uid, gpointer data)
{
    ClientAlarms *ca;
    time_t now, day_end;
    CalComponentAlarms *alarms;
    gboolean found;

    ca = data;

    remove_comp (ca, uid);

    now = time (NULL);
    day_end = time_day_end (now);

    found = cal_client_get_alarms_for_object (ca->client, uid, now, day_end, &alarms);

    if (!found)
        return;

    add_component_alarms (ca, alarms);
}

/* Called when a calendar component is removed; we must delete its corresponding
 * alarms.
 */
static void
obj_removed_cb (CalClient *client, const char *uid, gpointer data)
{
    ClientAlarms *ca;

    ca = data;

    remove_comp (ca, uid);
}



/**
 * alarm_notify_init:
 *
 * Initializes the alarm notification system.  This should be called near the
 * beginning of the program, after calling alarm_init().
 **/
void
alarm_notify_init (void)
{
    g_return_if_fail (alarm_notify_inited == FALSE);

    client_alarms_hash = g_hash_table_new (g_direct_hash, g_direct_equal);
    queue_midnight_refresh ();

    alarm_notify_inited = TRUE;
}

/**
 * alarm_notify_done:
 *
 * Shuts down the alarm notification system.  This should be called near the end
 * of the program.  All the monitored calendar clients should already have been
 * unregistered with alarm_notify_remove_client().
 **/
void
alarm_notify_done (void)
{
    g_return_if_fail (alarm_notify_inited);

    /* All clients must be unregistered by now */
    g_return_if_fail (g_hash_table_size (client_alarms_hash) == 0);

    g_hash_table_destroy (client_alarms_hash);
    client_alarms_hash = NULL;

    g_assert (midnight_refresh_id != NULL);
    alarm_remove (midnight_refresh_id);
    midnight_refresh_id = NULL;

    alarm_notify_inited = FALSE;
}

/**
 * alarm_notify_add_client:
 * @client: A calendar client.
 *
 * Adds a calendar client to the alarm notification system.  Alarm trigger
 * notifications will be presented at the appropriate times.  The client should
 * be removed with alarm_notify_remove_client() when receiving notifications
 * from it is no longer desired.
 *
 * A client can be added any number of times to the alarm notification system,
 * but any single alarm trigger will only be presented once for a particular
 * client.  The client must still be removed the same number of times from the
 * notification system when it is no longer wanted.
 **/
void
alarm_notify_add_client (CalClient *client)
{
    ClientAlarms *ca;

    g_return_if_fail (alarm_notify_inited);
    g_return_if_fail (client != NULL);
    g_return_if_fail (IS_CAL_CLIENT (client));

    ca = lookup_client (client);
    if (ca) {
        ca->refcount++;
        return;
    }

    ca = g_new (ClientAlarms, 1);

    ca->client = client;
    gtk_object_ref (GTK_OBJECT (ca->client));

    ca->refcount = 1;
    g_hash_table_insert (client_alarms_hash, client, ca);

    ca->uid_alarms_hash = g_hash_table_new (g_str_hash, g_str_equal);

    if (!cal_client_is_loaded (client))
        gtk_signal_connect (GTK_OBJECT (client), "cal_loaded",
                    GTK_SIGNAL_FUNC (cal_loaded_cb), ca);

    gtk_signal_connect (GTK_OBJECT (client), "obj_updated",
                GTK_SIGNAL_FUNC (obj_updated_cb), ca);
    gtk_signal_connect (GTK_OBJECT (client), "obj_removed",
                GTK_SIGNAL_FUNC (obj_removed_cb), ca);

    if (cal_client_is_loaded (client))
        load_alarms (ca);
}

/**
 * alarm_notify_remove_client:
 * @client: A calendar client.
 *
 * Removes a calendar client from the alarm notification system.
 **/
void
alarm_notify_remove_client (CalClient *client)
{
    ClientAlarms *ca;

    g_return_if_fail (alarm_notify_inited);
    g_return_if_fail (client != NULL);
    g_return_if_fail (IS_CAL_CLIENT (client));

    ca = lookup_client (client);
    g_return_if_fail (ca != NULL);

    g_assert (ca->refcount > 0);
    ca->refcount--;

    if (ca->refcount > 0)
        return;

    /* FIXME: remove alarms */

    /* Clean up */

    gtk_signal_disconnect_by_data (GTK_OBJECT (ca->client), ca);

    gtk_object_unref (GTK_OBJECT (ca->client));
    ca->client = NULL;

    g_hash_table_destroy (ca->uid_alarms_hash);
    ca->uid_alarms_hash = NULL;

    g_free (ca);

    g_hash_table_remove (client_alarms_hash, client);
}