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

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

/* Evolution calendar - Data model for ETable
 *
 * 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.
 */

/* We need this for strptime. */
#define _XOPEN_SOURCE

#include <config.h>
#include <ctype.h>
#include <math.h>
#undef _XOPEN_SOURCE
#include <sys/time.h>
#define _XOPEN_SOURCE
#include <time.h>
#include <gnome.h>
#include <cal-util/timeutil.h>
#include "calendar-model.h"
#include "calendar-commands.h"



/* Private part of the ECalendarModel structure */
typedef struct {
    /* Calendar client we are using */
    CalClient *client;

    /* Types of objects we are dealing with */
    CalObjType type;

    /* Array of pointers to calendar objects */
    GArray *objects;

    /* UID -> array index hash */
    GHashTable *uid_index_hash;

    /* HACK: so that ETable can do its stupid append_row() thing */
    guint appending_row : 1;
} CalendarModelPrivate;



static void calendar_model_class_init (CalendarModelClass *class);
static void calendar_model_init (CalendarModel *model);
static void calendar_model_destroy (GtkObject *object);

static int calendar_model_column_count (ETableModel *etm);
static int calendar_model_row_count (ETableModel *etm);
static void *calendar_model_value_at (ETableModel *etm, int col, int row);
static void calendar_model_set_value_at (ETableModel *etm, int col, int row, const void *value);
static gboolean calendar_model_is_cell_editable (ETableModel *etm, int col, int row);
static void calendar_model_append_row (ETableModel *etm, ETableModel *source, gint row);
static void *calendar_model_duplicate_value (ETableModel *etm, int col, const void *value);
static void calendar_model_free_value (ETableModel *etm, int col, void *value);
static void *calendar_model_initialize_value (ETableModel *etm, int col);
static gboolean calendar_model_value_is_empty (ETableModel *etm, int col, const void *value);
#if 0
static char * calendar_model_value_to_string (ETableModel *etm, int col, const void *value);
#endif
static void load_objects (CalendarModel *model);
static int remove_object (CalendarModel *model, const char *uid);

static ETableModelClass *parent_class;



/**
 * calendar_model_get_type:
 * @void:
 *
 * Registers the #CalendarModel class if necessary, and returns the type ID
 * associated to it.
 *
 * Return value: The type ID of the #CalendarModel class.
 **/
GtkType
calendar_model_get_type (void)
{
    static GtkType calendar_model_type = 0;

    if (!calendar_model_type) {
        static GtkTypeInfo calendar_model_info = {
            "CalendarModel",
            sizeof (CalendarModel),
            sizeof (CalendarModelClass),
            (GtkClassInitFunc) calendar_model_class_init,
            (GtkObjectInitFunc) calendar_model_init,
            NULL, /* reserved_1 */
            NULL, /* reserved_2 */
            (GtkClassInitFunc) NULL
        };

        calendar_model_type = gtk_type_unique (E_TABLE_MODEL_TYPE, &calendar_model_info);
    }

    return calendar_model_type;
}

/* Class initialization function for the calendar table model */
static void
calendar_model_class_init (CalendarModelClass *class)
{
    GtkObjectClass *object_class;
    ETableModelClass *etm_class;

    object_class = (GtkObjectClass *) class;
    etm_class = (ETableModelClass *) class;

    parent_class = gtk_type_class (E_TABLE_MODEL_TYPE);

    object_class->destroy = calendar_model_destroy;

    etm_class->column_count = calendar_model_column_count;
    etm_class->row_count = calendar_model_row_count;
    etm_class->value_at = calendar_model_value_at;
    etm_class->set_value_at = calendar_model_set_value_at;
    etm_class->is_cell_editable = calendar_model_is_cell_editable;
    etm_class->append_row = calendar_model_append_row;
    etm_class->duplicate_value = calendar_model_duplicate_value;
    etm_class->free_value = calendar_model_free_value;
    etm_class->initialize_value = calendar_model_initialize_value;
    etm_class->value_is_empty = calendar_model_value_is_empty;
#if 0
    etm_class->value_to_string = calendar_model_value_to_string;
#endif
}

/* Object initialization function for the calendar table model */
static void
calendar_model_init (CalendarModel *model)
{
    CalendarModelPrivate *priv;

    priv = g_new0 (CalendarModelPrivate, 1);
    model->priv = priv;

    priv->objects = g_array_new (FALSE, TRUE, sizeof (CalComponent *));
    priv->uid_index_hash = g_hash_table_new (g_str_hash, g_str_equal);
}

/* Called from g_hash_table_foreach_remove(), frees a stored UID->index
 * mapping.
 */
static gboolean
free_uid_index (gpointer key, gpointer value, gpointer data)
{
    int *idx;

    idx = value;
    g_free (idx);

    return TRUE;
}

/* Frees the objects stored in the calendar model */
static void
free_objects (CalendarModel *model)
{
    CalendarModelPrivate *priv;
    int i;

    priv = model->priv;

    g_hash_table_foreach_remove (priv->uid_index_hash, free_uid_index, NULL);

    for (i = 0; i < priv->objects->len; i++) {
        CalComponent *comp;

        comp = g_array_index (priv->objects, CalComponent *, i);
        g_assert (comp != NULL);
        gtk_object_unref (GTK_OBJECT (comp));
    }

    g_array_set_size (priv->objects, 0);
}

/* Destroy handler for the calendar table model */
static void
calendar_model_destroy (GtkObject *object)
{
    CalendarModel *model;
    CalendarModelPrivate *priv;

    g_return_if_fail (object != NULL);
    g_return_if_fail (IS_CALENDAR_MODEL (object));

    model = CALENDAR_MODEL (object);
    priv = model->priv;

    /* Free the calendar client interface object */

    if (priv->client) {
        gtk_signal_disconnect_by_data (GTK_OBJECT (priv->client), model);
        gtk_object_unref (GTK_OBJECT (priv->client));
        priv->client = NULL;
    }

    /* Free the uid->index hash data and the array of UIDs */

    free_objects (model);

    g_hash_table_destroy (priv->uid_index_hash);
    priv->uid_index_hash = NULL;

    g_array_free (priv->objects, TRUE);
    priv->objects = NULL;

    /* Free the private structure */

    g_free (priv);
    model->priv = NULL;

    if (GTK_OBJECT_CLASS (parent_class)->destroy)
        (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
}



/* ETableModel methods */

/* column_count handler for the calendar table model */
static int
calendar_model_column_count (ETableModel *etm)
{
    return CAL_COMPONENT_FIELD_NUM_FIELDS;
}

/* row_count handler for the calendar table model */
static int
calendar_model_row_count (ETableModel *etm)
{
    CalendarModel *model;
    CalendarModelPrivate *priv;

    model = CALENDAR_MODEL (etm);
    priv = model->priv;

    return priv->objects->len;
}

/* Creates a nice string representation of a time value */
static char*
get_time_t (time_t *t, gboolean skip_midnight)
{
    static char buffer[32];
    struct tm *tmp_tm;

    if (*t <= 0) {
        buffer[0] = '\0';
    } else {
        tmp_tm = localtime (t);

        if (skip_midnight && tmp_tm->tm_hour == 0
            && tmp_tm->tm_min == 0 && tmp_tm->tm_sec == 0)
            strftime (buffer, 32, "%a %x", tmp_tm);
        else
            strftime (buffer, 32, "%a %x %T", tmp_tm);
    }

    return buffer;
}

/* Builds a string based on the list of CATEGORIES properties of a calendar
 * component.
 */
static char *
get_categories (CalComponent *comp)
{
    GSList *categories;
    GString *str;
    char *s;
    GSList *l;

    cal_component_get_categories_list (comp, &categories);

    str = g_string_new (NULL);

    for (l = categories; l; l = l->next) {
        const char *category;

        category = l->data;
        g_string_append (str, category);

        if (l->next != NULL)
            g_string_append (str, ", ");
    }

    s = str->str;

    g_string_free (str, FALSE);
    cal_component_free_categories_list (categories);

    return s;
}

/* Returns a string based on the CLASSIFICATION property of a calendar component */
static char *
get_classification (CalComponent *comp)
{
    CalComponentClassification classif;

    cal_component_get_classification (comp, &classif);

    switch (classif) {
    case CAL_COMPONENT_CLASS_NONE:
        return "";

    case CAL_COMPONENT_CLASS_PUBLIC:
        return _("Public");

    case CAL_COMPONENT_CLASS_PRIVATE:
        return _("Private");

    case CAL_COMPONENT_CLASS_CONFIDENTIAL:
        return _("Confidential");

    case CAL_COMPONENT_CLASS_UNKNOWN:
        return _("Unknown");

    default:
        g_assert_not_reached ();
        return NULL;
    }
}

/* Builds a string for the COMPLETED property of a calendar component */
static char *
get_completed (CalComponent *comp)
{
    struct icaltimetype *completed;
    time_t t;

    cal_component_get_completed (comp, &completed);

    if (!completed)
        t = 0;
    else {
        t = time_from_icaltimetype (*completed);
        cal_component_free_icaltimetype (completed);
    }

    return get_time_t (&t, FALSE);
}

/* Builds a string for and frees a date/time value */
static char *
get_and_free_datetime (CalComponentDateTime dt)
{
    time_t t;

    if (!dt.value)
        t = 0;
    else
        t = time_from_icaltimetype (*dt.value);

    cal_component_free_datetime (&dt);

    return get_time_t (&t, FALSE);
}

/* Builds a string for the DTEND property of a calendar component */
static char *
get_dtend (CalComponent *comp)
{
    CalComponentDateTime dt;

    cal_component_get_dtend (comp, &dt);
    return get_and_free_datetime (dt);
}

/* Builds a string for the DTSTART property of a calendar component */
static char *
get_dtstart (CalComponent *comp)
{
    CalComponentDateTime dt;

    cal_component_get_dtstart (comp, &dt);
    return get_and_free_datetime (dt);
}

/* Builds a string for the DUE property of a calendar component */
static char *
get_due (CalComponent *comp)
{
    CalComponentDateTime dt;

    cal_component_get_due (comp, &dt);
    return get_and_free_datetime (dt);
}

/* Builds a string for the GEO property of a calendar component */
static char*
get_geo (CalComponent *comp)
{
    struct icalgeotype *geo;
    static gchar buf[32];

    cal_component_get_geo (comp, &geo);

    if (!geo)
        buf[0] = '\0';
    else {
        g_snprintf (buf, sizeof (buf), "%g %s, %g %s",
                fabs (geo->lat),
                geo->lat >= 0.0 ? _("N") : _("S"),
                fabs (geo->lon),
                geo->lon >= 0.0 ? _("E") : _("W"));
        cal_component_free_geo (geo);
    }

    return buf;
}

/* Builds a string for the PERCENT property of a calendar component */
static char *
get_percent (CalComponent *comp)
{
    int *percent;
    static char buf[32];

    cal_component_get_percent (comp, &percent);

    if (!percent)
        buf[0] = '\0';
    else {
        g_snprintf (buf, sizeof (buf), "%d%%", *percent);
        cal_component_free_percent (percent);
    }

    return buf;
}

/* Builds a string for the PRIORITY property of a calendar component */
static char *
get_priority (CalComponent *comp)
{
    int *priority;
    static char buf[32];

    cal_component_get_priority (comp, &priority);

    if (!priority)
        buf[0] = '\0';
    else {
        g_snprintf (buf, sizeof (buf), "%d", *priority);
        cal_component_free_priority (priority);
    }

    return buf;
}

/* Builds a string for the SUMMARY property of a calendar component */
static char *
get_summary (CalComponent *comp)
{
    CalComponentText summary;

    cal_component_get_summary (comp, &summary);

    if (summary.value)
        return (char *) summary.value;
    else
        return "";
}

/* Builds a string for the TRANSPARENCY property of a calendar component */
static char *
get_transparency (CalComponent *comp)
{
    CalComponentTransparency transp;

    cal_component_get_transparency (comp, &transp);

    switch (transp) {
    case CAL_COMPONENT_TRANSP_NONE:
        return "";

    case CAL_COMPONENT_TRANSP_TRANSPARENT:
        return _("Transparent");

    case CAL_COMPONENT_TRANSP_OPAQUE:
        return _("Opaque");

    case CAL_COMPONENT_TRANSP_UNKNOWN:
        return _("Unknown");

    default:
        g_assert_not_reached ();
        return NULL;
    }
}

/* Builds a string for the URL property of a calendar component */
static char *
get_url (CalComponent *comp)
{
    const char *url;

    cal_component_get_url (comp, &url);

    if (url)
        return (char *) url;
    else
        return "";
}

/* Returns whether the component has any alarms defined for it */
static gboolean
get_has_alarms (CalComponent *comp)
{
    CalComponentAlarm *alarm;
    gboolean retval;

    alarm = cal_component_get_first_alarm (comp);
    retval = (alarm != NULL);

    cal_component_alarm_free (alarm);
    return retval;
}

/* Returns whether the component has any recurrences defined for it */
static gboolean
get_has_recurrences (CalComponent *comp)
{
    return cal_component_has_rdates (comp) || cal_component_has_rrules (comp);
}

/* Returns whether the completion date has been set on a component */
static gboolean
get_is_complete (CalComponent *comp)
{
    struct icaltimetype *t;
    gboolean retval;

    cal_component_get_completed (comp, &t);
    retval = (t != NULL);

    cal_component_free_icaltimetype (t);
    return retval;
}

/* Returns whether a calendar component is overdue.
 *
 * FIXME: This will only get called when the component is scrolled into the
 * ETable.  There should be some sort of dynamic update thingy for if a component
 * becomes overdue while it is being viewed.
 */
static gboolean
get_is_overdue (CalComponent *comp)
{
    CalComponentDateTime dt;
    gboolean retval;

    cal_component_get_due (comp, &dt);

    /* First, do we have a due date? */

    if (!dt.value)
        retval = FALSE;
    else {
        struct icaltimetype *completed;
        time_t t;

        /* Second, is it already completed? */

        cal_component_get_completed (comp, &completed);

        if (completed) {
            retval = FALSE;

            cal_component_free_icaltimetype (completed);
            goto out;
        }

        /* Third, are we overdue as of right now?
         *
         * FIXME: should we check the PERCENT as well?  If it is at 100%
         * but the COMPLETED property is not set, is the component
         * really overdue?
         **/

        t = time_from_icaltimetype (*dt.value);

        if (t < time (NULL))
            retval = TRUE;
        else
            retval = FALSE;
    }

 out:

    cal_component_free_datetime (&dt);

    return retval;
}

/* value_at handler for the calendar table model */
static void *
calendar_model_value_at (ETableModel *etm, int col, int row)
{
    CalendarModel *model;
    CalendarModelPrivate *priv;
    CalComponent *comp;

    model = CALENDAR_MODEL (etm);
    priv = model->priv;

    g_return_val_if_fail (col >= 0 && col < CAL_COMPONENT_FIELD_NUM_FIELDS, NULL);
    g_return_val_if_fail (row >= 0 && row < priv->objects->len, NULL);

    comp = g_array_index (priv->objects, CalComponent *, row);
    g_assert (comp != NULL);

    switch (col) {
    case CAL_COMPONENT_FIELD_CATEGORIES:
        return get_categories (comp);

    case CAL_COMPONENT_FIELD_CLASSIFICATION:
        return get_classification (comp);

    case CAL_COMPONENT_FIELD_COMPLETED:
        return get_completed (comp);

    case CAL_COMPONENT_FIELD_DTEND:
        return get_dtend (comp);

    case CAL_COMPONENT_FIELD_DTSTART:
        return get_dtstart (comp);

    case CAL_COMPONENT_FIELD_DUE:
        return get_due (comp);

    case CAL_COMPONENT_FIELD_GEO:
        return get_geo (comp);

    case CAL_COMPONENT_FIELD_PERCENT:
        return get_percent (comp);

    case CAL_COMPONENT_FIELD_PRIORITY:
        return get_priority (comp);

    case CAL_COMPONENT_FIELD_SUMMARY:
        return get_summary (comp);

    case CAL_COMPONENT_FIELD_TRANSPARENCY:
        return get_transparency (comp);

    case CAL_COMPONENT_FIELD_URL:
        return get_url (comp);

    case CAL_COMPONENT_FIELD_HAS_ALARMS:
        return GINT_TO_POINTER (get_has_alarms (comp));

    case CAL_COMPONENT_FIELD_ICON:
        /* FIXME: Also support 'Assigned to me' & 'Assigned to someone
           else'. */
        if (get_has_recurrences (comp))
            return GINT_TO_POINTER (1);
        else
            return GINT_TO_POINTER (0);

    case CAL_COMPONENT_FIELD_COMPLETE:
        return GINT_TO_POINTER (get_is_complete (comp));

    case CAL_COMPONENT_FIELD_RECURRING:
        return GINT_TO_POINTER (get_has_recurrences (comp));

    case CAL_COMPONENT_FIELD_OVERDUE:
        return GINT_TO_POINTER (get_is_overdue (comp));

    case CAL_COMPONENT_FIELD_COLOR:
        if (get_is_overdue (comp))
            return "red";
        else
            return NULL;

    default:
        g_message ("calendar_model_value_at(): Requested invalid column %d", col);
        return NULL;
    }
}

/* Returns whether a string is NULL, empty, or full of whitespace */
static gboolean
string_is_empty (const char *value)
{
    const char *p;
    gboolean empty = TRUE;

    if (value) {
        p = value;
        while (*p) {
            if (!isspace (*p)) {
                empty = FALSE;
                break;
            }
            p++;
        }
    }
    return empty;
}


/* FIXME: We need to set the "transient_for" property for the dialog, but
   the model doesn't know anything about the windows. */
static void
show_date_warning (void)
{
    GtkWidget *dialog;
    char buffer[32], message[256];
    time_t t;
    struct tm *tmp_tm;

    t = time (NULL);
    tmp_tm = localtime (&t);
    strftime (buffer, 32, "%a %x %T", tmp_tm);

    g_snprintf (message, 256,
            _("The date must be entered in the format: \n\n%s"),
            buffer);

    dialog = gnome_message_box_new (message,
                    GNOME_MESSAGE_BOX_ERROR,
                    GNOME_STOCK_BUTTON_OK, NULL);
    gtk_widget_show (dialog);
}

/* Builds a list of categories from a comma-delimited string */
static GSList *
categories_from_string (const char *value)
{
    GSList *list;
    const char *categ_start;
    const char *categ_end;
    const char *p;

    if (!value)
        return NULL;

    list = NULL;

    categ_start = categ_end = NULL;

    for (p = value; *p; p++) {
        if (categ_start) {
            if (*p == ',') {
                char *c;

                c = g_strndup (categ_start, categ_end - categ_start + 1);
                list = g_slist_prepend (list, c);

                categ_start = categ_end = NULL;
            } else if (!isspace (*p))
                categ_end = p;
        } else if (!isspace (*p) && *p != ',')
            categ_start = categ_end = p;
    }

    if (categ_start) {
        char *c;

        c = g_strndup (categ_start, categ_end - categ_start + 1);
        list = g_slist_prepend (list, c);
    }

    return g_slist_reverse (list);
}

/* Sets the list of categories from a comma-delimited string */
static void
set_categories (CalComponent *comp, const char *value)
{
    GSList *list;
    GSList *l;

    list = categories_from_string (value);

    cal_component_set_categories_list (comp, list);

    for (l = list; l; l = l->next) {
        char *s;

        s = l->data;
        g_free (s);
    }

    g_slist_free (list);
}

/* Parses a time value entered by the user; returns -1 if it could not be
 * parsed.  Returns 0 for an empty time.
 */
static time_t
parse_time (const char *value)
{
    struct tm tmp_tm;
    struct tm *today_tm;
    time_t t;
    const char *p;

    if (string_is_empty (value))
        return 0;

    /* Skip any weekday name. */
    p = strptime (value, "%a", &tmp_tm);
    if (!p)
        p = value;

    /* Try to match the full date & time, or without the seconds,
       or just the date, or just the time with/without seconds.
       The info pages say we should clear the tm before calling
       strptime. It also means that if we don't match a time we
       get 00:00:00 which is good. */
    memset (&tmp_tm, 0, sizeof (tmp_tm));
    if (!strptime (value, "%x %T", &tmp_tm)) {
        memset (&tmp_tm, 0, sizeof (tmp_tm));
        if (!strptime (value, "%x %H:%M", &tmp_tm)) {
            memset (&tmp_tm, 0, sizeof (tmp_tm));
            if (!strptime (value, "%x", &tmp_tm)) {
                memset (&tmp_tm, 0, sizeof (tmp_tm));
                if (!strptime (value, "%T", &tmp_tm)) {
                    memset (&tmp_tm, 0, sizeof (tmp_tm));
                    if (!strptime (value, "%H:%M", &tmp_tm))
                        return -1; /* Could not parse it */
                }

                /* We only got a time, so we use the
                   current day. */
                t = time (NULL);
                today_tm = localtime (&t);
                tmp_tm.tm_mday = today_tm->tm_mday;
                tmp_tm.tm_mon  = today_tm->tm_mon;
                tmp_tm.tm_year = today_tm->tm_year;
            }
        }
    }

    tmp_tm.tm_isdst = -1;
    return mktime (&tmp_tm);
}

/* Sets the completion time of a component */
static void
set_completed (CalComponent *comp, const char *value)
{
    time_t t;
    struct icaltimetype itt;

    t = parse_time (value);
    if (t == -1) {
        show_date_warning ();
        return;
    } else if (t == 0) {
        cal_component_set_completed (comp, NULL);
        return;
    } else {
        itt = icaltimetype_from_timet (t, FALSE);
        cal_component_set_completed (comp, &itt);
    }
}

/* Sets a CalComponentDateTime value */
static void
set_datetime (CalComponent *comp, const char *value,
          void (* set_func) (CalComponent *comp, CalComponentDateTime *dt))
{
    time_t t;

    t = parse_time (value);
    if (t == -1) {
        show_date_warning ();
        return;
    } else if (t == 0) {
        (* set_func) (comp, NULL);
        return;
    } else {
        CalComponentDateTime dt;
        struct icaltimetype itt;

        itt = icaltimetype_from_timet (t, FALSE);
        dt.value = &itt;
        dt.tzid = NULL;

        (* set_func) (comp, &dt);
    }
}

/* FIXME: We need to set the "transient_for" property for the dialog, but the
 * model doesn't know anything about the windows.
 */
static void
show_geo_warning (void)
{
    GtkWidget *dialog;

    dialog = gnome_message_box_new (_("The geographical position must be entered "
                      "in the format: \n\n45.436845,125.862501"),
                    GNOME_MESSAGE_BOX_ERROR,
                    GNOME_STOCK_BUTTON_OK, NULL);
    gtk_widget_show (dialog);
}

/* Sets the geographical position value of a component */
static void
set_geo (CalComponent *comp, const char *value)
{
    double latitude, longitude;
    int matched;
    struct icalgeotype geo;

    if (string_is_empty (value)) {
        cal_component_set_geo (comp, NULL);
        return;
    }

    matched = sscanf (value, "%lg , %lg", &latitude, &longitude);

    if (matched != 2) {
        show_geo_warning ();
        return;
    }

    geo.lat = latitude;
    geo.lon = longitude;
    cal_component_set_geo (comp, &geo);
}

/* FIXME: We need to set the "transient_for" property for the dialog, but the
 * model doesn't know anything about the windows.
 */
static void
show_percent_warning (void)
{
    GtkWidget *dialog;

    dialog = gnome_message_box_new (_("The percent value must be between 0 and 100, inclusive"),
                    GNOME_MESSAGE_BOX_ERROR,
                    GNOME_STOCK_BUTTON_OK, NULL);
    gtk_widget_show (dialog);
}

/* Sets the percent value of a calendar component */
static void
set_percent (CalComponent *comp, const char *value)
{
    int matched, percent;

    if (string_is_empty (value)) {
        cal_component_set_percent (comp, NULL);
        return;
    }

    matched = sscanf (value, "%i", &percent);

    if (matched != 1 || percent < 0 || percent > 100) {
        show_percent_warning ();
        return;
    }

    cal_component_set_percent (comp, &percent);
}

/* FIXME: We need to set the "transient_for" property for the dialog, but the
 * model doesn't know anything about the windows.  */
static void
show_priority_warning (void)
{
    GtkWidget *dialog;

    dialog = gnome_message_box_new (_("The priority must be between 1 and 9, inclusive"),
                    GNOME_MESSAGE_BOX_ERROR,
                    GNOME_STOCK_BUTTON_OK, NULL);
    gtk_widget_show (dialog);
}

/* Sets the priority of a calendar component */
static void
set_priority (CalComponent *comp, const char *value)
{
    int matched, priority;

    if (string_is_empty (value)) {
        cal_component_set_priority (comp, NULL);
        return;
    }

    matched = sscanf (value, "%i", &priority);

    if (matched != 1 || priority < 1 || priority > 9) {
        show_priority_warning ();
        return;
    }

    cal_component_set_priority (comp, &priority);
}

/* Sets the summary of a calendar component */
static void
set_summary (CalComponent *comp, const char *value)
{
    CalComponentText text;

    if (string_is_empty (value)) {
        cal_component_set_summary (comp, NULL);
        return;
    }

    text.value = value;
    text.altrep = NULL; /* FIXME: should we preserve the old ALTREP? */

    cal_component_set_summary (comp, &text);
}

/* Sets the URI of a calendar component */
static void
set_url (CalComponent *comp, const char *value)
{
    if (string_is_empty (value)) {
        cal_component_set_url (comp, NULL);
        return;
    }

    cal_component_set_url (comp, value);
}

/* set_value_at handler for the calendar table model */
static void
calendar_model_set_value_at (ETableModel *etm, int col, int row, const void *value)
{
    CalendarModel *model;
    CalendarModelPrivate *priv;
    CalComponent *comp;

    model = CALENDAR_MODEL (etm);
    priv = model->priv;

    g_return_if_fail (col >= 0 && col < CAL_COMPONENT_FIELD_NUM_FIELDS);
    g_return_if_fail (row >= 0 && row < priv->objects->len);

    comp = g_array_index (priv->objects, CalComponent *, row);
    g_assert (comp != NULL);

    switch (col) {
    case CAL_COMPONENT_FIELD_CATEGORIES:
        set_categories (comp, value);
        break;

    /* FIXME: CLASSIFICATION requires an option menu cell renderer */

    case CAL_COMPONENT_FIELD_COMPLETED:
        set_completed (comp, value);
        break;

    case CAL_COMPONENT_FIELD_DTEND:
        /* FIXME: Need to reset dtstart if dtend happens before it */
        set_datetime (comp, value, cal_component_set_dtend);
        break;

    case CAL_COMPONENT_FIELD_DTSTART:
        /* FIXME: Need to reset dtend if dtstart happens after it */
        set_datetime (comp, value, cal_component_set_dtstart);
        break;

    case CAL_COMPONENT_FIELD_DUE:
        set_datetime (comp, value, cal_component_set_due);
        break;

    case CAL_COMPONENT_FIELD_GEO:
        set_geo (comp, value);
        break;

    case CAL_COMPONENT_FIELD_PERCENT:
        set_percent (comp, value);
        break;

    case CAL_COMPONENT_FIELD_PRIORITY:
        set_priority (comp, value);
        break;

    case CAL_COMPONENT_FIELD_SUMMARY:
        set_summary (comp, value);
        break;

    /* FIXME: TRANSPARENCY requires an option menu cell renderer */

    case CAL_COMPONENT_FIELD_URL:
        set_url (comp, value);
        break;

    default:
        g_message ("calendar_model_set_value_at(): Requested invalid column %d", col);
        break;
    }

    /* FIXME: this is an ugly HACK.  ETable needs a better API for the
     * "click here to add an element" thingy.
     */
    if (priv->appending_row)
        return;

    if (!cal_client_update_object (priv->client, comp))
        g_message ("calendar_model_set_value_at(): Could not update the object!");
}

/* is_cell_editable handler for the calendar table model */
static gboolean
calendar_model_is_cell_editable (ETableModel *etm, int col, int row)
{
    CalendarModel *model;
    CalendarModelPrivate *priv;

    model = CALENDAR_MODEL (etm);
    priv = model->priv;

    g_return_val_if_fail (col >= 0 && col < CAL_COMPONENT_FIELD_NUM_FIELDS, FALSE);

    /* FIXME: We can't check this as 'click-to-add' passes row 0. */
    /*g_return_val_if_fail (row >= 0 && row < priv->objects->len, FALSE);*/

    switch (col) {
    case CAL_COMPONENT_FIELD_CATEGORIES:
    case CAL_COMPONENT_FIELD_COMPLETED:
    case CAL_COMPONENT_FIELD_DTEND:
    case CAL_COMPONENT_FIELD_DTSTART:
    case CAL_COMPONENT_FIELD_DUE:
    case CAL_COMPONENT_FIELD_GEO:
    case CAL_COMPONENT_FIELD_PERCENT:
    case CAL_COMPONENT_FIELD_PRIORITY:
    case CAL_COMPONENT_FIELD_SUMMARY:
    case CAL_COMPONENT_FIELD_URL:
        return TRUE;

    default:
        return FALSE;
    }
}

/* append_row handler for the calendar model */
static void
calendar_model_append_row (ETableModel *etm, ETableModel *source, gint row)
{
    CalendarModel *model;
    CalendarModelPrivate *priv;
    CalComponent *comp;
    int *new_idx, col;
    const char *uid;

    model = CALENDAR_MODEL (etm);
    priv = model->priv;

    /* This is a HACK */
    priv->appending_row = TRUE;

    /* FIXME: This should support other types of components, but for now it
     * is only used for the task list.
     */
    comp = cal_component_new ();
    cal_component_set_new_vtype (comp, CAL_COMPONENT_TODO);

    cal_component_get_uid (comp, &uid);

    g_array_append_val (priv->objects, comp);
    new_idx = g_new (int, 1);
    *new_idx = priv->objects->len - 1;
    g_hash_table_insert (priv->uid_index_hash, (char *) uid, new_idx);

    /* Notify the views about the new row. I think we have to do that here,
       or the views may become confused when they start getting
       "row_changed" or "cell_changed" signals for this new row. */
    e_table_model_row_inserted (etm, *new_idx);

    for (col = 0; col < CAL_COMPONENT_FIELD_NUM_FIELDS; col++) {
        const void *val;

        if (!e_table_model_is_cell_editable (etm, col, *new_idx))
            continue;

        val = e_table_model_value_at(source, col, row);
        e_table_model_set_value_at (etm, col, *new_idx, val);
    }

    /* This is the end of the HACK */
    priv->appending_row = FALSE;

    if (!cal_client_update_object (priv->client, comp)) {
        /* FIXME: Show error dialog. */
        g_message ("calendar_model_append_row(): Could not add new object!");
        remove_object (model, uid);
        e_table_model_row_deleted (etm, *new_idx);
    }
}

/* Duplicates a string value */
static char *
dup_string (const char *value)
{
    return g_strdup (value);
}

/* duplicate_value handler for the calendar table model */
static void *
calendar_model_duplicate_value (ETableModel *etm, int col, const void *value)
{
    g_return_val_if_fail (col >= 0 && col < CAL_COMPONENT_FIELD_NUM_FIELDS, NULL);

    /* They are almost all dup_string()s for now, but we'll have real fields
     * later.
     */

    switch (col) {
    case CAL_COMPONENT_FIELD_CATEGORIES:
        return dup_string (value);

    case CAL_COMPONENT_FIELD_CLASSIFICATION:
        return (void *) value;

    case CAL_COMPONENT_FIELD_COMPLETED:
    case CAL_COMPONENT_FIELD_DTEND:
    case CAL_COMPONENT_FIELD_DTSTART:
    case CAL_COMPONENT_FIELD_DUE:
    case CAL_COMPONENT_FIELD_GEO:
    case CAL_COMPONENT_FIELD_PERCENT:
    case CAL_COMPONENT_FIELD_PRIORITY:
        return dup_string (value);

    case CAL_COMPONENT_FIELD_TRANSPARENCY:
        return (void *) value;

    case CAL_COMPONENT_FIELD_URL:
        return dup_string (value);

    case CAL_COMPONENT_FIELD_HAS_ALARMS:
    case CAL_COMPONENT_FIELD_ICON:
    case CAL_COMPONENT_FIELD_COMPLETE:
    case CAL_COMPONENT_FIELD_RECURRING:
    case CAL_COMPONENT_FIELD_OVERDUE:
    case CAL_COMPONENT_FIELD_COLOR:
        return (void *) value;

    default:
        g_message ("calendar_model_duplicate_value(): Requested invalid column %d", col);
        return NULL;
    }
}

/* free_value handler for the calendar table model */
static void
calendar_model_free_value (ETableModel *etm, int col, void *value)
{
    g_return_if_fail (col >= 0 && col < CAL_COMPONENT_FIELD_NUM_FIELDS);

    switch (col) {
    case CAL_COMPONENT_FIELD_CATEGORIES:
        g_free (value);

    case CAL_COMPONENT_FIELD_CLASSIFICATION:
        return;

    case CAL_COMPONENT_FIELD_COMPLETED:
    case CAL_COMPONENT_FIELD_DTEND:
    case CAL_COMPONENT_FIELD_DTSTART:
    case CAL_COMPONENT_FIELD_DUE:
    case CAL_COMPONENT_FIELD_GEO:
    case CAL_COMPONENT_FIELD_PERCENT:
    case CAL_COMPONENT_FIELD_PRIORITY:
        g_free (value);

    case CAL_COMPONENT_FIELD_TRANSPARENCY:
        return;

    case CAL_COMPONENT_FIELD_URL:
        g_free (value);

    case CAL_COMPONENT_FIELD_HAS_ALARMS:
    case CAL_COMPONENT_FIELD_ICON:
    case CAL_COMPONENT_FIELD_COMPLETE:
    case CAL_COMPONENT_FIELD_RECURRING:
    case CAL_COMPONENT_FIELD_OVERDUE:
    case CAL_COMPONENT_FIELD_COLOR:
        return;

    default:
        g_message ("calendar_model_free_value(): Requested invalid column %d", col);
        return;
    }
}

/* Initializes a string value */
static char *
init_string (void)
{
    return g_strdup ("");
}

/* initialize_value handler for the calendar table model */
static void *
calendar_model_initialize_value (ETableModel *etm, int col)
{
    g_return_val_if_fail (col >= 0 && col < CAL_COMPONENT_FIELD_NUM_FIELDS, NULL);

    switch (col) {
    case CAL_COMPONENT_FIELD_CATEGORIES:
        return init_string ();

    case CAL_COMPONENT_FIELD_CLASSIFICATION:
        return NULL;

    case CAL_COMPONENT_FIELD_COMPLETED:
    case CAL_COMPONENT_FIELD_DTEND:
    case CAL_COMPONENT_FIELD_DTSTART:
    case CAL_COMPONENT_FIELD_DUE:
    case CAL_COMPONENT_FIELD_GEO:
    case CAL_COMPONENT_FIELD_PERCENT:
    case CAL_COMPONENT_FIELD_PRIORITY:
        return init_string ();

    case CAL_COMPONENT_FIELD_TRANSPARENCY:
        return NULL;

    case CAL_COMPONENT_FIELD_URL:
        return init_string ();

    case CAL_COMPONENT_FIELD_HAS_ALARMS:
    case CAL_COMPONENT_FIELD_ICON:
    case CAL_COMPONENT_FIELD_COMPLETE:
    case CAL_COMPONENT_FIELD_RECURRING:
    case CAL_COMPONENT_FIELD_OVERDUE:
    case CAL_COMPONENT_FIELD_COLOR:
        return NULL;

    default:
        g_message ("calendar_model_initialize_value(): Requested invalid column %d", col);
        return NULL;
    }
}

/* value_is_empty handler for the calendar model. This should return TRUE
   unless a significant value has been set. The 'click-to-add' feature
   checks all fields to see if any are not empty and if so it adds a new
   row, so we only want to return FALSE if we have a useful object. */
static gboolean
calendar_model_value_is_empty (ETableModel *etm, int col, const void *value)
{
    g_return_val_if_fail (col >= 0 && col < CAL_COMPONENT_FIELD_NUM_FIELDS, TRUE);

    switch (col) {
    case CAL_COMPONENT_FIELD_CATEGORIES:
    case CAL_COMPONENT_FIELD_CLASSIFICATION: /* actually goes here, not by itself */
    case CAL_COMPONENT_FIELD_COMPLETED:
    case CAL_COMPONENT_FIELD_DTEND:
    case CAL_COMPONENT_FIELD_DTSTART:
    case CAL_COMPONENT_FIELD_DUE:
    case CAL_COMPONENT_FIELD_GEO:
    case CAL_COMPONENT_FIELD_PERCENT:
    case CAL_COMPONENT_FIELD_PRIORITY:
    case CAL_COMPONENT_FIELD_TRANSPARENCY:
    case CAL_COMPONENT_FIELD_URL:
        return string_is_empty (value);

    case CAL_COMPONENT_FIELD_HAS_ALARMS:
    case CAL_COMPONENT_FIELD_ICON:
    case CAL_COMPONENT_FIELD_COMPLETE:
    case CAL_COMPONENT_FIELD_RECURRING:
    case CAL_COMPONENT_FIELD_OVERDUE:
    case CAL_COMPONENT_FIELD_COLOR:
        return TRUE;

    default:
        g_message ("calendar_model_value_is_empty(): Requested invalid column %d", col);
        return TRUE;
    }
}



/**
 * calendar_model_new:
 *
 * Creates a new calendar model.  It must be told about the calendar client
 * interface object it will monitor with calendar_model_set_cal_client().
 *
 * Return value: A newly-created calendar model.
 **/
CalendarModel *
calendar_model_new (void)
{
    return CALENDAR_MODEL (gtk_type_new (TYPE_CALENDAR_MODEL));
}


/* Callback used when a calendar is loaded into the server */
static void
cal_loaded_cb (CalClient *client,
           CalClientLoadStatus status,
           CalendarModel *model)
{
    g_return_if_fail (IS_CALENDAR_MODEL (model));

    e_table_model_pre_change (E_TABLE_MODEL (model));
    load_objects (model);
    e_table_model_changed (E_TABLE_MODEL (model));
}


/* Removes an object from the model and updates all the indices that follow.
 * Returns the index of the object that was removed, or -1 if no object with
 * such UID was found.
 */
static int
remove_object (CalendarModel *model, const char *uid)
{
    CalendarModelPrivate *priv;
    int *idx;
    CalComponent *orig_comp;
    int i;
    int n;

    priv = model->priv;

    /* Find the index of the object to be removed */

    idx = g_hash_table_lookup (priv->uid_index_hash, uid);
    if (!idx)
        return -1;

    orig_comp = g_array_index (priv->objects, CalComponent *, *idx);
    g_assert (orig_comp != NULL);

    /* Decrease the indices of all the objects that follow in the array */

    for (i = *idx + 1; i < priv->objects->len; i++) {
        CalComponent *comp;
        int *comp_idx;
        const char *comp_uid;

        comp = g_array_index (priv->objects, CalComponent *, i);
        g_assert (comp != NULL);

        cal_component_get_uid (comp, &comp_uid);

        comp_idx = g_hash_table_lookup (priv->uid_index_hash, comp_uid);
        g_assert (comp_idx != NULL);

        (*comp_idx)--;
        g_assert (*comp_idx >= 0);
    }

    /* Remove this object from the array and hash */

    g_hash_table_remove (priv->uid_index_hash, uid);
    g_array_remove_index (priv->objects, *idx);

    gtk_object_unref (GTK_OBJECT (orig_comp));

    n = *idx;
    g_free (idx);

    return n;
}

/* Callback used when an object is updated in the server */
static void
obj_updated_cb (CalClient *client, const char *uid, gpointer data)
{
    CalendarModel *model;
    CalendarModelPrivate *priv;
    int orig_idx;
    CalComponent *new_comp;
    const char *new_comp_uid;
    int *new_idx;
    CalClientGetStatus status;
    gboolean added;

    model = CALENDAR_MODEL (data);
    priv = model->priv;

    orig_idx = remove_object (model, uid);

    status = cal_client_get_object (priv->client, uid, &new_comp);

    added = FALSE;

    switch (status) {
    case CAL_CLIENT_GET_SUCCESS:
        cal_component_get_uid (new_comp, &new_comp_uid);

        if (orig_idx == -1) {
            /* The object not in the model originally, so we just append it */

            g_array_append_val (priv->objects, new_comp);

            new_idx = g_new (int, 1);
            *new_idx = priv->objects->len - 1;

            g_hash_table_insert (priv->uid_index_hash, (char *) new_comp_uid, new_idx);
        } else {
            int i;

            /* Insert the new version of the object in its old position */

            g_array_insert_val (priv->objects, orig_idx, new_comp);

            new_idx = g_new (int, 1);
            *new_idx = orig_idx;
            g_hash_table_insert (priv->uid_index_hash, (char *) new_comp_uid, new_idx);

            /* Increase the indices of all subsequent objects */

            for (i = orig_idx + 1; i < priv->objects->len; i++) {
                CalComponent *comp;
                int *comp_idx;
                const char *comp_uid;

                comp = g_array_index (priv->objects, CalComponent *, i);
                g_assert (comp != NULL);

                cal_component_get_uid (comp, &comp_uid);

                comp_idx = g_hash_table_lookup (priv->uid_index_hash, comp_uid);
                g_assert (comp_idx != NULL);

                (*comp_idx)++;
            }
        }

        e_table_model_row_changed (E_TABLE_MODEL (model), *new_idx);
        break;

    case CAL_CLIENT_GET_NOT_FOUND:
        /* Nothing; the object may have been removed from the server.  We just
         * notify that the old object was deleted.
         */
        if (orig_idx != -1)
            e_table_model_row_deleted (E_TABLE_MODEL (model), orig_idx);

        break;

    case CAL_CLIENT_GET_SYNTAX_ERROR:
        g_message ("obj_updated_cb(): Syntax error when getting object `%s'", uid);

        /* Same notification as above */
        if (orig_idx != -1)
            e_table_model_row_deleted (E_TABLE_MODEL (model), orig_idx);

        break;

    default:
        g_assert_not_reached ();
    }
}

/* Callback used when an object is removed in the server */
static void
obj_removed_cb (CalClient *client, const char *uid, gpointer data)
{
    CalendarModel *model;
    int idx;

    model = CALENDAR_MODEL (data);

    idx = remove_object (model, uid);

    if (idx != -1)
        e_table_model_row_deleted (E_TABLE_MODEL (model), idx);
}

/* Loads the required objects from the calendar client */
static void
load_objects (CalendarModel *model)
{
    CalendarModelPrivate *priv;
    GList *uids;
    GList *l;

    priv = model->priv;

    uids = cal_client_get_uids (priv->client, priv->type);

    for (l = uids; l; l = l->next) {
        char *uid;
        CalComponent *comp;
        const char *comp_uid;
        CalClientGetStatus status;
        int *idx;

        uid = l->data;
        status = cal_client_get_object (priv->client, uid, &comp);

        switch (status) {
        case CAL_CLIENT_GET_SUCCESS:
            break;

        case CAL_CLIENT_GET_NOT_FOUND:
            /* Nothing; the object may have been removed from the server */
            continue;

        case CAL_CLIENT_GET_SYNTAX_ERROR:
            g_message ("load_objects(): Syntax error when getting object `%s'", uid);
            continue;

        default:
            g_assert_not_reached ();
        }

        idx = g_new (int, 1);

        g_array_append_val (priv->objects, comp);
        *idx = priv->objects->len - 1;

        cal_component_get_uid (comp, &comp_uid);
        g_hash_table_insert (priv->uid_index_hash, (char *) comp_uid, idx);
    }

    cal_obj_uid_list_free (uids);
}

/**
 * calendar_model_get_cal_client:
 * @model: A calendar model.
 * 
 * Queries the calendar client interface object that a calendar model is using.
 * 
 * Return value: A calendar client interface object.
 **/
CalClient *
calendar_model_get_cal_client (CalendarModel *model)
{
    CalendarModelPrivate *priv;

    g_return_val_if_fail (model != NULL, NULL);
    g_return_val_if_fail (IS_CALENDAR_MODEL (model), NULL);

    priv = model->priv;

    return priv->client;
}


/**
 * calendar_model_set_cal_client:
 * @model: A calendar model.
 * @client: A calendar client interface object.
 * @type: Type of objects to present.
 *
 * Sets the calendar client interface object that a calendar model will monitor.
 * It also sets the types of objects this model will present to an #ETable.
 **/
void
calendar_model_set_cal_client (CalendarModel *model, CalClient *client, CalObjType type)
{
    CalendarModelPrivate *priv;

    g_return_if_fail (model != NULL);
    g_return_if_fail (IS_CALENDAR_MODEL (model));

    if (client)
        g_return_if_fail (IS_CAL_CLIENT (client));

    priv = model->priv;

    if (priv->client == client && priv->type == type)
        return;

    e_table_model_pre_change (E_TABLE_MODEL(model));

    if (client)
        gtk_object_ref (GTK_OBJECT (client));

    if (priv->client) {
        gtk_signal_disconnect_by_data (GTK_OBJECT (priv->client), model);
        gtk_object_unref (GTK_OBJECT (priv->client));
    }

    free_objects (model);

    priv->client = client;
    priv->type = type;

    if (priv->client) {
        gtk_signal_connect (GTK_OBJECT (priv->client), "cal_loaded",
                    GTK_SIGNAL_FUNC (cal_loaded_cb), model);
        gtk_signal_connect (GTK_OBJECT (priv->client), "obj_updated",
                    GTK_SIGNAL_FUNC (obj_updated_cb), model);
        gtk_signal_connect (GTK_OBJECT (priv->client), "obj_removed",
                    GTK_SIGNAL_FUNC (obj_removed_cb), model);

        load_objects (model);
    }

    e_table_model_changed (E_TABLE_MODEL (model));
}


void
calendar_model_delete_task (CalendarModel *model,
                gint row)
{
    CalendarModelPrivate *priv;
    CalComponent *comp;
    const char *uid;

    g_return_if_fail (model != NULL);
    g_return_if_fail (IS_CALENDAR_MODEL (model));

    priv = model->priv;

    g_return_if_fail (row >= 0 && row < priv->objects->len);

    comp = g_array_index (priv->objects, CalComponent *, row);
    g_assert (comp != NULL);

    cal_component_get_uid (comp, &uid);

    if (!cal_client_remove_object (priv->client, uid))
        g_message ("calendar_model_delete_task(): Could not remove the object!");
}


void
calendar_model_mark_task_complete (CalendarModel *model,
                   gint row)
{
    CalendarModelPrivate *priv;
    CalComponent *comp;
    int percent;
    struct icaltimetype itt;

    g_return_if_fail (model != NULL);
    g_return_if_fail (IS_CALENDAR_MODEL (model));

    priv = model->priv;

    g_return_if_fail (row >= 0 && row < priv->objects->len);

    comp = g_array_index (priv->objects, CalComponent *, row);
    g_assert (comp != NULL);

    percent = 100;
    cal_component_set_percent (comp, &percent);

    itt = icaltimetype_from_timet (time (NULL), FALSE);
    cal_component_set_completed (comp, &itt);

    if (!cal_client_update_object (priv->client, comp))
        g_message ("calendar_model_mark_task_complete(): Could not update the object!");
}


/* Frees the objects stored in the calendar model */
CalComponent *
calendar_model_get_cal_object (CalendarModel *model,
                   gint       row)
{
    CalendarModelPrivate *priv;

    g_return_val_if_fail (model != NULL, NULL);
    g_return_val_if_fail (IS_CALENDAR_MODEL (model), NULL);

    priv = model->priv;

    g_return_val_if_fail (row >= 0 && row < priv->objects->len, NULL);

    return g_array_index (priv->objects, CalComponent *, row);
}