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 Ximian, Inc.
 * Copyright (C) 2000 Ximian, Inc.
 *
 * Authors: Federico Mena-Quintero <federico@ximian.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.
 */

#include <config.h>

#include <math.h>
#include <sys/types.h>

#include <ctype.h>

#include <libgnomeui/gnome-messagebox.h>
#include <libgnomeui/gnome-stock.h>
#include <libgnome/gnome-i18n.h>
#include <gal/widgets/e-unicode.h>
#include <e-util/e-time-utils.h>
#include <cal-util/timeutil.h>
#include "calendar-commands.h"
#include "calendar-config.h"
#include "calendar-model.h"


/* Private part of the ECalendarModel structure */
struct _CalendarModelPrivate {
    /* 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;

    /* Type of components to create when using click-to-add in the table */
    CalComponentVType new_comp_vtype;

    /* Whether we display dates in 24-hour format. */
    gboolean use_24_hour_format;

    /* The default category to use when creating new tasks, e.g. when the
       filter is set to a certain category we use that category when
       creating a new task. */
    gchar *default_category;

    /* A balanced tree of the categories used by all the tasks/events. */
    GTree *categories;

    /* The current timezone. */
    icaltimezone *zone;
};

enum {
    CATEGORIES_CHANGED,
    LAST_SIGNAL
};

static gint calendar_model_signals [LAST_SIGNAL] = { 0 };



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);
static char * calendar_model_value_to_string (ETableModel *etm, int col, const void *value);
static void load_objects (CalendarModel *model);
static int remove_object (CalendarModel *model, const char *uid);
static void ensure_task_complete (CalComponent *comp,
                  time_t completed_date);
static void ensure_task_not_complete (CalComponent *comp);
static void calendar_model_collect_all_categories (CalendarModel *model);
static gboolean calendar_model_collect_categories   (CalendarModel  *model,
                             CalComponent   *comp);

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);

    calendar_model_signals [CATEGORIES_CHANGED] =
        gtk_signal_new ("categories-changed",
                GTK_RUN_LAST, object_class->type,
                GTK_SIGNAL_OFFSET (CalendarModelClass,
                           categories_changed),
                gtk_signal_default_marshaller,
                GTK_TYPE_NONE, 0);

    gtk_object_class_add_signals (object_class, calendar_model_signals,
                      LAST_SIGNAL);

    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;
    etm_class->value_to_string = calendar_model_value_to_string;

    class->categories_changed = NULL;
}

/* 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);
    priv->new_comp_vtype = CAL_COMPONENT_EVENT;
    priv->use_24_hour_format = TRUE;

    priv->categories = g_tree_new ((GCompareFunc)strcmp);

    priv->zone = NULL;
}

/* 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;

    g_free (priv->default_category);

    /* We only need to free the first argument, the key, so g_free will do.
     */
    g_tree_traverse (priv->categories, (GTraverseFunc) g_free,
             G_PRE_ORDER, NULL);
    g_tree_destroy (priv->categories);

    /* 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. If show_midnight is
   FALSE, and the time is midnight, then we just show the date. */
static char*
get_time_t (CalendarModel *model, time_t *t, gboolean show_midnight)
{
    static char buffer[64];
    struct tm tmp_tm;
    struct icaltimetype tt;

    if (*t <= 0) {
        buffer[0] = '\0';
    } else {
        /* Note that although the property may be in a different
           timezone, we convert it to the current timezone to display
           it in the table. If the user actually edits the value,
           it will be set to the current timezone. See set_datetime. */
        tt = icaltime_from_timet_with_zone (*t, FALSE,
                            model->priv->zone);
        tmp_tm.tm_year = tt.year - 1900;
        tmp_tm.tm_mon = tt.month - 1;
        tmp_tm.tm_mday = tt.day;
        tmp_tm.tm_hour = tt.hour;
        tmp_tm.tm_min = tt.minute;
        tmp_tm.tm_sec = tt.second;
        tmp_tm.tm_isdst = -1;

        tmp_tm.tm_wday = time_day_of_week (tt.day, tt.month - 1,
                           tt.year);

        e_time_format_date_and_time (&tmp_tm,
                         model->priv->use_24_hour_format,
                         show_midnight, FALSE,
                         buffer, sizeof (buffer));
    }

    return buffer;
}

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

    cal_component_get_categories (comp, &categories);

    return categories ? (char*) categories : "";
}

/* 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 "";
    }
}

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

    cal_component_get_completed (comp, &completed);

    if (!completed)
        t = 0;
    else {
        /* Note that COMPLETED is stored in UTC, though we show it in
           the current timezone. */
        t = icaltime_as_timet_with_zone (*completed, icaltimezone_get_utc_timezone ());
        cal_component_free_icaltimetype (completed);
    }

    return get_time_t (model, &t, TRUE);
}

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

    if (!dt.value)
        t = 0;
    else {
        CalClientGetStatus status;
        icaltimezone *zone;

        /* FIXME: TIMEZONES: Handle error. */
        status = cal_client_get_timezone (model->priv->client, dt.tzid,
                          &zone);
        t = icaltime_as_timet_with_zone (*dt.value, zone);
    }

    cal_component_free_datetime (&dt);

    return get_time_t (model, &t, TRUE);
}

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

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

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

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

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

    cal_component_get_due (comp, &dt);
    return get_and_free_datetime (model, 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;
    char *retval;

    cal_component_get_priority (comp, &priority);

    if (!priority || *priority == 0)
        retval = "";
    else if (*priority <= 4)
        retval = _("High");
    else if (*priority == 5)
        retval = _("Normal");
    else
        retval = _("Low");

    if (priority)
        cal_component_free_priority (priority);

    return retval;
}

/* 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:
    case CAL_COMPONENT_TRANSP_UNKNOWN:
        return "";

    case CAL_COMPONENT_TRANSP_TRANSPARENT:
        return _("Transparent");

    case CAL_COMPONENT_TRANSP_OPAQUE:
        return _("Opaque");

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

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

    if (retval)
        cal_component_free_icaltimetype (t);

    return retval;
}

/* Returns whether a component is overdue.  Sigh, this is very similar to
 * get_color() below.
 */
static gboolean
is_overdue (CalendarModel *model, 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 now_tt;
        CalClientGetStatus status;
        icaltimezone *zone;

        /* Second, is it already completed? */

        if (is_complete (comp)) {
            retval = FALSE;
            goto out;
        }

        /* Third, are we overdue as of right now? */

        /* Get the current time in the same timezone as the DUE date.*/
        /* FIXME: TIMEZONES: Handle error. */
        status = cal_client_get_timezone (model->priv->client, dt.tzid,
                          &zone);
        now_tt = icaltime_current_time_with_zone (zone);

        if (icaltime_compare (*dt.value, now_tt) <= 0)
            retval = TRUE;
        else
            retval = FALSE;
    }

 out:

    cal_component_free_datetime (&dt);

    return retval;
}

/* Computes the color to be used to display a component */
static const char *
get_color (CalendarModel *model, CalComponent *comp)
{
    CalComponentDateTime dt;
    const char *retval;

    cal_component_get_due (comp, &dt);

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

    if (!dt.value)
        retval = NULL;
    else {
        struct icaltimetype now_tt;
        CalClientGetStatus status;
        icaltimezone *zone;

        /* Second, is it already completed? */

        if (is_complete (comp)) {
            retval = NULL;
            goto out;
        }

        /* Third, is it due today? */

        /* Get the current time in the same timezone as the DUE date.*/
        /* FIXME: TIMEZONES: Handle error. */
        status = cal_client_get_timezone (model->priv->client, dt.tzid,
                          &zone);
        now_tt = icaltime_current_time_with_zone (zone);

        if (icaltime_compare_date_only (*dt.value, now_tt) == 0) {
            retval = calendar_config_get_tasks_due_today_color ();
            goto out;
        }

        /* Fourth, are we overdue as of right now?  We use <= in the
         * comparison below so that the table entries change color
         * immediately.
         */

        if (icaltime_compare (*dt.value, now_tt) <= 0)
            retval = calendar_config_get_tasks_overdue_color ();
        else
            retval = NULL;
    }

 out:

    cal_component_free_datetime (&dt);

    return retval;
}

static void *
get_status (CalComponent *comp)
{
    icalproperty_status status;

    cal_component_get_status (comp, &status);

    switch (status) {
    case ICAL_STATUS_NONE:
        return "";

    case ICAL_STATUS_NEEDSACTION:
        return _("Not Started");

    case ICAL_STATUS_INPROCESS:
        return _("In Progress");

    case ICAL_STATUS_COMPLETED:
        return _("Completed");

    case ICAL_STATUS_CANCELLED:
        return _("Cancelled");

    default:
        g_assert_not_reached ();
        return NULL;
    }
}

/* 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);

#if 0
    g_print ("In calendar_model_value_at: %i\n", col);
#endif

    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 (model, comp);

    case CAL_COMPONENT_FIELD_DTEND:
        return get_dtend (model, comp);

    case CAL_COMPONENT_FIELD_DTSTART:
        return get_dtstart (model, comp);

    case CAL_COMPONENT_FIELD_DUE:
        return get_due (model, 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 (cal_component_has_alarms (comp));

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

            ical_comp = cal_component_get_icalcomponent (comp);
            if (icalcomponent_get_first_property (ical_comp,
                                  ICAL_ATTENDEE_PROPERTY) != NULL)
            {
                return GINT_TO_POINTER (2); /* Task-assigned */
            }
            else {
                return GINT_TO_POINTER (0);
            }
        }
    case CAL_COMPONENT_FIELD_COMPLETE:
        return GINT_TO_POINTER (is_complete (comp));

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

    case CAL_COMPONENT_FIELD_OVERDUE:
        return GINT_TO_POINTER (is_overdue (model, comp));

    case CAL_COMPONENT_FIELD_COLOR:
        return (void *) get_color (model, comp);

    case CAL_COMPONENT_FIELD_STATUS:
        return get_status (comp);

    case CAL_COMPONENT_FIELD_COMPONENT:
        return comp;

    default:
        g_message ("calendar_model_value_at(): Requested invalid column %d", col);
        g_assert_not_reached ();
        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 (CalendarModel *model)
{
    GtkWidget *dialog;
    char buffer[64], message[256], *format;
    time_t t;
    struct tm *tmp_tm;

    t = time (NULL);
    /* We are only using this as an example, so the timezone doesn't
       matter. */
    tmp_tm = localtime (&t);

    if (model->priv->use_24_hour_format)
        /* strftime format of a weekday, a date and a time, 24-hour. */
        format = _("%a %m/%d/%Y %H:%M:%S");
    else
        /* strftime format of a weekday, a date and a time, 12-hour. */
        format = _("%a %m/%d/%Y %I:%M:%S %p");

    strftime (buffer, sizeof (buffer), format, 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);
}


/* FIXME: We won't need this eventually, since the user won't be allowed to
 * edit the field.
 */
static void
show_classification_warning (void)
{
    GtkWidget *dialog;

    dialog = gnome_message_box_new (_("The classification must be 'Public', 'Private', 'Confidential' or 'None'"),
                    GNOME_MESSAGE_BOX_ERROR,
                    GNOME_STOCK_BUTTON_OK, NULL);
    gtk_widget_show (dialog);
}


static void
set_classification (CalComponent *comp,
            const char *value)
{
    CalComponentClassification classif;

    /* An empty string is the same as 'None'. */
    if (!value[0] || !g_strcasecmp (value, _("None")))
        classif = CAL_COMPONENT_CLASS_NONE;
    else if (!g_strcasecmp (value, _("Public")))
        classif = CAL_COMPONENT_CLASS_PUBLIC;
    else if (!g_strcasecmp (value, _("Private")))
        classif = CAL_COMPONENT_CLASS_PRIVATE;
    else if (!g_strcasecmp (value, _("Confidential")))
        classif = CAL_COMPONENT_CLASS_CONFIDENTIAL;
    else {
        show_classification_warning ();
        return;
    }

    cal_component_set_classification (comp, classif);
}


/* Called to set the "Date Completed" field. We also need to update the
   Status and Percent fields to make sure they match. */
static void
set_completed (CalendarModel *model, CalComponent *comp, const char *value)
{
    ETimeParseStatus status;
    struct tm tmp_tm;
    time_t t;

    status = e_time_parse_date_and_time (value, &tmp_tm);

    if (status == E_TIME_PARSE_INVALID) {
        show_date_warning (model);
    } else if (status == E_TIME_PARSE_NONE) {
        ensure_task_not_complete (comp);
    } else {
        struct icaltimetype itt = icaltime_null_time ();

        itt.year = tmp_tm.tm_year + 1900;
        itt.month = tmp_tm.tm_mon + 1;
        itt.day = tmp_tm.tm_mday;
        itt.hour = tmp_tm.tm_hour;
        itt.minute = tmp_tm.tm_min;
        itt.second = tmp_tm.tm_sec;

        /* We assume that COMPLETED is entered in the current timezone,
           even though it gets stored in UTC. */
        t = icaltime_as_timet_with_zone (itt, model->priv->zone);

        ensure_task_complete (comp, t);
    }
}

/* Sets a CalComponentDateTime value */
static void
set_datetime (CalendarModel *model, CalComponent *comp, const char *value,
          void (* set_func) (CalComponent *comp, CalComponentDateTime *dt))
{
    ETimeParseStatus status;
    struct tm tmp_tm;

    status = e_time_parse_date_and_time (value, &tmp_tm);

    if (status == E_TIME_PARSE_INVALID) {
        show_date_warning (model);
    } else if (status == E_TIME_PARSE_NONE) {
        (* set_func) (comp, NULL);
    } else {
        CalComponentDateTime dt;
        struct icaltimetype itt = icaltime_null_time ();

        itt.year = tmp_tm.tm_year + 1900;
        itt.month = tmp_tm.tm_mon + 1;
        itt.day = tmp_tm.tm_mday;
        itt.hour = tmp_tm.tm_hour;
        itt.minute = tmp_tm.tm_min;
        itt.second = tmp_tm.tm_sec;

        dt.value = &itt;
        /* We assume it is being set to the current timezone. */
        dt.tzid = icaltimezone_get_tzid (model->priv->zone);

        (* 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);
        ensure_task_not_complete (comp);
        return;
    }

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

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

    cal_component_set_percent (comp, &percent);

    if (percent == 100)
        ensure_task_complete (comp, -1);
    else
        ensure_task_not_complete (comp);
}

/* FIXME: We won't need this eventually, since the user won't be allowed to
 * edit the field.
 */
static void
show_priority_warning (void)
{
    GtkWidget *dialog;

    dialog = gnome_message_box_new (_("The priority must be 'High', 'Normal', 'Low' or 'Undefined'."),
                    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 priority;

    /* An empty string is the same as 'None'. */
    if (!value[0] || !g_strcasecmp (value, _("Undefined")))
        priority = 0;
    else if (!g_strcasecmp (value, _("High")))
        priority = 3;
    else if (!g_strcasecmp (value, _("Normal")))
        priority = 5;
    else if (!g_strcasecmp (value, _("Low")))
        priority = 7;
    else {
        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);
}

/* FIXME: We won't need this eventually, since the user won't be allowed to
 * edit the field.
 */
static void
show_transparency_warning (void)
{
    GtkWidget *dialog;

    dialog = gnome_message_box_new (_("The transparency must be 'Transparent', 'Opaque', or 'None'."),
                    GNOME_MESSAGE_BOX_ERROR,
                    GNOME_STOCK_BUTTON_OK, NULL);
    gtk_widget_show (dialog);
}

/* Sets the URI of a calendar component */
static void
set_transparency (CalComponent *comp, const char *value)
{
    CalComponentTransparency transp;

    g_print ("In calendar model set_transparency: %s\n", value);

    /* An empty string is the same as 'None'. */
    if (!value[0] || !g_strcasecmp (value, _("None")))
        transp = CAL_COMPONENT_TRANSP_NONE;
    else if (!g_strcasecmp (value, _("Transparent")))
        transp = CAL_COMPONENT_TRANSP_TRANSPARENT;
    else if (!g_strcasecmp (value, _("Opaque"))) {
        transp = CAL_COMPONENT_TRANSP_OPAQUE;
    } else {
        show_transparency_warning ();
        return;
    }

    g_print ("  transp: %i\n", transp);

    cal_component_set_transparency (comp, transp);
}

/* Sets the URI of a calendar component */
static void
set_url (CalComponent *comp, const char *value)
{
    g_print ("In calendar model set_url\n");

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

    cal_component_set_url (comp, value);
}

/* Called to set the checkbutton field which indicates whether a task is
   complete. */
static void
set_complete (CalComponent *comp, const void *value)
{
    gint state = GPOINTER_TO_INT (value);

    if (state) {
        ensure_task_complete (comp, -1);
    } else {
        ensure_task_not_complete (comp);
    }
}

/* Sets the status of a calendar component. */
static void
set_status (CalComponent *comp, const char *value)
{
    icalproperty_status status;
    int percent;

    g_print ("In calendar model set_status: %s\n", value);

    /* An empty string is the same as 'None'. */
    if (!value[0] || !g_strcasecmp (value, _("None")))
        status = ICAL_STATUS_NONE;
    else if (!g_strcasecmp (value, _("Not Started")))
        status = ICAL_STATUS_NEEDSACTION;
    else if (!g_strcasecmp (value, _("In Progress")))
        status = ICAL_STATUS_INPROCESS;
    else if (!g_strcasecmp (value, _("Completed")))
        status = ICAL_STATUS_COMPLETED;
    else if (!g_strcasecmp (value, _("Cancelled")))
        status = ICAL_STATUS_CANCELLED;
    else {
        g_warning ("Invalid status: %s\n", value);
        return;
    }

    cal_component_set_status (comp, status);

    if (status == ICAL_STATUS_NEEDSACTION) {
        percent = 0;
        cal_component_set_percent (comp, &percent);
        cal_component_set_completed (comp, NULL);
    } else if (status == ICAL_STATUS_COMPLETED) {
        ensure_task_complete (comp, -1);
    }
}

/* 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);

#if 1
    g_print ("In calendar_model_set_value_at: %i\n", col);
#endif

    switch (col) {
    case CAL_COMPONENT_FIELD_CATEGORIES:
        set_categories (comp, value);
        if (calendar_model_collect_categories (model, comp)) {
            gtk_signal_emit (GTK_OBJECT (model),
                     calendar_model_signals [CATEGORIES_CHANGED]);
        }
        break;

    case CAL_COMPONENT_FIELD_CLASSIFICATION:
        set_classification (comp, value);
        break;

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

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

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

    case CAL_COMPONENT_FIELD_DUE:
        set_datetime (model, 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;

    case CAL_COMPONENT_FIELD_TRANSPARENCY:
        set_transparency (comp, value);
        break;

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

    case CAL_COMPONENT_FIELD_COMPLETE:
        set_complete (comp, value);
        break;

    case CAL_COMPONENT_FIELD_STATUS:
        set_status (comp, value);
        break;

    default:
        g_message ("calendar_model_set_value_at(): Requested invalid column %d", col);
        g_assert_not_reached ();
        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_CLASSIFICATION:
    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_TRANSPARENCY:
    case CAL_COMPONENT_FIELD_URL:
    case CAL_COMPONENT_FIELD_COMPLETE:
    case CAL_COMPONENT_FIELD_STATUS:
        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;

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

    /* 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, priv->new_comp_vtype);

    set_categories (comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_CATEGORIES, row));
    set_classification (comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_CLASSIFICATION, row));
    set_completed (model, comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_COMPLETED, row));
    /* FIXME: Need to reset dtstart if dtend happens before it */
    set_datetime (model, comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_DTEND, row), cal_component_set_dtend);
    /* FIXME: Need to reset dtend if dtstart happens after it */
    set_datetime (model, comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_DTSTART, row), cal_component_set_dtstart);
    set_datetime (model, comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_DUE, row), cal_component_set_due);
    set_geo (comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_GEO, row));
    set_percent (comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_PERCENT, row));
    set_priority (comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_PRIORITY, row));
    set_summary (comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_SUMMARY, row));
    set_transparency (comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_TRANSPARENCY, row));
    set_url (comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_URL, row));
    set_complete (comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_COMPLETE, row));
    set_status (comp, e_table_model_value_at(source, CAL_COMPONENT_FIELD_STATUS, row));

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

    gtk_object_unref (GTK_OBJECT (comp));
}

/* 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:
    case CAL_COMPONENT_FIELD_CLASSIFICATION:
    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_TRANSPARENCY:
    case CAL_COMPONENT_FIELD_URL:
    case CAL_COMPONENT_FIELD_STATUS:
        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;

    case CAL_COMPONENT_FIELD_COMPONENT: {
        CalComponent *comp;

        comp = CAL_COMPONENT (value);
        gtk_object_ref (GTK_OBJECT (comp));
        return comp;
    }

    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);
        break;

    case CAL_COMPONENT_FIELD_CLASSIFICATION:
        break;

    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_STATUS:
        g_free (value);
        break;

    case CAL_COMPONENT_FIELD_TRANSPARENCY:
        break;

    case CAL_COMPONENT_FIELD_URL:
        g_free (value);
        break;

    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:
        break;

    case CAL_COMPONENT_FIELD_COMPONENT:
        gtk_object_unref (GTK_OBJECT (value));
        break;

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

/* 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)
{
    CalendarModel *model;

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

    model = CALENDAR_MODEL (etm);

    switch (col) {
    case CAL_COMPONENT_FIELD_CATEGORIES:
        return g_strdup (model->priv->default_category ? model->priv->default_category : "");

    case CAL_COMPONENT_FIELD_CLASSIFICATION:
    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_TRANSPARENCY:
    case CAL_COMPONENT_FIELD_URL:
    case CAL_COMPONENT_FIELD_STATUS:
        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:
    case CAL_COMPONENT_FIELD_COMPONENT:
        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_SUMMARY:
    case CAL_COMPONENT_FIELD_TRANSPARENCY:
    case CAL_COMPONENT_FIELD_URL:
    case CAL_COMPONENT_FIELD_STATUS:
        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:
    case CAL_COMPONENT_FIELD_COMPONENT:
        return TRUE;

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

static char *
calendar_model_value_to_string (ETableModel *etm, int col, const void *value)
{
    g_return_val_if_fail (col >= 0 && col < CAL_COMPONENT_FIELD_NUM_FIELDS, NULL);

    switch (col) {
    case CAL_COMPONENT_FIELD_CATEGORIES:
    case CAL_COMPONENT_FIELD_CLASSIFICATION:
    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_TRANSPARENCY:
    case CAL_COMPONENT_FIELD_URL:
    case CAL_COMPONENT_FIELD_STATUS:
        return e_utf8_from_locale_string (value);

    case CAL_COMPONENT_FIELD_ICON:
        if ((int)value == 0)
            return e_utf8_from_locale_string (_("Normal"));
        else if ((int)value == 1)
            return e_utf8_from_locale_string (_("Recurring"));
        else
            return e_utf8_from_locale_string (_("Assigned"));

    case CAL_COMPONENT_FIELD_HAS_ALARMS:
    case CAL_COMPONENT_FIELD_COMPLETE:
    case CAL_COMPONENT_FIELD_RECURRING:
    case CAL_COMPONENT_FIELD_OVERDUE:
        return e_utf8_from_locale_string (value ? _("Yes") : _("No"));

    case CAL_COMPONENT_FIELD_COLOR:
        return NULL;

    case CAL_COMPONENT_FIELD_COMPONENT:
        return NULL;

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



/**
 * 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 opened into the server */
static void
cal_opened_cb (CalClient *client, CalClientOpenStatus status, gpointer data)
{
    CalendarModel *model;

    model = CALENDAR_MODEL (data);

    e_table_model_pre_change (E_TABLE_MODEL (model));

    if (status == CAL_CLIENT_OPEN_SUCCESS) {
        load_objects (model);
        calendar_model_collect_all_categories (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;
}

/* Returns whether a component's type matches the types we support */
static gboolean
matches_type (CalObjType type, CalComponentVType vtype)
{
    return ((vtype == CAL_COMPONENT_EVENT && (type & CALOBJ_TYPE_EVENT))
        || (vtype == CAL_COMPONENT_TODO && (type & CALOBJ_TYPE_TODO))
        || (vtype == CAL_COMPONENT_JOURNAL && (type & CALOBJ_TYPE_JOURNAL)));
}

/* 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;
    CalComponentVType new_comp_vtype;
    const char *new_comp_uid;
    int *new_idx;
    CalClientGetStatus status;

    g_print ("In calendar model obj_updated_cb\n");

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

    orig_idx = remove_object (model, uid);

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

    switch (status) {
    case CAL_CLIENT_GET_SUCCESS:
        /* Check if we are interested in this type of object */

        new_comp_vtype = cal_component_get_vtype (new_comp);
        if (!matches_type (priv->type, new_comp_vtype)) {
            gtk_object_unref (GTK_OBJECT (new_comp));
            break;
        }

        /* Insert the object into the model */

        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);
            e_table_model_row_inserted (E_TABLE_MODEL (model), *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);
        }

        /* See if we need to add any categories. Note that old
           categories won't be removed, but I don't think that matters
           too much here. */
        if (calendar_model_collect_categories (model, new_comp)) {
            gtk_signal_emit (GTK_OBJECT (model),
                     calendar_model_signals [CATEGORIES_CHANGED]);
        }

        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 ();
    }

    g_print ("Out calendar model obj_updated_cb\n");
}

/* 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;

    g_assert (cal_client_get_load_state (priv->client) == CAL_CLIENT_LOAD_LOADED);

    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;
        CalComponentVType comp_vtype;
        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 ();
        }

        /* Check if we are interested in this type of object */

        comp_vtype = cal_component_get_vtype (comp);
        if (!matches_type (priv->type, comp_vtype)) {
            gtk_object_unref (GTK_OBJECT (comp));
            continue;
        }

        /* Insert the object into the model */

        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), "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);

        if (cal_client_get_load_state (priv->client) != CAL_CLIENT_LOAD_LOADED)
            gtk_signal_connect (GTK_OBJECT (priv->client), "cal_opened",
                        GTK_SIGNAL_FUNC (cal_opened_cb), model);
        else
            load_objects (model);
    }

    e_table_model_changed (E_TABLE_MODEL (model));
}


/**
 * calendar_model_set_new_comp_vtype:
 * @model: A calendar model.
 * @vtype: Type of calendar components to create.
 *
 * Sets the type of calendar components that will be created by a calendar table
 * model when the click-to-add functionality of the table is used.
 **/
void
calendar_model_set_new_comp_vtype (CalendarModel *model, CalComponentVType vtype)
{
    CalendarModelPrivate *priv;

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

    priv = model->priv;
    priv->new_comp_vtype = vtype;
}

/**
 * calendar_model_get_new_comp_vtype:
 * @model: A calendar model.
 *
 * Queries the type of calendar components that are created by a calendar table
 * model when using the click-to-add functionality in a table.
 *
 * Return value: Type of components that are created.
 **/
CalComponentVType
calendar_model_get_new_comp_vtype (CalendarModel *model)
{
    CalendarModelPrivate *priv;

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

    priv = model->priv;
    return priv->new_comp_vtype;
}


void
calendar_model_mark_task_complete (CalendarModel *model,
                   gint row)
{
    CalendarModelPrivate *priv;
    CalComponent *comp;

    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);

    ensure_task_complete (comp, -1);

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


/**
 * calendar_model_get_component:
 * @model: A calendar model.
 * @row: Row number of sought calendar component.
 *
 * Queries a calendar component from a calendar model based on its row number.
 *
 * Return value: The sought calendar component.
 **/
CalComponent *
calendar_model_get_component (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);
}


/* This makes sure a task is marked as complete.
   It makes sure the "Date Completed" property is set. If the completed_date
   is not -1, then that is used, otherwise if the "Date Completed" property
   is not already set it is set to the current time.
   It makes sure the percent is set to 100, and that the status is "Completed".
   Note that this doesn't update the component on the client. */
static void
ensure_task_complete (CalComponent *comp,
              time_t completed_date)
{
    struct icaltimetype *old_completed = NULL;
    int *old_percent, new_percent;
    icalproperty_status status;
    gboolean set_completed = TRUE;

    /* Date Completed. */
    if (completed_date == -1) {
        cal_component_get_completed (comp, &old_completed);

        if (old_completed) {
            cal_component_free_icaltimetype (old_completed);
            set_completed = FALSE;
        } else {
            completed_date = time (NULL);
        }
    }

    if (set_completed) {
        icaltimezone *utc_zone;
        struct icaltimetype new_completed;

        /* COMPLETED is stored in UTC. */
        utc_zone = icaltimezone_get_utc_timezone ();
        new_completed = icaltime_from_timet_with_zone (completed_date,
                                   FALSE,
                                   utc_zone);
        cal_component_set_completed (comp, &new_completed);
    }

    /* Percent. */
    cal_component_get_percent (comp, &old_percent);
    if (!old_percent || *old_percent != 100) {
        new_percent = 100;
        cal_component_set_percent (comp, &new_percent);
    }
    if (old_percent)
        cal_component_free_percent (old_percent);

    /* Status. */
    cal_component_get_status (comp, &status);
    if (status != ICAL_STATUS_COMPLETED) {
        cal_component_set_status (comp, ICAL_STATUS_COMPLETED);
    }
}


/* This makes sure a task is marked as incomplete. It clears the
   "Date Completed" property. If the percent is set to 100 it removes it,
   and if the status is "Completed" it sets it to "Needs Action".
   Note that this doesn't update the component on the client. */
static void
ensure_task_not_complete (CalComponent *comp)
{
    icalproperty_status old_status;
    int *old_percent;

    /* Date Completed. */
    cal_component_set_completed (comp, NULL);

    /* Percent. */
    cal_component_get_percent (comp, &old_percent);
    if (old_percent && *old_percent == 100)
        cal_component_set_percent (comp, NULL);
    if (old_percent)
        cal_component_free_percent (old_percent);

    /* Status. */
    cal_component_get_status (comp, &old_status);
    if (old_status == ICAL_STATUS_COMPLETED)
        cal_component_set_status (comp, ICAL_STATUS_NEEDSACTION);
}


/* Whether we use 24 hour format to display the times. */
gboolean
calendar_model_get_use_24_hour_format (CalendarModel *model)
{
    g_return_val_if_fail (IS_CALENDAR_MODEL (model), TRUE);

    return model->priv->use_24_hour_format;
}


void
calendar_model_set_use_24_hour_format (CalendarModel *model,
                       gboolean       use_24_hour_format)
{
    g_return_if_fail (IS_CALENDAR_MODEL (model));

    if (model->priv->use_24_hour_format != use_24_hour_format) {
        model->priv->use_24_hour_format = use_24_hour_format;
        /* Get the views to redraw themselves. */
        e_table_model_changed (E_TABLE_MODEL (model));
    }
}


void
calendar_model_set_default_category (CalendarModel  *model,
                     gchar      *default_category)
{
    g_return_if_fail (IS_CALENDAR_MODEL (model));

    g_free (model->priv->default_category);
    model->priv->default_category = g_strdup (default_category);
}


static void
calendar_model_collect_all_categories   (CalendarModel  *model)
{
    CalendarModelPrivate *priv;
    CalComponent *comp;
    int i;

    priv = model->priv;

    /* Destroy the current tree and start from scratch. */
    g_tree_traverse (priv->categories, (GTraverseFunc) g_free,
             G_PRE_ORDER, NULL);
    g_tree_destroy (priv->categories);

    priv->categories = g_tree_new ((GCompareFunc)strcmp);

    for (i = 0; i < priv->objects->len; i++) {
        comp = g_array_index (priv->objects, CalComponent *, i);
        calendar_model_collect_categories (model, comp);
    }

    gtk_signal_emit (GTK_OBJECT (model),
             calendar_model_signals [CATEGORIES_CHANGED]);
}


static gboolean
calendar_model_collect_categories   (CalendarModel  *model,
                     CalComponent   *comp)
{
    CalendarModelPrivate *priv;
    GSList *categories_list, *elem;
    gboolean changed = FALSE;

    priv = model->priv;

    cal_component_get_categories_list (comp, &categories_list);

    for (elem = categories_list; elem; elem = elem->next) {
        if (!g_tree_lookup (priv->categories, elem->data)) {
            /* We store a '1' as the data, just so we can use
               g_tree_lookup() on it. Note that we don't free
               the string since it is now part of the tree. */
            g_tree_insert (priv->categories, elem->data,
                       GINT_TO_POINTER (1));
            changed = TRUE;
        } else {
            g_free (elem->data);
        }
    }

    g_slist_free (categories_list);

    return changed;
}


GTree*
calendar_model_get_categories       (CalendarModel  *model)
{
    g_return_val_if_fail (IS_CALENDAR_MODEL (model), NULL);

    return model->priv->categories;
}


/* The current timezone. */
icaltimezone*
calendar_model_get_timezone     (CalendarModel  *model)
{
    g_return_val_if_fail (IS_CALENDAR_MODEL (model), NULL);

    return model->priv->zone;
}


void
calendar_model_set_timezone     (CalendarModel  *model,
                     icaltimezone   *zone)
{
    g_return_if_fail (IS_CALENDAR_MODEL (model));

    if (model->priv->zone != zone) {
        model->priv->zone = zone;

        /* The timezone affects the times shown for COMPLETED and
           maybe other fields, so we need to redisplay everything. */
        e_table_model_changed (E_TABLE_MODEL (model));
    }
}