feat: parse one calendar event with libical (item 206)

1 files changed, 171 insertions, 0 deletions

diff --git a/src/calendarstore.cpp b/src/calendarstore.cpp
new file mode 100644
index 0000000..6cc2bcd
--- /dev/null
+++ b/src/calendarstore.cpp
@@ -0,0 +1,171 @@
+/*
+ * qtmaildir - a Qt6 mail client for notmuch-indexed Maildirs
+ * Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "calendarstore.h"
+#include "icalraii.h"
+
+#include <QTimeZone>
+
+namespace {
+
+QString str(const char *s) { return s ? QString::fromUtf8(s) : QString(); }
+
+QByteArray tzidOf(icalproperty *prop)
+{
+    if (!prop)
+        return {};
+    icalparameter *param = icalproperty_get_first_parameter(prop, ICAL_TZID_PARAMETER);
+    return param ? QByteArray(icalparameter_get_tzid(param)) : QByteArray();
+}
+
+/// One icaltimetype to a QDateTime, in this order (spec, "Time and
+/// recurrence"): a date is local midnight; UTC is UTC; a zone libical resolved
+/// (an embedded VTIMEZONE) converts through libical; a TZID libical could not
+/// resolve is tried as an IANA name through QTimeZone; anything else is local
+/// wall-clock time, and an unresolvable TZID sets *unknownZone.
+QDateTime toDateTime(icaltimetype t, const QByteArray &tzid, bool *unknownZone)
+{
+    if (icaltime_is_null_time(t))
+        return {};
+    const QDate date(t.year, t.month, t.day);
+    if (t.is_date)
+        return QDateTime(date, QTime(0, 0));
+    const QTime time(t.hour, t.minute, t.second);
+    if (icaltime_is_utc(t))
+        return QDateTime(date, time, QTimeZone::utc());
+    if (t.zone) {
+        const icaltimetype utc =
+            icaltime_convert_to_zone(t, icaltimezone_get_utc_timezone());
+        return QDateTime(QDate(utc.year, utc.month, utc.day),
+                         QTime(utc.hour, utc.minute, utc.second), QTimeZone::utc());
+    }
+    if (!tzid.isEmpty()) {
+        const QTimeZone zone(tzid);
+        if (zone.isValid())
+            return QDateTime(date, time, zone);
+        if (unknownZone)
+            *unknownZone = true;
+    }
+    return QDateTime(date, time);
+}
+
+CalPerson personOf(icalproperty *prop)
+{
+    CalPerson person;
+    QString value = str(icalproperty_get_value_as_string(prop));
+    if (value.startsWith(QLatin1String("mailto:"), Qt::CaseInsensitive))
+        value = value.mid(7);
+    person.address = value;
+    person.name = str(icalproperty_get_parameter_as_string(prop, "CN"));
+    person.partstat = str(icalproperty_get_parameter_as_string(prop, "PARTSTAT"));
+    return person;
+}
+
+/// The VEVENT without a RECURRENCE-ID, or the first VEVENT if every one has.
+icalcomponent *masterOf(icalcomponent *root)
+{
+    icalcomponent *first = nullptr;
+    for (icalcomponent *c = icalcomponent_get_first_component(root, ICAL_VEVENT_COMPONENT);
+         c; c = icalcomponent_get_next_component(root, ICAL_VEVENT_COMPONENT)) {
+        if (!first)
+            first = c;
+        if (!icalcomponent_get_first_property(c, ICAL_RECURRENCEID_PROPERTY))
+            return c;
+    }
+    return first;
+}
+
+IcalComponent parseRoot(const QByteArray &text)
+{
+    IcalComponent root(icalparser_parse_string(text.constData()));
+    if (root && icalcomponent_isa(root.get()) == ICAL_VEVENT_COMPONENT) {
+        // A bare VEVENT with no VCALENDAR around it: wrap it, so every
+        // caller walks the same shape.
+        IcalComponent cal(icalcomponent_new(ICAL_VCALENDAR_COMPONENT));
+        icalcomponent_add_component(cal.get(), root.release());
+        return cal;
+    }
+    return root;
+}
+
+/// The end of a component: DTEND, else DTSTART + DURATION (libical computes
+/// both through get_dtend), else one day for a date and the start otherwise.
+QDateTime endOf(icalcomponent *c, const QDateTime &start, bool allDay, bool *unknownZone)
+{
+    icalproperty *endProp = icalcomponent_get_first_property(c, ICAL_DTEND_PROPERTY);
+    const icaltimetype end = icalcomponent_get_dtend(c);
+    if (!icaltime_is_null_time(end))
+        return toDateTime(end, tzidOf(endProp ? endProp
+                                  : icalcomponent_get_first_property(c, ICAL_DTSTART_PROPERTY)),
+                          unknownZone);
+    return allDay ? start.addDays(1) : start;
+}
+
+} // namespace
+
+namespace CalendarStore {
+
+CalEvent parseEvent(const QByteArray &text, const QString &filePath,
+                    const QString &collectionDir, bool *unknownZone)
+{
+    CalEvent event;
+    event.filePath = filePath;
+    event.collectionDir = collectionDir;
+    event.rawText = text;
+    if (unknownZone)
+        *unknownZone = false;
+
+    IcalComponent root = parseRoot(text);
+    if (!root)
+        return event;
+    icalcomponent *master = masterOf(root.get());
+    if (!master)
+        return event;
+
+    event.uid = str(icalcomponent_get_uid(master));
+    event.summary = str(icalcomponent_get_summary(master));
+    event.location = str(icalcomponent_get_location(master));
+    event.description = str(icalcomponent_get_description(master));
+    event.sequence = icalcomponent_get_sequence(master);
+
+    icalproperty *startProp = icalcomponent_get_first_property(master, ICAL_DTSTART_PROPERTY);
+    const icaltimetype start = icalcomponent_get_dtstart(master);
+    event.allDay = start.is_date;
+    event.start = toDateTime(start, tzidOf(startProp), unknownZone);
+    event.end = endOf(master, event.start, event.allDay, unknownZone);
+
+    event.hasAlarm = icalcomponent_get_first_component(master, ICAL_VALARM_COMPONENT);
+    if (icalproperty *org = icalcomponent_get_first_property(master, ICAL_ORGANIZER_PROPERTY))
+        event.organizer = personOf(org);
+    for (icalproperty *a = icalcomponent_get_first_property(master, ICAL_ATTENDEE_PROPERTY);
+         a; a = icalcomponent_get_next_property(master, ICAL_ATTENDEE_PROPERTY))
+        event.attendees.append(personOf(a));
+
+    // Recurrence, exceptions and overrides: Task 4.
+    return event;
+}
+
+LoadResult load(const QString &) { return {}; }
+QList<Occurrence> occurrences(const QList<CalEvent> &, const QDateTime &, const QDateTime &) { return {}; }
+bool isEditable(const CalEvent &, const CalCollection &, const QStringList &) { return false; }
+QByteArray applyEdit(const QByteArray &, const EventEdit &, Scope, const QDateTime &) { return {}; }
+QByteArray newEvent(const EventEdit &, const QByteArray &) { return {}; }
+QByteArray deleteOccurrence(const QByteArray &, const QDateTime &) { return {}; }
+bool sameMeaning(const QByteArray &, const QByteArray &) { return false; }
+
+}  // namespace CalendarStore