[gnome-calendar/cherry-pick-89e90fec] Merge branch 'wip/mcatanzaro/timezone' into 'master'

[Michael Catanzaro <mcatanzaro src gnome org>]

commit e1010b7caa18689ba8204afb2583853c6011769c
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Wed Dec 6 10:45:42 2017 +0000

    Merge branch 'wip/mcatanzaro/timezone' into 'master'
    
    Events created in month or year view are created with incorrect time and missing timezone
    
    Closes #168
    
    See merge request GNOME/gnome-calendar!7
    
    (cherry picked from commit 89e90fec6d01d538ede9a2764c29dae41daf506d)
    
    ce8e8c21 edit-dialog: Fix timezone for events created in month view
    1d8a1646 event: Fix changing the timezone
    281ed44f Revert "event: correctly store timezones"
    a7304ed9 event: Restore handling of all day events
    0724d409 event: Save local time correctly

 src/gcal-edit-dialog.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)
---
diff --git a/src/gcal-edit-dialog.c b/src/gcal-edit-dialog.c
index 359b94a0..fbba3a1c 100644
--- a/src/gcal-edit-dialog.c
+++ b/src/gcal-edit-dialog.c
@@ -452,6 +452,7 @@ action_button_clicked (GtkWidget *widget,
       GcalRecurrenceFrequency freq;
       GcalRecurrence *old_recur;
       GDateTime *start_date, *end_date;
+      gboolean was_all_day;
       gboolean all_day;
       gchar *note_text;
 
@@ -468,6 +469,7 @@ action_button_clicked (GtkWidget *widget,
 
       /* Update all day */
       all_day = gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (dialog->all_day_check));
+      was_all_day = gcal_event_get_all_day (dialog->event);
 
       gcal_event_set_all_day (dialog->event, all_day);
 
@@ -483,7 +485,7 @@ action_button_clicked (GtkWidget *widget,
 
       /*
        * Update start & end dates. The dates are already translated to the current
-       * timezone.
+       * timezone (unless the event used to be all day, but no longer is).
        */
       start_date = gcal_edit_dialog_get_date_start (dialog);
       end_date = gcal_edit_dialog_get_date_end (dialog);
@@ -500,6 +502,23 @@ action_button_clicked (GtkWidget *widget,
           g_clear_pointer (&end_date, g_date_time_unref);
           end_date = fake_end_date;
         }
+      else if (!all_day && was_all_day)
+        {
+          /* When an all day event is changed to be not an all day event, we
+           * need to correct for the fact that the event's timezone was until
+           * now set to UTC. That means we need to change the timezone to
+           * localtime now, or else it will be saved incorrectly.
+           */
+          GDateTime *localtime_date;
+
+          localtime_date = g_date_time_to_local (start_date);
+          g_clear_pointer (&start_date, g_date_time_unref);
+          start_date = localtime_date;
+
+          localtime_date = g_date_time_to_local (end_date);
+          g_clear_pointer (&end_date, g_date_time_unref);
+          end_date = localtime_date;
+        }
 
       gcal_event_set_date_start (dialog->event, start_date);
       gcal_event_set_date_end (dialog->event, end_date);