Use schedule timezone for RotationConfigForm

Use the schedule timezone to configure rotations. All times entered
are handled in the schedule timezone.

Author: jrauh01

application/forms/RotationConfigForm.php

@@ -6,13 +6,15 @@
 
 use DateInterval;
 use DateTime;
+use DateTimeZone;
 use Generator;
 use Icinga\Exception\ConfigurationError;
 use Icinga\Exception\Http\HttpNotFoundException;
 use Icinga\Module\Notifications\Common\Database;
 use Icinga\Module\Notifications\Model\Contact;
 use Icinga\Module\Notifications\Model\Contactgroup;
 use Icinga\Module\Notifications\Model\Rotation;
+use Icinga\Module\Notifications\Model\Schedule;
 use Icinga\Module\Notifications\Model\TimeperiodEntry;
 use Icinga\Util\Json;
 use Icinga\Web\Session;
@@ -1145,7 +1147,8 @@ function ($value, $validator) use ($earliestHandoff, $firstHandoff, $latestHando
                             (new \IntlDateFormatter(
                                 \Locale::getDefault(),
                                 \IntlDateFormatter::MEDIUM,
-                                \IntlDateFormatter::SHORT
+                                \IntlDateFormatter::SHORT,
+                                $this->getScheduleTimezone()
                             ))->format($actualFirstHandoff)
                         );
                     }
@@ -1270,7 +1273,8 @@ private function parseDateAndTime(?string $date = null, ?string $time = null): D
             return (new DateTime())->setTime(0, 0);
         }
 
-        $datetime = DateTime::createFromFormat($format, $expression);
+        $datetime = DateTime::createFromFormat($format, $expression, new DateTimeZone($this->getScheduleTimezone()));
+
         if ($datetime === false) {
             $datetime = (new DateTime())->setTime(0, 0);
         } elseif ($time === null) {
@@ -1665,4 +1669,17 @@ public function hasChanges(): bool
 
         return ! empty(array_udiff_assoc($values, $dbValuesToCompare, $checker));
     }
+
+    /**
+     * Get the timezone of the schedule
+     *
+     * @return string The timezone identifier
+     */
+    protected function getScheduleTimezone(): string
+    {
+        return Schedule::on(Database::get())
+            ->filter(Filter::equal('id', $this->scheduleId))
+            ->first()
+            ->timezone;
+    }
 }