first bootstrap for handling calendar range sync frommsgraph

src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/MSGraph/RemoteEventConverter.php

@@ -19,6 +19,7 @@ use Chill\PersonBundle\Entity\Person;
 use Chill\PersonBundle\Templating\Entity\PersonRenderInterface;
 use DateTimeImmutable;
 use DateTimeZone;
+use RuntimeException;
 use Symfony\Component\Templating\EngineInterface;
 use Symfony\Contracts\Translation\TranslatorInterface;
 
@@ -28,10 +29,16 @@ use Symfony\Contracts\Translation\TranslatorInterface;
  */
 class RemoteEventConverter
 {
+    /**
+     * valid when the remote string contains also a timezone, like in
+     * lastModifiedDate
+     */
     public const REMOTE_DATETIMEZONE_FORMAT = 'Y-m-d\\TH:i:s.u?P';
 
     private const REMOTE_DATE_FORMAT = 'Y-m-d\TH:i:s.u0';
 
+    private const REMOTE_DATETIME_WITHOUT_TZ_FORMAT = 'Y-m-d\TH:i:s.u?';
+
     private DateTimeZone $defaultDateTimeZone;
 
     private EngineInterface $engine;
@@ -147,6 +154,34 @@ class RemoteEventConverter
         );
     }
 
+    public static function convertStringDateWithoutTimezone(string $date): DateTimeImmutable
+    {
+        $d = DateTimeImmutable::createFromFormat(
+            self::REMOTE_DATETIME_WITHOUT_TZ_FORMAT,
+            $date,
+            self::getRemoteTimeZone()
+        );
+
+        if (false === $d) {
+            throw new RuntimeException("could not convert string date to datetime: {$date}");
+        }
+
+        return $d->setTimezone((new DateTimeImmutable())->getTimezone());
+    }
+
+    public static function convertStringDateWithTimezone(string $date): DateTimeImmutable
+    {
+        $d = DateTimeImmutable::createFromFormat(self::REMOTE_DATETIMEZONE_FORMAT, $date);
+
+        if (false === $d) {
+            throw new RuntimeException("could not convert string date to datetime: {$date}");
+        }
+
+        $d->setTimezone((new DateTimeImmutable())->getTimezone());
+
+        return $d;
+    }
+
     public function convertToRemote(array $event): RemoteEvent
     {
         $startDate =