MigrateFromCaldav::doMigration

static function doMigration()
{
	global $DB;
	$strSql = "SHOW TABLES LIKE 'b_calendar_tmp_migration'";
	$sqlResult = $DB->Query($strSql);
	$canDoMigration = false;
	if ($tableExists = $sqlResult->Fetch())
	{
		$canDoMigration = true;
	}

	//Stop migration process if impossible or empty table or table not exists.
	if (!BitrixMainLoader::includeModule('dav') || !$canDoMigration)
	{
		CCalendar::ClearCache();
		CAgent::RemoveAgent("Bitrix\Calendar\Update\MigrateFromCaldav::doMigration();", "calendar");
		return null;
	}
	else
	{
		//Do migration process
		$query = $DB->Query("SELECT * FROM b_calendar_tmp_migration WHERE ATTEMPTS < 10 ORDER BY ATTEMPTS ASC LIMIT 3");
		$hasRows = false;
		while ($row = $query->Fetch())
		{
			$hasRows = true;
			$connectionId = $row['CONNECTION_ID'];
			$userId = intval($row['USER_ID']);
			$sectionsList = checkSerializedData($row['SECTION_DATA']) ? unserialize($row['SECTION_DATA'], ['allowed_classes' => false]) : false;

			if ($sectionsList)
			{
				$googleApiConnection = new GoogleApiSync($userId);
				$googleCalendars = $googleApiConnection->getCalendarItems();
				$errorCode = $googleApiConnection->getTransportConnectionError();


				if (!$errorCode)
				{
					foreach ($sectionsList as $section)
					{
						$localEventsList = CCalendarEvent::getList(array(
							'userId' => $userId,
							'arFilter' => array('SECTION' => $section['ID'])
						));

						$davXmlId = preg_replace('/(/caldav/v2/)|(/events/)/', '', $section['CAL_DAV_CAL'], -1, $replaced);
						if ($replaced == 2)
						{
							$isVirtual = preg_match('/(@virtual)/', $davXmlId);

							foreach ($googleCalendars as $googleCalendar)
							{
								if ($isVirtual && ($googleCalendar['id'] == $section['DESCRIPTION'] || $googleCalendar['summary'] == $section['NAME']))
								{
									$DB->Query("UPDATE b_calendar_section SET GAPI_CALENDAR_ID = '" . $DB->ForSql($googleCalendar['id']) . "', TEXT_COLOR = '" . $DB->ForSql($googleCalendar['textColor']) . "', COLOR = '" . $DB->ForSql($googleCalendar['backgroundColor']) . "' WHERE ID = '" . intval($section['ID']) . "'");
									continue;
								}
								if ($davXmlId != $googleCalendar['id'])
								{
									continue;
								}
								$section['GAPI_CALENDAR_ID'] = $davXmlId;
								$sectionSyncToken = NULL;
								$externalEvents = $googleApiConnection->getEvents($section);
								$sectionSyncToken = $googleApiConnection->getNextSyncToken();

								if ($localEventsList)
								{
									foreach ($localEventsList as $localEvent)
									{
										if (preg_match('/(@google.com)/', $localEvent['DAV_XML_ID']) === 1)
											continue;
										foreach ($externalEvents as $externalEvent)
										{
											if (!empty($localEvent['DAV_XML_ID']) && !empty($externalEvent['iCalUID']) && ($localEvent['DAV_XML_ID'] == $externalEvent['iCalUID']))
											{
												$localEvent['DAV_XML_ID'] = $externalEvent['DAV_XML_ID'];

												$newEventData = array_merge(
													$localEvent,
													array(
														'SECTIONS' => array($section['ID']),
														'OWNER_ID' => $userId,
														'userId' => $userId,
													)
												);
												CCalendarEvent::Edit(array('arFields' => $newEventData));
												break;
											}
										}
									}
								}
								$DB->Query("UPDATE b_calendar_section SET GAPI_CALENDAR_ID = '" . $DB->ForSql($davXmlId) . "', SYNC_TOKEN = '" . $DB->ForSql($sectionSyncToken) . "', TEXT_COLOR = '" . $DB->ForSql($googleCalendar['textColor']) . "', COLOR = '" . $DB->ForSql($googleCalendar['backgroundColor']) . "' WHERE ID = '" . intval($section['ID']) . "'");
								break;
							}
						}
					}
					//In a case when google api can return data and we have access to it
					$DB->Query("DELETE FROM b_calendar_tmp_migration WHERE ID = '" . intval($row['ID']) . "'");

					CDavConnection::Update($connectionId, ['ACCOUNT_TYPE' => GoogleHelper::GOOGLE_ACCOUNT_TYPE_API, 'SERVER' => GoogleHelper::GOOGLE_SERVER_PATH_V3], false);
				}
				else
				{
					if ($row['ATTEMPTS'] >= 1000)
					{
						$DB->Query("DELETE FROM b_calendar_tmp_migration WHERE ID = " . intval($row['ID']));
						CDavConnection::SetLastResult($connectionId, "GAPI_MIGRATE_ERROR");
					}
					$DB->Query("UPDATE b_calendar_tmp_migration SET ATTEMPTS = ATTEMPTS + 1 WHERE ID = " . intval($row['ID']));
				}
			}
			else
			{
				//In a case when no tables for migration received.
				$DB->Query("DELETE FROM b_calendar_tmp_migration WHERE ID = '" . intval($row['ID']) . "'");
				CDavConnection::Update($connectionId, array('ACCOUNT_TYPE' => GoogleHelper::GOOGLE_ACCOUNT_TYPE_API, 'SERVER' => GoogleHelper::GOOGLE_SERVER_PATH_V3), false);
			}
		}

		if (!$hasRows)
		{
			$DB->Query("DROP TABLE b_calendar_tmp_migration");
		}

		return "Bitrix\Calendar\Update\MigrateFromCaldav::doMigration();";
	}
}