ThemePicker::setDefaultTheme

public function setDefaultTheme($themeId, $currentUserId = 0): bool
{
	if (
		!$this->isValidTheme($themeId)
		|| $this->getEntityType() !== self::ENTITY_TYPE_USER
	)
	{
		return false;
	}

	$currentUserId = (int)$currentUserId;
	if ($currentUserId <= 0)
	{
		$currentUserId = (is_object($GLOBALS["USER"]) ? (int)$GLOBALS["USER"]->getID() : 0);
	}

	if ($currentUserThemeFields = ThemeTable::getList([
		'filter' => [
			'=USER_ID' => $currentUserId,
			'=ENTITY_TYPE' => $this->getEntityType(),
			'=ENTITY_ID' => $currentUserId,
			'=CONTEXT' => $this->getContext(),
		],
		'select' => [ 'ID' ]
	])->fetch())
	{
		ThemeTable::delete($currentUserThemeFields['ID']);
	}

	return ThemeTable::set([
		'THEME_ID' => $themeId,
		'USER_ID' => $currentUserId,
		'ENTITY_TYPE' => $this->getEntityType(),
		'ENTITY_ID' => 0,
		'CONTEXT' => $this->getContext(),
	]);
}