bp_xprofile_get_fields_by_visibility_levels( int $user_id, array $levels = array() )

function bp_xprofile_get_fields_by_visibility_levels( $user_id, $levels = array() ) {
	if ( !is_array( $levels ) ) {
		$levels = (array)$levels;
	}

	$user_visibility_levels = bp_get_user_meta( $user_id, 'bp_xprofile_visibility_levels', true );

	// Parse the user-provided visibility levels with the default levels, which may take
	// precedence.
	$default_visibility_levels = BP_XProfile_Group::fetch_default_visibility_levels();

	foreach( (array) $default_visibility_levels as $d_field_id => $defaults ) {
		// If the admin has forbidden custom visibility levels for this field, replace
		// the user-provided setting with the default specified by the admin.
		if ( isset( $defaults['allow_custom'] ) && isset( $defaults['default'] ) && 'disabled' == $defaults['allow_custom'] ) {
			$user_visibility_levels[$d_field_id] = $defaults['default'];
		}
	}

	$field_ids = array();
	foreach( (array) $user_visibility_levels as $field_id => $field_visibility ) {
		if ( in_array( $field_visibility, $levels ) ) {
			$field_ids[] = $field_id;
		}
	}

	// Never allow the fullname field to be excluded.
	if ( in_array( 1, $field_ids ) ) {
		$key = array_search( 1, $field_ids );
		unset( $field_ids[$key] );
	}

	return $field_ids;
}