BP_Activity_Activity::get_scope_query_sql( mixed $scope = false, array $r = array() )

	public static function get_scope_query_sql( $scope = false, $r = array() ) {

		// Define arrays for future use.
		$query_args = array();
		$override   = array();
		$retval     = array();

		// Check for array of scopes.
		if ( is_array( $scope ) ) {
			$scopes = $scope;

			// Explode a comma separated string of scopes.
		} elseif ( is_string( $scope ) ) {
			$scopes = explode( ',', $scope );
		}

		// Bail if no scope passed.
		if ( empty( $scopes ) ) {
			return false;
		}

		// Helper to easily grab the 'user_id'.
		if ( ! empty( $r['filter']['user_id'] ) ) {
			$r['user_id'] = $r['filter']['user_id'];
		}

		// Parse each scope; yes! we handle multiples!
		foreach ( $scopes as $scope ) {
			$scope_args = array();

			/**
			 * Plugins can hook here to set their activity arguments for custom scopes.
			 *
			 * This is a dynamic filter based on the activity scope. eg:
			 *   - 'bp_activity_set_groups_scope_args'
			 *   - 'bp_activity_set_friends_scope_args'
			 *
			 * To see how this filter is used, plugin devs should check out:
			 *   - bp_groups_filter_activity_scope() - used for 'groups' scope
			 *   - bp_friends_filter_activity_scope() - used for 'friends' scope
			 *
			 * @since BuddyPress 2.2.0
			 *
			 * @param array {
			 *     Activity query clauses.
			 *     @type array {
			 *         Activity arguments for your custom scope.
			 *         See {@link BP_Activity_Query::_construct()} for more details.
			 *     }
			 *     @type array  $override Optional. Override existing activity arguments passed by $r.
			 *     }
			 * }
			 * @param array $r Current activity arguments passed in BP_Activity_Activity::get().
			 */
			$scope_args = apply_filters( "bp_activity_set_{$scope}_scope_args", array(), $r );

			if ( ! empty( $scope_args ) ) {
				// Merge override properties from other scopes
				// this might be a problem...
				if ( ! empty( $scope_args['override'] ) ) {
					$override = array_merge( $override, $scope_args['override'] );
					unset( $scope_args['override'] );
				}

				// Save scope args.
				if ( ! empty( $scope_args ) ) {
					$query_args[] = $scope_args;
				}
			}
		}

		if ( ! empty( $query_args ) ) {
			// Set relation to OR.
			$query_args['relation'] = 'OR';

			$query = new BP_Activity_Query( $query_args );
			$sql   = $query->get_sql();
			if ( ! empty( $sql ) ) {
				$retval['sql'] = $sql;
			}
		}

		if ( ! empty( $override ) ) {
			$retval['override'] = $override;
		}

		return $retval;
	}