groups_format_notifications( string $action, int $item_id, int $secondary_item_id, int $total_items, string $format = 'string' )

function groups_format_notifications( $action, $item_id, $secondary_item_id, $total_items, $format = 'string' ) {

	switch ( $action ) {
		case 'new_membership_request':
			$group_id = $item_id;
			$requesting_user_id = $secondary_item_id;

			$group = groups_get_group( $group_id );
			$group_link = bp_get_group_permalink( $group );
			$amount = 'single';

			// Set up the string and the filter
			// because different values are passed to the filters,
			// we'll return values inline.
			if ( (int) $total_items > 1 ) {
				$text = sprintf( __( '%1$d new membership requests for the group "%2$s"', 'buddyboss' ), (int) $total_items, $group->name );
				$amount = 'multiple';
				$notification_link = $group_link . 'admin/membership-requests/?n=1';

				if ( 'string' == $format ) {

					/**
					 * Filters groups multiple new membership request notification for string format.
					 *
					 * This is a dynamic filter that is dependent on item count and action.
					 * Complete filter - bp_groups_multiple_new_membership_requests_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param string $string            HTML anchor tag for request.
					 * @param string $group_link        The permalink for the group.
					 * @param int    $total_items       Total number of membership requests.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . 's_notification', '<a href="' . $notification_link . '">' . $text . '</a>', $group_link, $total_items, $group->name, $text, $notification_link );
				} else {

					/**
					 * Filters groups multiple new membership request notification for any non-string format.
					 *
					 * This is a dynamic filter that is dependent on item count and action.
					 * Complete filter - bp_groups_multiple_new_membership_requests_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param array  $array             Array holding permalink and content for notification.
					 * @param string $group_link        The permalink for the group.
					 * @param int    $total_items       Total number of membership requests.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . 's_notification', array(
						'link' => $notification_link,
						'text' => $text
					), $group_link, $total_items, $group->name, $text, $notification_link );
				}
			} else {
				$user_fullname = bp_core_get_user_displayname( $requesting_user_id );
				$text = sprintf( __( '%s requests group membership', 'buddyboss' ), $user_fullname );
				$notification_link = $group_link . 'admin/membership-requests/?n=1';

				if ( 'string' == $format ) {

					/**
					 * Filters groups single new membership request notification for string format.
					 *
					 * This is a dynamic filter that is dependent on item count and action.
					 * Complete filter - bp_groups_single_new_membership_request_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param string $string            HTML anchor tag for request.
					 * @param string $group_link        The permalink for the group.
					 * @param string $user_fullname     Full name of requesting user.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', '<a href="' . $notification_link . '">' . $text . '</a>', $group_link, $user_fullname, $group->name, $text, $notification_link );
				} else {

					/**
					 * Filters groups single new membership request notification for any non-string format.
					 *
					 * This is a dynamic filter that is dependent on item count and action.
					 * Complete filter - bp_groups_single_new_membership_request_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param array  $array             Array holding permalink and content for notification.
					 * @param string $group_link        The permalink for the group.
					 * @param string $user_fullname     Full name of requesting user.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', array(
						'link' => $notification_link,
						'text' => $text
					), $group_link, $user_fullname, $group->name, $text, $notification_link );
				}
			}

			break;

		case 'membership_request_accepted':
			$group_id = $item_id;

			$group = groups_get_group( $group_id );
			$group_link = bp_get_group_permalink( $group );
			$amount = 'single';

			if ( (int) $total_items > 1 ) {
				$text = sprintf( __( '%d accepted group membership requests', 'buddyboss' ), (int) $total_items, $group->name );
				$amount = 'multiple';
				$notification_link = trailingslashit( bp_loggedin_user_domain() . bp_get_groups_slug() ) . '?n=1';

				if ( 'string' == $format ) {

					/**
					 * Filters multiple accepted group membership requests notification for string format.
					 * Complete filter - bp_groups_multiple_membership_request_accepted_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param string $string            HTML anchor tag for notification.
					 * @param int    $total_items       Total number of accepted requests.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', '<a href="' . $notification_link . '">' . $text . '</a>', $total_items, $group->name, $text, $notification_link );
				} else {

					/**
					 * Filters multiple accepted group membership requests notification for non-string format.
					 * Complete filter - bp_groups_multiple_membership_request_accepted_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param array  $array             Array holding permalink and content for notification
					 * @param int    $total_items       Total number of accepted requests.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', array(
						'link' => $notification_link,
						'text' => $text
					), $total_items, $group->name, $text, $notification_link );
				}
			} else {
				$text = sprintf( __( 'Membership for group "%s" accepted', 'buddyboss' ), $group->name );
				$filter = 'bp_groups_single_membership_request_accepted_notification';
				$notification_link = $group_link . '?n=1';

				if ( 'string' == $format ) {

					/**
					 * Filters single accepted group membership request notification for string format.
					 * Complete filter - bp_groups_single_membership_request_accepted_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param string $string            HTML anchor tag for notification.
					 * @param string $group_link        The permalink for the group.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', '<a href="' . $notification_link . '">' . $text . '</a>', $group_link, $group->name, $text, $notification_link );
				} else {

					/**
					 * Filters single accepted group membership request notification for non-string format.
					 * Complete filter - bp_groups_single_membership_request_accepted_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param array  $array             Array holding permalink and content for notification.
					 * @param string $group_link        The permalink for the group.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( $filter, array(
						'link' => $notification_link,
						'text' => $text
					), $group_link, $group->name, $text, $notification_link );
				}
			}

			break;

		case 'membership_request_rejected':
			$group_id = $item_id;

			$group = groups_get_group( $group_id );
			$group_link = bp_get_group_permalink( $group );
			$amount = 'single';

			if ( (int) $total_items > 1 ) {
				$text = sprintf( __( '%d rejected group membership requests', 'buddyboss' ), (int) $total_items, $group->name );
				$amount = 'multiple';
				$notification_link = trailingslashit( bp_loggedin_user_domain() . bp_get_groups_slug() ) . '?n=1';

				if ( 'string' == $format ) {

					/**
					 * Filters multiple rejected group membership requests notification for string format.
					 * Complete filter - bp_groups_multiple_membership_request_rejected_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param string $string            HTML anchor tag for notification.
					 * @param int    $total_items       Total number of rejected requests.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', '<a href="' . $notification_link . '">' . $text . '</a>', $total_items, $group->name );
				} else {

					/**
					 * Filters multiple rejected group membership requests notification for non-string format.
					 * Complete filter - bp_groups_multiple_membership_request_rejected_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param array  $array             Array holding permalink and content for notification.
					 * @param int    $total_items       Total number of rejected requests.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', array(
						'link' => $notification_link,
						'text' => $text
					), $total_items, $group->name, $text, $notification_link );
				}
			} else {
				$text = sprintf( __( 'Membership for group "%s" rejected', 'buddyboss' ), $group->name );
				$notification_link = $group_link . '?n=1';

				if ( 'string' == $format ) {

					/**
					 * Filters single rejected group membership requests notification for string format.
					 * Complete filter - bp_groups_single_membership_request_rejected_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param string $string            HTML anchor tag for notification.
					 * @param int    $group_link        The permalink for the group.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', '<a href="' . $notification_link . '">' . $text . '</a>', $group_link, $group->name, $text, $notification_link );
				} else {

					/**
					 * Filters single rejected group membership requests notification for non-string format.
					 * Complete filter - bp_groups_single_membership_request_rejected_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param array  $array             Array holding permalink and content for notification.
					 * @param int    $group_link        The permalink for the group.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', array(
						'link' => $notification_link,
						'text' => $text
					), $group_link, $group->name, $text, $notification_link );
				}
			}

			break;

		case 'member_promoted_to_admin':
			$group_id = $item_id;

			$group = groups_get_group( $group_id );
			$group_link = bp_get_group_permalink( $group );
			$amount = 'single';

			if ( (int) $total_items > 1 ) {
				$text = sprintf( __( 'You were promoted to the role of %s in %d groups', 'buddyboss' ), strtolower( get_group_role_label( $group_id, 'organizer_singular_label_name' ) ), (int) $total_items );
				$amount = 'multiple';
				$notification_link = trailingslashit( bp_loggedin_user_domain() . bp_get_groups_slug() ) . '?n=1';

				if ( 'string' == $format ) {
					/**
					 * Filters multiple promoted to group admin notification for string format.
					 * Complete filter - bp_groups_multiple_member_promoted_to_admin_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param string $string            HTML anchor tag for notification.
					 * @param int    $total_items       Total number of rejected requests.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', '<a href="' . $notification_link . '">' . $text . '</a>', $total_items, $text, $notification_link );
				} else {
					/**
					 * Filters multiple promoted to group admin notification for non-string format.
					 * Complete filter - bp_groups_multiple_member_promoted_to_admin_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param array  $array             Array holding permalink and content for notification.
					 * @param int    $total_items       Total number of rejected requests.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', array(
						'link' => $notification_link,
						'text' => $text
					), $total_items, $text, $notification_link );
				}
			} else {
				$text = sprintf( __( 'You were promoted to the role of %s in the group "%s"', 'buddyboss' ), strtolower( get_group_role_label( $group_id, 'organizer_singular_label_name' ) ), $group->name );
				$notification_link = $group_link . '?n=1';

				if ( 'string' == $format ) {
					/**
					 * Filters single promoted to group admin notification for non-string format.
					 * Complete filter - bp_groups_single_member_promoted_to_admin_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param string $string            HTML anchor tag for notification.
					 * @param int    $group_link        The permalink for the group.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', '<a href="' . $notification_link . '">' . $text . '</a>', $group_link, $group->name, $text, $notification_link );
				} else {
					/**
					 * Filters single promoted to group admin notification for non-string format.
					 * Complete filter - bp_groups_single_member_promoted_to_admin_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param array  $array             Array holding permalink and content for notification.
					 * @param int    $group_link        The permalink for the group.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', array(
						'link' => $notification_link,
						'text' => $text
					), $group_link, $group->name, $text, $notification_link );
				}
			}

			break;

		case 'member_promoted_to_mod':
			$group_id = $item_id;

			$group = groups_get_group( $group_id );
			$group_link = bp_get_group_permalink( $group );
			$amount = 'single';

			if ( (int) $total_items > 1 ) {
				$text = sprintf( __( 'You were promoted to a %s in %d groups', 'buddyboss' ), strtolower( get_group_role_label( $group_id, 'moderator_singular_label_name' ) ), (int) $total_items );
				$amount = 'multiple';
				$notification_link = trailingslashit( bp_loggedin_user_domain() . bp_get_groups_slug() ) . '?n=1';

				if ( 'string' == $format ) {
					/**
					 * Filters multiple promoted to group mod notification for string format.
					 * Complete filter - bp_groups_multiple_member_promoted_to_mod_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param string $string            HTML anchor tag for notification.
					 * @param int    $total_items       Total number of rejected requests.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', '<a href="' . $notification_link . '">' . $text . '</a>', $total_items, $text, $notification_link );
				} else {
					/**
					 * Filters multiple promoted to group mod notification for non-string format.
					 * Complete filter - bp_groups_multiple_member_promoted_to_mod_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param array  $array             Array holding permalink and content for notification.
					 * @param int    $total_items       Total number of rejected requests.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', array(
						'link' => $notification_link,
						'text' => $text
					), $total_items, $text, $notification_link );
				}
			} else {
				$text = sprintf( __( 'You were promoted to a %s in the group "%s"', 'buddyboss' ), strtolower( get_group_role_label( $group_id, 'moderator_singular_label_name' ) ), $group->name );
				$notification_link = $group_link . '?n=1';

				if ( 'string' == $format ) {
					/**
					 * Filters single promoted to group mod notification for string format.
					 * Complete filter - bp_groups_single_member_promoted_to_mod_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param string $string            HTML anchor tag for notification.
					 * @param int    $group_link        The permalink for the group.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', '<a href="' . $notification_link . '">' . $text . '</a>', $group_link, $group->name, $text, $notification_link );
				} else {
					/**
					 * Filters single promoted to group admin notification for non-string format.
					 * Complete filter - bp_groups_single_member_promoted_to_mod_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param array  $array             Array holding permalink and content for notification.
					 * @param int    $group_link        The permalink for the group.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', array(
						'link' => $notification_link,
						'text' => $text
					), $group_link, $group->name, $text, $notification_link );
				}
			}

			break;

		case 'group_invite':
			$group_id = $item_id;
			$group = groups_get_group( $group_id );
			$group_link = bp_get_group_permalink( $group );
			$amount = 'single';

			$notification_link = bp_loggedin_user_domain() . bp_get_groups_slug() . '/invites/?n=1';

			if ( (int) $total_items > 1 ) {
				$text = sprintf( __( 'You have %d new group invitations', 'buddyboss' ), (int) $total_items );
				$amount = 'multiple';

				if ( 'string' == $format ) {
					/**
					 * Filters multiple group invitation notification for string format.
					 * Complete filter - bp_groups_multiple_group_invite_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param string $string            HTML anchor tag for notification.
					 * @param int    $total_items       Total number of rejected requests.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', '<a href="' . $notification_link . '">' . $text . '</a>', $total_items, $text, $notification_link );
				} else {
					/**
					 * Filters multiple group invitation notification for non-string format.
					 * Complete filter - bp_groups_multiple_group_invite_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param array  $array             Array holding permalink and content for notification.
					 * @param int    $total_items       Total number of rejected requests.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', array(
						'link' => $notification_link,
						'text' => $text
					), $total_items, $text, $notification_link );
				}
			} else {
				$text = sprintf( __( 'You have an invitation to the group: %s', 'buddyboss' ), $group->name );
				$filter = 'bp_groups_single_group_invite_notification';

				if ( 'string' == $format ) {
					/**
					 * Filters single group invitation notification for string format.
					 * Complete filter - bp_groups_single_group_invite_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param string $string            HTML anchor tag for notification.
					 * @param int    $group_link        The permalink for the group.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', '<a href="' . $notification_link . '">' . $text . '</a>', $group_link, $group->name, $text, $notification_link );
				} else {
					/**
					 * Filters single group invitation notification for non-string format.
					 * Complete filter - bp_groups_single_group_invite_notification.
					 *
					 * @since BuddyPress 1.0.0
					 *
					 * @param array  $array             Array holding permalink and content for notification.
					 * @param int    $group_link        The permalink for the group.
					 * @param string $group->name       Name of the group.
					 * @param string $text              Notification content.
					 * @param string $notification_link The permalink for notification.
					 */
					return apply_filters( 'bp_groups_' . $amount . '_' . $action . '_notification', array(
						'link' => $notification_link,
						'text' => $text
					), $group_link, $group->name, $text, $notification_link );
				}
			}

			break;

		default:

			/**
			 * Filters plugin-added group-related custom component_actions.
			 *
			 * @since BuddyPress 2.4.0
			 *
			 * @param string $notification      Null value.
			 * @param int    $item_id           The primary item ID.
			 * @param int    $secondary_item_id The secondary item ID.
			 * @param int    $total_items       The total number of messaging-related notifications
			 *                                  waiting for the user.
			 * @param string $format            'string' for BuddyBar-compatible notifications;
			 *                                  'array' for WP Toolbar.
			 */
			$custom_action_notification = apply_filters( 'bp_groups_' . $action . '_notification', null, $item_id, $secondary_item_id, $total_items, $format );

			if ( ! is_null( $custom_action_notification ) ) {
				return $custom_action_notification;
			}

			break;
	}

	/**
	 * Fires right before returning the formatted group notifications.
	 *
	 * @since BuddyPress 1.0.0
	 *
	 * @param string $action            The type of notification being rendered.
	 * @param int    $item_id           The primary item ID.
	 * @param int    $secondary_item_id The secondary item ID.
	 * @param int    $total_items       Total amount of items to format.
	 */
	do_action( 'groups_format_notifications', $action, $item_id, $secondary_item_id, $total_items );

	return false;
}