BP_REST_Group_Membership_Endpoint::create_item( WP_REST_Request $request )

	public function create_item( $request ) {
		$user  = bp_rest_get_user( $request['user_id'] );
		$group = $this->groups_endpoint->get_group_object( $request['group_id'] );

		if ( ! $request['context'] || 'view' === $request['context'] ) {
			if ( ! groups_join_group( $group->id, $user->ID ) ) {
				return new WP_Error(
					'bp_rest_group_member_failed_to_join',
					__( 'Could not join the group.', 'buddyboss' ),
					array(
						'status' => 500,
					)
				);
			}

			// Get the group member.
			$group_member = new BP_Groups_Member( $user->ID, $group->id );
		} else {
			$role         = $request['role'];
			$group_id     = $group->id;
			$group_member = new BP_Groups_Member( $user->ID, $group_id );

			// Add member to the group.
			$group_member->group_id      = $group_id;
			$group_member->user_id       = $user->ID;
			$group_member->is_admin      = 0;
			$group_member->date_modified = bp_core_current_time();
			$group_member->is_confirmed  = 1;
			$saved                       = $group_member->save();

			if ( ! $saved ) {
				return new WP_Error(
					'bp_rest_group_member_failed_to_join',
					__( 'Could not add member to the group.', 'buddyboss' ),
					array(
						'status' => 500,
					)
				);
			}

			// If new role set, promote it too.
			if ( $saved && 'member' !== $role ) {
				// Make sure to update the group role.
				if ( groups_promote_member( $user->ID, $group_id, $role ) ) {
					$group_member = new BP_Groups_Member( $user->ID, $group_id );
				}
			}
		}

		// Setting context.
		$request->set_param( 'context', 'edit' );

		$retval = $this->prepare_response_for_collection(
			$this->prepare_item_for_response( $group_member, $request )
		);

		$response = rest_ensure_response( $retval );

		/**
		 * Fires after a member is added to a group via the REST API.
		 *
		 * @param WP_User $user The user.
		 * @param BP_Groups_Member $group_member The group member object.
		 * @param BP_Groups_Group $group The group object.
		 * @param WP_REST_Response $response The response data.
		 * @param WP_REST_Request $request The request sent to the API.
		 *
		 * @since 0.1.0
		 */
		do_action( 'bp_rest_group_members_create_item', $user, $group_member, $group, $response, $request );

		return $response;
	}