bp_nouveau_ajax_post_update()

function bp_nouveau_ajax_post_update() {
	$bp = buddypress();

	if ( ! is_user_logged_in() || empty( $_POST['_wpnonce_post_update'] ) || ! wp_verify_nonce( $_POST['_wpnonce_post_update'], 'post_update' ) ) {
		wp_send_json_error();
	}

	if ( !strlen( trim( $_POST['content'] ) ) ) {

		// check activity toolbar options if one of them is set, activity can be empty
		$toolbar_option = false;
		if ( bp_is_active( 'media' ) && ! empty( $_POST['media'] ) ) {
			$toolbar_option = true;
		} else if ( bp_is_activity_link_preview_active() && ! empty( $_POST['link_url'] ) ) {
			$toolbar_option = true;
		} else if ( bp_is_active( 'media' ) && ! empty( $_POST['gif_data'] ) ) {
			$toolbar_option = true;
		}

		if ( ! $toolbar_option ) {
			wp_send_json_error(
				array(
					'message' => __( 'Please enter some content to post.', 'buddyboss' ),
				)
			);
		}
	}

	$activity_id = 0;
	$item_id     = 0;
	$object      = '';
	$is_private  = false;

	// Try to get the item id from posted variables.
	if ( ! empty( $_POST['item_id'] ) ) {
		$item_id = (int) $_POST['item_id'];
	}

	// Try to get the object from posted variables.
	if ( ! empty( $_POST['object'] ) ) {
		$object = sanitize_key( $_POST['object'] );

	// If the object is not set and we're in a group, set the item id and the object
	} elseif ( bp_is_group() ) {
		$item_id = bp_get_current_group_id();
		$object  = 'group';
		$status  = groups_get_current_group()->status;
	}

	if ( 'user' === $object && bp_is_active( 'activity' ) ) {
		$content = $_POST['content'];

        if ( ! empty( $_POST['user_id'] ) && bp_get_displayed_user() && $_POST['user_id'] != bp_get_displayed_user()->id ) {
			$content = sprintf('@%s %s', bp_get_displayed_user_mentionname(), $content);
        }

        $activity_id = bp_activity_post_update( array( 'content' => $content ) );

	} elseif ( 'group' === $object ) {
		if ( $item_id && bp_is_active( 'groups' ) ) {
			// This function is setting the current group!
			$activity_id = groups_post_update(
				array(
					'content'  => $_POST['content'],
					'group_id' => $item_id,
				)
			);

			if ( empty( $status ) ) {
				if ( ! empty( $bp->groups->current_group->status ) ) {
					$status = $bp->groups->current_group->status;
				} else {
					$group  = groups_get_group( array( 'group_id' => $group_id ) );
					$status = $group->status;
				}

				$is_private = 'public' !== $status;
			}
		}

	} else {
		/** This filter is documented in bp-activity/bp-activity-actions.php */
		$activity_id = apply_filters( 'bp_activity_custom_update', false, $object, $item_id, $_POST['content'] );
	}

	if ( empty( $activity_id ) ) {
		wp_send_json_error(
			array(
				'message' => __( 'There was a problem posting your update. Please try again.', 'buddyboss' ),
			)
		);
	}

	ob_start();
	if ( bp_has_activities( array( 'include' => $activity_id, 'show_hidden' => $is_private ) ) ) {
		while ( bp_activities() ) {
			bp_the_activity();
			bp_get_template_part( 'activity/entry' );
		}
	}
	$activity = ob_get_contents();
	ob_end_clean();

	wp_send_json_success( array(
		'id'           => $activity_id,
		'message'      => esc_html__( 'Update posted.', 'buddyboss' ) . ' ' . sprintf( '<a href="%s" class="just-posted">%s</a>', esc_url( bp_activity_get_permalink( $activity_id ) ), esc_html__( 'View activity.', 'buddyboss' ) ),
		'activity'     => $activity,

		/**
		 * Filters whether or not an AJAX post update is private.
		 *
		 * @since BuddyPress 3.0.0
		 *
		 * @param string/bool $is_private Privacy status for the update.
		 */
		'is_private'   => apply_filters( 'bp_nouveau_ajax_post_update_is_private', $is_private ),
		'is_directory' => bp_is_activity_directory(),
	) );
}