function bp_legacy_theme_new_activity_comment() {
	global $activities_template;

	$bp = buddypress();

	if ( ! bp_is_post_request() ) {
		return;
	}

	// Check the nonce.
	check_admin_referer( 'new_activity_comment', '_wpnonce_new_activity_comment' );

	if ( ! is_user_logged_in() ) {
		exit( '-1' );
	}

	$feedback = __( 'There was an error posting your reply. Please try again.', 'buddypress' );

	if ( empty( $_POST['content'] ) ) {
		exit( '-1<div id="message" class="error bp-ajax-message"><p>' . esc_html__( 'Please do not leave the comment area blank.', 'buddypress' ) . '</p></div>' );
	}

	if ( empty( $_POST['form_id'] ) || empty( $_POST['comment_id'] ) || ! is_numeric( $_POST['form_id'] ) || ! is_numeric( $_POST['comment_id'] ) ) {
		exit( '-1<div id="message" class="error bp-ajax-message"><p>' . esc_html( $feedback ) . '</p></div>' );
	}

	$activity_id   = (int) $_POST['form_id'];
	$activity_item = new BP_Activity_Activity( $activity_id );
	if ( ! bp_activity_user_can_read( $activity_item ) ) {
		exit( '-1<div id="message" class="error bp-ajax-message"><p>' . esc_html( $feedback ) . '</p></div>' );
	}

	$comment_id = bp_activity_new_comment( array(
		'activity_id' => $activity_id,
		'content'     => $_POST['content'],
		'parent_id'   => $_POST['comment_id'],
		'error_type'  => 'wp_error'
	) );

	if ( is_wp_error( $comment_id ) ) {
		exit( '-1<div id="message" class="error bp-ajax-message"><p>' . esc_html( $comment_id->get_error_message() ) . '</p></div>' );
	}

	// Load the new activity item into the $activities_template global.
	bp_has_activities( 'display_comments=stream&hide_spam=false&show_hidden=true&include=' . $comment_id );

	// Swap the current comment with the activity item we just loaded.
	if ( isset( $activities_template->activities[0] ) ) {
		$activities_template->activity = new stdClass();
		$activities_template->activity->id              = $activities_template->activities[0]->item_id;
		$activities_template->activity->current_comment = $activities_template->activities[0];

		// Because the whole tree has not been loaded, we manually
		// determine depth.
		$depth = 1;
		$parent_id = (int) $activities_template->activities[0]->secondary_item_id;
		while ( $parent_id !== (int) $activities_template->activities[0]->item_id ) {
			$depth++;
			$p_obj = new BP_Activity_Activity( $parent_id );
			$parent_id = (int) $p_obj->secondary_item_id;
		}
		$activities_template->activity->current_comment->depth = $depth;
	}

	// Get activity comment template part.
	bp_get_template_part( 'activity/comment' );

	unset( $activities_template );
	exit;
}