bbPress - send an auto-reply email to the bbPress topic author when a new topic is created

bbpress-auto-reply-email-on-new-topic.php

<?php
/**
 * Send an auto-reply email to the bbPress topic author when a new topic is created
 * @param		int $topic_id The ID of this topic
 * @param		object $topic The object of this topic
 * @return		mixed
 */
function kleo_bbp_email_new_topic( $topic_id = 0, $topic ) {
    // Bail if this isn't a topic
    if ( $topic->post_type != 'topic' ) {
        return;
    }

    $author_id = bbp_get_topic_author_id($topic_id);
    $author_name  = get_the_author_meta( 'display_name', $author_id );
    $author_email = get_the_author_meta( 'user_email', $author_id );
    $url = bbp_get_topic_permalink( $topic_id );

    $headers = array();
    $headers[] = 'Content-Type: text/html; charset=UTF-8';

    $to   = array();
    $to[] = $author_email;

    $message  = "Hello {$author_name},<br>";
    $message .= "This email is to alert you that your ticket titled <strong><a href='{$url}'>{$topic->post_title}</a></strong> has been created.<br><br>";
    $message .= "If you believe this is an error or you are still needing assistance with this issue please contact us. <br>";
    $message .= "Ticket URL: <a href='{$url}'>{$url}</a><br><br>";
    $message .= "-----------<br>Do not reply to this email!";

    wp_mail( $to, 'Your topic was successfully created', $message, $headers );
}
add_action( 'wp_insert_post', 'kleo_bbp_email_new_topic', 10, 2 );