Appointments - Change Pending E-mail Body

appointments-change-pending-mail-body.php

<?php

/**
 * Plugin Name: Appointments - Change Pending E-mail Body
 * Plugin URI: https://premium.wpmudev.org/
 * Description: mu-plugin for changing the Appointments pending body message.
 * Version: 1.0.0
 * Author: Konstantinos Xenos @ WPMUDEV
 * Author URI: https://premium.wpmudev.org/
 * License: GPLv2 or later
 */

class Change_Pending_App_Notification {
	/**
	 * Constructor.
	 */
	public function __construct() {
		add_filter( 'app-messages-worker-notification', array( $this, 'change_email_body' ), 15, 3 );
		add_filter( 'app-messages-notification-body', array( $this, 'change_email_body' ), 15, 3 );
	}

	/**
	 * Change the body of the mail
	 *
	 * @param string $body The body of the e-mail.
	 * @param array  $r Request.
	 * @param int    $app_id The Application ID.
	 *
	 * @return string $new_body The new body of the e-mail.
	 */
	public function change_email_body( $body, $r, $app_id ) {
		add_filter( 'app-emails-content_type', array( $this, 'change_email_content_type' ) );

		$body  = '<p style="color:green;"><strong>New pending Appointment with ID ' . $app_id . '!</strong></p>';
		$body .= '<p>You can edit it clicking <a href="' . admin_url() . 'admin.php?page=appointments&type=pending">HERE</a></p>';

		return $body;
	}

	/**
	 * Changes the e-mail headers to text/html.
	 *
	 * @return string Header content type of text/html.
	 */
	public function change_email_content_type() {
		$content_type = 'text/html';

		return $content_type;
	}

}
new Change_Pending_App_Notification();