alphagateway.php

<?php
if (! defined('ABSPATH')) {
    exit(); // Exit if accessed directly
}

/*
 * Plugin Name: Alpha Bank gateway - WooCommerce Gateway
 * Plugin URI: https://github.com/Antreasgr/AlphaBankGatewayWooCommerce
 * Description: Extends WooCommerce by Adding custom gateway
 * Version: 1.0
 * Author: Antreas Gribas
 * Author URI: https://github.com/Antreasgr/
 */

// Include our Gateway Class and register Payment Gateway with WooCommerce
add_action('plugins_loaded', 'gateway_init', 0);

function gateway_init()
{
    // If the parent WC_Payment_Gateway class doesn't exist
    // it means WooCommerce is not installed on the site
    // so do nothing
    if (! class_exists('WC_Payment_Gateway'))
        return;

    // If we made it this far, then include our Gateway Class
    include_once ('alphagateway_class.php');
    include_once ('alphagatewaymasterpass_class.php');

    // Now that we have successfully included our class,
    // Lets add it too WooCommerce
    add_filter('woocommerce_payment_gateways', 'add_mygateway');

    function add_mygateway($methods)
    {
        $methods[] = 'WC_Gateway_Alpha';
        $methods[] = 'WC_Gateway_Alpha_Masterpass';
        return $methods;
    }
}