woocommerce-quantity-increment.php

<?php
/**
 * Plugin Name: WooCommerce Quantity Increment
 * Plugin URI: https://wordpress.org/plugins/woocommerce-quantity-increment/
 * Description: WooCommerce Quantity Increment adds JavaScript powered quantity buttons to your cart page.
 * Version: 1.1.0
 * Author: Automattic, WooThemes
 * Author URI: https://woocommerce.com/
 * Text Domain: woocommerce-quantity-increment
 * Domain Path: /languages
 */
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

if ( ! class_exists( 'WooCommerce_Quantity_Increment' ) ) {

	/**
	 * WooCommerce_Quantity_Increment main class.
	 */
	class WooCommerce_Quantity_Increment {

		/**
		 * Plugin version.
		 *
		 * @var string
		 */
		const VERSION = '1.1.0';

		/**
		 * Instance of this class.
		 *
		 * @var object
		 */
		protected static $instance = null;

		/**
		 * Initialize the plugin.
		 */
		private function __construct() {
			// Load plugin text domain
			add_action( 'init', array( $this, 'load_plugin_textdomain' ) );

			// Checks with WooCommerce is installed.
			if ( self::is_wc_version_gte_2_3() ) {
				add_action( 'wp_enqueue_scripts', array( $this, 'enqueue_scripts' ) );
			} else {
				add_action( 'admin_notices', array( $this, 'woocommerce_missing_notice' ) );
			}
		}

		/**
		 * Return an instance of this class.
		 *
		 * @return object A single instance of this class.
		 */
		public static function get_instance() {
			// If the single instance hasn't been set, set it now.
			if ( null == self::$instance ) {
				self::$instance = new self;
			}
			return self::$instance;
		}

		/**
		 * Load the plugin text domain for translation.
		 *
		 * @return void
		 */
		public function load_plugin_textdomain() {
			$locale = apply_filters( 'plugin_locale', get_locale(), 'woocommerce-quantity-increment' );
			load_textdomain( 'woocommerce-quantity-increment', trailingslashit( WP_LANG_DIR ) . 'woocommerce-quantity-increment/woocommerce-quantity-increment-' . $locale . '.mo' );
			load_plugin_textdomain( 'woocommerce-quantity-increment', false, dirname( plugin_basename( __FILE__ ) ) . '/languages/' );
		}

		/**
		 * Helper method to get the version of the currently installed WooCommerce
		 *
		 * @since 1.0.0
		 * @return string woocommerce version number or null
		 */
		private static function get_wc_version() {
			return defined( 'WC_VERSION' ) && WC_VERSION ? WC_VERSION : null;
		}

		/**
		 * Returns true if the installed version of WooCommerce is 2.3 or greater
		 *
		 * @since 1.0.0
		 * @return boolean true if the installed version of WooCommerce is 2.3 or greater
		 */
		public static function is_wc_version_gte_2_3() {
			return self::get_wc_version() && version_compare( self::get_wc_version(), '2.3', '>=' );
		}

		/**
		 * Enqueue scripts
		 */
		public function enqueue_scripts() {
			$min = defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG ? '' : '.min';
			wp_enqueue_script( 'wcqi-js', plugins_url( 'assets/js/wc-quantity-increment' . $min . '.js', __FILE__ ), array( 'jquery' ) );
			wp_enqueue_style( 'wcqi-css', plugins_url( 'assets/css/wc-quantity-increment.css', __FILE__ ) );
			wp_register_script( 'wcqi-number-polyfill', plugins_url( 'assets/js/lib/number-polyfill.min.js', __FILE__ ) );
		}

		/**
		 * WooCommerce fallback notice.
		 *
		 * @return string
		 */
		public function woocommerce_missing_notice() {
			echo '<div class="error"><p>' . sprintf( __( 'WooCommerce Quantity Increment requires the %s 2.3 or higher to work!', 'woocommerce-quantity-increment' ), '<a href="http://www.woothemes.com/woocommerce/" target="_blank">' . __( 'WooCommerce', 'woocommerce-quantity-increment' ) . '</a>' ) . '</p></div>';
		}

	}

	add_action( 'plugins_loaded', array( 'WooCommerce_Quantity_Increment', 'get_instance' ), 0 );
}