WooCommerce URL Coupons

url-coupons.js

$( document ).ready( function() {

	var cookie_name = 'dbrains-coupon';
	var cookie_name_error = 'dbrains-coupon-error';

	if ( 'undefined' === typeof $.cookie( cookie_name ) ) {
		return;
	}

	var message = 'The coupon code ' + $.cookie( cookie_name ).toUpperCase() + ' has been successfully applied.';
	var notice_class = 'dbrains-wc-coupons-notice';

	if ( 'undefined' !== typeof $.cookie( cookie_name_error ) ) {
		message = $.cookie( cookie_name_error );
		notice_class += ' error';
	}

	var $coupon_notice = $( '<div></div>', {
		'class': notice_class
	} );

	var $coupon_message = $( '<p></p>', {
		'class': 'dbrains-wc-coupons-notice-message'
	} );

	$coupon_message.html( message );
	$coupon_notice.prepend( $coupon_message )
	$( 'body' ).prepend( $coupon_notice );

	var coupon_height = $coupon_notice.outerHeight();
	$coupon_notice
		.css( 'margin-top', -1 * coupon_height )
		.show()
		.animate( { 'margin-top' : 0 }, 800 );

	setTimeout( function() {
		$coupon_notice
			.animate( { 'margin-top' : -1 * coupon_height }, 800, function() {
				$( this ).remove();
			} );
	}, 4000 );

	// clear the cookies
	$.removeCookie( cookie_name, { path: '/' } );
	$.removeCookie( cookie_name_error, { path: '/' } );

} );

url-coupons.php

<?php
class DBrains_URL_Coupons {

	protected $cookie_prefix = 'dbrains';
	protected $cookie_expires_in;

	protected $code;
	protected $error_messsage;

	function __construct() {
		$this->cookie_expires_in = DAY_IN_SECONDS;

		add_action( 'wp', array( $this, 'process_coupon' ), 1 );

		//add_filter( 'woocommerce_coupons_enabled', array( $this, 'remove_coupon_input_from_checkout' ) );
	}

	/**
	 * Set the coupon code
	 *
	 * @param string $code
	 */
	protected function set_code( $code ) {
		$this->code = strtolower( $code );
	}

	/**
	 * Get the name we are using for the cookie
	 *
	 * @return string
	 */
	protected function get_cookie_name() {
		return $this->cookie_prefix . '-coupon';
	}

	/**
	 * Get the name we are using for the error flag cookie
	 *
	 * @return string
	 */
	protected function get_cookie_name_error() {
		return $this->cookie_prefix . '-coupon-error';
	}

	/**
	 * Apply the coupon code to the WooCommerce cart
	 *
	 * @return bool
	 */
	protected function apply_coupon() {
		$coupon = new WC_Coupon( $this->code );

		// Since we're already displaying notices for adding the coupon,
		// we don't want any of them showing up on the checkout
		// so we save the notices and overwrite later
		$notices_before = wc_get_notices();

		if ( ! empty( $notices_before['error'] ) ) {
			$errors_before_count = count( $notices_before['error'] );
		}
		else {
			$errors_before_count = 0;
		}

		// If the cart is empty, the coupon code will succeed in being added but
		// will then disappear when they add an item to their cart
		$cart = WC()->cart->get_cart();
		if ( empty ( $cart ) ) {
			WC()->cart->add_to_cart( 21 );
		}

		$result = WC()->cart->add_discount( $coupon->code );

		$notices = wc_get_notices();

		WC()->session->set( 'wc_notices', $notices_before );

		if ( $result ) {
			return true;
		}

		$error_messages = array();
		for ( $i = $errors_before_count; $i < count( $notices['error'] ); $i++ ) {
			$error_messages[] = $notices['error'][$i];
		}

		return new WP_Error( 'apply_coupon_error', implode( ' ', $error_messages ) );
	}

	/**
	 * Clear the coupon cookies
	 */
	protected function clear_cookies() {
		setcookie( $this->get_cookie_name(), '', time() - $this->cookie_expires_in, COOKIEPATH, COOKIE_DOMAIN );
		setcookie( $this->get_cookie_name_error(), '', time() - $this->cookie_expires_in, COOKIEPATH, COOKIE_DOMAIN );
	}

	/**
	 * Handle the processing of the coupon and redirect of the page
	 */
	public function process_coupon() {

		if ( empty( $_GET['coupon'] ) ) {
			return;
		}

		if ( '{coupon}' == $_GET['coupon'] ) {
			wp_redirect( remove_query_arg( 'coupon' ) );
			exit;
		}

		$this->set_code( $_GET['coupon'] );

		$result = $this->apply_coupon();

		$this->clear_cookies();

		setcookie( $this->get_cookie_name(), $this->code, time() + $this->cookie_expires_in, COOKIEPATH, COOKIE_DOMAIN );

		if ( is_wp_error( $result ) ) {
			setcookie( $this->get_cookie_name_error(), $result->get_error_message(), time() + $this->cookie_expires_in, COOKIEPATH, COOKIE_DOMAIN );
		}

		$redirect_url = remove_query_arg( 'coupon' );

		wp_redirect( $redirect_url );
		exit;
	}

	/**
	 * Remove the coupon input from the checkout page
	 *
	 * @param bool $enable_coupons
	 *
	 * @return bool
	 */
	public function remove_coupon_input_from_checkout( $enable_coupons ) {
		if ( defined( 'DOING_AJAX' ) && DOING_AJAX ) {
			return $enable_coupons;
		}

		global $post;
		if ( isset( $post->ID ) && $post->ID === wc_get_page_id( 'checkout' ) ) {
			// we want to use coupons but just hide them on the checkout page
			return false;
		}

		return $enable_coupons;
	}
}

new DBrains_URL_Coupons();