Wordpress woocommerce function to add product to cart then apply coupon then redirect not working

I'm trying to get it so that when a user visits a certain page, a specific product is added to cart, a coupon is applied, and then they are redirected to the checkout page.

This is the code I have so far, which I've added to functions.php:

function add_product_to_cart() {
  $found = false;
  if ( sizeof( WC()->cart->get_cart() ) > 0 ) {
      foreach ( WC()->cart->get_cart() as $cart_item_key => $values ) {
        $_product = $values['data'];
        if ( $_product->id == $product_id )
              $found = true;
    }
    if ( ! $found )
        WC()->cart->add_to_cart( $product_id = 8, $quantity = 1, $variation_id = 15 );
    } else {
        WC()->cart->add_to_cart( $product_id = 8, $quantity = 1, $variation_id = 15 );
    }
}

function apply_matched_coupons() {
   global $woocommerce; 
   $coupon_code = 'couponcodehere'; 

   if ( $woocommerce->cart->has_discount( $coupon_code ) ) {
    return;
   }
   foreach ($woocommerce->cart->cart_contents as $key => $values ) {

   $autocoupon = array(8);

   if(in_array($values['product_id'],$autocoupon)){    
       $woocommerce->cart->add_discount( $coupon_code );
       wc_print_notices();
   }
   }
}

add_action( 'certain_page_redirect', 'add_product_coupon_redirect' );
function add_product_coupon_redirect() {
        if( is_page('5') ) {
            add_action( 'add_specific_product', 'add_product_to_cart' );
            add_action( 'woocommerce_add_coupon', 'apply_matched_coupons' );
            wp_redirect('http://ift.tt/2168d3f');
            exit;
         }
}

Nothing seems to be working. I just can't get this to work. (Note I'm a relative beginner with php.) Any thoughts?

via Chebli Mohamed