<p>
  You'll be redirected to Adyen Hosted Payment Pages. After completing the
  payment form you'll be back to the store.
</p>

<%= link_to "Pay with Adyen", ::Adyen::Form.redirect_url(
        :currency_code => Spree::Config.currency,
        # :merchantReturnData => payment_method.id,
        :ship_before_date => Date.tomorrow,
        :session_validity => 10.minutes.from_now,
        :recurring => false,
        :merchant_reference => "#{@order.number}",
        :merchant_account => payment_method.preferred_merchant_account,
        :skin_code => payment_method.preferred_skin_code,
        :shared_secret => payment_method.preferred_shared_secret,
        :payment_amount => (@order.total.to_f * 100).to_int
      )
%>

<p>
  You'll be redirected to Adyen Hosted Payment Pages. After completing the
  payment form you'll be back to the store.
</p>

<%= link_to "Pay with Adyen", ::Adyen::Form.redirect_url(
        :currency_code => Spree::Config.currency,
        # :merchantReturnData => payment_method.id,
        :ship_before_date => Date.tomorrow,
        :session_validity => 10.minutes.from_now,
        :recurring => false,
        :merchant_reference => "#{@order.number}",
        :merchant_account => payment_method.preferred_merchant_account,
        :skin_code => payment_method.preferred_skin_code,
        :shared_secret => payment_method.preferred_shared_secret,
        :payment_amount => (@order.total.to_f * 100).to_int
      )
%>

<script type="text/javascript">
$(function() {
  var spreePaymentRadio = $("#checkout_form_payment input:radio")

  spreePaymentRadio.change(function() {
    if ($("#checkout_form_payment input:radio:checked").val() == <%= payment_method.id %>) {
      $("#checkout_form_payment .form-buttons").hide();
    } else {
      $("#checkout_form_payment .form-buttons").show();
    }
  });
});
</script>

Hide checkout Save and Continue button for AdyenHPP
Hide checkout Save and Continue button for AdyenHPP

Users shouldn't be able to advance checkout using that button because
for AdyenHPP payment must be done outside of the store
