Commerce partial payment : pay deposit at checkout and full settlement later

Question

In a Travel Booking website, how can I configure checkout so that customers pay only a n% deposit of the order total at checkout (off-site payment ATOS solution) ?

If the order is created :

• less than 30 days before departure, customer pay 100% of order total at checkout.
• between 30 and 90 days before, they pay 30% at checkout.
• more than 90 days before, they pay 10% at checkout.

Full settlement must be paid before travel departure (reminder emails)...

There are few contrib modules about deposit or partial payment :

• I had a look at Commerce deposit sandbox but it seems to be a per product solution, while I need a global cart approach.

• I began to hack Commerce Partial Payment for my own need. The module alters checkout_form_alter and provides a textfield where the customer can input a deposit value just before payment, so I pre-calculated deposit amount as per my rules above, filled the field with it, and hide it.

  /**
   * Implements hook_form_BASE_FORM_ID_alter().
   *
   * Alters whichever commerce checkout page includes the commerce_payment
   * checkout pane and adds the amount element to the payment details.
   */
  function commerce_partial_payment_form_commerce_checkout_form_alter(&$form, &$form_state, $form_id) {
  
    $panes = commerce_checkout_panes(array('pane_id' => 'commerce_payment'));
    $checkout_page = $panes['commerce_payment']['page'];
    if ($form_id != "commerce_checkout_form_$checkout_page" || !commerce_partial_payment_access($form_state['order'])) {
      return;
    }
  
    //setting up my own deposit value
    $deposit = vts_commerce_deposit();
  
    // If a values has already been set then use it as the value for the amount.
    // Otherwise, default it to the balance of the order.
    $default = NULL;
  
    if ($deposit > 0) {
       $default = $deposit ;
    }
    elseif (isset($form_state['values']['commerce_payment']['payment_details']['amount'])) {
      $default = $form_state['values']['commerce_payment']['payment_details']['amount'];
    }
    else {
      $balance = commerce_payment_order_balance($form_state['order']);
      $default = commerce_currency_amount_to_decimal($balance['amount'], $balance['currency_code']);
    }
  
    // Add the amount to the payment details form.
    $form['commerce_payment']['payment_details']['amount'] = array(
      '#type' => 'hidden',
      //'#title' => t('Amount'),
      '#weight' => -10,
      '#required' => TRUE,
      '#default_value' => $default,
    );
  }
  

But I got stuck there because that value, passed to $form['commerce_payment']['payment_details']['amount'], is not the one sent to the remote payment server (so that AFAIK, this module can't work)...

I also tried to set any other parts of checkout_form_alter ( $form and $form_state) where the order amount was repeated with $deposit, this NEVER changes the value set for payment at next step...

Question(s)

Using the above solution, at what point of checkout / which form can I alter the amount to be paid, replacing order total by deposit value ?

Indeed, I couldn't find how to separate the order total from the amount to pay... with correct data along the process : order total / paid deposit / balance order to pay later.

If there is a more D7 commerce way to implement this deposit issue, with rules or whatever, I'll be glad to learn it.

Answer 1

I got it working the following way.

• First install Commerce Partial Payment.
• Write a custom function to calculate deposit, MODULENAME_deposit_calculation

In order to get Commerce Deposit work with the deposit calculation you like to instead of a customer deposit input, patch it as following :

function commerce_partial_payment_form_commerce_checkout_form_alter(&$form, &$form_state, $form_id) {
  //... line 93
  $acompte = MODULENAME_deposit_calculation($form_state['order']) /100;
    if (!is_null($acompte) && $acompte > 0) {
      $default = $acompte;
    }
  //... line 109 Add the amount to the payment details form,in a hidden field.
  $form['commerce_payment']['payment_details']['amount'] = array(
    '#type' => 'hidden',
  //...
}

function commerce_partial_payment_checkout_validate($form, &$form_state, $checkout_pane, $order) {
  //... line 261
  $amount['amount'] = MODULENAME_deposit_calculation($order)  /100;
  //...
}

function commerce_partial_payment_checkout_submit($form, &$form_state, $checkout_pane, $order) {
  //...line 317
  if ($pane_values['payment_methods']) {
    $amount = MODULENAME_deposit_calculation($order) /100;
    $order->data['atos']['request']['amount'] = $amount;
    if (!empty( $amount)){
      $amount['amount'] = $amount;
  //...
}

As the sandbox doesn't properly send the deposit amount to off site payment, we need to hook the payment method :

In a METHOD_PAYMENT.api.php file

function hook_METHOD_PAYMENT_request_alter(&$settings) {
  //no example
}

Now send to off site payment the deposit amount instead of order total :

function commerce_partial_payment_PAYMENT_METHOD_request_alter(&$settings) {
  $order = commerce_order_load($settings['order_id']);
  $deposit = MODULENAME_deposit_calculation($order);
  $settings['amount'] = $deposit;
}

Last, add a price component deposit below Total to inform the customer what he's going to pay.

function commerce_partial_payment_commerce_price_formatted_components_alter(&$components, $price, $entity) {
  //Add a deposit line to price components
  $deposit= MODULENAME_deposit_calculation($entity);

  $components['deposit'] = array(
      'title' => t('Deposit'),
      'price' => array(
        'amount' => $deposit,
        'currency_code' => $components['commerce_price_formatted_amount']['price']['currency_code'],
        'data' => '',
      ),      
    'weight' => '200',
  );
}

Answer 2

I think that alter the form at checkout is not the place that interests your payment method ; only the total amount in the actual order is taken in account, imo.

So what you have to do is alter it at checkout form submit, either with custom module or rules.

The data taken in account is $order->commerce_order_total['und'][0]['amount']