<?php

/**
 * @file
 * Defines the credit card payment method and hooks in payment gateways.
 */


/** Just authorize an amount on a credit card account. */
define('UC_CREDIT_AUTH_ONLY', 'authorize');

/** Capture funds from a prior authorization. */
define('UC_CREDIT_PRIOR_AUTH_CAPTURE', 'prior_auth_capture');

/** Authorize and capture money all at once. */
define('UC_CREDIT_AUTH_CAPTURE', 'auth_capture');

/** Set up a credit card reference through the payment gateway. */
define('UC_CREDIT_REFERENCE_SET', 'reference_set');

/** Capture funds using a credit card reference. */
define('UC_CREDIT_REFERENCE_TXN', 'reference_txn');

/** Remove a reference from the payment gateway. */
define('UC_CREDIT_REFERENCE_REMOVE', 'reference_remove');

/** Credit funds to a reference at the payment gateway. */
define('UC_CREDIT_REFERENCE_CREDIT', 'reference_credit');

/** Credit funds to a credit card account. */
define('UC_CREDIT_CREDIT', 'credit');

/** Void a transaction before the transaction clears. */
define('UC_CREDIT_VOID', 'void');


/** Name of encryption key file. */
define('UC_CREDIT_KEYFILE_NAME', 'uc_credit.key');


/**
 * Implements hook_help().
 */
function uc_credit_help($path, $arg) {
  switch ($path) {
    case 'admin/store/orders/%/credit':
      return '<p>' . t('Use this terminal to process credit card payments through your default gateway.') . '</p>';
  }
}

/**
 * Implements hook_menu().
 */
function uc_credit_menu() {
  $items['cart/checkout/credit/cvv_info'] = array(
    'title' => 'CVV information',
    'page callback' => 'uc_credit_cvv_info',
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
    'file' => 'uc_credit.pages.inc',
  );
  $items['admin/store/orders/%uc_order/credit'] = array(
    'title callback' => 'uc_credit_terminal_title',
    'title arguments' => array(3),
    'description' => 'Displays a form to process a credit card payment.',
    'page callback' => 'uc_credit_terminal',
    'page arguments' => array(3),
    'access arguments' => array('process credit cards'),
    'file' => 'uc_credit.admin.inc',
  );

  return $items;
}

/**
 * Implements hook_permission().
 */
function uc_credit_permission() {
  return array(
    'administer credit cards' => array(
      'title' => t('Administer credit cards'),
    ),
    'process credit cards' => array(
      'title' => t('Process credit cards'),
    ),
    'view cc details' => array(
      'title' => t('View credit card details'),
    ),
  );
}

/**
 * Implements hook_theme().
 */
function uc_credit_theme() {
  return array(
    'uc_credit_cvv_help' => array(
      'file' => 'uc_credit.theme.inc',
    ),
  );
}

/**
 * Implements hook_init().
 */
function uc_credit_init() {
  global $conf;
  $conf['i18n_variables'][] = 'uc_credit_fail_message';
  $conf['i18n_variables'][] = 'uc_credit_policy';
}

/**
 * Implements hook_form_FORM_ID_alter() for uc_cart_checkout_form().
 */
function uc_credit_form_uc_cart_checkout_form_alter(&$form, &$form_state) {
  // Cache the CC details for use in other functions.
  if (isset($_SESSION['sescrd'])) {
    uc_credit_cache('save', $_SESSION['sescrd']);

    // Store the encrypted details to the form for processing on submit.
    $form['payment_details_data'] = array(
      '#type' => 'hidden',
      '#value' => $_SESSION['sescrd'],
    );

    // Clear the session of the details.
    unset($_SESSION['sescrd']);
  }
  unset($_SESSION['cc_pay']);
}

/**
 * Implements hook_form_FORM_ID_alter() for uc_cart_checkout_review_form().
 */
function uc_credit_form_uc_cart_checkout_review_form_alter(&$form, &$form_state) {
  // Check if the customer paid by CC and refreshed on the review page.
  if (isset($_SESSION['cc_pay']) && !isset($_SESSION['sescrd']) && empty($_POST['sescrd'])) {
    // Send them back to the checkout form to put in their details again.
    drupal_set_message(t('To protect our customers from identity theft, credit card details are erased when a browser refreshes on the checkout review page.  Please enter your card details again and re-submit the form.'), 'error');

    $_SESSION['clear_cc'] = TRUE;
    unset($_SESSION['cc_pay']);
    drupal_goto('cart/checkout');
  }

  if (isset($_SESSION['sescrd'])) {
    // Cache the CC details for use in other functions.
    uc_credit_cache('save', $_SESSION['sescrd']);

    // Store the encrypted details to the form for processing on submit.
    $form['sescrd'] = array(
      '#type' => 'hidden',
      '#value' => base64_encode($_SESSION['sescrd']),
    );
  }
  else {
    $form['sescrd'] = array(
      '#type' => 'hidden',
      '#value' => '',
    );
  }

  // Add submit handler to preserve CC details for the back button and
  // failed order submissions.
  $form['actions']['back']['#submit'][] = 'uc_credit_cart_review_back_submit';

  // Reconstruct the submit handler array for before and after processing.
  $submit = array_merge(array('uc_credit_cart_review_pre_form_submit'), $form['#submit']);
  $submit[] = 'uc_credit_cart_review_post_form_submit';

  $form['#submit'] = $submit;

  // Clear the session of the details.
  unset($_SESSION['sescrd']);
}

/**
 * Implements hook_exit().
 */
function uc_credit_exit() {
  // Make sure sensitive checkout session data doesn't persist on other pages.
  if (isset($_SESSION['sescrd'])) {
    if (isset($_GET['q'])) {
      // Separate the args ourself since the arg() function may not be loaded.
      $args = explode('/', $_GET['q']);
      if (!isset($args[1]) || $args[1] != 'checkout') {
        unset($_SESSION['sescrd']);
      }
    }
    else {
      unset($_SESSION['sescrd']);
    }
  }
}

/**
 * Implements hook_uc_store_status().
 */
function uc_credit_uc_store_status() {
  // Throw up an error row if encryption has not been set up yet.
  if ($key = uc_credit_encryption_key()) {
    $statuses[] = array(
      'status' => 'ok',
      'title' => t('Credit card encryption'),
      'desc' => t('Credit card data is encrypted during checkout for maximum security.'),
    );
  }
  else {
    $statuses[] = array(
      'status' => 'error',
      'title' => t('Credit card encryption'),
      'desc' => t('You must review your <a href="!url">credit card security settings</a> and enable encryption before you can accept credit card payments.', array('!url' => url('admin/store/settings/payment/method/credit'))),
    );
  }

  return $statuses;
}

/**
 * Implements hook_uc_order().
 */
function uc_credit_uc_order($op, $order, $arg2) {
  // Set up the encryption key and object for saving and loading.
  if (isset($order->payment_method) && $order->payment_method == 'credit' && ($op == 'save' || $op == 'load')) {
    // Log an error if encryption isn't configured properly.
    if (!uc_credit_encryption_key()) {
      watchdog('uc_credit', 'Credit card encryption must be set up to process credit cards.');
    }
  }

  switch ($op) {
    case 'submit':
      if (isset($order->payment_method) && $order->payment_method == 'credit') {
        // Clear out that session variable denoting this as a CC paid order.
        unset($_SESSION['cc_pay']);

        // Process CC transactions when an order is submitted after review.
        $gateway_id = uc_credit_default_gateway();
        $data = array(
          'txn_type' => variable_get('uc_pg_' . $gateway_id . '_cc_txn_type', UC_CREDIT_AUTH_CAPTURE),
        );

        // Attempt to process the CC payment.
        $order->payment_details = uc_credit_cache('load');
        $pass = uc_payment_process_payment('credit', $order->order_id, $order->order_total, $data, TRUE, NULL, FALSE);

        // If the payment failed, store the data back in the session and
        // halt the checkout process.
        if (!$pass) {
          $message = variable_get('uc_credit_fail_message', t('We were unable to process your credit card payment. Please verify your details and try again.  If the problem persists, contact us to complete your order.'));
          return array(array('pass' => FALSE, 'message' => $message));
        }
      }
      break;

    case 'save':
      if (isset($order->payment_method) && $order->payment_method == 'credit' && !empty($order->payment_details)) {
        _uc_credit_save_cc_data_to_order($order->payment_details, $order->order_id);
      }
      break;

    case 'load':
      if (isset($order->payment_method) && $order->payment_method == 'credit') {
        // Load the CC details from the credit cache if available.
        $order->payment_details = uc_credit_cache('load');

        // Otherwise load any details that might be stored in the data array.
        if (empty($order->payment_details) && isset($order->data['cc_data'])) {
          $order->payment_details = uc_credit_cache('save', $order->data['cc_data']);
        }
      }
      break;
  }
}

/**
 * Implements hook_uc_payment_method().
 */
function uc_credit_uc_payment_method() {
  if (arg(0) == 'cart' && uc_credit_encryption_key() === FALSE) {
    return;
  }

  $path = base_path() . drupal_get_path('module', 'uc_credit');
  $title = t('Credit card:');
  $cc_types = array('visa', 'mastercard', 'discover', 'amex');
  foreach ($cc_types as $type) {
    if (variable_get('uc_credit_' . $type, TRUE)) {
      $title .= ' ' . theme('image', array(
        'path' => drupal_get_path('module', 'uc_credit') . '/images/' . $type . '.gif',
        'attributes' => array('class' => array('uc-credit-cctype', 'uc-credit-cctype-' . $type)),
      ));
    }
  }
  $methods['credit'] = array(
    'name' => t('Credit card'),
    'title' => $title,
    'desc' => t('Pay by credit card.'),
    'callback' => 'uc_payment_method_credit',
    'weight' => 2,
    'checkout' => TRUE,
  );

  return $methods;
}

/**
 * Callback function for the Credit Card payment method.
 */
function uc_payment_method_credit($op, &$order, $form = NULL, &$form_state = NULL) {
  switch ($op) {
    case 'cart-details':
      $details = uc_payment_method_credit_form(array(), $form_state, $order);
      return $details;

    case 'cart-process':
      if (!isset($form_state['values']['panes']['payment']['details']['cc_number'])) {
        return;
      }
      // Fetch the CC details from the $_POST directly.
      $cc_data = $form_state['values']['panes']['payment']['details'];

      $cc_data['cc_number'] = str_replace(' ', '', $cc_data['cc_number']);

      array_walk($cc_data, 'check_plain');

      // Recover cached CC data in
      // $form_state['values']['panes']['payment']['details'] if it exists.
      if (isset($form_state['values']['panes']['payment']['details']['payment_details_data'])) {
        $cache = uc_credit_cache('save', $form_state['values']['panes']['payment']['details']['payment_details_data']);
      }

      // Account for partial CC numbers when masked by the system.
      if (substr($cc_data['cc_number'], 0, strlen(t('(Last4)'))) == t('(Last4)')) {
        // Recover the number from the encrypted data in the form if truncated.
        if (isset($cache['cc_number'])) {
          $cc_data['cc_number'] = $cache['cc_number'];
        }
        else {
          $cc_data['cc_number'] = '';
        }
      }

      // Account for masked CVV numbers.
      if (!empty($cc_data['cc_cvv']) && $cc_data['cc_cvv'] == str_repeat('-', strlen($cc_data['cc_cvv']))) {
        // Recover the number from the encrypted data in $_POST if truncated.
        if (isset($cache['cc_cvv'])) {
          $cc_data['cc_cvv'] = $cache['cc_cvv'];
        }
        else {
          $cc_data['cc_cvv'] = '';
        }
      }

      // Go ahead and put the CC data in the payment details array.
      $order->payment_details = $cc_data;

      // Default our value for validation.
      $return = TRUE;

      // Make sure an owner value was entered.
      if (variable_get('uc_credit_owner_enabled', FALSE) && empty($cc_data['cc_owner'])) {
        form_set_error('panes][payment][details][cc_owner', t('Enter the owner name as it appears on the card.'));
        $return = FALSE;
      }

      // Validate the CC number if that's turned on/check for non-digits.
      if ((variable_get('uc_credit_validate_numbers', TRUE) && !_uc_credit_valid_card_number($cc_data['cc_number']))
        || !ctype_digit($cc_data['cc_number'])) {
        form_set_error('panes][payment][details][cc_number', t('You have entered an invalid credit card number.'));
        $return = FALSE;
      }

      // Validate the start date (if entered).
      if (variable_get('uc_credit_start_enabled', FALSE) && !_uc_credit_valid_card_start($cc_data['cc_start_month'], $cc_data['cc_start_year'])) {
        form_set_error('panes][payment][details][cc_start_month', t('The start date you entered is invalid.'));
        form_set_error('panes][payment][details][cc_start_year');
        $return = FALSE;
      }

      // Validate the card expiration date.
      if (!_uc_credit_valid_card_expiration($cc_data['cc_exp_month'], $cc_data['cc_exp_year'])) {
        form_set_error('panes][payment][details][cc_exp_month', t('The credit card you entered has expired.'));
        form_set_error('panes][payment][details][cc_exp_year');
        $return = FALSE;
      }

      // Validate the issue number (if entered).  With issue numbers, '01' is
      // different from '1', but is_numeric() is still appropriate.
      if (variable_get('uc_credit_issue_enabled', FALSE) && !_uc_credit_valid_card_issue($cc_data['cc_issue'])) {
        form_set_error('panes][payment][details][cc_issue', t('The issue number you entered is invalid.'));
        $return = FALSE;
      }

      // Validate the CVV number if enabled.
      if (variable_get('uc_credit_cvv_enabled', TRUE) && !_uc_credit_valid_cvv($cc_data['cc_cvv'])) {
        form_set_error('panes][payment][details][cc_cvv', t('You have entered an invalid CVV number.'));
        $return = FALSE;
      }

      // Validate the bank name if enabled.
      if (variable_get('uc_credit_bank_enabled', FALSE) && empty($cc_data['cc_bank'])) {
        form_set_error('panes][payment][details][cc_bank', t('You must enter the issuing bank for that card.'));
        $return = FALSE;
      }

      // Initialize the encryption key and class.
      $key = uc_credit_encryption_key();
      $crypt = new UbercartEncryption();

      // Store the encrypted details in the session for the next pageload.
      // We are using base64_encode() because the encrypt function works with a
      // limited set of characters, not supporting the full Unicode character
      // set or even extended ASCII characters that may be present.
      // base64_encode() converts everything to a subset of ASCII, ensuring that
      // the encryption algorithm does not mangle names.
      $_SESSION['sescrd'] = $crypt->encrypt($key, base64_encode(serialize($order->payment_details)));

      // Log any errors to the watchdog.
      uc_store_encryption_errors($crypt, 'uc_credit');

      // If we're going to the review screen, set a variable that lets us know
      // we're paying by CC.
      if ($return) {
        $_SESSION['cc_pay'] = TRUE;
      }

      return $return;

    case 'cart-review':
      if (variable_get('uc_credit_type_enabled', FALSE)) {
        $review[] = array('title' => t('Card type'), 'data' => check_plain($order->payment_details['cc_type']));
      }
      if (variable_get('uc_credit_owner_enabled', FALSE)) {
        $review[] = array('title' => t('Card owner'), 'data' => check_plain($order->payment_details['cc_owner']));
      }
      $review[] = array('title' => t('Card number'), 'data' => uc_credit_display_number($order->payment_details['cc_number']));
      if (variable_get('uc_credit_start_enabled', FALSE)) {
        $start = $order->payment_details['cc_start_month'] . '/' . $order->payment_details['cc_start_year'];
        $review[] = array('title' => t('Start date'), 'data' => strlen($start) > 1 ? $start : '');
      }
      $review[] = array('title' => t('Expiration'), 'data' => $order->payment_details['cc_exp_month'] . '/' . $order->payment_details['cc_exp_year']);
      if (variable_get('uc_credit_issue_enabled', FALSE)) {
        $review[] = array('title' => t('Issue number'), 'data' => $order->payment_details['cc_issue']);
      }
      if (variable_get('uc_credit_bank_enabled', FALSE)) {
        $review[] = array('title' => t('Issuing bank'), 'data' => check_plain($order->payment_details['cc_bank']));
      }
      return $review;

    case 'order-view':
      $build = array();

      // Add the hidden span for the CC details if possible.
      if (user_access('view cc details')) {
        $rows = array();

        if (!empty($order->payment_details['cc_type'])) {
          $rows[] = t('Card type') . ': ' . check_plain($order->payment_details['cc_type']);
        }

        if (!empty($order->payment_details['cc_owner'])) {
          $rows[] = t('Card owner') . ': ' . check_plain($order->payment_details['cc_owner']);
        }

        $rows[] = t('Card number') . ': ' . uc_credit_display_number($order->payment_details['cc_number']);

        if (!empty($order->payment_details['cc_start_month']) && !empty($order->payment_details['cc_start_year'])) {
          $rows[] = t('Start date') . ': ' . $order->payment_details['cc_start_month'] . '/' . $order->payment_details['cc_start_year'];
        }

        if (!empty($order->payment_details['cc_exp_month']) && !empty($order->payment_details['cc_exp_year'])) {
          $rows[] = t('Expiration') . ': ' . $order->payment_details['cc_exp_month'] . '/' . $order->payment_details['cc_exp_year'];
        }

        if (!empty($order->payment_details['cc_issue'])) {
          $rows[] = t('Issue number') . ': ' . check_plain($order->payment_details['cc_issue']);
        }

        if (!empty($order->payment_details['cc_bank'])) {
          $rows[] = t('Issuing bank') . ': ' . check_plain($order->payment_details['cc_bank']);
        }

        $build['cc_info'] = array(
          '#prefix' => '<a href="#" onclick="jQuery(this).hide().next().show();">' . t('Show card details') . '</a><div style="display: none;">',
          '#markup' => implode('<br />', $rows),
          '#suffix' => '</div>',
        );

        // Add the form to process the card if applicable.
        if (user_access('process credit cards')) {
          $build['terminal'] = drupal_get_form('uc_credit_order_view_form', $order->order_id);
        }
      }

      return $build;

    case 'customer-view':
      $build['#markup'] = t('Card number') . ':<br />'
        . uc_credit_display_number($order->payment_details['cc_number']);

      return $build;

    case 'order-details':
      return t('Use the terminal available through the<br />%button button on the View tab to<br />process credit card payments.', array('%button' => t('Process card')));

    case 'settings':
      form_load_include($form_state, 'inc', 'uc_credit', 'uc_credit.admin');
      return uc_credit_settings_form($form, $form_state);
  }
}

/**
 * Displays the credit card details form on the checkout screen.
 */
function uc_payment_method_credit_form($form, &$form_state, $order) {
  // Normally the CC data is posted in via AJAX.
  if (!empty($form_state['values']['payment_details_data']) && arg(0) == 'cart') {
    $order->payment_details = uc_credit_cache('save', $form_state['values']['payment_details_data']);
  }

  // But we have to accommodate failed checkout form validation here.
  if (isset($_SESSION['sescrd'])) {
    $order->payment_details = uc_credit_cache('save', $_SESSION['sescrd']);
    unset($_SESSION['sescrd']);
  }

  if (!isset($order->payment_details) && isset($form_state['values']['panes']['payment']['details'])) {
    $order->payment_details = $form_state['values']['panes']['payment']['details'];
    $order->payment_details['cc_number'] = str_replace(' ', '', $order->payment_details['cc_number']);
  }

  if (!isset($order->payment_details)) {
    $order->payment_details = array();
  }

  $form['cc_policy'] = array(
    '#markup' => '<p>' . variable_get('uc_credit_policy', t('Your billing information must match the billing address for the credit card entered below or we will be unable to process your payment.')) . '</p>'
  );

  $types = variable_get('uc_credit_accepted_types', implode("\r\n", array(t('Visa'), t('Mastercard'), t('Discover'), t('American Express'))));
  if (variable_get('uc_credit_type_enabled', FALSE) && $types) {
    $form['cc_type'] = array(
      '#type' => 'select',
      '#title' => t('Card type'),
      '#options' => drupal_map_assoc(explode("\r\n", $types)),
      '#default_value' => isset($order->payment_details['cc_type']) ? $order->payment_details['cc_type'] : NULL,
    );
  }

  if (variable_get('uc_credit_owner_enabled', FALSE)) {
    $form['cc_owner'] = array(
      '#type' => 'textfield',
      '#title' => t('Card owner'),
      '#default_value' => isset($order->payment_details['cc_owner']) ? $order->payment_details['cc_owner'] : '',
      '#attributes' => array('autocomplete' => 'off'),
      '#size' => 32,
      '#maxlength' => 64,
    );
  }

  // Set up the default CC number on the credit card form.
  if (isset($_SESSION['clear_cc']) || !isset($order->payment_details['cc_number'])) {
    $default_num = NULL;
  }
  elseif (variable_get('uc_credit_validate_numbers', TRUE) && !_uc_credit_valid_card_number($order->payment_details['cc_number'])) {
    // Display the number as is if it does not validate so it can be corrected.
    $default_num = $order->payment_details['cc_number'];
  }
  else {
    // Otherwise default to the last 4 digits.
    $default_num = t('(Last 4) ') . substr($order->payment_details['cc_number'], -4);
  }

  $form['cc_number'] = array(
    '#type' => 'textfield',
    '#title' => t('Card number'),
    '#default_value' => $default_num,
    '#attributes' => array('autocomplete' => 'off'),
    '#size' => 20,
    '#maxlength' => 19,
  );

  if (variable_get('uc_credit_start_enabled', FALSE)) {
    $month = isset($order->payment_details['cc_start_month']) ? $order->payment_details['cc_start_month'] : NULL;
    $year = isset($order->payment_details['cc_start_year']) ? $order->payment_details['cc_start_year'] : NULL;
    $form['cc_start_month'] = uc_select_month(t('Start date'), $month, TRUE);
    $form['cc_start_year'] = uc_select_year(t('Start year'), $year, date('Y') - 10, date('Y'), TRUE);
    $form['cc_start_year']['#field_suffix'] = t('(if present)');
  }

  $month = isset($order->payment_details['cc_exp_month']) ? $order->payment_details['cc_exp_month'] : 1;
  $year = isset($order->payment_details['cc_exp_year']) ? $order->payment_details['cc_exp_year'] : date('Y');
  $form['cc_exp_month'] = uc_select_month(t('Expiration date'), $month);
  $form['cc_exp_year'] = uc_select_year(t('Expiration year'), $year);

  if (variable_get('uc_credit_issue_enabled', FALSE)) {
    // Set up the default Issue Number on the credit card form.
    if (empty($order->payment_details['cc_issue'])) {
      $default_card_issue = NULL;
    }
    elseif (!_uc_credit_valid_card_issue($order->payment_details['cc_issue'])) {
      // Display the Issue Number as is if it does not validate so it can be
      // corrected.
      $default_card_issue = $order->payment_details['cc_issue'];
    }
    else {
      // Otherwise mask it with dashes.
      $default_card_issue = str_repeat('-', strlen($order->payment_details['cc_issue']));
    }

    $form['cc_issue'] = array(
      '#type' => 'textfield',
      '#title' => t('Issue number'),
      '#default_value' => $default_card_issue,
      '#attributes' => array('autocomplete' => 'off'),
      '#size' => 2,
      '#maxlength' => 2,
      '#field_suffix' => t('(if present)'),
    );
  }

  if (variable_get('uc_credit_cvv_enabled', TRUE)) {
    // Set up the default CVV  on the credit card form.
    if (isset($_SESSION['clear_cc']) || empty($order->payment_details['cc_cvv'])) {
      $default_cvv = NULL;
    }
    elseif (!_uc_credit_valid_cvv($order->payment_details['cc_cvv'])) {
      // Display the CVV as is if it does not validate so it can be corrected.
      $default_cvv = $order->payment_details['cc_cvv'];
    }
    else {
      // Otherwise mask it with dashes.
      $default_cvv = str_repeat('-', strlen($order->payment_details['cc_cvv']));
    }

    $form['cc_cvv'] = array(
      '#type' => 'textfield',
      '#title' => t('CVV'),
      '#default_value' => $default_cvv,
      '#attributes' => array('autocomplete' => 'off'),
      '#size' => variable_get('uc_credit_amex', TRUE) ? 4 : 3,
      '#maxlength' => variable_get('uc_credit_amex', TRUE) ? 4 : 3,
      '#field_suffix' => theme('uc_credit_cvv_help'),
    );
  }

  if (variable_get('uc_credit_bank_enabled', FALSE)) {
    $form['cc_bank'] = array(
      '#type' => 'textfield',
      '#title' => t('Issuing bank'),
      '#default_value' => isset($order->payment_details['cc_bank']) ? $order->payment_details['cc_bank'] : '',
      '#attributes' => array('autocomplete' => 'off'),
      '#size' => 32,
      '#maxlength' => 64,
    );
  }

  unset($_SESSION['clear_cc']);

  return $form;
}

/**
 * Builds the "Process Card" button on the order view.
 *
 * @see uc_credit_order_view_form_submit()
 */
function uc_credit_order_view_form($form, &$form_state, $order_id) {
  $form['order_id'] = array(
    '#type' => 'hidden',
    '#value' => $order_id,
  );
  $form['actions'] = array('#type' => 'actions');
  $form['actions']['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Process card'),
  );
  return $form;
}

/**
 * Submit handler for order view form.
 *
 * @see uc_credit_order_view_form()
 */
function uc_credit_order_view_form_submit($form, &$form_state) {
  $form_state['redirect'] = 'admin/store/orders/' . $form_state['values']['order_id'] . '/credit';
}

/**
 * Returns a credit card number with appropriate masking.
 */
function uc_credit_display_number($number) {
  if (strlen($number) == 4) {
    return t('(Last 4) ') . $number;
  }

  return str_repeat('-', 12) . substr($number, -4);
}

/**
 * Caches CC details on a pageload for use in various functions.
 *
 * @param $op
 *   The cache operation to perform; either 'save', 'load', or 'clear'.
 * @param $data
 *   The encrypted, serialized string containing the CC data.
 *
 * @return
 *   An array of credit card details.
 */
function uc_credit_cache($op, $data = NULL, $encrypted = TRUE) {
  // The CC data will be stored in this static variable.
  static $cc_cache = array();

  if ($op == 'save') {
    if ($encrypted) {
      // Initialize the encryption key and class.
      $key = uc_credit_encryption_key();
      $crypt = new UbercartEncryption();

      // Save the unencrypted CC details for the duration of this request.
      // In recent versions, we base64_encode() the payment details before
      // encrypting. We can detect encoded data by the lack of colons,
      // due to base64's limited character set.
      $data = $crypt->decrypt($key, $data);
      if (strpos($data, ':') === FALSE) {
        $data = base64_decode($data);
      }
      $cc_cache = @unserialize($data);
    }
    else {
      $cc_cache = $data;
    }
  }
  elseif ($op == 'clear') {
    $cc_cache = array();
  }

  return $cc_cache;
}

/**
 * Caches the encrypted CC data on the review order form for processing.
 */
function uc_credit_cart_review_back_submit($form, &$form_state) {
  $session_card_data = base64_decode($_POST['sescrd']);

  $_SESSION['sescrd'] = $session_card_data;
  uc_credit_cache('save', $session_card_data);
}

/**
 * Caches the encrypted CC data on the review order form for processing.
 */
function uc_credit_cart_review_pre_form_submit($form, &$form_state) {
  $session_card_data = base64_decode($_POST['sescrd']);

  $_SESSION['sescrd'] = $session_card_data;
  uc_credit_cache('save', $session_card_data);
}

/**
 * Clears the temporary CC data if the review order form submits.
 */
function uc_credit_cart_review_post_form_submit($form, &$form_state) {
  if (!empty($_SESSION['uc_checkout'][$_SESSION['cart_order']]['do_complete'])) {
    // Otherwise stuff it back in the session for the next pageload.
    unset($_SESSION['sescrd']);
  }
}

/**
 * Validates a CVV number during checkout.
 */
function _uc_credit_valid_cvv($cvv) {
  $digits = array();

  if (variable_get('uc_credit_visa', TRUE) ||
      variable_get('uc_credit_mastercard', TRUE) ||
      variable_get('uc_credit_discover', TRUE)) {
    $digits[] = 3;
  }
  if (variable_get('uc_credit_amex', TRUE)) {
    $digits[] = 4;
  }

  // Fail validation if it's non-numeric or an incorrect length.
  if (!is_numeric($cvv) || (count($digits) > 0 && !in_array(strlen($cvv), $digits))) {
    return FALSE;
  }

  return TRUE;
}

/**
 * Validates a credit card number during checkout.
 *
 * Luhn algorithm.  See: http://www.merriampark.com/anatomycc.htm
 */
function _uc_credit_valid_card_number($number) {
  $id = substr($number, 0, 1);
  if (($id == 3 && !variable_get('uc_credit_amex', TRUE)) ||
      ($id == 4 && !variable_get('uc_credit_visa', TRUE)) ||
      ($id == 5 && !variable_get('uc_credit_mastercard', TRUE)) ||
      ($id == 6 && !variable_get('uc_credit_discover', TRUE)) ||
      !ctype_digit($number)) {
    return FALSE;
  }

  $total = 0;
  for ($i = 0; $i < strlen($number); $i++) {
    $digit = substr($number, $i, 1);
    if ((strlen($number) - $i - 1) % 2) {
      $digit *= 2;
      if ($digit > 9) {
        $digit -= 9;
      }
    }
    $total += $digit;
  }

  if ($total % 10 != 0) {
    return FALSE;
  }

  return TRUE;
}

/**
 * Validates a start date on a card.
 *
 * @param $month
 *   The 1 or 2-digit numeric representation of the month, i.e. 1, 6, 12.
 * @param $year
 *   The 4-digit numeric representation of the year, i.e. 2008.
 *
 * @return
 *   TRUE for cards whose start date is blank (both month and year) or in the
 *   past, FALSE otherwise.
 */
function _uc_credit_valid_card_start($month, $year) {
  if (empty($month) && empty($year)) {
    return TRUE;
  }

  if (empty($month) || empty($year)) {
    return FALSE;
  }

  if ($year > date('Y')) {
    return FALSE;
  }
  elseif ($year == date('Y')) {
    if ($month > date('n')) {
      return FALSE;
    }
  }

  return TRUE;
}

/**
 * Validates an expiration date on a card.
 *
 * @param $month
 *   The 1 or 2-digit numeric representation of the month, i.e. 1, 6, 12.
 * @param $year
 *   The 4-digit numeric representation of the year, i.e. 2008.
 *
 * @return
 *   TRUE for non-expired cards, FALSE for expired.
 */
function _uc_credit_valid_card_expiration($month, $year) {
  if ($year < date('Y')) {
    return FALSE;
  }
  elseif ($year == date('Y')) {
    if ($month < date('n')) {
      return FALSE;
    }
  }

  return TRUE;
}

/**
 * Validates an issue number on a card; returns TRUE or FALSE.
 */
function _uc_credit_valid_card_issue($issue) {
  if (empty($issue) || (is_numeric($issue) && $issue > 0)) {
    return TRUE;
  }

  return FALSE;
}

/**
 * Loads the key for CC number encryption from a file.
 *
 * Path to key file is stored in system variable 'uc_credit_encryption_path'.
 * Key file name is stored in constant UC_CREDIT_KEYFILE_NAME.
 *
 * @return
 *   FALSE if no encryption key is found.
 */
function uc_credit_encryption_key() {
  static $key;

  if (!empty($key)) {
    return $key;
  }

  $key_dir = variable_get('uc_credit_encryption_path', '');
  if (is_dir($key_dir)) {
    $key_file = $key_dir . '/' . UC_CREDIT_KEYFILE_NAME;
    if (file_exists($key_file)) {
      if (!$file = @fopen($key_file, 'r')) {
        return FALSE;
      }

      $key = fread($file, filesize($key_file));
      fclose($file);
    }
  }
  else {
    return FALSE;
  }

  return $key;
}

/**
 * Saves a CC data array to an order's data array.
 */
function _uc_credit_save_cc_data_to_order($cc_data, $order_id) {
  // Save only some limited, PCI compliant data.
  $cc_data['cc_number'] = substr($cc_data['cc_number'], -4);
  unset($cc_data['cc_cvv']);

  // Load up the existing data array.
  $data = db_query("SELECT data FROM {uc_orders} WHERE order_id = :id", array(':id' => $order_id))->fetchField();
  $data = unserialize($data);

  // Stuff the serialized and encrypted CC details into the array.
  $crypt = new UbercartEncryption();
  $data['cc_data'] = $crypt->encrypt(uc_credit_encryption_key(), base64_encode(serialize($cc_data)));
  uc_store_encryption_errors($crypt, 'uc_credit');

  // Save it again.
  db_update('uc_orders')
    ->fields(array('data' => serialize($data)))
    ->condition('order_id', $order_id)
    ->execute();
}

/**
 * Returns an array of default credit card transaction types.
 */
function uc_credit_transaction_types() {
  $types = array(
    UC_CREDIT_AUTH_ONLY => t('Authorization only'),
    UC_CREDIT_PRIOR_AUTH_CAPTURE => t('Prior authorization capture'),
    UC_CREDIT_AUTH_CAPTURE => t('Authorize and capture immediately'),
    UC_CREDIT_REFERENCE_TXN => t('Reference transaction'),
  );

  return $types;
}

/**
 * Retrieves the ID of the default credit card gateway.
 *
 * @return
 *   A string containing the ID of the default gateway or FALSE if none exists
 *   or none have valid credit callbacks.
 */
function uc_credit_default_gateway() {
  // Get an array of enabled payment gateways available for the payment method.
  $gateways = _uc_payment_gateway_list('credit', TRUE);

  // Return FALSE if we found no gateways.
  if (empty($gateways)) {
    return FALSE;
  }

  // Find the default gateway, or otherwise choose the first available.
  $default = variable_get('uc_payment_credit_gateway', 'none');
  $gateway = isset($gateways[$default]) ? $gateways[$default] : reset($gateways);

  // Return FALSE if the credit callback does not exist.
  return function_exists($gateway['credit']) ? $gateway['id'] : FALSE;
}

/**
 * Stores a credit card authorization to an order's data array.
 *
 * @param $order_id
 *   The order associated with the credit card authorization.
 * @param $auth_id
 *   The payment service's ID for the authorization.
 * @param $amount
 *   The amount that was authorized on the card.
 *
 * @return
 *   The entire updated data array for the order.
 */
function uc_credit_log_authorization($order_id, $auth_id, $amount) {
  // Load the existing order data array.
  $data = db_query("SELECT data FROM {uc_orders} WHERE order_id = :id", array(':id' => $order_id))->fetchField();
  $data = unserialize($data);

  // Add the authorization to the cc_txns.
  $data['cc_txns']['authorizations'][$auth_id] = array(
    'amount' => $amount,
    'authorized' => REQUEST_TIME,
  );

  // Save the updated data array to the database.
  db_update('uc_orders')
    ->fields(array('data' => serialize($data)))
    ->condition('order_id', $order_id)
    ->execute();

  return $data;
}

/**
 * Logs the capture of a prior authorization to an order's data array.
 *
 * @param $order_id
 *   The order associated with the credit card capture.
 * @param $auth_id
 *   The payment service's ID for the authorization that was captured.
 *
 * @return
 *   The entire updated data array for the order or FALSE to indicate the
 *   specified authorization was not found.
 */
function uc_credit_log_prior_auth_capture($order_id, $auth_id) {
  // Load the existing order data array.
  $data = db_query("SELECT data FROM {uc_orders} WHERE order_id = :id", array(':id' => $order_id))->fetchField();
  $data = unserialize($data);

  // Return FALSE if we can't find the authorization.
  if (empty($data['cc_txns']['authorizations'][$auth_id])) {
    return FALSE;
  }

  // Otherwise log the capture timestamp to the authorization.
  $data['cc_txns']['authorizations'][$auth_id]['captured'] = REQUEST_TIME;

  // Save the updated data array to the database.
  db_update('uc_orders')
    ->fields(array('data' => serialize($data)))
    ->condition('order_id', $order_id)
    ->execute();

  return $data;
}

/**
 * Logs a credit card reference to an order's data array.
 *
 * @param $order_id
 *   The order associated with the credit card details.
 * @param $ref_id
 *   The payment service's ID for the reference that may be used to charge the
 *     same credit card at a later date.
 * @param $cc_number
 *   The credit card number associated with this reference.  Only the last 4
 *     digits will be stored.
 *
 * @return
 *   The entire updated data array for the order.
 */
function uc_credit_log_reference($order_id, $ref_id, $cc_number) {
  // Load the existing order data array.
  $data = db_query("SELECT data FROM {uc_orders} WHERE order_id = :id", array(':id' => $order_id))->fetchField();
  $data = unserialize($data);

  $data['cc_txns']['references'][$ref_id] = array(
    'card' => substr($cc_number, -4),
    'created' => REQUEST_TIME,
  );

  // Save the updated data array to the database.
  db_update('uc_orders')
    ->fields(array('data' => serialize($data)))
    ->condition('order_id', $order_id)
    ->execute();

  return $data;
}

/**
 * Returns the credit transaction types available for a payment gateway.
 */
function uc_credit_gateway_txn_types($gateway) {
  $types = array();

  // Get the transaction types associated with this gateway.
  $types = _uc_payment_gateway_data($gateway, 'credit_txn_types');

  // Default to authorization plus capture if none are specified.
  if (empty($types)) {
    if (!is_null(_uc_payment_gateway_data($gateway, 'credit'))) {
      $types = array(UC_CREDIT_AUTH_CAPTURE);
    }
    else {
      // Or an empty array if the gateway doesn't even handle credit payments.
      $types = array();
    }
  }

  return $types;
}

/**
 * Title callback for admin/store/orders/%uc_order/credit.
 */
function uc_credit_terminal_title($order) {
  return t('Credit card terminal: Order @order_id', array('@order_id' => $order->order_id));
}
