<?php
// $Id$

/**
 * @file
 * Ãœbercart Attribute module.
 *
 * Allows customers to buy slightly different products from the same listing.
 *
 * Many manufacturers provide options to their products. This module provides a way
 * for store administrators to consolidate these options into one product instead of
 * listing each combination separately. This is accomplished through the use of Drupal's
 * hook system.
 * Coded by: Lyle Mantooth
 */

/******************************************************************************
 * Drupal Hooks                                                               *
 ******************************************************************************/

/**
 * Implementation of hook_help().
 */
function uc_attribute_help($section){
  switch($section){
    case 'node/'. arg(1) .'/edit/attributes':
      return t('Select attributes to add to this product. Then, choose a default option for each attribute.');
    case 'node/'. arg(1) .'/edit/adjustments':
      return t("If a specific combination of attributes causes a change in a product's SKU,
        put the new SKU in the appropriate field. Hover over a row to get a reminder of the 
        meaning of an attribute combination.<br/>
        <strong>Warning:</strong> <em>If any attributes are added to or removed from this product, all work on this page will be lost!</em>");
  }
}

/**
 * Implementation of hook_menu().
 */
function uc_attribute_menu($may_cache){
  if ($may_cache){
    $items[] = array('path' => 'admin/store/products/attributes',
      'title' => t('Manage attributes'),
      'description' => t('Create and edit attributes and options.'),
      'access' => user_access('administer products'),
      'callback' => 'uc_attribute_default',
      'type' => MENU_NORMAL_ITEM,
      'weight' => -1,
    );
    $items[] = array('path' => 'admin/store/settings/attributes',
      'title' => t('Attribute settings'),
      'description' => t('Configure the attribute settings'),
      'access' => user_access('administer products'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('uc_attribute_admin_settings'),
      'type' => MENU_NORMAL_ITEM,
    );
  }
  else{
    $items[] = array('path' => 'admin/store/products/attributes/'. arg(4),
      'title' => t('Product attribute'),
      'access' => user_access('administer products'),
      'callback' => 'uc_attribute_view',
      'callback arguments' => array(arg(4)),
      'type' => MENU_CALLBACK,
    );
    $items[] = array('path' => 'admin/store/products/attributes/'. arg(4) .'/edit',
      'title' => t('Edit attribute'),
      'access' => user_access('administer products'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('uc_attribute_form', arg(4)),
      'type' => MENU_CALLBACK,
    );
    $items[] = array('path' => 'admin/store/products/attributes/'. arg(4) .'/add',
      'title' => t('Add option'),
      'access' => user_access('administer products'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('uc_attribute_option_form', arg(4), null),
      'type' => MENU_CALLBACK,
    );
    $items[] = array('path' => 'admin/store/products/attributes/'. arg(4) .'/delete',
      'access' => user_access('administer products'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('uc_attribute_delete_confirm', arg(4)),
      'type' => MENU_CALLBACK,
    );
    $items[] = array('path' => 'admin/store/products/attributes/'. arg(4) .'/'. arg(5) .'/edit',
      'title' => t('Edit option'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('uc_attribute_option_form', arg(4), arg(5)),
      'type' => MENU_CALLBACK,
    );
    $items[] = array('path' => 'admin/store/products/attributes/'. arg(4) .'/'. arg(5) .'/delete',
      'title' => t('Delete option'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('uc_attribute_option_delete_confirm', arg(4), arg(5)),
      'type' => MENU_CALLBACK,
    );

    $items[] = array('path' => 'admin/store/products/classes/'. arg(4) .'/attributes',
      'title' => t('Attributes'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('uc_object_attributes_form', arg(4), 'class'),
      'weight' => 1,
      'type' => MENU_LOCAL_TASK,
    );
    $items[] = array('path' => 'admin/store/products/classes/'. arg(4) .'/options',
      'title' => t('Attribute options'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('uc_object_options_form', arg(4), 'class'),
      'weight' => 2,
      'type' => MENU_LOCAL_TASK,
    );

    // Insert subitems into the edit node page for product types.
    if (arg(0) == 'node' && is_numeric(arg(1)) && arg(2) == 'edit'){
      $node = node_load(arg(1));
      $types = uc_product_node_info();
      if ($node->nid && in_array($node->type, array_keys($types))){
        $items[] = array('path' => 'node/'. arg(1) .'/edit/attributes',
          'title' => t('Attributes'),
          'callback' => 'drupal_get_form',
          'callback arguments' => array('uc_object_attributes_form', arg(1), 'product'),
          'weight' => 1,
          'type' => MENU_LOCAL_TASK,
        );
        $items[] = array('path' => 'node/'. arg(1) .'/edit/options',
          'title' => t('Options'),
          'callback' => 'drupal_get_form',
          'callback arguments' => array('uc_object_options_form', arg(1), 'product'),
          'weight' => 2,
          'type' => MENU_LOCAL_TASK,
        );
        $items[] = array('path' => 'node/'. arg(1) .'/edit/adjustments',
          'title' => t('Adjustments'),
          'callback' => 'drupal_get_form',
          'callback arguments' => array('uc_product_adjustments_form', arg(1)),
          'weight' => 3,
          'type' => MENU_LOCAL_TASK,
        );
      }
    }
    drupal_add_css(drupal_get_path('module', 'uc_attribute') .'/uc_attribute.css');
  }
  return $items;
}

/**
 * Implementation of hook_form_alter().
 *
 * Attach option selectors to the form with the "Add to Cart" button.
 */
function uc_attribute_form_alter($form_id, &$form){
  if (strpos($form_id, 'add_to_cart_form') || strpos($form_id, 'add_product_form')){
    // If the node has a product list, add attributes to them
    if (count(element_children($form['products']))){
      foreach (element_children($form['products']) as $key){
        $form['products'][$key] = _uc_attribute_alter_form($form['products'][$key]);
        if (isset($form['products'][$key]['attributes'])){
          $form['products'][$key]['#type'] = 'fieldset';
        }
      }
    }
    // If not, add attributes to the node.
    else{
      $form['attributes'] = array('#tree' => true, '#weight' => -1);
      $form = _uc_attribute_alter_form($form);
    }
  }
}

/**
 * Implementation of hook_nodeapi().
 */
function uc_attribute_nodeapi(&$node, $op, $arg3 = null, $arg4 = null){
  if (in_array($node->type, array_keys(uc_product_node_info()))){
    switch($op){
      case 'insert':
        db_query("INSERT IGNORE INTO {uc_product_attributes} (nid, aid, ordering, required, default_option) SELECT %d, aid, ordering, required, default_option FROM {uc_class_attributes} WHERE pcid = '%s'", $node->nid, $node->type);
        db_query("INSERT IGNORE INTO {uc_product_options} (nid, oid, cost, price, weight, ordering) SELECT %d, oid, cost, price, weight, ordering FROM {uc_class_attribute_options} WHERE pcid = '%s'", $node->nid, $node->type);
      break;
      case 'delete':
        db_query("DELETE FROM {uc_product_options} WHERE nid = %d", $node->nid);
        db_query("DELETE FROM {uc_product_adjustments} WHERE nid = %d", $node->nid);
        db_query("DELETE FROM {uc_product_attributes} WHERE nid = %d", $node->nid);
      break;
      case 'update index':
        $output = '';
        $attributes = uc_product_get_attributes($node->nid);
        foreach ($attributes as $attribute){
          $output .= '<h3>'. $attribute->name .'</h3>';
          foreach ($attribute->options as $option){
            $output .= $option->name .' ';
          }
          $output .= "\n";
        }
        $result = db_query("SELECT model FROM {uc_product_adjustments} WHERE nid = %d", $node->nid);
        while ($adjustment = db_fetch_object($result)){
          $output .= '<h2>'. $adjustment->model ."<h2>\n";
        }
      return $output;
    }
  }
}

/******************************************************************************
 * Ubercart Hooks                                                             *
 ******************************************************************************/

/**
 * Stores the customer's choices in the cart.
 */
function uc_attribute_add_to_cart_data($form_values){
  $combination = array();
  if (!isset($form_values['attributes'])){
    return array('attributes' => array(), 'model' => null);
  }
  foreach ($form_values['attributes'] as $aid => $value){
    if (is_numeric($value)){
      $combination[$aid] = $value;
    }
  }
  $result = db_query("SELECT model FROM {uc_product_adjustments} WHERE nid = %d AND combination LIKE '%s'", $form_values['nid'], serialize($combination));
  $model = db_result($result);
  // drupal_set_message('Attributes to add to order Array(aid => oid):<pre>'. print_r($form_values['attributes'], true) . $model .'</pre>');
  // Preserve the 'attributes' key to allow other modules to add to the data field.
  return array('attributes' => $form_values['attributes'], 'model' => $model);
}

/**
 * Implementation of hook_product_class().
 */
function uc_attribute_product_class($type, $op){
  switch ($op){
    case 'delete':
      db_query("DELETE FROM {uc_class_attributes} WHERE pcid = '%s'", $type);
      db_query("DELETE FROM {uc_class_attribute_options} WHERE pcid = '%s'", $type);
    break;
  }
}

/**
 * Implementation of hook_cart_item().
 */
function uc_attribute_cart_item($op, &$item) {
  switch ($op) {
    case 'load':
      $item->options = _uc_cart_product_get_options($item);
      $op_costs = 0;
      $op_prices = 0;
      $op_weight = 0;
      foreach ($item->options as $option){
        $op_costs += $option['cost'];
        $op_prices += $option['price'];
        $op_weight += $option['weight'];
      }
      $item->cost += $op_costs;
      $item->price += $op_prices;
      $item->weight += $op_weight;
      if (!empty($item->data['model'])) {
        $item->model = $item->data['model'];
      }
      break;
  }
}

/******************************************************************************
 * Menu Callbacks                                                             *
 ******************************************************************************/

/**
 * Change the display of attribute option prices.
 *
 * @ingroup forms
 */
function uc_attribute_admin_settings(){
  $form = array();
  
  $form['uc_attribute_option_price_format'] = array('#type' => 'radios',
    '#title' => t('Option price format'),
    '#default_value' => variable_get('uc_attribute_option_price_format', 'adjustment'),
    '#options' => array('none' => t('Do not display'),
      'adjustment' => t('Display price adjustment'),
      'total' => t('Display total price'),
    ),
    '#description' => t('Formats the price is in the attribute selection form when the customer adds a product to their cart. The total price will only be displayed on products with only one attribute.'),
  );
  
  return system_settings_form($form);
}

/**
 * Display a list of attributes and a form to add more.
 *
 * @see uc_attribute_form
 */
function uc_attribute_default(){
  $result = db_query("SELECT a.aid, a.name, a.ordering, COUNT(ao.oid) AS options FROM {uc_attributes} AS a LEFT JOIN {uc_attribute_options} AS ao ON a.aid = ao.aid GROUP BY a.aid ORDER BY a.ordering, a.name");
  $header = array(t('Name'), t('# of Options'), t('Order'), array('data' => t('Operations'), 'colspan' => '3'));
  $rows = array();
  while($attr = db_fetch_object($result)){
    $rows[] = array($attr->name, $attr->options, $attr->ordering, l(t('options'), 'admin/store/products/attributes/'. $attr->aid .'/options'), l(t('edit'), 'admin/store/products/attributes/'. $attr->aid .'/edit'), l(t('delete'), 'admin/store/products/attributes/'. $attr->aid .'/delete'));
  }
  if (count($rows) == 0){
    $rows[] = array(array('data' => t('No product attributes have been defined yet.'), 'colspan' => '6'));
  }
  
  $output = theme('table', $header, $rows);
  $output .= '<h2>'. t('Add an Attribute') .'</h2>';
  $output .= drupal_get_form('uc_attribute_form');
  
  return $output;
}

/**
 * Display options and the modifications to products they represent.
 *
 * @see uc_attribute_option_form
 */
function uc_attribute_view($attr_id){
  if (!($attribute = uc_attribute_load($attr_id))){
    drupal_set_message(t('Attribute with aid @id does not exist.', array('@id' => $attr_id)), 'error');
    drupal_goto('admin/store/products/attributes');
  }
  $breadcrumbs = drupal_get_breadcrumb();
  $breadcrumbs[] = l(t('Attributes'), 'admin/store/products/attributes/');
  drupal_set_breadcrumb($breadcrumbs);
  $output = '<h2>'. $attribute->name .'</h2>';
  $rows = array();
  foreach ($attribute->options as $key => $input){
    $rows[] = array($input->name, $input->cost, $input->price, $input->weight, $input->ordering, l(t('edit'), 'admin/store/products/attributes/'. $attr_id .'/'. $key .'/edit'), l(t('delete'), 'admin/store/products/attributes/'. $attr_id .'/'. $key .'/delete'));
  }
  if (count($rows) == 0){
    $rows[] = array(array('data' => t('No options defined for this product attribute.'), 'colspan' => '7'));
  }
  $header = array(t('Name'), t('Default cost'), t('Default price'), t('Default weight'), t('Order'), array('data' => t('Operations'), 'colspan' => '2'));
  $output .= theme('table', $header, $rows);
  $output .= '<h2>'. t('Add an option') .'</h2>';
  $output .= drupal_get_form('uc_attribute_option_form', $attr_id);
  //$output .= l(t('Add a field'), 'admin/store/products/attributes/'. $attr_id .'/add');
  return $output;
}

/**
 * Form builder for product attributes.
 *
 * @ingroup forms
 * @see uc_attribute_form_validate
 * @see uc_attribute_form_submit
 */
function uc_attribute_form($attr_id = null){
  $attribute = uc_attribute_load($attr_id);
  if ($attr_id){
    $form['aid'] = array('#type' => 'hidden', '#value' => $attr_id);
    $crumbs = drupal_get_breadcrumb();
    $crumbs[] = l(t('Attributes'), 'admin/store/products/attributes');
    drupal_set_breadcrumb($crumbs);
  }
  $form['name'] = array('#type' => 'textfield',
    '#title' => t('Attribute name'),
    '#default_value' => $attribute->name,
    '#weight' => 0,
  );
  $form['ordering'] = array('#type' => 'weight',
    '#title' => t('Order'),
    '#default_value' => $attribute->ordering,
    '#weight' => 1,
  );
  $form['op'] = array('#type' => 'submit',
    '#value' => t('Submit'),
    '#weight' => 2,
  );
  
  return $form;
}

/**
 * Validate function for uc_attribute_add_form().
 */
function uc_attribute_form_validate($form_id, $form_values){
  if (empty($form_values['name'])){
    form_set_error(t('Product attributes must have names.'));
  }
}

/**
 * Submit function for uc_attribute_add_form().
 */
function uc_attribute_form_submit($form_id, $form_values){
  if (isset($form_values['aid'])){
    db_query("UPDATE {uc_attributes} SET name = '%s', ordering = %d WHERE aid = %d", $form_values['name'], $form_values['ordering'], $form_values['aid']);
  }
  else{
    db_query("INSERT INTO {uc_attributes} (name, ordering) VALUES ('%s', %d)", $form_values['name'], $form_values['ordering']);
  }
  return 'admin/store/products/attributes';
}

/**
 * Confirms the deletion of the given attribute.
 */
function uc_attribute_delete_confirm($aid){
  $result = db_query("SELECT COUNT(*) AS number FROM {uc_product_attributes} WHERE aid = %d", $aid);
  $products = db_fetch_object($result);
  $form['aid'] = array('#type' => 'value', '#value' => $aid);
  $form['#redirect'] = 'admin/store/products/attributes';
  $output = confirm_form($form, t('Be very sure you want to delete this product attribute. '), 'admin/store/products/attributes',
    format_plural($products->number, 'There is 1 product with this attribute. ', 'There are @count products with this attribute. '),
    t('Continue'), t('Cancel'));
  
  return $output;
}

/**
 * Submit function for uc_attribute_delete_confirm().
 */
function uc_attribute_delete_confirm_submit($form_id, $form_values){
  if ($form_values['confirm']){
    db_query("DELETE FROM co USING {uc_class_attribute_options} AS co, {uc_attribute_options} AS ao WHERE co.oid = ao.oid AND ao.aid = %d", $form_values['aid']);
    db_query("DELETE FROM {uc_class_attributes} WHERE aid = %d", $form_values['aid']);
    db_query("DELETE FROM po USING {uc_product_options} AS po, {uc_attribute_options} AS ao WHERE po.oid = ao.oid AND ao.aid = %d", $form_values['aid']);
    db_query("DELETE FROM pd USING {uc_product_adjustments} AS pd, {uc_product_attributes} AS pa WHERE pd.nid = pa.nid AND pa.aid = %d", $form_values['aid']);
    db_query("DELETE FROM {uc_product_attributes} WHERE aid = %d", $form_values['aid']);
    db_query("DELETE FROM {uc_attribute_options} WHERE aid = %d", $form_values['aid']);
    db_query("DELETE FROM {uc_attributes} WHERE aid = %d", $form_values['aid']);
    drupal_set_message(t('Product attribute deleted.'));  
  }
}

/**
 * Form builder for attribute options.
 *
 * @ingroup forms
 * @see uc_attribute_option_form_validate
 * @see uc_attribute_option_form_submit
 */
function uc_attribute_option_form($attr_id, $opt_id = null){
  $attribute = uc_attribute_load($attr_id);
  
  if ($opt_id){
    $crumbs = drupal_get_breadcrumb();
    $crumbs[] = l(t('Attributes'), 'admin/store/products/attributes');
    $crumbs[] = l($attribute->name, 'admin/store/products/attributes/'. $attr_id);
    drupal_set_breadcrumb($crumbs);
    $option = $attribute->options[$opt_id];
  }
  else{
    $option = new stdClass();
  }
  $form['name'] = array('#type' => 'textfield',
    '#title' => t('Option name'),
    '#default_value' => $option->name,
    '#required' => true,
    '#weight' => 0,
  );
  $form['cost'] = array('#type' => 'textfield',
    '#title' => t('Default cost'),
    '#default_value' => $option->cost,
    '#description' => t('Adjusts the product cost by the specified dollar amount.'),
    '#weight' => 1,
  );
  $form['price'] = array('#type' => 'textfield',
    '#title' => t('Default price'),
    '#default_value' => $option->price,
    '#description' => t('Adjusts the product price by the specified dollar amount.'),
    '#weight' => 2,
  );
  $form['weight'] = array('#type' => 'textfield',
    '#title' => t('Default weight'),
    '#default_value' => $option->weight,
    '#description' => t('Adjusts the product weight by this value in pounds.'),
    '#weight' => 3,
  );
  $form['ordering'] = array('#type' => 'weight',
    '#title' => t('Order'),
    '#default_value' => $option->ordering,
    '#weight' => 4,
  );
  $form['aid'] = array('#type' => 'hidden', '#value' => $attr_id);
  if ($opt_id){
    $form['oid'] = array('#type' => 'hidden', '#value' => $opt_id);
  }
  $form['submit'] = array('#type' => 'submit', '#value' => t('Submit'),
    '#weight' => 10,
  );
  return $form;
}

/**
 * Validate number formats.
 */
function uc_attribute_option_form_validate($form_id, $form_values){
  $pattern = '/^-?\d*(\.\d*)?$/';
  $price_error = t('This must be in a valid number format. No commas and only one decimal point.');
  if(!is_numeric($form_values['cost']['#value']) && !preg_match($pattern, $form_values['cost']['#value'])){
    form_set_error('cost', $price_error);
  }
  if(!is_numeric($form_values['price']['#value']) && !preg_match($pattern, $form_values['price']['#value'])){
    form_set_error('price', $price_error);
  }
  if(!is_numeric($form_values['weight']['#value']) && !preg_match($pattern, $form_values['weight']['#value'])){
    form_set_error('weight', $price_error);
  }
}

/**

 * Submit function for uc_attribute_option_form().
 */
function uc_attribute_option_form_submit($form_id, $form_values){
  if (!isset($form_values['oid'])){
    db_query("INSERT INTO {uc_attribute_options} (aid, name, cost, price, weight, ordering) VALUES (%d, '%s', %f, %f, %f, %d)",
      $form_values['aid'], $form_values['name'], $form_values['cost'], $form_values['price'], $form_values['weight'], $form_values['ordering']);
  }
  else{
    db_query("UPDATE {uc_attribute_options} SET name = '%s', cost = %f, price = %f, weight = %f, ordering = %d WHERE aid = %d AND oid = %d",
      $form_values['name'], $form_values['cost'], $form_values['price'], $form_values['weight'], $form_values['ordering'], $form_values['aid'], $form_values['oid']);
  }
  return 'admin/store/products/attributes/'. $form_values['aid'];
}

/**
 * Confirms deletion of the given attribute option.
 */
function uc_attribute_option_delete_confirm($attr_id, $opt_id){
  $form['aid'] = array('#type' => 'value', '#value' => $attr_id);
  $form['oid'] = array('#type' => 'value', '#value' => $opt_id);
  //$form['#redirect'] = 'admin/store/products/attributes/'. $attr_id .'/edit';
  $output = confirm_form($form, t('Are you sure you want to delete this option?'), 'admin/store/products/attributes/'. $attr_id .'/edit',
    '', t('Continue'), t('Cancel'));
  return $output;
}

/**
 * Submit function for uc_attribute_option_delete_confirm().
 */
function uc_attribute_option_delete_confirm_submit($form_id, $form_values){
  if ($form_values['confirm']){
    $match = 'i:'. $form_values['aid'] .';s:'. strlen($form_values['oid']) .':"'. $form_values['oid'] .'";';
    db_query("DELETE FROM {uc_product_adjustments} WHERE combination LIKE '%%%s%%'", $match);
    db_query("DELETE ao, co, po FROM {uc_attribute_options} AS ao LEFT JOIN {uc_product_options} AS po ON ao.oid = po.oid LEFT JOIN {uc_class_attribute_options} AS co ON ao.oid = co.oid WHERE ao.oid = %d", $form_values['oid']);
  }
  return 'admin/store/products/attributes/'. $form_values['aid'] .'/options';
}

/**
 * Form builder to associate attributes with products or classes.
 *
 * @param $id The nid of the product, or the pcid of a class.
 * @param $type Either 'product' or 'class'
 * @ingroup forms
 * @see theme_uc_object_attributes_form
 * @see uc_object_attributes_form_submit
 */
function uc_object_attributes_form($id, $type){
  $location = array();
  $location[] = menu_get_item(null, 'admin');
  $location[] = menu_get_item(null, 'admin/store');
  $location[] = menu_get_item(null, 'admin/store/products');
  $location[] = menu_get_item(null, 'admin/store/products/attributes');
  $breadcrumb = drupal_get_breadcrumb();
  if (count($breadcrumb) == 1){
    foreach ($location as $item){
      $breadcrumb[] = l($item['title'], $item['path']);
    }
    drupal_set_breadcrumb($breadcrumb);
  }
  
  $form['admin_link'] = array('#value' => l(t('Attributes administration'), 'admin/store/products/attributes'));
  if ($type == 'product'){
    $product = node_load($id);
    drupal_set_title(check_plain($product->title));
    // Get list of attributes already associated with the node.
    $chosen_attr = uc_product_get_attributes($id);
  }
  else if ($type == 'class'){
    $class = uc_product_class_load($id);
    drupal_set_title(check_plain($class->name));
    // Get list of attributes already associated with the class.
    $chosen_attr = uc_class_get_attributes($id);
  }
  $form['chosen_attr'] = array();
  if (count($chosen_attr)){
    foreach ($chosen_attr as $prod_attr){
      $opt = $prod_attr->options[$prod_attr->default_option];
      /* if (!$opt){
        $opt = reset($prod_attr->options); // non-destructive shift
      } */
      $form['chosen_attr'][$prod_attr->aid] = array(
        'remove' => array('#type' => 'checkbox', '#default_value' => 0),
        'name' => array('#type' => 'markup', '#value' => $prod_attr->name),
        'option' => array('#type' => 'markup', '#value' => $opt ? ($opt->name .' ('. uc_currency_format($opt->price) .')' ) : t('n/a')),
        'required' => array('#type' => 'checkbox', '#default_value' => $prod_attr->required),
        'ordering' => array('#type' => 'weight', '#default_value' => $prod_attr->ordering),
      );
    }
  }
  //$form['table'] = array('#type' => 'markup', '#value' => theme('table', $header, $rows), '#weight' => -5);
  
  $chosen_aids = array();
  foreach($chosen_attr as $attr){
    $chosen_aids[] = $attr->aid;
  }

  // Get list of attributes NOT associated with this node.
  $result = db_query("SELECT a.aid, a.name FROM {uc_attributes} AS a LEFT JOIN {uc_attribute_options} AS ao ON a.aid = ao.aid GROUP BY aid ORDER BY a.name");
  $other_attr = array();
  while ($attr = db_fetch_object($result)){
    if (!in_array($attr->aid, $chosen_aids)){
      $other_attr[$attr->aid] = $attr->name;
    }
  }
  //print '<pre>'. print_r($chosen_attr, true) .'</pre>';
  
  $form['#tree'] = true;
  
  $form['attributes'] = array('#type' => 'select',
    '#multiple' => true,
    '#title' => t('Attributes'),
    //'#default_value' => $form_values['attributes'],
    '#options' => (count($other_attr) ? $other_attr : array(t('No attributes left to add.'))),
    '#weight' => -1
  );
  $form['add'] = array('#type' => 'submit', '#value' => t('Continue'), '#weight' => 0);
  if (!count($other_attr)){
    $form['attributes']['#disabled'] = 'disabled';
  }
  $form['id'] = array('#type' => 'value', '#value' => $id);
  $form['type'] = array('#type' => 'value', '#value' => $type);
  //drupal_set_message('<pre>'. htmlspecialchars(print_r($form, true)) .'</pre>');
  return $form;
}

/**
 * Display the formatted attribute form.
 *
 * @ingroup themeable
 */
function theme_uc_object_attributes_form($form){
  $output = drupal_render($form['admin_link']);
  $header = array(t('Remove'), t('Name'), t('Default option'), t('Required'), t('Order'));
  if (count(element_children($form['chosen_attr']))){
    foreach (element_children($form['chosen_attr']) as $attr){
      $rows[] = array(drupal_render($form['chosen_attr'][$attr]['remove']), drupal_render($form['chosen_attr'][$attr]['name']), drupal_render($form['chosen_attr'][$attr]['option']), drupal_render($form['chosen_attr'][$attr]['required']),  drupal_render($form['chosen_attr'][$attr]['ordering']));
    }
  }
  else{
    $rows[] = array(array('data' => t('No attributes have been selected. Add some below.'), 'colspan' => 4));
  }
  $output .= theme('table', $header, $rows);
  
  $output .= drupal_render($form);
  return $output;
}

/**
 * Submit function for uc_product_attributes_form().
 */
function uc_object_attributes_form_submit($form_id, $form_values){
  // adjustments also have no meaning if attributes are changed in any way.
  if ($form_values['type'] == 'product'){
    db_query("DELETE FROM {uc_product_adjustments} WHERE nid = %d", $form_values['id']);
    $attr_table = '{uc_product_attributes}';
    $opt_table = '{uc_product_options}';
    $id = 'nid';
    $type = '%d';
  }
  else if ($form_values['type'] == 'class'){
    $attr_table = '{uc_class_attributes}';
    $opt_table = '{uc_class_attribute_options}';
    $id = 'pcid';
    $type = "'%s'";
  }
  $values = array($form_values['id']);
  if (is_array($form_values['chosen_attr'])){
    foreach($form_values['chosen_attr'] as $aid => $attr){
      if ($attr['remove']){
        $replace .= ', %d';
        $values[] = $aid;
      }
      else{
        db_query("UPDATE $attr_table SET ordering = %d, required = %d WHERE aid = %d AND $id = $type", $attr['ordering'], $attr['required'], $aid, $form_values['id']);
      }
    }
  }
  $replace = '('. substr($replace, 2) .')';
  if (count($values) > 1){
    db_query("DELETE po FROM $opt_table AS po LEFT JOIN {uc_attribute_options} AS ao ON po.oid = ao.oid WHERE po.$id = %d AND ao.aid IN ". $replace, $values);
    db_query("DELETE FROM $attr_table WHERE $id = $type AND aid IN ". $replace, $values);
  }
  foreach($form_values['attributes'] as $aid){
    db_query("INSERT INTO $attr_table ($id, aid, ordering, default_option) SELECT $type, aid, ordering, %d FROM {uc_attributes} WHERE aid = %d",
      $form_values['id'], 0, $aid);
  }
  //return 'node/'. $form_values['id'] .'/edit/attributes';
}

/**
 * Form builder to attach attribute options to products or classes.
 *
 * @param $id The nid of the product, or the pcid of a class.
 * @param $type Either 'product' or 'class'
 * @ingroup forms
 * @see theme_uc_object_options_form
 * @see uc_object_options_form_submit
 */
function uc_object_options_form($obj_id, $type){
  $location = array();
  $location[] = menu_get_item(null, 'admin');
  $location[] = menu_get_item(null, 'admin/store');
  $location[] = menu_get_item(null, 'admin/store/products');
  $location[] = menu_get_item(null, 'admin/store/products/attributes');
  $breadcrumb = drupal_get_breadcrumb();
  if (count($breadcrumb) == 1){
    foreach ($location as $item){
      $breadcrumb[] = l($item['title'], $item['path']);
    }
    drupal_set_breadcrumb($breadcrumb);
  }
  $form['admin_link'] = array('#value' => l(t('Attributes administration'), 'admin/store/products/attributes'));
  if ($type == 'product'){
    $product = node_load($obj_id);
    drupal_set_title(check_plain($product->title));
    $chosen_attr = uc_product_get_attributes($obj_id);
    $table = '{uc_product_options}';
    $id = 'nid';
    $type = '%d';
		$formtype = 'product';
  }
  else if ($type == 'class'){
    $class = uc_product_class_load($obj_id);
    drupal_set_title(check_plain($class->name));
    $chosen_attr = uc_class_get_attributes($obj_id);
    $table = '{uc_class_attribute_options}';
    $id = 'pcid';
    $type = "'%s'";
		$formtype = 'class';
  }
  $form['prod_attr'] = array('#tree' => true);
  foreach ($chosen_attr as $key => $attribute){
    $form['prod_attr'][$key] = array('#prefix' => '<tr>', '#suffix' => '</tr>');
    $form['prod_attr'][$key]['name'] = array('#type' => 'markup',
      '#value' => $attribute->name,
    );
    $form['prod_attr'][$key]['aid'] = array('#type' => 'hidden',
      '#value' => $attribute->aid,
    );
    $form['prod_attr'][$key]['ordering'] = array('#type' => 'value',
      '#value' => $attribute->ordering,
    );
    
    // Display options selector.
    $form['prod_attr'][$key]['options'] = array('#weight' => 2,
    );
    $base_attr = uc_attribute_load($attribute->aid);
    if ($base_attr->options){
      $result = db_query("SELECT ao.aid, ao.oid, ao.name, ao.cost AS default_cost, ao.price AS default_price, ao.weight AS default_weight, ao.ordering AS default_ordering, po.cost, po.price, po.weight, po.ordering FROM {uc_attribute_options} AS ao LEFT JOIN $table AS po ON ao.oid = po.oid AND po.$id = $type WHERE aid = %d ORDER BY po.ordering, default_ordering, ao.name", $obj_id, $attribute->aid);
      $options = array();
      $n = db_num_rows($result);
      $i = 0;
      while ($op_array = db_fetch_object($result)){
        $oid = $op_array->oid;
        $form['prod_attr'][$key]['options'][$oid] = array();
        $options[$oid] = $op_array->name;
        $form['prod_attr'][$key]['options'][$oid]['select'] = array('#type' => 'checkbox',
          '#default_value' => (isset($attribute->options[$oid]) ? 1 : 0),
          '#title' => $op_array->name,
        );
        /* $form['prod_attr'][$key]['options'][$oid]['name'] = array('#type' => 'markup',
          '#value' => $op_array->name,
        ); */
        $form['prod_attr'][$key]['options'][$oid]['cost'] = array('#type' => 'textfield',
          '#title' => t('Cost'),
          '#default_value' => (is_null($op_array->cost) ? $op_array->default_cost : $op_array->cost),
          '#size' => 6,
        );
        $form['prod_attr'][$key]['options'][$oid]['price'] = array('#type' => 'textfield',
          '#title' => t('Price'),
          '#default_value' => (is_null($op_array->price) ? $op_array->default_price : $op_array->price),
          '#size' => 6,
        );
        $form['prod_attr'][$key]['options'][$oid]['weight'] = array('#type' => 'textfield',
          '#title' => t('Weight'),
          '#default_value' => (is_null($op_array->weight) ? $op_array->default_weight : $op_array->weight),
          '#size' => 5,
        );
        $form['prod_attr'][$key]['options'][$oid]['ordering'] = array('#type' => 'weight',
          '#title' => t('Order'),
          '#default_value' => (is_null($op_array->ordering) ? $op_array->default_ordering : $op_array->ordering),
        );
        $i++;
      }
      $form['prod_attr'][$key]['default'] = array('#type' => 'radios',
        '#options' => $options,
        '#default_value' => $attribute->default_option,
      );
    }
    else{
      $form['prod_attr'][$key]['default'] = array('#type' => 'markup',
        '#value' => t('(To be determined by customer.)'),
      );
    }
  }
  $form['submit'] = array('#type' => 'submit', '#value' => t('Submit'), '#weight' => 10);
  $form['id'] = array('#type' => 'value', '#value' => $obj_id);
  $form['type'] = array('#type' => 'value', '#value' => $formtype);
  
  return $form;
}

/**
 * Display the option form.
 *
 * @ingroup themeable
 */
function theme_uc_object_options_form($form){
  $output = drupal_render($form['admin_link']);
  $header = array(t('Attribute'), t('Default option'), array('colspan' => 5, 'data' => t('Options')));
  $rows = array();
  foreach (element_children($form['prod_attr']) as $key){
    $row = array();
    $row[] = array('data' => drupal_render($form['prod_attr'][$key]['aid']) . drupal_render($form['prod_attr'][$key]['name']), 'class' => 'attribute');
    //$row[] = array('data' => drupal_render($form['prod_attr'][$key]['default']), 'class' => 'attribute');
    $i = 0;
    if (element_children($form['prod_attr'][$key]['default'])){
      foreach (element_children($form['prod_attr'][$key]['default']) as $oid){
        $row[] = drupal_render($form['prod_attr'][$key]['default'][$oid]);
        $row[] = drupal_render($form['prod_attr'][$key]['options'][$oid]['select']);
        //$row[] = drupal_render($form['prod_attr'][$key]['options'][$oid]['name']);
        $row[] = drupal_render($form['prod_attr'][$key]['options'][$oid]['cost']);
        $row[] = drupal_render($form['prod_attr'][$key]['options'][$oid]['price']);
        $row[] = drupal_render($form['prod_attr'][$key]['options'][$oid]['weight']);
        $row[] = drupal_render($form['prod_attr'][$key]['options'][$oid]['ordering']);
        // if not the first row for the attribute, make empty cells on the left
        if ($i != 0){ 
          $row = array_pad($row, -7, '');
        }
        $i++;
        $rows[] = $row;
        $row = array();
      }
      unset($form['prod_attr'][$key]['default']);
    }
    else{
      $row[] = array('data' => drupal_render($form['prod_attr'][$key]['default']), 'colspan' => 7);
      $rows[] = $row;
    }
    $rows[] = array(array('data' => '<hr />', 'colspan' => 7));
  }
  $output .= theme('table', $header, $rows, array('class' => 'product_attributes'));
  $output .= drupal_render($form);
  return $output;
}

/**
 * Validate function for uc_product_options_form().
 */
function uc_object_options_form_validate($form_id, $form_values){
  if (isset($form_values['prod_attr'])){
    foreach ($form_values['prod_attr'] as $attribute){
      $selected_opts = array();
      if (is_array($attribute['options'])){
        foreach ($attribute['options'] as $oid => $option){
          if ($option['select'] == 1){
            $selected_opts[] = $oid;
          }
        }
      }
      if (!empty($selected_opts) && !in_array($attribute['default'], $selected_opts)){
        form_set_error($attribute['default'], t('Default value must be a valid value.'));
      }
    }
  }
}

/**
 * Submit handler for uc_object_options_form().
 */
function uc_object_options_form_submit($form_id, $form_values){
  if ($form_values['type'] == 'product'){
    $attr_table = '{uc_product_attributes}';
    $opt_table = '{uc_product_options}';
    $id = 'nid';
    $type = '%d';
  }
  else if ($form_values['type'] == 'class'){
    $attr_table = '{uc_class_attributes}';
    $opt_table = '{uc_class_attribute_options}';
    $id = 'pcid';
    $type = "'%s'";
  }
  // Adjustments have no meaning if possible option combinations are changed in any way.
  foreach ($form_values['prod_attr'] as $prod_attr){
    db_query("DELETE FROM $attr_table WHERE $id = $type AND aid = %d", $form_values['id'], $prod_attr['aid']);
    db_query("INSERT INTO $attr_table ($id, aid, ordering, required, default_option) VALUES ($type, %d, %d, %d, %d)",
      $form_values['id'], $prod_attr['aid'], $prod_attr['ordering'], $prod_attr['required'], $prod_attr['default']);
    if (is_array($prod_attr['options'])){
      foreach ($prod_attr['options'] as $oid => $option){
        db_query("DELETE FROM $opt_table WHERE $id = $type AND oid = %d", $form_values['id'], $oid);
        if ($option['select']){
          db_query("INSERT INTO $opt_table ($id, oid, cost, price, weight, ordering) VALUES ($type, %d, %f, %f, %f, %d)",
            $form_values['id'], $oid, $option['cost'], $option['price'], $option['weight'], $option['ordering']);
        }
        else if ($form_values['type'] == 'product'){
          $aid = $prod_attr['aid'];
          $match = 'i:'. $aid .';s:'. strlen($oid) .':"'. $oid .'";';
          db_query("DELETE FROM {uc_product_adjustments} WHERE nid = %d AND combination LIKE '%%%s%%'", $form_values['id'], $match);
        }
      }
    }
  }
  drupal_set_message(t('The @type options have been saved.', array('@type' => $form_values['type'])));
}

/**
 * Form builder to associate option combinations with mutations of a product's model number.
 *
 * @ingroup forms
 * @see uc_product_adjustments_form_submit
 */
function uc_product_adjustments_form($nid){
  $location = array();
  $location[] = menu_get_item(null, 'admin');
  $location[] = menu_get_item(null, 'admin/store');
  $location[] = menu_get_item(null, 'admin/store/products');
  $location[] = menu_get_item(null, 'admin/store/products/attributes');
  $breadcrumb = drupal_get_breadcrumb();
  if (count($breadcrumb)){
    foreach ($location as $item){
      $breadcrumb[] = l($item['title'], $item['path']);
    }
    drupal_set_breadcrumb($breadcrumb);
  }
  $form['admin_link'] = array('#value' => l(t('Attributes administration'), 'admin/store/products/attributes'));
  $node = node_load($nid);
  drupal_set_title(check_plain($node->title));
  //$model = db_result(db_query("SELECT model FROM {uc_products} WHERE nid = %d", $nid));
  $model = $node->model;
  //Populate table and such.
  $query_select = "SELECT DISTINCT";
  $query_from = " FROM";
  $query_where = " WHERE";
  $query_order = " ORDER BY";
  $result = db_query("SELECT * FROM {uc_product_attributes} AS pa LEFT JOIN {uc_attributes} AS a ON pa.aid = a.aid WHERE nid = %d", $nid);
  $num_prod_attr = db_num_rows($result);
  $i = 1;
  $attribute_names = '';
  $full_attributes = array();
  $values = array();
  while ($prod_attr = db_fetch_object($result)){
    $query_select .= " ao$i.aid AS aid$i, ao$i.name AS name$i, ao$i.oid AS oid$i,";
    $query_from .= " ({uc_product_options} AS po$i LEFT JOIN {uc_attribute_options} AS ao$i ON po$i.oid = ao$i.oid AND po$i.nid = %d),";
    $values[] = $nid;
    $query_where .= " ao$i.aid = ". $prod_attr->aid ." AND";
    $query_order .= " po$i.ordering, ao$i.name,";
    ++$i;
    $attribute_names .= '<th>'. $prod_attr->name .'</th>';
    $attribute_ids[] = $prod_attr->aid;
  }
  // Remove last connecting parts (commas, "AND")
  $query_select = rtrim($query_select, ',');
  $query_from = rtrim($query_from, ',');
  $query_where = substr($query_where, 0, strlen($query_where) - 4);
  $query_order = rtrim($query_order, ',');
  // $query_where .= " po1.nid = %d";
  if ($num_prod_attr){
    //Get previous values
    $result = db_query("SELECT * FROM {uc_product_adjustments} WHERE nid = %d", $nid);
    $old_vals = array();
    while ($obj = db_fetch_object($result)){
      $old_vals[] = $obj;
    }

    $result = pager_query($query_select . $query_from . $query_where . $query_order, 20, 0, null, $values);

    
    $form['original'] = array('#value' => $model,
      '#prefix' => '<br /><h2>',
      '#suffix' => '</h2>',
    );
    $form['default'] = array('#type' => 'value', '#value' => $model);
    //$form['attributes'] = array('#value' => theme('uc_attribute', 'attributes', $attribute_ids, $nid));
    //$form['query'] = array('#value' => '<pre>'. print_r($old_vals, true) .'</pre>');
    $form['table'] = array('#prefix' => '<table class="combinations">', '#suffix' => '</table>');
    $form['table']['head'] = array('#prefix' => '<thead><tr>',
      '#suffix' => '</tr></thead>',
      '#value' => $attribute_names .'<th>Model</th>',
      '#weight' => 0,
    );
    $form['table']['body'] = array('#prefix' => '<tbody>', '#suffix' => '</tbody>',
      '#weight' => 1,
      '#tree' => true,
    );
    $i = 0;
    while ($combo = db_fetch_object($result)){
      $cells = '';
      $row_title = '';
      $comb_array = array();
      for ($j = 1; $j <= $num_prod_attr; ++$j){
        $cells .= '<td>'. $combo->{'name'.$j} .'</td>';
        $row_title .= $combo->{'name'.$j} .', ';
        $comb_array[$combo->{'aid'.$j}] = $combo->{'oid'.$j};
      }
      $row_title = substr($row_title, 0, strlen($row_title) - 2);
      $serial_array = serialize($comb_array);
      $default_model = $model;
      foreach ($old_vals as $ov){
        if (!count(array_diff_assoc(unserialize($ov->combination), unserialize($serial_array)))){
          $default_model = $ov->model;
          break;
        }
      }
      $form['table']['body'][$i] = array('#prefix' => '<tr title="'. $row_title .'">', '#suffix' => '</tr>');
      $form['table']['body'][$i]['combo'] = array('#type' => 'markup',
        '#value' => $cells,
      );
      $form['table']['body'][$i]['combo_array'] = array('#type' => 'hidden', '#value' => $serial_array);
      $form['table']['body'][$i]['model'] = array('#type' => 'textfield',
        '#default_value' => $default_model,
        '#prefix' => '<td>',
        '#suffix' => '</td>',
      );
      ++$i;
    }
    
    $form['nid'] = array('#type' => 'hidden', '#value' => $nid);
    $form['submit'] = array('#type' => 'submit', '#value' => t('Submit'));
  }
  else{
    $form['error'] = array('#value' => t('There are no attributes associated with this product. Click "attributes" above to add some.'));
  }
  $form['pager'] = array('#value' => theme('pager'));
  return $form;
}

/**
 * Submit function for uc_product_adjustments_form().
 */
function uc_product_adjustments_form_submit($form_id, $form_values){
  foreach ($form_values['body'] as $value){
    if (!empty($value['model']) && $value['model'] != $form_values['default']){
      db_query("UPDATE {uc_product_adjustments} SET model = '%s' WHERE nid = %d AND combination = '%s'",
        $value['model'], $form_values['nid'], $value['combo_array']);
      if (!db_affected_rows()){
        db_query("INSERT INTO {uc_product_adjustments} (nid, combination, model) VALUES (%d, '%s', '%s')",
          $form_values['nid'], $value['combo_array'], $value['model']);
      }
    }
  }
  drupal_set_message(t('Product adjustments have been saved.'));
  $goto = array($_GET['q']);
  if ($_GET['page']){
    $goto[] = 'page='. $_GET['page'];
  }
  return $goto;
}

/******************************************************************************
 * Module Functions                                                           *
 ******************************************************************************/

/**
 * Load an attribute from the database.
 *
 * @param $attr_id
 *   The id of the attribute.
 * @param $nid
 *   Node id. If given, the attribute will have the options that have been
 *   assigned to that node for the attribute.
 */
function uc_attribute_load($attr_id, $nid = null, $type = ''){
  if ($nid){
    switch ($type){
      case 'product':
        $attribute = db_fetch_object(db_query("SELECT a.aid, a.name, a.ordering AS default_ordering, pa.default_option, pa.required, pa.ordering FROM {uc_attributes} AS a LEFT JOIN {uc_product_attributes} AS pa ON a.aid = pa.aid AND pa.nid = %d WHERE a.aid = %d ORDER BY pa.ordering", $nid, $attr_id));
        $result = db_query("SELECT po.nid, po.oid, po.cost, po.price, po.weight, po.ordering, ao.name, ao.aid FROM {uc_product_options} AS po LEFT JOIN {uc_attribute_options} AS ao ON po.oid = ao.oid AND nid = %d WHERE aid = %d ORDER BY po.ordering, ao.name", $nid, $attr_id);
      break;
      case 'class':
        $attribute = db_fetch_object(db_query("SELECT a.aid, a.name, a.ordering AS default_ordering, ca.default_option, ca.ordering FROM {uc_attributes} AS a LEFT JOIN {uc_class_attributes} AS ca ON a.aid = ca.aid AND ca.pcid = '%s' WHERE a.aid = %d ORDER BY ca.ordering", $nid, $attr_id));
        $result = db_query("SELECT co.pcid, co.oid, co.cost, co.price, co.weight, co.ordering, ao.name, ao.aid FROM {uc_class_attribute_options} AS co LEFT JOIN {uc_attribute_options} AS ao ON co.oid = ao.oid AND co.pcid = '%s' WHERE ao.aid = %d ORDER BY co.ordering, ao.name", $nid, $attr_id);
      break;
      default:
        $attribute = db_fetch_object(db_query("SELECT * FROM {uc_attributes} WHERE aid = %d", $attr_id));
        $result = db_query("SELECT * FROM {uc_attribute_options} WHERE aid = %d ORDER BY ordering, name", $attr_id);
      break;
    }
    if (isset($attribute->default_ordering) && is_null($attribute->ordering)){
      $attribute->ordering = $attribute->default_ordering;
    }
  }
  else{
    $attribute = db_fetch_object(db_query("SELECT * FROM {uc_attributes} WHERE aid = %d", $attr_id));
    $result = db_query("SELECT * FROM {uc_attribute_options} WHERE aid = %d ORDER BY ordering, name", $attr_id);
  }
  if ($attribute){
    $attribute->options = array();
    while ($option = db_fetch_object($result)){
      $attribute->options[$option->oid] = $option;
    }
    //uasort($attribute->options, '_uc_attribute_sort');
  }
  return $attribute;
}

/**
 * Load the option identified by $opt_id.
 */
function uc_attribute_option_load($opt_id){
  $result = db_query("SELECT * FROM {uc_attribute_options} WHERE oid = %d", $opt_id);
  return db_fetch_object($result);
}

/**
 * Load all attributes associated with a product node.
 */
function uc_product_get_attributes($nid){
  $result = db_query("SELECT aid FROM {uc_product_attributes} WHERE nid = %d ORDER BY ordering", $nid);
  $chosen_attr = array();
  while ($attr = db_fetch_object($result)){
    $chosen_attr[$attr->aid] = uc_attribute_load($attr->aid, $nid, 'product');
  }
  //uasort($chosen_attr, '_uc_attribute_sort');
  return $chosen_attr;
}

/**
 * Load all attributes associated with a product class.
 */
function uc_class_get_attributes($pcid){
  $result = db_query("SELECT aid FROM {uc_class_attributes} WHERE pcid = '%s' ORDER BY ordering", $pcid);
  $chosen_attr = array();
  while ($attr = db_fetch_object($result)){
    $chosen_attr[$attr->aid] = uc_attribute_load($attr->aid, $pcid, 'class');
  }
  uasort($chosen_attr, '_uc_attribute_sort');
  return $chosen_attr;
}

/**
 * Display formatted of data associated with attributes
 *
 * @param $type
 *   options | attributes
 *   Determines how to handle the $data array.
 * @param $data
 *   An array of attribute ids or option ids. If option ids, they are indexed by attribute ids.
 * @return
 *   HTML format of $data.
 *
 * @ingroup themeable
 */
function theme_uc_attribute($type, $data, $nid){
  if ($type == 'options' && is_array($data)){
    if (count($data)){
      $output = '<ul class="options">';
      foreach ($data as $aid => $oid){
        $attribute = uc_attribute_load($aid);
        $option = $attribute->options[$oid];
        $output .= '<li>'. $option->name .'</li>';
      }
      $output .= '</ul>';
    }
  }
  elseif ($type == 'attributes'){
    if (is_array($data) && count($data)){
      $output = '<div id="option_key">';
      foreach ($data as $aid){
        $output .= theme('uc_attribute_options', $aid, $nid);
      }
      $output .= '</div>';
    }
    elseif (is_numeric($data)){
      $output = '<div id="option_key">';
      $output .= theme('uc_attribute_options', $data);
      $output .= '</div>';
    }
  }
  return $output;
}

/**
 * Format an attribute and its options.
 *
 * @ingroup themeable
 */
function theme_uc_attribute_options($aid, $nid){
  $attribute = uc_attribute_load($aid, $nid, 'product');
  $output .= '<h2>'. $attribute->name .'</h2>';
  $rows = array();
  foreach ($attribute->options as $key => $input){
    $rows[] = array($input->oid, $input->name);
  }
  if (count($rows) == 0){
    $rows[] = array(array('data' => t('(To be determined by customer.)'), 'colspan' => '2'));
  }
  $header = array(t('Option ID'), t('Name'));
  $output .= theme('table', $header, $rows);
  return $output;
}

/**
 * Get the options chosen for a product that is in the cart.
 *
 * @param $item
 *   An element of the array returned by uc_cart_get_contents.
 * @return
 *   Array of options chosen by a customer, indexed by attribute ids. Each
 *   element stores the attribute name and the option object chosen.
 */
function _uc_cart_product_get_options($item){
  $options = array();
  $data = $item->data;
  if (!empty($data['attributes']) && is_array($data['attributes'])){
    foreach ($data['attributes'] as $aid => $oid){
      $attribute = uc_attribute_load($aid, $item->nid, 'product');
      if (count($attribute->options)){
        $options[$aid] = (array)$attribute->options[$oid];
        $options[$aid]['attribute'] = $attribute->name;
      }
      else{
        $options[$aid] = array('attribute' => $attribute->name,
          'oid' => 0,
          'name' => $oid,
          'cost' => 0,
          'price' => 0,
          'weight' => 0,
        );
      }
    }
  }
  else{
    $options = array();
  }
  return $options;
}

/**
 * Helper function for uc_attribute_form_alter()
 */
function _uc_attribute_alter_form($product){
  $result = db_query("SELECT * FROM {uc_product_attributes} WHERE nid = %d ORDER BY ordering", $product['nid']['#value']);
  $total_attributes = db_num_rows($result);
  if ($node = node_load((int)$product['nid']['#value'])){
    while ($relation = db_fetch_object($result)){
      $attribute = uc_attribute_load($relation->aid, $product['nid']['#value'], 'product');
      $opt_array = array();
      foreach($attribute->options as $option){
        switch (variable_get('uc_attribute_option_price_format', 'adjustment')){
          case 'total':
            $display_price = ', '. uc_currency_format($node->sell_price + $option->price);
            if ($total_attributes == 1){
              break;
            }
          case 'adjustment':
            $display_price = ($option->price != 0 ? ', '. ($option->price > 0 ? '+' : '') . uc_currency_format($option->price) : '');
          break;
          case 'none':
          default:
            $display_price = '';
          break;
        }
        $opt_array[$option->oid] = $option->name . $display_price;
      }
      if (count($attribute->options)){
        if($attribute->required) {
          $opt_array = array('' => 'Please select an option') + $opt_array;
          $relation->default_option = '';
        }
        $product['attributes'][$attribute->aid] = array('#type' => 'select',
          '#title' => $attribute->name,
          '#default_value' => $relation->default_option,
          '#options' => $opt_array,
          '#required' => $attribute->required,
        );
      }
      else{
        $product['attributes'][$attribute->aid] = array('#type' => 'textfield',
          '#title' => $attribute->name,
          '#required' => $attribute->required,
        );
      }
      $product['attributes']['#theme'] = 'uc_attribute_add_to_cart';
    }
  }
  return $product;
}

/**
 * usort() callback.
 */
function _uc_attribute_sort($a, $b){
  if ($a->ordering == $b->ordering){
    return 0;
  }
  else{
    return ($a->ordering < $b->ordering) ? -1 : 1;
  }
}