<?php
// $Id$

/**
 * @file
 * Create complex, repeating groups of CCK fields that work in unison.
 *
 * @See README.txt.
 * 
 */

function multigroup_help($path, $arg) {
  switch ($path) {
    case ('admin/help#multigroup'): 
      return t('The fields in a Standard group are independent of each other and each can have either single or multiple values. The fields in a Multigroup are treated as a repeating collection of single value fields.');
  }
}

/**
 * Implementation of hook_init().
 */
function multigroup_init() {
  drupal_add_css(drupal_get_path('module', 'multigroup') .'/multigroup.css');
}

/**
 * Implementation of hook_theme().
 */
function multigroup_theme() {
  return array(
    'multigroup_node_form' => array(
      'arguments' => array('element' => NULL),
    ),
    'multigroup_node_label' => array(
      'arguments' => array('text' => NULL),
    ),
    'multigroup_display_simple' => array(
      'arguments' => array('element' => NULL),
    ),
    'multigroup_display_hr' => array(
      'arguments' => array('element' => NULL),
    ),
    'multigroup_display_table' => array(
      'arguments' => array('element' => NULL),
    ),
  );
}

/**
 * Implementation of hook_fieldgroup_types().
 */
function multigroup_fieldgroup_types() {
  return array('multigroup' => t('Multigroup'));
}

/**
 * Implementation of hook_fieldgroup_default_settings().
 */
function multigroup_fieldgroup_default_settings($group_type) {
  if ($group_type == 'multigroup') {
    module_load_include('inc', 'content', 'includes/content.admin');
    $settings = array('multigroup' => array('multiple' => 1));
    foreach (array_keys(content_build_modes()) as $key) {
      $settings['multigroup']['display_settings'][$key]['format'] = 'fieldset';
    }
    return $settings;
  }
}

function multigroup_multiple_values() {
  return array(
    //'' => t('N/A'), 
    1 => t('Unlimited'), 
    0 => 1) + drupal_map_assoc(range(2, 10));
}

/**
 * Implementation of hook_menu().
 */
function multigroup_menu() {
  $items = array();
  // Callback for AHAH add more buttons.
  $items['multigroup/js_add_more'] = array(
    'page callback' => 'multigroup_add_more_js',
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );
  return $items;
}

/**
 * Implementation of hook_form_alter().
 */
function multigroup_form_alter(&$form, $form_state, $form_id) {
  // If this is a field edit form and the field is in a Multigroup, 
  // override the multiple value settings.
  if ($form_id == 'content_field_edit_form' && isset($form['widget'])) {
    $content_type = content_types($form['type_name']['#value']);
    $groups = fieldgroup_groups($content_type['type']);
    $group_name = _fieldgroup_field_get_group($content_type['type'], $form['field_name']['#value']);
    $group = isset($groups[$group_name]) ? $groups[$group_name] : array();
    if (!empty($group) && $group['group_type'] == 'multigroup') {
      $form['field']['multiple']['#value'] = $group['settings']['multigroup']['multiple'];
      $form['field']['multiple']['#access'] = FALSE;
    }
  }
  elseif ($form_id == 'content_field_overview_form') {
    multigroup_field_overview_form($form, $form_state);
    $form['#validate'][] = 'multigroup_field_overview_form_validate';
  }
  elseif ($form_id == 'content_display_overview_form') {
    multigroup_display_overview_form($form, $form_state, $form_id);
    $form['#submit'] = array_merge(array('multigroup_display_overview_form_submit'), $form['#submit']);
  }
  elseif ($form_id == 'fieldgroup_group_edit_form') {
    return multigroup_group_edit_form($form, $form_state, $form_id);
  }
}

function multigroup_field_overview_form(&$form, &$form_state) {
  $options = fieldgroup_types();
  $options['standard'] = t('Standard: simple field collection');
  $options['multigroup'] = t('Multigroup: fields that move in unison');
  $form['_add_new_group']['group_type'] = array(
    '#type' => 'select',
    '#description' => t('Type of group.'),
    '#options' => $options,
    '#default_value' => 'standard',
  );
}

/**
 * Validation for creating/moving fields and groups on the 
 * Manage Fields screen.
 */
function multigroup_field_overview_form_validate($form, &$form_state) {
  $form_values = $form_state['values'];
  
  $type_name = $form['#type_name'];
  $fields = array();
  $groups = array();
    
  $group = $form_values['_add_new_group'];
  if (array_filter(array($group['label'], $group['group_name']))) {
    
    $group['settings'] = field_group_default_settings($form_values['_add_new_group']['group_type']);
    $group = $form_values['_add_new_group'];
    $validation = fieldgroup_validate_name($group);
    
    // If there's something wrong with the new group,
    // don't bother doing any more validation, further 
    // processing will be stopped by the fieldgroup module.
    if (!empty($validation['errors'])) {
      return;
    }
    $group['group_name'] = $validation['group_name'];
    $new_group_name = $group['group_name'];
    $groups['_add_new_group'] = $group;
  }
  
  // See if we have fields moving into or out of a Multigroup.
  // Set any fields to use the new name here so they will get processed
  // correctly by the fieldgroup module when saved.
  foreach ($form_values as $key => $values) {
    if ($values['parent'] == '_add_new_group') {
      $values['parent'] = $new_group_name;
      $form_values[$key] = $values;
    }
    
    if (!empty($form[$key]['#row_type']) && $form[$key]['#row_type'] == 'group') {
      // Gather up info about all groups.
      $group_name = $form_values[$key]['group']['group_name'];
      $groups[$group_name] = $form_values[$key]['group'];
    }
    if (!empty($form[$key]['#row_type']) && $form[$key]['#row_type'] == 'field') {
      if ($values['prev_parent'] != $values['parent']) {
        // Gather up fields that have moved in or out of a group.
        $fields[$key] = $form_values[$key]['field'];  
      }
    }
  }
  
  if (!empty($fields)) {
    foreach ($fields as $field_name => $field) {
      $new_group = $form_values[$field_name]['parent'];
      $old_group = $form_values[$field_name]['prev_parent'];
      if (!empty($new_group) && isset($groups[$new_group]) && $groups[$new_group]['group_type'] == 'multigroup') {
        $allowed_in = multigroup_allowed_in($field, $groups[$new_group]);
        if (!$allowed_in['allowed']) {
          form_set_error($field_name, $allowed_in['message']);  
        }
        else {
          if (!empty($allowed_in['message'])) {
            drupal_set_message($allowed_in['message']);
          }
          module_load_include('inc', 'content', 'includes/content.crud');
          $content_type = content_types($type_name);
          $multiple = $groups[$new_group]['settings']['multigroup']['multiple'];
          $field = $content_type['fields'][$field_name];
          $field['multiple'] = $multiple;
          $field = content_field_instance_collapse($field);
          content_field_instance_update($field);
          drupal_set_message(t('The field %field has been updated to use %multiple values, to match the multiple value setting of the Multigroup %group.', array(
            '%field' => $field['label'], '%multiple' => $multiple, '%group' => $groups[$new_group]['label'])));
        }
      }
      elseif (!empty($old_group) && isset($groups[$old_group]) && $groups[$old_group]['group_type'] == 'multigroup') {
        $allowed_out = multigroup_allowed_out($field, $groups[$old_group]);
        if (!$allowed_out['allowed']) {
          form_set_error($field_name, $allowed_out['message']);  
        }
        elseif (!empty($allowed_out['message'])) {
          drupal_set_message($allowed_out['message']);  
        }
      }
    }
  }
}

/**
 * Helper function for deciding if a field is 
 * allowed into a Multigroup.
 */
function multigroup_allowed_in($field, $group) {
  if ($group['group_type'] != 'multigroup') {
    return array('allowed' => TRUE, 'message' => '');
  }
  
  // We can't allow fields with more multiple values than the group has
  // to be moved into it.
  $max_existing = content_max_delta($field['field_name']);
  $group_max = $group['settings']['multigroup']['multiple'];
  if ($max_existing > $group_max) {
    return array(
      'allowed' => FALSE, 
      'message' => t('This change is not allowed. The field %field already has %multiple values in the database but the group %group only allows %group_max. Making this change would result in the loss of data.', array('%field' => $field['widget']['label'], '%multiple' => $max_existing, '%group' => $group['label'], '%group_max' => $group_max))
    );  
  }
  
  // Fields that handle their own multiple values may not have the same values
  // in Multigroup fields and normal fields. We don't know if they will work or not.
  
  // Adding a hook here where widgets that handle their own multiple values 
  // that will work correctly in Multigroups can allow their fields in.
  
  if (content_handle('widget', 'multiple values', $field) != CONTENT_HANDLE_CORE) {
    $allowed_widgets = array('optionwidgets_select', 'optionwidgets_buttons', 'optionwidgets_onoff');
    $allowed_widgets = array_merge($allowed_widgets, module_invoke_all('multigroup_allowed_widgets'));
    if (!in_array($field['widget']['type'], $allowed_widgets)) {
      return array(
        'allowed' => FALSE, 
        'message' => t('This change is not allowed. The field %field handles multiple values differently than the Content module. Making this change could result in the loss of data.', array('%field' => $field['widget']['label']))
      );
    } 
  }

  // Allow other modules to intervene.
  // Any failure will prevent this action.
  foreach (module_implements('multigroup_allowed_in') as $module) {
    $function = $module .'_multigroup_allowed_in';
    $result = $function($field, $group);
    if ($result['allowed'] === FALSE) {
      return array('allowed' => FALSE, 'message' => $result['message']);
    }
  }    
   
  $message = t('You are moving the field %field into a Multigroup.', array('%field' => $field['widget']['label']));
  return array('allowed' => TRUE, 'message' => $message);
}

/**
 * Helper function for deciding if a field is 
 * allowed out of a Multigroup.
 */
function multigroup_allowed_out($field, $group) {
  if ($group['group_type'] != 'multigroup') {
    return array('allowed' => TRUE, 'message' => '');
  }
  // Optionwidgets do not behave the same in a Multigroup field as out of it.
  // In a Multigroup the same option can be selected multiple times,
  // but that is not possible in a normal group.

  // Adding a hook here where widgets that handle their own multiple values 
  // can indicate their fields should not be removed from Multigroups.
  
  $max_existing = content_max_delta($field['field_name']);
  $no_remove_widgets = array('optionwidgets_select', 'optionwidgets_buttons', 'optionwidgets_onoff');
  $no_remove_widgets = array_merge($no_remove_widgets, module_invoke_all('multigroup_no_remove_widgets'));
  if (in_array($field['widget']['type'], $no_remove_widgets) && $max_existing > 0) {
    return array(
      'allowed' => FALSE, 
      'message' => t('This change is not allowed. The field %field already has data created and uses a widget that stores data differently in a Standard group than in a Multigroup. Making this change could result in the loss of data.', array('%field' => $field['widget']['label']))
    );  
  }
  
  // Allow other modules to intervene.
  // Any failure will prevent this action.
  foreach (module_implements('multigroup_allowed_out') as $module) {
    $function = $module .'_multigroup_allowed_out';
    $result = $function($field, $group);
    if ($result['allowed'] === FALSE) {
      return array('allowed' => FALSE, 'message' => $result['message']);
    }
  }    
   
  $message = t('You are moving the field %field out of a Multigroup.', array('%field' => $field['widget']['label']));
  return array('allowed' => TRUE, 'message' => $message);  
}

/**
 * Menu callback; presents a listing of fields display settings for a content type.
 *
 * Add an additional selector for setting multigroup field display format.
 */
function multigroup_display_overview_form(&$form, &$form_state) {
  
  $type_name = $form['#type_name'];
  $contexts_selector = $form['#contexts'];
  
  // Gather type information.
  $type = content_types($type_name);
  $field_types = _content_field_types();
  $fields = $type['fields'];

  $groups = $group_options = array();
  if (module_exists('fieldgroup')) {
    $groups = fieldgroup_groups($type['type']);
    $group_options = _fieldgroup_groups_label($type['type']);
  }
  $contexts = content_build_modes($contexts_selector);

  // Multigroups, extra values.
  $label_options = array(
    'above' => t('Above'),
    'hidden' => t('<Hidden>'),
  );
  $options = array(
    'none' => t('none'),
    'fieldset' => t('fieldset'),
    'hr' => t('horizontal line'),
    //'table' => t('table'), // TODO add this later
    'hidden' => t('<Hidden>'),
  );
  foreach ($groups as $name => $group) {
    if ($group['group_type'] != 'multigroup') {
      continue;
    }
    $defaults = $group['settings']['multigroup']['display_settings'];
    
    $form_name = $name .'_subgroup';
    $form['#fields'] = array_merge(array($form_name), $form['#fields']);
    $form[$form_name] = array(
      'human_name' => array('#value' => t('[Subgroup format]')),
      'weight' => array('#type' => 'value', '#value' => -20),
      'parent' => array('#type' => 'value', '#value' => $name),
    );
    if ($contexts_selector == 'basic') {
      $form[$form_name]['label'] = array(
        '#type' => 'select',
        '#options' => $label_options,
        '#default_value' => isset($defaults['label']) ? $defaults['label'] : 'above',
      );
    }
    foreach ($contexts as $key => $title) {
      $form[$form_name][$key]['format'] = array(
        '#type' => 'select',
        '#options' => $options,
        '#default_value' => isset($defaults[$key]) ? $defaults[$key] : 'fieldset',
      );
    }
  }
  return $form;
}

/**
 * Submit handler for the display overview form.
 * 
 * Do this in pre_save so we catch it before the content module
 * tries to use our 'field'.
 */
function multigroup_display_overview_form_submit($form, &$form_state) {
  $form_values = $form_state['values'];
    
  // Find any groups we inserted into the display fields form,
  // save our settings, and remove them from $form_state.
  foreach ($form_values as $key => $values) {
    if (in_array($key, $form['#fields']) && substr($key, -9) == '_subgroup') {
      $group_name = str_replace('_subgroup', '', $key);
      $groups = fieldgroup_groups($form['#type_name']);
      $group = $groups[$group_name];
          
      // We have some numeric keys here, so we can't use array_merge.
      foreach ($values as $k => $v) {
        $group['settings']['multigroup']['display_settings'][$k] = $v;
      }
      fieldgroup_save_group($form['#type_name'], $group);
      
      // Make sure group information is immediately updated.
      cache_clear_all('fieldgroup_data', content_cache_tablename());
      fieldgroup_groups('', FALSE, TRUE);
      unset($form_state['values'][$key]);
    }
  }
}

/**
 * Alter the Fieldgroup edit form 
 * to add Multigroup settings.
 */
function multigroup_group_edit_form(&$form, &$form_state) {
  $type_name = $form['#content_type']['type'];
  $group_name = $form['group_name']['#default_value'];
  
  $content_type = content_types($type_name);
  $groups = fieldgroup_groups($content_type['type']);
  $group = $groups[$group_name];
  
  if ($group['group_type'] != 'multigroup') {
    return;
  }

  module_load_include('inc', 'content', 'includes/content.admin');
  module_load_include('inc', 'content', 'includes/content.crud');
  $form['group_type'] = array(
    '#type' => 'hidden',
    '#value' => $group['group_type'],
    );
  $form['settings']['multigroup'] = array(
    '#type' => 'fieldset',
    '#title' => t('Other settings'),
    '#collapsed' => FALSE,
    '#collapsible' => TRUE,
  );
  
  $description = t('Number of times to repeat the collection of Multigroup fields.') . ' ';
  $description .= t("'Unlimited' will provide an 'Add more' button so the users can add repeat it as many times as they like.") . ' ';
  $description .= t('All fields in this group will automatically be set to allow this number of values.');
    
  $multiple = isset($group['settings']['multigroup']['multiple']) ? $group['settings']['multigroup']['multiple'] : 1;
  $form['settings']['multigroup']['multiple'] = array(
    '#tree' => TRUE,
    '#type' => 'select',
    '#title' => t('Number of repeats'),
    '#options' => multigroup_multiple_values(),
    '#default_value' => $multiple,
    '#description' => $description,
  );

  $form['settings']['multigroup']['labels'] = array(
    '#type' => 'fieldset',
    '#title' => t('Labels'),
    '#description' => t("Labels for each subgroup of fields. Labels can be hidden or shown in various contexts using the 'Display fields' screen."),
  );
  if ($multiple < 2) {
    $multiple = 0;
  }
  for ($i = 0; $i < 10; $i++) {
    $form['settings']['multigroup']['labels'][$i] = array(
      '#type' => 'textfield',
      '#title' => t('Subgroup %number label', array('%number' => $i + 1)),
      '#default_value' => isset($group['settings']['multigroup']['labels'][$i]) ? $group['settings']['multigroup']['labels'][$i] : '',
    );
  }
  
  $form['#validate'][] = 'multigroup_group_edit_form_validate';
  $form['#submit'][] = 'multigroup_group_edit_form_submit';
  return $form;
}

/**
 * Validate the Fieldgroup edit form.
 */
function multigroup_group_edit_form_validate($form, &$form_state) {
  $form_values = $form_state['values'];
  $group_type = $form_values['group_type'];
  if ($group_type != 'multigroup') {
    return;
  }
  $content_type = $form['#content_type'];
  $groups = fieldgroup_groups($content_type['type']);
  $group = $groups[$form_values['group_name']];
  foreach ($group['fields'] as $field_name => $data) {
    // Make sure we don't set the multiple values to a number that
    // would result in lost data.
    $max_existing = content_max_delta($field_name);
    if ($form_values['settings']['multigroup']['multiple'] != 1 
      && $max_existing > $form_values['settings']['multigroup']['multiple']) {
      form_set_error('settings][multigroup][multiple', t('The field %field in this group already has %multiple values in the database. To prevent the loss of data you cannot set the number of Multigroup values to less than this.', array('%field' => $data['label'], '%multiple' => $max_existing)));
    }
  }
}

/**
 * Submit the Fieldgroup edit form.
 * 
 * Update multiple values of fields contained in Multigroups.
 */
function multigroup_group_edit_form_submit($form, &$form_state) {
  $form_values = $form_state['values'];
  $group_type = $form_values['group_type'];
  if ($group_type != 'multigroup') {
    return;
  }
  module_load_include('inc', 'content', 'includes/content.crud');
  $content_type = $form['#content_type'];
  $groups = fieldgroup_groups($content_type['type']);
  $group = $groups[$form_values['group_name']];
  $multiple = $form_values['settings']['multigroup']['multiple'];
  foreach ($group['fields'] as $field_name => $data) {
    $field = $content_type['fields'][$field_name];
    $field['multiple'] = $multiple;
    $field = content_field_instance_collapse($field);
    content_field_instance_update($field);
  }
}

/**
 * Implementation of hook_fieldgroup_form().
 * 
 * Align the delta values of each field in the Multigroup.
 * 
 * Swap the field name and delta for each Multigroup so we can 
 * d-n-d each collection of fields as a single delta item.
 */
function multigroup_fieldgroup_form(&$form, &$form_state, $form_id, $group) {
  if ($group['group_type'] != 'multigroup' || 
    !empty($form[$group['group_name']]['#access']) || empty($form[$group['group_name']])) {
    return;
  }
  $node = $form['#node'];
  $fields = $group['fields'];
  $content_fields = content_fields();
  $group_name = $group['group_name'];
  
  // Use the first field in the group to get the item counts.
  $first_field_name = array_shift(array_keys($group['fields']));
  $first_field = isset($content_fields[$first_field_name]) ? $content_fields[$first_field_name] : array();
  $first_field_items = isset($node->$first_field_name) ? $node->$first_field_name : array();
  
  $group['multiple'] = $group['settings']['multigroup']['multiple'];
  switch ($group['multiple']) {
    case 0:
      $max = 0;
      break;
    case 1:
      $filled_items = content_set_empty($first_field, $first_field_items);
      $current_item_count = isset($form_state['item_count'][$group_name])
                            ? $form_state['item_count'][$group_name]
                            : count($first_field_items);
      // We always want at least one empty icon for the user to fill in.
      $max = ($current_item_count > count($filled_items))
              ? $current_item_count - 1
              : $current_item_count;

      break;
    default:
      $max = $group['multiple'] - 1;
      break;
  }
  
  $form[$group_name]['#theme'] = 'multigroup_node_form';
  $form[$group_name]['#multiple'] = !empty($max);
  $form[$group_name]['#type_name'] = $group['type_name'];
  $form[$group_name]['#group_name'] = $group_name;
  $form[$group_name]['#group_label'] = $group['label'];
  $form[$group_name]['#element_validate'] = array('multigroup_node_form_validate');
  $form[$group_name]['#tree'] = TRUE;
      
  for ($delta = 0; $delta <= $max; $delta++) {
    multigroup_group_form($form, $form_state, $group, $delta);
  }
  
  // Unset the original group field values now that we've moved them.
  foreach ($fields as $field_name => $field) {
    unset($form[$group_name][$field_name]);
  }

  if ($add_more = multigroup_add_more($form, $form_state, $group)) {
    $form[$group_name] += $add_more;
  }
}

/**
 * Create a new delta value for the group.
 * 
 * Called in form_alter and by AHAH add more.
 */
function multigroup_group_form(&$form, &$form_state, $group, $delta) {
  if ($group['group_type'] != 'multigroup' || 
    !empty($form[$group['group_name']]['#access']) || empty($form[$group['group_name']])) {
    return;
  }
  module_load_include('inc', 'content', 'includes/content.node_form');
  
  $node = $form['#node'];
  $fields = $group['fields'];
  $content_fields = content_fields();
  $group_name = $group['group_name'];
  $group['multiple'] = $group['settings']['multigroup']['multiple'];
  $form[$group_name]['#fields'] = array_keys($group['fields']);
  
  foreach ($fields as $field_name => $group_field) {
    if (empty($form[$group_name][$delta])) {
      $form[$group_name] += array($delta => array($field_name => array()));
    }
    else {
      $form[$group_name][$delta][$field_name] = array();
    }
     
    $form[$group_name][$delta]['_weight'] = array(
      '#type' => 'weight',
      '#delta' => $delta, // this 'delta' is the 'weight' element's property
      '#default_value' => $delta,
      '#weight' => 100,
    );
    $form[$group_name][$delta]['_delta'] = array(
      '#type' => 'hidden',
      '#value' => $delta,
    );

    
    $field = $content_fields[$field_name];
      
    // Make each field into a pseudo single value field 
    // with the right delta value.
      
    $field['multiple'] = FALSE;
    $form['#field_info'][$field_name] = $field;
    $node_copy = drupal_clone($node);
      
    // Set the form '#node' to the delta value we want so the Content
    // module will feed the right $items to the field module in 
    // content_field_form().
      
    // There may be missing delta values for fields that were 
    // never created, so check first.
    if (!empty($node->$field_name) && count($node->$field_name) >= $delta + 1) {
      $node_copy->$field_name = array($delta => $node->{$field_name}[$delta]);
    }
    else {
      $node_copy->$field_name = array($delta => NULL);
    }
    $form['#node'] = $node_copy;
    $field_form = content_field_form($form, $form_state, $field, $delta);
              
    // Place the new $field_form into the $delta position in the group form.
    if (content_handle('widget', 'multiple values', $field) == CONTENT_HANDLE_CORE) {
      $value = array_key_exists($delta, $field_form[$field_name]) ? $delta : 0;
      $form[$group_name][$delta][$field_name] = $field_form[$field_name][$value];
    }
    else {
      $form[$group_name][$delta][$field_name] = $field_form[$field_name];
    }
    $form[$group_name][$delta][$field_name]['#weight'] = $field['widget']['weight'];
      
    // Add in our validation step, and make sure it preceeds other 
    // processing so we can massage the element back to the normal position.
    if (empty($form[$group_name][$delta][$field_name]['#element_validate'])) {
      $form[$group_name][$delta][$field_name]['#element_validate'] = array();
    }
    array_unshift($form[$group_name][$delta][$field_name]['#element_validate'], 'multigroup_node_item_validate');
  }

  // Reset the form '#node' back to its original value.
  $form['#node'] = $node;
  
  return $form;  
}

/**
 * Swap transposed field/delta values back 
 * to their normal positions in the node.
 */
function multigroup_node_item_validate($element, &$form_state) {
  static $weights = array();
  
  //dsm($form_state['values']); 
  $form_values = $form_state['values'];
  $field_name = array_pop($element['#parents']);
  $delta = array_pop($element['#parents']);
  $group_name = array_pop($element['#parents']);
    
  // Identify the new delta value for each field.
  
  // Find the original delta values for this group, save as static value 
  // because the group will acquire and lose values while we process it.
  if (!array_key_exists($group_name, $weights)) {
    $items = $form_state['values'][$group_name];
    $weights[$group_name] = array();
    foreach ($items as $count => $value) {
      // Allow for the possibility of matching _weights and missing deltas.
      $weight = floatval($value['_weight']);
      $old_delta = intval($value['_delta']);
      if (empty($weights[$group_name][$weight]) || !in_array($old_delta, $weights[$group_name][$weight])) {
        $weights[$group_name][$weight][] = $old_delta;
      }
    }
    ksort($weights[$group_name]);
  }
  $count = 0;
  foreach ($weights[$group_name] as $weight => $values) {
    foreach ($values as $old_delta) {
      if ($old_delta === $delta) {
        $delta = $count;
        //dsm('moving delta values: '.$group_name.'>'.$field_name.'>'.'from '. $old_delta .' to '. $delta);
        break 2;
      }
      $count++;
    }
  }
  // We figured out what the new order for the fields is, 
  // so set the value for the new delta.
  
  // We move these new values back up to the top level of the
  // node and out of the group so the Content module will find and
  // save the new values and so they don't get mixed into the
  // remaining, unaltered, values in the group.
  array_push($element['#parents'], $field_name);
  array_push($element['#parents'], $delta);
  
  // It's very important to use $form_values instead of $element['#value']
  // here, because $element['#value'] is sometimes missing changes
  // made in #element_validate processing done by other modules.
  $value = isset($form_values[$group_name][$delta][$field_name]) ? $form_values[$group_name][$delta][$field_name] : NULL;
  
  // Fields that use optionwidgets have an extra array level in the value
  // because of the optionwidgets transposition that forces a delta value 
  // into the result array. This works fine when a delta value is between
  // the field name and the field value, as in normal nodes, but not when 
  // we reverse the field and the delta, so in this case we need to 
  // promote the nested delta value back up to the field level.
  if (is_array($value) && multigroup_uses_optionwidgets($field_name, $element['#type_name'])) {
    $value = array_shift($value);
  }
  
  //dsm('setting value of '. $field_name.'>'.$delta);
  //dsm($value);
  form_set_value($element, $value, $form_state);
}

/**
 * Helper function for identifying fields that use
 * optionwidgets transpositions.
 */
function multigroup_uses_optionwidgets($field_name, $type_name) {
  //static $optionwidgets;
  if (empty($optionwidgets)) {
    $optionwidgets = array(
      'optionwidgets_select', 
      'optionwidgets_buttons', 
      'optionwidgets_onoff', 
      //'nodereference_autocomplete', 
      'nodereference_buttons', 
      'nodereference_select', 
      //'userreference_autocomplete', 
      'userreference_buttons', 
      'userreference_select',
      );
    // Add hook where other widgets that use optionwidgets can announce it.
    $optionwidgets = array_merge($optionwidgets, module_invoke_all('multigroup_uses_optionwidgets'));  
  }
    
  $types = content_types($type_name);
  $fields = $types['fields'];
  $field = $fields[$field_name];
  if (in_array($field['widget']['type'], $optionwidgets)) {
    return TRUE;
  }
  return FALSE;
}

/**
 * Validation for the whole node group.
 */
function multigroup_node_form_validate($element, $form_state) {
  // We moved all the new field values out of the field group
  // and up to the top level of the node, now get rid of the 
  // original group values.
  form_set_value($element, NULL, $form_state);
  return;
}

/**
 * Implementation of hook_fieldgroup_view().
 */
function multigroup_fieldgroup_view(&$node, &$element, $group, $context) {
  if ($group['group_type'] != 'multigroup') {
    return;
  }
          
  $group_name = $group['group_name'];
  $node_copy = drupal_clone($node);
  $max = $group['settings']['multigroup']['multiple'];
  
  $count = 0;
  foreach ($group['fields'] as $field_name => $field) {
    $count = max($count, count($node->$field_name));
  }
  
  $group['multiple'] = isset($group['settings']['multigroup']['multiple']) ? $group['settings']['multigroup']['multiple'] : 1;
  $labels = isset($group['settings']['multigroup']['labels']) ? $group['settings']['multigroup']['labels'] : array();
  $format = isset($group['settings']['multigroup']['display_settings'][$context]['format']) ? $group['settings']['multigroup']['display_settings'][$context]['format'] : 'fieldset';
  $show_label = isset($group['settings']['multigroup']['display_settings']['label']) ? $group['settings']['multigroup']['display_settings']['label'] : 'above';

  switch ($group['multiple']) {
    case 0:
      $max = 0;
      break;
    case 1:
      $max = $count;
      break;
    default:
      $max = $group['multiple'];
      break;
  }
  
  for ($delta = 0; $delta < $max; $delta++) {
    $element[$delta] = array('#weight' => $delta);
    
    $label = !empty($labels[$delta]) && $show_label == 'above' ? $labels[$delta] : '';
    
    foreach ($group['fields'] as $field_name => $field) {
              
      // Create a pseudo node that only has the value we want
      // in this group and pass it to the formatter.
      if (isset($node->content[$field_name])) {
        $node_copy->content[$field_name]['field']['items'] = array(
          $delta => isset($node->content[$field_name]['field']['items'][$delta]) ? $node->content[$field_name]['field']['items'][$delta] : NULL,
          );
        $element[$delta][$field_name] = $node_copy->content[$field_name];
        $element[$delta][$field_name]['#delta'] = $delta;
      }
    }
    switch ($format) {
      case 'table':
        $element[$delta]['#theme'] = 'multigroup_display_table';
        $element[$delta]['#title'] = $label;
        break;
      case 'fieldset':
        $element[$delta]['#type'] = 'fieldset';
        $element[$delta]['#title'] = $label;
        break;
      case 'hr':
        $element[$delta]['#theme'] = 'multigroup_display_hr';
        $element[$delta]['#title'] = $label;
        break;  
      default:
        $element[$delta]['#theme'] = 'multigroup_display_simple';
        $element[$delta]['#title'] = $label;
        break;
    }
          
  }
  
  foreach ($group['fields'] as $field_name => $field) {
    if (isset($element[$field_name])) {
      unset($element[$field_name]);
    }
  }
}

/**
 * Theme an individual form element.
 *
 * Combine multiple values into a table with drag-n-drop reordering.
 */
function theme_multigroup_node_form($element) {
  $output = '';
  if ($element['#multiple'] >= 1) {
    $table_id = $element['#group_name'] .'_values';
    $order_class = $element['#group_name'] .'-delta-order';
    
    $header = array(
      array(
        'data' => '',
        'colspan' => 2
      ),
      t('Order'),
    );
    $rows = array();
    $groups = fieldgroup_groups($element['#type_name']);
    $group = $groups[$element['#group_name']];
    $labels = isset($group['settings']['multigroup']['labels']) ? $group['settings']['multigroup']['labels'] : array();
    $multiple = isset($group['settings']['multigroup']['multiple']) ? $group['settings']['multigroup']['multiple'] : 1;
    
    $i = 0;
    foreach (element_children($element) as $delta => $key) {
      if ($key !== $element['#group_name'] .'_add_more') {
        $label = !empty($labels[$i]) ? theme('multigroup_node_label', $labels[$i]) : '';
        $element[$key]['_weight']['#attributes']['class'] = $order_class;
        $delta_element = drupal_render($element[$key]['_weight']);
        $cells = array(
          array('data' => '', 'class' => 'content-multiple-drag'),
          $label . drupal_render($element[$key]),
          array('data' => $delta_element, 'class' => 'delta-order'),
        );
        $rows[] = array(
          'data' => $cells,
          // TODO Tablesort drag n drop is not working with complex 
          // field validation. The fields appear to work correctly,
          // but element validation seems to get missed or confused 
          // causing validation errors. Need to investigate why.
          //'class' => 'draggable', 
        );
      }
      $i++;
    }

    $output .= theme('table', $header, $rows, array('id' => $table_id, 'class' => 'content-multiple-table'));
    $output .= $element['#description'] ? '<div class="description">'. $element['#description'] .'</div>' : '';
    $output .= drupal_render($element[$element['#group_name'] .'_add_more']);

    drupal_add_tabledrag($table_id, 'order', 'sibling', $order_class);
  }
  else {
    foreach (element_children($element) as $key) {
      $output .= drupal_render($element[$key]);
    }
  }

  return $output;
}

function multigroup_add_more(&$form, &$form_state, $group) {
  // Add AHAH add more button, if not working with a programmed form.
  $multiple = $group['settings']['multigroup']['multiple'];
  $form_element = array();
  if ($multiple != 1 || !empty($form['#programmed'])) {
    return $form_element;
  }
  else {
    // Make sure the form is cached so ahah can work.
    $form['#cache'] = TRUE;
    $content_type = content_types($group['type_name']);
    $group_name = $group['group_name'];
    $group_name_css = str_replace('_', '-', $group_name);

    $form_element[$group_name .'_add_more'] = array(
      '#type' => 'submit',
      '#name' => $group_name .'_add_more',
      '#value' => t('Add more values'),
      '#weight' => $multiple + 1,
      // Submit callback for disabled JavaScript. drupal_get_form() might get
      // the form from the cache, so we can't rely on content_form_alter()
      // including this file. Therefore, call a proxy function to do this.
      '#submit' => array('multigroup_add_more_submit_proxy'),
      '#ahah' => array(
        'path' => 'multigroup/js_add_more/'. $content_type['url_str'] .'/'. $group_name,
        'wrapper' => $group_name_css .'-items',
        'method' => 'replace',
        'effect' => 'fade',
      ),
      // When JS is disabled, the content_add_more_submit handler will find
      // the relevant field using these entries.
      '#group_name' => $group_name,
      '#type_name' => $group['type_name'],
    );

    // Add wrappers for the group and 'more' button.
    // TODO: could be simplified ?
    $form_element['#prefix'] = '<div class="clear-block" id="'. $group_name_css .'-add-more-wrapper"><div id="'. $group_name_css .'-items">';
    $form_element[$group_name .'_add_more']['#prefix'] = '<div class="content-add-more">';
    $form_element[$group_name .'_add_more']['#suffix'] =  '</div></div></div>';
  }
  return $form_element;
}

/**
 * Submit handler to add more choices to a content form. This handler is used when
 * JavaScript is not available. It makes changes to the form state and the
 * entire form is rebuilt during the page reload.
 */
function multigroup_add_more_submit($form, &$form_state) {
  // Set the form to rebuild and run submit handlers.
  node_form_submit_build_node($form, $form_state);
  $group_name = $form_state['clicked_button']['#group_name'];
  $type_name = $form_state['clicked_button']['#type_name'];

  // Make the changes we want to the form state.
  if ($form_state['values'][$group_name][$group_name .'_add_more']) {
    $form_state['item_count'][$group_name] = count($form_state['values'][$group_name]);
  }
}

/**
 * Menu callback for AHAH addition of new empty widgets.
 * 
 * Adapted from content_add_more_js to work with groups instead of fields.
 */
function multigroup_add_more_js($type_name_url, $group_name) {
  $type = content_types($type_name_url);
  $groups = fieldgroup_groups($type['type']);
  $group = $groups[$group_name];
  $group['multiple'] = $group['settings']['multigroup']['multiple'];
  
  if (($group['multiple'] != 1) || empty($_POST['form_build_id'])) {
    // Invalid request.
    drupal_json(array('data' => ''));
    exit;
  }

  // Retrieve the cached form.
  $form_state = array('submitted' => FALSE);
  $form_build_id = $_POST['form_build_id'];
  $form = form_get_cache($form_build_id, $form_state);
  if (!$form) {
    // Invalid form_build_id.
    drupal_json(array('data' => ''));
    exit;
  }

  // We don't simply return a new empty widget to append to existing ones, because
  // - ahah.js won't simply let us add a new row to a table
  // - attaching the 'draggable' behavior won't be easy
  // So we resort to rebuilding the whole table of widgets including the existing ones,
  // which makes us jump through a few hoops.

  // The form that we get from the cache is unbuilt. We need to build it so that
  // _value callbacks can be executed and $form_state['values'] populated.
  // We only want to affect $form_state['values'], not the $form itself
  // (built forms aren't supposed to enter the cache) nor the rest of $form_data,
  // so we use copies of $form and $form_data.
  $form_copy = $form;
  $form_state_copy = $form_state;
  $form_copy['#post'] = array();
  form_builder($_POST['form_id'], $form_copy, $form_state_copy);
  // Just grab the data we need.
  $form_state['values'] = $form_state_copy['values'];
  // Reset cached ids, so that they don't affect the actual form we output.
  form_clean_id(NULL, TRUE);

  // Sort the $form_state['values'] we just built *and* the incoming $_POST data
  // according to d-n-d reordering.
  unset($form_state['values'][$group_name][$group['group_name'] .'_add_more']);
  foreach ($_POST[$group_name] as $delta => $item) {
    $form_state['values'][$group_name][$delta]['_weight'] = $item['_weight'];
    $form_state['values'][$group_name][$delta]['_delta'] = $item['_delta'];
  }
  $form_state['values'][$group_name] = _content_sort_items($group, $form_state['values'][$group_name]);
  $_POST[$group_name] = _content_sort_items($group, $_POST[$group_name]);

  // Build our new form element for the whole group, asking for one more element.
  
  $form_state['item_count'] = array($group_name => count($_POST[$group_name]) + 1);
  $delta = max(array_keys($_POST[$group_name])) + 1;
  multigroup_group_form($form, $form_state, $group, $delta);
  
  // Save the new definition of the form.
  $form_state['values'] = array();
  form_set_cache($form_build_id, $form, $form_state);

  // Build the new form against the incoming $_POST values so that we can
  // render the new element.
  $_POST[$group_name][$delta]['_weight'] = $delta;
  $form_state = array('submitted' => FALSE);
  $form += array(
    '#post' => $_POST,
    '#programmed' => FALSE,
  );
  $form = form_builder($_POST['form_id'], $form, $form_state);

  // Render the new output.
  $group_form = $form[$group_name];
  
  // We add a div around the new content to receive the ahah effect.
  $group_form[$delta]['#prefix'] = '<div class="ahah-new-content">'. (isset($group_form[$delta]['#prefix']) ? $group_form[$delta]['#prefix'] : '');
  $group_form[$delta]['#suffix'] = (isset($group_form[$delta]['#suffix']) ? $group_form[$delta]['#suffix'] : '') .'</div>';

  // If a newly inserted widget contains AHAH behaviors, they normally won't
  // work because AHAH doesn't know about those - it just attaches to the exact
  // form elements that were initially specified in the Drupal.settings object.
  // The new ones didn't exist then, so we need to update Drupal.settings
  // by ourselves in order to let AHAH know about those new form elements.
  $javascript = drupal_add_js(NULL, NULL);
  $output_js = isset($javascript['setting']) ? '<script type="text/javascript">jQuery.extend(Drupal.settings, '. drupal_to_js(call_user_func_array('array_merge_recursive', $javascript['setting'])) .');</script>' : '';

  $output = theme('status_messages') . drupal_render($group_form) . $output_js;
  drupal_json(array('status' => TRUE, 'data' => $output));
  exit;
}

/**
 * Theme the sub group label in the node form.
 */
function theme_multigroup_node_label($text) {
  if (!empty($text)) {
    return '<h3>'. check_plain($text) .'</h3>';
  }
}

function theme_multigroup_display_simple($element) {
  $label = '';
  if (!empty($element['#title'])) {
    $label .= '<label class="multigroup">'. $element['#title'] .':</label>';
  }
  $output = $label;
  foreach (element_children($element) as $key) {
    $output .= drupal_render($element[$key]);
  }
  return $output;
}

function theme_multigroup_display_hr($element) {
  $label = '';
  if (!empty($element['#title'])) {
    $label .= '<label class="multigroup">'. $element['#title'] .':</label>';
  }
  $output = '<hr class="multigroup" />'. $label;
  foreach (element_children($element) as $key) {
    $output .= drupal_render($element[$key]);
  }
  return $output;
}

function theme_multigroup_display_table($element) {
  $label = '';
  if (!empty($element['#title'])) {
    $label .= '<label class="multigroup">'. $element['#title'] .':</label>';
  }
  $output = $label;
  foreach (element_children($element) as $key) {
    $output .= drupal_render($element[$key]);
  }
  return $output;
}