<?php

/**
 * @file
 * Administrative interface for Linked Field.
 */

/**
 * List all linked fields.
 *
 * @see field_ui_fields_list()
 */
function linked_field_field_list() {
  // Get all field config instances from database.
  $field_config_instances = db_select('field_config_instance', 'fci')->fields('fci')->execute();
  $linked_fields = array();

  foreach ($field_config_instances as $fci) {
    $field_name = $fci->field_name;
    $entity_type = $fci->entity_type;
    $bundle = $fci->bundle;
    $data = unserialize($fci->data);

    // Iterate the view modes.
    foreach ($data['display'] as $view_mode_name => $view_mode) {
      // Proceed only if the current field is linked.
      if (isset($view_mode['settings']['linked_field']) && $view_mode['settings']['linked_field']['linked']) {
        // Get some information about the field.
        $entity_info = entity_get_info($entity_type);
        $view_mode_path = ($view_mode_name != 'default') ? '/' . $view_mode_name : '';
        $admin = $entity_info['bundles'][$bundle]['admin']['real path'] . '/display' . $view_mode_path;
        $view_mode_label = ($view_mode_name != 'default') ? $entity_info['view modes'][$view_mode_name]['label'] : 'Default';
        $bundle_name = $entity_info['bundles'][$bundle]['label'];

        if (!isset($linked_fields[$field_name][$entity_type]['#label'])) {
          $linked_fields[$field_name][$entity_type]['#label'] = $entity_info['label'];
        }

        if (!isset($linked_fields[$field_name][$entity_type][$bundle]['#label'])) {
          $linked_fields[$field_name][$entity_type][$bundle]['#label'] = $bundle_name;
        }

        $linked_fields[$field_name][$entity_type][$bundle][$view_mode_name] = array(
          'admin' => $admin,
          'view_mode' => $view_mode_label,
        );

      }
    }
  }

  $header = array(t('Field name'), t('Linked in'));
  $rows = array();

  // Iterate all linked fields and build a table.
  foreach ($linked_fields as $field_name => $entity_types) {
    $rows[$field_name]['data'][0] = check_plain($field_name);
    $fieldsets = array();

    // Iterate all entity types.
    foreach ($entity_types as $entity_type => $bundles) {
      $entity_type_label = $bundles['#label'];
      $bundle_list = array();

      // Iterate all entity bundles.
      foreach (element_children($bundles) as $key) {
        $bundle_name = $bundles[$key]['#label'];

        $view_modes = $bundles[$key];

        $view_mode_list = array();

        // Iterate all bundle view modes.
        foreach (element_children($view_modes) as $key) {
          $view_mode = $view_modes[$key];
          $view_mode_list[] = l($view_mode['view_mode'], $view_mode['admin']);
        }

        $bundle_list[] = array(
          'data' => $bundle_name,
          'children' => $view_mode_list,
        );
      }

      // Add a new fieldst per entity type.
      $fieldsets[] = array(
        '#type' => 'fieldset',
        '#title' => $entity_type_label,
        '#children' => theme('item_list', array('items' => $bundle_list)),
        '#attributes' => array('class' => array('collapsible', 'collapsed')),
      );
    }

    drupal_add_library('system', 'drupal.collapse');
    $rows[$field_name]['data'][1] = drupal_render($fieldsets);
  }

  // Sort rows by field name.
  ksort($rows);
  $output = array(
    '#theme' => 'table',
    '#header' => $header,
    '#rows' => $rows,
    '#empty' => t('No fields are linked yet.'),
  );

  return $output;
}