<?php

/**
 * Implements hook_entity_info().
 */
function cer_entity_info() {
  $info = array(
    'cer' => array(
      'label' => t('CER Preset'),
      'entity class' => 'CerPreset',
      'controller class' => 'CerPresetController',
      'base table' => 'cer_preset',
      'label callback' => 'entity_class_label',
      'module' => 'cer',
      'fieldable' => TRUE,
      'entity keys' => array(
        'id' => 'pid',
        'name' => 'identifier', // This is the automatically generated export key.
        'label' => 'identifier',  // The identifier will be the default label.
      ),
      'admin ui' => array(
        'path' => 'admin/config/content/cer',
        'file' => 'cer.admin.inc',
        'controller class' => 'CerUIController',
      ),
      'exportable' => TRUE,
      'features controller class' => 'CerPresetFeaturesController',
      'access callback' => 'cer_access',
    ),
  );

  if (variable_get('cer_enable_field_ui', FALSE)) {
    $info['cer']['bundles']['cer']['admin']['path'] = $info['cer']['admin ui']['path'];
  }

  return $info;
}

/**
 * Access callback for Entity UI.
 */
function cer_access($op, $preset = NULL, $account = NULL) {
  return user_access('administer cer settings', $account);
}

/**
 * Implements hook_menu().
 */
function cer_menu() {
  $info = cer_entity_info();
  $prefix = $info['cer']['admin ui']['path'];

  return array(
    "{$prefix}/update" => array(
      'title' => 'Bulk Update',
      'page callback' => 'drupal_get_form',
      'page arguments' => array('cer_bulk_update_form'),
      'access arguments' => array('administer cer settings'),
      'file' => 'cer.admin.inc',
      'type' => MENU_LOCAL_TASK,
    ),
  );

  return $items;
}

/**
 * Implements hook_permission().
 */
function cer_permission() {
  return array(
    'administer cer settings' => array(
      'title' => t('Administer corresponding references'),
    )
  );
}

/**
 * Implements hook_field_delete_instance().
 */
function cer_field_delete_instance(array $instance) {
  // Delete every CER preset which refers to the deleted field instance.
  $filter = $instance['entity_type'] . ':' . $instance['bundle'] . ':' . $instance['field_name'];

  $baseQuery = new EntityFieldQuery();
  $baseQuery->entityCondition('entity_type', 'cer');
  $baseQuery->fieldCondition('cer_enabled', 'value', TRUE);

  $query = clone $baseQuery;
  $query->fieldCondition('cer_left', 'path', $filter, 'CONTAINS');
  $result = $query->execute();
  if (isset($result['cer'])) {
    foreach (entity_load('cer', array_keys($result['cer'])) as $preset) {
      $preset->delete();
    }
  }

  $query = clone $baseQuery;
  $query->fieldCondition('cer_right', 'path', $filter, 'CONTAINS');
  $result = $query->execute();
  if (isset($result['cer'])) {
    foreach (entity_load('cer', array_keys($result['cer'])) as $preset) {
      $preset->delete();
    }
  }
}

/**
 * Implements hook_node_insert().
 */
function cer_node_insert(StdClass $node) {
  // Write access grants *before* doing CER stuff in order to prevent a race condition.
  // This tricky bug can easily rear its ugly head if you have an Entity Reference field,
  // referencing nodes, and a node access module enabled.
  //
  // Entity Reference's bundled selection handlers will use either EntityFieldQuery or 
  // Views, both of which are affected by node access grants (and rightfully so). 
  // However, when creating a node, core invokes hook_node_save() *before* it writes the 
  // grants to the database, which can cause EntityFieldQuery (or Views, unless 
  // configured to disable SQL rewriting) to return no results if the user isn't the 
  // superuser. Since CER asks the field backend to validate the reference, this can
  // cause the reference to not be validated, and the cross-reference to fail.
  //
  // Really, this is a core issue and not a CER issue. Core should be invoking
  // hook_node_save() AFTER it writes access info. But we can work around it by writing
  // the access info, doing our own processing, and then clearing the access info
  // so node_save() can write it cleanly. And that's what this does.
  //
  // Hear that, core devs? Fix it fix it fix it!
  //
  node_access_acquire_grants($node);
  cer_processing_entity('insert', $node, 'node');
  db_delete('node_access')->condition('nid', $node->nid)->execute();
}

/**
 * Implements hook_entity_insert().
 */
function cer_entity_insert($entity, $type) {
  if (! function_exists("cer_{$type}_insert")) {
    cer_processing_entity('insert', $entity, $type);
  }
}

/**
 * Implements hook_entity_update().
 */
function cer_entity_update($entity, $type) {
  if (! function_exists("cer_{$type}_update")) {
    cer_processing_entity('update', $entity, $type);
  }
}

/**
 * Implements hook_entity_delete().
 */
function cer_entity_delete($entity, $type) {
  if (! function_exists("cer_{$type}_delete")) {
    cer_processing_entity('delete', $entity, $type);
  }
}

/**
 * Process a entity's corresponding entity references.
 *
 * @param string $op 
 *  The operation being performed on the entity (insert, update, or delete).
 *
 * @param object $entity
 *  The entity object (optionally wrapped), or its ID.
 *
 * @param string $entity_type
 *  The entity type. If $entity is wrapped, this can be NULL since the entity
 *  type is known by the wrapper.
 *
 * @param array $context
 *  Either the Batch API context (since this is the callback function used
 *  during bulk update) or NULL if we're not in a batch job.
 */
function cer_processing_entity($op, $entity, $entity_type = NULL, array &$context = NULL) {
  // Don't do anything if the MAINTENANCE_MODE flag is set. This isn't the same thing
  // as user-facing maintenance mode, but rather is set when running, say, update.php
  // or another relatively low-level operation. This was added to prevent CER from
  // running while updating from 1.x or 2.x, since classes may not yet be registered
  // yet and we don't want to cause fatal errors during update.
  if (defined('MAINTENANCE_MODE')) {
    return;
  }

  // Don't process anything that hasn't got the cer data structure: this provides an
  // opportunity for other modules to opt their entities out of CER processing.
  if ($entity instanceof EntityStructureWrapper) {
    try {
      // If there is no such a property an exception will be thrown.
      $entity->getPropertyInfo('cer');
    }
    catch (EntityMetadataWrapperException $e) {
      return;
    }
  }

  if ($entity instanceof EntityDrupalWrapper) {
    // Under certain circumstances, the cer struct may not be known to Entity
    // API. So check for that before doing any actual processing. If it's not
    // known yet, rebuild the property info cache and re-instantiate the
    // wrapper with all the latest property definitions.
    try {
      $entity->getPropertyInfo('cer');
    }
    catch (EntityMetadataWrapperException $e) {
      entity_property_info_cache_clear();
      $entity = new EntityDrupalWrapper($entity->type(), $entity->value());
    }

    $finder = new CerPresetFinder($entity);

    foreach ($finder->execute() as $preset) {
      $handler = new CerPresetHandler($preset, $entity);
      $handler->$op();
    }

    if ($context) {
      if (! isset($context['results']['count'])) {
        $context['results']['count'] = 0;
      }
      $context['results']['count']++;
    }
  }
  elseif ($entity_type) {
    if (is_numeric($entity)) {
      $entity = entity_object_load($entity, $entity_type);
    }

    if (is_object($entity) && empty($entity->cer_processed)) {
      cer_processing_entity($op, new EntityDrupalWrapper($entity_type, $entity), NULL, $context);
    }
  }
}

/**
 * Batch 'finished' callback.
 */
function cer_batch_update_existing_finished($success, $results, $operations) {
  if ($success) {
    $message = format_plural($results['count'], '1 entity processed.', '@count entities processed.');

    if (isset($results['errors'])) {
      $type = 'warning';
      foreach ($results['errors'] as $e) {
        drupal_set_message($e->getMessage(), 'error');
      }
    }
    else {
      $type = 'status';
    }
    drupal_set_message($message, $type);
  }
  else {
    // An error occurred. $operations contains the operations that remained unprocessed.
    $error_operation = reset($operations);
    $message = 'An error occurred while processing ' . $error_operation[0] . ' with arguments:' . print_r($error_operation[0], TRUE);
    drupal_set_message($message, 'error');
  }
}

/**
 * Implements hook_hook_info().
 *
 * @see cer.api.php for info about what these hooks do.
 */
function cer_hook_info() {
  return array(
    'cer_fields' => array(
      'group' => 'cer',
    ),
    'cer_fields_alter' => array(
      'group' => 'cer',
    ),
    // This is not used except when rebuilding legacy presets. It's here to
    // ensure that MODULE.cer.inc is auto-loaded when loading legacy presets
    // from code. (@see cer_update_7005())
    'cer_default_presets' => array(
      'group' => 'cer',
    ),
  );
}

/**
 * Returns options for the cer_weight field.
 */
function cer_weight_options() {
  $options = array();

  for ($i = -50; $i <= 50; $i++) {
    $options[$i] = $i;
  }

  return $options;
}

/**
 * Implements hook_features_ignore().
 */
function cer_features_ignore($component) {
  $ignores = array();
  if ($component == 'cer') {
    $ignores['wrapper'] = 0;
  }
  return $ignores;
}

/**
 * Implements hook_features_override_ignore().
 */
function cer_features_override_ignore($component) {
  return cer_features_ignore($component);
}

/**
 * Implements hook_entity_property_info().
 */
function cer_entity_property_info() {
  $properties = array();

  foreach (entity_get_info() as $entity_type => $entity_info) {
    // Expose a 'cer' struct on every entity type so that we can get special
    // entity-specific information during processing. This stuff is wrapped in
    // a struct to avoid namespace collisions, which can be disastrous.
    //
    // @see Issue #2223467
    //
    $properties[$entity_type]['properties']['cer'] = array(
      'label' => t('CER'),
      'description' => t('Information about the entity, used internally by CER.'),
      'type' => 'struct',
      'getter callback' => 'cer_get_cer_struct',
      'computed' => TRUE,
      'property info' => array(
        // lineage is a chain string, in the format used by {cer}.a and {cer}.b.
        // e.g., node:article:field_related_pages.
        'lineage' => array(
          'label' => t('Context'),
          'description' => t("The entity's lineage, represented as a string."),
          'type' => 'text',
          'getter callback' => 'cer_get_entity_lineage',
          'computed' => TRUE,
        ),
        // The depth of the entity. The default callback will just return 1, since most
        // entities don't live inside other entities (field collections are the main
        // exception).
        'depth' => array(
          'label' => t('Depth'),
          'description' => t("How deeply the entity is embedded."),
          'type' => 'integer',
          'getter callback' => 'cer_get_entity_depth',
          'computed' => TRUE,
        ),
        // The default callback returns the original entity because, as with the depth
        // property, most entities don't live inside other entities.
        'owner' => array(
          'label' => t('Owner'),
          'description' => t('The top-level entity under which this one is embedded.'),
          'type' => 'entity',
          'getter callback' => 'cer_get_entity_owner',
          'computed' => TRUE,
        ),
        // A wrapper around $entity->original that returns the current entity if there is
        // no original version available (i.e., during bulk update).
        'original' => array(
          'label' => t('Original'),
          'description' => t('The original entity (before update), or the current entity if an update has not occurred.'),
          'type' => 'entity',
          'getter callback' => 'cer_get_entity_original',
          'computed' => TRUE,
        ),
      ),
    );
  }

  return $properties;
}

/**
 * Implements hook_entity_property_info_alter().
 */
function cer_entity_property_info_alter(array &$info) {
  // Add a 'chain' property to the cer_left and cer_right fields so we can
  // easily get the field's value represented as a CerFieldChain.
  $info['cer']['bundles']['cer']['properties']['cer_left']['property info'] =
  $info['cer']['bundles']['cer']['properties']['cer_right']['property info'] = array(
    'chain' => array(
      'label' => t('Chain'),
      'description' => t('A CER field chain to the field instance.'),
      'type' => 'struct',
      'getter callback' => 'cer_unpack_field_chain',
      'computed' => TRUE,
    ),
  );

  // Field collections are special. Because they live inside other entities (to
  // potentially infinite levels of recursion), their CER property callbacks must be 
  // able to recurse upwards through the chain of embedding.
  if (module_exists('field_collection')) {
    $struct = &$info['field_collection_item']['properties']['cer']['property info'];

    $struct['lineage']['getter callback'] = 'cer_get_field_collection_lineage';
    $struct['lineage']['raw getter callback'] = 'cer_get_field_collection_lineage_array';
    $struct['depth']['getter callback'] = 'cer_get_field_collection_depth';
    $struct['owner']['getter callback'] = 'cer_get_field_collection_owner';
  }
}

// Include property callback functions
module_load_include('inc', 'cer', 'cer.properties');

if (module_exists('field_collection')) {
  module_load_include('inc', 'cer', 'cer.properties.field_collection');
}