<?php

/**
 * @file
 * Defines a field storage backend.
 */


/**
 * Implements hook_field_storage_info().
 */
function field_test_field_storage_info() {
  return array(
    'field_test_storage' => array(
      'label' => t('Test storage'),
      'description' => t('Dummy test storage backend. Stores field values in the variable table.'),
    ),
    'field_test_storage_failure' => array(
      'label' => t('Test storage failure'),
      'description' => t('Dummy test storage backend. Always fails to create fields.'),
    ),
  );
}

/**
 * Implements hook_field_storage_details().
 */
function field_test_field_storage_details($field) {
  $details = array();

  // Add field columns.
  $columns = array();
  foreach ((array) $field['columns'] as $column_name => $attributes) {
    $columns[$column_name] = $column_name;
  }
  return array(
    'drupal_variables' => array(
      'field_test_storage_data[FIELD_LOAD_CURRENT]' => $columns,
      'field_test_storage_data[FIELD_LOAD_REVISION]' => $columns,
    ),
  );
}

/**
 * Implements hook_field_storage_details_alter().
 *
 * @see FieldAttachStorageTestCase::testFieldStorageDetailsAlter()
 */
function field_test_field_storage_details_alter(&$details, $field) {

  // For testing, storage details are changed only because of the field name.
  if ($field['field_name'] == 'field_test_change_my_details') {
    $columns = array();
    foreach ((array) $field['columns'] as $column_name => $attributes) {
      $columns[$column_name] = $column_name;
    }
    $details['drupal_variables'] = array(
      FIELD_LOAD_CURRENT => array(
        'moon' => $columns,
      ),
      FIELD_LOAD_REVISION => array(
        'mars' => $columns,
      ),
    );
  }
}

/**
 * Helper function: stores or retrieves data from the 'storage backend'.
 */
function _field_test_storage_data($data = NULL) {
  if (!isset($data)) {
    return variable_get('field_test_storage_data', array());
  }
  else {
    variable_set('field_test_storage_data', $data);
  }
}

/**
 * Implements hook_field_storage_load().
 */
function field_test_field_storage_load($entity_type, $entities, $age, $fields, $options) {
  $data = _field_test_storage_data();

  $load_current = $age == FIELD_LOAD_CURRENT;

  foreach ($fields as $field_id => $ids) {
    $field = field_info_field_by_id($field_id);
    $field_name = $field['field_name'];
    $field_data = $data[$field['id']];
    $sub_table = $load_current ? 'current' : 'revisions';
    $delta_count = array();
    foreach ($field_data[$sub_table] as $row) {
      if ($row->type == $entity_type && (!$row->deleted || $options['deleted'])) {
        if (($load_current && in_array($row->entity_id, $ids)) || (!$load_current && in_array($row->revision_id, $ids))) {
          if (in_array($row->language, field_available_languages($entity_type, $field))) {
            if (!isset($delta_count[$row->entity_id][$row->language])) {
              $delta_count[$row->entity_id][$row->language] = 0;
            }
            if ($field['cardinality'] == FIELD_CARDINALITY_UNLIMITED || $delta_count[$row->entity_id][$row->language] < $field['cardinality']) {
              $item = array();
              foreach ($field['columns'] as $column => $attributes) {
                $item[$column] = $row->{$column};
              }
              $entities[$row->entity_id]->{$field_name}[$row->language][] = $item;
              $delta_count[$row->entity_id][$row->language]++;
            }
          }
        }
      }
    }
  }
}

/**
 * Implements hook_field_storage_write().
 */
function field_test_field_storage_write($entity_type, $entity, $op, $fields) {
  $data = _field_test_storage_data();

  list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);

  foreach ($fields as $field_id) {
    $field = field_info_field_by_id($field_id);
    $field_name = $field['field_name'];
    $field_data = &$data[$field_id];

    $all_languages = field_available_languages($entity_type, $field);
    $field_languages = array_intersect($all_languages, array_keys((array) $entity->$field_name));

    // Delete and insert, rather than update, in case a value was added.
    if ($op == FIELD_STORAGE_UPDATE) {
      // Delete languages present in the incoming $entity->$field_name.
      // Delete all languages if $entity->$field_name is empty.
      $languages = !empty($entity->$field_name) ? $field_languages : $all_languages;
      if ($languages) {
        foreach ($field_data['current'] as $key => $row) {
          if ($row->type == $entity_type && $row->entity_id == $id && in_array($row->language, $languages)) {
            unset($field_data['current'][$key]);
          }
        }
        if (isset($vid)) {
          foreach ($field_data['revisions'] as $key => $row) {
            if ($row->type == $entity_type && $row->revision_id == $vid) {
              unset($field_data['revisions'][$key]);
            }
          }
        }
      }
    }

    foreach ($field_languages as $langcode) {
      $items = (array) $entity->{$field_name}[$langcode];
      $delta_count = 0;
      foreach ($items as $delta => $item) {
        $row = (object) array(
          'field_id' => $field_id,
          'type' => $entity_type,
          'entity_id' => $id,
          'revision_id' => $vid,
          'bundle' => $bundle,
          'delta' => $delta,
          'deleted' => FALSE,
          'language' => $langcode,
        );
        foreach ($field['columns'] as $column => $attributes) {
          $row->{$column} = isset($item[$column]) ? $item[$column] : NULL;
        }

        $field_data['current'][] = $row;
        if (isset($vid)) {
          $field_data['revisions'][] = $row;
        }

        if ($field['cardinality'] != FIELD_CARDINALITY_UNLIMITED && ++$delta_count == $field['cardinality']) {
          break;
        }
      }
    }
  }

  _field_test_storage_data($data);
}

/**
 * Implements hook_field_storage_delete().
 */
function field_test_field_storage_delete($entity_type, $entity, $fields) {
  list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);

  // Note: reusing field_test_storage_purge(), like field_sql_storage.module
  // does, is highly inefficient in our case...
  foreach (field_info_instances($bundle) as $instance) {
    if (isset($fields[$instance['field_id']])) {
      $field = field_info_field_by_id($instance['field_id']);
      field_test_field_storage_purge($entity_type, $entity, $field, $instance);
    }
  }
}

/**
 * Implements hook_field_storage_purge().
 */
function field_test_field_storage_purge($entity_type, $entity, $field, $instance) {
  $data = _field_test_storage_data();

  list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);

  $field_data = &$data[$field['id']];
  foreach (array('current', 'revisions') as $sub_table) {
    foreach ($field_data[$sub_table] as $key => $row) {
      if ($row->type == $entity_type && $row->entity_id == $id) {
        unset($field_data[$sub_table][$key]);
      }
    }
  }

  _field_test_storage_data($data);
}

/**
 * Implements hook_field_storage_delete_revision().
 */
function field_test_field_storage_delete_revision($entity_type, $entity, $fields) {
  $data = _field_test_storage_data();

  list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);
  foreach ($fields as $field_id) {
    $field_data = &$data[$field_id];
    foreach (array('current', 'revisions') as $sub_table) {
      foreach ($field_data[$sub_table] as $key => $row) {
        if ($row->type == $entity_type && $row->entity_id == $id && $row->revision_id == $vid) {
          unset($field_data[$sub_table][$key]);
        }
      }
    }
  }

  _field_test_storage_data($data);
}

/**
 * Sort helper for field_test_field_storage_query().
 *
 * Sorts by entity type and entity id.
 */
function _field_test_field_storage_query_sort_helper($a, $b) {
  if ($a->type == $b->type) {
    if ($a->entity_id == $b->entity_id) {
      return 0;
    }
    else {
      return $a->entity_id < $b->entity_id ? -1 : 1;
    }
  }
  else {
    return $a->type < $b->type ? -1 : 1;
  }
}

/**
 * Implements hook_field_storage_create_field().
 */
function field_test_field_storage_create_field($field) {
  if ($field['storage']['type'] == 'field_test_storage_failure') {
    throw new Exception('field_test_storage_failure engine always fails to create fields');
  }

  $data = _field_test_storage_data();

  $data[$field['id']] = array(
    'current' => array(),
    'revisions' => array(),
  );

  _field_test_storage_data($data);
}

/**
 * Implements hook_field_storage_delete_field().
 */
function field_test_field_storage_delete_field($field) {
  $data = _field_test_storage_data();

  $field_data = &$data[$field['id']];
  foreach (array('current', 'revisions') as $sub_table) {
    foreach ($field_data[$sub_table] as &$row) {
      $row->deleted = TRUE;
    }
  }

  _field_test_storage_data($data);
}

/**
 * Implements hook_field_storage_delete_instance().
 */
function field_test_field_storage_delete_instance($instance) {
  $data = _field_test_storage_data();

  $field = field_info_field($instance['field_name']);
  $field_data = &$data[$field['id']];
  foreach (array('current', 'revisions') as $sub_table) {
    foreach ($field_data[$sub_table] as &$row) {
      if ($row->bundle == $instance['bundle']) {
        $row->deleted = TRUE;
      }
    }
  }

  _field_test_storage_data($data);
}

/**
 * Implements hook_field_attach_create_bundle().
 */
function field_test_field_attach_create_bundle($bundle) {
  // We don't need to do anything here.
}

/**
 * Implements hook_field_attach_rename_bundle().
 */
function field_test_field_attach_rename_bundle($bundle_old, $bundle_new) {
  $data = _field_test_storage_data();

  // We need to account for deleted or inactive fields and instances.
  $instances = field_read_instances(array('bundle' => $bundle_new), array('include_deleted' => TRUE, 'include_inactive' => TRUE));
  foreach ($instances as $field_name => $instance) {
    $field = field_info_field_by_id($instance['field_id']);
    if ($field['storage']['type'] == 'field_test_storage') {
      $field_data = &$data[$field['id']];
      foreach (array('current', 'revisions') as $sub_table) {
        foreach ($field_data[$sub_table] as &$row) {
          if ($row->bundle == $bundle_old) {
            $row->bundle = $bundle_new;
          }
        }
      }
    }
  }

  _field_test_storage_data($data);
}

/**
 * Implements hook_field_attach_delete_bundle().
 */
function field_test_field_attach_delete_bundle($entity_type, $bundle, $instances) {
  $data = _field_test_storage_data();

  foreach ($instances as $instance) {
    $field = field_info_field_by_id($instance['field_id']);
    if ($field['storage']['type'] == 'field_test_storage') {
      $field_data = &$data[$field['id']];
      foreach (array('current', 'revisions') as $sub_table) {
        foreach ($field_data[$sub_table] as &$row) {
          if ($row->bundle == $bundle) {
            $row->deleted = TRUE;
          }
        }
      }
    }
  }

  _field_test_storage_data($data);
}