<?php

/**
 * @file
 * Install, update, and uninstall functions for the metatag module.
 */

/**
 * Implements hook_schema().
 */
function metatag_schema() {
  $schema['metatag_config'] = array(
    'description' => 'Storage of meta tag configuration and defaults.',
    'export' => array(
      'key' => 'instance',
      'key name' => 'Instance',
      'primary key' => 'cid',
      'identifier' => 'config',
      'default hook' => 'metatag_config_default',
      'api' => array(
        'owner' => 'metatag',
        'api' => 'metatag',
        'minimum_version' => 1,
        'current_version' => 1,
      ),
      'cache defaults' => TRUE,
      'default cache bin' => 'cache_metatag',
    ),
    'fields' => array(
      'cid' => array(
        'type' => 'serial',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'description' => 'The primary identifier for a metatag configuration set.',
        'no export' => TRUE,
      ),
      'instance' => array(
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
        'description' => 'The machine-name of the configuration, typically entity-type:bundle.',
      ),
      'config' => array(
        'type' => 'blob',
        'size' => 'big',
        'not null' => TRUE,
        'serialize' => TRUE,
        'description' => 'Serialized data containing the meta tag configuration.',
        'translatable' => TRUE,
      ),
    ),
    'primary key' => array('cid'),
    'unique keys' => array(
      'instance' => array('instance'),
    ),
  );

  $schema['metatag'] = array(
    'fields' => array(
      'entity_type' => array(
        'type' => 'varchar',
        'length' => 32,
        'not null' => TRUE,
        'default' => '',
        'description' => 'The entity type this data is attached to',
      ),
      'entity_id' => array(
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
        'description' => 'The entity id this data is attached to',
      ),
      // @todo Enable revisionable meta tags.
      'data' => array(
        'type' => 'blob',
        'size' => 'big',
        'not null' => TRUE,
        'serialize' => TRUE,
      ),
      'language' => array(
        'type' => 'varchar',
        'length' => 32,
        'not null' => TRUE,
        'default' => '',
        'description' => 'The language of the tag.',
      ),
    ),
    'primary key' => array('entity_type', 'entity_id', 'language'),
  );

  $schema['cache_metatag'] = drupal_get_schema_unprocessed('system', 'cache');
  $schema['cache_metatag']['description'] = t('Cache table for the generated meta tag output.');

  return $schema;
}

/**
 * Implements hook_requirements().
 */
function metatag_requirements($phase) {
  $requirements = array();
  // Ensure translations don't break during installation.
  $t = get_t();

  if ($phase == 'runtime') {
    // Work out the release of D7 that is currently running.
    list($major, $minor) = explode('.', VERSION);
    // Strip off any suffixes on the version string, e.g. "17-dev".
    if (strpos('-', $minor)) {
      list($minor, $suffix) = explode('-', $minor);
    }

    // Releases of Drupal older than 7.15 did not have entity_language(), which
    // is now required.
    if ($minor < 15) {
      $requirements['metatag'] = array(
        'severity' => REQUIREMENT_WARNING,
        'title' => 'Metatag',
        'value' => $t('Upgrade Drupal core to v7.15 or newer'),
        'description' => $t("This older version of Drupal core is missing functionality necessary for the module's multilingual support, it must be upgraded to at least version 7.15."),
      );
    }
    // Releases of Drupal older than 7.17 did not trigger hook_entity_view on
    // term pages, so recommend updating.
    elseif ($minor < 17) {
      $requirements['metatag'] = array(
        'severity' => REQUIREMENT_WARNING,
        'title' => 'Metatag',
        'value' => $t('Upgrade Drupal core to v7.17 or newer'),
        'description' => $t('Your older version of Drupal core is missing functionality necessary for taxonomy term pages to work correctly, it is strongly recommended to upgrade to the latest release.'),
      );
    }
    // Everything's OK.
    else {
      $requirements['metatag'] = array(
        'severity' => REQUIREMENT_OK,
        'title' => 'Metatag',
        'value' => $t('Drupal core is compatible'),
        'description' => $t('Older versions of Drupal core were missing functionality necessary for taxonomy term pages to work correctly, but this version <em>will</em> work correctly.'),
      );
    }

    // Add a note if Page Title is also installed.
    if (module_exists('page_title')) {
      $requirements['metatag_page_title'] = array(
        'severity' => REQUIREMENT_INFO,
        'title' => 'Metatag',
        'value' => $t('Possible conflicts with Page Title module'),
        'description' => $t('The Metatag module is able to customize page titles so running the Page Title module simultaneously can lead to complications.'),
      );
    }

    // Add a note if Page Title is also installed.
    if (module_exists('exclude_node_title')) {
      $requirements['metatag_exclude_node_title'] = array(
        'severity' => REQUIREMENT_INFO,
        'title' => 'Metatag',
        'value' => $t('Possible conflicts with Exclude Node Title module'),
        'description' => $t('The Metatag module\'s default settings for content types (nodes) uses [node:title] for the page title. Unfortunately, Exclude Node Title hides this so the page title ends up blank. It is recommended to <a href="!config">change the "title" field\'s default value</a> to "[current-page:title]" instead of "[node:title]" for any content types affected by Exclude Node Title.', array('!config' => 'admin/config/search/metatags')),
      );
    }

    // Add a note if the deprecated metatag.entity_translation.inc file still
    // exists.
    $filename = 'metatag.entity_translation.inc';
    if (file_exists(dirname(__FILE__) . '/' . $filename)) {
      $requirements['metatag_deprecated_et_file'] = array(
        'severity' => REQUIREMENT_ERROR,
        'title' => 'Metatag',
        'value' => $t('Unwanted :filename file found', array(':filename' => $filename)),
        'description' => $t("The :filename file was removed in v7.x-1.0-beta5 but it still exists in the site's Metatag module's directory and will cause problems. This file needs to be removed. The file's path in the Drupal directory structure is:<br /><code>!short_path</code><br />The file's full path is:<br /><code>!full_path</code>", array(':filename' => $filename, '!short_path' => drupal_get_path('module', 'metatag') . '/' . $filename, '!full_path' => dirname(__FILE__) . $filename)),
      );
    }
  }

  return $requirements;
}

/**
 * Implements hook_install().
 */
// function metatag_install() {
// }

/**
 * Implements hook_uninstall().
 */
function metatag_uninstall() {
  // This variable is created via hook_enable.
  variable_del('metatag_schema_installed');
}

/**
 * Implements hook_enable().
 */
function metatag_enable() {
  variable_set('metatag_schema_installed', TRUE);
}

/**
 * Implements hook_disable().
 */
// function metatag_disable() {
// }

/**
 * Disable the deprecated metatag_ui module which has been merged into metatag.
 */
function metatag_update_7000() {
  if (module_exists('metatag_ui')) {
    module_disable(array('metatag_ui'), FALSE);
    drupal_uninstall_modules(array('metatag_ui'), FALSE);
  }
}

/**
 * Fix the "{metatag_config}.cid column cannot be NULL" error.
 */
function metatag_update_7001() {
  $table_name = 'metatag_config';
  $field_name = 'cid';
  $field_spec = array(
    'type' => 'serial',
    'unsigned' => TRUE,
    'not null' => TRUE,
    'description' => 'The primary identifier for a metatag configuration set.',
  );
  $keys = array('primary key' => array($field_name));

  // Before making any changes, drop the existing primary key.
  try {
    db_drop_primary_key($table_name);
  }
  catch (Exception $e) {
    drupal_set_message('Caught an exception: ', $e->getMessage());
  }

  // Rejig the field, and turn on the primary key again.
  db_change_field($table_name, $field_name, $field_name, $field_spec, $keys);
}

/**
 * Disable the deprecated metatag_ui module which has been merged into metatag,
 * again.
 */
function metatag_update_7002() {
  if (module_exists('metatag_ui')) {
    module_disable(array('metatag_ui'), FALSE);
    drupal_uninstall_modules(array('metatag_ui'), FALSE);
    drupal_set_message(t('The deprecated Metatag UI module has been disabled.'));
  }
}

/**
 * Add the {metatag}.language field.
 */
function metatag_update_7003() {
  // Set the target table and field name.
  $table_name = 'metatag';
  $field_name = 'language';

  // Don't add the new field if it already exists.
  if (!db_field_exists($table_name, $field_name)) {
    // Describe the new field.
    $field_spec = array(
      'type' => 'varchar',
      'length' => 32,
      'not null' => TRUE,
      'default' => '',
      'description' => 'The language of the tag',
    );

    // Add it and update the primary key.
    db_add_field($table_name, $field_name, $field_spec);
    db_drop_primary_key($table_name);
    db_add_primary_key($table_name, array('entity_type', 'entity_id', 'language'));
  }
}

/**
 * Replaced by updates 7009, 7010, 7011, 7012 and 7013.
 */
function metatag_update_7004() {
  // Do nothing.
}

/**
 * Removing wrong metatag watchdog entries that break the admin/reports/dblog
 * page.
 */
function metatag_update_7005() {
  if (db_table_exists('watchdog')) {
    db_delete('watchdog')
      ->condition('type', 'metatag')
      ->condition('variables', serialize('info'))
      ->execute();
  }
}

/**
 * Remove {metatag} records that were added by old versions of the module for
 * entities that don't actually support Metatag. A more complete version of
 * this will be added later on after it's (hopefully) guaranteed that all
 * modules have updated to the correct API usage.
 */
function metatag_update_7006() {
  $entity_types = array(
    // Core.
    'comment',
    'menu_link',
    'taxonomy_vocabulary',
    // Some contrib entities.
    'mailchimp_list',
    'profile2',
    'profile2_type',
    'redirect',
    'rules_config',
    'wysiwyg_profile',
  );
  foreach ($entity_types as $entity_type) {
    $num_deleted = db_delete('metatag')
      ->condition('entity_type', $entity_type)
      ->execute();
    if ($num_deleted > 0) {
      drupal_set_message(t('Removed @count meta tag record(s) for the @type entity type, it does not support meta tags.', array('@count' => $num_deleted, '@type' => $entity_type)));
    }
  }
}

/**
 * Remove {metatag} records for objects that have been deleted; older versions
 * of Metatag may have failed to purge these.
 */
function metatag_update_7007() {
  $nodes = db_query("SELECT m.entity_id
    FROM {metatag} m
    LEFT OUTER JOIN {node} n
      ON m.entity_id=n.nid
    WHERE m.entity_type='node'
      AND n.nid IS NULL")
    ->fetchCol();
  if (count($nodes) > 0) {
    $deleted = db_delete('metatag')
      ->condition('entity_type', 'node')
      ->condition('entity_id', $nodes)
      ->execute();
    if ($deleted > 0) {
      drupal_set_message(t('Removed @count meta tag record(s) for nodes that had been purged.', array('@count' => $deleted)));
    }
    else {
      drupal_set_message(t('There were no meta tag records to purge for removed nodes. This is a good thing :)'));
    }
  }

  $users = db_query("SELECT m.entity_id
    FROM {metatag} m
    LEFT OUTER JOIN {users} u
      ON m.entity_id=u.uid
    WHERE m.entity_type='user'
      AND u.uid IS NULL")
    ->fetchCol();
  if (count($users) > 0) {
    $deleted = db_delete('metatag')
      ->condition('entity_type', 'user')
      ->condition('entity_id', $users)
      ->execute();
    if ($deleted > 0) {
      drupal_set_message(t('Removed @count meta tag record(s) for users that had been purged.', array('@count' => $deleted)));
    }
    else {
      drupal_set_message(t('There were no meta tag records to purge for removed users. This is a good thing :)'));
    }
  }

  // Only run this if the Taxonomy module is enabled.
  if (module_exists('taxonomy')) {
    $terms = db_query("SELECT m.entity_id
      FROM {metatag} m
      LEFT OUTER JOIN {taxonomy_term_data} t
        ON m.entity_id=t.tid
      WHERE m.entity_type='taxonomy_term'
        AND t.tid IS NULL")
      ->fetchCol();
    if (count($terms) > 0) {
      $deleted = db_delete('metatag')
        ->condition('entity_type', 'taxonomy_term')
        ->condition('entity_id', $terms)
        ->execute();
      if ($deleted > 0) {
        drupal_set_message(t('Removed @count meta tag record(s) for taxonomy terms that had been purged.', array('@count' => $deleted)));
      }
      else {
        drupal_set_message(t('There were no meta tag records to purge for removed taxonomy terms. This is a good thing :)'));
      }
    }
  }
}

/**
 * Remove any empty records that may be hanging around from old releases.
 */
function metatag_update_7008() {
  $conditions = db_or()
    ->isNull('data')
    ->condition('data', '')
    ->condition('data', serialize(array()));
  $deleted = db_delete("metatag")
    ->condition($conditions)
    ->execute();
  if ($deleted > 0) {
    drupal_set_message(t('Purged @count empty meta tag record(s).', array('@count' => $deleted)));
  }
}

/**
 * Fix {metatag} records for taxonomy terms.
 */
function metatag_update_7009() {
  if (module_exists('taxonomy')) {
    // Remove duplicates.
    _metatag_remove_dupes('taxonomy_term');
  }

  // The taxonomy term entity doesn't support a 'language' option, so reset it
  // to LANGUAGE_NONE.
  $result = db_query("UPDATE {metatag} SET language = :language WHERE entity_type='taxonomy_term'", array(':language' => LANGUAGE_NONE));
  if ($result->rowCount() > 0) {
    drupal_set_message(t('Fixed language values for @count taxonomy terms.', array('@count' => $result->rowCount())));
  }
}

/**
 * Fix {metatag} records for users.
 */
function metatag_update_7010() {
  // Remove duplicates.
  _metatag_remove_dupes('user');

  // Update User values.
  $result = db_query("UPDATE {metatag} SET language = :language WHERE entity_type='user'", array(':language' => LANGUAGE_NONE));
  if ($result->rowCount() > 0) {
    drupal_set_message(t('Fixed language values for @count user records.', array('@count' => $result->rowCount())));
  }
}

/**
 * Fix {metatag} records for nodes.
 */
function metatag_update_7011(&$sandbox) {
  // Only proceed if Entity_Translation is not enabled as it allows each node
  // record to have multiple languages available.
  if (module_exists('entity_translation')) {
    drupal_set_message(t("Entity Translation is enabled, so node meta tags will not be updated, to avoid accidental dataloss."));
    return;
  }

  // Process records by groups of 10 (arbitrary value).
  // When a group is processed, the batch update engine determines whether it
  // should continue processing in the same request or provide progress
  // feedback to the user and wait for the next request.
  $limit = 20;

  // Use the sandbox at your convenience to store the information needed
  // to track progression between successive calls to the function.
  if (!isset($sandbox['progress'])) {
    // The count of records visited so far.
    $sandbox['progress'] = 0;

    // Remove duplicates.
    _metatag_remove_dupes('node');

    // Update Node values.
    $nodes = db_query("SELECT n.nid, n.language FROM {node} n INNER JOIN {metatag} m ON n.nid = m.entity_id WHERE m.entity_type = 'node' AND n.language != m.language ORDER BY nid");
    $sandbox['records'] = array();
    foreach ($nodes as $record) {
      $sandbox['records'][] = $record;
    }

    // If there's no data, don't bother with the extra work.
    if (empty($sandbox['records'])) {
      watchdog('metatag', 'Update 7011: No nodes need the Metatag language values fixed.', array(), WATCHDOG_INFO);
      if (drupal_is_cli()) {
        drupal_set_message(t('Update 7011: No nodes need the Metatag language values fixed.'));
      }
      return t('No nodes need the Metatag language values fixed.');
    }

    // Total records that must be visited.
    $sandbox['max'] = count($sandbox['records']);

    // A place to store messages during the run.
    $sandbox['messages'] = array();

    // An initial record of the number of records to be updated.
    watchdog('metatag', 'Update 7011: !count records to update.', array('!count' => $sandbox['max']), WATCHDOG_INFO);
    if (drupal_is_cli()) {
      drupal_set_message(t('Update 7011: !count records to update.', array('!count' => $sandbox['max'])));
    }

    // Last record processed.
    $sandbox['current_record'] = -1;

    // Because a lot of other processing happens on the first iteration, just do
    // one.
    $limit = 1;
  }

  // The for loop will run as normal when ran via update.php, but when ran via
  // Drush it'll just run 'til it's finished.
  $increment = 1;
  if (drupal_is_cli()) {
    $increment = 0;
  }

  // Set default values.
  for ($ctr = 0; $ctr < $limit; $ctr += $increment) {
    $sandbox['current_record']++;
    if (empty($sandbox['records'][$sandbox['current_record']])) {
      break;
    }

    // Shortcuts for later.
    $langcode = $sandbox['records'][$sandbox['current_record']]->language;
    $nid = $sandbox['records'][$sandbox['current_record']]->nid;

    db_update('metatag')
      ->fields(array('language' => $langcode))
      ->condition('entity_type', 'node')
      ->condition('entity_id', $nid)
      ->execute();

    // Update our progress information.
    $sandbox['progress']++;
  }

  // Set the "finished" status, to tell batch engine whether this function
  // needs to run again. If you set a float, this will indicate the progress of
  // the batch so the progress bar will update.
  $sandbox['#finished'] = ($sandbox['progress'] >= $sandbox['max']) ? TRUE : ($sandbox['progress'] / $sandbox['max']);

  if ($sandbox['#finished']) {
    // Clear all caches so the fixed data will be reloaded.
    cache_clear_all('*', 'cache_metatag', TRUE);

    // A final log of the number of records that were converted.
    watchdog('metatag', 'Update 7011: !count records were updated in total.', array('!count' => $sandbox['progress']), WATCHDOG_INFO);
    if (drupal_is_cli()) {
      drupal_set_message(t('Update 7011: !count records were updated.', array('!count' => $sandbox['progress'])));
    }

    // hook_update_N() may optionally return a string which will be displayed
    // to the user.
    return t('Fixed the Metatag language values for @count nodes.', array('!count' => $sandbox['progress']));
  }
}

/**
 * Remove duplicate {metatag} records for non-core entities.
 */
function metatag_update_7012() {
  if (module_exists('entity_translation')) {
    drupal_set_message(t("Entity Translation is enabled, duplicate meta tags will not be removed for custom entities, to avoid accidental dataloss."));
    return;
  }

  $records = db_select('metatag', 'm')
    ->fields('m', array('entity_type'))
    ->condition('m.entity_type', array('node', 'taxonomy_term', 'user'), 'NOT IN')
    ->orderBy('m.entity_type', 'ASC')
    ->orderBy('m.entity_id', 'ASC')
    ->distinct()
    ->execute();

  $entity_types = array();
  foreach ($records as $record) {
    $entity_types[] = $record->entity_type;
    // Remove duplicates.
    _metatag_remove_dupes($record->entity_type);
  }

  if (empty($entity_types)) {
    drupal_set_message(t('There were no other records to fix.'));
  }
}

/**
 * Fix the {metatag} language value for all non-core entity records. This might
 * take a while, depending on how much data needs to be converted.
 */
function metatag_update_7013(&$sandbox) {
  if (module_exists('entity_translation')) {
    drupal_set_message(t("Entity Translation is enabled, meta tags will not be updated for custom entities, to avoid accidental dataloss."));
    return;
  }

  // Use the sandbox at your convenience to store the information needed
  // to track progression between successive calls to the function.
  if (!isset($sandbox['progress'])) {
    // The count of records visited so far.
    $sandbox['progress'] = 0;

    // Because the {metatag} table uses multiple primary keys, there's no easy
    // way to do this, so we're going to cache all record keys and manually
    // step through them.
    $records = db_select('metatag', 'm')
      ->fields('m', array('entity_type', 'entity_id'))
      ->condition('m.entity_type', array('node', 'taxonomy_term', 'user'), 'NOT IN')
      ->orderBy('m.entity_type', 'ASC')
      ->orderBy('m.entity_id', 'ASC')
      ->execute();
    $sandbox['records'] = array();
    foreach ($records as $record) {
      $sandbox['records'][] = $record;
    }

    // If there's no data, don't bother with the extra work.
    if (empty($sandbox['records'])) {
      watchdog('metatag', 'Update 7013: No meta tag records need updating.', array(), WATCHDOG_INFO);
      if (drupal_is_cli()) {
        drupal_set_message(t('Update 7013: No meta tag records need updating.'));
      }
      return t('No meta tag records need updating.');
    }

    // Total records that must be visited.
    $sandbox['max'] = count($sandbox['records']);

    // A place to store messages during the run.
    $sandbox['messages'] = array();

    // An initial record of the number of records to be updated.
    watchdog('metatag', 'Update 7013: !count records to update.', array('!count' => $sandbox['max']), WATCHDOG_INFO);
    if (drupal_is_cli()) {
      drupal_set_message(t('Update 7013: !count records to update.', array('!count' => $sandbox['max'])));
    }

    // Last record processed.
    $sandbox['current_record'] = -1;
  }

  // Process records by groups of 10 (arbitrary value).
  // When a group is processed, the batch update engine determines whether it
  // should continue processing in the same request or provide progress
  // feedback to the user and wait for the next request.
  $limit = 10;

  // The for loop will run as normal when ran via update.php, but when ran via
  // Drush it'll just run 'til it's finished.
  $increment = 1;
  if (drupal_is_cli()) {
    $increment = 0;
  }

  // Set default values.
  for ($ctr = 0; $ctr < $limit; $ctr += $increment) {
    $sandbox['current_record']++;
    if (empty($sandbox['records'][$sandbox['current_record']])) {
      break;
    }

    // Shortcuts for later.
    $entity_type = $sandbox['records'][$sandbox['current_record']]->entity_type;
    $entity_id = $sandbox['records'][$sandbox['current_record']]->entity_id;

    // Load the entity.
    $entities = entity_load($entity_type, array($entity_id));
    if (!empty($entities)) {
      $entity = array_pop($entities);

      // Make sure that the entity has a language set.
      if (!empty($entity)) {
        // If there's a (non-empty) language value, use it.
        $new_language = entity_language($entity_type, $entity);
        if (empty($new_language)) {
          $new_language = LANGUAGE_NONE;
        }
        // Update the 'language' value.
        db_update('metatag')
          ->fields(array('language' => $new_language))
          ->condition('entity_type', $entity_type)
          ->condition('entity_id', $entity_id)
          ->execute();
      }
    }

    // Update our progress information.
    $sandbox['progress']++;
  }

  // Set the "finished" status, to tell batch engine whether this function
  // needs to run again. If you set a float, this will indicate the progress of
  // the batch so the progress bar will update.
  $sandbox['#finished'] = ($sandbox['progress'] >= $sandbox['max']) ? TRUE : ($sandbox['progress'] / $sandbox['max']);

  if ($sandbox['#finished']) {
    // Clear all caches so the fixed data will be reloaded.
    cache_clear_all('*', 'cache_metatag', TRUE);

    // A final log of the number of records that were converted.
    watchdog('metatag', 'Update 7013: !count records were updated in total.', array('!count' => $sandbox['progress']), WATCHDOG_INFO);
    if (drupal_is_cli()) {
      drupal_set_message(t('Update 7013: !count records were updated.', array('!count' => $sandbox['progress'])));
    }

    // hook_update_N() may optionally return a string which will be displayed
    // to the user.
    return t('!count records were updated in total.', array('!count' => $sandbox['progress']));
  }
}

/**
 * Remove duplicate records for a given entity.
 *
 * It should be OK to run this without doing a separate batch process as there
 * shouldn't be many records that have this problem. Hopefully.
 *
 * @param $entity_type
 *   The name of an entity type to check for.
 */
function _metatag_remove_dupes($entity_type) {
  $purge_count = 0;

  // First step: fix the records. There should not be multiple records for the
  // same entity_id with different languages.
  $dupe_records = db_query("SELECT m.entity_id, count(m.language) AS the_count
    FROM {metatag} m
    WHERE
      m.entity_type = :type
    GROUP BY m.entity_id
    HAVING count(m.language) > 1", array(':type' => $entity_type));

  if (!empty($dupe_records)) {
    foreach ($dupe_records as $record) {
      $entity_id = $record->entity_id;
      $langs = db_query("SELECT m.entity_id, m.language, m.data FROM {metatag} m WHERE m.entity_type = :type AND m.entity_id = :id", array(':type' => $entity_type, ':id' => $entity_id))->fetchAll();

      // Work out which language record to remove. Will need to store this as
      // an array incase there are multiple records to purge.
      $langs_to_remove = array();

      // Check for duplicate records.
      // Outer loop starts from the beginning.
      for ($outer = 0; $outer < count($langs); $outer++) {
        // This record may have been removed already.
        if (isset($langs[$outer])) {
          // Inner loop starts from the end.
          for ($inner = count($langs) - 1; $inner > 0; $inner--) {
            // Work out if the outer loop's data is the same as the inner
            // loop's.
            if (isset($langs[$inner]) && $langs[$outer]->data == $langs[$inner]->data) {
              // Remove the second record.
              $langs_to_remove[] = $langs[$inner]->language;
              unset($langs[$inner]);
            }
          }
        }
      }

      // Only one record left.
      if (count($langs) == 1) {
        // This is how it should be, this record is fine.
      }
      // More than one record, work out which one to keep.
      elseif (count($langs) > 1) {
        // Work out the entity's language.
        $entity = entity_load($entity_type, $entity_id);
        $entity_language = entity_language($entity_type, $entity);
        if (empty($language)) {
          $entity_language = LANGUAGE_NONE;
        }

        // Work out if the entity's language record exists.
        $lang_pos = NULL;
        foreach ($langs as $key => $record) {
          if ($record->language == $entity_language) {
            $lang_pos = $key;
            break;
          }
        }
        // If the language record exists, delete the others.
        if (isset($lang_pos)) {
          foreach ($langs as $key => $record) {
            if ($record->language != $entity_language) {
              $langs_to_remove[] = $record->language;
            }
          }
        }
        // Otherwise look for a record for the site's default language.
        else {
          foreach ($langs as $key => $record) {
            if ($record->language == $GLOBALS['language']->language) {
              $lang_pos = $key;
              break;
            }
          }
          if (isset($lang_pos)) {
            foreach ($langs as $key => $record) {
              if ($record->language != $GLOBALS['language']->language) {
                $langs_to_remove[] = $record->language;
              }
            }
          }
          // Finally check for LANGUAGE_NONE.
          else {
            foreach ($langs as $key => $record) {
              if ($record->language == LANGUAGE_NONE) {
                $lang_pos = $key;
                break;
              }
            }
            if (isset($lang_pos)) {
              foreach ($langs as $key => $record) {
                if ($record->language != LANGUAGE_NONE) {
                  $langs_to_remove[] = $record->language;
                }
              }
            }
          }
        }
      }

      // Purge the redundant records.
      if (!empty($langs_to_remove)) {
        $purge_count += db_delete('metatag')
          ->condition('entity_type', $entity_type)
          ->condition('entity_id', $entity_id)
          ->condition('language', $langs_to_remove)
          ->execute();
      }
    }
  }

  if (empty($purge_count)) {
    drupal_set_message(t('No duplicate :entity_type records were found (this is a good thing).', array(':entity_type' => $entity_type)));
    watchdog('metatag', 'No duplicate :entity_type records were found (this is a good thing).', array(':entity_type' => $entity_type));
  }
  else {
    drupal_set_message(t('Purged :count duplicate :entity_type record(s).', array(':count' => $purge_count, ':entity_type' => $entity_type)));
    watchdog('metatag', 'Purged :count duplicate :entity_type record(s).', array(':count' => $purge_count, ':entity_type' => $entity_type));
    return;
  }
}

/**
 * Fix {metatag} records that may have been corrupted by #1871020.
 */
function metatag_update_7014() {
  $records = db_query("SELECT *
  FROM {metatag} m
  WHERE
       m.data LIKE :nolang
    OR m.data LIKE :lang
    OR m.data LIKE :und",
    array(
      ':nolang' => 'a:1:{s:0:"";a:%:{s:%;a:%:{%;}}}',
      ':lang' => 'a:1:{s:2:"__";a:%:{s:%;a:%:{%;}}}',
      ':und' => 'a:1:{s:3:"___";a:%:{s:%;a:%:{%;}}}',
    ));

  // Nothing to fix.
  if ($records->rowCount() == 0) {
    drupal_set_message(t('No corrupt records to fix, this is good news :-)'));
  }

  // Fix the faulty records.
  else {
    foreach ($records as $record) {
      // Extract the data and get the first element of the array, this should be
      // valid data.
      $record->data = reset(unserialize($record->data));

      // Update the record.
      drupal_write_record('metatag', $record, array('entity_type', 'entity_id', 'language'));
    }
    drupal_set_message(t('Fixed @count corrupt meta tag record(s).', array('@count' => $records->rowCount())));
  }
}