<?php
// $Id$

/**
 * @file
 * Definition of FeedsDataProcessor.
 */

/**
 * Creates simple table records from feed items. Uses Data module.
 */
class FeedsDataProcessor extends FeedsProcessor {

  /**
   * Implementation of FeedsProcessor::process().
   */
  public function process(FeedsParserResult $parserResult, FeedsSource $source) {

    // Count number of created and updated nodes.
    $inserted  = $updated = 0;

    foreach ($parserResult->value['items'] as $item) {
      if (!($id = $this->existingItemId($item, $source)) || $this->config['update_existing']) {
        // Map item to a data record, feed_nid and timestamp are mandatory.
        $data = array();
        $data['feed_nid'] = $source->feed_nid;
        $data['timestamp'] = FEEDS_REQUEST_TIME;
        $data = $this->map($item, $data);

        // Save data.
        if ($id) {
          $data['id'] = $id;
          $this->handler()->update($data, 'id');
          $updated++;
        }
        else {
          $this->handler()->insert($data);
          $inserted++;
        }
      }
    }

    // Set messages.
    if ($inserted) {
      drupal_set_message(t('Created !number records in !table.', array('!number' => $inserted, '!table' => $this->tableName())));
    }
    elseif ($updated) {
      drupal_set_message(t('Updated !number records in !table.', array('!number' => $updated, '!table' => $this->tableName())));
    }
    else {
      drupal_set_message(t('There are no new records.'));
    }
  }

  /**
   * Implementation of FeedsProcessor::clear().
   *
   * Delete all data records for feed_nid in this table.
   */
  public function clear(FeedsSource $source) {
    $clause = array(
      'feed_nid' => $source->feed_nid,
    );
    $num = $this->handler()->delete($clause);
    drupal_set_message(t('Deleted !number records from !table.', array('!number' => $num, '!table' => $this->tableName())));
  }

  /**
   * Implement expire().
   */
  public function expire($time = NULL) {
    if ($time === NULL) {
      $time = $this->expiryTime();
    }
    if ($time == FEEDS_EXPIRE_NEVER) {
      return;
    }
    $clause = array(
      'timestamp' => array(
        '<',
        FEEDS_REQUEST_TIME - $time,
      ),
    );
    $num = $this->handler()->delete($clause);
    drupal_set_message(t('Expired !number records from !table.', array('!number' => $num, '!table' => $this->tableName())));
  }

  /**
   * Return expiry time.
   */
  public function expiryTime() {
    return $this->config['expire'];
  }

  /**
   * Override parent::addMapping() and create a new field for new mapping
   * targets.
   *
   * @see getMappingTargets().
   */
  public function addMapping($source, $target, $unique = FALSE) {
    if (empty($source) || empty($target)) {
      return;
    }

    // Create a new field with targets that start with "new:"
    @list($new, $type) = explode(':', $target);

    if ($new == 'new') {
      // Build a field name from the source key.
      $field_name = data_safe_name($source);
      // Get the full schema spec from data.
      $type = data_get_field_definition($type);
      // Add the field to the table.
      $schema = $this->table()->get('table_schema');
      if (!isset($schema['fields'][$field_name])) {
        $target = $this->table()->addField($field_name, $type);
        // Let the user know.
        drupal_set_message(t('Created new field "!name".', array('!name' => $field_name)));
      }
      else {
        throw new Exception(t('Field !field_name already exists as a mapping target. Remove it from mapping if you would like to map another source to it. Remove it from !data_table table if you would like to change its definition.', array('!field_name' => $field_name, '!data_table' => l($this->table()->get('name'), 'admin/content/data'))));
      }
    }

    // Let parent populate the mapping configuration.
    parent::addMapping($source, $target, $unique);
  }

  /**
   * Return available mapping targets.
   */
  public function getMappingTargets() {
    $schema = $this->table()->get('table_schema');
    $meta = $this->table()->get('meta');

    // Collect all existing fields except id and field_nid and offer them as
    // mapping targets.
    $existing_fields = $new_fields = array();
    if (isset($schema['fields'])) {
      foreach ($schema['fields'] as $field_name => $field) {
        if (!in_array($field_name, array('id', 'feed_nid'))) {
          // Any existing field can be optionally unique.
          $existing_fields[$field_name] = array(
            'name' => empty($meta['fields'][$field_name]['label']) ? $field_name : $meta['fields'][$field_name]['label'],
            'optional_unique' => TRUE,
          );
        }
      }
    }

    // Do the same for every joined table.
    foreach ($this->handler()->joined_tables as $table) {
      $schema = data_get_table($table)->get('table_schema');
      if (isset($schema['fields'])) {
        foreach ($schema['fields'] as $field_name => $field) {
          if (!in_array($field_name, array('id', 'feed_nid'))) {
            // Fields in joined tables can't be unique.
            $existing_fields["$table.$field_name"] = array(
              'name' => $table .'.'. (empty($meta['fields'][$field_name]['label']) ? $field_name : $meta['fields'][$field_name]['label']),
              'optional_unique' => FALSE,
            );
          }
        }
      }
    }

    // Now add data field types as mapping targets.
    $field_types = drupal_map_assoc(array_keys(data_get_field_definitions()));
    foreach ($field_types as $k => $v) {
      $new_fields['new:'. $k] = t('[new] !type', array('!type' => $v));
    }
    return $new_fields + $existing_fields;
  }

  /**
   * Set target element, bring element in a FeedsDataHandler format.
   */
  public function setTargetElement(&$target_item, $target_element, $value) {
    if (strpos($target_element, '.')) {

      /**

      Add field in FeedsDataHandler format.

      This is the tricky part, FeedsDataHandler expects an *array* of records
      at #[joined_table_name]. We need to iterate over the $value that has
      been mapped to this element and create a record array from each of
      them.
      */
      list($table, $field) = explode('.', $target_element);

      $values = array();
      $value = is_array($value) ? $value : array($value);
      foreach ($value as $v) {
        // Create a record array.
        $values[] = array(
          $field => $v,
        );
      }
      $target_item['#'. $table] = $values;
    }
    else {
      $target_item[$target_element] = $value;
    }
  }

  /**
   * Iterate through unique targets and try to load existing records.
   * Return id for the first match.
   */
  protected function existingItemId($source_item, FeedsSource $source) {
    foreach ($this->uniqueTargets($source_item) as $target => $value) {
      if ($records = $this->handler()->load(array($target => $value))) {
        return $records[0]['id'];
      }
    }
    return 0;
  }

  /**
   * Override parent::configDefaults().
   */
  public function configDefaults() {
    return array(
      'update_existing' => 0,
      'expire' => FEEDS_EXPIRE_NEVER, // Don't expire items by default.
      'mappings' => array(),
    );
  }

  /**
   * Override parent::configForm().
   */
  public function configForm(&$form_state) {
    $form['update_existing'] = array(
      '#type' => 'checkbox',
      '#title' => t('Update existing items'),
      '#description' => t('Check if existing items should be updated from the feed.'),
      '#default_value' => $this->config['update_existing'],
    );
    $period = drupal_map_assoc(array(FEEDS_EXPIRE_NEVER, 3600, 10800, 21600, 43200, 86400, 259200, 604800, 604800 * 4, 604800 * 12, 604800 * 24, 31536000), 'feeds_format_expire');
    $form['expire'] = array(
      '#type' => 'select',
      '#title' => t('Expire items'),
      '#options' => $period,
      '#description' => t('Select after how much time data records should be deleted. The timestamp target value will be used for determining the item\'s age, see Mapping settings.'),
      '#default_value' => $this->config['expire'],
    );
    return $form;
  }

  /**
   * Return the data table name for this feed.
   */
  protected function tableName() {
    return 'feeds_data_'. $this->id;
  }

  /**
   * Return the data table for this feed.
   *
   * @throws Exception $e
   *   Throws this exception if a table cannot be found and cannot be created.
   *
   * @todo: Make *Data module* throw exception when table can't be found or
   *   can't be created.
   */
  protected function table() {
    if ($table = data_get_table($this->tableName())) {
      return $table;
    }
    else {
      if ($table = data_create_table($this->tableName(), $this->baseSchema(), feeds_importer($this->id)->config['name'])) {
        return $table;
      }
    }
    throw new Exception(t('Could not create data table.'));
  }

  /**
   * Return a data handler for this table.
   *
   * Avoids a call to table() to not unnecessarily instantiate DataTable.
   */
  protected function handler() {
    data_include('DataHandler');
    feeds_include('FeedsDataHandler');
    return FeedsDataHandler::instance($this->tableName(), 'id');
  }

  /**
   * Every Feeds data table must have these elements.
   */
  protected function baseSchema() {
    return array(
      'fields' => array(
        'feed_nid' => array(
          'type' => 'int',
          'unsigned' => TRUE,
          'not null' => TRUE,
        ),
        'id' => array(
          'type' => 'serial',
          'size' => 'normal',
          'unsigned' => TRUE,
          'not null' => TRUE,
        ),
        'timestamp' => array(
          'description' => 'The Unix timestamp for the data.',
          'type' => 'int',
          'unsigned' => TRUE,
          'not null' => FALSE,
        ),
      ),
      'indexes' => array(
        'feed_nid' => array('feed_nid'),
        'id' => array('id'),
        'timestamp' => array('timestamp'),
       ),
       'primary key' => array(
         '0' => 'id',
       ),
    );
  }
}