<?php

/**
 * @file
 * Provides the ability to export to specific
 */

define('VIEWS_DATA_EXPORT_HEADER', 'header');
define('VIEWS_DATA_EXPORT_BODY', 'body');
define('VIEWS_DATA_EXPORT_FOOTER', 'footer');
define('VIEWS_DATA_EXPORT_FINISHED', 'finished');

define('VIEWS_DATA_EXPORT_INDEX_TABLE_PREFIX', 'views_data_export_index_');

/**
 * Implements hook_init().
 */
function views_data_export_init() {
  // We have to include our theme preprocessors here until:
  // http://drupal.org/node/1096770 is fixed.
  module_load_include('inc', 'views_data_export', 'theme/views_data_export.theme');
}

/**
 * Implementation of hook_views_api().
 */
function views_data_export_views_api() {
  return array(
    'api' => 2,
  );
}

/**
/**
 * Checks whether the passed URI identifies an export file.
 *
 * @param string $uri
 *   A file URI.
 *
 * @return bool
 *   TRUE if the URI identifies an export file, FALSE otherwise.
 */
function views_data_export_is_export_file($uri) {
  foreach (entity_load('file', FALSE, array('uri' => $uri)) as $file) {
    // See if this is an export file.
    $usages = file_usage_list($file);
    return !empty($usages['views_data_export']['eid']);
  }
  return FALSE;
}

/**
 * Implementation of hook_theme().
 */
function views_data_export_theme() {
  // Make sure that views picks up the preprocess functions.
  module_load_include('inc', 'views_data_export', 'theme/views_data_export.theme');
  $hooks = array();
  $hooks['views_data_export_feed_icon'] = array(
    'pattern' => 'views_data_export_feed_icon__',
    'variables' => array(
      'image_path' => NULL,
      'url' => NULL,
      'query' => '',
      'text' => '',
    ),
    'file' => 'theme/views_data_export.theme.inc',
  );

  $hooks['views_data_export_complete_page'] = array (
    'variables' => array(
      'file' => '',
      'errors' => array(),
      'return_url'=> '',
    ),
    'file' => 'theme/views_data_export.theme.inc',
  );

  $hooks['views_data_export_message'] = array (
    'variables' => array(
      'message' => '',
      'type' => 'info',
    ),
    'file' => 'theme/views_data_export.theme.inc',
  );

  return $hooks;
}


/**
 * Implementation of hook_cron().
 */
function views_data_export_cron() {
  views_data_export_garbage_collect();
}

/**
 * Removes any temporary index tables that have been left
 * behind. This is caused by batch processes which are
 * started but never finished.
 *
 * Removes all trace of exports from the database that
 * were created more than $expires seconds ago
 *
 * @param $expires
 *   Seconds ago. Defaults to that given in the settings.
 * @param $chunk
 *   The number of tables to test for and delete.
 *   Defaults to that given in the settings. Pass -1
 *   for this setting to remove any restriction and to
 *   garbage collect all exports.
 */
function views_data_export_garbage_collect($expires = NULL, $chunk = NULL) {
  if (lock_acquire('views_data_export_gc')) {
    if (!isset($expires)) {
      $expires = variable_get('views_data_export_gc_expires', DRUPAL_MAXIMUM_TEMP_FILE_AGE);
    }
    if (!isset($chunk)) {
      $chunk = variable_get('views_data_export_gc_chunk', 30);
    }

    if ($chunk == -1) {
      $result = db_query("SELECT eid FROM {views_data_export} WHERE time_stamp <= :timestamp ORDER BY time_stamp ASC", array(':timestamp' => REQUEST_TIME - $expires));
    }
    else {
      $result = db_query_range("SELECT eid FROM {views_data_export} WHERE time_stamp <= :timestamp ORDER BY time_stamp ASC", 0, $chunk, array(':timestamp' => REQUEST_TIME - $expires));
    }

    $eids_to_clear = array();
    foreach ($result as $row) {
      $eids_to_clear[] = $row->eid;
    }

    // We do two things to exports we want to garbage collect
    // 1. Delete the index table for it, if it is still around.
    // 2. Delete the files used during the export.
    // 3. Delete the row from the exports table.
    // 4. Delete the view from the object_cache.
    if (count($eids_to_clear)) {
      foreach ($eids_to_clear as $eid) {
        // 1. Delete index table, if it is still around for some reason
        $table = VIEWS_DATA_EXPORT_INDEX_TABLE_PREFIX . $eid;
        if (db_table_exists($table)) {
          db_drop_table($table);
        }

        // 2. Delete the files used during the export.
        foreach (views_data_export_export_list_files($eid) as $file) {
          file_delete($file, TRUE);
        }
      }

      // 3. Delete the entries in the exports table.
      db_delete('views_data_export')
        ->condition('eid', $eids_to_clear, 'IN')
        ->execute();

      // 4. Clear the cached views
      views_data_export_view_clear($eids_to_clear);
    }

    lock_release('views_data_export_gc');
  }
}

/**
 * Determines where a file is used.
 *
 * @param $eid
 *   The ID of a Views Data Export.
 *
 * @return array
 *   An array of loaded files objects used by the specified export.
 */
function views_data_export_export_list_files($eid) {
  $result = db_select('file_usage', 'f')
    ->fields('f', array('fid'))
    ->condition('id', $eid)
    ->condition('type', 'eid')
    ->condition('module', 'views_data_export')
    ->execute();
  return file_load_multiple($result->fetchCol());
}


/**
 * Batch API callback.
 * Handles all batching operations by executing the appropriate view.
 */
function _views_data_export_batch_process($export_id, $display_id, $exposed_input, &$context) {
  // Don't show the admin menu on batch page, some people don't like it.
  if (module_exists('admin_menu')) {
    module_invoke('admin_menu', 'suppress');
  }

  // Fetch the view in question from our cache
  $view = views_data_export_view_retrieve($export_id);
  $view->set_display($display_id);
  if (!empty($exposed_input)) {
    $view->set_exposed_input($exposed_input);
  }
  // Inform the data_export display which export it corresponds to and execute
  if (!isset($view->display_handler->batched_execution_state)) {
    $view->display_handler->batched_execution_state = new stdClass();
  }
  $view->display_handler->batched_execution_state->eid = $export_id;
  $view->display_handler->views_data_export_cached_view_loaded = TRUE;
  $view->execute_display($display_id);

  // Update batch api progress information
  $sandbox = $view->display_handler->batched_execution_state->sandbox;
  $context['finished'] = $sandbox['finished'];
  $context['message'] = $sandbox['message'];

  views_data_export_view_store($export_id, $view);
}


/**********/
/** CRUD **/
/**********/

/**
 * Save a new export into the database.
 */
function views_data_export_new($view_name, $view_display_id, $file) {
  // Insert new row into exports table
  $record = (object) array(
    'view_name' => $view_name,
    'view_display_id' => $view_display_id,
    'time_stamp' => REQUEST_TIME,
    'fid' => $file,
    'batch_state' => VIEWS_DATA_EXPORT_HEADER,
    'sandbox' => array(),
  );
  drupal_write_record('views_data_export', $record);
  return $record;
}


/**
 * Update an export row in the database
 */
function views_data_export_update($state) {
  // Note, drupal_write_record handles serializing
  // the sandbox field as per our schema definition
  drupal_write_record('views_data_export', $state, 'eid');
}


/**
 * Get the information about a previous export.
 */
function views_data_export_get($export_id) {
  $object = db_query("SELECT * FROM {views_data_export} WHERE eid = :eid", array(':eid' => (int)$export_id))->fetch();
  if ($object) {
    $object->sandbox = unserialize($object->sandbox);
  }
  return $object;
}

/**
 * Remove the information about an export.
 */
function views_data_export_clear($export_id) {
  db_delete('views_data_export')
    ->condition('eid', $export_id)
    ->execute();
  views_data_export_view_clear($export_id);
}


/**
 * Store a view in the object cache.
 */
function views_data_export_view_store($export_id, $view) {
  // Store a clean copy of the view.
  $_view = $view->clone_view();

  views_data_export_view_clear($export_id);
  $record = array(
    'eid' => $export_id,
    'data' => $_view,
    'updated' => REQUEST_TIME,
  );
  drupal_write_record('views_data_export_object_cache', $record);
}

/**
 * Retrieve a view from the object cache.
 */
function views_data_export_view_retrieve($export_id) {
  views_include('view');
  $data = db_query("SELECT * FROM {views_data_export_object_cache} WHERE eid = :eid", array(':eid' => $export_id))->fetch();
  if ($data) {
    $view = unserialize($data->data);
  }
  return $view;
}

/**
 * Clear a view from the object cache.
 *
 * @param $export_id
 *   An export ID or an array of export IDs to clear from the object cache.
 */
function views_data_export_view_clear($export_id) {
  db_delete('views_data_export_object_cache')
    ->condition('eid', $export_id)
    ->execute();
}