hosting_site_backup_manager.module

<?php

/**
 * @file
 * Hosting site backup manager module.
 *
 * Adds a backup tab to the site node.
 */

/**
 * Implements of hook_menu().
 *
 * @return array
 *   An array of menu items.
 */
function hosting_site_backup_manager_menu() {
  $items = array();

  $items['admin/hosting/backup_manager'] = array(
    'title' => 'Backup manager',
    'description' => 'Configure backup manager',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('hosting_site_backup_manager_settings'),
    'access arguments' => array('administer hosting site backup manager'),
    'type' => MENU_LOCAL_TASK
  );

  $items['node/%hosting_site_node/backups'] = array(
    'title' => 'Backups',
    'description' => 'List of backups of this website',
    'page callback' => 'hosting_site_backup_manager_page',
    'page arguments' => array(1),
    'access callback' => 'node_access',
    'access arguments' => array('view', 1),
    'type' => MENU_LOCAL_TASK,
  );

  $items['node/%hosting_site_node/ajax/backups'] = array(
    'title' => 'Backup list',
    'description' => 'AJAX callback for refreshing backups list',
    'page callback' => 'hosting_site_backup_manager_ajax_list',
    'page arguments' => array(1),
    'access callback' => 'node_access',
    'access arguments' => array('view', 1),
    'type' => MENU_CALLBACK,
  );

  $items['node/%hosting_site_node/backup/download/%'] = array(
    'title' => 'Download backup',
    'description' => 'Download the selected backup',
    'page callback' => 'hosting_site_backup_manager_download',
    'page arguments' => array(1, 4),
    'access callback' => 'node_access',
    'access arguments' => array('view', 1),
    'type' => MENU_CALLBACK,
  );

  $items['node/%hosting_site_node/backup/delete/%'] = array(
    'title' => 'Delete backup',
    'description' => 'Delete the selected backup',
    'page callback' => 'hosting_site_backup_manager_delete',
    'page arguments' => array(1, 4),
    'access callback' => 'node_access',
    'access arguments' => array('view', 1),
    'type' => MENU_CALLBACK,
  );

  $items['node/%hosting_site_node/backup/restore/%'] = array(
    'title' => 'Restore backup',
    'description' => 'Restore the selected backup',
    'page callback' => 'hosting_site_backup_manager_restore',
    'page arguments' => array(1, 4),
    'access callback' => 'node_access',
    'access arguments' => array('view', 1),
    'type' => MENU_CALLBACK,
  );

  $items['node/%hosting_site_node/backup/export/%'] = array(
    'title' => 'Export backup',
    'description' => 'Export the selected backup',
    'page callback' => 'hosting_site_backup_manager_export',
    'page arguments' => array(1, 4),
    'access callback' => 'node_access',
    'access arguments' => array('view', 1),
    'type' => MENU_CALLBACK,
  );

  return $items;
}

/**
 * Implementation of hook_perm
 */
function hosting_site_backup_manager_perm() {
  return array('administer hosting site backup manager');
}

/**
 * Placeholder function for additional delete checks.
 *
 * @param node $site
 *   The site node object.
 * @param int $bid
 *   The backup id.
 *
 * @return string
 *   A confirmation form or a error string.
 */
function hosting_site_backup_manager_delete($site, $bid) {
  // Get the filename.
  $source = db_fetch_object(db_query("SELECT filename FROM {hosting_site_backups} WHERE site=%d AND bid=%d ORDER BY timestamp DESC", $site->nid, $bid));

  if ($source) {
    // Return a confirmation form.
    $output = drupal_get_form('hosting_site_backup_manager_confirm_delete', $source->filename, $site->nid, $bid);
  }
  else {
    $output = t('A valid backup could not be found.');
  }
  return $output;
}

/**
 * Function that renders a confirmation form for the selected deletetion.
 *
 * @param arrays $form_state
 *   The form state array. Changes made to this variable will have no effect.
 * @param string $filename
 *   The backup filename to delete.
 * @param int $sitenid
 *   The selected site node id.
 * @param int $bid
 *   The backup id.
 *
 * @return string
 *   A confirmation form.
 */
function hosting_site_backup_manager_confirm_delete($form_state, $filename, $sitenid, $bid) {

  // Add the hosting_task javascript,
  // so we can use the confirm form functionality.
  drupal_add_js(drupal_get_path('module', 'hosting_task') . '/hosting_task.js');

  // Get the backup data.
  $source = db_fetch_object(db_query("SELECT * FROM {hosting_site_backups} WHERE site=%d AND bid=%d", $sitenid, $bid));

  // Build the form.
  $form = array();
  $form['#filename'] = $filename;
  $form['#sitenid'] = $sitenid;
  $form['#bid'] = $bid;

  // Not the best formatted code, but suffices for now.
  $form['explanation'] = array(
    '#type' => 'markup',
    '#value' => '<h2>' . t('Backup information') . '</h2>' . t('Backup description:<br /> %description', array('%description' => filter_xss($source->description))) . '<br />',
    '#weight' => -10,
  );

  $form['date'] = array(
    '#type' => 'markup',
    '#value' => t('Backup was created on:<br /> %date', array('%date' => format_date($source->timestamp, 'short'))) . '<br /><br />',
    '#weight' => -8,
  );

  // Build the confirmation form.
  $form = confirm_form(
  $form,
  t('Are you sure you want to delete this backup?', array()),
      'node/' . $sitenid . '/backup',
  t('This action cannot be undone.'),
  t('Delete'),
  t('Cancel'),
      'hosting_site_backup_manager_confirm_delete');

  // Copied from hosting_task.module
  // Add an extra class to the actions to allow us to disable
  // the cancel link via javascript for the modal dialog.
  $form['actions']['#prefix'] = '<div id="hosting-task-confirm-form-actions" class="container-inline">';

  return $form;
}

/**
 * The form submit function.
 */
function hosting_site_backup_manager_confirm_delete_submit($form, &$form_state) {

  // The deletion has been confirmed, process the result.
  $filename = $form['#filename'];
  $sitenid = $form['#sitenid'];
  $bid = $form['#bid'];

  // Add the hosting task.
  hosting_add_task($sitenid, 'backup-delete', array($bid => $filename));

  $form_state['redirect'] = 'node/' . $sitenid . '/backup';
  modalframe_close_dialog();
}

/**
 * Placeholder  function for additional restore checks.
 *
 * @param node $site
 *   The site node object.
 * @param int $bid
 *   The backup id.
 *
 * @return string
 *   A confirmation form.
 */
function hosting_site_backup_manager_restore($site, $bid) {
  // @todo: Build in extra checks.
  $output = drupal_get_form('hosting_site_backup_manager_confirm_restore', $site->nid, $bid);

  return $output;
}

/**
 * Function that renders a confirmation form for the selected deletetion.
 *
 * @param array $form_state
 *   The form state array. Changes made to this variable will have no effect.
 * @param int $sitenid
 *   The selected site node id.
 * @param int $bid
 *   The backup id
 *
 * @return string
 *   A confirmation form.
 */
function hosting_site_backup_manager_confirm_restore($form_state, $sitenid, $bid) {
  // Add the hosting_task javascript,
  // so we can use the confirm form functionality.
  drupal_add_js(drupal_get_path('module', 'hosting_task') . '/hosting_task.js');

  // Build the form.
  $form = array();
  $form['#sitenid'] = $sitenid;
  $form['#bid'] = $bid;

  // Get the backup data.
  $source = db_fetch_object(db_query("SELECT * FROM {hosting_site_backups} WHERE site=%d AND bid=%d", $sitenid, $bid));

  // Not the best formatted code, but suffices for now.
  $form['explanation'] = array(
    '#type' => 'markup',
    '#value' => '<h2>' . t('Backup information') . '</h2>' . t('Backup description:<br /> %description', array('%description' => filter_xss($source->description))) . '<br />',
    '#weight' => -10,
  );

  $form['date'] = array(
    '#type' => 'markup',
    '#value' => t('Backup was created on:<br /> %date', array('%date' => format_date($source->timestamp, 'short'))) . '<br /><br />',
    '#weight' => -8,
  );

  // Build the confirmation form.
  $form = confirm_form(
  $form,
  t('Are you sure you want to restore this backup?', array()),
        'node/' . $sitenid . '/backup',
  t('This action cannot be undone.'),
  t('Restore'),
  t('Cancel'),
        'hosting_site_backup_manager_confirm_restore');

  // Copied from hosting_task.module
  // add an extra class to the actions to allow us to
  // disable the cancel link via javascript for the modal dialog.
  $form['actions']['#prefix'] = '<div id="hosting-task-confirm-form-actions" class="container-inline">';
  return $form;
}

/**
 * The form submit function.
 */
function hosting_site_backup_manager_confirm_restore_submit($form, &$form_state) {
  // The restoration has been confirmed, process the result.
  $sitenid = $form['#sitenid'];
  $bid = $form['#bid'];
  hosting_add_task($sitenid, 'restore', array('bid' => $bid));
  $form_state['redirect'] = 'node/' . $sitenid . '/backup';
  modalframe_close_dialog();
}

/**
 * The form submit function.
 */
function hosting_site_backup_manager_export($site, $bid) {
  // Get the filename.
  $source = db_fetch_object(db_query("SELECT filename FROM {hosting_site_backups} WHERE site=%d AND bid=%d ORDER BY timestamp DESC", $site->nid, $bid));

  // Start the task.
  hosting_add_task($site->nid, 'export_backup', array('backup' => $source->filename));

  // Redirect to the backups page.
  drupal_goto('node/' . $site->nid . '/backups');
}

/**
 * Helper function to get the root directory where backups are exported.
 * @todo: make this configurable again, the provision_site_backup_manager needs to be in sync.
 */
function _hosting_site_backup_manager_get_backup_export_root() {
  $root = '/var/aegir/backup-exports';
  return $root;
}

/**
 * Function to download a backup file.
 *
 * @param node $site
 *   The site node object.
 * @param int $bid
 *   The backup id.
 *
 * @return file
 *   A file or a 404 page.
 */
function hosting_site_backup_manager_download($site, $bid) {
  // @todo: check if the bid is not in a task.
  $source = db_fetch_object(db_query("SELECT filename FROM {hosting_site_backups} WHERE site=%d AND bid=%d ORDER BY timestamp DESC", $site->nid, $bid));

  if ($source) {
    $backup_root = _hosting_site_backup_manager_get_backup_export_root();
    $symlink = $backup_root . '/' . basename($source->filename);

    if ($fd = @fopen($symlink, 'rb')) {
      // Construct filename.
      $filename = basename($source->filename);

      // Set headers.
      header("Cache-Control: public");
      header("Content-Description: File Transfer");
      header("Content-Disposition: attachment; filename=\"$filename\"");
      header("Content-Type: application/octet-stream");
      header("Content-Transfer-Encoding: binary");

      while (!feof($fd)) {
        print fread($fd, 1024);
      }
      fclose($fd);
      // File downloaded so delete the file.
      // Start the task.
      hosting_add_task($site->nid, 'remove_export_backup', array('export' => $symlink));
      exit();
    }
    else {
      drupal_not_found();
    }
  }
  else {
    drupal_not_found();
  }
}

/**
 * Show a list of backups for a website.
 *
 * @param node $site
 *   The site node.
 *
 * @return string
 *   A theme table with a list of backups.
 */
function hosting_site_backup_manager_page($site) {
  // Add the js.
  drupal_add_js(drupal_get_path('module', 'hosting_site_backup_manager') . '/hosting_site_backup_manager.js');

  $settings['hostingSiteBackupManager'] = array(
    'nid' => $site->nid,
  );
  drupal_add_js($settings, 'setting');

  $output = '<div id="hosting-site-backup-manager-backupstable">';
  $output .= hosting_site_backup_manager_backups_table($site);
  $output .= '</div>';

  return $output;
}

/**
 * Page callback for backups table via AJAX.
 */
function hosting_site_backup_manager_ajax_list($site) {
  $return['markup'] = hosting_site_backup_manager_backups_table($site);
  drupal_json($return);
  exit();
}

/**
 * Prepare a table of available backups.
 */
function hosting_site_backup_manager_backups_table($site) {
  global $user;

  // Determine client name.
  $client = hosting_client_node_load($site->client);

  // Determine site's profile name
  $profile = node_load($site->profile);

  $ishostmaster = ($profile->short_name == 'hostmaster');
  $isdeleted = $site->site_status == HOSTING_SITE_DELETED;

  $headers[] = t('Backup');
  $headers[] = array('data' => t('Actions'), 'class' => 'hosting-actions');

  $rows = array();

  // Only allow actions when there's no backup delete or
  // restore task running for this node.
  $buttonstatus = !(hosting_task_outstanding($site->nid, 'backup-delete') || hosting_task_outstanding($site->nid, 'restore') || hosting_task_outstanding($site->nid, 'export_backup') || hosting_task_outstanding($site->nid, 'remove_export_backup'));

  // TODO Make the table reload automatically.
  $result = db_query("SELECT bid, description, filename, size, timestamp FROM {hosting_site_backups} WHERE site=%d ORDER BY timestamp DESC", $site->nid);

  if ($ishostmaster) {
    $output = t("Feature not available for the Hostmaster site.");
    return $output;
  }

  if (db_affected_rows($result) == 0) {
    $output = t("No backups available.");
    $options = array(
      'query' => array('token' => drupal_get_token($user->uid)),
      'attributes' => array('class' => 'hosting-button-dialog'),
    );

    $output .= '&nbsp;' . l(t('Create backup'), 'node/' . $site->nid . '/site_backup', $options);
    return $output;
  }

  while ($object = db_fetch_object($result)) {
    $row = array();
    $row['description'] = filter_xss($object->description) . "<br />" . format_size($object->size) . " - " . format_date($object->timestamp, 'short');

    $actions = array();
    // @todo: Add check if the backup can be restored to current platform?
    /* Add download button */
    $downloadstatus = (_hosting_site_backup_manager_isfileavailable($site, $object->bid) && !hosting_task_outstanding($site->nid, 'remove_export_backup'));
    $actions['download'] = _hosting_task_button(t('Get'), 'node/' . $site->nid . '/backup/download/' . $object->bid, t('Download the backup'), '', $downloadstatus, FALSE, FALSE);

    /* Add export backup button */
    $exportstatus = ($buttonstatus && !$downloadstatus);
    $actions['export_backup'] = _hosting_task_button(t('Export'), 'node/' . $site->nid . '/backup/export/' . $object->bid, t('Make the backup exportable'), '', $exportstatus, FALSE, FALSE);

    /* Add delete button */
    $actions['delete'] = _hosting_task_button(t('Delete'), 'node/' . $site->nid . '/backup/delete/' . $object->bid, t('Delete the backup'), '', $buttonstatus, TRUE, FALSE);

    /* Add restore button only for non-Hostmaster, non-deleted sites */
    $restorestatus = ($buttonstatus && !$ishostmaster && !$isdeleted);
    $actions['restore'] = _hosting_task_button(t('Restore'), 'node/' . $site->nid . '/backup/restore/' . $object->bid, t('Restore the backup'), '', $restorestatus, TRUE, FALSE);

    $row['actions'] = array(
      'data' => implode('', $actions),
      'class' => 'hosting-actions',
    );

    $rows[] = array(
      'data' => $row,
      'class' => $info['class'],
    );
  }

  $output .= theme('table', $headers, $rows, array('class' => 'hosting-table'));
  return $output;
}

/**
 * Implements hook_hosting_tasks().
 */
function hosting_site_backup_manager_hosting_tasks() {
  $tasks = array();

  $tasks['site']['export_backup'] = array(
    'title' => t('Export Backup'),
    'description' => t('Make a backup available for download.'),
    'dialog' => TRUE,
    'hidden' => TRUE,
  );

  $tasks['site']['remove_export_backup'] = array(
    'title' => t('Remove Export Backup'),
    'description' => t('Remove an exported backup, making it unavailable for download.'),
    'dialog' => FALSE,
    'hidden' => TRUE,
  );

  return $tasks;
}

/**
 * Helper function to check if a backup file is available.
 */
function _hosting_site_backup_manager_isfileavailable($site, $bid) {
  $result = FALSE;

  // @todo: check if the bid is not in a task.
  $source = db_fetch_object(db_query("SELECT filename FROM {hosting_site_backups} WHERE site=%d AND bid=%d ORDER BY timestamp DESC", $site->nid, $bid));

  if ($source) {
    // Get Document Root.
    $root = _hosting_site_backup_manager_get_backup_export_root();
    $file = $root . '/' . basename($source->filename);

    if (file_exists($file)) {
      return TRUE;
    }
  }

  return $result;
}

/**
 * Remove backup links if they persist beyond a timeout.
 *
 * They should normally be cleared directly after download.
 *
 * Implements hook_cron().
 */
function hosting_site_backup_manager_cron() {
  // Get Document Root.
  $backup_root = _hosting_site_backup_manager_get_backup_export_root();
  $backup_export_expire_timeout = 60 * 10;
  if (!is_dir($backup_root)) {
    return;
  }

  try {
    // Loop the client names that have a dir under the backup root.
    $iterator = new DirectoryIterator($backup_root);
    foreach ($iterator as $path) {
      if ($path->isDot() || !$path->isDir()) {
        continue;
      }

      // Loop all files in the client's backup dir.
      $iterator2 = new DirectoryIterator($path->getPathname());
      foreach ($iterator2 as $path2) {
        if ($path2->isDot() || !$path2->isFile()) {
          continue;
        }

        // Get the inode Change time, not to be confused with the modified time.
        // When the inode changed, not the content. e.g. when the extra hardlink was added to the inode.
        if ($path2->getCTime() < (time() - $backup_export_expire_timeout)) {
          echo "wanna unlink: " . $path2->getPathname();
          watchdog('hosting_site_backup_manager',
                  "Unlinking leftover exported backup: @pathname ",
                  array('@pathname' => $path2->getPathname()));
          unlink($path2->getPathname());
        }

        // Were now using hardlinks, but incase we ever want to switch:
        // For symlinks, $path2->getCTime() returns that of the link target not the link itself.
        // $link_stats = lstat($path2->getPathname());
        // if ($link_stats['mtime'] < (time() - $backup_export_expire_timeout)) {
      }
    }
  } catch (UnexpectedValueException $e) {
    // TODO: convert to watchdog_exception for D7
    watchdog('hosting_site_backup_manager',
            nl2br(check_plain($e->getMessage())),
            NULL,
            WATCHDOG_WARNING);
  }
}

/**
 * Configuration form for backup schedules
 */
function hosting_site_backup_manager_settings() {

  $form['garbage_collection'] = array(
    '#type' => 'fieldset',
    '#title' => t('Garbage colleciton'),
    '#collapsible' => TRUE,
    '#collapsed' => FALSE,
  );

  $form['garbage_collection']['hosting_backup_gc_default_enabled'] = array(
    '#type' => 'checkbox',
    '#title' => t('Enable backup garbage collection'),
    '#description' => t('Set the options below before enabling the garbage collection of old backups.'),
    '#default_value' => variable_get('hosting_backup_gc_default_enabled', FALSE),
  );

  $form['garbage_collection']['hosting_backup_gc_intervals'] = array(
    '#tree' => TRUE,
    '#theme' => 'hosting_backup_gc_intervals_table',
    '#element_validate' => array('hosting_backup_gc_intervals_element_validate'),
  );

  $form['garbage_collection']['hosting_backup_gc_intervals']['example'] = array(
    '#type' => 'fieldset',
    '#title' => t('Example'),
    '#weight' => 5,
    '#collapsible' => TRUE,
    '#collapsed' => TRUE,
    '#description' => _hosting_backup_gc_example(),
  );
  $intervals = array(
    '' => t('n/a'),
    strtotime('1 hour', 0) => t('Hours'),
    strtotime('1 day',  0) => t('Days'),
    strtotime('1 week', 0) => t('Weeks'),
    strtotime('1 year', 0) => t('Years'),
  );

  $default_intervals = variable_get('hosting_backup_gc_intervals', array());
  ksort($default_intervals);

  // Add the empty row:
  $default_intervals[] = array(
    'older_than' => array(
      'number' => 1,
      'interval' => '',
    ),
    'keep_per' => array(
      'number' => 1,
      'interval' => '',
    ),
  );

  $i = 0;

  foreach ($default_intervals as $interval) {

    $form['garbage_collection']['hosting_backup_gc_intervals'][$i]['older_than']['number'] = array(
      '#type' => 'select',
      '#options' => drupal_map_assoc(range(1, 365)),
      '#default_value' => isset($interval['older_than']['number']) ? $interval['older_than']['number'] : 1,
      '#attributes' => array(
        'class' => 'hosting-backup-gc-inline',
      ),
    );

    $form['garbage_collection']['hosting_backup_gc_intervals'][$i]['older_than']['interval'] = array(
      '#type' => 'select',
      '#options' => $intervals,
      '#default_value' => isset($interval['older_than']['interval']) ? $interval['older_than']['interval'] : '',
      '#attributes' => array(
        'class' => 'hosting-backup-gc-inline',
      ),
    );

    $form['garbage_collection']['hosting_backup_gc_intervals'][$i]['keep_per']['number'] = array(
      '#type' => 'select',
      '#options' => drupal_map_assoc(range(1, 365)),
      '#default_value' => isset($interval['keep_per']['number']) ? $interval['keep_per']['number'] : 1,
      '#attributes' => array(
        'class' => 'hosting-backup-gc-inline',
      ),
    );

    $form['garbage_collection']['hosting_backup_gc_intervals'][$i]['keep_per']['interval'] = array(
      '#type' => 'select',
      '#options' => $intervals,
      '#default_value' => isset($interval['keep_per']['interval']) ? $interval['keep_per']['interval'] : '',
      '#attributes' => array(
        'class' => 'hosting-backup-gc-inline',
      ),
    );

    $i++;
  }

  return system_settings_form($form);
}

function hosting_backup_gc_intervals_element_validate($element, &$form_state) {
  $values = $form_state['values'][$element['#parents'][0]];

  // Build an array of the non-empty ones.
  $new_values = array();
  foreach ($values as $val) {
    if (!empty($val['older_than']['interval']) && !empty($val['keep_per']['interval'])) {
      // Compute the key
      $key = $val['older_than']['number'] * $val['older_than']['interval'];
      $new_values[$key] = $val;
    }
  }
  // Sort the new values.
  asort($new_values);
  // Set the new values.
  form_set_value($element, $new_values, $form_state);
}

/**
 * Implementation of hook_hosting_queues
 *
 * Return a list of queues that this module needs to manage.
 */
function hosting_site_backup_manager_hosting_queues() {
  $queue['backup_gc'] = array(
    'name' => t('Backup GC'),
    'description' => t('Process the garbage collection of backups.'),
    'type' => 'batch',  # run queue sequentially. always with the same parameters.
    'frequency' => strtotime("1 hour", 0),
    'min_threads' => 6,
    'max_threads' => 12,
    'threshold' => 100,
    'total_items' => hosting_site_count(),
    'singular' => t('site'),
    'plural' => t('sites'),
  );
  return $queue;
}


/**
 * The main queue callback for the backup garbage collection.
 */
function hosting_backup_gc_queue($count) {
  // Early exit if we are disabled.
  if (!variable_get('hosting_backup_gc_default_enabled', FALSE)) {
    return;
  }

  // Get the settings:
  $intervals = variable_get('hosting_backup_gc_intervals', array());
  ksort($intervals);
  // Early exit if we've no work to do.
  if (empty($intervals)) {
    return;
  }

  // Otherwise loop over all the hosted sites.
  $sites = hosting_backup_gc_get_sites($count);

  foreach ($sites as $site) {
    // Get a list of backups.
    $backups = hosting_backup_gc_backup_list($site->nid);
    $backups_to_remove = hosting_backup_gc_compute_backups_to_remove($intervals, $backups);

    // Add the backup delete task for the backups to remove
    if (!empty($backups_to_remove)) {
      hosting_add_task($site->nid, 'backup-delete', $backups_to_remove);
    }

    hosting_backup_gc_site_touch($site->nid);
  }
}

/**
 * Get sites that need to be checked for backup GC.
 */
function hosting_backup_gc_get_sites($limit = 5) {
  $sites = array();
  $result = db_query("SELECT n.nid FROM {node} n LEFT JOIN {hosting_site} s ON n.nid = s.nid LEFT JOIN {hosting_backup_gc_sites} gc ON n.nid = gc.site_id WHERE n.type='site' and s.status = %d ORDER BY gc.last_gc ASC, n.nid ASC limit %d", HOSTING_SITE_ENABLED, $limit);
  while ($nid = db_fetch_object($result)) {
    $sites[$nid->nid] = node_load($nid->nid);
  }
  return $sites;
}

/**
 * Retrieve a list of backup generated for a site.
 *
 * @param site
 *   The node if of the site backups are being retrieved for
 * @return
 *   An associative array of backups existing for the site, indexed by bid and sorted reverse chronologically.
 */
function hosting_backup_gc_backup_list($site) {
  $result = db_query("SELECT bid, filename, timestamp FROM {hosting_site_backups} WHERE site=%d ORDER BY timestamp DESC", $site);
  while ($object = db_fetch_object($result)) {
    $backups[$object->bid] = $object;
  }
  return $backups;
}

/**
 * Compute which backups to remove.
 */
function hosting_backup_gc_compute_backups_to_remove($intervals, $backups) {
  $to_remove = array();

  foreach ($intervals as $interval) {
    // Find the backups that are older than specified in the interval
    $backups_to_consider = array();
    // The $pockets array will store keep a record of which backups we have,
    // two backups in a pocket means that the older one will have to go...
    $pockets = array();
    foreach ($backups as $backup) {
      if ($backup->timestamp < (time() - $interval['older_than']['number'] * $interval['older_than']['interval'])) {
        $backups_to_consider[] = $backup;
      }
    }
    foreach ($backups_to_consider as $backup) {
      // Now compute which backups we should be removing.
      $pocket = floor((time() - $backup->timestamp) / ($interval['keep_per']['number'] * $interval['keep_per']['interval']));
      // If there is not a backup in this pocket, mark it, otherwise add it to the list to delete.
      if (empty($pockets[$pocket])) {
        $pockets[$pocket] = TRUE;
      }
      else {
        $to_remove[$backup->bid] = $backup->filename;
      }
    }
  }

  return $to_remove;
}

/**
 * Mark a site as having its backups garbage collected.
 */
function hosting_backup_gc_site_touch($site_id, $timestamp = NULL) {
  if (is_null($timestamp)) {
    $timestamp = time();
  }
  $record = array('site_id' => $site_id, 'last_gc' => $timestamp);
  if (db_result(db_query('SELECT count(*) FROM {hosting_backup_gc_sites} WHERE site_id = %d', $record['site_id']))) {
    // Update
    drupal_write_record('hosting_backup_gc_sites', $record, 'site_id');
  }
  else {
    // Insert
    drupal_write_record('hosting_backup_gc_sites', $record);
  }
}

/**
 * Implementation of hook_theme().
 */
function hosting_site_backup_manager_theme() {
  $handlers = array();

  $handlers['hosting_backup_gc_intervals_table'] = array(
    'arguments' => array(
      'form' => array(),
    ),
  );

  return $handlers;
}

/**
 * Theme implementation of our form element of intervals.
 */
function theme_hosting_backup_gc_intervals_table($form) {
  $output = '';
  drupal_add_css(drupal_get_path('module', 'hosting_site_backup_manager') . '/hosting_site_backup_manager.admin.css');
  $rows = array();

  foreach (element_children($form) as $i) {
    if ($form[$i]['#type'] == 'fieldset') {
      continue;
    }
    $row = array();
    $row[] = array('data' => t('For backups older than'), 'class' => 'hosting-backup-gc-narrow-first');
    $row[] = drupal_render($form[$i]['older_than']);
    $row[] = array('data' => t('Keep 1 backup per'), 'class' => 'hosting-backup-gc-narrow-second');
    $row[] = drupal_render($form[$i]['keep_per']);
    $rows[] = $row;
  }

  $output .= theme('table', NULL, $rows);
  $output .= drupal_render($form);
  return $output;
}


/**
 * Generate example tekst for garbage collection intervals.
 *
 * @return string HTML
 */
function _hosting_backup_gc_example() {
  $now = time();

  // Introduction text
  $output = '<p>' . t("This page provides an example of how the current backup garbage collection settings affect stored backups.") . '<br />';
  $output .= t("The backups listed below are dummies (they don't represent real backups), but they show how many backups would be kept for a typical site over a given period.") . '</p>';

  // Get current interval settings
  $intervals = variable_get('hosting_backup_gc_intervals', array());
  ksort($intervals);
  if (empty($intervals)) {
    $output .= '<p>' . t('<strong>No garbage collection intervals found.</strong> Please configure some options first.') . '</p>';
    return $output;
  }

  // Get history (how long ago to display backups for)
  $interval_keys = array_keys($intervals);
  rsort($interval_keys);
  $id = $interval_keys[0];
  $history = ($intervals[$id]['older_than']['number'] * $intervals[$id]['older_than']['interval']) + ($intervals[$id]['keep_per']['number'] * $intervals[$id]['keep_per']['interval'] * 5);

  // Get backup queue configuration
  $default_backup_interval = variable_get('hosting_backup_queue_default_interval', strtotime('1 day', 0));
  $period = array();
  switch ($default_backup_interval) {
    case '3600':
      $period['value'] = -1;
      $period['unit'] = 'hours';
      break;
    case '21600':
      $period['value'] = -6;
      $period['unit'] = 'hours';
      break;
    case '43200':
      $period['value'] = -12;
      $period['unit'] = 'hours';
      break;
    case '86400':
      $period['value'] = -1;
      $period['unit'] = 'days';
      break;
    case '604800':
      $period['value'] = -1;
      $period['unit'] = 'weeks';
      break;
    case '2419200':
      $period['value'] = -4;
      $period['unit'] = 'weeks';
      break;
    case '31536000':
      $period['value'] = -1;
      $period['unit'] = 'years';
      break;
  }

  // Create a list of dummy backups (based on the default interval)
  $number_backups = $history / $default_backup_interval;
  $backups = array();
  $i = 0;
  while ($i < $number_backups) {
    $backups[$i]['time'] = strtotime(($period['value'] * $i) . ' ' . $period['unit']);
    $backups[$i]['date'] = date('Y-m-d H:i:s', $backups[$i]['time']);
    $i++;
  }

  // Delete dummy backups based on configured intervals
  foreach ($intervals as $interval) {
    $pockets = array();
    foreach ($backups as $id => $backup) {
      if ($backup['time'] < ($now - $interval['older_than']['number'] * $interval['older_than']['interval'])) {
        $pocket = floor($backup['time'] / ($interval['keep_per']['number'] * $interval['keep_per']['interval']));
        if (empty($pockets[$pocket])) {
          $pockets[$pocket] = TRUE;
        }
        else {
          unset($backups[$id]);
        }
      }
    }
  }

  // Get list of backup dates
  $items = array();
  foreach ($backups as $backup) {
    $items[] = $backup['date'];
  }
  $items[] = '...';

  // Display remaining backups
  $output .= theme('item_list', $items, t('Backups'));
  return $output;
}