<?php
// $Id: faceted_search_views.module,v 1.14.2.2 2008-10-21 01:56:26 davidlesieur Exp $

/**
 * @file
 * Allows to use Views to display Faceted Search results.
 */

require_once('./'. drupal_get_path('module', 'faceted_search') .'/faceted_search_ui.inc');

/**
 * Implementation of hook_faceted_search_ui_style_info().
 *
 * Return display styles based on views that use the Faceted Search argument.
 */
function faceted_search_views_faceted_search_ui_style_info() {
  $styles = array();
  $results = db_query("SELECT v.name FROM {view_view} v INNER JOIN {view_argument} a ON a.vid = v.vid WHERE a.type = 'faceted_search_results' ORDER BY v.name");
  while ($view = db_fetch_object($results)) {
    $styles[$view->name] = new faceted_search_views_style($view->name);
  }

  // Load default views.
  views_load_cache();
  $default_views = _views_get_default_views();
  foreach ($default_views as $view) {
    foreach ($view->argument as $argument) {
      if ($argument['type'] == 'faceted_search_results') {
        $styles[$view->name] = new faceted_search_views_style($view->name);
      }
    }
  }
  return $styles;
}

/**
 * Implementation of hook_views_arguments().
 */
function faceted_search_views_views_arguments() {
  $arguments['faceted_search_results'] = array(
    'name' => t('Faceted Search: Environment ID'),
    'help' => t("Filter by the current results of a Faceted Search environment. The option field allows you to sort the results by relevance score. If a sort option is selected, it is applied before all other sort criteria of the view. The higher the score, the more relevant the item."), 
    'handler' => 'faceted_search_views_results_argument_handler',
    'option' => array(
      '#type' => 'select',
      '#options' => array(
        'none' => t('No sort'),
        'ASC' => t('Sort by score - Ascending'),
        'DESC' => t('Sort by score - Descending'),
      ),
      '#default_value' => 0,
    ),
    // Note: Sort options are provided here, because a sort handler would not
    // have access to the environment id argument, and thus would not know the
    // name of the results table to get its score field (unless ugly hacks were
    // done).
  );
  return $arguments;
}

/**
 * An argument handler that updates the specified query to filter with a Faceted
 * Search environment's current results.
 */
function faceted_search_views_results_argument_handler($op, &$query, $a1, $a2 = NULL) {
  global $_faceted_search;
  
  if ($op == 'filter' && isset($_faceted_search[$a2])) {
    if ($_faceted_search[$a2]->ready()) {
      // Thanks to the above condition, this handler has no effect when there is
      // no current search results. This avoids a race condition between Views
      // and Faceted Search; Faceted Search may use this query in a subquery to
      // build its results, and Views may call this handler afterwards to filter
      // by Faceted Search's results.
      
      if ($_faceted_search[$a2]->get_results_count() > 0) {
        // Join results table.
        $join = array(
          'type' => 'inner',
          'left' => array('table' => 'node', 'field' => 'nid'),
          'right' => array('field' => 'nid'),
        );
        $query->add_table($_faceted_search[$a2]->get_results_table(), FALSE, 1, $join);

        // Apply sort option.
        if ($a1['options'] != 'none') {
          $query->add_orderby($_faceted_search[$a2]->get_results_table(), 'score', $a1['options']);
        }
      }
      else {
        $query->add_where('FALSE'); // Ensure the view shows no results.
      }
    }
  }
}

/**
 * Provides a view-based display style for search results.
 */
class faceted_search_views_style extends faceted_search_ui_style {
  // Name of the view to use with this style.
  var $_name;
  // View to use with this style (lazy loaded).
  var $_view;
  
  /**
   * Constructor.
   *
   * @param $view_name
   *   Name of the view to use with this style.
   */
  function faceted_search_views_style($view_name) {
    $this->_name = $view_name;
  }

  /**
   * Return the view to use with this style.
   */
  function get_view() {
    if (!isset($this->_view)) {
      $this->_view = views_get_view($this->_name); 
    }
    return $this->_view;
  }
  
  /**
   * Return the name of this style.
   */
  function get_label() {
    $view = $this->get_view();
    return t('Views: @view', array('@view' => $view->name));
  }

  /**
   * Return the number of nodes per page.
   */
  function get_limit() {
    $view = $this->get_view();
    if ($view->nodes_per_page > 0) {
      return $view->nodes_per_page;
    }
    // The pager is mandatory for search results, thus a valid limit required.
    return variable_get('default_nodes_main', 10);
  }

  /**
   * Apply the view's query as a subquery to filter the search results.
   *
   * Note: We use the view's count query for this purpose because the sorting
   * and field selection provided by its main query is not wanted here. The
   * view's only purpose here is to filter the search results.
   */
  function query_alter(&$query, $search) {
    $view = $this->get_view();
    $queries = views_build_view('queries', $view, array($search->get_env_id()));
    // Make sure the view's query selects node.id rather than a count. This
    // assumes that the view is counting node.id.
    $views_query = preg_replace('!count\(((DISTINCT\()?node.nid\)?)\)!', '$1', $queries['countquery']); 
    $views_query = db_rewrite_sql($views_query, 'node');
    $query->add_subquery('n.nid IN ('. $views_query .')');
  }

  /**
   * Format the search results according to this style's desire.
   */
  function format_results($search) {
    $view = $this->get_view();
    return views_build_view('embed', $view, array($search->get_env_id()), TRUE, $this->get_limit());
  }
}