<?php
// $Id: date_authored_facet.module,v 1.11 2008-05-20 01:55:00 davidlesieur Exp $

/**
 * @file
 * Provides a facet for searching content by date of creation.
 */

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

// TODO: add setting for granularity.

/**
 * Implementation of hook_faceted_search_collect().
 */
function date_authored_facet_faceted_search_collect(&$facets, $domain, $env_id, $selection, $arg = NULL) {
  switch ($domain) {
    case 'facets':
      // If the date authored facet is allowed.
      if (!isset($selection) || isset($selection['date_authored'][1])) {
        $facets[] = new date_authored_facet();
      }
      break;

    case 'text':
      // If the date authored facet is allowed.
      if (!isset($selection) || isset($selection['date_authored'][1])) {
        // Scan the given search text for a 'date_authored:date' token, and
        // extract a category from it. Date is formatted as either YYYY,
        // YYYY-MM, or YYYY-MM-DD.
        if ($date = search_query_extract($arg, 'date_authored')) {
          $matches = array();
          // Match the three possible date formats.
          if (preg_match('/^([12][0-9][0-9][0-9])(-([01][0-9])(-([0-3][0-9]))?)?$/', $date, $matches)) {
            if (_date_authored_facet_check_date($matches[1], $matches[3], $matches[5])) {
              $path = array(); // Array to build the path of categories.
              if (isset($matches[1])) {
                // Found year.
                $path[] = new date_authored_facet_category($matches[1]);
              }
              if (isset($matches[3])) {
                // Found month.
                $path[] = new date_authored_facet_category($matches[1], $matches[3]);
              }
              if (isset($matches[5])) {
                // Found day.
                $path[] = new date_authored_facet_category($matches[1], $matches[3], $matches[5]);
              }
              if (!empty($path)) {
                // Create a facet with the date found in the search text as the
                // active category.
                $facets[] = new date_authored_facet($path);
              }
            }
          }
          // Remove the parsed token from the search text.
          $arg = search_query_insert($arg, 'date_authored');
        }
      }
      return $arg;

    case 'node':
      // If the date authored facet is allowed.
      if (!isset($selection) || isset($selection['date_authored'][1])) {
        // Convert the node's creation date into the user's timezone.
        $timestamp = $arg->created + _date_authored_facet_get_user_timezone();
        $year = gmdate('Y', $timestamp);
        $month = gmdate('n', $timestamp);
        $day = gmdate('j', $timestamp);
  
        // Build the path of categories.
        $path = array(
          new date_authored_facet_category($year),
          new date_authored_facet_category($year, $month),
          new date_authored_facet_category($year, $month, $day),
        );
  
        // Create a facet with the node's creation date as the active category.
        $facets[] = new date_authored_facet($path);
      }
      break;
  }
}

/**
 * A facet for searching content by date of creation.
 */
class date_authored_facet extends faceted_search_facet {

  /**
   * Constructor.
   */
  function date_authored_facet($active_path = array()) {
    parent::faceted_search_facet('date_authored', $active_path);
  }

  function get_id() {
    return 1; // This module provides only one facet.
  }

  function get_label() {
    return t('Date authored');
  }

  /**
   * Returns the available sort options for this facet.
   */
  function get_sort_options() {
    $options = parent::get_sort_options();
    $options['oldest'] = t('Oldest first');
    $options['latest'] = t('Latest first');
    return $options;
  }

  /**
   * Handler for the 'count' sort criteria.
   */
  function build_sort_query_count(&$query) {
    $query->add_orderby('count', 'DESC');
    $query->add_orderby('n.created', 'ASC');
  }

  /**
   * Handler for the 'oldest' sort criteria.
   */
  function build_sort_query_oldest(&$query) {
    $query->add_orderby('n.created', 'ASC');
  }

  /**
   * Handler for the 'latest' sort criteria.
   */
  function build_sort_query_latest(&$query) {
    $query->add_orderby('n.created', 'DESC');
  }

  /**
   * Returns the search text for this facet, taking into account this facet's
   * active path.
   */
  function get_text() {
    if ($category = $this->get_active_category()) {
      return $category->get_text();
    }
    return '';
  }
  
  /**
   * Updates a query for retrieving the root categories of this facet and their
   * associated nodes within the current search results. 
   *
   * @param $query
   *   The query object to update.
   *
   * @return
   *   FALSE if this facet can't have root categories.
   */
  function build_root_categories_query(&$query) {
    $timezone = _date_authored_facet_get_timezone();
    $query->add_field(NULL, "YEAR(FROM_UNIXTIME(n.created + $timezone))", 'node_created_year');
    $query->add_groupby('node_created_year');
    return TRUE;
  }
  
  /**
   * This factory method creates categories given query results that include the
   * fields selected in get_root_categories_query() or get_subcategories_query().
   *
   * @param $results
   *   $results A database query result resource.
   *
   * @return
   *   Array of categories.
   */
  function build_categories($results) {
    $categories = array();
    while ($result = db_fetch_object($results)) {
      $categories[] = new date_authored_facet_category($result->node_created_year, $result->node_created_month, $result->node_created_day, $result->count);
    }
    return $categories;
  }
}

/**
 * A category for node creation date.
 */
class date_authored_facet_category extends faceted_search_category {
  var $_year = NULL;
  var $_month = NULL;
  var $_day = NULL;
  
  /**
   * Constructs a category for the specified date.
   *
   * @param $year
   *   Year corresponding to this category.
   *
   * @param $month
   *   Month corresponding to this category. Optional, but must be specified if
   *   $day is specified.
   *
   * @param $day
   *   Day corresponding to this category. Optional.
   *
   * @param $count
   *   The number of nodes associated to this category within the current
   *   search. Optional.
   * 
   * Note: We consider the specified date as within the user's timezone.
   */
  function date_authored_facet_category($year, $month = NULL, $day = NULL, $count = NULL) {
    parent::faceted_search_category($count);
    $this->_year = $year;
    $this->_month = $month;
    $this->_day = $day;
  }

  /**
   * Return the label of this category.
   *
   * @param $html
   *   TRUE when HTML is allowed in the label, FALSE otherwise. Checking this
   *   flag allows implementors to provide a rich-text label if desired, and an
   *   alternate plain text version for cases where HTML cannot be used. The
   *   implementor is responsible to ensure adequate security filtering.
   */
  function get_label($html = FALSE) {
    if (isset($this->_day)) {
      // Format date with YYYY-MM-DD.
      $timestamp = gmmktime(0, 0, 0, $this->_month, $this->_day, $this->_year);
      $format = variable_get('date_facets_format_ymd', 'm/d/Y');
    }
    elseif (isset($this->_month)) {
      // Format date with YYYY-MM.
      $timestamp = gmmktime(0, 0, 0, $this->_month, 1, $this->_year);
      $format = variable_get('date_facets_format_ym', 'm/Y');
    }
    elseif (isset($this->_year)) {
      // Format date with YYYY.
      $timestamp = gmmktime(0, 0, 0, 1, 1, $this->_year);
      $format = variable_get('date_facets_format_y', 'Y');
    }
    if ($timestamp) {
      return format_date($timestamp, 'custom', $format, 0);
    }
  }

  function get_text() {
    $text = sprintf('%04d', $this->_year);
    if (isset($this->_month)) {
      $text .= sprintf('-%02d', $this->_month);
      if (isset($this->_day)) {
        $text .= sprintf('-%02d', $this->_day);
      }
    }
    return $text;
  }
  
  /**
   * Updates a query for retrieving the subcategories of this category and their
   * associated nodes within the current search results. 
   *
   * This only needs to be overridden for hierarchical facets.
   *
   * @param $query
   *   The query object to update.
   *
   * @return
   *   FALSE if this facet can't have subcategories.
   */
  function build_subcategories_query(&$query) {
    $timezone = _date_authored_facet_get_timezone();
    if (isset($this->_day)) {
      return FALSE; // No subcategories.
    }
    if (isset($this->_month)) {
      $from = sprintf("'%04d-%02d-01 00:00:00'", $this->_year, $this->_month);
      $query->add_field(NULL, "YEAR(FROM_UNIXTIME(n.created + $timezone))", 'node_created_year');
      $query->add_field(NULL, "MONTH(FROM_UNIXTIME(n.created + $timezone))", 'node_created_month');
      $query->add_field(NULL, "DAY(FROM_UNIXTIME(n.created + $timezone))", 'node_created_day');
      $query->add_where("(n.created + $timezone >= UNIX_TIMESTAMP($from))");
      $query->add_where("(n.created + $timezone < UNIX_TIMESTAMP($from + INTERVAL 1 MONTH))");
      $query->add_groupby('node_created_day'); // Needed for counting matching nodes.
      return TRUE;
    }
    if (isset($this->_year)) {
      $from = sprintf("'%04d-01-01 00:00:00'", $this->_year);
      $query->add_field(NULL, "YEAR(FROM_UNIXTIME(n.created + $timezone))", 'node_created_year');
      $query->add_field(NULL, "MONTH(FROM_UNIXTIME(n.created + $timezone))", 'node_created_month');
      $query->add_where("(n.created + $timezone >= UNIX_TIMESTAMP($from))");
      $query->add_where("(n.created + $timezone < UNIX_TIMESTAMP($from + INTERVAL 1 YEAR))");
      $query->add_groupby('node_created_month'); // Needed for counting matching nodes.
      return TRUE;
    }
    return FALSE; // Unreachable, unless something is wrong...
  }

  /**
   * Updates a query for selecting nodes matching this category.
   *
   * @param $query
   *   The query object to update.
   */
  function build_results_query(&$query) {
    $timezone = _date_authored_facet_get_timezone();
    if (isset($this->_day)) {
      $from = sprintf("'%04d-%02d-%02d 00:00:00'", $this->_year, $this->_month, $this->_day);
      $query->add_where("(n.created + $timezone >= UNIX_TIMESTAMP($from))");
      $query->add_where("(n.created + $timezone < UNIX_TIMESTAMP($from + INTERVAL 1 DAY))");
    }
    elseif (isset($this->_month)) {
      $from = sprintf("'%04d-%02d-01 00:00:00'", $this->_year, $this->_month);
      $query->add_where("(n.created + $timezone >= UNIX_TIMESTAMP($from))");
      $query->add_where("(n.created + $timezone < UNIX_TIMESTAMP($from + INTERVAL 1 MONTH))");
    }
    elseif (isset($this->_year)) {
      $from = sprintf("'%04d-01-01 00:00:00'", $this->_year);
      $query->add_where("(n.created + $timezone >= UNIX_TIMESTAMP($from))");
      $query->add_where("(n.created + $timezone < UNIX_TIMESTAMP($from + INTERVAL 1 YEAR))");
    }
  }
}

/**
 * Returns the applicable timezone offset (in seconds) for date comparisons in
 * database queries.
 */
function _date_authored_facet_get_timezone() {
  return _date_authored_facet_get_user_timezone() - _date_authored_facet_get_system_timezone();
}

/**
 * Returns current user's timezone offset (in seconds).
 */
function _date_authored_facet_get_user_timezone() {
  global $user;
  if (variable_get('configurable_timezones', 1) && $user->uid && strlen($user->timezone)) {
    return $user->timezone;
  }
  else {
    return variable_get('date_default_timezone', 0);
  }
}

/**
 * Returns the database system's timezone offset (in seconds).
 *
 * This hack is used to cancel MySQL's timezone conversions when it converts
 * dates to/from Unix timestamps. We could avoid this if MySQL had functions
 * that worked directly in UTC (see http://bugs.mysql.com/bug.php?id=28961).
 */
function _date_authored_facet_get_system_timezone() {
  static $offset = NULL;
  if (!isset($offset)) {
    $system = db_result(db_query("SELECT UNIX_TIMESTAMP('2007-01-01 00:00:00')"));
    $offset = 1167609600 - $system; // Find offset from the timestamp for 2007-01-01 00:00:00 UTC.
  }
  return $offset;
}

/**
 * Checks the validity of a date or partial date.
 */
function _date_authored_facet_check_date($year = NULL, $month = NULL, $day = NULL) {
  if (!isset($year) || !is_numeric($year) || $year < 1) {
    return FALSE;
  }
  if (isset($month) && (!is_numeric($month) || $month < 1 || $month > 12)) {
    return FALSE;
  }
  if (isset($day) && (!isset($month) || !is_numeric($month) || !is_numeric($day) || !checkdate($month, $day, $year))) {
    return FALSE;
  }
  
  return TRUE;
}