/**

*

* @package search

* @version $Id: search.php 8782 2008-08-23 17:20:55Z acydburn $

* @copyright (c) 2005 phpBB Group

* @license http://opensource.org/licenses/gpl-license.php GNU Public License

*

*/

/**

* @ignore

*/

if (!defined('IN_PHPBB'))

{

	exit;

}

/**

* @ignore

*/

define('SEARCH_RESULT_NOT_IN_CACHE', 0);

define('SEARCH_RESULT_IN_CACHE', 1);

define('SEARCH_RESULT_INCOMPLETE', 2);

/**

* search_backend

* optional base class for search plugins providing simple caching based on ACM

* and functions to retrieve ignore_words and synonyms

* @package search

*/

class search_backend

{

	var $ignore_words = array();

	var $match_synonym = array();

	var $replace_synonym = array();

	function search_backend(&$error)

	{

		// This class cannot be used as a search plugin

		$error = true;

	}

	/**

	* Retrieves a language dependend list of words that should be ignored by the search

	*/

	function get_ignore_words()

	{

		if (!sizeof($this->ignore_words))

		{

			global $user, $phpEx;

			$words = array();

			if (file_exists("{$user->lang_path}{$user->lang_name}/search_ignore_words.$phpEx"))

			{

				// include the file containing ignore words

				include("{$user->lang_path}{$user->lang_name}/search_ignore_words.$phpEx");

			}

			$this->ignore_words = $words;

			unset($words);

		}

	}

	/**

	* Stores a list of synonyms that should be replaced in $this->match_synonym and $this->replace_synonym and caches them

	*/

	function get_synonyms()

	{

		if (!sizeof($this->match_synonym))

		{

			global $user, $phpEx;

			$synonyms = array();

			if (file_exists("{$user->lang_path}{$user->lang_name}/search_synonyms.$phpEx"))

			{

				// include the file containing synonyms

				include("{$user->lang_path}{$user->lang_name}/search_synonyms.$phpEx");

			}

			$this->match_synonym = array_keys($synonyms);

			$this->replace_synonym = array_values($synonyms);

			unset($synonyms);

		}

	}

	/**

	* Retrieves cached search results

	*

	* @param int &$result_count will contain the number of all results for the search (not only for the current page)

	* @param array &$id_ary is filled with the ids belonging to the requested page that are stored in the cache

	*

	* @return int SEARCH_RESULT_NOT_IN_CACHE or SEARCH_RESULT_IN_CACHE or SEARCH_RESULT_INCOMPLETE

	*/

	function obtain_ids($search_key, &$result_count, &$id_ary, $start, $per_page, $sort_dir)

	{

		global $cache;

		if (!($stored_ids = $cache->get('_search_results_' . $search_key)))

		{

			// no search results cached for this search_key

			return SEARCH_RESULT_NOT_IN_CACHE;

		}

		else

		{

			$result_count = $stored_ids[-1];

			$reverse_ids = ($stored_ids[-2] != $sort_dir) ? true : false;

			$complete = true;

			// change the start to the actual end of the current request if the sort direction differs

			// from the dirction in the cache and reverse the ids later

			if ($reverse_ids)

			{

				$start = $result_count - $start - $per_page;

				// the user requested a page past the last index

				if ($start < 0)

				{

					return SEARCH_RESULT_NOT_IN_CACHE;

				}

			}

			for ($i = $start, $n = $start + $per_page; ($i < $n) && ($i < $result_count); $i++)

			{

				if (!isset($stored_ids[$i]))

				{

					$complete = false;

				}

				else

				{

					$id_ary[] = $stored_ids[$i];

				}

			}

			unset($stored_ids);

			if ($reverse_ids)

			{

				$id_ary = array_reverse($id_ary);

			}

			if (!$complete)

			{

				return SEARCH_RESULT_INCOMPLETE;

			}

			return SEARCH_RESULT_IN_CACHE;

		}

	}

	/**

	* Caches post/topic ids

	*

	* @param array &$id_ary contains a list of post or topic ids that shall be cached, the first element

	* 	must have the absolute index $start in the result set.

	*/

	function save_ids($search_key, $keywords, $author_ary, $result_count, &$id_ary, $start, $sort_dir)

	{

		global $cache, $config, $db, $user;

		$length = min(sizeof($id_ary), $config['search_block_size']);

		// nothing to cache so exit

		if (!$length)

		{

			return;

		}

		$store_ids = array_slice($id_ary, 0, $length);

		// create a new resultset if there is none for this search_key yet

		// or add the ids to the existing resultset

		if (!($store = $cache->get('_search_results_' . $search_key)))

		{

			// add the current keywords to the recent searches in the cache which are listed on the search page

			if (!empty($keywords) || sizeof($author_ary))

			{

				$sql = 'SELECT search_time

					FROM ' . SEARCH_RESULTS_TABLE . '

					WHERE search_key = \'' . $db->sql_escape($search_key) . '\'';

				$result = $db->sql_query($sql);

				if (!$db->sql_fetchrow($result))

				{

					$sql_ary = array(

						'search_key'		=> $search_key,

						'search_time'		=> time(),

						'search_keywords'	=> $keywords,

						'search_authors'	=> ' ' . implode(' ', $author_ary) . ' '

					);

					$sql = 'INSERT INTO ' . SEARCH_RESULTS_TABLE . ' ' . $db->sql_build_array('INSERT', $sql_ary);

					$db->sql_query($sql);

				}

				$db->sql_freeresult($result);

			}

			$sql = 'UPDATE ' . USERS_TABLE . '

				SET user_last_search = ' . time() . '

				WHERE user_id = ' . $user->data['user_id'];

			$db->sql_query($sql);

			$store = array(-1 => $result_count, -2 => $sort_dir);

			$id_range = range($start, $start + $length - 1);

		}

		else

		{

			// we use one set of results for both sort directions so we have to calculate the indizes

			// for the reversed array and we also have to reverse the ids themselves

			if ($store[-2] != $sort_dir)

			{

				$store_ids = array_reverse($store_ids);

				$id_range = range($store[-1] - $start - $length, $store[-1] - $start - 1);

			}

			else

			{

				$id_range = range($start, $start + $length - 1);

			}

		}

		$store_ids = array_combine($id_range, $store_ids);

		// append the ids

		if (is_array($store_ids))

		{

			$store += $store_ids;

			// if the cache is too big

			if (sizeof($store) - 2 > 20 * $config['search_block_size'])

			{

				// remove everything in front of two blocks in front of the current start index

				for ($i = 0, $n = $id_range[0] - 2 * $config['search_block_size']; $i < $n; $i++)

				{

					if (isset($store[$i]))

					{

						unset($store[$i]);

					}

				}

				// remove everything after two blocks after the current stop index

				end($id_range);

				for ($i = $store[-1] - 1, $n = current($id_range) + 2 * $config['search_block_size']; $i > $n; $i--)

				{

					if (isset($store[$i]))

					{

						unset($store[$i]);

					}

				}

			}

			$cache->put('_search_results_' . $search_key, $store, $config['search_store_results']);

			$sql = 'UPDATE ' . SEARCH_RESULTS_TABLE . '

				SET search_time = ' . time() . '

				WHERE search_key = \'' . $db->sql_escape($search_key) . '\'';

			$db->sql_query($sql);

		}

		unset($store);

		unset($store_ids);

		unset($id_range);

	}

	/**

	* Removes old entries from the search results table and removes searches with keywords that contain a word in $words.

	*/

	function destroy_cache($words, $authors = false)

	{

		global $db, $cache, $config;

		// clear all searches that searched for the specified words

		if (sizeof($words))

		{

			$sql_where = '';

			foreach ($words as $word)

			{

				$sql_where .= " OR search_keywords " . $db->sql_like_expression($db->any_char . $word . $db->any_char);

			}

			$sql = 'SELECT search_key

				FROM ' . SEARCH_RESULTS_TABLE . "

				WHERE search_keywords LIKE '%*%' $sql_where";

			$result = $db->sql_query($sql);

			while ($row = $db->sql_fetchrow($result))

			{

				$cache->destroy('_search_results_' . $row['search_key']);

			}

			$db->sql_freeresult($result);

		}

		// clear all searches that searched for the specified authors

		if (is_array($authors) && sizeof($authors))

		{

			$sql_where = '';

			foreach ($authors as $author)

			{

				$sql_where .= (($sql_where) ? ' OR ' : '') . 'search_authors LIKE \'% ' . (int) $author . ' %\'';

			}

			$sql = 'SELECT search_key

				FROM ' . SEARCH_RESULTS_TABLE . "

				WHERE $sql_where";

			$result = $db->sql_query($sql);

			while ($row = $db->sql_fetchrow($result))

			{

				$cache->destroy('_search_results_' . $row['search_key']);

			}

			$db->sql_freeresult($result);

		}

		$sql = 'DELETE

			FROM ' . SEARCH_RESULTS_TABLE . '

			WHERE search_time < ' . (time() - $config['search_store_results']);

		$db->sql_query($sql);

	}

}

?>