<?php
/**
*
* This file is part of the phpBB Forum Software package.
*
* @copyright (c) phpBB Limited <https://www.phpbb.com>
* @license GNU General Public License, version 2 (GPL-2.0)
*
* For full copyright and license information, please see
* the docs/CREDITS.txt file.
*
*/

namespace phpbb\search;

define('SPHINX_MAX_MATCHES', 20000);
define('SPHINX_CONNECT_RETRIES', 3);
define('SPHINX_CONNECT_WAIT_TIME', 300);

/**
* Fulltext search based on the sphinx search daemon
*/
class fulltext_sphinx
{
	/**
	 * Associative array holding index stats
	 * @var array
	 */
	protected $stats = array();

	/**
	 * Holds the words entered by user, obtained by splitting the entered query on whitespace
	 * @var array
	 */
	protected $split_words = array();

	/**
	 * Holds unique sphinx id
	 * @var string
	 */
	protected $id;

	/**
	 * Stores the names of both main and delta sphinx indexes
	 * separated by a semicolon
	 * @var string
	 */
	protected $indexes;

	/**
	 * Sphinx searchd client object
	 * @var SphinxClient
	 */
	protected $sphinx;

	/**
	 * Relative path to board root
	 * @var string
	 */
	protected $phpbb_root_path;

	/**
	 * PHP Extension
	 * @var string
	 */
	protected $php_ext;

	/**
	 * Auth object
	 * @var \phpbb\auth\auth
	 */
	protected $auth;

	/**
	 * Config object
	 * @var \phpbb\config\config
	 */
	protected $config;

	/**
	 * Database connection
	 * @var \phpbb\db\driver\driver_interface
	 */
	protected $db;

	/**
	 * Database Tools object
	 * @var \phpbb\db\tools\tools_interface
	 */
	protected $db_tools;

	/**
	 * Stores the database type if supported by sphinx
	 * @var string
	 */
	protected $dbtype;

	/**
	 * phpBB event dispatcher object
	 * @var \phpbb\event\dispatcher_interface
	 */
	protected $phpbb_dispatcher;

	/**
	 * User object
	 * @var \phpbb\user
	 */
	protected $user;

	/**
	 * Stores the generated content of the sphinx config file
	 * @var string
	 */
	protected $config_file_data = '';

	/**
	 * Contains tidied search query.
	 * Operators are prefixed in search query and common words excluded
	 * @var string
	 */
	protected $search_query;

	/**
	 * Constructor
	 * Creates a new \phpbb\search\fulltext_postgres, which is used as a search backend
	 *
	 * @param string|bool $error Any error that occurs is passed on through this reference variable otherwise false
	 * @param string $phpbb_root_path Relative path to phpBB root
	 * @param string $phpEx PHP file extension
	 * @param \phpbb\auth\auth $auth Auth object
	 * @param \phpbb\config\config $config Config object
	 * @param \phpbb\db\driver\driver_interface $db Database object
	 * @param \phpbb\user $user User object
	 * @param \phpbb\event\dispatcher_interface	$phpbb_dispatcher	Event dispatcher object
	 */
	public function __construct(&$error, $phpbb_root_path, $phpEx, $auth, $config, $db, $user, $phpbb_dispatcher)
	{
		$this->phpbb_root_path = $phpbb_root_path;
		$this->php_ext = $phpEx;
		$this->config = $config;
		$this->phpbb_dispatcher = $phpbb_dispatcher;
		$this->user = $user;
		$this->db = $db;
		$this->auth = $auth;

		// Initialize \phpbb\db\tools\tools object
		global $phpbb_container; // TODO inject into object
		$this->db_tools = $phpbb_container->get('dbal.tools');

		if (!$this->config['fulltext_sphinx_id'])
		{
			$this->config->set('fulltext_sphinx_id', unique_id());
		}
		$this->id = $this->config['fulltext_sphinx_id'];
		$this->indexes = 'index_phpbb_' . $this->id . '_delta;index_phpbb_' . $this->id . '_main';

		if (!class_exists('SphinxClient'))
		{
			require($this->phpbb_root_path . 'includes/sphinxapi.' . $this->php_ext);
		}

		// Initialize sphinx client
		$this->sphinx = new \SphinxClient();

		$this->sphinx->SetServer(($this->config['fulltext_sphinx_host'] ? $this->config['fulltext_sphinx_host'] : 'localhost'), ($this->config['fulltext_sphinx_port'] ? (int) $this->config['fulltext_sphinx_port'] : 9312));

		$error = false;
	}

	/**
	* Returns the name of this search backend to be displayed to administrators
	*
	* @return string Name
	*/
	public function get_name()
	{
		return 'Sphinx Fulltext';
	}

	/**
	 * Returns the search_query
	 *
	 * @return string search query
	 */
	public function get_search_query()
	{
		return $this->search_query;
	}

	/**
	 * Returns false as there is no word_len array
	 *
	 * @return false
	 */
	public function get_word_length()
	{
		return false;
	}

	/**
	 * Returns an empty array as there are no common_words
	 *
	 * @return array common words that are ignored by search backend
	 */
	public function get_common_words()
	{
		return array();
	}

	/**
	* Checks permissions and paths, if everything is correct it generates the config file
	*
	* @return string|bool Language key of the error/incompatibility encountered, or false if successful
	*/
	public function init()
	{
		if ($this->db->get_sql_layer() != 'mysqli' && $this->db->get_sql_layer() != 'postgres')
		{
			return $this->user->lang['FULLTEXT_SPHINX_WRONG_DATABASE'];
		}

		// Move delta to main index each hour
		$this->config->set('search_gc', 3600);

		return false;
	}

	/**
	 * Generates content of sphinx.conf
	 *
	 * @return bool True if sphinx.conf content is correctly generated, false otherwise
	 */
	protected function config_generate()
	{
		// Check if Database is supported by Sphinx
		if ($this->db->get_sql_layer() == 'mysqli')
		{
			$this->dbtype = 'mysql';
		}
		else if ($this->db->get_sql_layer() == 'postgres')
		{
			$this->dbtype = 'pgsql';
		}
		else
		{
			$this->config_file_data = $this->user->lang('FULLTEXT_SPHINX_WRONG_DATABASE');
			return false;
		}

		// Check if directory paths have been filled
		if (!$this->config['fulltext_sphinx_data_path'])
		{
			$this->config_file_data = $this->user->lang('FULLTEXT_SPHINX_NO_CONFIG_DATA');
			return false;
		}

		include($this->phpbb_root_path . 'config.' . $this->php_ext);

		/* Now that we're sure everything was entered correctly,
		generate a config for the index. We use a config value
		fulltext_sphinx_id for this, as it should be unique. */
		$config_object = new \phpbb\search\sphinx\config($this->config_file_data);
		$config_data = array(
			'source source_phpbb_' . $this->id . '_main' => array(
				array('type',						$this->dbtype . ' # mysql or pgsql'),
				// This config value sql_host needs to be changed incase sphinx and sql are on different servers
				array('sql_host',					$dbhost . ' # SQL server host sphinx connects to'),
				array('sql_user',					'[dbuser]'),
				array('sql_pass',					'[dbpassword]'),
				array('sql_db',						$dbname),
				array('sql_port',					$dbport . ' # optional, default is 3306 for mysql and 5432 for pgsql'),
				array('sql_query_pre',				'SET NAMES \'utf8\''),
				array('sql_query_pre',				'UPDATE ' . SPHINX_TABLE . ' SET max_doc_id = (SELECT MAX(post_id) FROM ' . POSTS_TABLE . ') WHERE counter_id = 1'),
				array('sql_query_range',			'SELECT MIN(post_id), MAX(post_id) FROM ' . POSTS_TABLE . ''),
				array('sql_range_step',				'5000'),
				array('sql_query',					'SELECT
						p.post_id AS id,
						p.forum_id,
						p.topic_id,
						p.poster_id,
						p.post_visibility,
						CASE WHEN p.post_id = t.topic_first_post_id THEN 1 ELSE 0 END as topic_first_post,
						p.post_time,
						p.post_subject,
						p.post_subject as title,
						p.post_text as data,
						t.topic_last_post_time,
						0 as deleted
					FROM ' . POSTS_TABLE . ' p, ' . TOPICS_TABLE . ' t
					WHERE
						p.topic_id = t.topic_id
						AND p.post_id >= $start AND p.post_id <= $end'),
				array('sql_query_post',				''),
				array('sql_query_post_index',		'UPDATE ' . SPHINX_TABLE . ' SET max_doc_id = $maxid WHERE counter_id = 1'),
				array('sql_attr_uint',				'forum_id'),
				array('sql_attr_uint',				'topic_id'),
				array('sql_attr_uint',				'poster_id'),
				array('sql_attr_uint',				'post_visibility'),
				array('sql_attr_bool',				'topic_first_post'),
				array('sql_attr_bool',				'deleted'),
				array('sql_attr_timestamp',			'post_time'),
				array('sql_attr_timestamp',			'topic_last_post_time'),
				array('sql_attr_string',			'post_subject'),
			),
			'source source_phpbb_' . $this->id . '_delta : source_phpbb_' . $this->id . '_main' => array(
				array('sql_query_pre',				'SET NAMES \'utf8\''),
				array('sql_query_range',			''),
				array('sql_range_step',				''),
				array('sql_query',					'SELECT
						p.post_id AS id,
						p.forum_id,
						p.topic_id,
						p.poster_id,
						p.post_visibility,
						CASE WHEN p.post_id = t.topic_first_post_id THEN 1 ELSE 0 END as topic_first_post,
						p.post_time,
						p.post_subject,
						p.post_subject as title,
						p.post_text as data,
						t.topic_last_post_time,
						0 as deleted
					FROM ' . POSTS_TABLE . ' p, ' . TOPICS_TABLE . ' t
					WHERE
						p.topic_id = t.topic_id
						AND p.post_id >=  ( SELECT max_doc_id FROM ' . SPHINX_TABLE . ' WHERE counter_id=1 )'),
				array('sql_query_post_index',		''),
			),
			'index index_phpbb_' . $this->id . '_main' => array(
				array('path',						$this->config['fulltext_sphinx_data_path'] . 'index_phpbb_' . $this->id . '_main'),
				array('source',						'source_phpbb_' . $this->id . '_main'),
				array('docinfo',					'extern'),
				array('morphology',					'none'),
				array('stopwords',					''),
				array('wordforms',					'  # optional, specify path to wordforms file. See ./docs/sphinx_wordforms.txt for example'),
				array('exceptions',					'  # optional, specify path to exceptions file. See ./docs/sphinx_exceptions.txt for example'),
				array('min_word_len',				'2'),
				array('charset_table',				'U+FF10..U+FF19->0..9, 0..9, U+FF41..U+FF5A->a..z, U+FF21..U+FF3A->a..z, A..Z->a..z, a..z, U+0149, U+017F, U+0138, U+00DF, U+00FF, U+00C0..U+00D6->U+00E0..U+00F6, U+00E0..U+00F6, U+00D8..U+00DE->U+00F8..U+00FE, U+00F8..U+00FE, U+0100->U+0101, U+0101, U+0102->U+0103, U+0103, U+0104->U+0105, U+0105, U+0106->U+0107, U+0107, U+0108->U+0109, U+0109, U+010A->U+010B, U+010B, U+010C->U+010D, U+010D, U+010E->U+010F, U+010F, U+0110->U+0111, U+0111, U+0112->U+0113, U+0113, U+0114->U+0115, U+0115, U+0116->U+0117, U+0117, U+0118->U+0119, U+0119, U+011A->U+011B, U+011B, U+011C->U+011D, U+011D, U+011E->U+011F, U+011F, U+0130->U+0131, U+0131, U+0132->U+0133, U+0133, U+0134->U+0135, U+0135, U+0136->U+0137, U+0137, U+0139->U+013A, U+013A, U+013B->U+013C, U+013C, U+013D->U+013E, U+013E, U+013F->U+0140, U+0140, U+0141->U+0142, U+0142, U+0143->U+0144, U+0144, U+0145->U+0146, U+0146, U+0147->U+0148, U+0148, U+014A->U+014B, U+014B, U+014C->U+014D, U+014D, U+014E->U+014F, U+014F, U+0150->U+0151, U+0151, U+0152->U+0153, U+0153, U+0154->U+0155, U+0155, U+0156->U+0157, U+0157, U+0158->U+0159, U+0159, U+015A->U+015B, U+015B, U+015C->U+015D, U+015D, U+015E->U+015F, U+015F, U+0160->U+0161, U+0161, U+0162->U+0163, U+0163, U+0164->U+0165, U+0165, U+0166->U+0167, U+0167, U+0168->U+0169, U+0169, U+016A->U+016B, U+016B, U+016C->U+016D, U+016D, U+016E->U+016F, U+016F, U+0170->U+0171, U+0171, U+0172->U+0173, U+0173, U+0174->U+0175, U+0175, U+0176->U+0177, U+0177, U+0178->U+00FF, U+00FF, U+0179->U+017A, U+017A, U+017B->U+017C, U+017C, U+017D->U+017E, U+017E, U+0410..U+042F->U+0430..U+044F, U+0430..U+044F, U+4E00..U+9FFF'),
				array('ignore_chars', 				'U+0027, U+002C'),
				array('min_prefix_len',				'3 # Minimum number of characters for wildcard searches by prefix (min 1). Default is 3. If specified, set min_infix_len to 0'),
				array('min_infix_len',				'0 # Minimum number of characters for wildcard searches by infix (min 2). If specified, set min_prefix_len to 0'),
				array('html_strip',					'1'),
				array('index_exact_words',			'0 # Set to 1 to enable exact search operator. Requires wordforms or morphology'),
				array('blend_chars', 				'U+23, U+24, U+25, U+26, U+40'),
			),
			'index index_phpbb_' . $this->id . '_delta : index_phpbb_' . $this->id . '_main' => array(
				array('path',						$this->config['fulltext_sphinx_data_path'] . 'index_phpbb_' . $this->id . '_delta'),
				array('source',						'source_phpbb_' . $this->id . '_delta'),
			),
			'indexer' => array(
				array('mem_limit',					$this->config['fulltext_sphinx_indexer_mem_limit'] . 'M'),
			),
			'searchd' => array(
				array('listen'	,					($this->config['fulltext_sphinx_host'] ? $this->config['fulltext_sphinx_host'] : 'localhost') . ':' . ($this->config['fulltext_sphinx_port'] ? $this->config['fulltext_sphinx_port'] : '9312')),
				array('log',						$this->config['fulltext_sphinx_data_path'] . 'log/searchd.log'),
				array('query_log',					$this->config['fulltext_sphinx_data_path'] . 'log/sphinx-query.log'),
				array('read_timeout',				'5'),
				array('max_children',				'30'),
				array('pid_file',					$this->config['fulltext_sphinx_data_path'] . 'searchd.pid'),
				array('binlog_path',				$this->config['fulltext_sphinx_data_path']),
			),
		);

		$non_unique = array('sql_query_pre' => true, 'sql_attr_uint' => true, 'sql_attr_timestamp' => true, 'sql_attr_str2ordinal' => true, 'sql_attr_bool' => true);
		$delete = array('sql_group_column' => true, 'sql_date_column' => true, 'sql_str2ordinal_column' => true);

		/**
		* Allow adding/changing the Sphinx configuration data
		*
		* @event core.search_sphinx_modify_config_data
		* @var	array	config_data	Array with the Sphinx configuration data
		* @var	array	non_unique	Array with the Sphinx non-unique variables to delete
		* @var	array	delete		Array with the Sphinx variables to delete
		* @since 3.1.7-RC1
		*/
		$vars = array(
			'config_data',
			'non_unique',
			'delete',
		);
		extract($this->phpbb_dispatcher->trigger_event('core.search_sphinx_modify_config_data', compact($vars)));

		foreach ($config_data as $section_name => $section_data)
		{
			$section = $config_object->get_section_by_name($section_name);
			if (!$section)
			{
				$section = $config_object->add_section($section_name);
			}

			foreach ($delete as $key => $void)
			{
				$section->delete_variables_by_name($key);
			}

			foreach ($non_unique as $key => $void)
			{
				$section->delete_variables_by_name($key);
			}

			foreach ($section_data as $entry)
			{
				$key = $entry[0];
				$value = $entry[1];

				if (!isset($non_unique[$key]))
				{
					$variable = $section->get_variable_by_name($key);
					if (!$variable)
					{
						$section->create_variable($key, $value);
					}
					else
					{
						$variable->set_value($value);
					}
				}
				else
				{
					$section->create_variable($key, $value);
				}
			}
		}
		$this->config_file_data = $config_object->get_data();

		return true;
	}

	/**
	* Splits keywords entered by a user into an array of words stored in $this->split_words
	* Stores the tidied search query in $this->search_query
	*
	* @param string $keywords Contains the keyword as entered by the user
	* @param string $terms is either 'all' or 'any'
	* @return false if no valid keywords were found and otherwise true
	*/
	public function split_keywords(&$keywords, $terms)
	{
		// Keep quotes and new lines
		$keywords = str_replace(['&quot;', "\n"], ['"', ' '], trim($keywords));

		if ($terms == 'all')
		{
			// Replaces verbal operators OR and NOT with special characters | and -, unless appearing within quotation marks
			$match		= ['#\sor\s(?=([^"]*"[^"]*")*[^"]*$)#i', '#\snot\s(?=([^"]*"[^"]*")*[^"]*$)#i'];
			$replace	= [' | ', ' -'];

			$keywords = preg_replace($match, $replace, $keywords);
			$this->sphinx->SetMatchMode(SPH_MATCH_EXTENDED);
		}
		else
		{
			$match = ['\\', '(',')', '|', '!', '@', '~', '/', '^', '$', '=', '&amp;', '&lt;', '&gt;'];

			$keywords = str_replace($match, ' ', $keywords);
			$this->sphinx->SetMatchMode(SPH_MATCH_ANY);
		}

		if (strlen($keywords) > 0)
		{
			$this->search_query = str_replace('"', '&quot;', $keywords);
			return true;
		}

		return false;
	}

	/**
	* Cleans search query passed into Sphinx search engine, as follows:
	* 1. Hyphenated words are replaced with keyword search for either the exact phrase with spaces
	*    or as a single word without spaces eg search for "know-it-all" becomes ("know it all"|"knowitall*")
	* 2. Words with apostrophes are contracted eg "it's" becomes "its"
	* 3. <, >, " and & are decoded from HTML entities.
	* 4. Following special characters used as search operators in Sphinx are preserved when used with correct syntax:
	*    (a) quorum matching: "the world is a wonderful place"/3
	*        Finds 3 of the words within the phrase. Number must be between 1 and 9.
	*    (b) proximity search: "hello world"~10
	*        Finds hello and world within 10 words of each other. Number can be between 1 and 99.
	*    (c) strict word order: aaa << bbb << ccc
	*        Finds "aaa" only where it appears before "bbb" and only where "bbb" appears before "ccc".
	*    (d) exact match operator: if lemmatizer or stemming enabled,
	*        search will find exact match only and ignore other grammatical forms of the same word stem.
	*        eg. raining =cats and =dogs
	*            will not return "raining cat and dog"
	*        eg. ="search this exact phrase"
	*            will not return "searched this exact phrase", "searching these exact phrases".
	* 5. Special characters /, ~, << and = not complying with the correct syntax
	*    and other reserved operators are escaped and searched literally.
	*    Special characters not explicitly listed in charset_table or blend_chars in sphinx.conf
	*    will not be indexed and keywords containing them will be ignored by Sphinx.
	*    By default, only $, %, & and @ characters are indexed and searchable.
	*    String transformation is in backend only and not visible to the end user
	*    nor reflected in the results page URL or keyword highlighting.
	*
	* @param string	$search_string
	* @return string
	*/
	public function sphinx_clean_search_string($search_string)
	{
		$from = ['@', '^', '$', '!', '&lt;', '&gt;', '&quot;', '&amp;', '\''];
		$to = ['\@', '\^', '\$', '\!', '<', '>', '"', '&', ''];

		$search_string = str_replace($from, $to, $search_string);

		$search_string = strrev($search_string);
		$search_string = preg_replace(['#\/(?!"[^"]+")#', '#~(?!"[^"]+")#'], ['/\\', '~\\'], $search_string);
		$search_string = strrev($search_string);

		$match = ['#(/|\\\\/)(?![1-9](\s|$))#', '#(~|\\\\~)(?!\d{1,2}(\s|$))#', '#((?:\p{L}|\p{N})+)-((?:\p{L}|\p{N})+)(?:-((?:\p{L}|\p{N})+))?(?:-((?:\p{L}|\p{N})+))?#i', '#<<\s*$#', '#(\S\K=|=(?=\s)|=$)#'];
		$replace = ['\/', '\~', '("$1 $2 $3 $4"|$1$2$3$4*)', '\<\<', '\='];

		$search_string = preg_replace($match, $replace, $search_string);
		$search_string = preg_replace('#\s+"\|#', '"|', $search_string);

		/**
		* OPTIONAL: Thousands separator stripped from numbers, eg search for '90,000' is queried as '90000'.
		* By default commas are stripped from search index so that '90,000' is indexed as '90000'
		*/
		// $search_string = preg_replace('#[0-9]{1,3}\K,(?=[0-9]{3})#', '', $search_string);

		return $search_string;
	}

	/**
	* Performs a search on keywords depending on display specific params. You have to run split_keywords() first
	*
	* @param	string		$type				contains either posts or topics depending on what should be searched for
	* @param	string		$fields				contains either titleonly (topic titles should be searched), msgonly (only message bodies should be searched), firstpost (only subject and body of the first post should be searched) or all (all post bodies and subjects should be searched)
	* @param	string		$terms				is either 'all' (use query as entered, words without prefix should default to "have to be in field") or 'any' (ignore search query parts and just return all posts that contain any of the specified words)
	* @param	array		$sort_by_sql		contains SQL code for the ORDER BY part of a query
	* @param	string		$sort_key			is the key of $sort_by_sql for the selected sorting
	* @param	string		$sort_dir			is either a or d representing ASC and DESC
	* @param	string		$sort_days			specifies the maximum amount of days a post may be old
	* @param	array		$ex_fid_ary			specifies an array of forum ids which should not be searched
	* @param	string		$post_visibility	specifies which types of posts the user can view in which forums
	* @param	int			$topic_id			is set to 0 or a topic id, if it is not 0 then only posts in this topic should be searched
	* @param	array		$author_ary			an array of author ids if the author should be ignored during the search the array is empty
	* @param	string		$author_name		specifies the author match, when ANONYMOUS is also a search-match
	* @param	array		&$id_ary			passed by reference, to be filled with ids for the page specified by $start and $per_page, should be ordered
	* @param	int			$start				indicates the first index of the page
	* @param	int			$per_page			number of ids each page is supposed to contain
	* @return	boolean|int						total number of results
	*/
	public function keyword_search($type, $fields, $terms, $sort_by_sql, $sort_key, $sort_dir, $sort_days, $ex_fid_ary, $post_visibility, $topic_id, $author_ary, $author_name, &$id_ary, &$start, $per_page)
	{
		global $user, $phpbb_log;

		// No keywords? No posts.
		if (!strlen($this->search_query) && !count($author_ary))
		{
			return false;
		}

		$id_ary = array();

		// Sorting

		if ($type == 'topics')
		{
			switch ($sort_key)
			{
				case 'a':
					$this->sphinx->SetGroupBy('topic_id', SPH_GROUPBY_ATTR, 'poster_id ' . (($sort_dir == 'a') ? 'ASC' : 'DESC'));
				break;

				case 'f':
					$this->sphinx->SetGroupBy('topic_id', SPH_GROUPBY_ATTR, 'forum_id ' . (($sort_dir == 'a') ? 'ASC' : 'DESC'));
				break;

				case 'i':

				case 's':
					$this->sphinx->SetGroupBy('topic_id', SPH_GROUPBY_ATTR, 'post_subject ' . (($sort_dir == 'a') ? 'ASC' : 'DESC'));
				break;

				case 't':

				default:
					$this->sphinx->SetGroupBy('topic_id', SPH_GROUPBY_ATTR, 'topic_last_post_time ' . (($sort_dir == 'a') ? 'ASC' : 'DESC'));
				break;
			}
		}
		else
		{
			switch ($sort_key)
			{
				case 'a':
					$this->sphinx->SetSortMode(($sort_dir == 'a') ? SPH_SORT_ATTR_ASC : SPH_SORT_ATTR_DESC, 'poster_id');
				break;

				case 'f':
					$this->sphinx->SetSortMode(($sort_dir == 'a') ? SPH_SORT_ATTR_ASC : SPH_SORT_ATTR_DESC, 'forum_id');
				break;

				case 'i':

				case 's':
					$this->sphinx->SetSortMode(($sort_dir == 'a') ? SPH_SORT_ATTR_ASC : SPH_SORT_ATTR_DESC, 'post_subject');
				break;

				case 't':

				default:
					$this->sphinx->SetSortMode(($sort_dir == 'a') ? SPH_SORT_ATTR_ASC : SPH_SORT_ATTR_DESC, 'post_time');
				break;
			}
		}

		// Most narrow filters first
		if ($topic_id)
		{
			$this->sphinx->SetFilter('topic_id', array($topic_id));
		}

		/**
		* Allow modifying the Sphinx search options
		*
		* @event core.search_sphinx_keywords_modify_options
		* @var	string	type				Searching type ('posts', 'topics')
		* @var	string	fields				Searching fields ('titleonly', 'msgonly', 'firstpost', 'all')
		* @var	string	terms				Searching terms ('all', 'any')
		* @var	int		sort_days			Time, in days, of the oldest possible post to list
		* @var	string	sort_key			The sort type used from the possible sort types
		* @var	int		topic_id			Limit the search to this topic_id only
		* @var	array	ex_fid_ary			Which forums not to search on
		* @var	string	post_visibility		Post visibility data
		* @var	array	author_ary			Array of user_id containing the users to filter the results to
		* @var	string	author_name			The username to search on
		* @var	object	sphinx				The Sphinx searchd client object
		* @since 3.1.7-RC1
		*/
		$sphinx = $this->sphinx;
		$vars = array(
			'type',
			'fields',
			'terms',
			'sort_days',
			'sort_key',
			'topic_id',
			'ex_fid_ary',
			'post_visibility',
			'author_ary',
			'author_name',
			'sphinx',
		);
		extract($this->phpbb_dispatcher->trigger_event('core.search_sphinx_keywords_modify_options', compact($vars)));
		$this->sphinx = $sphinx;
		unset($sphinx);

		$search_query_prefix = '';

		switch ($fields)
		{
			case 'titleonly':
				// Only search the title
				if ($terms == 'all')
				{
					$search_query_prefix = '@title ';
				}
				// Weight for the title
				$this->sphinx->SetFieldWeights(array("title" => 5, "data" => 1));
				// 1 is first_post, 0 is not first post
				$this->sphinx->SetFilter('topic_first_post', array(1));
			break;

			case 'msgonly':
				// Only search the body
				if ($terms == 'all')
				{
					$search_query_prefix = '@data ';
				}
				// Weight for the body
				$this->sphinx->SetFieldWeights(array("title" => 1, "data" => 5));
			break;

			case 'firstpost':
				// More relative weight for the title, also search the body
				$this->sphinx->SetFieldWeights(array("title" => 5, "data" => 1));
				// 1 is first_post, 0 is not first post
				$this->sphinx->SetFilter('topic_first_post', array(1));
			break;

			default:
				// More relative weight for the title, also search the body
				$this->sphinx->SetFieldWeights(array("title" => 5, "data" => 1));
			break;
		}

		if (count($author_ary))
		{
			$this->sphinx->SetFilter('poster_id', $author_ary);
		}

		// As this is not simply possible at the moment, we limit the result to approved posts.
		// This will make it impossible for moderators to search unapproved and softdeleted posts,
		// but at least it will also cause the same for normal users.
		$this->sphinx->SetFilter('post_visibility', array(ITEM_APPROVED));

		if (count($ex_fid_ary))
		{
			// All forums that a user is allowed to access
			$fid_ary = array_unique(array_intersect(array_keys($this->auth->acl_getf('f_read', true)), array_keys($this->auth->acl_getf('f_search', true))));
			// All forums that the user wants to and can search in
			$search_forums = array_diff($fid_ary, $ex_fid_ary);

			if (count($search_forums))
			{
				$this->sphinx->SetFilter('forum_id', $search_forums);
			}
		}

		$this->sphinx->SetFilter('deleted', array(0));

		$this->sphinx->SetLimits((int) $start, (int) $per_page, max(SPHINX_MAX_MATCHES, (int) $start + $per_page));
		$result = $this->sphinx->Query($search_query_prefix . $this->sphinx_clean_search_string(str_replace('&quot;', '"', $this->search_query)), $this->indexes);

		// Could be connection to localhost:9312 failed (errno=111,
		// msg=Connection refused) during rotate, retry if so
		$retries = SPHINX_CONNECT_RETRIES;
		while (!$result && (strpos($this->sphinx->GetLastError(), "errno=111,") !== false) && $retries--)
		{
			usleep(SPHINX_CONNECT_WAIT_TIME);
			$result = $this->sphinx->Query($search_query_prefix . $this->sphinx_clean_search_string(str_replace('&quot;', '"', $this->search_query)), $this->indexes);
		}

		if ($this->sphinx->GetLastError())
		{
			$phpbb_log->add('critical', $user->data['user_id'], $user->ip, 'LOG_SPHINX_ERROR', false, array($this->sphinx->GetLastError()));
			if ($this->auth->acl_get('a_'))
			{
				trigger_error($this->user->lang('SPHINX_SEARCH_FAILED', $this->sphinx->GetLastError()));
			}
			else
			{
				trigger_error($this->user->lang('SPHINX_SEARCH_FAILED_LOG'));
			}
		}

		$result_count = $result['total_found'];

		if ($result_count && $start >= $result_count)
		{
			$start = floor(($result_count - 1) / $per_page) * $per_page;

			$this->sphinx->SetLimits((int) $start, (int) $per_page, max(SPHINX_MAX_MATCHES, (int) $start + $per_page));
			$result = $this->sphinx->Query($search_query_prefix . $this->sphinx_clean_search_string(str_replace('&quot;', '"', $this->search_query)), $this->indexes);

			// Could be connection to localhost:9312 failed (errno=111,
			// msg=Connection refused) during rotate, retry if so
			$retries = SPHINX_CONNECT_RETRIES;
			while (!$result && (strpos($this->sphinx->GetLastError(), "errno=111,") !== false) && $retries--)
			{
				usleep(SPHINX_CONNECT_WAIT_TIME);
				$result = $this->sphinx->Query($search_query_prefix . $this->sphinx_clean_search_string(str_replace('&quot;', '"', $this->search_query)), $this->indexes);
			}
		}

		$id_ary = array();
		if (isset($result['matches']))
		{
			if ($type == 'posts')
			{
				$id_ary = array_keys($result['matches']);
			}
			else
			{
				foreach ($result['matches'] as $key => $value)
				{
					$id_ary[] = $value['attrs']['topic_id'];
				}
			}
		}
		else
		{
			return false;
		}

		$id_ary = array_slice($id_ary, 0, (int) $per_page);

		return $result_count;
	}

	/**
	* Performs a search on an author's posts without caring about message contents. Depends on display specific params
	*
	* @param	string		$type				contains either posts or topics depending on what should be searched for
	* @param	boolean		$firstpost_only		if true, only topic starting posts will be considered
	* @param	array		$sort_by_sql		contains SQL code for the ORDER BY part of a query
	* @param	string		$sort_key			is the key of $sort_by_sql for the selected sorting
	* @param	string		$sort_dir			is either a or d representing ASC and DESC
	* @param	string		$sort_days			specifies the maximum amount of days a post may be old
	* @param	array		$ex_fid_ary			specifies an array of forum ids which should not be searched
	* @param	string		$post_visibility	specifies which types of posts the user can view in which forums
	* @param	int			$topic_id			is set to 0 or a topic id, if it is not 0 then only posts in this topic should be searched
	* @param	array		$author_ary			an array of author ids
	* @param	string		$author_name		specifies the author match, when ANONYMOUS is also a search-match
	* @param	array		&$id_ary			passed by reference, to be filled with ids for the page specified by $start and $per_page, should be ordered
	* @param	int			$start				indicates the first index of the page
	* @param	int			$per_page			number of ids each page is supposed to contain
	* @return	boolean|int						total number of results
	*/
	public function author_search($type, $firstpost_only, $sort_by_sql, $sort_key, $sort_dir, $sort_days, $ex_fid_ary, $post_visibility, $topic_id, $author_ary, $author_name, &$id_ary, $start, $per_page)
	{
		$this->search_query = '';

		$this->sphinx->SetMatchMode(SPH_MATCH_FULLSCAN);
		$fields = ($firstpost_only) ? 'firstpost' : 'all';
		$terms = 'all';
		return $this->keyword_search($type, $fields, $terms, $sort_by_sql, $sort_key, $sort_dir, $sort_days, $ex_fid_ary, $post_visibility, $topic_id, $author_ary, $author_name, $id_ary, $start, $per_page);
	}

	/**
	 * Updates wordlist and wordmatch tables when a message is posted or changed
	 *
	 * @param	string	$mode	Contains the post mode: edit, post, reply, quote
	 * @param	int	$post_id	The id of the post which is modified/created
	 * @param	string	&$message	New or updated post content
	 * @param	string	&$subject	New or updated post subject
	 * @param	int	$poster_id	Post author's user id
	 * @param	int	$forum_id	The id of the forum in which the post is located
	 */
	public function index($mode, $post_id, &$message, &$subject, $poster_id, $forum_id)
	{
		/**
		* Event to modify method arguments before the Sphinx search index is updated
		*
		* @event core.search_sphinx_index_before
		* @var string	mode				Contains the post mode: edit, post, reply, quote
		* @var int		post_id				The id of the post which is modified/created
		* @var string	message				New or updated post content
		* @var string	subject				New or updated post subject
		* @var int		poster_id			Post author's user id
		* @var int		forum_id			The id of the forum in which the post is located
		* @since 3.2.3-RC1
		*/
		$vars = array(
			'mode',
			'post_id',
			'message',
			'subject',
			'poster_id',
			'forum_id',
		);
		extract($this->phpbb_dispatcher->trigger_event('core.search_sphinx_index_before', compact($vars)));

		if ($mode == 'edit')
		{
			$this->sphinx->UpdateAttributes($this->indexes, array('forum_id', 'poster_id'), array((int) $post_id => array((int) $forum_id, (int) $poster_id)));
		}
		else if ($mode != 'post' && $post_id)
		{
			// Update topic_last_post_time for full topic
			$sql_array = array(
				'SELECT'	=> 'p1.post_id',
				'FROM'		=> array(
					POSTS_TABLE	=> 'p1',
				),
				'LEFT_JOIN'	=> array(array(
					'FROM'	=> array(
						POSTS_TABLE	=> 'p2'
					),
					'ON'	=> 'p1.topic_id = p2.topic_id',
				)),
				'WHERE' => 'p2.post_id = ' . ((int) $post_id),
			);

			$sql = $this->db->sql_build_query('SELECT', $sql_array);
			$result = $this->db->sql_query($sql);

			$post_updates = array();
			$post_time = time();
			while ($row = $this->db->sql_fetchrow($result))
			{
				$post_updates[(int) $row['post_id']] = array($post_time);
			}
			$this->db->sql_freeresult($result);

			if (count($post_updates))
			{
				$this->sphinx->UpdateAttributes($this->indexes, array('topic_last_post_time'), $post_updates);
			}
		}
	}

	/**
	* Delete a post from the index after it was deleted
	*/
	public function index_remove($post_ids, $author_ids, $forum_ids)
	{
		$values = array();
		foreach ($post_ids as $post_id)
		{
			$values[$post_id] = array(1);
		}

		$this->sphinx->UpdateAttributes($this->indexes, array('deleted'), $values);
	}

	/**
	* Nothing needs to be destroyed
	*/
	public function tidy($create = false)
	{
		$this->config->set('search_last_gc', time(), false);
	}

	/**
	* Create sphinx table
	*
	* @return string|bool error string is returned incase of errors otherwise false
	*/
	public function create_index($acp_module, $u_action)
	{
		if (!$this->index_created())
		{
			$table_data = array(
				'COLUMNS'	=> array(
					'counter_id'	=> array('UINT', 0),
					'max_doc_id'	=> array('UINT', 0),
				),
				'PRIMARY_KEY'	=> 'counter_id',
			);
			$this->db_tools->sql_create_table(SPHINX_TABLE, $table_data);

			$sql = 'TRUNCATE TABLE ' . SPHINX_TABLE;
			$this->db->sql_query($sql);

			$data = array(
				'counter_id'	=> '1',
				'max_doc_id'	=> '0',
			);
			$sql = 'INSERT INTO ' . SPHINX_TABLE . ' ' . $this->db->sql_build_array('INSERT', $data);
			$this->db->sql_query($sql);
		}

		return false;
	}

	/**
	* Drop sphinx table
	*
	* @return string|bool error string is returned incase of errors otherwise false
	*/
	public function delete_index($acp_module, $u_action)
	{
		if (!$this->index_created())
		{
			return false;
		}

		$this->db_tools->sql_table_drop(SPHINX_TABLE);

		return false;
	}

	/**
	* Returns true if the sphinx table was created
	*
	* @return bool true if sphinx table was created
	*/
	public function index_created($allow_new_files = true)
	{
		$created = false;

		if ($this->db_tools->sql_table_exists(SPHINX_TABLE))
		{
			$created = true;
		}

		return $created;
	}

	/**
	* Returns an associative array containing information about the indexes
	*
	* @return string|bool Language string of error false otherwise
	*/
	public function index_stats()
	{
		if (empty($this->stats))
		{
			$this->get_stats();
		}

		return array(
			$this->user->lang['FULLTEXT_SPHINX_MAIN_POSTS']			=> ($this->index_created()) ? $this->stats['main_posts'] : 0,
			$this->user->lang['FULLTEXT_SPHINX_DELTA_POSTS']			=> ($this->index_created()) ? $this->stats['total_posts'] - $this->stats['main_posts'] : 0,
			$this->user->lang['FULLTEXT_MYSQL_TOTAL_POSTS']			=> ($this->index_created()) ? $this->stats['total_posts'] : 0,
		);
	}

	/**
	* Collects stats that can be displayed on the index maintenance page
	*/
	protected function get_stats()
	{
		if ($this->index_created())
		{
			$sql = 'SELECT COUNT(post_id) as total_posts
				FROM ' . POSTS_TABLE;
			$result = $this->db->sql_query($sql);
			$this->stats['total_posts'] = (int) $this->db->sql_fetchfield('total_posts');
			$this->db->sql_freeresult($result);

			$sql = 'SELECT COUNT(p.post_id) as main_posts
				FROM ' . POSTS_TABLE . ' p, ' . SPHINX_TABLE . ' m
				WHERE p.post_id <= m.max_doc_id
					AND m.counter_id = 1';
			$result = $this->db->sql_query($sql);
			$this->stats['main_posts'] = (int) $this->db->sql_fetchfield('main_posts');
			$this->db->sql_freeresult($result);
		}
	}

	/**
	* Returns a list of options for the ACP to display
	*
	* @return associative array containing template and config variables
	*/
	public function acp()
	{
		$config_vars = array(
			'fulltext_sphinx_data_path' => 'string',
			'fulltext_sphinx_host' => 'string',
			'fulltext_sphinx_port' => 'string',
			'fulltext_sphinx_indexer_mem_limit' => 'int',
		);

		$tpl = '
		<span class="error">' . $this->user->lang['FULLTEXT_SPHINX_CONFIGURE']. '</span>
		<dl>
			<dt><label for="fulltext_sphinx_data_path">' . $this->user->lang['FULLTEXT_SPHINX_DATA_PATH'] . $this->user->lang['COLON'] . '</label><br /><span>' . $this->user->lang['FULLTEXT_SPHINX_DATA_PATH_EXPLAIN'] . '</span></dt>
			<dd><input id="fulltext_sphinx_data_path" type="text" size="40" maxlength="255" name="config[fulltext_sphinx_data_path]" value="' . $this->config['fulltext_sphinx_data_path'] . '" /></dd>
		</dl>
		<dl>
			<dt><label for="fulltext_sphinx_host">' . $this->user->lang['FULLTEXT_SPHINX_HOST'] . $this->user->lang['COLON'] . '</label><br /><span>' . $this->user->lang['FULLTEXT_SPHINX_HOST_EXPLAIN'] . '</span></dt>
			<dd><input id="fulltext_sphinx_host" type="text" size="40" maxlength="255" name="config[fulltext_sphinx_host]" value="' . $this->config['fulltext_sphinx_host'] . '" /></dd>
		</dl>
		<dl>
			<dt><label for="fulltext_sphinx_port">' . $this->user->lang['FULLTEXT_SPHINX_PORT'] . $this->user->lang['COLON'] . '</label><br /><span>' . $this->user->lang['FULLTEXT_SPHINX_PORT_EXPLAIN'] . '</span></dt>
			<dd><input id="fulltext_sphinx_port" type="number" min="0" max="9999999999" name="config[fulltext_sphinx_port]" value="' . $this->config['fulltext_sphinx_port'] . '" /></dd>
		</dl>
		<dl>
			<dt><label for="fulltext_sphinx_indexer_mem_limit">' . $this->user->lang['FULLTEXT_SPHINX_INDEXER_MEM_LIMIT'] . $this->user->lang['COLON'] . '</label><br /><span>' . $this->user->lang['FULLTEXT_SPHINX_INDEXER_MEM_LIMIT_EXPLAIN'] . '</span></dt>
			<dd><input id="fulltext_sphinx_indexer_mem_limit" type="number" min="0" max="9999999999" name="config[fulltext_sphinx_indexer_mem_limit]" value="' . $this->config['fulltext_sphinx_indexer_mem_limit'] . '" /> ' . $this->user->lang['MIB'] . '</dd>
		</dl>
		<dl>
			<dt><label for="fulltext_sphinx_config_file">' . $this->user->lang['FULLTEXT_SPHINX_CONFIG_FILE'] . $this->user->lang['COLON'] . '</label><br /><span>' . $this->user->lang['FULLTEXT_SPHINX_CONFIG_FILE_EXPLAIN'] . '</span></dt>
			<dd>' . (($this->config_generate()) ? '<textarea readonly="readonly" rows="6" id="sphinx_config_data">' . htmlspecialchars($this->config_file_data, ENT_COMPAT) . '</textarea>' : $this->config_file_data) . '</dd>
		<dl>
		';

		// These are fields required in the config table
		return array(
			'tpl'		=> $tpl,
			'config'	=> $config_vars
		);
	}
}
