<?php
# Copyright (C) 2004 Brion Vibber <brion@pobox.com>
# http://www.mediawiki.org/
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
# http://www.gnu.org/copyleft/gpl.html

/**
 * @file
 * @ingroup Search
 */

/**
 * Search engine hook base class for Oracle (ConText).
 * @ingroup Search
 */
class SearchOracle extends SearchEngine {
	function __construct($db) {
		$this->db = $db;
	}

	/**
	 * Perform a full text search query and return a result set.
	 *
	 * @param string $term - Raw search term
	 * @return OracleSearchResultSet
	 * @access public
	 */
	function searchText( $term ) {
		$resultSet = $this->db->resultObject($this->db->query($this->getQuery($this->filter($term), true)));
		return new OracleSearchResultSet($resultSet, $this->searchTerms);
	}

	/**
	 * Perform a title-only search query and return a result set.
	 *
	 * @param string $term - Raw search term
	 * @return ORacleSearchResultSet
	 * @access public
	 */
	function searchTitle($term) {
		$resultSet = $this->db->resultObject($this->db->query($this->getQuery($this->filter($term), false)));
		return new MySQLSearchResultSet($resultSet, $this->searchTerms);
	}


	/**
	 * Return a partial WHERE clause to exclude redirects, if so set
	 * @return string
	 * @private
	 */
	function queryRedirect() {
		if ($this->showRedirects) {
			return '';
		} else {
			return 'AND page_is_redirect=0';
		}
	}

	/**
	 * Return a partial WHERE clause to limit the search to the given namespaces
	 * @return string
	 * @private
	 */
	function queryNamespaces() {
		if( is_null($this->namespaces) )
			return '';
		if ( !count( $this->namespaces ) ) {
			$namespaces = '0';
		} else {
			$namespaces = $this->db->makeList( $this->namespaces );
		}
		return 'AND page_namespace IN (' . $namespaces . ')';
	}

	/**
	 * Return a LIMIT clause to limit results on the query.
	 * @return string
	 * @private
	 */
	function queryLimit($sql) {
		return $this->db->limitResult($sql, $this->limit, $this->offset);
	}

	/**
	 * Does not do anything for generic search engine
	 * subclasses may define this though
	 * @return string
	 * @private
	 */
	function queryRanking($filteredTerm, $fulltext) {
		return ' ORDER BY score(1)';
	}

	/**
	 * Construct the full SQL query to do the search.
	 * The guts shoulds be constructed in queryMain()
	 * @param string $filteredTerm
	 * @param bool $fulltext
	 * @private
	 */
	function getQuery( $filteredTerm, $fulltext ) {
		return $this->queryLimit($this->queryMain($filteredTerm, $fulltext) . ' ' .
			$this->queryRedirect() . ' ' .
			$this->queryNamespaces() . ' ' .
			$this->queryRanking( $filteredTerm, $fulltext ) . ' ');
	}


	/**
	 * Picks which field to index on, depending on what type of query.
	 * @param bool $fulltext
	 * @return string
	 */
	function getIndexField($fulltext) {
		return $fulltext ? 'si_text' : 'si_title';
	}

	/**
	 * Get the base part of the search query.
	 *
	 * @param string $filteredTerm
	 * @param bool $fulltext
	 * @return string
	 * @private
	 */
	function queryMain( $filteredTerm, $fulltext ) {
		$match = $this->parseQuery($filteredTerm, $fulltext);
		$page        = $this->db->tableName('page');
		$searchindex = $this->db->tableName('searchindex');
		return 'SELECT page_id, page_namespace, page_title ' .
			"FROM $page,$searchindex " .
			'WHERE page_id=si_page AND ' . $match;
	}

	/** 
	 * Parse a user input search string, and return an SQL fragment to be used 
	 * as part of a WHERE clause
	 */
	function parseQuery($filteredText, $fulltext) {
		global $wgContLang;
		$lc = SearchEngine::legalSearchChars();
		$this->searchTerms = array();

		# FIXME: This doesn't handle parenthetical expressions.
		$m = array();
		$q = array();

		if (preg_match_all('/([-+<>~]?)(([' . $lc . ']+)(\*?)|"[^"]*")/',
			  $filteredText, $m, PREG_SET_ORDER)) {
			foreach($m as $terms) {
				$q[] = $terms[1] . $wgContLang->stripForSearch($terms[2]);

				if (!empty($terms[3])) {
					$regexp = preg_quote( $terms[3], '/' );
					if ($terms[4])
						$regexp .= "[0-9A-Za-z_]+";
				} else {
					$regexp = preg_quote(str_replace('"', '', $terms[2]), '/');
				}
				$this->searchTerms[] = $regexp;
			}
		}

		$searchon = $this->db->addQuotes(join(',', $q));
		$field = $this->getIndexField($fulltext);
		return " CONTAINS($field, $searchon, 1) > 0 ";
	}

	/**
	 * Create or update the search index record for the given page.
	 * Title and text should be pre-processed.
	 *
	 * @param int $id
	 * @param string $title
	 * @param string $text
	 */
	function update($id, $title, $text) {
		$dbw = wfGetDB(DB_MASTER);
		$dbw->replace('searchindex',
			array('si_page'),
			array(
				'si_page' => $id,
				'si_title' => $title,
				'si_text' => $text
			), 'SearchOracle::update' );
		$dbw->query("CALL ctx_ddl.sync_index('si_text_idx')");
		$dbw->query("CALL ctx_ddl.sync_index('si_title_idx')");
	}

	/**
	 * Update a search index record's title only.
	 * Title should be pre-processed.
	 *
	 * @param int $id
	 * @param string $title
	 */
	function updateTitle($id, $title) {
		$dbw = wfGetDB(DB_MASTER);

		$dbw->update('searchindex',
			array('si_title' => $title),
			array('si_page'  => $id),
			'SearchOracle::updateTitle',
			array());
	}
}

/**
 * @ingroup Search
 */
class OracleSearchResultSet extends SearchResultSet {
	function __construct($resultSet, $terms) {
		$this->mResultSet = $resultSet;
		$this->mTerms = $terms;
	}

	function termMatches() {
		return $this->mTerms;
	}

	function numRows() {
		return $this->mResultSet->numRows();
	}

	function next() {
		$row = $this->mResultSet->fetchObject();
		if ($row === false)
			return false;
		return new SearchResult($row);
	}
}
