<?php
/**
 * Contain a class for special pages
 * @package MediaWiki
 * @subpackage Search
 */

/**
 * @package MediaWiki
 */
class SearchEngine {
	var $limit = 10;
	var $offset = 0;
	var $searchTerms = array();
	var $namespaces = array( NS_MAIN );
	var $showRedirects = false;

	/**
	 * Perform a full text search query and return a result set.
	 * If title searches are not supported or disabled, return null.
	 *
	 * @param string $term - Raw search term
	 * @return SearchResultSet
	 * @access public
	 * @abstract
	 */
	function searchText( $term ) {
		return null;
	}

	/**
	 * Perform a title-only search query and return a result set.
	 * If title searches are not supported or disabled, return null.
	 *
	 * @param string $term - Raw search term
	 * @return SearchResultSet
	 * @access public
	 * @abstract
	 */
	function searchTitle( $term ) {
		return null;
	}

	/**
	 * If an exact title match can be find, or a very slightly close match,
	 * return the title. If no match, returns NULL.
	 *
	 * @static
	 * @param string $term
	 * @return Title
	 * @private
	 */
	function getNearMatch( $term ) {
		# Exact match? No need to look further.
		$title = Title::newFromText( $term );
		if (is_null($title))
			return NULL;

		if ( $title->getNamespace() == NS_SPECIAL || $title->exists() ) {
			return $title;
		}

		# Now try all lower case (i.e. first letter capitalized)
		#
		$title = Title::newFromText( strtolower( $term ) );
		if ( $title->exists() ) {
			return $title;
		}

		# Now try capitalized string
		#
		$title = Title::newFromText( ucwords( strtolower( $term ) ) );
		if ( $title->exists() ) {
			return $title;
		}

		# Now try all upper case
		#
		$title = Title::newFromText( strtoupper( $term ) );
		if ( $title->exists() ) {
			return $title;
		}

		# Now try Word-Caps-Breaking-At-Word-Breaks, for hyphenated names etc
		$title = Title::newFromText( preg_replace_callback(
			'/\b([\w\x80-\xff]+)\b/',
			create_function( '$matches', '
				global $wgContLang;
				return $wgContLang->ucfirst($matches[1]);
				' ),
			$term ) );
		if ( $title->exists() ) {
			return $title;
		}

		global $wgCapitalLinks, $wgContLang;
		if( !$wgCapitalLinks ) {
			// Catch differs-by-first-letter-case-only
			$title = Title::newFromText( $wgContLang->ucfirst( $term ) );
			if ( $title->exists() ) {
				return $title;
			}
			$title = Title::newFromText( $wgContLang->lcfirst( $term ) );
			if ( $title->exists() ) {
				return $title;
			}
		}

		$title = Title::newFromText( $term );

		# Entering an IP address goes to the contributions page
		if ( ( $title->getNamespace() == NS_USER && User::isIP($title->getText() ) )
			|| User::isIP( trim( $term ) ) ) {
			return Title::makeTitle( NS_SPECIAL, "Contributions/" . $title->getDbkey() );
		}


		# Entering a user goes to the user page whether it's there or not
		if ( $title->getNamespace() == NS_USER ) {
			return $title;
		}

		# Quoted term? Try without the quotes...
		if( preg_match( '/^"([^"]+)"$/', $term, $matches ) ) {
			return SearchEngine::getNearMatch( $matches[1] );
		}

		return NULL;
	}

	function legalSearchChars() {
		return "A-Za-z_'0-9\\x80-\\xFF\\-";
	}

	/**
	 * Set the maximum number of results to return
	 * and how many to skip before returning the first.
	 *
	 * @param int $limit
	 * @param int $offset
	 * @access public
	 */
	function setLimitOffset( $limit, $offset = 0 ) {
		$this->limit = intval( $limit );
		$this->offset = intval( $offset );
	}

	/**
	 * Set which namespaces the search should include.
	 * Give an array of namespace index numbers.
	 *
	 * @param array $namespaces
	 * @access public
	 */
	function setNamespaces( $namespaces ) {
		$this->namespaces = $namespaces;
	}

	/**
	 * Make a list of searchable namespaces and their canonical names.
	 * @return array
	 * @access public
	 */
	function searchableNamespaces() {
		global $wgContLang;
		$arr = array();
		foreach( $wgContLang->getNamespaces() as $ns => $name ) {
			if( $ns >= NS_MAIN ) {
				$arr[$ns] = $name;
			}
		}
		return $arr;
	}

	/**
	 * Return a 'cleaned up' search string
	 *
	 * @return string
	 * @access public
	 */
	function filter( $text ) {
		$lc = $this->legalSearchChars();
		return trim( preg_replace( "/[^{$lc}]/", " ", $text ) );
	}
	/**
	 * Load up the appropriate search engine class for the currently
	 * active database backend, and return a configured instance.
	 *
	 * @return SearchEngine
	 * @private
	 */
	function create() {
		global $wgDBtype, $wgSearchType;
		if( $wgSearchType ) {
			$class = $wgSearchType;
		} elseif( $wgDBtype == 'mysql' ) {
			$class = 'SearchMySQL4';
		} else if ( $wgDBtype == 'postgres' ) {
			$class = 'SearchPostgres';
		} else {
			$class = 'SearchEngineDummy';
		}
		$search = new $class( wfGetDB( DB_SLAVE ) );
		$search->setLimitOffset(0,0);
		return $search;
	}

	/**
	 * 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
	 * @abstract
	 */
	function update( $id, $title, $text ) {
		// no-op
	}

	/**
	 * Update a search index record's title only.
	 * Title should be pre-processed.
	 *
	 * @param int $id
	 * @param string $title
	 * @abstract
	 */
    function updateTitle( $id, $title ) {
		// no-op
    }
}

/** @package MediaWiki */
class SearchResultSet {
	/**
	 * Fetch an array of regular expression fragments for matching
	 * the search terms as parsed by this engine in a text extract.
	 *
	 * @return array
	 * @access public
	 * @abstract
	 */
	function termMatches() {
		return array();
	}

	function numRows() {
		return 0;
	}

	/**
	 * Return true if results are included in this result set.
	 * @return bool
	 * @abstract
	 */
	function hasResults() {
		return false;
	}

	/**
	 * Some search modes return a total hit count for the query
	 * in the entire article database. This may include pages
	 * in namespaces that would not be matched on the given
	 * settings.
	 *
	 * Return null if no total hits number is supported.
	 *
	 * @return int
	 * @access public
	 */
	function getTotalHits() {
		return null;
	}

	/**
	 * Some search modes return a suggested alternate term if there are
	 * no exact hits. Returns true if there is one on this set.
	 *
	 * @return bool
	 * @access public
	 */
	function hasSuggestion() {
		return false;
	}

	/**
	 * Some search modes return a suggested alternate term if there are
	 * no exact hits. Check hasSuggestion() first.
	 *
	 * @return string
	 * @access public
	 */
	function getSuggestion() {
		return '';
	}

	/**
	 * Fetches next search result, or false.
	 * @return SearchResult
	 * @access public
	 * @abstract
	 */
	function next() {
		return false;
	}
}

/** @package MediaWiki */
class SearchResult {
	function SearchResult( $row ) {
		$this->mTitle = Title::makeTitle( $row->page_namespace, $row->page_title );
	}

	/**
	 * @return Title
	 * @access public
	 */
	function getTitle() {
		return $this->mTitle;
	}

	/**
	 * @return double or null if not supported
	 */
	function getScore() {
		return null;
	}
}

/**
 * @package MediaWiki
 */
class SearchEngineDummy {
	function search( $term ) {
		return null;
	}
	function setLimitOffset($l, $o) {}
	function legalSearchChars() {}
	function update() {}
	function setnamespaces() {}
	function searchtitle() {}
	function searchtext() {}
}
?>
