<?php
/**
 * Spellcheck Library
 *
 * @package kernel
 * @version $Header$
 *
 * Copyright (c) 2004 bitweaver.org
 * Copyright (c) 2003 tikwiki.org
 * Copyright (c) 2002-2003, Luis Argerich, Garland Foster, Eduardo Polidor, et. al.
 * All Rights Reserved. See below for details and a complete list of authors.
 * Licensed under the GNU LESSER GENERAL PUBLIC LICENSE. See http://www.gnu.org/copyleft/lesser.html for details
 *
 * $Id$
 *
 * A spell checking library.
 *
 * Currently used for BitBase.
 * @author lrargerich <lrargerich@yahoo.com>
 * created 2002/11/14
 */

/**
 * Spellcheck Library
 *
 * @package kernel
 * @todo does not need to inherit BitBase class. Should hold a BitDb connection as a
 * global variable.
 */
class Bablotron extends BitBase
{
	/**
	* @todo Variable is scoped here but not really used in this scope below.
	*/
	public $words;
	/**
	* Used to store the current language.
	*
	* @todo Not sure where this gets set from. Is used in other libraries.
	*/
	public $lan;
	/**
	* @todo Empty variable - does nothing
	*/
	public $db;
	/**
	* Spellchecking and finding of alternative words
	*/
	function __construct( $lan )
	{
		parent::__construct();
		$this->lan = $lan;
	}
	/**
	* @todo Empty function - does nothing
	*/
	function sql_error($query, $result)
	{

	}
	/**
	* Spellchecks a line of text
	* @param text line of text
	* @param threshold the similarity threshold
	* @returns array a list of alternative words if spelt incorrectly
	*/
	function spellcheck_text($text, $threshold = 5)
	{
		$words = preg_split("/\s/", $text);
		$results = [];
		foreach ($words as $word)
		{
			if (!$this->word_exists($word))
			{
				$results[$word] = $this->find_similar_words($word, $threshold);
			}
		}
		return $results;
	}
	/**
	* Spellchecks a word
	* @param word the word
	* @param threshold the similarity threshold
	* @returns array a list of alternative words if spelt incorrectly
	*/
	function spellcheck_word($word, $threshold = 5)
	{
		$results = [];
		if (!$this->word_exists($word))
		{
			$results[$word] = $this->find_similar_words($word, $threshold);
		}
		return $results;
	}
	/**
	* Spellchecks a line of text
	* @param text line of text
	* @param threshold Not used @todo param threshold Not used
	* @return array a list of incorrectly spelt words or words not found in the database
	*/
	function quick_spellcheck_text($text, $threshold = 5)
	{
		$words = preg_split("/\s/", $text);
		$results = [];
		foreach ($words as $word)
		{
			if (!$this->word_exists($word))
			{
				$results[] = $word;
			}
		}
		return $results;
	}
	/**
	* Lists similar words by relevance threshold.
	* @param word the word
	* @param threshold the similarity threshold
	* @return array of similar words and Levenshtein distance
	*/
	function find_similar_words($word, $threshold)
	{
		$similar = [];
		$tbl = 'babl_words_' . $this->lan;
		$word = addslashes( ( trim( $word ) ) );
		$sndx = substr($word, 0, 2);
		$query = "select `word` AS word from `$tbl` where `di`=?";
		@$result = $this->mDb->query($query, [$sndx]);
		while ($res = $result->fetchRow() )
		{
			$tword = $res["word"];
			$lev = levenshtein($tword, $word);
			if (count($similar) < $threshold)
			{
				$similar[$tword] = $lev;
				asort ($similar);
			}
			else
			{
				// If the array is full then if the lev is better than the worst lev
				// then update $keys = array_keys($similar);
				$last_key = $keys[count($keys) - 1];
				if ($lev < $similar[$last_key])
				{
					unset ($similar[$last_key]);
					$similar[$tword] = $lev;
					asort ($similar);
				}
			}
		}
		return $similar;
	}
	/**
	* Checks if a word exists
	* @param word the word
	* @return int number of matches
	*/
	function word_exists($word)
	{
		$tbl = 'babl_words_' . $this->lan;
		$word = addslashes( ( trim( $word ) ) );
		$query = "select `word` AS word from `$tbl` where `word`=?";
		$result = $this->mDb->query($query,[$word]);
		return $result->numRows();
	}
	/**
	* @todo Empty function - does nothing
	*/
	function find_similar($word, $threshold)
	{
	}
}
?>