<?php

	class kSearchHelper extends kHelper {
	
		
		/**
		 * Splits search phrase into keyword using quotes,plus and minus sings and spaces as split criteria
		 *
		 * @param string $keyword
		 * @return string
		 */
		function splitKeyword($keyword)
		{
			$quotes_re = '/([+\-]?)"(.*?)"/';
			$no_quotes_re = '/([+\-]?)([^ ]+)/';
			
			$quoted_kw = preg_match_all($quotes_re, $keyword, $res);
			foreach ($res[2] as $index => $kw) $final[$kw] = $res[1][$index];
			$keyword = preg_replace($quotes_re, '', $keyword);
			$not_quoted_kw =  preg_match_all($no_quotes_re, $keyword, $res);
			foreach ($res[2] as $index => $kw) $final[$kw] = $res[1][$index];
			
			return $final;
		}
		
		function getPositiveKeywords($keyword)
		{
			$keywords = $this->splitKeyword($keyword);
			
			$ret = Array();
			foreach ($keywords as $keyword => $sign) {
				if ($sign == '+' || $sign == '') {
					$ret[] = $keyword;
				}
			}
			return $ret;
		}
		
		function buildWhereClause($keyword, $fields)
		{
			$keywords = $this->splitKeyword($keyword);
			
			$normal_conditions = Array();
			$plus_conditions = Array();
			$minus_conditions = Array();
			
			foreach ($keywords as $keyword => $sign) {
				switch ($sign) {
					case '+':
						$plus_conditions[] =   implode(' LIKE "%'.$keyword.'%" OR ', $fields).' LIKE "%'.$keyword.'%"';
						break;
						
					case '-':
						foreach ($fields as $field) {
							$condition[] = $field.' NOT LIKE "%'.$keyword.'%" OR '.$field.' IS NULL';
						}
						$minus_conditions[] = '('.implode(') AND (', $condition).')';
						break;
						
					case '':
						$normal_conditions[] = implode(' LIKE "%'.$keyword.'%" OR ', $fields).' LIKE "%'.$keyword.'%"';
						break;
				}
			}
	
			// building where clause
			if ($normal_conditions) {
				$where_clause = '('.implode(') OR (', $normal_conditions).')';
			}
			else {
				$where_clause = '1';
			}
			
			if ($plus_conditions) {
				$where_clause = '('.$where_clause.') AND ('.implode(') AND (', $plus_conditions).')';
			}
			
			if ($minus_conditions) {
				$where_clause = '('.$where_clause.') AND ('.implode(') AND (', $minus_conditions).')';
			}
			
			return $where_clause;
		}
		
	}

?>