<?php
/**
* Search lib by John-Paul Durrieu
*/

// Token types
define("TOKEN_STRING",       0);
define("TOKEN_AND",          1);
define("TOKEN_OR",           2);
define("TOKEN_NOT",          3);
define("TOKEN_LEFTPAREN",    4);
define("TOKEN_RIGHTPAREN",   5);
define("TOKEN_PLUS",         6);
define("TOKEN_MINUS",        7);

/**
* Tokenize a search criteria string in pseudo-google format
* e.g: this that OR (this and "the other") +this -that \+also
*
* @returns array of (tokentype, token) tuples.
* e.g:  ((TOKEN_STRING, "this"),
*        (TOKEN_STRING, "that"),
*        (TOKEN_OR, "OR"),
*        (TOKEN_LEFTPAREN, "("),
*        (TOKEN_STRING, "this"),
*        (TOKEN_AND, "and"),
*        (TOKEN_STRING, "the other"),
*        (TOKEN_RIGHTPAREN, ")"),
*        (TOKEN_PLUS, "+"),
*        (TOKEN_STRING, "this"),
*        (TOKEN_MINUS, "-"),
*        (TOKEN_STRING, "that"),
*        (TOKEN_STRING, "+also"))
*
* Based on example code in the PHP manual on php.net
*/
function tokenize($criteria) {

    $tokens = array(
        TOKEN_STRING => '',
        TOKEN_AND => 'and',
        TOKEN_OR => 'or',         
        TOKEN_NOT => 'not',        
        TOKEN_LEFTPAREN => '(',  
        TOKEN_RIGHTPAREN => ')', 
        TOKEN_PLUS => '+',       
        TOKEN_MINUS => '-');      

    // automaton [states][chartypes] => actions
    // states:
    // STATE_SPACE		      0
    // STATE_UNQUOTED	      1
    // STATE_DOUBLEQUOTED   2
    // STATE_ESCAPED		    3

    $chart = array(
        0   => array(' '=>'',   '"'=>'d',  '\\'=>'ue', '+'=>'uaw ', '-'=>'uaw ', '('=>'uaw ', ')'=>'uaw ', 0 =>'ua'),
        1   => array(' '=>'w ', '"'=>'wd', '\\'=>'e',  '+'=>'waw',  '-'=>'waw',  '('=>'waw',  ')'=>'waw',  0 =>'a'),
        2   => array(' '=>'a',  '"'=>'w ', '\\'=>'e',  '+'=>'a',    '-'=>'a',    '('=>'a',    ')'=>'a',    0 =>'a'),
        3   => array(' '=>'ap', '"'=>'ap', '\\'=>'ap', '+'=>'ap',   '-'=>'ap',   '('=>'ap',   ')'=>'ap',   0 =>'ap'));

    $state = 0;					// STATE_SPACE
    $previous = '';     // stores current state when encountering a backslash (which changes $state to STATE_ESCAPED, but has to fall back into the previous $state afterwards)
    $out = array();     // the return value
    $word = '';
    $type = '';         // type of character

    for ($i=0; $i<=strlen($criteria); $i++) {
        $char = substr($criteria, $i, 1);
        $type = $char;
        if (!isset($chart[0][$type])) {
            $type = 0; //other
            // grab all consecutive non word-ending characters
            preg_match("/[ \+\-\(\)\"\\\]/", $criteria, $matches, PREG_OFFSET_CAPTURE, $i);
            if ($matches) {
                $matches = $matches[0];
                $char = substr($criteria, $i, $matches[1]-$i); // yep, $char length can be > 1
                $i = $matches[1] - 1;
            }else{
                // no more match on special characters, that must mean this is the last word!
                // the .= below is because we *might* be in the middle of a word that just contained special chars
                $word .= substr($criteria, $i);
                break; // jumps out of the for() loop
            }
        }
        $actions = $chart[$state][$type];
        for($j=0; $j<strlen($actions); $j++) {
            $act = substr($actions, $j, 1);
            if ($act == ' ') $state = 0; //STATE_SPACE
            if ($act == 'u') $state = 1; //STATE_UNQUOTED
            if ($act == 'd') $state = 2; //STATE_DOUBLEQUOTED
            if ($act == 'e') { $previous = $state; $state = 3; } //STATE_ESCAPED
            if ($act == 'a') $word .= $char;
            if ($act == 'p') $state = $previous;
            if ($act == 'w') {
                if (!empty($word)) {
                    $tokentype = TOKEN_STRING;
                    if ($state == 1) {
                        //unquoted word, so look for keywords or operators
                        $tokentype = array_search(strtolower($word), $tokens);
                        if (!$tokentype) $tokentype = TOKEN_STRING;
                    }
                    $out[] = array($tokentype, $word);
                    $word = ''; 
                }
            }
        } //for j
    } //for i

    if (!empty($word)) {
        $tokentype = TOKEN_STRING;
        if ($state == 1) {
            //unquoted word, so look for keywords or operators
            $tokentype = array_search(strtolower($word), $tokens);
            if (!$tokentype) $tokentype = TOKEN_STRING;
        }
        $out[] = array($tokentype, $word);
        $word = ''; 
    }
    return $out;
} //tokenize

/**
 * parse the criteria string according to a subset of the Google search syntax:
 *
 * example:  this too AND +this OR (these AND "the other") -notthis
 *
 * @return array of criterias, each criteria being an array:
 * array (0 => operator,       ' AND ',' OR ',' AND NOT '
 *        1 => value,          the criteria's string value
 *        2 => wildcard flag,  TRUE if wildcard matching, FALSE for strict matching
 *        3 => nesting)        parentheses nesting level 0..n
 *
 * for convenience, the operator of the first criteria is blank.
 */
function parsecriteria($criteria) {

	$results = array();
	$tokens = array();
	
	$thisresult = array('','',TRUE,0);
	$nesting = 0;
	//var_dump($criteria); //@@@
	
	//replace html quoting put there by some browsers, then tokenize
	$tokens = tokenize(str_replace ('&quot;', '"', $criteria));
	//var_dump($tokens); //@@@
	
	foreach ($tokens as $token) {
	    switch ($token[0]) { 
	        case TOKEN_AND:
	            $thisresult[0] = ' AND ';
	            $thisresult[2] = TRUE; //reset wildcard in case of bad syntax
	            break;
	
	        case TOKEN_OR:
	            $thisresult[0] = ' OR ';
	            $thisresult[2] = TRUE; //reset  wildcard in case of bad syntax
	            break;
	
	        case TOKEN_PLUS:
	            $thisresult[2] = FALSE;
	            break;
	
	        case TOKEN_NOT:
	        case TOKEN_MINUS:
	            $thisresult[0] .= ' NOT '; //NOT or AND NOT
	            break;
	
	        case TOKEN_LEFTPAREN:
	            $nesting += 1;
	            $thisresult[2] = TRUE; //reset just in case of bad syntax
	            break;
	
	        case TOKEN_RIGHTPAREN:
	            $nesting -= 1;
	            $thisresult[2] = TRUE; //reset just in case of bad syntax
	            break;
	
	        default:
	            // anything else -> output "as is"
	            $thisresult[1] .= $token[1];
	            $thisresult[3]  = $nesting;
	            $results[] = $thisresult;
	            $thisresult = array(' AND ','',TRUE,0);
	            break;
	    }
	} //foreach $tokens
	return $results;

} //parsecriteria


function assemble_query ($criteria, $searchfields) {
	global $mysql, $username, $search;
	$whereCriterias = parsecriteria ($criteria); 
	//var_dump($whereCriterias); //@@@
	
	
	$whereData = array();
	$columnNumber = 0;
	
	$whereClause = "";
	$nesting = 0;
	foreach ($whereCriterias as $mycriteria) {
	    $whereClause .= $mycriteria[0];
	
	    $thisnesting = $mycriteria[3];
	    if ($thisnesting >= $nesting) {
	        $whereClause .= str_repeat('(', $thisnesting - $nesting);
	    } else {
	        $whereClause .= str_repeat(')', $nesting - $thisnesting);
	    }
	    $nesting = $thisnesting;
	
	    $firstcolumn = TRUE;
	    $whereClause .= ' (';
	    foreach ($searchfields as $column) {
	        if ($firstcolumn) {
	            $firstcolumn = FALSE;
	        } else    {
	            $whereClause .= ' OR ';
	        }
	
	        if ($mycriteria[2]) {
	            $whereClause .= "$column LIKE " . '\'' .'%' . $mysql->escape ($mycriteria[1]) . '%' . '\'' ;
	        } else {
	            /* no wildcard, so match exact words using a REGEXP */
	            $whereClause .= "$column RLIKE " . '\'' . '[[:<:]]' . $mysql->escape ($mycriteria[1]) .  '[[:>:]]' . '\'';
	        }
	    } //foreach $column
	    $whereClause .= ')';
	} //foreach $whereCriterias

	$whereClause .= str_repeat(')', $nesting);

	$query = sprintf ("SELECT bookmark.title,
				bookmark.url,
				bookmark.description,
				UNIX_TIMESTAMP(bookmark.date) AS timestamp,
				bookmark.childof,
				bookmark.id,
				bookmark.favicon,
				bookmark.public,
				folder.name,
				folder.id AS fid,
				folder.public AS fpublic
				FROM bookmark LEFT JOIN folder ON bookmark.childof=folder.id

				WHERE bookmark.user='%s'
				AND bookmark.deleted!='1'
				AND ( %s )
				ORDER BY title",
				$mysql->escape ($username),
				$whereClause);

	return $query;

}

?>