class.tree.php

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<?php
class _tree_struct {
        // Structure table and fields
        protected $table        = "";
        protected $fields       = array(
                        "id"            => false,
                        "parent_id"     => false,
                        "position"      => false,
                        "left"          => false,
                        "right"         => false,
                        "level"         => false
                );

        // Constructor
        function __construct($table = "tree", $fields = array()) {
                $this->table = $table;
                if(!count($fields)) {
                        foreach($this->fields as $k => &$v) { $v = $k; }
                }
                else {
                        foreach($fields as $key => $field) {
                                switch($key) {
                                        case "id":
                                        case "parent_id":
                                        case "position":
                                        case "left":
                                        case "right":
                                        case "level":
                                                $this->fields[$key] = $field;
                                                break;
                                }
                        }
                }
                // Database
                $this->db = new _database;
        }

        function _get_node($id) {
                $this->db->query("SELECT `".implode("` , `", $this->fields)."` FROM `".$this->table."` WHERE `".$this->fields["id"]."` = ".(int) $id);
                $this->db->nextr();
                return $this->db->nf() === 0 ? false : $this->db->get_row("assoc");
        }
        function _get_children($id, $recursive = false) {
                $children = array();
                if($recursive) {
                        $node = $this->_get_node($id);
                        $this->db->query("SELECT `".implode("` , `", $this->fields)."` FROM `".$this->table."` WHERE `".$this->fields["left"]."` >= ".(int) $node[$this->fields["left"]]." AND `".$this->fields["right"]."` <= ".(int) $node[$this->fields["right"]]." ORDER BY `".$this->fields["left"]."` ASC");
                }
                else {
                        $this->db->query("SELECT `".implode("` , `", $this->fields)."` FROM `".$this->table."` WHERE `".$this->fields["parent_id"]."` = ".(int) $id." ORDER BY `".$this->fields["position"]."` ASC");
                }
                while($this->db->nextr()) $children[$this->db->f($this->fields["id"])] = $this->db->get_row("assoc");
                return $children;
        }
        function _get_path($id) {
                $node = $this->_get_node($id);
                $path = array();
                if(!$node === false) return false;
                $this->db->query("SELECT `".implode("` , `", $this->fields)."` FROM `".$this->table."` WHERE `".$this->fields["left"]."` <= ".(int) $node[$this->fields["left"]]." AND `".$this->fields["right"]."` >= ".(int) $node[$this->fields["right"]]);
                while($this->db->nextr()) $path[$this->db->f($this->fields["id"])] = $this->db->get_row("assoc");
                return $path;
        }

        function _create($parent, $position) {
                return $this->_move(0, $parent, $position);
        }
        function _remove($id) {
                if((int)$id === 1) { return false; }
                $data = $this->_get_node($id);
                $lft = (int)$data[$this->fields["left"]];
                $rgt = (int)$data[$this->fields["right"]];
                $dif = $rgt - $lft + 1;

                // deleting node and its children
                $this->db->query("" . 
                        "DELETE FROM `".$this->table."` " . 
                        "WHERE `".$this->fields["left"]."` >= ".$lft." AND `".$this->fields["right"]."` <= ".$rgt
                );
                // shift left indexes of nodes right of the node
                $this->db->query("".
                        "UPDATE `".$this->table."` " . 
                                "SET `".$this->fields["left"]."` = `".$this->fields["left"]."` - ".$dif." " . 
                        "WHERE `".$this->fields["left"]."` > ".$rgt
                );
                // shift right indexes of nodes right of the node and the node's parents
                $this->db->query("" . 
                        "UPDATE `".$this->table."` " . 
                                "SET `".$this->fields["right"]."` = `".$this->fields["right"]."` - ".$dif." " . 
                        "WHERE `".$this->fields["right"]."` > ".$lft
                );

                $pid = (int)$data[$this->fields["parent_id"]];
                $pos = (int)$data[$this->fields["position"]];

                // Update position of siblings below the deleted node
                $this->db->query("" . 
                        "UPDATE `".$this->table."` " . 
                                "SET `".$this->fields["position"]."` = `".$this->fields["position"]."` - 1 " . 
                        "WHERE `".$this->fields["parent_id"]."` = ".$pid." AND `".$this->fields["position"]."` > ".$pos
                );
                return true;
        }
        function _move($id, $ref_id, $position = 0, $is_copy = false) {
                if((int)$ref_id === 0 || (int)$id === 1) { return false; }
                $sql            = array();                                              // Queries executed at the end
                $node           = $this->_get_node($id);                // Node data
                $nchildren      = $this->_get_children($id);    // Node children
                $ref_node       = $this->_get_node($ref_id);    // Ref node data
                $rchildren      = $this->_get_children($ref_id);// Ref node children

                $ndif = 2;
                $node_ids = array(-1);
                if($node !== false) {
                        $node_ids = array_keys($this->_get_children($id, true));
                        // TODO: should be !$is_copy && , but if copied to self - screws some right indexes
                        if(in_array($ref_id, $node_ids)) return false;
                        $ndif = $node[$this->fields["right"]] - $node[$this->fields["left"]] + 1;
                }
                if($position >= count($rchildren)) {
                        $position = count($rchildren);
                }

                // Not creating or copying - old parent is cleaned
                if($node !== false && $is_copy == false) {
                        $sql[] = "" . 
                                "UPDATE `".$this->table."` " . 
                                        "SET `".$this->fields["position"]."` = `".$this->fields["position"]."` - 1 " . 
                                "WHERE " . 
                                        "`".$this->fields["parent_id"]."` = ".$node[$this->fields["parent_id"]]." AND " . 
                                        "`".$this->fields["position"]."` > ".$node[$this->fields["position"]];
                        $sql[] = "" . 
                                "UPDATE `".$this->table."` " . 
                                        "SET `".$this->fields["left"]."` = `".$this->fields["left"]."` - ".$ndif." " . 
                                "WHERE `".$this->fields["left"]."` > ".$node[$this->fields["right"]];
                        $sql[] = "" . 
                                "UPDATE `".$this->table."` " . 
                                        "SET `".$this->fields["right"]."` = `".$this->fields["right"]."` - ".$ndif." " . 
                                "WHERE " . 
                                        "`".$this->fields["right"]."` > ".$node[$this->fields["left"]]." AND " . 
                                        "`".$this->fields["id"]."` NOT IN (".implode(",", $node_ids).") ";
                }
                // Preparing new parent
                $sql[] = "" . 
                        "UPDATE `".$this->table."` " . 
                                "SET `".$this->fields["position"]."` = `".$this->fields["position"]."` + 1 " . 
                        "WHERE " . 
                                "`".$this->fields["parent_id"]."` = ".$ref_id." AND " . 
                                "`".$this->fields["position"]."` >= ".$position." " . 
                                ( $is_copy ? "" : " AND `".$this->fields["id"]."` NOT IN (".implode(",", $node_ids).") ");

                $ref_ind = $ref_id === 0 ? (int)$rchildren[count($rchildren) - 1][$this->fields["right"]] + 1 : (int)$ref_node[$this->fields["right"]];
                $ref_ind = max($ref_ind, 1);

                $self = ($node !== false && !$is_copy && (int)$node[$this->fields["parent_id"]] == $ref_id && $position > $node[$this->fields["position"]]) ? 1 : 0;
                foreach($rchildren as $k => $v) {
                        if($v[$this->fields["position"]] - $self == $position) {
                                $ref_ind = (int)$v[$this->fields["left"]];
                                break;
                        }
                }
                if($node !== false && !$is_copy && $node[$this->fields["left"]] < $ref_ind) {
                        $ref_ind -= $ndif;
                }

                $sql[] = "" . 
                        "UPDATE `".$this->table."` " . 
                                "SET `".$this->fields["left"]."` = `".$this->fields["left"]."` + ".$ndif." " . 
                        "WHERE " . 
                                "`".$this->fields["left"]."` >= ".$ref_ind." " . 
                                ( $is_copy ? "" : " AND `".$this->fields["id"]."` NOT IN (".implode(",", $node_ids).") ");
                $sql[] = "" . 
                        "UPDATE `".$this->table."` " . 
                                "SET `".$this->fields["right"]."` = `".$this->fields["right"]."` + ".$ndif." " . 
                        "WHERE " . 
                                "`".$this->fields["right"]."` >= ".$ref_ind." " . 
                                ( $is_copy ? "" : " AND `".$this->fields["id"]."` NOT IN (".implode(",", $node_ids).") ");

                $ldif = $ref_id == 0 ? 0 : $ref_node[$this->fields["level"]] + 1;
                $idif = $ref_ind;
                if($node !== false) {
                        $ldif = $node[$this->fields["level"]] - ($ref_node[$this->fields["level"]] + 1);
                        $idif = $node[$this->fields["left"]] - $ref_ind;
                        if($is_copy) {
                                $sql[] = "" . 
                                        "INSERT INTO `".$this->table."` (" . 
                                                "`".$this->fields["parent_id"]."`, " . 
                                                "`".$this->fields["position"]."`, " . 
                                                "`".$this->fields["left"]."`, " . 
                                                "`".$this->fields["right"]."`, " . 
                                                "`".$this->fields["level"]."`" . 
                                        ") " . 
                                                "SELECT " . 
                                                        "".$ref_id.", " . 
                                                        "`".$this->fields["position"]."`, " . 
                                                        "`".$this->fields["left"]."` - (".($idif + ($node[$this->fields["left"]] >= $ref_ind ? $ndif : 0))."), " . 
                                                        "`".$this->fields["right"]."` - (".($idif + ($node[$this->fields["left"]] >= $ref_ind ? $ndif : 0))."), " . 
                                                        "`".$this->fields["level"]."` - (".$ldif.") " . 
                                                "FROM `".$this->table."` " . 
                                                "WHERE " . 
                                                        "`".$this->fields["id"]."` IN (".implode(",", $node_ids).") " . 
                                                "ORDER BY `".$this->fields["level"]."` ASC";
                        }
                        else {
                                $sql[] = "" . 
                                        "UPDATE `".$this->table."` SET " . 
                                                "`".$this->fields["parent_id"]."` = ".$ref_id.", " . 
                                                "`".$this->fields["position"]."` = ".$position." " . 
                                        "WHERE " . 
                                                "`".$this->fields["id"]."` = ".$id;
                                $sql[] = "" . 
                                        "UPDATE `".$this->table."` SET " . 
                                                "`".$this->fields["left"]."` = `".$this->fields["left"]."` - (".$idif."), " . 
                                                "`".$this->fields["right"]."` = `".$this->fields["right"]."` - (".$idif."), " . 
                                                "`".$this->fields["level"]."` = `".$this->fields["level"]."` - (".$ldif.") " . 
                                        "WHERE " . 
                                                "`".$this->fields["id"]."` IN (".implode(",", $node_ids).") ";
                        }
                }
                else {
                        $sql[] = "" . 
                                "INSERT INTO `".$this->table."` (" . 
                                        "`".$this->fields["parent_id"]."`, " . 
                                        "`".$this->fields["position"]."`, " . 
                                        "`".$this->fields["left"]."`, " . 
                                        "`".$this->fields["right"]."`, " . 
                                        "`".$this->fields["level"]."` " . 
                                        ") " . 
                                "VALUES (" . 
                                        $ref_id.", " . 
                                        $position.", " . 
                                        $idif.", " . 
                                        ($idif + 1).", " . 
                                        $ldif. 
                                ")";
                }
                foreach($sql as $q) { $this->db->query($q); }
                $ind = $this->db->insert_id();
                if($is_copy) $this->_fix_copy($ind, $position);
                return $node === false || $is_copy ? $ind : true;
        }
        function _fix_copy($id, $position) {
                $node = $this->_get_node($id);
                $children = $this->_get_children($id, true);

                $map = array();
                for($i = $node[$this->fields["left"]] + 1; $i < $node[$this->fields["right"]]; $i++) {
                        $map[$i] = $id;
                }
                foreach($children as $cid => $child) {
                        if((int)$cid == (int)$id) {
                                $this->db->query("UPDATE `".$this->table."` SET `".$this->fields["position"]."` = ".$position." WHERE `".$this->fields["id"]."` = ".$cid);
                                continue;
                        }
                        $this->db->query("UPDATE `".$this->table."` SET `".$this->fields["parent_id"]."` = ".$map[(int)$child[$this->fields["left"]]]." WHERE `".$this->fields["id"]."` = ".$cid);
                        for($i = $child[$this->fields["left"]] + 1; $i < $child[$this->fields["right"]]; $i++) {
                                $map[$i] = $cid;
                        }
                }
        }

        function _reconstruct() {
                $this->db->query("" . 
                        "CREATE TEMPORARY TABLE `temp_tree` (" . 
                                "`".$this->fields["id"]."` INTEGER NOT NULL, " . 
                                "`".$this->fields["parent_id"]."` INTEGER NOT NULL, " . 
                                "`". $this->fields["position"]."` INTEGER NOT NULL" . 
                        ") type=HEAP"
                );
                $this->db->query("" . 
                        "INSERT INTO `temp_tree` " . 
                                "SELECT " . 
                                        "`".$this->fields["id"]."`, " . 
                                        "`".$this->fields["parent_id"]."`, " . 
                                        "`".$this->fields["position"]."` " . 
                                "FROM `".$this->table."`"
                );

                $this->db->query("" . 
                        "CREATE TEMPORARY TABLE `temp_stack` (" . 
                                "`".$this->fields["id"]."` INTEGER NOT NULL, " . 
                                "`".$this->fields["left"]."` INTEGER, " . 
                                "`".$this->fields["right"]."` INTEGER, " . 
                                "`".$this->fields["level"]."` INTEGER, " . 
                                "`stack_top` INTEGER NOT NULL, " . 
                                "`".$this->fields["parent_id"]."` INTEGER, " . 
                                "`".$this->fields["position"]."` INTEGER " . 
                        ") type=HEAP"
                );
                $counter = 2;
                $this->db->query("SELECT COUNT(*) FROM temp_tree");
                $this->db->nextr();
                $maxcounter = (int) $this->db->f(0) * 2;
                $currenttop = 1;
                $this->db->query("" . 
                        "INSERT INTO `temp_stack` " . 
                                "SELECT " . 
                                        "`".$this->fields["id"]."`, " . 
                                        "1, " . 
                                        "NULL, " . 
                                        "0, " . 
                                        "1, " . 
                                        "`".$this->fields["parent_id"]."`, " . 
                                        "`".$this->fields["position"]."` " . 
                                "FROM `temp_tree` " . 
                                "WHERE `".$this->fields["parent_id"]."` = 0"
                );
                $this->db->query("DELETE FROM `temp_tree` WHERE `".$this->fields["parent_id"]."` = 0");

                while ($counter <= $maxcounter) {
                        $this->db->query("" . 
                                "SELECT " . 
                                        "`temp_tree`.`".$this->fields["id"]."` AS tempmin, " . 
                                        "`temp_tree`.`".$this->fields["parent_id"]."` AS pid, " . 
                                        "`temp_tree`.`".$this->fields["position"]."` AS lid " . 
                                "FROM `temp_stack`, `temp_tree` " . 
                                "WHERE " . 
                                        "`temp_stack`.`".$this->fields["id"]."` = `temp_tree`.`".$this->fields["parent_id"]."` AND " . 
                                        "`temp_stack`.`stack_top` = ".$currenttop." " . 
                                "ORDER BY `temp_tree`.`".$this->fields["position"]."` ASC LIMIT 1"
                        );

                        if ($this->db->nextr()) {
                                $tmp = $this->db->f("tempmin");

                                $q = "INSERT INTO temp_stack (stack_top, `".$this->fields["id"]."`, `".$this->fields["left"]."`, `".$this->fields["right"]."`, `".$this->fields["level"]."`, `".$this->fields["parent_id"]."`, `".$this->fields["position"]."`) VALUES(".($currenttop + 1).", ".$tmp.", ".$counter.", NULL, ".$currenttop.", ".$this->db->f("pid").", ".$this->db->f("lid").")";
                                $this->db->query($q);
                                $this->db->query("DELETE FROM `temp_tree` WHERE `".$this->fields["id"]."` = ".$tmp);
                                $counter++;
                                $currenttop++;
                        }
                        else {
                                $this->db->query("" . 
                                        "UPDATE temp_stack SET " . 
                                                "`".$this->fields["right"]."` = ".$counter.", " . 
                                                "`stack_top` = -`stack_top` " . 
                                        "WHERE `stack_top` = ".$currenttop
                                );
                                $counter++;
                                $currenttop--;
                        }
                }

                $temp_fields = $this->fields;
                unset($temp_fields["parent_id"]);
                unset($temp_fields["position"]);
                unset($temp_fields["left"]);
                unset($temp_fields["right"]);
                unset($temp_fields["level"]);
                if(count($temp_fields) > 1) {
                        $this->db->query("" . 
                                "CREATE TEMPORARY TABLE `temp_tree2` " . 
                                        "SELECT `".implode("`, `", $temp_fields)."` FROM `".$this->table."` "
                        );
                }
                $this->db->query("TRUNCATE TABLE `".$this->table."`");
                $this->db->query("" . 
                        "INSERT INTO ".$this->table." (" . 
                                        "`".$this->fields["id"]."`, " . 
                                        "`".$this->fields["parent_id"]."`, " . 
                                        "`".$this->fields["position"]."`, " . 
                                        "`".$this->fields["left"]."`, " . 
                                        "`".$this->fields["right"]."`, " . 
                                        "`".$this->fields["level"]."` " . 
                                ") " . 
                                "SELECT " . 
                                        "`".$this->fields["id"]."`, " . 
                                        "`".$this->fields["parent_id"]."`, " . 
                                        "`".$this->fields["position"]."`, " . 
                                        "`".$this->fields["left"]."`, " . 
                                        "`".$this->fields["right"]."`, " . 
                                        "`".$this->fields["level"]."` " . 
                                "FROM temp_stack " . 
                                "ORDER BY `".$this->fields["id"]."`"
                );
                if(count($temp_fields) > 1) {
                        $sql = "" . 
                                "UPDATE `".$this->table."` v, `temp_tree2` SET v.`".$this->fields["id"]."` = v.`".$this->fields["id"]."` ";
                        foreach($temp_fields as $k => $v) {
                                if($k == "id") continue;
                                $sql .= ", v.`".$v."` = `temp_tree2`.`".$v."` ";
                        }
                        $sql .= " WHERE v.`".$this->fields["id"]."` = `temp_tree2`.`".$this->fields["id"]."` ";
                        $this->db->query($sql);
                }
        }

        function _analyze() {
                $report = array();

                $this->db->query("" . 
                        "SELECT " . 
                                "`".$this->fields["left"]."` FROM `".$this->table."` s " . 
                        "WHERE " . 
                                "`".$this->fields["parent_id"]."` = 0 "
                );
                $this->db->nextr();
                if($this->db->nf() == 0) {
                        $report[] = "[FAIL]\tNo root node.";
                }
                else {
                        $report[] = ($this->db->nf() > 1) ? "[FAIL]\tMore than one root node." : "[OK]\tJust one root node.";
                }
                $report[] = ($this->db->f(0) != 1) ? "[FAIL]\tRoot node's left index is not 1." : "[OK]\tRoot node's left index is 1.";

                $this->db->query("" . 
                        "SELECT " . 
                                "COUNT(*) FROM `".$this->table."` s " . 
                        "WHERE " . 
                                "`".$this->fields["parent_id"]."` != 0 AND " . 
                                "(SELECT COUNT(*) FROM `".$this->table."` WHERE `".$this->fields["id"]."` = s.`".$this->fields["parent_id"]."`) = 0 ");
                $this->db->nextr();
                $report[] = ($this->db->f(0) > 0) ? "[FAIL]\tMissing parents." : "[OK]\tNo missing parents.";

                $this->db->query("SELECT MAX(`".$this->fields["right"]."`) FROM `".$this->table."`");
                $this->db->nextr();
                $n = $this->db->f(0);
                $this->db->query("SELECT COUNT(*) FROM `".$this->table."`");
                $this->db->nextr();
                $c = $this->db->f(0);
                $report[] = ($n/2 != $c) ? "[FAIL]\tRight index does not match node count." : "[OK]\tRight index matches count.";

                $this->db->query("" . 
                        "SELECT COUNT(`".$this->fields["id"]."`) FROM `".$this->table."` s " . 
                        "WHERE " . 
                                "(SELECT COUNT(*) FROM `".$this->table."` WHERE " . 
                                        "`".$this->fields["right"]."` < s.`".$this->fields["right"]."` AND " . 
                                        "`".$this->fields["left"]."` > s.`".$this->fields["left"]."` AND " . 
                                        "`".$this->fields["level"]."` = s.`".$this->fields["level"]."` + 1" . 
                                ") != " .
                                "(SELECT COUNT(*) FROM `".$this->table."` WHERE " . 
                                        "`".$this->fields["parent_id"]."` = s.`".$this->fields["id"]."`" . 
                                ") "
                        );
                $this->db->nextr();
                $report[] = ($this->db->f(0) > 0) ? "[FAIL]\tAdjacency and nested set do not match." : "[OK]\tNS and AJ match";

                return implode("<br />",$report);
        }

        function _dump($output = false) {
                $nodes = array();
                $this->db->query("SELECT * FROM ".$this->table." ORDER BY `".$this->fields["left"]."`");
                while($this->db->nextr()) $nodes[] = $this->db->get_row("assoc");
                if($output) {
                        echo "<pre>";
                        foreach($nodes as $node) {
                                echo str_repeat("&#160;",(int)$node[$this->fields["level"]] * 2);
                                echo $node[$this->fields["id"]]." (".$node[$this->fields["left"]].",".$node[$this->fields["right"]].",".$node[$this->fields["level"]].",".$node[$this->fields["parent_id"]].",".$node[$this->fields["position"]].")<br />";
                        }
                        echo str_repeat("-",40);
                        echo "</pre>";
                }
                return $nodes;
        }
        function _drop() {
                $this->db->query("TRUNCATE TABLE `".$this->table."`");
                $this->db->query("" . 
                                "INSERT INTO `".$this->table."` (" . 
                                        "`".$this->fields["id"]."`, " . 
                                        "`".$this->fields["parent_id"]."`, " . 
                                        "`".$this->fields["position"]."`, " . 
                                        "`".$this->fields["left"]."`, " . 
                                        "`".$this->fields["right"]."`, " . 
                                        "`".$this->fields["level"]."` " . 
                                        ") " . 
                                "VALUES (" . 
                                        "1, " . 
                                        "0, " . 
                                        "0, " . 
                                        "1, " . 
                                        "2, " . 
                                        "0 ". 
                                ")");
        }
}

class json_tree extends _tree_struct { 
        function __construct($table = "tree", $fields = array(), $add_fields = array("title" => "title", "type" => "type")) {
                parent::__construct($table, $fields);
                $this->fields = array_merge($this->fields, $add_fields);
                $this->add_fields = $add_fields;
        }

        function create_node($data) {
                $id = parent::_create((int)$data[$this->fields["id"]], (int)$data[$this->fields["position"]]);
                if($id) {
                        $data["id"] = $id;
                        $this->set_data($data);
                        return  "{ \"status\" : 1, \"id\" : ".(int)$id." }";
                }
                return "{ \"status\" : 0 }";
        }
        function set_data($data) {
                if(count($this->add_fields) == 0) { return "{ \"status\" : 1 }"; }
                $s = "UPDATE `".$this->table."` SET `".$this->fields["id"]."` = `".$this->fields["id"]."` "; 
                foreach($this->add_fields as $k => $v) {
                        if(isset($data[$k]))    $s .= ", `".$this->fields[$v]."` = \"".$this->db->escape($data[$k])."\" ";
                        else                                    $s .= ", `".$this->fields[$v]."` = `".$this->fields[$v]."` ";
                }
                $s .= "WHERE `".$this->fields["id"]."` = ".(int)$data["id"];
                $this->db->query($s);
                return "{ \"status\" : 1 }";
        }
        function rename_node($data) { return $this->set_data($data); }

        function move_node($data) { 
                $id = parent::_move((int)$data["id"], (int)$data["ref"], (int)$data["position"], (int)$data["copy"]);
                if(!$id) return "{ \"status\" : 0 }";
                if((int)$data["copy"] && count($this->add_fields)) {
                        $ids    = array_keys($this->_get_children($id, true));
                        $data   = $this->_get_children((int)$data["id"], true);

                        $i = 0;
                        foreach($data as $dk => $dv) {
                                $s = "UPDATE `".$this->table."` SET `".$this->fields["id"]."` = `".$this->fields["id"]."` "; 
                                foreach($this->add_fields as $k => $v) {
                                        if(isset($dv[$k]))      $s .= ", `".$this->fields[$v]."` = \"".$this->db->escape($dv[$k])."\" ";
                                        else                            $s .= ", `".$this->fields[$v]."` = `".$this->fields[$v]."` ";
                                }
                                $s .= "WHERE `".$this->fields["id"]."` = ".$ids[$i];
                                $this->db->query($s);
                                $i++;
                        }
                }
                return "{ \"status\" : 1, \"id\" : ".$id." }";
        }
        function remove_node($data) {
                $id = parent::_remove((int)$data["id"]);
                return "{ \"status\" : 1 }";
        }
        function get_children($data) {
                $tmp = $this->_get_children((int)$data["id"]);
                if((int)$data["id"] === 1 && count($tmp) === 0) {
                        $this->_create_default();
                        $tmp = $this->_get_children((int)$data["id"]);
                }
                $result = array();
                if((int)$data["id"] === 0) return json_encode($result);
                foreach($tmp as $k => $v) {
                        $result[] = array(
                                "attr" => array("id" => "node_".$k, "rel" => $v[$this->fields["type"]]),
                                "data" => $v[$this->fields["title"]],
                                "state" => ((int)$v[$this->fields["right"]] - (int)$v[$this->fields["left"]] > 1) ? "closed" : ""
                        );
                }
                return json_encode($result);
        }
        function search($data) {
                $this->db->query("SELECT `".$this->fields["left"]."`, `".$this->fields["right"]."` FROM `".$this->table."` WHERE `".$this->fields["title"]."` LIKE '%".$this->db->escape($data["search_str"])."%'");
                if($this->db->nf() === 0) return "[]";
                $q = "SELECT DISTINCT `".$this->fields["id"]."` FROM `".$this->table."` WHERE 0 ";
                while($this->db->nextr()) {
                        $q .= " OR (`".$this->fields["left"]."` < ".(int)$this->db->f(0)." AND `".$this->fields["right"]."` > ".(int)$this->db->f(1).") ";
                }
                $result = array();
                $this->db->query($q);
                while($this->db->nextr()) { $result[] = "#node_".$this->db->f(0); }
                return json_encode($result);
        }

        function _create_default() {
                $this->_drop();
                $this->create_node(array(
                        "id" => 1,
                        "position" => 0,
                        "title" => "C:",
                        "type" => "drive"
                ));
                $this->create_node(array(
                        "id" => 1,
                        "position" => 1,
                        "title" => "D:",
                        "type" => "drive"
                ));
                $this->create_node(array(
                        "id" => 2,
                        "position" => 0,
                        "title" => "_demo",
                        "type" => "folder"
                ));
                $this->create_node(array(
                        "id" => 2,
                        "position" => 1,
                        "title" => "_docs",
                        "type" => "folder"
                ));
                $this->create_node(array(
                        "id" => 4,
                        "position" => 0,
                        "title" => "index.html",
                        "type" => "default"
                ));
                $this->create_node(array(
                        "id" => 5,
                        "position" => 1,
                        "title" => "doc.html",
                        "type" => "default"
                ));
        }
}

?>