phpis shit

<?php
    class queryBuilder
    {
        const MYSQL_ERR = -1;
        const SUCCESS = 0;
        const QUERY_ERR = 1;

        const UNKNOWN_TYPE = 11;
        const SIZE_NOT_MATCHED = 12;


        function __construct($auth_host,$auth_user,$auth_password,$auth_db)
        {
            $this->auth_host = $auth_host;
            $this->auth_user = $auth_user;
            $this->auth_password = $auth_password;
            $this->auth_db = $auth_db;
            $this->sql = "";

            $this->mysqli = new Mysqli($auth_host,$auth_user,$auth_password,$auth_db);
        }
        private function openDb(){
            if (!$this->mysqli->ping()) {
                $this->mysqli = new Mysqli($auth_host,$auth_user,$auth_password,$auth_db);
            }
        }
        private function closeDb(){
            if ($this->mysqli->ping()) {
                $this->mysqli->close();
            }
        }
        private function isTableExist(){
            if (!empty($this->table)) {
                throw new Exception("table is not set", $this::QUERY_ERR);

            }
        }
        protected function getSqlResult($sql){
            if ($this->mysqli->ping()) {
                $res = $this->mysqli->query($sql);
                if (!is_bool($res)) {
                    $ret = array_merge($res->fetch_array(),array('status' => $this::SUCCESS));
                }
                else{
                    $ret = array('status' => $this::QUERY_ERR,'info' => $this->mysqli->error);
                }
                return $ret;
            }
            else{
                throw new Exception("Error Connect Mysql [error : ".$this->mysqli->error."]", MYSQL_ERR);
            }
        }

        private function kvCommand($command,,$keys,$values){
            if (is_array($keys) && is_array($values) && !empty($command)){
                isTableExist();
                $keyCount = count($keys);
                $valueCount = count($values);
                if ($keyCount > 0 && $valueCount > 0 && $valueCount <= $keyCount) {
                    $setValues = "";
                    for ($index = 0; $index < $keyCount; $index++) {
                        $values[$index] = is_string($values[$index]) ? "'".$values[$index]."'" : $values[$index];
                        $setValues .= "`".$keys[$index]."` = ".$values[$index];
                        if($index < $keyCount - 1){
                            $setValues .= " AND ";
                        }
                    };
                    $sql = $command." ".$setValues."";
                    return $sql;
                }
                else{
                    throw new Exception("Key Value length is Not Matched", $this::SIZE_NOT_MATCHED);
                }
            }
            else{
                throw new Exception("Unknown Type (Only Array)", $this::UNKNOWN_TYPE);
            }
        }
        private function upadteCommand($command,$operator,$keys,$values){
            if (is_array($keys) && is_array($values) && !empty($command)){
                isTableExist();
                $keyCount = count($keys);
                $valueCount = count($values);
                if ($keyCount > 0 && $valueCount > 0 && $valueCount <= $keyCount) {
                    $setValues = "";
                    for ($index = 0; $index < $keyCount; $index++) {
                        $values[$index] = is_string($values[$index]) ? "'".$values[$index]."'" : $values[$index];
                        $setValues .= "`".$keys[$index]."` = ".$values[$index];
                        if($index < $keyCount - 1){
                            $setValues .= ", ";
                        }
                    };
                    $sql = $command." `".$this->table."` ".$operator." ".$setValues."";
                    return $sql;
                }
                else{
                    throw new Exception("Key Value length is Not Matched", $this::SIZE_NOT_MATCHED);
                }
            }
            else{
                throw new Exception("Unknown Type (Only Array)", $this::UNKNOWN_TYPE);
            }
        }
        private function insertCommand($command,$operator,$keys,$values){
            if (is_array($keys) && is_array($values) && !empty($command)){
                isTableExist();
                $keyCount = count($keys);
                $valueCount = count($values);
                if ($keyCount > 0 && $valueCount > 0 && $valueCount === $keyCount) {
                    $column = "`".(is_array($keys) ? join($keys,"`,`") : $keys)."`";
                    $values = (is_array($keys) ? join($keys,",") : $keys);

                    $sql = $command." `".$this->table."` (".$column.") ".$operator." (".$values.")";
                    return $sql;
                }
                else{
                    throw new Exception("Key Value length is Not Matched", $this::SIZE_NOT_MATCHED);
                }
            }
            else{
                throw new Exception("Unknown Type (Only Array)", $this::UNKNOWN_TYPE);
            }
        }
        function query($sql){
            return $this->getSqlResult($sql);
        }
        function setTable($table){
            $this->table = $table;
            return $this;
        }
        function select(...$column){
            $this->isTableExist();
            $column = "`".(is_array($column) ? join($column,"`,`") : $column)."`";
            $this->sql += "SELECT `".$column." FROM `".$this->table."`";
            $this->mode = "select";
            return $this;
        }
        function insert($keys,$values){
            $this->sql += insertCommand("INSERT INTO","VALUES",$keys,$values);
            $this->mode = "insert";
            return $this;
        }
        function delete(){

            $this->isTableExist();
            $this->sql += "DELETE FROM `".$this->table."`";
            $this->mode = "delete";
            return $this;
        }
        function update($keys,$values){
            $this->sql += upadteCommand("UPDATE","SET",$keys,$values);
            $this->mode = "update";
            return $this;
        }
        function limit(){
            $arg = func_get_args();
            $countPreifx = (!empty($arg[0])) ? "LIMIT ".$arg[0] : "";
            $limitPreifx = (!empty($arg[1])) ? ",".$arg[1] : "";
            $this->sql += $countPreifx.$limitPreifx;
        }
        function where($keys,$values){
            $this->sql += kvCommand("WHERE",$keys,$values);
            return $this;
        }
        function exec(){
            return $this->getSqlResult($this->sql);
            $this->table = null;
        }
        function __destruct()
        {
            $this->closeDb();
        }
    }
?>