/**
 * Обертка над БД
 *
 * @author Fragster
 */
class DB extends PDO {

    /**
     *
     * @var DB
     */
    private static $singleton;
    private $engine;
    private $host;
    private $database;
    private $user;
    private $pass;

    public function __construct() {
        $this->engine = 'mysql';
        $this->host = Config::$db_host;
        $this->database = Config::$db_database;
        $this->user = Config::$db_user;
        $this->pass = Config::$db_password;
        $dns = $this->engine . ':dbname=' . $this->database . ";host=" . $this->host;
        parent::__construct($dns, $this->user, $this->pass);
        $this->exec("SET NAMES utf8");
        $this->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    }

    /**
     *
     * @return DB
     */
    static function Init() {
        if (!self::$singleton) {
            self::$singleton = new DB;
        }
        return self::$singleton;
    }

    public function arrayPrepare($query, array $input_parameters) {
        $query = str_replace("\n", "", $query);

        $params = array();
        foreach ($input_parameters as $key => $value) {
            if (is_array($value)) {
                $implode = '';
                $delim = '';
                foreach ($value as $valueKey => $valueValue) {
                    $params[$key . '_' . $valueKey] = $valueValue;
                    $implode.= $delim . $key . '_' . $valueKey;
                    $delim = ', ';
                }
                $query = str_replace($key, $implode, $query);
            } else {
                $params[$key] = $value;
            }
        }

        try {
            $statement = $this->prepare($query);
        } catch (Exception $exc) {
            throw new Exception($query."\n".$this->errorInfo());
        }

        foreach ($params as $key => $value) {
            $statement->bindValue($key, $value)."\n";
        }
        return $statement;
    }

    public function multiInsert($query, array $insert_array) {
        $query = str_replace("\n", "", $query);

        $query1 = array();
        preg_match('/.*values\s*/im', $query, $query1);
        $query1 = $query1[0];

        $placeholders = array();
        preg_match_all('/:\w+/im', $query, $placeholders);
        $placeholders = $placeholders[0];
        $rowDelim = '';
        foreach ($insert_array as $key => $value) {
            $query1.= $rowDelim . '(';
            $rowDelim = ', ';
            $fieldDelim = '';
            foreach ($placeholders as $placeholder) {
                $query1.= $fieldDelim . $placeholder . '_' . $key;
                $fieldDelim = ', ';
            }
            $query1.= ')';
        }

        try {
            $statement = $this->prepare($query1);
        } catch (Exception $exc) {
            throw new Exception($query1."\n".$this->errorInfo());
        }

        foreach ($insert_array as $key => $value) {
            foreach ($placeholders as $placeholder) {
                $var = $value[$placeholder];
                $statement->bindValue($placeholder . '_' . $key, $var);
            }
        }

        //throw new Exception(print_r($guids, true));
        $statement->execute();
    }

}