<?php
class app_db_mysqli implements app_db_interface
{
    /**
     * MySQLi object
     * @var mysqli
     */
    protected static $_mysqli = array();

    /**
     * MySQLi Result object
     * @var mysqli_result
     */
    protected $_result;

    /**
     * @var string
     */
    protected $_use_mirror = "default";


    /**
     *
     * @var array
     */
    protected $servers = array(
            "default" => [ "localhost", "root", "pass", "db" ],
            "russia-mirror" => [ "russia", "root", "pass", "db" ],
            "europe-mirror" => [ "europe", "root", "pass", "db" ],
    );

    /**
     *
     * @param unknown $string
     * @throws app_exception
     */
    public function useMirror($string)
    {
        if (!isset($this->servers[$string]))
        {
            throw new app_exception("Mirror not exists", 503);

        }

        $this->_use_mirror = $string;

        return $this;
    }

    /**
     * (non-PHPdoc)
     * @see app_db_interface::connect()
     */
    public function connect()
    {
        if (!isset(self::$_mysqli[$this->_use_mirror]))
        {

            mysqli_report(MYSQLI_REPORT_ALL & ~MYSQLI_REPORT_INDEX);

            try {
                self::$_mysqli[$this->_use_mirror] = new mysqli(
                    $this->servers[$this->_use_mirror][0],
                    $this->servers[$this->_use_mirror][1],
                    $this->servers[$this->_use_mirror][2],
                    $this->servers[$this->_use_mirror][3]
                );

                $this->_mysqli()->set_charset(APP_DEFAULT_SQL_CHARSET);

                if (defined("APP_DEVELOPMENT_VERSION") && APP_DEVELOPMENT_VERSION)
                {

                    $this->_mysqli()->query("set profiling = 1;");
                    $this->_mysqli()->query("set @@profiling_history_size = 100;");
                }
            }
            catch(mysqli_sql_exception $e)
            {
                throw new app_exception($e->getMessage(), 503);
            }


        }
        return $this;
    }

    /**
     * (non-PHPdoc)
     * @see app_db_interface::query()
     */
    public function query($query)
    {
        try {

            if ($this->_result instanceof mysqli_result)
            {
                $this->_result->free_result();
            }

            $this->_result = $this->_mysqli()->query($query);
        }
        catch (mysqli_sql_exception $e)
        {
            throw new app_exception("MySQL Query: {$query} <br>\n" . $e->getMessage(), 503);
        }

        return $this;
    }

    /**
     * (non-PHPdoc)
     * @see app_db_interface::rows()
     */
    public function rows()
    {
        if (!$this->_result instanceof mysqli_result)
        {
            return null;
        }

        return $this->_result->num_rows;
    }

    /**
     * (non-PHPdoc)
     * @see app_db_interface::fetch()
     */
    public function fetch()
    {
        if (!$this->_result instanceof mysqli_result)
        {
            return null;
        }

        return $this->_result->fetch_assoc();
    }

    /**
     * (non-PHPdoc)
     * @see app_db_interface::fetch_qualified_array()
     */
    function fetch_qualified_array()
    {
        if (!$this->_result instanceof mysqli_result)
        {
            return null;
        }

        $return = array();

        if ($row = $this->_result->fetch_row())
        {

            $fields = $this->_result->fetch_fields();

            foreach ($row as $_key => $_value)
            {
                $return[ $fields[$_key]->table ][ $fields[$_key]->name ] = $_value;
            }

            return $return;
        }

        return false;
    }

    /**
     * (non-PHPdoc)
     * @see app_db_interface::escape()
     */
    public function escape($string)
    {
        return $this->_mysqli()->real_escape_string($string);
    }

    /**
     * (non-PHPdoc)
     * @see app_db_interface::found_rows()
     */
    public function found_rows()
    {
        if (!$this->_result instanceof mysqli_result)
        {
            return null;
        }
        /* @var $result mysqli_result */
        $result = $this->_mysqli()->query("select found_rows() as `rows`");

        $rows = $result->fetch_row();

        $result->free_result();

        return $rows[0];
    }

    /**
     * (non-PHPdoc)
     * @see app_db_interface::inserted_id()
     */
    public function inserted_id()
    {
        return $this->_mysqli()->insert_id;
    }

    /**
     * Возвращает объект MySQLi
     * @return mysqli
     */
    protected function _mysqli()
    {
        if (!isset(self::$_mysqli[$this->_use_mirror]))
        {
            $this->connect();
        }

        return self::$_mysqli[$this->_use_mirror];
    }

    /**
     * (non-PHPdoc)
     * @see app_db_interface::profiling()
     */
    public function profiling()
    {
        $return = array();

        $result = $this->_mysqli()->query("show profiles;");
        while($row = $result->fetch_object())
        {
            $return[] = $row;
        }

        return $return;
    }
}