Placeholders

<?php

namespace mint\sys\classes;
use mysqli;
use Exception;

/**
 * @property int insert_id
 */
class Query
{
    /** @var \mysqli_result */
    public $handle;

    public function __construct($query)
    {
        $this->handle = $query;
    }

    public function __get($name)
    {
        switch ($name) {
            case 'insert_id':
                return DB::$handle->insert_id;
            default:
                return false;
        }
    }

    /**
     * Выполняет запрос к БД и получает одну запись
     *
     * @return \stdClass|bool
     * @see DB::next()
    */
    public function get()
    {
        if (!$this->handle) return false;
        return $this->handle->fetch_object();
    }

    /**
     * Выполняет запрос к БД и загружает все записи
     *
     * @param callable|null $fn
     * @return array|boolean
     */
    public function getAll($fn = null)
    {
        if ($this->handle) {
            $rows = array();
            while ($row = $this->handle->fetch_object())
                is_callable($fn)
                    ? $fn($row)
                    : $rows[] = $row;
            return is_callable($fn) ? true : $rows;
        }
        else
            return false;
    }
}

class DB
{
    /**
     * @var mysqli
     */
    static public $handle = false;
    /**
     * @static
     * @param  $params array
     * @return bool
     */
    static public function connect($params)
    {
        if (self::$handle = new mysqli('localhost', $params['login'], $params['password']))
        {
            self::$handle->select_db($params['db_name']);
            self::$handle->set_charset('UTF8');
            return true;
        }
        return false;
    }

    /**
     * Возвращает строку в стиле mysql
     *
     * @param string $value
     * @param boolean $q
     * @return string
     */
    public static function str($value, $q = true)
    {
        if ($value === null)
            return 'null';
        else
            return ($q ? '"' : '').self::$handle->real_escape_string($value).($q ? '"' : '');
    }

    public static function sql($query, $args)
    {
        $pattern = '~(\?(?:tbl|t|col|c|set|str|s|int|i|list_int|list|li|l|p)?(?::[a-zA-Z_][a-zA-Z0-9_]*)?)~';
        $array   = preg_split($pattern, $query, null, PREG_SPLIT_DELIM_CAPTURE);
        $out     = '';

        if (key($args) === 0)
        {
            $mode = 'numeric';

            $anum  = count($args);
            $pnum  = floor(count($array) / 2);
            if ( $pnum != $anum )
            {
                throw new Exception("Number of args ($anum) doesn't match number of placeholders ($pnum) in [$query]");
            }
        }
        else {
            $mode = 'named';
        }

        static $escape;
        if (!$escape) {
            $escape = array(
                'tbl' => function($data) {
                    return "`$data`";
                },
                'col' => function($data) {
                    return "`$data`";
                },
                'p' => function($data) {
                    return is_null($data) ? '' : $data;
                },
                'str' => function($data) {
                    return is_null($data) ? 'null' : DB::str($data);
                },
                'int' => function($data) {
                    if (is_null($data)) {
                        return 'null';
                    }

                    $data = str_replace(',', '.', $data);
                    if (!is_numeric($data)) {
                        throw new Exception("Integer (?i) placeholder expects numeric value, ".gettype($data)." given");
                    }
                    else {
                        return number_format($data, 0, '.', ''); // may lose precision on big numbers
                    }
                },
                'set' => function($data) use(&$escape)
                {
                    $fv = array();
                    foreach ($data as $key=>$value) {
                        if ($value === '') $value = '""';
                        elseif (is_null($value)) $value = 'null';
                        elseif (is_bool($value)) $value = $value ? 1 : 0;
                        elseif (is_numeric($value)) $value = number_format($value, 0, '.', '');
                        elseif (is_array($value)) {
                            $flag = key($value);
                            $value = $escape[$flag]($value[$flag]);
                        }
                        else $value = DB::str($value);
                        $fv[] = "`$key`=$value";
                    }
                    return implode(',', $fv);
                },
                'list' => function($data) use(&$escape)
                {
                    foreach ($data as $key=>$value)
                    {
                        $data[$key] = $escape['str']($value);
                    }
                    return implode(',', $data);
                },
                'list_int' => function($data) use(&$escape)
                {
                    foreach ($data as $key=>$value)
                    {
                        $data[$key] = $escape['int']($value);
                    }
                    return implode(',', $data);
                },
            );
            $escape['t'] = $escape['tbl'];
            $escape['c'] = $escape['col'];
            $escape['s'] = $escape['str'];
            $escape['i'] = $escape['int'];
            $escape['l'] = $escape['list'];
            $escape['li'] = $escape['list_int'];
        }

        foreach ($array as $i => $part)
        {
            if ( ($i % 2) == 0 )
            {
                $out .= $part;
                continue;
            }

            if ($mode === 'numeric')
            {
                $type  = $part;
                $value = array_shift($args);
            }
            else
            {
                list($type, $key) = explode(':', $part);

                if (array_key_exists($key, $args))
                {
                    $value = $args[$key];
                }
                else {
                    throw new Exception("No key found for the named placeholder [$key] in the data array");
                }
            }

            $type  = trim($type, '?');
            $out .= $escape[$type ? : 'str']($value);
        }
        return $out;
    }

    /**
     * Выполняет запрос к БД.
     *
     * @param string $sql
     * @param array|null $args
     * @return bool|Query
     */
    public static function query($sql, $args = null)
    {
        if ($args) {
            $sql = self::sql($sql, $args);
        }
        if ($query = self::$handle->query($sql))
        {
            $query = new Query($query);
        }
        else {
            trigger_error(self::$handle->error, E_USER_WARNING);
        }

        return $query;
    }
}