<?php
namespace Acme;

$int_filter = function($value) {
    if (!preg_match('/\A(?:0|[1-9][0-9]*)\z/', (string)$value)) {
        throw new \InvalidArgumentException('invalid unsigned integer.');
    }
    return (int)$value;
};

$length_checker = function($value, $min = null, $max = null) {
    $length = mb_strlen($value);
    if (isset($min) && $length < $min) {
        throw new \InvalidArgumentException(
            sprintf('character length must not less than %s.', $min));
    }
    if (isset($max) && $length > $max) {
        throw new \InvalidArgumentException(
            sprintf('character length must not greater than %s.', $max));
    }
    return $value;
};

$sanitizer = function($value) {
    return preg_replace('/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]+/S', '', $value);
};

$normalize_newline = function($value) {
    return str_replace("\r", "\n", str_replace("\r\n", "\n", $value));
};

$user = FilterableAccessor::instance(array(
    'number' => function($value) use ($int_filter) {
        return $int_filter($value);
    },
    'name' => function($value) use ($length_checker, $sanitizer) {
        return $length_checker(
            $sanitizer($value), 1, 10);
    },
    'comment' => function($value) use ($length_checker, $sanitizer, $normalize_newline) {
        return $length_checker(
            $normalize_newline(
                $sanitizer($value), null, 50));
    },
));

// プロパティ形式
$user->number = '1';
$user->name = 'Tanaka';
echo '<pre>';
var_dump($user->number); // int(1)
var_dump($user->name); // string(6) "Tanaka"
echo '</pre>';

// メソッド形式
$user->number('2')->name('Suzuki');
echo '<pre>';
var_dump($user->number()); // int(2)
var_dump($user->name()); // string(6) "Suzuki"
echo '</pre>';

// フィルタで制御コードをサニタイズ（←言うな）
$user->name("Holy\x00\x00\x00"); // NULL byte
echo '<pre>';
var_dump($user->name()); // string(4) "Holy"
echo '</pre>';

// フィルタで改行コードを正規化
$user->comment("Hoge\r\nFuga\r\nPiyo\r\n"); // CR+LF newline
echo '<pre>';
var_dump($user->comment()); // string(15) "Hoge\nFuga\nPiyo\n"
echo '</pre>';


// 未定義プロパティへのアクセス
echo '<pre>';
try {
    $user->age = '30';
} catch (\InvalidArgumentException $e) {
    echo $e->getMessage(); //  The property "age" does not exists.
}
echo '</pre>';

// フィルタでチェック
echo '<pre>';
try {
    $user->number = '-1';
} catch (\InvalidArgumentException $e) {
    echo $e->getMessage(); //  The property "number" is not valid : invalid unsigned integer.
}
echo '</pre>';

// フィルタでチェック
echo '<pre>';
try {
    $user->name('VeryVeryLongName');
} catch (\InvalidArgumentException $e) {
    echo $e->getMessage(); //  The property "name" is not valid : character length must not greater than 10.
}
echo '</pre>';