water/server/app/miniapi/support/PhoneNumber.php

<?php

declare(strict_types=1);

namespace app\miniapi\support;

/** Shared telephone format policy. Format validation does not verify ownership or reachability. */
final class PhoneNumber
{
    public static function normalize(string $phone): string
    {
        $phone = trim($phone);
        if (!preg_match('/^\+?(?:[0-9 -]|\([0-9]+\))+$/D', $phone)) {
            throw new \InvalidArgumentException('联系电话格式无效');
        }
        $normalized = str_replace([' ', '-', '(', ')'], '', $phone);
        $pattern = str_starts_with($normalized, '+') ? '/^\+[1-9][0-9]{6,14}$/D' : '/^[0-9]{7,15}$/D';
        if (!preg_match($pattern, $normalized) || preg_match('/^0+$/D', $normalized)) {
            throw new \InvalidArgumentException('联系电话须包含7至15位数字');
        }

        return $normalized;
    }

    public static function mask(string $phone): string
    {
        if (trim($phone) === '') {
            return '';
        }
        try {
            $normalized = self::normalize($phone);
        } catch (\InvalidArgumentException) {
            // Historical unrecognized values must never fall back to plaintext.
            return '****';
        }
        $prefix = str_starts_with($normalized, '+') ? '+' : '';
        $digits = ltrim($normalized, '+');
        $length = strlen($digits);
        $visibleStart = $length >= 10 ? 3 : 2;
        $visibleEnd = $length >= 10 ? 4 : 2;

        return $prefix . substr($digits, 0, $visibleStart)
            . str_repeat('*', $length - $visibleStart - $visibleEnd)
            . substr($digits, -$visibleEnd);
    }
}