// src/Billing/TariffCalculator.php
class TariffCalculator
{
    private static TariffConfig $config;
    private static array $cache = [];

    public static function init(array $rawConfig): void
    {
        self::$config = new TariffConfig($rawConfig);
    }

    public static function calculate(int $userId, int $units): float
    {
        $key = $userId . ':' . $units;

        if (isset(self::$cache[$key])) {
            return self::$cache[$key];
        }

        $price = self::$config->getBasePrice()
            * $units
            * self::$config->getUserMultiplier($userId);

        self::$cache[$key] = $price;

        return $price;
    }

    public static function resetCache(): void
    {
        self::$cache = [];
    }
}

// src/Billing/TariffConfig.php
class TariffConfig
{
    private float $basePrice;
    private array $multipliers;

    public function __construct(array $config)
    {
        $this->basePrice   = (float) $config['base_price'];
        $this->multipliers = $config['multipliers'] ?? [];
    }

    public function getBasePrice(): float
    {
        return $this->basePrice;
    }

    public function getUserMultiplier(int $userId): float
    {
        return $this->multipliers[$userId] ?? 1.0;
    }
}

// bootstrap.php — вызывается один раз при старте воркера
TariffCalculator::init(loadConfigFromDB());

// Где-то в обработчике запроса
$price = TariffCalculator::calculate($user->id, $request->units);