final class Loop
{
    /**
     * @var object
     */
    private $counter;

    /**
     * @var bool
     */
    private $first;

    public function __construct()
    {
        $this->reset();
    }

    public function reset()
    {
        $this->counter = $this->getCounter();
        $this->first = true;
    }

    public function onFirst(callable $callable, ...$args)
    {
        $return = $this->incrementAndReturn($this->first, $callable, ...$args);
        $this->first = false;
        return $return;
    }

    public function onNth(int $n, callable $callable, ...$args)
    {
        return $this->incrementAndReturn($this->counter->count() === $n, $callable, ...$args);
    }

    public function onOdd(callable $callable, ...$args)
    {
        return $this->incrementAndReturn($this->counter->mod(2) !== 0, $callable, ...$args);
    }

    public function onEven(callable $callable, ...$args)
    {
        return $this->incrementAndReturn($this->counter->mod(2) === 0, $callable, ...$args);
    }

    private function incrementAndReturn(bool $condition, callable $callable, ...$args)
    {
        try {
            if ($condition) {
                return ($callable)(...$args);
            }
        } finally {
            $this->counter->inc();
        }
    }

    private static function getCounter()
    {
        return new class
        {
            private $count = 1;

            public function inc()
            {
                $this->count++;
            }

            public function mod($i)
            {
                return $this->count % $i;
            }

            public function count()
            {
                return $this->count;
            }
        };
    }
}