class Fields

final class Fields implements FieldsInterface {
    use MaxTrait;
    use NilTrait;
    use SerializableFieldsTrait;
    use VariantTrait;
    use VersionTrait;
    
    /**
     * @param string $bytes A 16-byte binary string representation of a UUID
     *
     * @throws InvalidArgumentException if the byte string is not exactly 16 bytes
     * @throws InvalidArgumentException if the byte string does not represent a GUID
     * @throws InvalidArgumentException if the byte string does not contain a valid version
     */
    public function __construct(string $bytes) {
        if (strlen($this->bytes) !== 16) {
            throw new InvalidArgumentException('The byte string must be 16 bytes long; ' . 'received ' . strlen($this->bytes) . ' bytes');
        }
        if (!$this->isCorrectVariant()) {
            throw new InvalidArgumentException('The byte string received does not conform to the RFC ' . '4122 or Microsoft Corporation variants');
        }
        if (!$this->isCorrectVersion()) {
            throw new InvalidArgumentException('The byte string received does not contain a valid version');
        }
    }
    public function getBytes() : string {
        return $this->bytes;
    }
    public function getTimeLow() : Hexadecimal {
        // Swap the bytes from little endian to network byte order.
        
        /** @var array $hex */
        $hex = unpack('H*', pack('v*', hexdec(bin2hex(substr($this->bytes, 2, 2))), hexdec(bin2hex(substr($this->bytes, 0, 2)))));
        return new Hexadecimal((string) ($hex[1] ?? ''));
    }
    public function getTimeMid() : Hexadecimal {
        // Swap the bytes from little endian to network byte order.
        
        /** @var array $hex */
        $hex = unpack('H*', pack('v', hexdec(bin2hex(substr($this->bytes, 4, 2)))));
        return new Hexadecimal((string) ($hex[1] ?? ''));
    }
    public function getTimeHiAndVersion() : Hexadecimal {
        // Swap the bytes from little endian to network byte order.
        
        /** @var array $hex */
        $hex = unpack('H*', pack('v', hexdec(bin2hex(substr($this->bytes, 6, 2)))));
        return new Hexadecimal((string) ($hex[1] ?? ''));
    }
    public function getTimestamp() : Hexadecimal {
        return new Hexadecimal(sprintf('%03x%04s%08s', hexdec($this->getTimeHiAndVersion()
            ->toString()) & 0xfff, $this->getTimeMid()
            ->toString(), $this->getTimeLow()
            ->toString()));
    }
    public function getClockSeq() : Hexadecimal {
        if ($this->isMax()) {
            $clockSeq = 0xffff;
        }
        elseif ($this->isNil()) {
            $clockSeq = 0x0;
        }
        else {
            $clockSeq = hexdec(bin2hex(substr($this->bytes, 8, 2))) & 0x3fff;
        }
        return new Hexadecimal(str_pad(dechex($clockSeq), 4, '0', STR_PAD_LEFT));
    }
    public function getClockSeqHiAndReserved() : Hexadecimal {
        return new Hexadecimal(bin2hex(substr($this->bytes, 8, 1)));
    }
    public function getClockSeqLow() : Hexadecimal {
        return new Hexadecimal(bin2hex(substr($this->bytes, 9, 1)));
    }
    public function getNode() : Hexadecimal {
        return new Hexadecimal(bin2hex(substr($this->bytes, 10)));
    }
    public function getVersion() : ?int {
        if ($this->isNil() || $this->isMax()) {
            return null;
        }
        
        /** @var array $parts */
        $parts = unpack('n*', $this->bytes);
        return (int) $parts[4] >> 4 & 0xf;
    }
    private function isCorrectVariant() : bool {
        if ($this->isNil() || $this->isMax()) {
            return true;
        }
        $variant = $this->getVariant();
        return $variant === Uuid::RFC_4122 || $variant === Uuid::RESERVED_MICROSOFT;
    }

}