class RandomIdGenerator

class RandomIdGenerator implements IdGeneratorInterface {
    private const TRACE_ID_HEX_LENGTH = 32;
    private const SPAN_ID_HEX_LENGTH = 16;
    public function generateTraceId() : string {
        do {
            $traceId = $this->randomHex(self::TRACE_ID_HEX_LENGTH);
        } while (!SpanContextValidator::isValidTraceId($traceId));
        return $traceId;
    }
    public function generateSpanId() : string {
        do {
            $spanId = $this->randomHex(self::SPAN_ID_HEX_LENGTH);
        } while (!SpanContextValidator::isValidSpanId($spanId));
        return $spanId;
    }
    
    /**
     * @psalm-suppress ArgumentTypeCoercion $hexLength is always a positive integer
     */
    private function randomHex(int $hexLength) : string {
        try {
            return bin2hex(random_bytes(intdiv($hexLength, 2)));
        } catch (Throwable) {
            return $this->fallbackAlgorithm($hexLength);
        }
    }
    private function fallbackAlgorithm(int $hexLength) : string {
        return substr(str_shuffle(str_repeat('0123456789abcdef', $hexLength)), 1, $hexLength);
    }

}