class SimpleSpanProcessor

class SimpleSpanProcessor implements SpanProcessorInterface {
    use LogsMessagesTrait;
    private ContextInterface $exportContext;
    private bool $running = false;
    
    /** @var SplQueue<array{Closure, string, bool, ContextInterface}> */
    private SplQueue $queue;
    private bool $closed = false;
    public function __construct(SpanExporterInterface $exporter) {
        $this->exportContext = Context::getCurrent();
        $this->queue = new SplQueue();
    }
    public function onStart(ReadWriteSpanInterface $span, ContextInterface $parentContext) : void {
    }
    public function onEnd(ReadableSpanInterface $span) : void {
        if ($this->closed) {
            return;
        }
        if (!$span->getContext()
            ->isSampled()) {
            return;
        }
        $spanData = $span->toSpanData();
        $this->flush(fn() => $this->exporter
            ->export([
            $spanData,
        ])
            ->await(), 'export', false, $this->exportContext);
    }
    public function forceFlush(?CancellationInterface $cancellation = null) : bool {
        if ($this->closed) {
            return false;
        }
        return $this->flush(fn(): bool => $this->exporter
            ->forceFlush($cancellation), __FUNCTION__, true, Context::getCurrent());
    }
    public function shutdown(?CancellationInterface $cancellation = null) : bool {
        if ($this->closed) {
            return false;
        }
        $this->closed = true;
        return $this->flush(fn(): bool => $this->exporter
            ->shutdown($cancellation), __FUNCTION__, true, Context::getCurrent());
    }
    private function flush(Closure $task, string $taskName, bool $propagateResult, ContextInterface $context) : bool {
        $this->queue
            ->enqueue([
            $task,
            $taskName,
            $propagateResult && !$this->running,
            $context,
        ]);
        if ($this->running) {
            return false;
        }
        $success = true;
        $exception = null;
        $this->running = true;
        try {
            while (!$this->queue
                ->isEmpty()) {
                [
                    $task,
                    $taskName,
                    $propagateResult,
                    $context,
                ] = $this->queue
                    ->dequeue();
                $scope = $context->activate();
                try {
                    $result = $task();
                    if ($propagateResult) {
                        $success = $result;
                    }
                } catch (Throwable $e) {
                    if ($propagateResult) {
                        $exception = $e;
                    }
                    else {
                        self::logError(sprintf('Unhandled %s error', $taskName), [
                            'exception' => $e,
                        ]);
                    }
                } finally {
                    $scope->detach();
                }
            }
        } finally {
            $this->running = false;
        }
        if ($exception !== null) {
            throw $exception;
        }
        return $success;
    }

}