tdlib-session-container/src/main/java/it/tdlight/reactiveapi/AtomixReactiveApiMultiClient.java

package it.tdlight.reactiveapi;

import io.atomix.cluster.messaging.ClusterEventService;
import io.atomix.cluster.messaging.MessagingException;
import io.atomix.cluster.messaging.Subscription;
import it.tdlight.jni.TdApi;
import it.tdlight.reactiveapi.Event.ClientBoundEvent;
import it.tdlight.reactiveapi.Event.Request;
import java.time.Duration;
import java.time.Instant;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import reactor.core.publisher.BufferOverflowStrategy;
import reactor.core.publisher.Flux;
import reactor.core.publisher.FluxSink.OverflowStrategy;
import reactor.core.publisher.Mono;
import reactor.core.scheduler.Schedulers;

public class AtomixReactiveApiMultiClient implements ReactiveApiMultiClient, AutoCloseable {

	private final ClusterEventService eventService;
	private final KafkaConsumer kafkaConsumer;
	private final String subGroupId;

	private volatile boolean closed = false;

	AtomixReactiveApiMultiClient(AtomixReactiveApi api, KafkaConsumer kafkaConsumer, String subGroupId) {
		this.eventService = api.getAtomix().getEventService();
		this.kafkaConsumer = kafkaConsumer;
		this.subGroupId = subGroupId;
	}

	@Override
	public Flux<ClientBoundEvent> clientBoundEvents(boolean ack) {
		if (closed) {
			return Flux.empty();
		}
		return kafkaConsumer.consumeMessages(subGroupId, ack).takeUntil(s -> closed);
	}

	@Override
	public <T extends TdApi.Object> Mono<T> request(long userId, long liveId, TdApi.Function<T> request, Instant timeout) {
		return Mono.fromCompletionStage(() -> {
			if (closed) {
				return CompletableFuture.failedFuture(new TdError(500, "Session is closed"));
			}
			return eventService.send("session-" + liveId + "-requests",
					new Request<>(liveId, request, timeout),
					LiveAtomixReactiveApiClient::serializeRequest,
					LiveAtomixReactiveApiClient::deserializeResponse,
					Duration.between(Instant.now(), timeout)
			);
		}).subscribeOn(Schedulers.boundedElastic()).<T>handle((item, sink) -> {
			if (item instanceof TdApi.Error error) {
				sink.error(new TdError(error.code, error.message));
			} else {
				//noinspection unchecked
				sink.next((T) item);
			}
		}).onErrorMap(ex -> {
			if (ex instanceof MessagingException.NoRemoteHandler) {
				return new TdError(404, "Bot #IDU" + userId + " (live id: " + liveId + ") is not found on the cluster");
			} else {
				return ex;
			}
		});
	}

	@Override
	public void close() {
		closed = true;
	}
}