package it.tdlight.reactiveapi;

import io.atomix.cluster.messaging.ClusterEventService;
import io.atomix.core.Atomix;
import it.tdlight.jni.TdApi;
import it.tdlight.reactiveapi.Event.ClientBoundEvent;
import it.tdlight.reactiveapi.Event.OnBotLoginCodeRequested;
import it.tdlight.reactiveapi.Event.OnOtherDeviceLoginRequested;
import it.tdlight.reactiveapi.Event.OnPasswordRequested;
import it.tdlight.reactiveapi.Event.OnUpdateData;
import it.tdlight.reactiveapi.Event.OnUpdateError;
import it.tdlight.reactiveapi.Event.OnUserLoginCodeRequested;
import it.tdlight.reactiveapi.Event.Request;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.time.Duration;
import java.time.Instant;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.lang3.SerializationException;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import reactor.core.scheduler.Schedulers;

public class LiveAtomixReactiveApiClient implements ReactiveApiClient {

	private final ClusterEventService eventService;
	private final long liveId;
	private final long userId;

	private final Flux<ClientBoundEvent> clientBoundEvents;

	LiveAtomixReactiveApiClient(Atomix atomix, KafkaConsumer kafkaConsumer, long liveId, long userId) {
		this.eventService = atomix.getEventService();
		this.liveId = liveId;
		this.userId = userId;
		this.clientBoundEvents = kafkaConsumer.consumeMessages(kafkaConsumer.newRandomGroupId(), true, userId, liveId).share();
	}

	@Override
	public Flux<ClientBoundEvent> clientBoundEvents() {
		return clientBoundEvents;
	}
	
	@Override
	public <T extends TdApi.Object> Mono<T> request(TdApi.Function<T> request, Instant timeout) {
		return Mono
				.fromCompletionStage(() -> eventService.send("session-" + liveId + "-requests",
						new Request<>(liveId, request, timeout),
						LiveAtomixReactiveApiClient::serializeRequest,
						LiveAtomixReactiveApiClient::deserializeResponse,
						Duration.between(Instant.now(), timeout)
				))
				.subscribeOn(Schedulers.boundedElastic())
				.handle((item, sink) -> {
					if (item instanceof TdApi.Error error) {
						sink.error(new TdError(error.code, error.message));
					} else {
						//noinspection unchecked
						sink.next((T) item);
					}
				});
	}

	@Override
	public long getUserId() {
		return userId;
	}

	static TdApi.Object deserializeResponse(byte[] bytes) {
		try {
			return TdApi.Deserializer.deserialize(new DataInputStream(new ByteArrayInputStream(bytes)));
		} catch (IOException ex) {
			throw new SerializationException(ex);
		}
	}

	static byte[] serializeRequest(Request<?> request) {
		try (var byteArrayOutputStream = new ByteArrayOutputStream()) {
			try (var dataOutputStream = new DataOutputStream(byteArrayOutputStream)) {
				dataOutputStream.writeLong(request.liveId());
				dataOutputStream.writeLong(request.timeout().toEpochMilli());
				request.request().serialize(dataOutputStream);
				dataOutputStream.flush();
				return byteArrayOutputStream.toByteArray();
			}
		} catch (UnsupportedOperationException | IOException ex) {
			throw new SerializationException(ex);
		}
	}

	static ClientBoundEvent deserializeEvent(byte[] bytes) {
		try (var byteArrayInputStream = new ByteArrayInputStream(bytes)) {
			try (var is = new DataInputStream(byteArrayInputStream)) {
				return deserializeEvent(is);
			}
		} catch (IOException ex) {
			throw new SerializationException(ex);
		}
	}

	static List<ClientBoundEvent> deserializeEvents(byte[] bytes) {
		try (var byteArrayInputStream = new ByteArrayInputStream(bytes)) {
			try (var is = new DataInputStream(byteArrayInputStream)) {
				var len = is.readInt();
				var result = new ArrayList<ClientBoundEvent>(len);
				for (int i = 0; i < len; i++) {
					result.add(deserializeEvent(is));
				}
				return result;
			}
		} catch (IOException ex) {
			throw new SerializationException(ex);
		}
	}

	static ClientBoundEvent deserializeEvent(DataInputStream is) throws IOException {
		var liveId = is.readLong();
		var userId = is.readLong();
		return switch (is.readByte()) {
			case 0x01 -> new OnUpdateData(liveId, userId, (TdApi.Update) TdApi.Deserializer.deserialize(is));
			case 0x02 -> new OnUpdateError(liveId, userId, (TdApi.Error) TdApi.Deserializer.deserialize(is));
			case 0x03 -> new OnUserLoginCodeRequested(liveId, userId, is.readLong());
			case 0x04 -> new OnBotLoginCodeRequested(liveId, userId, is.readUTF());
			case 0x05 -> new OnOtherDeviceLoginRequested(liveId, userId, is.readUTF());
			case 0x06 -> new OnPasswordRequested(liveId, userId, is.readUTF(), is.readBoolean(), is.readUTF());
			default -> throw new IllegalStateException("Unexpected value: " + is.readByte());
		};
	}
}