#include <librdkafka/rdkafkacpp.h>

#include <condition_variable>

#include <unistd.h>

static void check(RdKafka::Conf::ConfResult result, const std::string& errString) {

	if (result != RdKafka::Conf::CONF_OK) {

		throw std::logic_error("Unable to configure Kafka: " + errString);

	}

}

static void check(RdKafka::ErrorCode result, const std::string& errString) {

	if (result != RdKafka::ERR_NO_ERROR) {

		throw std::logic_error("Kafka error: " + errString);

	}

}

static void check(std::shared_ptr<RdKafka::KafkaConsumer> kafkaConsumer, const std::string& errString) {

	if (kafkaConsumer.get() == nullptr) {

		throw std::logic_error("Unable to create Kafka consumer: " + errString);

	}

}

	std::string errString;

	std::shared_ptr<RdKafka::Conf> consumerConf(RdKafka::Conf::create(RdKafka::Conf::ConfType::CONF_GLOBAL));

	// TODO: configurable groupId, clientId and other parameters

	std::string groupId = "relpipe-in-kafka-group-" + std::to_string(getpid());

	std::string clientId = "relpipe-in-kafka-client-" + std::to_string(getpid());

	check(consumerConf->set("client.id", clientId, errString), errString);

	check(consumerConf->set("group.id", groupId, errString), errString);

	check(consumerConf->set("bootstrap.servers", "plaintext://127.0.0.1:9092", errString), errString);

	//check(consumerConf->set("auto.offset.reset", "earliest", errString), errString);

	//check(consumerConf->set("debug", "all", errString), errString);

	std::shared_ptr<RdKafka::KafkaConsumer> kafkaConsumer(RdKafka::KafkaConsumer::create(consumerConf.get(), errString));

	check(kafkaConsumer, errString);

	check(kafkaConsumer->subscribe({"relpipe"}), errString);

	for (int i = configuration.messageCount; continueProcessing && i > 0;) {

		shared_ptr<RdKafka::Message> message(kafkaConsumer->consume(100));

		if (message.get() && message->err() == 0) {

			std::string payload = message->payload() ? std::string((const char*) message->payload(), message->len()) : std::string("");

			writer->writeAttribute(convertor.from_bytes(message->topic_name()));

			writer->writeAttribute(Hex::toTxt(payload));

			writer->writeAttribute(Hex::toHex(payload));

			i--;

		} else if (message->err() == RdKafka::ErrorCode::ERR__TIMED_OUT) {

			// timeout → try again

		} else if (message->err() == RdKafka::ErrorCode::ERR__PARTITION_EOF) {

			// reached the end of the topic/partition → try again

		} else {

			std::string m = "error while reading message: " + (message.get() ? message->errstr() : "message is missing");

			writer->writeAttribute(configuration.queue);

			writer->writeAttribute(Hex::toTxt(m));

			writer->writeAttribute(Hex::toHex(m));

			break;

		}

	// TODO: wrap and close even on exception

	check(kafkaConsumer->close(), errString);