package at.gv.egiz.moazs.backend;

import at.gv.egiz.moazs.MoaZSException;
import at.gv.egiz.moazs.repository.DeliveryRepository;
import at.gv.egiz.moazs.scheme.MsgResponse;
import at.gv.egiz.moazs.service.MsgService;
import at.gv.zustellung.app2mzs.xsd.MsgResponseSinksType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import java.util.function.Consumer;

import static at.gv.egiz.moazs.MoaZSException.*;
import static java.lang.String.format;
import static java.util.concurrent.CompletableFuture.supplyAsync;

@Component
public class MsgResponseBackend implements Consumer<String> {

    private static final Logger log = LoggerFactory.getLogger(MsgService.class);

    public static final String MOASP_SIGNATURE_INVALID_ERROR_MSG = "Signature of Msg Response " +
            "with AppDeliveryID=%s is not valid.";
    public static final String BINARY_RESPONSE_MISSING_ERROR_MSG = "Binary Response is not in repository.";
    public static final String RESPONSE_MISSING_ERROR_MSG = "Response with ResponseID=%s is not in repository.";

    private final DeliveryRepository repository;
    private final Consumer<byte[]> signatureVerifier;
    private final SaveResponseToFileSink saveResponseSink;
    private final LogResponseSink logResponseSink;
    private final ForwardResponseToServiceSink forwardResponseSink;

    @Autowired
    public MsgResponseBackend(DeliveryRepository repository,
                              Consumer<byte[]> signatureVerifier,
                              SaveResponseToFileSink saveResponseToFileSink,
                              LogResponseSink logResponseSink,
                              ForwardResponseToServiceSink forwardResponseSink) {
        this.repository = repository;
        this.signatureVerifier = signatureVerifier;
        this.saveResponseSink = saveResponseToFileSink;
        this.logResponseSink = logResponseSink;
        this.forwardResponseSink = forwardResponseSink;

    }

    /**
     * Performs all {@code MsgResponse}'s Back-End Tasks, such as verifying
     * its signature and archiving the response.
     *
     * Note: When the signature verification fails, this method will not archive
     * the original response (the one that was received from msg) to the sink,
     * but an error message.
     *
     * @param responseID refers to MsgResponse Object.
     */
    @Override
    public void accept(String responseID) {

        supplyAsync(() -> verify(responseID))
                .thenAcceptAsync(msgResponse -> applySinks(msgResponse))
                .exceptionally(ex -> {
                    log.error(ex.getMessage(), ex);
                    return null;
                });
    }

    private MsgResponse verify(String responseID) {

        var response = repository.retrieveResponse(responseID).orElseThrow(
                ()-> moaZSException(format(RESPONSE_MISSING_ERROR_MSG, responseID)));

        try {
            var binaryResponse = repository.retrieveBinaryResponse(responseID).orElseThrow(
                    () -> moaZSException(BINARY_RESPONSE_MISSING_ERROR_MSG, MoaZSException.ERROR_MZS_BINARY_RESPONSE_MISSING));
            signatureVerifier.accept(binaryResponse);
            return response;
        } catch (MoaZSException ex) {
            log.error(ex.getMessage(), ex);
            var text = format(MOASP_SIGNATURE_INVALID_ERROR_MSG, response.getAppDeliveryID());
            var code = ERROR_MOASP_SIGNATURE_INVALID;
            return response.generateError(text, code);
        }

    }

    private void applySinks(MsgResponse msgResponse) {

        var sinkParams = getSinkParams(msgResponse);

        if (sinkParams.getSaveResponseToFile().isActive()) {
            supplyAsync(() -> saveResponseSink.save(msgResponse, sinkParams.getSaveResponseToFile().getPath()));
        }

        if (sinkParams.isLogResponse()) {
            supplyAsync(() -> logResponseSink.log(msgResponse));
        }

        if (sinkParams.getForwardResponseToService().isActive()) {
            supplyAsync(() -> forwardResponseSink.send(
                    msgResponse, sinkParams.getForwardResponseToService().getMzsClient()));
        }

    }

    private MsgResponseSinksType getSinkParams(MsgResponse msgResponse) {
        var appDeliveryID = msgResponse.getAppDeliveryID();
        var request = repository.retrieveDeliveryRequest(appDeliveryID).get();
        return request.getConfig().getMsgResponseSinks();
    }

}