package eu.eudat.logic.utilities.circuitbreaker;

import eu.eudat.logic.utilities.interfaces.CheckedSupplier;
import org.apache.commons.lang3.StringUtils;
import org.springframework.http.HttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestClientResponseException;

import java.util.*;
import java.util.function.Consumer;

/**
 * Created by ikalyvas on 2/25/2019.
 */
@Component
public class CircuitBreaker {
	private Set<Circuit> circuits = new HashSet<>();
	private Map<Circuit, Consumer<HttpRequest>> resolvers = new HashMap<>();

	public <R> R handle(HttpRequest request, CheckedSupplier<R> function) throws RestClientResponseException {
		Optional<Circuit> circuitOptional = this.circuits.stream()
				.filter(circuit ->
						circuit.getMethod().equals(request.getMethod().name()) && circuit.getUrl().equals(request.getURI().toString()))
				.findFirst();
		if (circuitOptional.isPresent() && circuitOptional.get().isOpen()) {
			Consumer<HttpRequest> resolver = resolvers.get(circuitOptional.get());
			if (resolver != null) {
				resolver.accept(request);
				return null;
			} else throw new RuntimeException("Resolver not found for " + request);
		} else {
			try {
				return function.get();
			} catch (Exception ex) {
				if (circuitOptional.isPresent()) circuitOptional.get().addFailure();
				else
					circuits.add(new Circuit.CircuitBuilder().method(request.getMethod().name()).url(request.getURI().toString()).build());
				throw new RestClientResponseException(StringUtils.EMPTY, 400, StringUtils.EMPTY, null, null, null);
			}
		}
	}

	public CircuitBreaker addCircuitResolver(Circuit circuit, Consumer<HttpRequest> requestConsumer) {
		this.resolvers.put(circuit, requestConsumer);
		return this;
	}
}