/*
 * Copyright 2014-2019 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package de.codecentric.boot.admin.server.services;

import java.util.Map;
import java.util.logging.Level;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.http.MediaType;
import org.springframework.web.reactive.function.client.ClientResponse;
import reactor.core.publisher.Mono;

import de.codecentric.boot.admin.server.domain.entities.Instance;
import de.codecentric.boot.admin.server.domain.entities.InstanceRepository;
import de.codecentric.boot.admin.server.domain.values.Endpoint;
import de.codecentric.boot.admin.server.domain.values.Info;
import de.codecentric.boot.admin.server.domain.values.InstanceId;
import de.codecentric.boot.admin.server.web.client.InstanceWebClient;

import static de.codecentric.boot.admin.server.utils.MediaType.ACTUATOR_V2_MEDIATYPE;

/**
 * The StatusUpdater is responsible for updating the status of all or a single application
 * querying the healthUrl.
 *
 * @author Johannes Edmeier
 */
public class InfoUpdater {

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

	private static final ParameterizedTypeReference<Map<String, Object>> RESPONSE_TYPE = new ParameterizedTypeReference<Map<String, Object>>() {
	};

	private final InstanceRepository repository;

	private final InstanceWebClient instanceWebClient;

	public InfoUpdater(InstanceRepository repository, InstanceWebClient instanceWebClient) {
		this.repository = repository;
		this.instanceWebClient = instanceWebClient;
	}

	public Mono<Void> updateInfo(InstanceId id) {
		return this.repository.computeIfPresent(id, (key, instance) -> this.doUpdateInfo(instance)).then();
	}

	protected Mono<Instance> doUpdateInfo(Instance instance) {
		if (instance.getStatusInfo().isOffline() || instance.getStatusInfo().isUnknown()) {
			return Mono.empty();
		}
		if (!instance.getEndpoints().isPresent(Endpoint.INFO)) {
			return Mono.empty();
		}

		log.debug("Update info for {}", instance);
		return this.instanceWebClient.instance(instance).get().uri(Endpoint.INFO).exchange()
				.log(log.getName(), Level.FINEST).flatMap((response) -> convertInfo(instance, response))
				.onErrorResume((ex) -> Mono.just(convertInfo(instance, ex))).map(instance::withInfo);
	}

	protected Mono<Info> convertInfo(Instance instance, ClientResponse response) {
		if (response.statusCode().is2xxSuccessful() && response.headers().contentType().map(
				(mt) -> mt.isCompatibleWith(MediaType.APPLICATION_JSON) || mt.isCompatibleWith(ACTUATOR_V2_MEDIATYPE))
				.orElse(false)) {
			return response.bodyToMono(RESPONSE_TYPE).map(Info::from).defaultIfEmpty(Info.empty());
		}
		log.info("Couldn't retrieve info for {}: {}", instance, response.statusCode());
		return response.releaseBody().then(Mono.just(Info.empty()));
	}

	protected Info convertInfo(Instance instance, Throwable ex) {
		log.warn("Couldn't retrieve info for {}", instance, ex);
		return Info.empty();
	}

}
