/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.pulsar.broker;

import static org.apache.commons.lang3.StringUtils.isBlank;
import java.net.InetAddress;
import java.net.URI;
import java.net.UnknownHostException;
import java.util.Map;
import java.util.Optional;
import org.apache.pulsar.broker.validator.MultipleListenerValidator;
import org.apache.pulsar.policies.data.loadbalancer.AdvertisedListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ServiceConfigurationUtils {

    private static final Logger LOG = LoggerFactory.getLogger(ServiceConfigurationUtils.class);

    public static String getDefaultOrConfiguredAddress(String configuredAddress) {
        if (isBlank(configuredAddress)) {
            return unsafeLocalhostResolve();
        }
        return configuredAddress;
    }

    public static String unsafeLocalhostResolve() {
        try {
            // Get the fully qualified hostname
            return InetAddress.getLocalHost().getCanonicalHostName();
        } catch (UnknownHostException ex) {
            LOG.error(ex.getMessage(), ex);
            throw new IllegalStateException("Failed to resolve localhost name.", ex);
        }
    }

    /**
     * Get the address of Broker, first try to get it from AdvertisedAddress.
     * If it is not set, try to get the address set by advertisedListener.
     * If it is still not set, get it through InetAddress.getLocalHost().
     * @param configuration
     * @param ignoreAdvertisedListener Sometimes we can’t use the default key of AdvertisedListener,
     *                                 setting it to true can ignore AdvertisedListener.
     * @return
     */
    @Deprecated
    public static String getAppliedAdvertisedAddress(ServiceConfiguration configuration,
                                                     boolean ignoreAdvertisedListener) {
        Map<String, AdvertisedListener> result = MultipleListenerValidator
                .validateAndAnalysisAdvertisedListener(configuration);

        String advertisedAddress = configuration.getAdvertisedAddress();
        if (advertisedAddress != null) {
            return advertisedAddress;
        }

        AdvertisedListener advertisedListener = result.get(configuration.getInternalListenerName());
        if (advertisedListener != null && !ignoreAdvertisedListener) {
            String address = advertisedListener.getBrokerServiceUrl().getHost();
            if (address != null) {
                return address;
            }
        }

        return getDefaultOrConfiguredAddress(advertisedAddress);
    }

    /**
     * Gets the internal advertised listener for broker-to-broker communication.
     * @return a non-null advertised listener
     */
    public static AdvertisedListener getInternalListener(ServiceConfiguration config) {
        Map<String, AdvertisedListener> result = MultipleListenerValidator
                .validateAndAnalysisAdvertisedListener(config);
        AdvertisedListener internal = result.get(config.getInternalListenerName());
        if (internal == null) {
            // synthesize an advertised listener based on legacy configuration properties
            String host = ServiceConfigurationUtils.getDefaultOrConfiguredAddress(config.getAdvertisedAddress());
            internal = AdvertisedListener.builder()
                    .brokerServiceUrl(createUriOrNull("pulsar", host, config.getBrokerServicePort()))
                    .brokerServiceUrlTls(createUriOrNull("pulsar+ssl", host, config.getBrokerServicePortTls()))
                    .build();

        }
        return internal;
    }

    private static URI createUriOrNull(String scheme, String hostname, Optional<Integer> port) {
        return port.map(p -> URI.create(String.format("%s://%s:%d", scheme, hostname, p))).orElse(null);
    }

    /**
     * Gets the web service address (hostname).
     */
    public static String getWebServiceAddress(ServiceConfiguration config) {
        return ServiceConfigurationUtils.getDefaultOrConfiguredAddress(config.getAdvertisedAddress());
    }

    public static String brokerUrl(String host, int port) {
        return String.format("pulsar://%s:%d", host, port);
    }

    public static String brokerUrlTls(String host, int port) {
        return String.format("pulsar+ssl://%s:%d", host, port);
    }

    public static String webServiceUrl(String host, int port) {
        return String.format("http://%s:%d", host, port);
    }

    public static String webServiceUrlTls(String host, int port) {
        return String.format("https://%s:%d", host, port);
    }
}