/*
 * Copyright (c) 2016 Cisco and/or its affiliates.
 *
 * 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 io.fd.honeycomb.vpp.distro;

import com.google.inject.Inject;
import io.fd.honeycomb.infra.distro.ProviderTrait;
import java.io.IOException;
import org.openvpp.jvpp.JVppRegistry;
import org.openvpp.jvpp.JVppRegistryImpl;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Provides JVppRegistry. Must be a singleton due to shutdown hook usage. Registers shutdown hook to disconnect from
 * VPP.
 */
public final class JVppRegistryProvider extends ProviderTrait<JVppRegistry> {

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

    @Inject
    private VppConfigAttributes config;

    @Override
    protected JVppRegistryImpl create() {
        try {
            final JVppRegistryImpl registry = new JVppRegistryImpl(config.jvppConnectionName);

            // Closing JVpp connection with shutdown hook to erase the connection from VPP so HC will be able
            // to connect next time. If JVM is force closed, this will not be executed and VPP connection
            // with name from config will stay open and prevent next startup of HC to success
            Runtime.getRuntime().addShutdownHook(new Thread() {
                @Override
                public void run() {
                    LOG.info("Disconnecting from VPP");
                    try {
                        registry.close();
                        LOG.info("Successfully disconnected from VPP as {}", config.jvppConnectionName);
                    } catch (Exception e) {
                        LOG.warn("Unable to properly close jvpp registry", e);
                    }
                }
            });

            LOG.info("JVpp connection opened successfully as: {}", config.jvppConnectionName);
            return registry;
        } catch (IOException e) {
            throw new IllegalStateException("Unable to open VPP management connection", e);
        }
    }
}