/*
 * Copyright (c) 2016 Ericsson India Global Services Pvt Ltd. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */
package org.opendaylight.netvirt.elan.l2gw.listeners;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import javax.annotation.PostConstruct;
import javax.inject.Inject;
import javax.inject.Singleton;
import org.opendaylight.controller.md.sal.binding.api.DataBroker;
import org.opendaylight.controller.md.sal.binding.api.ReadWriteTransaction;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
import org.opendaylight.genius.datastoreutils.AsyncClusteredDataTreeChangeListenerBase;
import org.opendaylight.netvirt.elan.l2gw.utils.L2GatewayConnectionUtils;
import org.opendaylight.netvirt.elan.utils.ElanClusterUtils;
import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.elan.rev150602.ElanInstances;
import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.elan.rev150602.elan.instances.ElanInstance;
import org.opendaylight.yang.gen.v1.urn.opendaylight.neutron.l2gateways.rev150712.l2gateway.connections.attributes.L2gatewayConnections;
import org.opendaylight.yang.gen.v1.urn.opendaylight.neutron.l2gateways.rev150712.l2gateway.connections.attributes.l2gatewayconnections.L2gatewayConnection;
import org.opendaylight.yang.gen.v1.urn.opendaylight.neutron.rev150712.Neutron;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@Singleton
public class ElanInstanceListener extends AsyncClusteredDataTreeChangeListenerBase<ElanInstance,
        ElanInstanceListener> {

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

    private final DataBroker broker;
    private final ElanClusterUtils elanClusterUtils;
    private static final Map<String, List<Runnable>> WAITING_JOB_LIST = new ConcurrentHashMap<>();

    @Inject
    public ElanInstanceListener(final DataBroker db, final ElanClusterUtils elanClusterUtils) {
        super(ElanInstance.class, ElanInstanceListener.class);
        broker = db;
        this.elanClusterUtils = elanClusterUtils;
    }

    @PostConstruct
    public void init() {
        registerListener(LogicalDatastoreType.CONFIGURATION, broker);
    }

    @Override
    protected void remove(final InstanceIdentifier<ElanInstance> identifier,
                          final ElanInstance del) {
        elanClusterUtils.runOnlyInOwnerNode(del.getElanInstanceName(), "delete Elan instance",
            () -> {
                LOG.info("Elan instance {} deleted from Configuration tree ", del);
                List<L2gatewayConnection> connections =
                        L2GatewayConnectionUtils.getL2GwConnectionsByElanName(
                                this.broker, del.getElanInstanceName());
                if (connections == null || connections.isEmpty()) {
                    return null;
                }
                try {
                    ReadWriteTransaction tx = this.broker.newReadWriteTransaction();
                    for (L2gatewayConnection connection : connections) {
                        InstanceIdentifier<L2gatewayConnection> iid = InstanceIdentifier.create(Neutron.class)
                            .child(L2gatewayConnections.class).child(L2gatewayConnection.class, connection.getKey());
                        tx.delete(LogicalDatastoreType.CONFIGURATION, iid);
                    }
                    tx.submit().checkedGet();
                } catch (TransactionCommitFailedException e) {
                    LOG.error("Failed to delete associated l2gwconnection while deleting network", e);
                }
                return null;
            });
    }

    @Override
    protected void update(InstanceIdentifier<ElanInstance> identifier, ElanInstance original, ElanInstance update) {

    }

    @Override
    protected void add(InstanceIdentifier<ElanInstance> identifier, ElanInstance add) {
        List<Runnable> runnables = WAITING_JOB_LIST.get(add.getElanInstanceName());
        if (runnables != null) {
            runnables.forEach(Runnable::run);
        }
    }

    public static void runJobAfterElanIsAvailable(String elanName, Runnable runnable) {
        WAITING_JOB_LIST.computeIfAbsent(elanName, (name) -> new ArrayList<>());
        WAITING_JOB_LIST.get(elanName).add(runnable);
    }

    @Override
    protected ElanInstanceListener getDataTreeChangeListener() {
        return ElanInstanceListener.this;
    }

    @Override
    protected InstanceIdentifier<ElanInstance> getWildCardPath() {
        return InstanceIdentifier.create(ElanInstances.class).child(ElanInstance.class);
    }

}