/*
 * 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.vpnservice.elan.l2gw.listeners;

import org.opendaylight.controller.md.sal.binding.api.ClusteredDataChangeListener;
import org.opendaylight.controller.md.sal.binding.api.DataBroker;
import org.opendaylight.controller.md.sal.binding.api.DataChangeListener;
import org.opendaylight.controller.md.sal.common.api.data.AsyncDataBroker.DataChangeScope;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.elanmanager.utils.ElanL2GwCacheUtils;
import org.opendaylight.vpnservice.datastoreutils.AsyncClusteredDataChangeListenerBase;
import org.opendaylight.vpnservice.elan.l2gw.utils.ElanL2GatewayUtils;
import org.opendaylight.vpnservice.neutronvpn.api.l2gw.L2GatewayDevice;
import org.opendaylight.vpnservice.utils.hwvtep.HwvtepUtils;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.ovsdb.hwvtep.rev150901.hwvtep.global.attributes.LocalUcastMacs;
import org.opendaylight.yang.gen.v1.urn.opendaylight.vpnservice.elan.rev150602.elan.instances.ElanInstance;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.network.topology.topology.Node;
import org.opendaylight.yangtools.concepts.ListenerRegistration;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.collect.Lists;

/**
 * A listener for Ucast MAC entries that are added/removed to/from an External Device (e.g., TOR).
 *
 * When a Ucast MAC addr appears in the hwvtep's operational DS, that MAC must be populated in DMAC tables in all
 * Elan participating DPNs. ELAN is selected according to field 'tunnel_key' of the Logical Switch to which the new
 * MAC belongs.
 *
 */
public class HwvtepLocalUcastMacListener extends
        AsyncClusteredDataChangeListenerBase<LocalUcastMacs, HwvtepLocalUcastMacListener> implements AutoCloseable {

    private DataBroker broker;
    private ListenerRegistration<DataChangeListener> lstnerRegistration;

    private static final Logger logger = LoggerFactory.getLogger(HwvtepLocalUcastMacListener.class);

    public HwvtepLocalUcastMacListener(DataBroker broker) {
        super(LocalUcastMacs.class, HwvtepLocalUcastMacListener.class);

        this.broker = broker;
        registerListener();
    }

    protected void registerListener() {
        try {
            lstnerRegistration = this.broker.registerDataChangeListener(LogicalDatastoreType.OPERATIONAL,
                    HwvtepUtils.getWildCardPathForLocalUcastMacs(), this, DataChangeScope.SUBTREE);
        } catch (final Exception e) {
            logger.error("Hwvtep LocalUcasMacs DataChange listener registration failed !", e);
            throw new IllegalStateException("Hwvtep LocalUcasMacs DataChange listener registration failed .", e);
        }
    }

    @Override
    public void close() throws Exception {
        if (lstnerRegistration != null) {
            try {
                lstnerRegistration.close();
            } catch (final Exception e) {
                logger.error("Error when cleaning up DataChangeListener.", e);
            }
            lstnerRegistration = null;
        }
    }

    @Override
    protected void remove(InstanceIdentifier<LocalUcastMacs> identifier, LocalUcastMacs macRemoved) {
        String hwvtepNodeId = identifier.firstKeyOf(Node.class).getNodeId().getValue();
        String macAddress = macRemoved.getMacEntryKey().getValue();

        logger.trace("LocalUcastMacs {} removed from {}", macAddress, hwvtepNodeId);

        ElanInstance elan = ElanL2GatewayUtils.getElanInstanceForUcastLocalMac(macRemoved);
        if (elan == null) {
            logger.warn("Could not find ELAN for mac {} being deleted", macAddress);
            return;
        }

        String elanName = elan.getElanInstanceName();
        L2GatewayDevice elanL2GwDevice = ElanL2GwCacheUtils.getL2GatewayDeviceFromCache(elanName, hwvtepNodeId);
        if (elanL2GwDevice == null) {
            logger.warn("Could not find L2GatewayDevice for ELAN: {}, nodeID:{} from cache", elanName, hwvtepNodeId);
            return;
        }

        // Remove MAC from cache
        elanL2GwDevice.removeUcastLocalMac(macRemoved);

        ElanL2GatewayUtils.unInstallL2GwUcastMacFromElan(elan, elanL2GwDevice,
                Lists.newArrayList(macRemoved.getMacEntryKey()));
    }

    @Override
    protected void update(InstanceIdentifier<LocalUcastMacs> identifier, LocalUcastMacs original,
            LocalUcastMacs update) {
        // TODO (eperefr) what can change here?

    }

    @Override
    protected void add(InstanceIdentifier<LocalUcastMacs> identifier, LocalUcastMacs macAdded) {
        String hwvtepNodeId = identifier.firstKeyOf(Node.class).getNodeId().getValue();
        String macAddress = macAdded.getMacEntryKey().getValue();

        logger.trace("LocalUcastMacs {} added to {}", macAddress, hwvtepNodeId);

        ElanInstance elan = ElanL2GatewayUtils.getElanInstanceForUcastLocalMac(macAdded);
        if (elan == null) {
            logger.warn("Could not find ELAN for mac {} being added", macAddress);
            return;
        }

        String elanName = elan.getElanInstanceName();
        L2GatewayDevice elanL2GwDevice = ElanL2GwCacheUtils.getL2GatewayDeviceFromCache(elanName, hwvtepNodeId);
        if (elanL2GwDevice == null) {
            logger.warn("Could not find L2GatewayDevice for ELAN: {}, nodeID:{} from cache", elanName, hwvtepNodeId);
            return;
        }

        // Cache MAC for furthur processing later
        elanL2GwDevice.addUcastLocalMac(macAdded);

        ElanL2GatewayUtils.installL2GwUcastMacInElan(elan, elanL2GwDevice, macAddress);
    }

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

    @Override
    protected ClusteredDataChangeListener getDataChangeListener() {
        return HwvtepLocalUcastMacListener.this;
    }

    @Override
    protected DataChangeScope getDataChangeScope() {
        return DataChangeScope.BASE;
    }
}