/*
 * 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.dhcpservice;

import java.math.BigInteger;

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.mdsalutil.MDSALUtil;
import org.opendaylight.vpnservice.neutronvpn.api.l2gw.L2GatewayDevice;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.IpAddress;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.ovsdb.hwvtep.rev150901.HwvtepGlobalAugmentation;
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.params.xml.ns.yang.ovsdb.hwvtep.rev150901.hwvtep.global.attributes.LogicalSwitches;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.NetworkTopology;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.NodeId;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.network.topology.Topology;
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.base.Optional;

public class DhcpUCastMacListener extends AsyncClusteredDataChangeListenerBase<LocalUcastMacs, DhcpUCastMacListener> implements AutoCloseable {

    private static final Logger logger = LoggerFactory.getLogger(DhcpUCastMacListener.class);
    private DataBroker broker;
    private ListenerRegistration<DataChangeListener> listenerRegistration;
    private DhcpExternalTunnelManager dhcpExternalTunnelManager;

    public DhcpUCastMacListener(DhcpExternalTunnelManager dhcpManager, DataBroker dataBroker) {
        super(LocalUcastMacs.class, DhcpUCastMacListener.class);
        this.broker = dataBroker;
        this.dhcpExternalTunnelManager = dhcpManager;
    }

    @Override
    protected InstanceIdentifier<LocalUcastMacs> getWildCardPath() {
        return InstanceIdentifier.create(NetworkTopology.class).child(Topology.class).child(Node.class)
                .augmentation(HwvtepGlobalAugmentation.class).child(LocalUcastMacs.class);
    }

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

    @Override
    protected void remove(InstanceIdentifier<LocalUcastMacs> identifier,
            LocalUcastMacs del) {
        // Flow removal for table 18 is handled in Neutron Port delete.
    }

    @Override
    protected void update(InstanceIdentifier<LocalUcastMacs> identifier,
            LocalUcastMacs original, LocalUcastMacs update) {
        // TODO Auto-generated method stub

    }

    @Override
    protected void add(InstanceIdentifier<LocalUcastMacs> identifier,
            LocalUcastMacs add) {
        NodeId torNodeId = identifier.firstKeyOf(Node.class).getNodeId();
        InstanceIdentifier<LogicalSwitches> logicalSwitchRef = (InstanceIdentifier<LogicalSwitches>) add.getLogicalSwitchRef().getValue();
        Optional<LogicalSwitches> logicalSwitchOptional = MDSALUtil.read(broker, LogicalDatastoreType.OPERATIONAL, logicalSwitchRef);
        if ( !logicalSwitchOptional.isPresent() ) {
            logger.error("Logical Switch ref doesn't have data {}", logicalSwitchRef);
            return;
        }
        LogicalSwitches logicalSwitch = logicalSwitchOptional.get();
        String elanInstanceName = logicalSwitch.getHwvtepNodeName().getValue();
        L2GatewayDevice device = ElanL2GwCacheUtils.getL2GatewayDeviceFromCache(elanInstanceName, torNodeId.getValue());
        if (device == null) {
            logger.error("Logical Switch Device with name {} is not present in L2GWCONN cache", elanInstanceName);
            return;
        }
        IpAddress tunnelIp = device.getTunnelIp();
        BigInteger designatedDpnId = dhcpExternalTunnelManager.readDesignatedSwitchesForExternalTunnel(tunnelIp, elanInstanceName);
        dhcpExternalTunnelManager.installDhcpFlowsForVms(tunnelIp, elanInstanceName, DhcpServiceUtils.getListOfDpns(broker), designatedDpnId, add.getMacEntryKey().getValue());
    }

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

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