/*
 * Copyright (c) 2015 - 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.vpnmanager;

import java.util.ArrayList;
import java.util.List;
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;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.fibmanager.rev150330.FibEntries;
import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.fibmanager.rev150330.fibentries.VrfTables;
import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.fibmanager.rev150330.fibentries.VrfTablesKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.fibmanager.rev150330.vrfentries.VrfEntry;
import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.vpn.instance.op.data.VpnInstanceOpDataEntry;
import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.vpn.instance.op.data.VpnInstanceOpDataEntryBuilder;
import org.opendaylight.yangtools.concepts.ListenerRegistration;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class FibEntriesListener extends AbstractDataChangeListener<VrfEntry> implements AutoCloseable {
    private static final Logger LOG = LoggerFactory.getLogger(FibEntriesListener.class);
    private ListenerRegistration<DataChangeListener> listenerRegistration;
    private final DataBroker dataBroker;
    private final VpnInstanceListener vpnInstanceListener;

    public FibEntriesListener(final DataBroker dataBroker, final VpnInstanceListener vpnInstanceListener) {
        super(VrfEntry.class);
        this.dataBroker = dataBroker;
        this.vpnInstanceListener = vpnInstanceListener;
    }

    public void start() {
        LOG.info("{} start", getClass().getSimpleName());
        listenerRegistration = dataBroker.registerDataChangeListener(LogicalDatastoreType.OPERATIONAL,
                getWildCardPath(), this, AsyncDataBroker.DataChangeScope.BASE);
    }

    private InstanceIdentifier<VrfEntry> getWildCardPath() {
        return InstanceIdentifier.create(FibEntries.class).child(VrfTables.class).child(VrfEntry.class);
    }

    @Override
    public void close() throws Exception {
        if (listenerRegistration != null) {
            listenerRegistration.close();
            listenerRegistration = null;
        }
        LOG.info("{} close", getClass().getSimpleName());
    }

    @Override
    protected void remove(InstanceIdentifier<VrfEntry> identifier,
                          VrfEntry del) {
        LOG.trace("Remove Fib event - Key : {}, value : {} ", identifier, del);
        final VrfTablesKey key = identifier.firstKeyOf(VrfTables.class, VrfTablesKey.class);
        String rd = key.getRouteDistinguisher();
        Long label = del.getLabel();
        VpnInstanceOpDataEntry vpnInstanceOpData = vpnInstanceListener.getVpnInstanceOpData(rd);
        if(vpnInstanceOpData != null) {
            List<Long> routeIds = vpnInstanceOpData.getRouteEntryId();
            if(routeIds == null) {
                LOG.debug("Fib Route entry is empty.");
                return;
            }
            LOG.debug("Removing label from vpn info - {}", label);
            routeIds.remove(label);
            TransactionUtil.asyncWrite(dataBroker, LogicalDatastoreType.OPERATIONAL,
                    VpnUtil.getVpnInstanceOpDataIdentifier(rd),
                    new VpnInstanceOpDataEntryBuilder(vpnInstanceOpData).setRouteEntryId(routeIds).build(),
                    TransactionUtil.DEFAULT_CALLBACK);
        } else {
            LOG.warn("No VPN Instance found for RD: {}", rd);
        }
    }

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

    }

    @Override
    protected void add(InstanceIdentifier<VrfEntry> identifier,
                       VrfEntry add) {
        LOG.trace("Add Vrf Entry event - Key : {}, value : {}", identifier, add);
        final VrfTablesKey key = identifier.firstKeyOf(VrfTables.class, VrfTablesKey.class);
        String rd = key.getRouteDistinguisher();
        Long label = add.getLabel();
        VpnInstanceOpDataEntry vpn = vpnInstanceListener.getVpnInstanceOpData(rd);
        if(vpn != null) {
            List<Long> routeIds = vpn.getRouteEntryId();
            if(routeIds == null) {
                routeIds = new ArrayList<>();
            }
            LOG.debug("Adding label to vpn info - {}", label);
            routeIds.add(label);
            TransactionUtil.asyncWrite(dataBroker, LogicalDatastoreType.OPERATIONAL,
                    VpnUtil.getVpnInstanceOpDataIdentifier(rd),
                    new VpnInstanceOpDataEntryBuilder(vpn).setRouteEntryId(routeIds).build(),
                    TransactionUtil.DEFAULT_CALLBACK);
        } else {
            LOG.warn("No VPN Instance found for RD: {}", rd);
        }
    }
}