/*
 * 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 com.google.common.base.Optional;

import com.google.common.util.concurrent.ListenableFuture;
import org.opendaylight.controller.md.sal.binding.api.DataBroker;
import org.opendaylight.controller.md.sal.binding.api.DataChangeListener;
import org.opendaylight.controller.md.sal.binding.api.WriteTransaction;
import org.opendaylight.controller.md.sal.common.api.data.AsyncDataBroker.DataChangeScope;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.genius.datastoreutils.DataStoreJobCoordinator;
import org.opendaylight.netvirt.vpnmanager.utilities.InterfaceUtils;
import org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.vpn.interfaces.VpnInterface;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.iana._if.type.rev140508.Tunnel;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev140508.InterfacesState;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev140508.interfaces.state.Interface;
import org.opendaylight.yang.gen.v1.urn.opendaylight.genius.interfacemanager.rpcs.rev160406.OdlInterfaceRpcService;
import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.router.interfaces.RouterInterface;
import org.opendaylight.yangtools.concepts.ListenerRegistration;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.math.BigInteger;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Callable;

public class InterfaceStateChangeListener extends AbstractDataChangeListener<Interface> implements AutoCloseable {
    private static final Logger LOG = LoggerFactory.getLogger(InterfaceStateChangeListener.class);

    private ListenerRegistration<DataChangeListener> listenerRegistration;
    private final DataBroker broker;
    private VpnInterfaceManager vpnInterfaceManager;
    private OdlInterfaceRpcService interfaceManager;


    public InterfaceStateChangeListener(final DataBroker db, VpnInterfaceManager vpnInterfaceManager) {
        super(Interface.class);
        broker = db;
        this.vpnInterfaceManager = vpnInterfaceManager;
        registerListener(db);
    }

    public void setIfaceMgrRpcService(OdlInterfaceRpcService interfaceManager) {
      this.interfaceManager = interfaceManager;
    }

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


    private void registerListener(final DataBroker db) {
        try {
            listenerRegistration = db.registerDataChangeListener(LogicalDatastoreType.OPERATIONAL,
                                                                 getWildCardPath(), InterfaceStateChangeListener.this, DataChangeScope.SUBTREE);
        } catch (final Exception e) {
            LOG.error("Interface DataChange listener registration failed", e);
            throw new IllegalStateException("Nexthop Manager registration Listener failed.", e);
        }
    }

    @Override
    protected void add(InstanceIdentifier<Interface> identifier, Interface intrf) {
        LOG.trace("Received interface {} add event", intrf);
        try {
            final String interfaceName = intrf.getName();
            LOG.info("Received interface add event for interface {} ", interfaceName);
            org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev140508.interfaces.Interface
                    configInterface = InterfaceUtils.getInterface(broker, interfaceName);
            if (configInterface != null) {
                if (!configInterface.getType().equals(Tunnel.class)) {
                    // We service only VM interfaces and Router interfaces here.
                    // We donot service Tunnel Interfaces here.
                    // Tunnel events are directly serviced
                    // by TunnelInterfacesStateListener present as part of VpnInterfaceManager
                    final VpnInterface vpnInterface = VpnUtil.getConfiguredVpnInterface(broker, interfaceName);
                    if (vpnInterface != null) {
                        final BigInteger dpnId = InterfaceUtils.getDpIdFromInterface(intrf);
                        final int ifIndex = intrf.getIfIndex();
                        DataStoreJobCoordinator dataStoreCoordinator = DataStoreJobCoordinator.getInstance();
                        dataStoreCoordinator.enqueueJob("VPNINTERFACE-" + intrf.getName(),
                                new Callable<List<ListenableFuture<Void>>>() {
                                    @Override
                                    public List<ListenableFuture<Void>> call() throws Exception {
                                        WriteTransaction writeTxn = broker.newWriteOnlyTransaction();
                                        vpnInterfaceManager.processVpnInterfaceUp(dpnId, vpnInterface, ifIndex, false, writeTxn);
                                        List<ListenableFuture<Void>> futures = new ArrayList<>();
                                        futures.add(writeTxn.submit());
                                        return futures;
                                    }
                                });
                    } else {
                        RouterInterface routerInterface = VpnUtil.getConfiguredRouterInterface(broker, interfaceName);
                        if (routerInterface != null) {
                            final String routerName = routerInterface.getRouterName();
                            DataStoreJobCoordinator dataStoreCoordinator = DataStoreJobCoordinator.getInstance();
                            dataStoreCoordinator.enqueueJob("VPNINTERFACE-" + intrf.getName(),
                                    new Callable<List<ListenableFuture<Void>>>() {
                                        @Override
                                        public List<ListenableFuture<Void>> call() throws Exception {
                                            WriteTransaction writeTxn = broker.newWriteOnlyTransaction();
                                            handleRouterInterfacesUpEvent(routerName, interfaceName, writeTxn);
                                            List<ListenableFuture<Void>> futures = new ArrayList<>();
                                            futures.add(writeTxn.submit());
                                            return futures;
                                        }
                                    });
                        } else {
                            LOG.info("Unable to process add for interface {} as it is not configured for vpn", interfaceName);
                        }
                    }
                }
            } else {
                LOG.error("Unable to process add for interface {} ," +
                        "since Interface ConfigDS entry absent for the same", interfaceName);
            }
        } catch (Exception e) {
            LOG.error("Exception caught in Interface Operational State Up event", e);
        }
    }


    private InstanceIdentifier<Interface> getWildCardPath() {
        return InstanceIdentifier.create(InterfacesState.class).child(Interface.class);
    }

    @Override
    protected void remove(InstanceIdentifier<Interface> identifier, Interface intrf) {
        LOG.trace("Received interface {} down event", intrf);
        try {
            final String interfaceName = intrf.getName();
            LOG.info("Received port DOWN event for interface {} ", interfaceName);
            if (intrf != null && intrf.getType() != null && intrf.getType().equals(Tunnel.class)) {
                //withdraw all prefixes in all vpns for this dpn from bgp
                // FIXME: Blocked until tunnel event[vxlan/gre] support is available
                // vpnInterfaceManager.updatePrefixesForDPN(dpId, VpnInterfaceManager.UpdateRouteAction.WITHDRAW_ROUTE);
            } else {
                BigInteger dpId = BigInteger.ZERO;
                InstanceIdentifier<VpnInterface> id = VpnUtil.getVpnInterfaceIdentifier(interfaceName);
                Optional<VpnInterface> optVpnInterface = VpnUtil.read(broker, LogicalDatastoreType.OPERATIONAL, id);
                if (!optVpnInterface.isPresent()) {
                    LOG.debug("Interface {} is not a vpninterface, ignoring.", intrf.getName());
                    return;
                }
                VpnInterface vpnInterface = optVpnInterface.get();
                try {
                    dpId = InterfaceUtils.getDpIdFromInterface(intrf);
                } catch (Exception e){
                    LOG.warn("Unable to retrieve dpnId from interface operational data store for interface {}. Fetching from vpn interface op data store. ", intrf.getName(), e);
                    dpId = vpnInterface.getDpnId();
                }
                final BigInteger dpnId = dpId;
                final int ifIndex = intrf.getIfIndex();
                DataStoreJobCoordinator dataStoreCoordinator = DataStoreJobCoordinator.getInstance();
                dataStoreCoordinator.enqueueJob("VPNINTERFACE-" + intrf.getName(),
                        new Callable<List<ListenableFuture<Void>>>() {
                            @Override
                            public List<ListenableFuture<Void>> call() throws Exception {
                                WriteTransaction writeTxn = broker.newWriteOnlyTransaction();
                                vpnInterfaceManager.processVpnInterfaceDown(dpnId, interfaceName, ifIndex, false, false, writeTxn);
                                RouterInterface routerInterface = VpnUtil.getConfiguredRouterInterface(broker, interfaceName);
                                if (routerInterface != null) {
                                    final String routerName = routerInterface.getRouterName();
                                    handleRouterInterfacesDownEvent(routerName, interfaceName, dpnId, writeTxn);
                                }
                                List<ListenableFuture<Void>> futures = new ArrayList<>();
                                futures.add(writeTxn.submit());
                                return futures;
                            }
                        });
            }
        } catch (Exception e) {
            LOG.error("Exception observed in handling deletion of VPN Interface {}. ", intrf.getName(), e);
        }
    }

    @Override
    protected void update(InstanceIdentifier<Interface> identifier,
                          Interface original, Interface update) {
        LOG.trace("Operation Interface update event - Old: {}, New: {}", original, update);
        final String interfaceName = update.getName();
        if (original.getOperStatus().equals(Interface.OperStatus.Unknown) ||
                update.getOperStatus().equals(Interface.OperStatus.Unknown)){
            LOG.debug("Interface {} state change is from/to UNKNOWN. Ignoring the update event.", interfaceName);
            return;
        }
        final BigInteger dpnId = InterfaceUtils.getDpIdFromInterface(update);
        final int ifIndex = update.getIfIndex();
        if (update != null) {
            if (!update.getType().equals(Tunnel.class)) {
                final VpnInterface vpnInterface = VpnUtil.getConfiguredVpnInterface(broker, interfaceName);
                if (vpnInterface != null) {
                    if (update.getOperStatus().equals(Interface.OperStatus.Up)) {
                        DataStoreJobCoordinator dataStoreCoordinator = DataStoreJobCoordinator.getInstance();
                        dataStoreCoordinator.enqueueJob(interfaceName,
                                new Callable<List<ListenableFuture<Void>>>() {
                                    @Override
                                    public List<ListenableFuture<Void>> call() throws Exception {
                                        WriteTransaction writeTxn = broker.newWriteOnlyTransaction();
                                        vpnInterfaceManager.processVpnInterfaceUp(dpnId, vpnInterface, ifIndex,
                                                true, writeTxn);
                                        List<ListenableFuture<Void>> futures = new ArrayList<>();
                                        futures.add(writeTxn.submit());
                                        return futures;
                                    }
                                });
                    } else if (update.getOperStatus().equals(Interface.OperStatus.Down)) {
                        DataStoreJobCoordinator dataStoreCoordinator = DataStoreJobCoordinator.getInstance();
                        dataStoreCoordinator.enqueueJob(interfaceName,
                                new Callable<List<ListenableFuture<Void>>>() {
                                    @Override
                                    public List<ListenableFuture<Void>> call() throws Exception {
                                        WriteTransaction writeTxn = broker.newWriteOnlyTransaction();
                                        vpnInterfaceManager.processVpnInterfaceDown(dpnId, interfaceName, ifIndex, true, false, writeTxn);
                                        List<ListenableFuture<Void>> futures = new ArrayList<>();
                                        futures.add(writeTxn.submit());
                                        return futures;
                                    }
                                });
                    }
                }
            }
        }
    }

    void handleRouterInterfacesUpEvent(String routerName, String interfaceName, WriteTransaction writeTxn) {
        LOG.debug("Handling UP event for router interface {} in Router {}", interfaceName, routerName);
        vpnInterfaceManager.addToNeutronRouterDpnsMap(routerName, interfaceName, writeTxn);
    }

    void handleRouterInterfacesDownEvent(String routerName, String interfaceName, BigInteger dpnId, WriteTransaction writeTxn) {
        LOG.debug("Handling DOWN event for router interface {} in Router {}", interfaceName, routerName);
        vpnInterfaceManager.removeFromNeutronRouterDpnsMap(routerName, interfaceName, dpnId, writeTxn);
    }

}