/*
 * Copyright (c) 2013 Cisco Systems, Inc. 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.protocol.bgp.rib.impl;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.MoreObjects;
import com.google.common.base.MoreObjects.ToStringHelper;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableSet;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.ExecutionException;
import javax.annotation.Nonnull;
import javax.annotation.concurrent.ThreadSafe;
import org.opendaylight.controller.md.sal.binding.api.DataBroker;
import org.opendaylight.controller.md.sal.binding.api.ReadOnlyTransaction;
import org.opendaylight.controller.md.sal.common.api.data.AsyncTransaction;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
import org.opendaylight.controller.md.sal.common.api.data.TransactionChain;
import org.opendaylight.controller.md.sal.common.api.data.TransactionChainListener;
import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
import org.opendaylight.controller.md.sal.dom.api.DOMDataBroker;
import org.opendaylight.controller.md.sal.dom.api.DOMDataBrokerExtension;
import org.opendaylight.controller.md.sal.dom.api.DOMDataTreeChangeService;
import org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction;
import org.opendaylight.controller.md.sal.dom.api.DOMTransactionChain;
import org.opendaylight.protocol.bgp.mode.api.PathSelectionMode;
import org.opendaylight.protocol.bgp.mode.impl.base.BasePathSelectionModeFactory;
import org.opendaylight.protocol.bgp.openconfig.spi.BGPConfigModuleTracker;
import org.opendaylight.protocol.bgp.openconfig.spi.BGPOpenConfigProvider;
import org.opendaylight.protocol.bgp.rib.DefaultRibReference;
import org.opendaylight.protocol.bgp.rib.impl.spi.BGPDispatcher;
import org.opendaylight.protocol.bgp.rib.impl.spi.CodecsRegistry;
import org.opendaylight.protocol.bgp.rib.impl.spi.RIB;
import org.opendaylight.protocol.bgp.rib.impl.spi.RIBSupportContextRegistry;
import org.opendaylight.protocol.bgp.rib.spi.CacheDisconnectedPeers;
import org.opendaylight.protocol.bgp.rib.spi.RIBExtensionConsumerContext;
import org.opendaylight.protocol.bgp.rib.spi.RibSupportUtils;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.AsNumber;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Address;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.inet.rev150305.bgp.rib.rib.loc.rib.tables.routes.Ipv4RoutesCase;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.inet.rev150305.bgp.rib.rib.loc.rib.tables.routes.Ipv6RoutesCase;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev130919.BgpTableType;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.BgpRib;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.RibId;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.bgp.rib.Rib;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.bgp.rib.RibKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.bgp.rib.rib.LocRib;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.bgp.rib.rib.Peer;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.rib.Tables;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.rib.TablesKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.rib.tables.Routes;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.ClusterIdentifier;
import org.opendaylight.yangtools.binding.data.codec.api.BindingCodecTreeFactory;
import org.opendaylight.yangtools.sal.binding.generator.impl.GeneratedClassLoadingStrategy;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.opendaylight.yangtools.yang.common.QName;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.InstanceIdentifierBuilder;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeIdentifier;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeIdentifierWithPredicates;
import org.opendaylight.yangtools.yang.data.api.schema.ChoiceNode;
import org.opendaylight.yangtools.yang.data.api.schema.ContainerNode;
import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
import org.opendaylight.yangtools.yang.data.impl.schema.Builders;
import org.opendaylight.yangtools.yang.data.impl.schema.ImmutableNodes;
import org.opendaylight.yangtools.yang.data.impl.schema.builder.api.DataContainerNodeBuilder;
import org.opendaylight.yangtools.yang.model.api.SchemaContext;
import org.opendaylight.yangtools.yang.model.api.SchemaContextListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@ThreadSafe
public final class RIBImpl extends DefaultRibReference implements AutoCloseable, RIB, TransactionChainListener, SchemaContextListener {
    private static final Logger LOG = LoggerFactory.getLogger(RIBImpl.class);
    @VisibleForTesting
    public static final QName RIB_ID_QNAME = QName.create(Rib.QNAME, "id").intern();
    @VisibleForTesting
    public static final ContainerNode EMPTY_TABLE_ATTRIBUTES = ImmutableNodes.containerNode(org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.rib.tables.Attributes.QNAME);

    private final BGPDispatcher dispatcher;
    private final DOMTransactionChain domChain;
    private final AsNumber localAs;
    private final Ipv4Address bgpIdentifier;
    private final Set<BgpTableType> localTables;
    private final Set<TablesKey> localTablesKeys;
    private final DataBroker dataBroker;
    private final DOMDataBroker domDataBroker;
    private final RIBExtensionConsumerContext extensions;
    private final YangInstanceIdentifier yangRibId;
    private final RIBSupportContextRegistryImpl ribContextRegistry;
    private final CodecsRegistryImpl codecsRegistry;
    private final DOMDataBrokerExtension service;
    private final List<LocRibWriter> locRibs = new ArrayList<>();
    private final BGPConfigModuleTracker configModuleTracker;
    private final BGPOpenConfigProvider openConfigProvider;
    private final CacheDisconnectedPeers cacheDisconnectedPeers;
    private final Map<TablesKey, PathSelectionMode> bestPathSelectionStrategies;
    private final ImportPolicyPeerTracker importPolicyPeerTracker;

    public RIBImpl(final RibId ribId, final AsNumber localAs, final Ipv4Address localBgpId, final Ipv4Address clusterId, final RIBExtensionConsumerContext extensions,
        final BGPDispatcher dispatcher, final BindingCodecTreeFactory codecFactory,
        final DataBroker dps, final DOMDataBroker domDataBroker, final List<BgpTableType> localTables,
        @Nonnull final Map<TablesKey, PathSelectionMode> bestPathSelectionStrategies, final GeneratedClassLoadingStrategy classStrategy,
        final BGPConfigModuleTracker moduleTracker, final BGPOpenConfigProvider openConfigProvider) {
        super(InstanceIdentifier.create(BgpRib.class).child(Rib.class, new RibKey(Preconditions.checkNotNull(ribId))));
        this.domChain = domDataBroker.createTransactionChain(this);
        this.localAs = Preconditions.checkNotNull(localAs);
        this.bgpIdentifier = Preconditions.checkNotNull(localBgpId);
        this.dispatcher = Preconditions.checkNotNull(dispatcher);
        this.localTables = ImmutableSet.copyOf(localTables);
        this.localTablesKeys = new HashSet<>();
        this.dataBroker = dps;
        this.domDataBroker = Preconditions.checkNotNull(domDataBroker);
        this.extensions = Preconditions.checkNotNull(extensions);
        this.codecsRegistry = CodecsRegistryImpl.create(codecFactory, classStrategy);
        this.ribContextRegistry = RIBSupportContextRegistryImpl.create(extensions, this.codecsRegistry);
        final InstanceIdentifierBuilder yangRibIdBuilder = YangInstanceIdentifier.builder().node(BgpRib.QNAME).node(Rib.QNAME);
        this.yangRibId = yangRibIdBuilder.nodeWithKey(Rib.QNAME, RIB_ID_QNAME, ribId.getValue()).build();
        this.configModuleTracker = moduleTracker;
        this.openConfigProvider = openConfigProvider;
        this.cacheDisconnectedPeers = new CacheDisconnectedPeersImpl();
        this.bestPathSelectionStrategies = Preconditions.checkNotNull(bestPathSelectionStrategies);

        LOG.debug("Instantiating RIB table {} at {}", ribId, this.yangRibId);

        final ContainerNode bgpRib = Builders.containerBuilder()
            .withNodeIdentifier(new NodeIdentifier(BgpRib.QNAME))
                .addChild(ImmutableNodes.mapNodeBuilder(Rib.QNAME).build()).build();

        final MapEntryNode ribInstance = Builders.mapEntryBuilder().withNodeIdentifier(
                new NodeIdentifierWithPredicates(Rib.QNAME, RIB_ID_QNAME, ribId.getValue()))
                    .addChild(ImmutableNodes.leafNode(RIB_ID_QNAME, ribId.getValue()))
                    .addChild(ImmutableNodes.mapNodeBuilder(Peer.QNAME).build())
                    .addChild(Builders.containerBuilder().withNodeIdentifier(new NodeIdentifier(LocRib.QNAME))
                    .addChild(ImmutableNodes.mapNodeBuilder(Tables.QNAME).build())
                    .build()).build();


        final DOMDataWriteTransaction trans = this.domChain.newWriteOnlyTransaction();

        // merge empty BgpRib + Rib, to make sure the top-level parent structure is present
        trans.merge(LogicalDatastoreType.OPERATIONAL, YangInstanceIdentifier.builder().node(BgpRib.QNAME).build(), bgpRib);
        trans.put(LogicalDatastoreType.OPERATIONAL, yangRibIdBuilder.build(), ribInstance);

        try {
            trans.submit().checkedGet();
        } catch (final TransactionCommitFailedException e) {
            LOG.error("Failed to initiate RIB {}", this.yangRibId, e);
        }
        final ClusterIdentifier cId = (clusterId == null) ? new ClusterIdentifier(localBgpId) : new ClusterIdentifier(clusterId);
        final PolicyDatabase policyDatabase  = new PolicyDatabase(localAs.getValue(), localBgpId, cId);
        this.importPolicyPeerTracker = new ImportPolicyPeerTracker(policyDatabase);

        final DOMDataBrokerExtension domDatatreeChangeService = this.domDataBroker.getSupportedExtensions().get(DOMDataTreeChangeService.class);
        this.service = domDatatreeChangeService;
        LOG.debug("Effective RIB created.");

        for (final BgpTableType t : this.localTables) {
            final TablesKey key = new TablesKey(t.getAfi(), t.getSafi());
            this.localTablesKeys.add(key);
            startLocRib(key, policyDatabase);
        }

        if (this.configModuleTracker != null) {
            this.configModuleTracker.onInstanceCreate();
        }
    }

    public RIBImpl(final RibId ribId, final AsNumber localAs, final Ipv4Address localBgpId, final Ipv4Address clusterId, final RIBExtensionConsumerContext extensions,
            final BGPDispatcher dispatcher, final BindingCodecTreeFactory codecFactory,
            final DataBroker dps, final DOMDataBroker domDataBroker, final List<BgpTableType> localTables,
            final Map<TablesKey, PathSelectionMode> bestPathSelectionstrategies, final GeneratedClassLoadingStrategy classStrategy) {
        this(ribId, localAs, localBgpId, clusterId, extensions, dispatcher, codecFactory,
                dps, domDataBroker, localTables, bestPathSelectionstrategies, classStrategy, null, null);
    }

    private void startLocRib(final TablesKey key, final PolicyDatabase pd) {
        LOG.debug("Creating LocRib table for {}", key);
        // create locRibWriter for each table
        final DOMDataWriteTransaction tx = this.domChain.newWriteOnlyTransaction();

        final DataContainerNodeBuilder<NodeIdentifierWithPredicates, MapEntryNode> table = ImmutableNodes.mapEntryBuilder();
        table.withNodeIdentifier(RibSupportUtils.toYangTablesKey(key));
        table.withChild(EMPTY_TABLE_ATTRIBUTES);

        final NodeIdentifierWithPredicates tableKey = RibSupportUtils.toYangTablesKey(key);
        final InstanceIdentifierBuilder tableId = YangInstanceIdentifier.builder(this.yangRibId.node(LocRib.QNAME).node(Tables.QNAME));
        tableId.nodeWithKey(tableKey.getNodeType(), tableKey.getKeyValues());
        for (final Entry<QName, Object> e : tableKey.getKeyValues().entrySet()) {
            table.withChild(ImmutableNodes.leafNode(e.getKey(), e.getValue()));
        }

        final ChoiceNode routes = this.ribContextRegistry.getRIBSupportContext(key).getRibSupport().emptyRoutes();
        table.withChild(routes);

        tx.put(LogicalDatastoreType.OPERATIONAL, tableId.build(), table.build());
        try {
            tx.submit().checkedGet();
        } catch (final TransactionCommitFailedException e1) {
            LOG.error("Failed to initiate LocRIB for key {}", key, e1);
        }

        PathSelectionMode pathSelectionStrategy = this.bestPathSelectionStrategies.get(key);
        if (pathSelectionStrategy == null) {
            pathSelectionStrategy = BasePathSelectionModeFactory.createBestPathSelectionStrategy();
        }
        this.locRibs.add(LocRibWriter.create(this.ribContextRegistry, key, createPeerChain(this), getYangRibId(), this.localAs, getService(), pd,
            this.cacheDisconnectedPeers, pathSelectionStrategy));
    }

    @Override
    public String toString() {
        return addToStringAttributes(MoreObjects.toStringHelper(this)).toString();
    }

    protected ToStringHelper addToStringAttributes(final ToStringHelper toStringHelper) {
        return toStringHelper;
    }

    @Override
    public synchronized void close() throws InterruptedException, ExecutionException {
        final DOMDataWriteTransaction t = this.domChain.newWriteOnlyTransaction();
        t.delete(LogicalDatastoreType.OPERATIONAL, getYangRibId());
        t.submit().get();
        this.domChain.close();
        for (final LocRibWriter locRib : this.locRibs) {
            try {
                locRib.close();
            } catch (final Exception e) {
                LOG.warn("Could not close LocalRib reference: {}", locRib, e);
            }
        }
        if (this.configModuleTracker != null) {
            this.configModuleTracker.onInstanceClose();
        }
    }

    @Override
    public AsNumber getLocalAs() {
        return this.localAs;
    }

    @Override
    public Ipv4Address getBgpIdentifier() {
        return this.bgpIdentifier;
    }

    @Override
    public Set<? extends BgpTableType> getLocalTables() {
        return this.localTables;
    }

    @Override
    public BGPDispatcher getDispatcher() {
        return this.dispatcher;
    }

    @Override
    public void onTransactionChainFailed(final TransactionChain<?, ?> chain, final AsyncTransaction<?, ?> transaction, final Throwable cause) {
        LOG.error("Broken chain in RIB {} transaction {}", getInstanceIdentifier(), transaction != null ? transaction.getIdentifier() : null, cause);
    }

    @Override
    public void onTransactionChainSuccessful(final TransactionChain<?, ?> chain) {
        LOG.info("RIB {} closed successfully", getInstanceIdentifier());
    }

    @Override
    public long getRoutesCount(final TablesKey key) {
        try (final ReadOnlyTransaction tx = this.dataBroker.newReadOnlyTransaction()) {
            final Optional<Tables> tableMaybe = tx.read(LogicalDatastoreType.OPERATIONAL,
                    getInstanceIdentifier().child(LocRib.class).child(Tables.class, key)).checkedGet();
            if (tableMaybe.isPresent()) {
                final Tables table = tableMaybe.get();
                return countIpRoutes(table.getRoutes());
            }
        } catch (final ReadFailedException e) {
            LOG.debug("Failed to read tables", e);
        }
        return 0;
    }

    private int countIpRoutes(final Routes routes) {
        if (routes instanceof Ipv4RoutesCase) {
            final Ipv4RoutesCase routesCase = (Ipv4RoutesCase) routes;
            if (routesCase.getIpv4Routes() != null && routesCase.getIpv4Routes().getIpv4Route() != null) {
                return routesCase.getIpv4Routes().getIpv4Route().size();
            }
        } else if (routes instanceof Ipv6RoutesCase) {
            final Ipv6RoutesCase routesCase = (Ipv6RoutesCase) routes;
            if (routesCase.getIpv6Routes() != null && routesCase.getIpv6Routes().getIpv6Route() != null) {
                return routesCase.getIpv6Routes().getIpv6Route().size();
            }
        }
        return 0;
    }

    public Set<TablesKey> getLocalTablesKeys() {
        return this.localTablesKeys;
    }

    @Override
    public DOMDataTreeChangeService getService() {
        return (DOMDataTreeChangeService) this.service;
    }

    @Override
    public YangInstanceIdentifier getYangRibId() {
        return this.yangRibId;
    }

    @Override
    public DOMTransactionChain createPeerChain(final TransactionChainListener listener) {
        return this.domDataBroker.createTransactionChain(listener);
    }

    @Override
    public RIBExtensionConsumerContext getRibExtensions() {
        return this.extensions;
    }

    @Override
    public RIBSupportContextRegistry getRibSupportContext() {
        return this.ribContextRegistry;
    }

    @Override
    public void onGlobalContextUpdated(final SchemaContext context) {
        this.codecsRegistry.onSchemaContextUpdated(context);
    }

    @Override
    public CodecsRegistry getCodecsRegistry() {
        return this.codecsRegistry;
    }

    @Override
    public Optional<BGPOpenConfigProvider> getOpenConfigProvider() {
        return Optional.fromNullable(this.openConfigProvider);
    }

    @Override
    public CacheDisconnectedPeers getCacheDisconnectedPeers() {
        return this.cacheDisconnectedPeers;
    }

    public ImportPolicyPeerTracker getImportPolicyPeerTracker() {
        return this.importPolicyPeerTracker;
    }
}