/*
 * Copyright (c) 2015 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.linkstate;

import com.google.common.base.Optional;
import com.google.common.collect.ImmutableCollection;
import com.google.common.collect.ImmutableSet;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction;
import org.opendaylight.protocol.bgp.linkstate.nlri.LinkstateNlriParser;
import org.opendaylight.protocol.bgp.rib.spi.AbstractRIBSupport;
import org.opendaylight.protocol.util.ByteArray;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.linkstate.rev150210.bgp.rib.rib.loc.rib.tables.routes.LinkstateRoutesCase;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.linkstate.rev150210.linkstate.destination.CLinkstateDestination;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.linkstate.rev150210.linkstate.routes.LinkstateRoutes;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.linkstate.rev150210.linkstate.routes.linkstate.routes.LinkstateRoute;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.linkstate.rev150210.update.attributes.mp.reach.nlri.advertized.routes.destination.type.destination.linkstate._case.DestinationLinkstate;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.rib.tables.Routes;
import org.opendaylight.yangtools.yang.binding.DataObject;
import org.opendaylight.yangtools.yang.common.QName;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
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.YangInstanceIdentifier.PathArgument;
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.DataContainerChild;
import org.opendaylight.yangtools.yang.data.api.schema.DataContainerNode;
import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
import org.opendaylight.yangtools.yang.data.api.schema.UnkeyedListEntryNode;
import org.opendaylight.yangtools.yang.data.api.schema.UnkeyedListNode;
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.DataContainerNodeAttrBuilder;
import org.opendaylight.yangtools.yang.data.impl.schema.builder.api.DataContainerNodeBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

final class LinkstateRIBSupport extends AbstractRIBSupport {
    private static abstract class ApplyRoute {
        abstract void apply(DOMDataWriteTransaction tx, YangInstanceIdentifier base, NodeIdentifierWithPredicates routeKey, DataContainerNode<?> route, final ContainerNode attributes);
    }

    private static final class DeleteRoute extends ApplyRoute {
        @Override
        void apply(final DOMDataWriteTransaction tx, final YangInstanceIdentifier base, final NodeIdentifierWithPredicates routeKey, final DataContainerNode<?> route, final ContainerNode attributes) {
            tx.delete(LogicalDatastoreType.OPERATIONAL, base.node(routeKey));
        }
    }

    private final class PutRoute extends ApplyRoute {
        @Override
        void apply(final DOMDataWriteTransaction tx, final YangInstanceIdentifier base, final NodeIdentifierWithPredicates routeKey,
            final DataContainerNode<?> route, final ContainerNode attributes) {
            final DataContainerNodeBuilder<NodeIdentifierWithPredicates, MapEntryNode> b = ImmutableNodes.mapEntryBuilder();
            b.withNodeIdentifier(routeKey);

            // FIXME: All route children, there should be a utility somewhere to do this
            for (final DataContainerChild<? extends PathArgument, ?> child : route.getValue()) {
                b.withChild(child);
            }
            // Add attributes
            final DataContainerNodeAttrBuilder<NodeIdentifier, ContainerNode> cb = Builders.containerBuilder(attributes);
            cb.withNodeIdentifier(routeAttributesIdentifier());
            b.withChild(cb.build());
            tx.put(LogicalDatastoreType.OPERATIONAL, base.node(routeKey), b.build());
        }
    }

    private static final Logger LOG = LoggerFactory.getLogger(LinkstateRIBSupport.class);

    private static final QName ROUTE_KEY = QName.cachedReference(QName.create(LinkstateRoute.QNAME, "route-key"));
    private static final LinkstateRIBSupport SINGLETON = new LinkstateRIBSupport();
    private static final ApplyRoute DELETE_ROUTE = new DeleteRoute();

    private final ChoiceNode emptyRoutes = Builders.choiceBuilder()
        .withNodeIdentifier(new NodeIdentifier(Routes.QNAME))
        .addChild(Builders.containerBuilder()
            .withNodeIdentifier(new NodeIdentifier(LinkstateRoutes.QNAME))
            .addChild(ImmutableNodes.mapNodeBuilder(LinkstateRoute.QNAME).build()).build()).build();
    private final NodeIdentifier destination = new NodeIdentifier(DestinationLinkstate.QNAME);
    private final NodeIdentifier route = new NodeIdentifier(LinkstateRoute.QNAME);
    private final NodeIdentifier nlriRoutesList = new NodeIdentifier(CLinkstateDestination.QNAME);
    private final ApplyRoute putRoute = new PutRoute();

    private LinkstateRIBSupport() {
       super(LinkstateRoutesCase.class, LinkstateRoutes.class, LinkstateRoute.class);
    }

    static LinkstateRIBSupport getInstance() {
        return SINGLETON;
    }

    @Override
    public ChoiceNode emptyRoutes() {
        return this.emptyRoutes;
    }

    @Override
    public ImmutableCollection<Class<? extends DataObject>> cacheableAttributeObjects() {
        return ImmutableSet.of();
    }

    @Override
    public ImmutableCollection<Class<? extends DataObject>> cacheableNlriObjects() {
        return ImmutableSet.of();
    }

    @Override
    protected void deleteDestinationRoutes(final DOMDataWriteTransaction tx, final YangInstanceIdentifier tablePath,
        final ContainerNode destination) {
        processDestination(tx, tablePath, destination, null, DELETE_ROUTE);
    }

    private void processDestination(final DOMDataWriteTransaction tx, final YangInstanceIdentifier tablePath,
        final ContainerNode destination, final ContainerNode attributes, final ApplyRoute function) {
        if (destination != null) {
            final Optional<DataContainerChild<? extends PathArgument, ?>> maybeRoutes = destination.getChild(this.nlriRoutesList);
            if (maybeRoutes.isPresent()) {
                final DataContainerChild<? extends PathArgument, ?> routes = maybeRoutes.get();
                if (routes instanceof UnkeyedListNode) {
                    final YangInstanceIdentifier base = tablePath.node(ROUTES).node(routesContainerIdentifier()).node(this.route);
                    for (final UnkeyedListEntryNode e : ((UnkeyedListNode)routes).getValue()) {
                        final NodeIdentifierWithPredicates routeKey = createRouteKey(e);
                        function.apply(tx, base, routeKey,  e, attributes);
                    }
                } else {
                    LOG.warn("Routes {} are not a map", routes);
                }
            }
        }
    }

    @Override
    protected void putDestinationRoutes(final DOMDataWriteTransaction tx, final YangInstanceIdentifier tablePath,
        final ContainerNode destination, final ContainerNode attributes) {
        processDestination(tx, tablePath, destination, attributes, this.putRoute);
    }

    private NodeIdentifierWithPredicates createRouteKey(final UnkeyedListEntryNode linkstate) {
        final ByteBuf buffer = Unpooled.buffer();
        LinkstateNlriParser.serializeNlri(linkstate, buffer);
        return new NodeIdentifierWithPredicates(LinkstateRoute.QNAME, ROUTE_KEY, ByteArray.readAllBytes(buffer));
    }

    @Override
    protected NodeIdentifier destinationContainerIdentifier() {
        return this.destination;
    }
}