/*
 * Copyright (c) 2016 Intel and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.fd.honeycomb.vppnsh.impl.oper;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;

import io.fd.honeycomb.translate.read.ReadContext;
import io.fd.honeycomb.translate.spi.read.ListReaderCustomizer;
import io.fd.honeycomb.translate.read.ReadFailedException;
import io.fd.honeycomb.translate.v3po.util.NamingContext;
import io.fd.honeycomb.translate.v3po.util.TranslateUtils;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.CompletionStage;
import javax.annotation.Nonnull;

import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.vpp.nsh.rev160624.Ethernet;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.vpp.nsh.rev160624.Ipv4;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.vpp.nsh.rev160624.Ipv6;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.vpp.nsh.rev160624.EncapType;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.vpp.nsh.rev160624.VxlanGpe;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.vpp.nsh.rev160624.VppNshStateBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.vpp.nsh.rev160624.vpp.nsh.state.NshMapsBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.vpp.nsh.rev160624.vpp.nsh.state.nsh.maps.NshMap;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.vpp.nsh.rev160624.vpp.nsh.state.nsh.maps.NshMapBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.vpp.nsh.rev160624.vpp.nsh.state.nsh.maps.NshMapKey;
import org.opendaylight.yangtools.concepts.Builder;
import org.opendaylight.yangtools.yang.binding.DataObject;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.openvpp.jvpp.VppBaseCallException;
import org.openvpp.jvpp.nsh.dto.NshMapDump;
import org.openvpp.jvpp.nsh.dto.NshMapDetails;
import org.openvpp.jvpp.nsh.dto.NshMapDetailsReplyDump;
import org.openvpp.jvpp.nsh.future.FutureJVppNsh;
import io.fd.honeycomb.vppnsh.impl.util.FutureJVppNshCustomizer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Reader customizer responsible for nsh map read.<br> to VPP.
 */
public class NshMapReaderCustomizer extends FutureJVppNshCustomizer
    implements ListReaderCustomizer<NshMap, NshMapKey, NshMapBuilder> {

    private static final Logger LOG = LoggerFactory.getLogger(NshMapReaderCustomizer.class);
    private final NamingContext nshMapContext;
    private final NamingContext interfaceContext;

    public NshMapReaderCustomizer(@Nonnull final FutureJVppNsh futureJVppNsh,
                                    @Nonnull final NamingContext nshMapContext,
                                    @Nonnull final NamingContext interfaceContext) {
        super(futureJVppNsh);
        this.nshMapContext = checkNotNull(nshMapContext, "nshMapContext should not be null");
        this.interfaceContext = checkNotNull(interfaceContext, "interfaceContext should not be null");
    }


    @Override
    public void merge(@Nonnull final Builder<? extends DataObject> builder,
                      @Nonnull final List<NshMap> readData) {
        ((NshMapsBuilder) builder).setNshMap(readData);
    }

    @Nonnull
    @Override
    public NshMapBuilder getBuilder(@Nonnull final InstanceIdentifier<NshMap> id) {
        return new NshMapBuilder();
    }

    @Override
    public void readCurrentAttributes(@Nonnull final InstanceIdentifier<NshMap> id,
                    @Nonnull final NshMapBuilder builder, @Nonnull final ReadContext ctx)
                    throws ReadFailedException {
        LOG.debug("Reading attributes for nsh map: {}", id);
        try {
            final NshMapKey key = id.firstKeyOf(NshMap.class);
            checkArgument(key != null, "could not find NshMap key in {}", id);
            final NshMapDump request = new NshMapDump();

            final String mapName = key.getName();
            if (!nshMapContext.containsIndex(mapName, ctx.getMappingContext())) {
                LOG.debug("Could not find nsh map {} in the naming context", mapName);
                return;
            }
            request.mapIndex = nshMapContext.getIndex(mapName, ctx.getMappingContext());

            final CompletionStage<NshMapDetailsReplyDump> nshMapDetailsReplyDumpCompletionStage =
                     getFutureJVppNsh().nshMapDump(request);
            final NshMapDetailsReplyDump reply =
                     TranslateUtils.getReplyForRead(nshMapDetailsReplyDumpCompletionStage.toCompletableFuture(), id);

            if (reply == null || reply.nshMapDetails == null || reply.nshMapDetails.isEmpty()) {
                LOG.debug("Has no Nsh Map {} in VPP. ", key.getName());
                return;
            }

            LOG.trace("Nsh Map : {} attributes returned from VPP: {}", key.getName(), reply);

            final NshMapDetails nshMapDetails = reply.nshMapDetails.get(0);
            builder.setName(mapName);
            builder.setKey(key);

            builder.setNsp( (long)((nshMapDetails.nspNsi>>8) & 0xFFFFFF));
            builder.setNsi( (short)(nshMapDetails.nspNsi & 0xFF ));

            builder.setMappedNsp( (long)((nshMapDetails.mappedNspNsi>>8) & 0xFFFFFF));
            builder.setMappedNsi( (short)(nshMapDetails.mappedNspNsi & 0xFF ));

            switch(nshMapDetails.nextNode) {
            case 2:
                builder.setEncapType(VxlanGpe.class);
                break;
            default:
                LOG.trace("Unsupported encap type for nsh map: {}", nshMapDetails.nextNode);
                return;
            }

            checkState(interfaceContext.containsName(nshMapDetails.swIfIndex, ctx.getMappingContext()),
                    "Mapping does not contains mapping for provider interface Index ");
            final String interfaceName = interfaceContext.getName(nshMapDetails.swIfIndex, ctx.getMappingContext());
            builder.setEncapIfName(interfaceName);

            if (LOG.isTraceEnabled()) {
                LOG.trace("Attributes for nsh map {} successfully read: {}", id, builder.build());
            }
        } catch (VppBaseCallException e) {
            LOG.warn("Failed to readCurrentAttributes for: {}", id);
            throw new ReadFailedException( id, e );
        }
    }

    @Nonnull
    @Override
    public List<NshMapKey> getAllIds(@Nonnull final InstanceIdentifier<NshMap> id,
                                       @Nonnull final ReadContext context) throws ReadFailedException {
        LOG.debug("Reading list of keys for nsh map: {}", id);

        final NshMapDump request = new NshMapDump();
        request.mapIndex = -1; // dump call

        NshMapDetailsReplyDump reply;
        try {
            reply = getFutureJVppNsh().nshMapDump(request).toCompletableFuture().get();
        } catch (Exception e) {
            throw new IllegalStateException("Nsh Map dump failed", e);
        }

        if (reply == null || reply.nshMapDetails == null) {
            return Collections.emptyList();
        }

        final int nIdsLength = reply.nshMapDetails.size();
        LOG.debug("vppstate.NshMapCustomizer.getAllIds: nIds.length={}", nIdsLength);
        if (nIdsLength == 0) {
            return Collections.emptyList();
        }

        final List<NshMapKey> allIds = new ArrayList<>(nIdsLength);
        for (NshMapDetails detail : reply.nshMapDetails) {
            final String nshName = nshMapContext.getName(detail.mapIndex, context.getMappingContext());
            LOG.debug("vppstate.NshMapCustomizer.getAllIds: nName={}", nshName);
            allIds.add(new NshMapKey(nshName));
        }

        return allIds;
    }
}