/*
 * Copyright (c) 2016 Cisco 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.nat.read.ifc;

import io.fd.honeycomb.translate.read.ReadContext;
import io.fd.honeycomb.translate.spi.read.Initialized;
import io.fd.honeycomb.translate.util.read.cache.DumpCacheManager;
import io.fd.honeycomb.translate.vpp.util.NamingContext;
import io.fd.vpp.jvpp.snat.dto.SnatInterfaceDetails;
import io.fd.vpp.jvpp.snat.dto.SnatInterfaceDetailsReplyDump;
import javax.annotation.Nonnull;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev140508.Interfaces;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev140508.interfaces.Interface;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev140508.interfaces.InterfaceKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang._interface.nat.rev161214.NatInterfaceAugmentation;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang._interface.nat.rev161214._interface.nat.attributes.Nat;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang._interface.nat.rev161214._interface.nat.attributes.NatBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang._interface.nat.rev161214._interface.nat.attributes.nat.Inbound;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang._interface.nat.rev161214._interface.nat.attributes.nat.InboundBuilder;
import org.opendaylight.yangtools.concepts.Builder;
import org.opendaylight.yangtools.yang.binding.Augmentation;
import org.opendaylight.yangtools.yang.binding.DataContainer;
import org.opendaylight.yangtools.yang.binding.DataObject;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

final class InterfaceInboundNatCustomizer extends AbstractInterfaceNatCustomizer<Inbound, InboundBuilder> {

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

    InterfaceInboundNatCustomizer(
            @Nonnull final DumpCacheManager<SnatInterfaceDetailsReplyDump, Void> dumpMgr,
            @Nonnull final NamingContext ifcContext) {
        super(dumpMgr, ifcContext);
    }

    @Override
    protected Logger getLog() {
        return LOG;
    }

    @Override
    void setBuilderPresence(@Nonnull final InboundBuilder builder) {
        ((PresenceInboundBuilder) builder).setPresent(true);
    }

    @Override
    boolean isExpectedNatType(final SnatInterfaceDetails snatInterfaceDetails) {
        return snatInterfaceDetails.isInside == 1;
    }

    @Nonnull
    @Override
    public InboundBuilder getBuilder(@Nonnull final InstanceIdentifier<Inbound> id) {
        // Return not present value by default
        return new PresenceInboundBuilder(false);
    }

    @Override
    public void merge(@Nonnull final Builder<? extends DataObject> parentBuilder, @Nonnull final Inbound readValue) {
        ((NatBuilder) parentBuilder).setInbound(readValue);
    }

    @Nonnull
    @Override
    public Initialized<? extends DataObject> init(@Nonnull final InstanceIdentifier<Inbound> id,
                                                  @Nonnull final Inbound readValue,
                                                  @Nonnull final ReadContext ctx) {
        final InstanceIdentifier<Inbound> cfgId =
                InstanceIdentifier.create(Interfaces.class)
                .child(Interface.class,
                        new InterfaceKey(id.firstKeyOf(
                        org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev140508.interfaces.state.Interface.class).getName()))
                .augmentation(NatInterfaceAugmentation.class)
                .child(Nat.class)
                .child(Inbound.class);
        return Initialized.create(cfgId, readValue);
    }

    // TODO HONEYCOMB-270, make this better, having to fake a builder + value is just exploitation.

    /**
     * Special Builder to also propagate empty container into the resulting data.
     */
    private static final class PresenceInboundBuilder extends InboundBuilder {

        private volatile boolean isPresent = false;

        PresenceInboundBuilder(final boolean isPresent) {
            this.isPresent = isPresent;
        }

        void setPresent(final boolean present) {
            this.isPresent = present;
        }

        @Override
        public Inbound build() {
            return isPresent
                    ? super.build()
                    : NotPresentInbound.NOT_PRESENT_INBOUND;
        }
    }

    /**
     * Fake container that returns false on equals.
     */
    private static final class NotPresentInbound implements Inbound {

        private static final NotPresentInbound NOT_PRESENT_INBOUND = new NotPresentInbound();

        @Override
        public <E extends Augmentation<Inbound>> E getAugmentation(final Class<E> augmentationType) {
            throw new UnsupportedOperationException();
        }

        @Override
        public Class<? extends DataContainer> getImplementedInterface() {
            return Inbound.class;
        }

        @Override
        public boolean equals(final Object obj) {
            // This is necessary to fake this.equals(something)
            return obj == NOT_PRESENT_INBOUND;
        }
    }
}