/*
 * Copyright (c) 2017 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.hc2vpp.dhcp.write;

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

import io.fd.hc2vpp.common.translate.util.ByteDataTranslator;
import io.fd.hc2vpp.common.translate.util.FutureJVppCustomizer;
import io.fd.hc2vpp.common.translate.util.Ipv4Translator;
import io.fd.hc2vpp.common.translate.util.Ipv6Translator;
import io.fd.hc2vpp.common.translate.util.JvppReplyConsumer;
import io.fd.honeycomb.translate.spi.write.ListWriterCustomizer;
import io.fd.honeycomb.translate.write.WriteContext;
import io.fd.honeycomb.translate.write.WriteFailedException;
import io.fd.vpp.jvpp.core.dto.DhcpProxyConfig;
import io.fd.vpp.jvpp.core.future.FutureJVppCore;
import java.util.List;
import javax.annotation.Nonnull;
import org.opendaylight.yang.gen.v1.http.fd.io.hc2vpp.yang.dhcp.rev180629.dhcp.attributes.relays.Relay;
import org.opendaylight.yang.gen.v1.http.fd.io.hc2vpp.yang.dhcp.rev180629.dhcp.attributes.relays.RelayKey;
import org.opendaylight.yang.gen.v1.http.fd.io.hc2vpp.yang.dhcp.rev180629.relay.attributes.Server;
import org.opendaylight.yang.gen.v1.http.fd.io.hc2vpp.yang.vpp.fib.table.management.rev180521.Ipv6;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.IpAddressNoZone;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

final class DhcpRelayCustomizer extends FutureJVppCustomizer implements ListWriterCustomizer<Relay, RelayKey>,
    JvppReplyConsumer, ByteDataTranslator, Ipv6Translator, Ipv4Translator {
    private static final Logger LOG = LoggerFactory.getLogger(DhcpRelayCustomizer.class);

    DhcpRelayCustomizer(final FutureJVppCore vppApi) {
        super(vppApi);
    }

    @Override
    public void writeCurrentAttributes(@Nonnull final InstanceIdentifier<Relay> id, @Nonnull final Relay dataAfter,
                                       @Nonnull final WriteContext writeContext) throws WriteFailedException {
        LOG.debug("Writing Relay {} dataAfter={}", id, dataAfter);
        checkArgument(dataAfter.getServer() != null && !dataAfter.getServer().isEmpty(), "At least one DHCP server needs to be configured");
        for (final Server server : dataAfter.getServer()) {
            setRelay(id, dataAfter, server, true);
        }
    }

    @Override
    public void updateCurrentAttributes(@Nonnull final InstanceIdentifier<Relay> id, @Nonnull final Relay dataBefore,
                                        @Nonnull final Relay dataAfter, @Nonnull final WriteContext writeContext)
        throws WriteFailedException {
        LOG.debug("Updating Relay {} before={} after={}", id, dataBefore, dataAfter);
        final List<Server> serversBefore = dataBefore.getServer();
        checkArgument(serversBefore != null && !serversBefore.isEmpty(),
            "At least one DHCP server needs to be configured before update operation");
        final List<Server> serversAfter = dataAfter.getServer();
        checkArgument(serversAfter != null && !serversAfter.isEmpty(),
            "At least one DHCP server needs to be configured after update operation");

        // remove old servers (we do not expect many, so no need for efficient search):
        for (final Server server : serversBefore) {
            if (!serversAfter.contains(server)) {
                setRelay(id, dataAfter, server, false);
            }
        }
        // and add new ones:
        for (final Server server : serversAfter) {
            if (!serversBefore.contains(server)) {
                setRelay(id, dataAfter, server, true);
            }
        }
    }

    @Override
    public void deleteCurrentAttributes(@Nonnull final InstanceIdentifier<Relay> id, @Nonnull final Relay dataBefore,
                                        @Nonnull final WriteContext writeContext) throws WriteFailedException {
        LOG.debug("Removing Relay {} dataBefore={}", id, dataBefore);
        checkArgument(dataBefore.getServer() != null && !dataBefore.getServer().isEmpty(),
            "At least one DHCP server needs to be configured");
        for (final Server server : dataBefore.getServer()) {
            setRelay(id, dataBefore, server, false);
        }
    }

    private void setRelay(final InstanceIdentifier<Relay> id, final Relay relay, final Server server,
                          final boolean isAdd)
        throws WriteFailedException {
        final DhcpProxyConfig request = new DhcpProxyConfig();
        request.rxVrfId = relay.getRxVrfId().getValue().byteValue();
        final boolean isIpv6 = Ipv6.class == relay.getAddressFamily();
        request.isIpv6 = booleanToByte(isIpv6);
        request.serverVrfId = server.getVrfId().intValue();
        request.isAdd = booleanToByte(isAdd);
        request.dhcpServer = parseAddress(server.getAddress(), isIpv6);
        request.dhcpSrcAddress = parseAddress(relay.getGatewayAddress(), isIpv6);
        LOG.debug("DHCP config change id={} request={}", id, request);
        getReplyForWrite(getFutureJVpp().dhcpProxyConfig(request).toCompletableFuture(), id);
    }

    private byte[] parseAddress(@Nonnull final IpAddressNoZone address, final boolean isIpv6) {
        if (isIpv6) {
            return ipv6AddressNoZoneToArray(address.getIpv6AddressNoZone());
        } else {
            return ipv4AddressNoZoneToArray(address.getIpv4AddressNoZone());
        }
    }
}