/*
 * 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.translate.v3po.interfaces.acl;

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

import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import io.fd.honeycomb.translate.v3po.util.TranslateUtils;
import io.fd.honeycomb.translate.v3po.util.WriteTimeoutException;
import io.fd.honeycomb.translate.write.WriteContext;
import io.fd.honeycomb.translate.write.WriteFailedException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CompletionStage;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import javax.annotation.Nonnull;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.access.control.list.rev160708.AclBase;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.access.control.list.rev160708.access.lists.AclKey;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.access.control.list.rev160708.access.lists.acl.AccessListEntries;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.access.control.list.rev160708.access.lists.acl.access.list.entries.Ace;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.access.control.list.rev160708.access.lists.acl.access.list.entries.ace.matches.AceType;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.access.control.list.rev160708.access.lists.acl.access.list.entries.ace.matches.ace.type.AceEth;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.access.control.list.rev160708.access.lists.acl.access.list.entries.ace.matches.ace.type.AceIp;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.access.control.list.rev160708.access.lists.acl.access.list.entries.ace.matches.ace.type.ace.ip.AceIpVersion;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.access.control.list.rev160708.access.lists.acl.access.list.entries.ace.matches.ace.type.ace.ip.ace.ip.version.AceIpv4;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.v3po.rev150105.ietf.acl.base.attributes.access.lists.Acl;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.openvpp.jvpp.VppBaseCallException;
import org.openvpp.jvpp.core.dto.ClassifyAddDelTable;
import org.openvpp.jvpp.core.dto.ClassifyAddDelTableReply;
import org.openvpp.jvpp.core.dto.ClassifyTableByInterface;
import org.openvpp.jvpp.core.dto.ClassifyTableByInterfaceReply;
import org.openvpp.jvpp.core.dto.InputAclSetInterface;
import org.openvpp.jvpp.core.dto.InputAclSetInterfaceReply;
import org.openvpp.jvpp.core.future.FutureJVppCore;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public final class IetfAClWriter {

    private static final Logger LOG = LoggerFactory.getLogger(IetfAClWriter.class);
    private final FutureJVppCore jvpp;

    private Map<AclType, AceWriter> aceWriters = new HashMap<>();

    public IetfAClWriter(@Nonnull final FutureJVppCore futureJVppCore) {
        this.jvpp = Preconditions.checkNotNull(futureJVppCore, "futureJVppCore should not be null");
        aceWriters.put(AclType.ETH, new AceEthWriter(futureJVppCore));
        aceWriters.put(AclType.IP4, new AceIp4Writer(futureJVppCore));
        aceWriters.put(AclType.IP6, new AceIp6Writer(futureJVppCore));
    }

    private static Stream<Ace> aclToAceStream(@Nonnull final Acl assignedAcl,
                                              @Nonnull final WriteContext writeContext) {
        final String aclName = assignedAcl.getName();
        final Class<? extends AclBase> aclType = assignedAcl.getType();

        // ietf-acl updates are handled first, so we use writeContext.readAfter
        final Optional<org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.access.control.list.rev160708.access.lists.Acl>
            aclOptional = writeContext.readAfter(AclWriter.ACL_ID.child(
            org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.access.control.list.rev160708.access.lists.Acl.class,
            new AclKey(aclName, aclType)));
        checkArgument(aclOptional.isPresent(), "Acl lists not configured");
        final org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.access.control.list.rev160708.access.lists.Acl
            acl = aclOptional.get();

        final AccessListEntries accessListEntries = acl.getAccessListEntries();
        checkArgument(accessListEntries != null, "access list entries not configured");

        return accessListEntries.getAce().stream();
    }

    void deleteAcl(@Nonnull final InstanceIdentifier<?> id, final int swIfIndex)
        throws WriteTimeoutException, WriteFailedException.DeleteFailedException {
        final ClassifyTableByInterface request = new ClassifyTableByInterface();
        request.swIfIndex = swIfIndex;

        try {
            final CompletionStage<ClassifyTableByInterfaceReply> cs = jvpp.classifyTableByInterface(request);
            final ClassifyTableByInterfaceReply reply = TranslateUtils.getReplyForWrite(cs.toCompletableFuture(), id);

            // We remove all ACL-related classify tables for given interface (we assume we are the only classify table
            // manager)
            removeClassifyTable(id, reply.l2TableId);
            removeClassifyTable(id, reply.ip4TableId);
            removeClassifyTable(id, reply.ip6TableId);
        } catch (VppBaseCallException e) {
            throw new WriteFailedException.DeleteFailedException(id, e);
        }
    }

    private void removeClassifyTable(@Nonnull final InstanceIdentifier<?> id, final int tableIndex)
        throws VppBaseCallException, WriteTimeoutException {

        if (tableIndex == -1) {
            return; // classify table id is absent
        }
        final ClassifyAddDelTable request = new ClassifyAddDelTable();
        request.tableIndex = tableIndex;
        final CompletionStage<ClassifyAddDelTableReply> cs = jvpp.classifyAddDelTable(request);
        TranslateUtils.getReplyForWrite(cs.toCompletableFuture(), id);
    }

    void write(@Nonnull final InstanceIdentifier<?> id, final int swIfIndex, @Nonnull final List<Acl> acls,
               @Nonnull final WriteContext writeContext)
        throws VppBaseCallException, WriteTimeoutException {

        // filter ACE entries and group by AceType
        final Map<AclType, List<Ace>> acesByType = acls.stream()
            .flatMap(acl -> aclToAceStream(acl, writeContext))
            // TODO we should not tolerate nulls, but throw some meaningful exceptions instead
            .filter(ace -> ace != null && ace.getMatches() != null && ace.getMatches().getAceType() != null &&
                ace.getActions() != null && ace.getActions().getPacketHandling() != null)
            .collect(Collectors.groupingBy(AclType::fromAce));

        final InputAclSetInterface request = new InputAclSetInterface();
        request.isAdd = 1;
        request.swIfIndex = swIfIndex;
        request.l2TableIndex = -1;
        request.ip4TableIndex = -1;
        request.ip6TableIndex = -1;

        // for each AceType:
        for (Map.Entry<AclType, List<Ace>> entry : acesByType.entrySet()) {
            final AclType aceType = entry.getKey();
            final List<Ace> aces = entry.getValue();
            LOG.trace("Processing ACEs of {} type: {}", aceType, aces);

            final AceWriter aceWriter = aceWriters.get(aceType);
            if (aceWriter == null) {
                LOG.warn("AceProcessor for {} not registered. Skipping ACE.", aceType);
            } else {
                aceWriter.write(id, aces, request);
            }
        }

        final CompletionStage<InputAclSetInterfaceReply> inputAclSetInterfaceReplyCompletionStage =
            jvpp.inputAclSetInterface(request);
        TranslateUtils.getReplyForWrite(inputAclSetInterfaceReplyCompletionStage.toCompletableFuture(), id);

    }

    private enum AclType {
        ETH, IP4, IP6;

        @Nonnull
        private static AclType fromAce(final Ace ace) {
            AclType result = null;
            final AceType aceType = ace.getMatches().getAceType();
            if (aceType instanceof AceEth) {
                result = ETH;
            } else if (aceType instanceof AceIp) {
                final AceIpVersion aceIpVersion = ((AceIp) aceType).getAceIpVersion();
                if (aceIpVersion instanceof AceIpv4) {
                    result = IP4;
                } else {
                    result = IP6;
                }
            }
            if (result == null) {
                throw new IllegalArgumentException(String.format("Not supported ace type %s", aceType));
            }
            return result;
        }
    }
}