/*
 * Copyright (c) 2016 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.lispflowmapping.mapcache;

import org.opendaylight.lispflowmapping.interfaces.dao.ILispDAO;
import org.opendaylight.lispflowmapping.interfaces.dao.MappingEntry;
import org.opendaylight.lispflowmapping.interfaces.dao.SubKeys;
import org.opendaylight.lispflowmapping.interfaces.mapcache.IAuthKeyDb;
import org.opendaylight.lispflowmapping.lisp.util.MaskUtil;
import org.opendaylight.lispflowmapping.mapcache.lisp.LispMapCacheStringifier;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.lisp.address.types.rev151105.lisp.address.address.SourceDestKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.lfm.lisp.proto.rev151105.eid.container.Eid;
import org.opendaylight.yang.gen.v1.urn.opendaylight.lfm.lisp.proto.rev151105.mapping.authkey.container.MappingAuthkey;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Simple in-memory database for authentication keys, that works with 'simple' addresses (see lisp-proto.yang). It can
 * do longest prefix matching for IP addresses.
 *
 * @author Lorand Jakab
 *
 */
public class AuthKeyDb implements IAuthKeyDb {
    private static final Logger LOG = LoggerFactory.getLogger(AuthKeyDb.class);
    private ILispDAO dao;

    public AuthKeyDb(ILispDAO dao) {
        this.dao = dao;
    }

    private ILispDAO getVniTable(Eid eid) {
        long vni = 0;
        if (eid.getVirtualNetworkId() == null) {
            vni = 0;
        } else {
            vni = eid.getVirtualNetworkId().getValue();
        }
        return (ILispDAO) dao.getSpecific(vni, SubKeys.VNI);
    }

    private ILispDAO getOrInstantiateVniTable(Eid eid) {
        long vni = 0;
        if (eid.getVirtualNetworkId() == null) {
            vni = 0;
        } else {
            vni = eid.getVirtualNetworkId().getValue();
        }
        ILispDAO table = (ILispDAO) dao.getSpecific(vni, SubKeys.VNI);
        if (table == null) {
            table = dao.putNestedTable(vni, SubKeys.VNI);
        }
        return table;
    }

    @Override
    public void addAuthenticationKey(Eid eid, MappingAuthkey authKey) {
        Eid key = MaskUtil.normalize(eid);
        ILispDAO table = getOrInstantiateVniTable(key);
        table.put(key, new MappingEntry<>(SubKeys.AUTH_KEY, authKey));
    }

    private MappingAuthkey getAuthKeyLpm(Eid prefix, ILispDAO db) {
        short maskLength = MaskUtil.getMaskForAddress(prefix.getAddress());
        while (maskLength >= 0) {
            Eid key = MaskUtil.normalize(prefix, maskLength);
            Object password = db.getSpecific(key, SubKeys.AUTH_KEY);
            if (password != null && password instanceof MappingAuthkey) {
                return (MappingAuthkey) password;
            }
            maskLength -= 1;
        }
        return null;
    }

    /*
     * Retrieves authentication key from the database. As opposed to the mapping cache, Source/Dest keys are treated as
     * exact match keys here, and a two level longest prefix match is NOT performed.
     */
    @Override
    public MappingAuthkey getAuthenticationKey(Eid eid) {
        ILispDAO table = getVniTable(eid);
        if (table == null) {
            return null;
        }
        if (MaskUtil.isMaskable(eid.getAddress()) && !(eid.getAddress() instanceof SourceDestKey)) {
            return getAuthKeyLpm(eid, table);
        } else {
            Eid key = MaskUtil.normalize(eid);
            Object password = table.getSpecific(key, SubKeys.AUTH_KEY);
            if (password != null && password instanceof MappingAuthkey) {
                return (MappingAuthkey) password;
            } else {
                LOG.warn("Failed to find password!");
                return null;
            }
        }
    }

    @Override
    public void removeAuthenticationKey(Eid eid) {
        Eid key = MaskUtil.normalize(eid);
        ILispDAO table = getVniTable(key);
        if (table == null) {
            return;
        }
        table.removeSpecific(key, SubKeys.AUTH_KEY);
    }

    @Override
    public String printKeys() {
        return LispMapCacheStringifier.printKeys(dao);
    }
}