/*

 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.dns.client.internal;

import jdk.dns.client.AddressFamily;

import jdk.dns.client.ex.DnsInvalidAttributeIdentifierException;

public class ResourceClassType {

    int rrclass;

    int rrtype;

    ResourceClassType(int rrtype) {

        this.rrclass = ResourceRecord.CLASS_INTERNET;

        this.rrtype = rrtype;

    }

    public int getRecordClass() {

        return rrclass;

    }

    public int getRecordType() {

        return rrtype;

    }

    public static ResourceClassType fromAddressFamily(AddressFamily addressFamily) {

        ResourceClassType[] cts;

        try {

            cts = ResourceClassType.attrIdsToClassesAndTypes(typeFromAddressFamily(addressFamily));

        } catch (DnsInvalidAttributeIdentifierException e) {

            return new ResourceClassType(ResourceRecord.QTYPE_STAR);

        }

        return ResourceClassType.getClassAndTypeToQuery(cts);

    }

    private static String[] typeFromAddressFamily(AddressFamily addressFamily) {

        switch (addressFamily) {

            case IPv4:

                return new String[]{"A", "CNAME"};

            case IPv6:

                return new String[]{"AAAA", "CNAME"};

            default:

                return new String[]{"A", "AAAA", "CNAME"};

        }

    }

    public static ResourceClassType[] attrIdsToClassesAndTypes(String[] attrIds)

            throws DnsInvalidAttributeIdentifierException {

        if (attrIds == null) {

            return null;

        }

        ResourceClassType[] cts = new ResourceClassType[attrIds.length];

        for (int i = 0; i < attrIds.length; i++) {

            cts[i] = fromAttrId(attrIds[i]);

        }

        return cts;

    }

    private static ResourceClassType fromAttrId(String attrId)

            throws DnsInvalidAttributeIdentifierException {

        if (attrId.isEmpty()) {

            throw new DnsInvalidAttributeIdentifierException(

                    "Attribute ID cannot be empty");

        }

        int rrclass;

        int rrtype;

        int space = attrId.indexOf(' ');

        // class

        if (space < 0) {

            rrclass = ResourceRecord.CLASS_INTERNET;

        } else {

            String className = attrId.substring(0, space);

            rrclass = ResourceRecord.getRrclass(className);

            if (rrclass < 0) {

                throw new DnsInvalidAttributeIdentifierException(

                        "Unknown resource record class '" + className + '\'');

            }

        }

        // type

        String typeName = attrId.substring(space + 1);

        rrtype = ResourceRecord.getType(typeName);

        if (rrtype < 0) {

            throw new DnsInvalidAttributeIdentifierException(

                    "Unknown resource record type '" + typeName + '\'');

        }

        return new ResourceClassType(rrtype);

    }

    /*

     * Returns the most restrictive resource record class and type

     * that may be used to query for records matching cts.

     * See classAndTypeMatch() for matching rules.

     */

    public static ResourceClassType getClassAndTypeToQuery(ResourceClassType[] cts) {

        int rrclass;

        int rrtype;

        if (cts == null) {

            // Query all records.

            throw new RuntimeException("Internal DNS resolver error");

        } else if (cts.length == 0) {

            // No records are requested, but we need to ask for something.

            rrtype = ResourceRecord.QTYPE_STAR;

        } else {

            rrclass = ResourceRecord.CLASS_INTERNET;

            rrtype = cts[0].rrtype;

            for (int i = 1; i < cts.length; i++) {

                if (rrclass != cts[i].rrclass) {

                    throw new RuntimeException("Internal error: Only CLASS_INTERNET is supported");

                }

                if (rrtype != cts[i].rrtype) {

                    rrtype = ResourceRecord.QTYPE_STAR;

                }

            }

        }

        return new ResourceClassType(rrtype);

    }

}