/*

 * Copyright (c) 2018, 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 com.sun.jndi.ldap;

import com.sun.jndi.ldap.spi.LdapDnsProvider;

import com.sun.jndi.ldap.spi.LdapDnsProviderResult;

import javax.naming.NamingException;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import java.util.Optional;

public class DefaultLdapDnsProvider {

    public Optional<LdapDnsProviderResult> lookupEndpoints(String url,

                                                           Map<?,?> env)

            throws NamingException

    {

        if (url == null || env == null) {

            throw new NullPointerException();

        }

        String domainName;

        List<String> endpoints = new ArrayList<>();

        LdapURL ldapUrl = new LdapURL(url);

        String dn = ldapUrl.getDN();

        String host = ldapUrl.getHost();

        int port = ldapUrl.getPort();

        String[] hostports;

        // handle a URL with no hostport (ldap:/// or ldaps:///)

        // locate the LDAP service using the URL's distinguished name

        if (host == null

                && port == -1

                && dn != null

                && (domainName = ServiceLocator.mapDnToDomainName(dn)) != null

                && (hostports = ServiceLocator.getLdapService(domainName, env)) != null) {

            // Generate new URLs that include the discovered hostports.

            // Reuse the original URL scheme.

            String scheme = ldapUrl.getScheme() + "://";

            String query = ldapUrl.getQuery();

            String urlSuffix = ldapUrl.getPath() + (query != null ? query : "");

            for (String hostPort : hostports) {

                // the hostports come from the DNS SRV records

                // we assume the SRV record is scheme aware

                endpoints.add(scheme + hostPort + urlSuffix);

            }

        } else {

            // we don't have enough information to set the domain name

            // correctly

            domainName = "";

            endpoints.add(url);

        }

        LdapDnsProviderResult res = new LdapDnsProviderResult(domainName, endpoints);

        if (res.getEndpoints().isEmpty() && res.getDomainName().isEmpty()) {

            return Optional.empty();

        } else {

            return Optional.of(res);

        }

    }

}