package com.sun.jndi.ldap;

import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import javax.naming.NamingException;
import javax.naming.spi.ldap.LdapDnsProvider;
import javax.naming.spi.ldap.LdapDnsProviderResult;

public class DefaultLdapDnsProvider extends LdapDnsProvider {
    @Override
    public LdapDnsProviderResult lookupEndpoints(String url, Hashtable<?,?> env) {
        String domainName = "";
        List<String> urls = new ArrayList<>();
        try {
            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
                    urls.add(scheme + hostPort + urlSuffix);
                }
            } else {
                // we don't have enough information to set the domain name
                // correctly
                domainName = "";
                urls.add(url);
            }
        } catch (NamingException e) {
            // leave list of resolved urls empty
        }
        return new LdapDnsProviderResult(domainName, urls);
    }

}