package at.knowcenter.wag.egov.egiz.ldap.client;

import iaik.asn1.ObjectID;
import iaik.asn1.structures.Name;
import iaik.utils.RFC2253NameParser;
import iaik.utils.RFC2253NameParserException;

import java.util.Hashtable;

import org.apache.log4j.Logger;

/**
 * @author <a href="mailto:thomas.knall@iaik.tugraz.at">Thomas Knall</a>
 */
public final class LDAPClientFactoryImpl extends LDAPClientFactory {

	private final Logger log = Logger.getLogger(getClass());
	
	private Hashtable<String, LDAPClient> ldapClients;

	protected LDAPClientFactoryImpl() {
		this.ldapClients = new Hashtable<String, LDAPClient>();
	}
	
	public static String rfc2253Name2Domain(String nameString) throws RFC2253NameParserException {
		RFC2253NameParser nameParser = new RFC2253NameParser(nameString);
		return rfc2253Name2Domain(nameParser.parse());
	}

	public static String rfc2253Name2Domain(Name name) {
		Object[] values = name.getRDNValues(ObjectID.domainComponent);
		if (values == null) {
			return null;
		}
		StringBuffer buffer = new StringBuffer();
		for (int i = values.length - 1; i >= 0; i--) {
			buffer.append(values[i]);
			if (i > 0) {
				buffer.append(".");
			}
		}
		return buffer.toString();
	}

	private LDAPClient instantiateLDAPClient(String issuerName) throws LDAPException {
		if (!super.hasBeenConfigured()) {
			log.warn(super.getClass().getSimpleName() + " has not been configured yet.");
		}
		LDAPClient client = null;
		LDAPMapping mapping = super.getMapping(issuerName);
		if (mapping == null) {
			try {
				String alternativeURLString = rfc2253Name2Domain(issuerName);
				if (alternativeURLString == null || alternativeURLString.length() == 0) {
					throw new LDAPException("Neither issuer name \"" + issuerName + "\" has been registered nor domain components were provided.");
				}
				alternativeURLString = "ldap://" + alternativeURLString;
				log.warn("Issuer name \"" + issuerName + "\" has not been registered; trying to instantiate client for url \"" + alternativeURLString + "\"...");
				client = new LDAPClientImpl(alternativeURLString);
			} catch (RFC2253NameParserException e) {
				throw new LDAPException(e);
			}
		} else {
			log.debug("Instantiating LDAP client for " + mapping + ".");
			client = new LDAPClientImpl(mapping);
		}
		return client;
	}
	
	public synchronized LDAPClient createClient(String issuerName) throws LDAPException {
		if (issuerName == null || issuerName.length() == 0) {
			throw new NullPointerException("Issuer name must not be null or empty.");
		}
		if (super.getNormalizer() != null) {
			issuerName = super.getNormalizer().normalize(issuerName);
		}
		LDAPClient ldapClient = ldapClients.get(issuerName);
		if (ldapClient == null) {
			ldapClient = instantiateLDAPClient(issuerName);
			ldapClients.put(issuerName, ldapClient);
		}
		return ldapClient;
	}

}