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.ArrayList;
import java.util.Collections;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.lang.ArrayUtils;
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 ldapClients;

	protected LDAPClientFactoryImpl() {
		this.ldapClients = new Hashtable();
	}
	
	public static String rfc2253Name2Domain(Name name) {
		Object[] values = name.getRDNValues(ObjectID.domainComponent);
		if (values == null) {
			return null;
		}
		StringBuffer buffer = new StringBuffer();
		for (int i = 0; i < values.length; i++) {
			buffer.append(values[i]);
			if (i+1 < values.length) {
				buffer.append(".");
			}
		}
		return buffer.toString();
	}
	
	public static String rfc2253Name2Domain(String nameString) throws RFC2253NameParserException {
		RFC2253NameParser nameParser = new RFC2253NameParser(nameString);
		return rfc2253Name2Domain(nameParser.parse());
	}

	private List instantiateLDAPClients(String issuerName) throws LDAPException {
		if (!super.hasBeenConfigured()) {
			log.warn(super.getClass().getName() + " has not been configured yet.");
		}
		List ldapClients = new ArrayList();
		List mappings = super.getMappings(issuerName);
		if (mappings == null || mappings.isEmpty()) {
			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 + "\"...");
				LDAPClient client = new LDAPClientImpl(alternativeURLString);
				ldapClients.add(client);
			} catch (RFC2253NameParserException e) {
				throw new LDAPException(e);
			}
		} else {
			log.debug("Instantiating LDAP clients for " + ArrayUtils.toString(mappings.toArray()) + ".");
			Iterator mappingIt = mappings.iterator();
			while (mappingIt.hasNext()) {
			   LDAPMapping mapping = (LDAPMapping) mappingIt.next();
			   ldapClients.add(new LDAPClientImpl(mapping));
			}
		}
		return ldapClients;
	}
	
	public synchronized List createClients(String issuerName) throws LDAPException {
		if (issuerName == null) {
			throw new NullPointerException("Issuer name must not be null.");
		}
		if (issuerName.length() == 0) {
			throw new IllegalArgumentException("Issuer name must not be empty.");
		}
		List ldapClientList = (List) ldapClients.get(issuerName);
		if (ldapClientList == null) {
		   ldapClientList = instantiateLDAPClients(issuerName);
			ldapClients.put(issuerName, ldapClientList);
		}
		return Collections.unmodifiableList(ldapClientList);
	}

}