/**
 * <copyright> Copyright 2006 by Know-Center, Graz, Austria </copyright>
 * PDF-AS has been contracted by the E-Government Innovation Center EGIZ, a
 * joint initiative of the Federal Chancellery Austria and Graz University of
 * Technology.
 *
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * http://www.osor.eu/eupl/
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 */
package at.knowcenter.wag.egov.egiz.ldap.api;

import iaik.utils.Util;
import iaik.x509.X509Certificate;

import java.math.BigInteger;
import java.util.Iterator;
import java.util.List;

import org.apache.log4j.Logger;

import at.knowcenter.wag.egov.egiz.cfg.SettingsReader;
import at.knowcenter.wag.egov.egiz.exceptions.SettingNotFoundException;
import at.knowcenter.wag.egov.egiz.exceptions.SettingsException;
import at.knowcenter.wag.egov.egiz.ldap.client.LDAPClient;
import at.knowcenter.wag.egov.egiz.ldap.client.LDAPClientFactory;
import at.knowcenter.wag.egov.egiz.ldap.client.LDAPException;
import at.knowcenter.wag.egov.egiz.ldap.client.LDAPIssuerNameFilter;
import at.knowcenter.wag.egov.egiz.ldap.client.LDAPMapping;
import at.knowcenter.wag.egov.egiz.sig.LDAPAPI;

/**
 * @author <a href="mailto:thomas.knall@iaik.tugraz.at">Thomas Knall</a>
 */
public class LDAPAPIImpl implements LDAPAPI {

	private final Logger log = Logger.getLogger(this.getClass());

	/**
	 * Prefix for specific entry in config properties file.
	 */
	private static final String PROP_LDAP_PREFIX = "ldap_mapping";

	private static final String PROP_ISSUER_NAME_POSTFIX = "issuer_name";

	private static final String PROP_LDAP_URL_POSTFIX = "url";

	private static final String PROP_SERIAL_ATTR_POSTFIX = "serial_attr";

	private static final String LDAP_FACTORY_IDENTIFIER = "PDF-AS LDAP Support";

	private LDAPClientFactory ldapClientFactory;

	private LDAPIssuerNameFilter ldapIssuerNameFilter;

	protected LDAPAPIImpl() {
		this.ldapClientFactory = null;
		this.ldapIssuerNameFilter = null;
	}

	private void initializeFactoryImpl() {
		if (this.ldapClientFactory == null) {
			try {
				SettingsReader settings = SettingsReader.getInstance();

				this.ldapClientFactory = LDAPClientFactory.getInstance(LDAP_FACTORY_IDENTIFIER);
				this.ldapClientFactory.setLDAPIssuerNameFilter(this.ldapIssuerNameFilter);

				List mappingKeys = settings.getKeys(PROP_LDAP_PREFIX);
				if (mappingKeys != null) {
					Iterator it = mappingKeys.iterator();
					while (it.hasNext()) {
						String keyPrefix = PROP_LDAP_PREFIX + "." + (String) it.next() + ".";
						String issuerName = settings.getSetting(keyPrefix + PROP_ISSUER_NAME_POSTFIX);
						String ldapURL = settings.getSetting(keyPrefix + PROP_LDAP_URL_POSTFIX);
						String serialAttr = settings.getSetting(keyPrefix + PROP_SERIAL_ATTR_POSTFIX,
								null);

						LDAPMapping ldapMapping = new LDAPMapping(issuerName, ldapURL, serialAttr);
						this.ldapClientFactory.registerMapping(ldapMapping);
					}
				} else {
					StringBuffer buffer = new StringBuffer();
					buffer.append(PROP_LDAP_PREFIX).append(".foo.").append(PROP_ISSUER_NAME_POSTFIX)
							.append(", ");
					buffer.append(PROP_LDAP_PREFIX).append(".foo.").append(PROP_LDAP_URL_POSTFIX)
							.append(", ");
					buffer.append(PROP_LDAP_PREFIX).append(".foo.").append(PROP_SERIAL_ATTR_POSTFIX);
					this.log.warn("There are no LDAP mappings (" + buffer.toString()
							+ ") declared within config file.");
				}

			} catch (SettingsException e) {
				this.log.error(e.getMessage(), e);
			} catch (SettingNotFoundException e) {
				this.log.error(e.getMessage(), e);
			} catch (LDAPException e) {
				this.log.error(e.getMessage(), e);
			}
			;
		}
	}

	public byte[] loadBase64CertificateFromLDAP(String serialNumber, String issuer) {
		this.initializeFactoryImpl();
		byte[] base64CertData = null;
		try {
			List clients = this.ldapClientFactory.createClients(issuer);
			Iterator clientIt = clients.iterator();
         X509Certificate x509certificate = null;
			while (clientIt.hasNext() && x509certificate == null) {
			   LDAPClient client = (LDAPClient) clientIt.next();
			   try {
			      x509certificate = client.retrieveCertificate(new BigInteger(serialNumber));
			   } catch (LDAPException e) {
			      this.log.error(e.getMessage(), e);
			   }
			}
			if (x509certificate != null) {
				base64CertData = Util.Base64Encode(x509certificate.toByteArray());
			}
		} catch (LDAPException e) {
			this.log.error(e.getMessage(), e);
		}
		return base64CertData;
	}

	public void setIssuerNameFilter(LDAPIssuerNameFilter filter) throws LDAPAPIException {
		if (this.ldapClientFactory != null) {
			throw new LDAPAPIException("LDAPIssuerNameFilter must be applied before mappings are registered.");
		}
		this.ldapIssuerNameFilter = filter;
	}

}