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.NormalizeException;
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.LDAPMapping;
import at.knowcenter.wag.egov.egiz.sig.LDAPAPI;
import at.knowcenter.wag.egov.egiz.sig.SignatureObject;
import at.knowcenter.wag.egov.egiz.tools.Normalizer;

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

	private final Logger log = Logger.getLogger(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;

	protected LDAPAPIImpl() {
	    try {
			SettingsReader settings = SettingsReader.getInstance();
			
			ldapClientFactory = LDAPClientFactory.getInstance(LDAP_FACTORY_IDENTIFIER);
			// configure normalization of issuer according to method
			// normalizeIssuer(String) of at.knowcenter.wag.egov.egiz.sig.SignatureObject
			ldapClientFactory.setWhiteSpaceRemoval(true);
			ldapClientFactory.setNormalizer(new Normalizer().getInstance());

			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);
					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);
				log.warn("There are no LDAP mappings (" + buffer.toString() + ") declared within config file.");
			}
			
		} catch (SettingsException e) {
			log.error(e);
		} catch (SettingNotFoundException e) {
			log.error(e);
		} catch (LDAPException e) {
			log.error(e);
		} catch (NormalizeException e) {
			log.error(e);
		};
	}
	
	public String getURL(String issuer) {
		String url = null;
		try {
			LDAPClient client = ldapClientFactory.createClient(issuer);
			url = client.getUrl().toString();
		} catch (LDAPException e) {
			log.error(e);
		}
		return url;
	}

	public byte[] loadBase64CertificateFromLDAP(String serialNumber, String issuer) {
		byte[] base64CertData = null;
		try {
			LDAPClient client = ldapClientFactory.createClient(issuer);
			X509Certificate x509certificate = client.retrieveCertificate(new BigInteger(serialNumber));
			base64CertData = Util.Base64Encode(x509certificate.toByteArray());
		} catch (LDAPException e) {
			log.error(e);
		}
		return base64CertData;
	}

}