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

	public String getURL(String issuer) {
		this.initializeFactoryImpl();
		String url = null;
		try {
			LDAPClient client = this.ldapClientFactory.createClient(issuer);
			url = client.getUrl().toString();
		} catch (LDAPException e) {
			this.log.error(e);
		}
		return url;
	}

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

}