/*
 * Copyright 2011 by Graz University of Technology, Austria
 * MOCCA has been developed 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.gv.egiz.bku.utils.urldereferencer;

import java.io.IOException;
import java.net.MalformedURLException;
import java.util.HashMap;
import java.util.Map;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.SSLSocketFactory;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Class used to dereference (external URLs).
 * 
 * @author wbauer
 * 
 */
public class URLDereferencerImpl implements URLDereferencer {

  private final Logger log = LoggerFactory.getLogger(URLDereferencerImpl.class);

  private static URLDereferencerImpl instance = new URLDereferencerImpl();

  private Map<String, URLProtocolHandler> handlerMap = new HashMap<String, URLProtocolHandler>();

  private HostnameVerifier hostnameVerifier;
  private SSLSocketFactory sslSocketFactory;
  
  private URLDereferencerImpl() {
    registerHandlers();
  }

  /**
   * 
   * @param aUrl
   *          must not be null
   * @throws MalformedURLException
   *           if the protocol is not supported
   * @throws IOException if the url cannot be dereferenced (e.g. formdata not provided)
   *           
   */
  @Override
  public StreamData dereference(String aUrl)
      throws IOException {
    log.debug("Looking for handler for URL: {}.", aUrl);
    int i = aUrl.indexOf(":");
    if (i == -1) {
      throw new MalformedURLException("Invalid url: " + aUrl);
    }
    String protocol = aUrl.substring(0, i).toLowerCase().trim();
    URLProtocolHandler handler = handlerMap.get(protocol);
    if (handler == null) {
      throw new MalformedURLException("No handler for protocol: " + protocol
          + " found");
    }
    handler.setHostnameVerifier(hostnameVerifier);
    handler.setSSLSocketFactory(sslSocketFactory);
    return handler.dereference(aUrl);
  }

  /**
   * Registers a handler for a protocol.
   * 
   * @param aProtocol
   * @param aHandler
   *          may be set to null to disable this protocol
   */
  public void registerHandler(String aProtocol, URLProtocolHandler aHandler) {
    handlerMap.put(aProtocol.toLowerCase(), aHandler);
  }

  public static URLDereferencerImpl getInstance() {
    return instance;
  }

  protected void registerHandlers() {
    URLProtocolHandler handler = new HTTPURLProtocolHandlerImpl();
    for (String proto : HTTPURLProtocolHandlerImpl.PROTOCOLS) {
      handlerMap.put(proto, handler);
    }
  }
  
  public void setHostnameVerifier(HostnameVerifier hostnameVerifier) {
    this.hostnameVerifier = hostnameVerifier;
  }

  public void setSSLSocketFactory(SSLSocketFactory socketFactory) {
    this.sslSocketFactory = socketFactory;
  }
}