/*
 * Copyright 2003 Federal Chancellery Austria
 * MOA-SPSS has been developed in a cooperation between BRZ, the Federal
 * Chancellery Austria - ICT staff unit, 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.egovernment.moa.spss.server.invoke;

import iaik.xml.crypto.utils.URI;
import iaik.xml.crypto.utils.URIException;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

import at.gv.egovernment.moa.spss.MOAApplicationException;
import at.gv.egovernment.moa.spss.server.transaction.TransactionContext;
import at.gv.egovernment.moa.spss.server.transaction.TransactionContextManager;
import at.gv.egovernment.moa.spss.util.ExternalURIVerifier;

/**
 * Resolve external URIs and provide them as a stream.
 * 
 * @author Patrick Peck
 * @version $Id$
 */
public class ExternalURIResolver {

  /** The MIME type of the content currently resolved. */
  private String contentType;

  /**
   * Return a stream to data at the given URI.
   * 
   * This method will try to open an <code>URLConnection</code> to the given
   * URI. Access to the file system is disallowed.
   * 
   * @param uriStr The URI to resolve.
   * @return InputStream The data contained at the URI.
   * @throws MOAApplicationException An error occurred resolving the URI (e.g.,
   * the URI is syntactically incorrect or the stream could not be opened).
   */
  public InputStream resolve(String uriStr) throws MOAApplicationException {
    URI uri;
    URL url;
    URLConnection connection;
    InputStream is;

    // build the URI
    try {
      uri = new URI(uriStr);
    } catch (URIException e) {
      throw new MOAApplicationException("2207", new Object[] { uriStr });
    }

    // disallow access to local file system
    if ("".equals(uri.getScheme()) || "file".equals(uri.getScheme())) {
      throw new MOAApplicationException("2213", new Object[] { uriStr });
    }

    // if we have local content (SOAP with attachments)
    if ("formdata".equals(uri.getScheme())) {
      TransactionContext context = TransactionContextManager.getInstance().getTransactionContext();
      if (context==null) {
        //no transaction
        throw new MOAApplicationException("2282", new Object[] { uri });
      } else {
        InputStream attachmentIs = context.getAttachmentInputStream(uri);
        if (attachmentIs != null) {
          setContentType(context.getAttachmentContentType(uri.getPath()));
          return attachmentIs;
        } else {
          //maybe attachments provided but no suiting attachment found
          throw new MOAApplicationException("2282", new Object[] { uri });
        }
      } 
    } 
    
    // convert URI to URL
    try {
      // create the URL
      url = new URL(uriStr);
      //System.out.println("ExternalURIResolver: " + url);
      ExternalURIVerifier.verify(url.getHost(), url.getPort());
      
    } catch (MalformedURLException e) {
      throw new MOAApplicationException("2214", new Object[] { uriStr });
    }

    // build the URLConnection
    try {
      connection = url.openConnection();
      if ("http".equals(url.getProtocol())) {
        HttpURLConnection httpConnection = (HttpURLConnection) connection;
        // disallow redirects
        httpConnection.setInstanceFollowRedirects(false);

        httpConnection.connect();
        if (httpConnection.getResponseCode() != HttpURLConnection.HTTP_OK) {
          throw new MOAApplicationException("2208", new Object[] { uri });
        }
      } else if ("https".equals(url.getProtocol())) {
        /* 
         * this doesn't work because of some interaction between the IAIK
         * JCE and Sun JSSE that results in an "Invalid AVA format" exception
         */

        /*
        HttpsURLConnection httpsConnection = (HttpsURLConnection) connection;
        InputStream trustStore =
          getClass().getResourceAsStream(DEFAULT_TRUST_STORE);
        SSLSocketFactory factory =
          SSLUtils.getSSLSocketFactory("jks", trustStore, "changeit");
        httpsConnection.setSSLSocketFactory(factory);
        httpsConnection.connect();
        if (httpConnection.getResponseCode() != HttpURLConnection.HTTP_OK) {
          throw new MOAApplicationException("2208", new Object[] { uri });
        }
        */
        connection.connect();
      } else {
        connection.connect();
      }
      is = connection.getInputStream();
    } catch (IOException e) {
      throw new MOAApplicationException("2208", new Object[] { uri }, e);
    } /*catch (GeneralSecurityException e) {
         throw new MOAApplicationException("2208", new Object[] { uri }, e);
       }*/

    // set the content type
    setContentType(connection.getContentType());

    return is;
  }

  /**
   * Set the content type of the data at the URI.
   * 
   * @param contentType The content type to set.
   */
  protected void setContentType(String contentType) {
    this.contentType = contentType;
  }

  /**
   * Return the content type of the data detected at the URI from the previous
   * call of <code>resolve()</code>.
   * 
   * @return String The content type.
   */
  public String getContentType() {
    return contentType;
  }

}