/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001-2004 Caucho Technology, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Caucho Technology (http://www.caucho.com/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "Burlap", "Resin", and "Caucho" must not be used to
 *    endorse or promote products derived from this software without prior
 *    written permission. For written permission, please contact
 *    info@caucho.com.
 *
 * 5. Products derived from this software may not be called "Resin"
 *    nor may "Resin" appear in their names without prior written
 *    permission of Caucho Technology.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL CAUCHO TECHNOLOGY OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @author Scott Ferguson
 */

package com.caucho.burlap.client;

import java.io.*;
import java.util.*;

import java.net.URL;
import java.net.HttpURLConnection;
import java.net.URLConnection;
import java.net.MalformedURLException;

import java.lang.reflect.Proxy;

import javax.naming.*;
import javax.naming.spi.*;

import com.caucho.burlap.io.BurlapRemoteResolver;
import com.caucho.burlap.io.BurlapInput;
import com.caucho.burlap.io.BurlapOutput;
import com.caucho.burlap.io.AbstractBurlapInput;
import com.caucho.burlap.io.AbstractBurlapOutput;
import com.caucho.burlap.io.BurlapRemoteObject;

import com.caucho.services.client.ServiceProxyFactory;

/**
 * Factory for creating Burlap client stubs.  The returned stub will
 * call the remote object for all methods.
 *
 * <pre>
 * String url = "http://localhost:8080/ejb/hello";
 * HelloHome hello = (HelloHome) factory.create(HelloHome.class, url);
 * </pre>
 *
 * After creation, the stub can be like a regular Java class.  Because
 * it makes remote calls, it can throw more exceptions than a Java class.
 * In particular, it may throw protocol exceptions.
 *
 * The factory can also be configured as a JNDI resource.  The factory
 * expects to parameters: "type" and "url", corresponding to the two
 * arguments to <code>create</code>
 *
 * In Resin 3.0, the above example would be configured as:
 * <pre>
 * &lt;reference>
 *   &lt;name>hessian/hello&lt;/name>
 *   &lt;factory>com.caucho.hessian.client.HessianProxyFactory&lt;/factory>
 *   &lt;init url="http://localhost:8080/ejb/hello"/>
 *         type="test.HelloHome"/>
 * &lt;/reference>
 * </pre>
 *
 * To get the above resource, use JNDI as follows:
 * <pre>
 * Context ic = new InitialContext();
 * HelloHome hello = (HelloHome) ic.lookup("java:comp/env/burlap/hello");
 *
 * System.out.println("Hello: " + hello.helloWorld());
 * </pre>
 *
 * <h3>Authentication</h3>
 *
 * <p>The proxy can use HTTP basic authentication if the user and the
 * password are set.
 */
public class BurlapProxyFactory implements ServiceProxyFactory, ObjectFactory {
  private BurlapRemoteResolver _resolver;
  
  private String _user;
  private String _password;
  private String _basicAuth;

  private boolean _isOverloadEnabled = false;

  /**
   * Creates the new proxy factory.
   */
  public BurlapProxyFactory()
  {
    _resolver = new BurlapProxyResolver(this);
  }

  /**
   * Sets the user.
   */
  public void setUser(String user)
  {
    _user = user;
    _basicAuth = null;
  }

  /**
   * Sets the password.
   */
  public void setPassword(String password)
  {
    _password = password;
    _basicAuth = null;
  }

  /**
   * Returns true if overloaded methods are allowed (using mangling)
   */
  public boolean isOverloadEnabled()
  {
    return _isOverloadEnabled;
  }

  /**
   * set true if overloaded methods are allowed (using mangling)
   */
  public void setOverloadEnabled(boolean isOverloadEnabled)
  {
    _isOverloadEnabled = isOverloadEnabled;
  }

  /**
   * Returns the remote resolver.
   */
  public BurlapRemoteResolver getRemoteResolver()
  {
    return _resolver;
  }

  /**
   * Creates the URL connection.
   */
  protected URLConnection openConnection(URL url)
    throws IOException
  {
    URLConnection conn = url.openConnection();

    conn.setDoOutput(true);

    if (_basicAuth != null)
      conn.setRequestProperty("Authorization", _basicAuth);
    else if (_user != null && _password != null) {
      _basicAuth = "Basic " + base64(_user + ":" + _password);
      conn.setRequestProperty("Authorization", _basicAuth);
    }

    return conn;
  }

  /**
   * Creates a new proxy with the specified URL.  The API class uses
   * the java.api.class value from _hessian_
   *
   * @param url the URL where the client object is located.
   *
   * @return a proxy to the object with the specified interface.
   */
  public Object create(String url)
    throws MalformedURLException, ClassNotFoundException
  {
    BurlapMetaInfoAPI metaInfo;

    metaInfo = (BurlapMetaInfoAPI) create(BurlapMetaInfoAPI.class, url);

    String apiClassName =
      (String) metaInfo._burlap_getAttribute("java.api.class");

    if (apiClassName == null)
      throw new BurlapRuntimeException(url + " has an unknown api.");

    ClassLoader loader = Thread.currentThread().getContextClassLoader();

    Class apiClass = Class.forName(apiClassName, false, loader);

    return create(apiClass, url);
  }

  /**
   * Creates a new proxy with the specified URL.  The returned object
   * is a proxy with the interface specified by api.
   *
   * <pre>
   * String url = "http://localhost:8080/ejb/hello");
   * HelloHome hello = (HelloHome) factory.create(HelloHome.class, url);
   * </pre>
   *
   * @param api the interface the proxy class needs to implement
   * @param url the URL where the client object is located.
   *
   * @return a proxy to the object with the specified interface.
   */
  public Object create(Class api, String urlName)
    throws MalformedURLException
  {
    URL url = new URL(urlName);

    try {
      // clear old keepalive connections
      HttpURLConnection conn = (HttpURLConnection) url.openConnection();

      conn.setRequestProperty("Connection", "close");

      InputStream is = conn.getInputStream();

      is.close();

      conn.disconnect();
    } catch (IOException e) {
    }
    
    BurlapProxy handler = new BurlapProxy(this, url);

    return Proxy.newProxyInstance(api.getClassLoader(),
                                  new Class[] { api,
                                                BurlapRemoteObject.class },
                                  handler);
  }

  public AbstractBurlapInput getBurlapInput(InputStream is)
  {
    AbstractBurlapInput in = new BurlapInput(is);
    in.setRemoteResolver(getRemoteResolver());

    return in;
  }

  public BurlapOutput getBurlapOutput(OutputStream os)
  {
    BurlapOutput out = new BurlapOutput(os);

    return out;
  }

  /**
   * JNDI object factory so the proxy can be used as a resource.
   */
  public Object getObjectInstance(Object obj, Name name,
                                  Context nameCtx,
				  Hashtable<?,?> environment)
    throws Exception
  {
    Reference ref = (Reference) obj;

    String api = null;
    String url = null;
    String user = null;
    String password = null;

    for (int i = 0; i < ref.size(); i++) {
      RefAddr addr = ref.get(i);

      String type = addr.getType();
      String value = (String) addr.getContent();

      if (type.equals("type"))
        api = value;
      else if (type.equals("url"))
        url = value;
      else if (type.equals("user"))
        setUser(value);
      else if (type.equals("password"))
        setPassword(value);
    }

    if (url == null)
      throw new NamingException("`url' must be configured for BurlapProxyFactory.");
    // XXX: could use meta protocol to grab this
    if (api == null)
      throw new NamingException("`type' must be configured for BurlapProxyFactory.");

    ClassLoader loader = Thread.currentThread().getContextClassLoader();
    Class apiClass = Class.forName(api, false, loader);

    return create(apiClass, url);
  }

  /**
   * Creates the Base64 value.
   */
  private String base64(String value)
  {
    StringBuffer cb = new StringBuffer();

    int i = 0;
    for (i = 0; i + 2 < value.length(); i += 3) {
      long chunk = (int) value.charAt(i);
      chunk = (chunk << 8) + (int) value.charAt(i + 1);
      chunk = (chunk << 8) + (int) value.charAt(i + 2);
        
      cb.append(encode(chunk >> 18));
      cb.append(encode(chunk >> 12));
      cb.append(encode(chunk >> 6));
      cb.append(encode(chunk));
    }
    
    if (i + 1 < value.length()) {
      long chunk = (int) value.charAt(i);
      chunk = (chunk << 8) + (int) value.charAt(i + 1);
      chunk <<= 8;

      cb.append(encode(chunk >> 18));
      cb.append(encode(chunk >> 12));
      cb.append(encode(chunk >> 6));
      cb.append('=');
    }
    else if (i < value.length()) {
      long chunk = (int) value.charAt(i);
      chunk <<= 16;

      cb.append(encode(chunk >> 18));
      cb.append(encode(chunk >> 12));
      cb.append('=');
      cb.append('=');
    }

    return cb.toString();
  }

  public static char encode(long d)
  {
    d &= 0x3f;
    if (d < 26)
      return (char) (d + 'A');
    else if (d < 52)
      return (char) (d + 'a' - 26);
    else if (d < 62)
      return (char) (d + '0' - 52);
    else if (d == 62)
      return '+';
    else
      return '/';
  }
}

