/*
 * Copyright (c) 2003, KNOPFLERFISH project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - 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.
 *
 * - Neither the name of the KNOPFLERFISH project nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS 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 THE
 * COPYRIGHT OWNER OR 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.
 */

package org.knopflerfish.bundle.http;

import java.util.Dictionary;
import java.util.Enumeration;
import java.util.Vector;

import javax.servlet.Servlet;
import javax.servlet.ServletException;

import org.osgi.framework.Bundle;
import org.osgi.service.http.HttpContext;
import org.osgi.service.http.NamespaceException;
import org.osgi.service.http.HttpService;

import org.knopflerfish.service.log.LogRef;


public class HttpServiceImpl implements HttpService {

  // public constants

  public final static String[] HTTP_INTERFACES = new String[] {
    HttpService.class.getName()
  };


  // private fields

  private final Bundle bundle;
  private final LogRef log;
  private final Registrations registrations;
  private final ServletContextManager contextManager;

  private final Vector bundleRegistrations = new Vector();

  private boolean closed = false;

  private HttpContext defaultBundleContext = null;


  // constructors

  public HttpServiceImpl(final Bundle bundle,
                         final LogRef log,
                         final Registrations registrations,
                         final ServletContextManager contextManager) {

    this.bundle = bundle;
    this.log = log;
    this.registrations = registrations;
    this.contextManager = contextManager;
  }


  // public methods

  public void register(String alias,
                       Registration registration) throws NamespaceException {

    int length = alias.length();

    if (length == 0 || alias.charAt(0) != '/')
      throw new IllegalArgumentException("The alias parameter must begin with slash: " + alias);

    if (length > 1 && alias.charAt(length - 1) == '/')
      throw new IllegalArgumentException("The alias parameter must not end with slash: " + alias);

    if (registrations.get(alias) != null)
      throw new NamespaceException("The alias is already in use: " + alias);

    bundleRegistrations.addElement(alias);
    registrations.put(alias, registration);

    if (log.doDebug())
      log.debug("Alias \"" +
                alias +
                "\" was registered by bundle " +
                bundle.getBundleId());
  }

  public void unregister(String alias, boolean destroy) {

    Registration registration = registrations.remove(alias);
    bundleRegistrations.removeElement(alias);

    if (destroy)
      registration.destroy();

    if (log.doDebug())
      log.debug("Alias \"" +
                alias +
                "\" was unregistered by bundle " +
                bundle.getBundleId());
  }

  public void unregisterBundle() {

    closed = true;

    while (!bundleRegistrations.isEmpty())
      unregister((String) bundleRegistrations.lastElement(), false);
  }


  // implements HttpService

  public void registerResources(String alias,
                                String realPath,
                                HttpContext httpContext)
      throws NamespaceException {

    if (closed)
      throw new IllegalStateException("Service has been unget");

    if (realPath.length() > 0 && realPath.charAt(realPath.length() - 1) == '/')
      throw new IllegalArgumentException("The name parameter must not end with slash: " + realPath);

    if (httpContext == null) {
      if (defaultBundleContext == null)
        defaultBundleContext = createDefaultHttpContext();
      httpContext = defaultBundleContext;
    }

    register(alias, new ResourceRegistration(alias,
                                             realPath,
                                             httpContext,
                                             contextManager));
  }

  public void registerServlet(String alias,
                              Servlet servlet,
                              Dictionary parameters,
                              HttpContext httpContext)
      throws NamespaceException, ServletException {

    if (closed)
      throw new IllegalStateException("Service has been unget");

    if (servlet == null)
      throw new IllegalArgumentException("Servlet parameter is null");

    if (httpContext == null) {
      if (defaultBundleContext == null)
        defaultBundleContext = createDefaultHttpContext();
      httpContext = defaultBundleContext;
    }

    Registration registration = null;
    try {
      registration = new ServletRegistration(alias,
                                             servlet,
                                             parameters,
                                             httpContext,
                                             contextManager,
                                             registrations);
      register(alias, registration);
    } catch (NamespaceException ne) {
      if (registration != null)
        registration.destroy();
      throw ne;
    } catch (ServletException se) {
      if (registration != null)
        registration.destroy();
      throw se;
    } catch (RuntimeException re) {
      if (registration != null)
        registration.destroy();
      throw re;
    }
  }

  public void unregister(String alias) {

    if (closed)
      throw new IllegalStateException("Service has been unget");

    if (registrations.get(alias) == null)
      throw new IllegalArgumentException("The alias was not registered: " + alias);

    if (!bundleRegistrations.contains(alias))
      throw new IllegalArgumentException("The alias was not registered by the calling bundle: " + alias);

    unregister(alias, true);
  }

  public HttpContext createDefaultHttpContext() {
    return new DefaultHttpContext(bundle);
  }

} // HttpServiceImpl