/*******************************************************************************
 * Copyright (c) 2011, 2015 Frank Appel and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Frank Appel - initial API and implementation
 ******************************************************************************/
package org.eclipse.rap.rwt.osgi.internal;

import java.util.*;

import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;


class ServiceContainer<S> {

  private final Set<ServiceHolder<S>> services;
  private final BundleContext bundleContext;

  ServiceContainer( BundleContext bundleContext ) {
    this.bundleContext = bundleContext;
    this.services = new HashSet<>();
  }

  ServiceHolder<S> add( S service ) {
    return add( service, null );
  }

  ServiceHolder<S> add( ServiceReference<S> reference ) {
    return add( bundleContext.getService( reference ), reference );
  }

  void remove( S service ) {
    services.remove( find( service ) );
  }

  ServiceHolder<S>[] getServices() {
    Set<ServiceHolder<S>> result = new HashSet<>();
    Iterator<ServiceHolder<S>> iterator = services.iterator();
    while( iterator.hasNext() ) {
      result.add( iterator.next() );
    }
    return result.toArray( new ServiceHolder[ result.size() ]);
  }

  ServiceHolder<S> find( S service ) {
    ServiceHolder<S> result = null;
    for( ServiceHolder<S> serviceHolder : services ) {
      S found = serviceHolder.getService();
      if( service.equals( found ) ) {
        result = serviceHolder;
      }
    }
    return result;
  }

  void clear() {
    services.clear();
  }

  int size() {
    return services.size();
  }

  private ServiceHolder<S> add( S service, ServiceReference<S> reference ) {
    ServiceHolder<S> result = find( service );
    if( result == null ) {
      result = new ServiceHolder<>( service, reference );
      services.add( result );
    } else if( reference != null && result.serviceReference == null ) {
      result.setServiceReference( reference );
    }
    return result;
  }

  static class ServiceHolder<S> {

    private ServiceReference<S> serviceReference;
    private final S service;

    private ServiceHolder( S service, ServiceReference<S> serviceReference ) {
      this.service = service;
      this.serviceReference = serviceReference;
    }

    S getService() {
      return service;
    }

    ServiceReference<S> getReference() {
      return serviceReference;
    }

    private void setServiceReference( ServiceReference<S> serviceReference ) {
      this.serviceReference = serviceReference;
    }
  }

}