/*
    * #%L
    * wcm.io
    * %%
    * Copyright (C) 2019 wcm.io
    * %%
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   * #L%
   */
  package io.wcm.caravan.jaxrs.publisher.impl;
  
  import static io.wcm.caravan.jaxrs.publisher.impl.ServletContainerBridge.isJaxRsGlobal;
  
  import javax.ws.rs.Path;
  import javax.ws.rs.container.PreMatching;
  import javax.ws.rs.ext.Provider;
  
  import org.osgi.framework.Bundle;
  import org.osgi.framework.BundleContext;
  import org.osgi.framework.ServiceReference;
  import org.osgi.util.tracker.ServiceTracker;
  
  import io.wcm.caravan.jaxrs.publisher.JaxRsComponent;
  
  /**
   * Tracks {@link JaxRsComponent} instances.
   */
  class JaxRsComponentTracker extends ServiceTracker<JaxRsComponent, Object> {
  
    private final ServletContainerBridge bridge;
    private final BundleContext bundleContext;
    private final Bundle bundle;
  
    JaxRsComponentTracker(ServletContainerBridge bridge) {
      super(bridge.getBundleContext(), JaxRsComponent.class, null);
      this.bridge = bridge;
      this.bundleContext = bridge.getBundleContext();
      this.bundle = bridge.getBundle();
    }
  
    @Override
    public Object addingService(ServiceReference<JaxRsComponent> reference) {
      if (isJaxRsGlobal(reference)) {
        JaxRsComponent serviceInstance = bundle.getBundleContext().getService(reference);
        if (isJaxRsComponent(serviceInstance)) {
          ServletContainerBridge.log.debug("Register global component {} for {}", serviceInstance.getClass().getName(), bundle.getSymbolicName());
          bridge.getGlobalComponents().add(serviceInstance);
          bridge.markAsDirty();
        }
      }
      else if (reference.getBundle() == bundle) {
        JaxRsComponent serviceInstance = bundle.getBundleContext().getService(reference);
        if (isJaxRsComponent(serviceInstance)) {
          ServletContainerBridge.log.debug("Register component {} for {}", serviceInstance.getClass().getName(), bundle.getSymbolicName());
          bridge.getLocalComponents().add(serviceInstance);
          bridge.markAsDirty();
        }
      }
      return super.addingService(reference);
    }
  
    @Override
    public void removedService(ServiceReference<JaxRsComponent> reference, Object service) {
      if (isJaxRsGlobal(reference)) {
        JaxRsComponent serviceInstance = bundle.getBundleContext().getService(reference);
        if (isJaxRsComponent(serviceInstance)) {
          ServletContainerBridge.log.debug("Unregister global component {} for {}", serviceInstance.getClass().getName(), bundle.getSymbolicName());
          bridge.getGlobalComponents().remove(serviceInstance);
          bundleContext.ungetService(reference);
          bridge.markAsDirty();
        }
      }
      else if (reference.getBundle() == bundle) {
        JaxRsComponent serviceInstance = bundle.getBundleContext().getService(reference);
        if (isJaxRsComponent(serviceInstance)) {
          ServletContainerBridge.log.debug("Unregister component {} for {}", serviceInstance.getClass().getName(), bundle.getSymbolicName());
          bridge.getLocalComponents().remove(serviceInstance);
          bundleContext.ungetService(reference);
          bridge.markAsDirty();
        }
      }
      super.removedService(reference, service);
    }
  
    private boolean isJaxRsComponent(Object serviceInstance) {
      return (serviceInstance instanceof JaxRsComponent && hasAnyJaxRsAnnotation(serviceInstance.getClass()));
    }
  
    private boolean hasAnyJaxRsAnnotation(Class<?> clazz) {
     return clazz.isAnnotationPresent(Path.class)
         || clazz.isAnnotationPresent(Provider.class)
         || clazz.isAnnotationPresent(PreMatching.class);
   }
 
 }