package com.atlassian.plugins.rest.common.security.jersey;
   
   import java.lang.annotation.Annotation;
   import java.util.List;
   
   import javax.ws.rs.HttpMethod;
   import javax.ws.rs.ext.Provider;
   
   import com.atlassian.plugin.PluginAccessor;
  import com.atlassian.plugin.event.PluginEventManager;
  import com.atlassian.plugin.tracker.DefaultPluginModuleTracker;
  import com.atlassian.plugin.tracker.PluginModuleTracker;
  import com.atlassian.plugins.rest.common.security.CorsAllowed;
  import com.atlassian.plugins.rest.common.security.descriptor.CorsDefaults;
  import com.atlassian.plugins.rest.common.security.descriptor.CorsDefaultsModuleDescriptor;
  
  import com.sun.jersey.api.model.AbstractMethod;
  import com.sun.jersey.spi.container.ResourceFilter;
  import com.sun.jersey.spi.container.ResourceFilterFactory;
  
  import org.springframework.beans.factory.DisposableBean;
  
  import static java.util.Collections.emptyList;
  import static java.util.Collections.singletonList;
  
  /**
   * Factory for the Cross-Origin Resource Sharing resource filter, triggering off {@link com.atlassian.plugins.rest.common.security.CorsAllowed}.
   *
   * @since 2.6
   */
  @Provider
  public class CorsResourceFilterFactory implements ResourceFilterFactory, DisposableBean {
      private final PluginModuleTracker<CorsDefaults, CorsDefaultsModuleDescriptor> tracker;
  
      public CorsResourceFilterFactory(PluginAccessor pluginAccessor, PluginEventManager pluginEventManager) {
          tracker = new DefaultPluginModuleTracker<CorsDefaults, CorsDefaultsModuleDescriptor>(pluginAccessor, pluginEventManager, CorsDefaultsModuleDescriptor.class);
      }
  
      public List<ResourceFilter> create(final AbstractMethod method) {
          if (annotationIsPresent(method, CorsAllowed.class)) {
              String targetMethod = HttpMethod.GET;
              for (Annotation ann : method.getAnnotations()) {
                  HttpMethod m = ann.annotationType().getAnnotation(HttpMethod.class);
                  if (m != null) {
                      targetMethod = m.value();
                      break;
                  }
              }
  
              ResourceFilter resourceFilter = new CorsResourceFilter(tracker, targetMethod);
              return singletonList(resourceFilter);
  
          } else {
              return emptyList();
          }
      }
  
      private static boolean annotationIsPresent(AbstractMethod method, Class<? extends Annotation> annotationType) {
          return method.isAnnotationPresent(annotationType)
                  || method.getResource().isAnnotationPresent(annotationType)
                  || packageHasAnnotation(annotationType, method.getResource().getResourceClass().getPackage());
      }
  
      private static boolean packageHasAnnotation(Class<? extends Annotation> annotationClass, Package resourcePackage) {
          return resourcePackage != null && resourcePackage.isAnnotationPresent(annotationClass);
      }
  
      public void destroy() {
          tracker.close();
      }
  }