package com.atlassian.plugins.rest.common.multipart.jersey;
   
   import com.atlassian.plugins.rest.common.interceptor.impl.DispatchProviderHelper;
   import com.atlassian.plugins.rest.common.interceptor.impl.InterceptorChainBuilder;
   import com.atlassian.plugins.rest.common.multipart.FilePart;
   import com.atlassian.plugins.rest.common.multipart.MultipartForm;
   import com.atlassian.plugins.rest.common.multipart.MultipartFormParam;
   import com.sun.jersey.api.core.HttpContext;
   import com.sun.jersey.api.model.AbstractResourceMethod;
  import com.sun.jersey.api.model.Parameter;
  import com.sun.jersey.core.spi.component.ComponentScope;
  import com.sun.jersey.server.impl.inject.AbstractHttpContextInjectable;
  import com.sun.jersey.server.impl.inject.InjectableValuesProvider;
  import com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider;
  import com.sun.jersey.spi.dispatch.RequestDispatcher;
  import com.sun.jersey.spi.inject.Injectable;
  
  import java.lang.annotation.Annotation;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  import javax.ws.rs.core.Context;
  import javax.ws.rs.ext.Provider;
  
  /**
   * Dispatchs requests to methods with MultipartFormParam parameters
   *
   * @since 2.4
   */
  @Provider
  public class MultipartFormDispatchProvider extends AbstractResourceMethodDispatchProvider {
      private static final String MULTIPART_FORM_PROPERTY = "com.atlassian.rest.multipart.form";
  
      private
      @Context
      InterceptorChainBuilder interceptorChainBuilder;
  
      @Override
      public RequestDispatcher create(AbstractResourceMethod abstractResourceMethod) {
          DispatchProviderHelper helper = new DispatchProviderHelper(interceptorChainBuilder);
          return helper.create(abstractResourceMethod, getInjectableValuesProvider(abstractResourceMethod));
      }
  
      @Override
      protected InjectableValuesProvider getInjectableValuesProvider(final AbstractResourceMethod method) {
          // We only return one if we find a MultipartFormParam annotated parameter
          for (Parameter param : method.getParameters()) {
              for (Annotation annotation : param.getAnnotations()) {
                  if (annotation instanceof MultipartFormParam) {
                      // Here we return an object that will parse the form (done by MultipartFormMessageBodyReader when getEntity() is called)
                      return new InjectableValuesProvider(getInjectables(method)) {
                          @Override
                          public Object[] getInjectableValues(final HttpContext context) {
                              if (!context.getProperties().containsKey(MULTIPART_FORM_PROPERTY)) {
                                  context.getProperties().put(MULTIPART_FORM_PROPERTY, context.getRequest().getEntity(
                                          MultipartForm.class, MultipartForm.class, method.getAnnotations()));
                              }
                              return super.getInjectableValues(context);
                          }
                      };
                  }
              }
          }
          return null;
      }
  
      private List<Injectable> getInjectables(AbstractResourceMethod method) {
          List<Injectable> is = new ArrayList<Injectable>(method.getParameters().size());
          for (int i = 0; i < method.getParameters().size(); i++) {
              Parameter parameter = method.getParameters().get(i);
              Injectable<?> injectable = null;
              // We don't support entities
              if (Parameter.Source.ENTITY == parameter.getSource()) {
                  return null;
              }
              for (Annotation annotation : parameter.getAnnotations()) {
                  if (annotation instanceof MultipartFormParam) {
                      // It's a multipart parameter, we get the injectable for it
                      injectable = getMultipartFormInjectable(parameter, (MultipartFormParam) annotation);
                  }
              }
              if (injectable == null) {
                  // This defaults back so that everything else, eg @HeaderParam, @Context etc can get injected
                  injectable = getInjectableProviderContext().getInjectable(parameter, ComponentScope.PerRequest);
              }
              if (injectable == null) {
                  return null;
              }
              is.add(injectable);
          }
          return is;
      }
  
      private Injectable<?> getMultipartFormInjectable(final Parameter parameter, final MultipartFormParam annotation) {
          // FilePart
          if (parameter.getParameterClass().equals(FilePart.class)) {
              return new AbstractHttpContextInjectable<FilePart>() {
                 public FilePart getValue(final HttpContext context) {
                     return ((MultipartForm) context.getProperties().get(MULTIPART_FORM_PROPERTY)).getFilePart(annotation.value());
                 }
             };
         }
         // Collection of file parts
         if (Collection.class.isAssignableFrom(parameter.getParameterClass())) {
             return new AbstractHttpContextInjectable<Collection<FilePart>>() {
                 public Collection<FilePart> getValue(final HttpContext context) {
                     Collection<FilePart> parts = ((MultipartForm) context.getProperties().get(MULTIPART_FORM_PROPERTY)).getFileParts(annotation.value());
                     if (parameter.getParameterClass().isAssignableFrom(Collection.class)) {
                         return parts;
                     } else if (parameter.getParameterClass().isAssignableFrom(List.class)) {
                         return new ArrayList<FilePart>(parts);
                     } else if (parameter.getParameterClass().isAssignableFrom(Set.class)) {
                         return new HashSet<FilePart>(parts);
                     }
                     return null;
                 }
             };
         }
         return null;
     }
 }