/**
 * Licensed to jclouds, Inc. (jclouds) under one or more
 * contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  jclouds licenses this file
 * to you 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.
 */
package org.jclouds.blobstore.strategy.internal;

import static com.google.common.base.Preconditions.checkState;
import static org.jclouds.concurrent.FutureIterables.transformParallel;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;

import javax.annotation.Resource;
import org.jclouds.javax.annotation.concurrent.NotThreadSafe;
import javax.inject.Named;

import org.jclouds.Constants;
import org.jclouds.blobstore.AsyncBlobStore;
import org.jclouds.blobstore.domain.BlobMetadata;
import org.jclouds.blobstore.domain.PageSet;
import org.jclouds.blobstore.domain.StorageMetadata;
import org.jclouds.blobstore.domain.StorageType;
import org.jclouds.blobstore.domain.internal.PageSetImpl;
import org.jclouds.blobstore.reference.BlobStoreConstants;
import org.jclouds.http.handlers.BackoffLimitedRetryHandler;
import org.jclouds.logging.Logger;

import com.google.common.base.Function;
import com.google.common.base.Predicate;
import com.google.common.collect.Iterables;
import com.google.inject.Inject;

/**
 * Retrieves all blobmetadata in the list as efficiently as possible
 * 
 * @author Adrian Cole
 */
@NotThreadSafe
public class FetchBlobMetadata implements Function<PageSet<? extends StorageMetadata>, PageSet<? extends StorageMetadata>> {

   protected final BackoffLimitedRetryHandler retryHandler;
   protected final AsyncBlobStore ablobstore;
   protected final ExecutorService userExecutor;
   @Resource
   @Named(BlobStoreConstants.BLOBSTORE_LOGGER)
   protected Logger logger = Logger.NULL;

   private String container;
   /**
    * maximum duration of an blob Request
    */
   @Inject(optional = true)
   @Named(Constants.PROPERTY_REQUEST_TIMEOUT)
   protected Long maxTime;

   @Inject
   FetchBlobMetadata(@Named(Constants.PROPERTY_USER_THREADS) ExecutorService userExecutor, AsyncBlobStore ablobstore,
            BackoffLimitedRetryHandler retryHandler) {
      this.userExecutor = userExecutor;
      this.ablobstore = ablobstore;
      this.retryHandler = retryHandler;
   }

   public FetchBlobMetadata setContainerName(String container) {
      this.container = container;
      return this;
   }

   public PageSet<? extends StorageMetadata> apply(PageSet<? extends StorageMetadata> in) {
      checkState(container != null, "container name should be initialized");

      Iterable<BlobMetadata> returnv = transformParallel(Iterables.filter(in, new Predicate<StorageMetadata>() {

         @Override
         public boolean apply(StorageMetadata input) {
            return input.getType() == StorageType.BLOB;
         }

      }), new Function<StorageMetadata, Future<BlobMetadata>>() {

         @Override
         public Future<BlobMetadata> apply(StorageMetadata from) {
            return ablobstore.blobMetadata(container, from.getName());
         }

      }, userExecutor, maxTime, logger, String.format("getting metadata from containerName: %s", container));

      return new PageSetImpl<BlobMetadata>(returnv, in.getNextMarker());
   }
}