/**
    *
    * Copyright (C) 2011 Cloud Conscious, LLC. <info@cloudconscious.com>
    *
    * ====================================================================
    * 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.
   * ====================================================================
   */
  package org.jclouds.blobstore.internal;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  import static org.jclouds.blobstore.options.ListContainerOptions.Builder.recursive;
  
  import java.util.Set;
  import java.util.concurrent.Callable;
  import java.util.concurrent.ExecutorService;
  
  import javax.inject.Inject;
  import javax.inject.Named;
  
  import org.jclouds.Constants;
  import org.jclouds.blobstore.AsyncBlobStore;
  import org.jclouds.blobstore.BlobStoreContext;
  import org.jclouds.blobstore.ContainerNotFoundException;
  import org.jclouds.blobstore.domain.Blob;
  import org.jclouds.blobstore.domain.BlobBuilder;
  import org.jclouds.blobstore.domain.PageSet;
  import org.jclouds.blobstore.domain.StorageMetadata;
  import org.jclouds.blobstore.options.ListContainerOptions;
  import org.jclouds.blobstore.util.BlobUtils;
  import org.jclouds.blobstore.util.internal.BlobUtilsImpl;
  import org.jclouds.collect.Memoized;
  import org.jclouds.domain.Location;
  import org.jclouds.util.Assertions;
  
  import com.google.common.base.Supplier;
  import com.google.common.util.concurrent.Futures;
  import com.google.common.util.concurrent.ListenableFuture;
  
  /**
   * 
   * @author Adrian Cole
   */
  public abstract class BaseAsyncBlobStore implements AsyncBlobStore {
  
     protected final BlobStoreContext context;
     protected final BlobUtils blobUtils;
     protected final ExecutorService service;
     protected final Supplier<Location> defaultLocation;
     protected final Supplier<Set<? extends Location>> locations;
  
     @Inject
     protected BaseAsyncBlobStore(BlobStoreContext context, BlobUtils blobUtils,
              @Named(Constants.PROPERTY_USER_THREADS) ExecutorService service, Supplier<Location> defaultLocation,
              @Memoized Supplier<Set<? extends Location>> locations) {
        this.context = checkNotNull(context, "context");
        this.blobUtils = checkNotNull(blobUtils, "blobUtils");
        this.service = checkNotNull(service, "service");
        this.defaultLocation = checkNotNull(defaultLocation, "defaultLocation");
        this.locations = checkNotNull(locations, "locations");
     }
  
     @Override
     public BlobStoreContext getContext() {
        return context;
     }
  
     /**
      * invokes {@link BlobUtilsImpl#newBlob }
      */
     @Override
     public Blob newBlob(String name) {
        return blobUtils.newBlob(name);
     }
  
     /**
      * invokes {@link BlobUtilsImpl#blobBuilder }
      */
     @Override
     public BlobBuilder blobBuilder(String name) {
        return blobUtils.blobBuilder().name(name);
     }
  
     /**
      * This implementation invokes
      * {@link #list(String,org.jclouds.blobstore.options.ListContainerOptions)}
      * 
      * @param container
      *           container name
     */
    @Override
    public ListenableFuture<PageSet<? extends StorageMetadata>> list(String container) {
       return this.list(container, org.jclouds.blobstore.options.ListContainerOptions.NONE);
    }
 
    /**
     * This implementation invokes {@link #countBlobs} with the
     * {@link ListContainerOptions#recursive} option.
     * 
     * @param container
     *           container name
     */
    @Override
    public ListenableFuture<Long> countBlobs(String container) {
       return countBlobs(container, recursive());
    }
 
    /**
     * This implementation invokes {@link BlobUtilsImpl#countBlobs}
     * 
     * @param container
     *           container name
     */
    @Override
    public ListenableFuture<Long> countBlobs(final String containerName, final ListContainerOptions options) {
       return org.jclouds.concurrent.Futures.makeListenable(service.submit(new Callable<Long>() {
          public Long call() throws Exception {
             return blobUtils.countBlobs(containerName, options);
          }
 
          @Override
          public String toString() {
             return "countBlobs(" + containerName + ")";
          }
       }), service);
    }
 
    /**
     * This implementation invokes {@link #clearContainer} with the
     * {@link ListContainerOptions#recursive} option.
     * 
     * @param container
     *           container name
     */
    @Override
    public ListenableFuture<Void> clearContainer(final String container) {
       return clearContainer(container, recursive());
    }
 
    /**
     * This implementation invokes {@link BlobUtilsImpl#clearContainer}
     * 
     * @param container
     *           container name
     */
    @Override
    public ListenableFuture<Void> clearContainer(final String containerName, final ListContainerOptions options) {
       return org.jclouds.concurrent.Futures.makeListenable(service.submit(new Callable<Void>() {
 
          public Void call() throws Exception {
             blobUtils.clearContainer(containerName, options);
             return null;
          }
 
          @Override
          public String toString() {
             return "clearContainer(" + containerName + ")";
          }
       }), service);
    }
 
    /**
     * This implementation invokes {@link BlobUtilsImpl#deleteDirectory}.
     * 
     * @param container
     *           container name
     */
    @Override
    public ListenableFuture<Void> deleteDirectory(final String containerName, final String directory) {
       return org.jclouds.concurrent.Futures.makeListenable(service.submit(new Callable<Void>() {
 
          public Void call() throws Exception {
             blobUtils.deleteDirectory(containerName, directory);
             return null;
          }
 
          @Override
          public String toString() {
             return "deleteDirectory(" + containerName + "," + directory + ")";
          }
       }), service);
    }
 
    /**
     * This implementation invokes {@link BlobUtilsImpl#directoryExists}
     * 
     * @param container
     *           container name
     * @param directory
     *           virtual path
     */
    public ListenableFuture<Boolean> directoryExists(final String containerName, final String directory) {
       return org.jclouds.concurrent.Futures.makeListenable(service.submit(new Callable<Boolean>() {
 
          public Boolean call() throws Exception {
             return blobUtils.directoryExists(containerName, directory);
          }
 
          @Override
          public String toString() {
             return "directoryExists(" + containerName + "," + directory + ")";
          }
       }), service);
    }
 
    /**
     * This implementation invokes {@link BlobUtilsImpl#createDirectory}
     * 
     * @param container
     *           container name
     * @param directory
     *           virtual path
     */
 
    public ListenableFuture<Void> createDirectory(final String containerName, final String directory) {
 
       return blobUtils.directoryExists(containerName, directory) ? Futures.immediateFuture((Void) null)
                : org.jclouds.concurrent.Futures.makeListenable(service.submit(new Callable<Void>() {
                   public Void call() throws Exception {
                      blobUtils.createDirectory(containerName, directory);
                      return null;
                   }
 
                   @Override
                   public String toString() {
                      return "createDirectory(" + containerName + "," + directory + ")";
                   }
                }), service);
    }
 
    /**
     * This implementation invokes
     * {@link #getBlob(String,String,org.jclouds.blobstore.options.GetOptions)}
     * 
     * @param container
     *           container name
     * @param key
     *           blob key
     */
    @Override
    public ListenableFuture<Blob> getBlob(String container, String key) {
       return getBlob(container, key, org.jclouds.blobstore.options.GetOptions.NONE);
    }
 
    /**
     * This implementation invokes {@link #deleteAndEnsurePathGone}
     * 
     * @param container
     *           bucket name
     */
    @Override
    public ListenableFuture<Void> deleteContainer(final String container) {
       return org.jclouds.concurrent.Futures.makeListenable(service.submit(new Callable<Void>() {
 
          public Void call() throws Exception {
             deleteAndEnsurePathGone(container);
             return null;
          }
 
          @Override
          public String toString() {
             return "deleteContainer(" + container + ")";
          }
       }), service);
    }
 
    protected void deleteAndEnsurePathGone(final String container) {
       try {
          if (!Assertions.eventuallyTrue(new Supplier<Boolean>() {
             public Boolean get() {
                try {
                   clearContainer(container, recursive());
                   return deleteAndVerifyContainerGone(container);
                } catch (ContainerNotFoundException e) {
                   return true;
                }
             }
 
          }, 30000)) {
             throw new IllegalStateException(container + " still exists after deleting!");
          }
       } catch (InterruptedException e) {
          new IllegalStateException(container + " interrupted during deletion!", e);
       }
    }
 
    @Override
    public ListenableFuture<Set<? extends Location>> listAssignableLocations() {
       return Futures.<Set<? extends Location>> immediateFuture(locations.get());
    }
 
    protected abstract boolean deleteAndVerifyContainerGone(String container);
 
 }