/**
    * 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.location.config;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  import static com.google.inject.name.Names.named;
  import static org.jclouds.location.reference.LocationConstants.ISO3166_CODES;
  import static org.jclouds.location.reference.LocationConstants.PROPERTY_REGION;
  import static org.jclouds.location.reference.LocationConstants.PROPERTY_ZONE;
  
  import java.util.Map;
  import java.util.Set;
  
  import javax.inject.Inject;
  import javax.inject.Singleton;
  
  import org.jclouds.location.Iso3166;
  
  import com.google.common.base.Splitter;
  import com.google.common.collect.ImmutableMap;
  import com.google.common.collect.ImmutableSet;
  import com.google.common.collect.ImmutableMap.Builder;
  import com.google.inject.ConfigurationException;
  import com.google.inject.Injector;
  import com.google.inject.Key;
  
  /**
   * 
   * looks for properties bound to the naming conventions jclouds.region.{@code regionId}
   * .iso3166-codes and jclouds.zone.{@code zoneId}.iso3166-codes
   * 
   * @author Adrian Cole
   */
  @Singleton
  public class ProvideIso3166CodesByLocationIdViaProperties implements javax.inject.Provider<Map<String, Set<String>>> {
  
     private final Injector injector;
  
     @Inject
     ProvideIso3166CodesByLocationIdViaProperties(Injector injector) {
        this.injector = checkNotNull(injector, "injector");
     }
  
     @Singleton
     @Iso3166
     @Override
     public Map<String, Set<String>> get() {
        Builder<String, Set<String>> codes = ImmutableMap.<String, Set<String>> builder();
        for (String key : ImmutableSet.of(PROPERTY_REGION, PROPERTY_ZONE))
           try {
              String regionString = injector.getInstance(Key.get(String.class, named(key + "s")));
              for (String region : Splitter.on(',').split(regionString)) {
                 try {
                    codes.put(region, ImmutableSet.copyOf(Splitter.on(',')
                             .split(
                                      injector.getInstance(Key.get(String.class, named(key + "." + region + "."
                                               + ISO3166_CODES))))));
                 } catch (ConfigurationException e) {
                    // this happens if regions property isn't set
                    // services not run by AWS may not have regions, so this is ok.
                 }
              }
           } catch (ConfigurationException e) {
              // this happens if regions property isn't set
              // services not run by AWS may not have regions, so this is ok.
           }
        return codes.build();
     }
  }