package com.atlassian.sal.api.features;
   
   import com.google.common.base.Predicate;
   import com.google.common.collect.ImmutableMap;
   import com.google.common.collect.ImmutableSet;
   import com.google.common.collect.Iterables;
   import com.google.common.collect.Maps;
   
   import javax.annotation.concurrent.Immutable;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  
  /**
   * Represents a set of enabled features.
   *
   * @since 2.10
   */
  @Immutable
  public final class EnabledDarkFeatures
  {
      /**
       * Shorthand in case there are no enabled dark features or they are disabled
       */
      public static final EnabledDarkFeatures NONE = new EnabledDarkFeatures(ImmutableMap.<FeatureKeyScope, ImmutableSet<String>>of());
  
      private final ImmutableMap<FeatureKeyScope, ImmutableSet<String>> enabledFeatures;
  
      /**
       * Create an instance of enabled features based on the given map.
       * @param enabledFeatures a map of enabled features
       */
      public EnabledDarkFeatures(final ImmutableMap<FeatureKeyScope, ImmutableSet<String>> enabledFeatures)
      {
          checkNotNull(enabledFeatures, "enabledFeatures");
          this.enabledFeatures = ImmutableMap.copyOf(enabledFeatures);
      }
  
      /**
       * Return all enabled feature keys.
       * @return all enabled feature keys
       */
      public ImmutableSet<String> getFeatureKeys()
      {
          return ImmutableSet.copyOf(Iterables.concat(enabledFeatures.values()));
      }
  
      /**
       * Returns all enabled feature keys matching the given criteria.
       * @param criteria the filter condition to be applied on the set of enabled features
       * @return the filtered set of enabled features
       */
      public ImmutableSet<String> getFeatureKeys(final Predicate<FeatureKeyScope> criteria)
      {
          checkNotNull(criteria, "criteria");
          return ImmutableSet.copyOf(Iterables.concat(Maps.filterKeys(enabledFeatures, criteria).values()));
      }
  
      /**
       * Check that the given feature is enabled
       * @param featureKey the feature key to be checked
       * @return <code>true</code> if the given feature key is enabled, <code>false</code> otherwise
       */
      public boolean isFeatureEnabled(final String featureKey)
      {
          checkNotNull(featureKey, "featureKey");
          return Iterables.contains(Iterables.concat(enabledFeatures.values()), featureKey);
      }
  
      @Override
      public String toString()
      {
          return "EnabledDarkFeatures{enabledFeatures=" + enabledFeatures + '}';
      }
  
  }