package com.atlassian.sal.core.features;
   
   import com.atlassian.fugue.Option;
   import com.atlassian.sal.api.features.DarkFeatureManager;
   import com.atlassian.sal.api.features.EnabledDarkFeatures;
   import com.atlassian.sal.api.user.UserManager;
   import com.google.common.collect.ImmutableSet;
   
   import java.util.Collections;
  import java.util.Set;
  
  /**
   * Default implementation of DarkFeatureManager - sufficient for any product which does not already have its own dark
   * feature framework. Does not implement per-user or per-site enabling.
   */
  public class DefaultDarkFeatureManager implements DarkFeatureManager
  {
      private final EnabledDarkFeatures enabledDarkFeatures;
      private final UserManager userManager;
  
      public DefaultDarkFeatureManager(UserManager userManager)
      {
          this.userManager = userManager;
          this.enabledDarkFeatures = createEnabledDarkFeatures();
      }
  
      private static EnabledDarkFeatures createEnabledDarkFeatures()
      {
          // initialize dark features based on system properties and contents of a properties file.
          final SystemDarkFeatureInitializer.SystemDarkFeatures systemDarkFeatures = SystemDarkFeatureInitializer.getSystemStartupDarkFeatures();
  
          final Set<String> systemEnabledFeatures = systemDarkFeatures.isDisableAll() ? Collections.<String>emptySet() : ImmutableSet.copyOf(systemDarkFeatures.getEnabled());
          return new EnabledDarkFeatures(systemEnabledFeatures, Collections.<String>emptySet(), Collections.<String>emptySet());
      }
  
      @Override
      public boolean isSystemFeatureEnabled(String featureKey)
      {
          return enabledDarkFeatures.getAllEnabledFeatures().contains(featureKey);
      }
  
      @Override
      public boolean isFeatureEnabled(String featureKey)
      {
          return isSystemFeatureEnabled(featureKey);
      }
  
      @Override
      public Option<Boolean> isFeatureEnabledForUser(String username, String featureKey)
      {
          return isUserExisting(username) ? Option.some(isSystemFeatureEnabled(featureKey)) : Option.<Boolean>none();
      }
  
      @Override
      public boolean hasSiteEditPermission()
      {
          // no modification supported at all
          return false;
      }
  
      @Override
      public void enableFeatureSiteWide(String featureKey)
      {
          // not supported
      }
  
      @Override
      public void disableFeatureSideWide(String featureKey)
      {
          // not supported
      }
  
      @Override
      public void enableFeatureForCurrentUser(String featureKey)
      {
          // not supported
      }
  
      @Override
      public void enableFeatureForUser(String username, String featureKey)
      {
          // not supported
      }
  
      @Override
      public void disableFeatureForCurrentUser(String featureKey)
      {
          // not supported
      }
  
      @Override
      public void disableFeatureForUser(String username, String featureKey)
      {
          // not supported
      }
  
      @Override
      public EnabledDarkFeatures getAllEnabledFeaturesForCurrentUser()
      {
         return enabledDarkFeatures;
     }
 
     @Override
     public Option<EnabledDarkFeatures> getAllEnabledFeaturesForUser(String username)
     {
         return isUserExisting(username) ? Option.some(getAllEnabledFeaturesForCurrentUser()) : Option.<EnabledDarkFeatures>none();
     }
 
     private boolean isUserExisting(String username)
     {
         return userManager.resolve(username) != null;
     }
 }