package org.codehaus.mojo.clirr;
   
   /*
    * Copyright 2006 The Codehaus
    *
    * 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.
   */
  
  import net.sf.clirr.core.ApiDifference;
  import net.sf.clirr.core.DiffListener;
  import net.sf.clirr.core.Severity;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Delegates to a number of listeners, filtering by severity.
   *
   * @author <a href="mailto:brett@apache.org">Brett Porter</a>
   */
  public class DelegatingListener
      implements MojoDiffListener
  {
      private final List<DiffListener> listeners;
  
      private final Severity minSeverity;
  
      private final List<Difference> ignored;
  
      private Map<Difference, Map<Object, List<ApiDifference>>> deferredMatchesPerDifference = new HashMap<Difference, Map<Object, List<ApiDifference>>>();
  
      public DelegatingListener( List<DiffListener> listeners, Severity minSeverity, List<Difference> ignored )
      {
          this.listeners = listeners == null ? Collections.<DiffListener>emptyList() : listeners;
  
          this.minSeverity = minSeverity;
  
          this.ignored = ignored == null ? Collections.<Difference>emptyList() : ignored;
      }
  
      public void start()
      {
          deferredMatchesPerDifference.clear();
  
          for ( DiffListener listener : listeners )
          {
              listener.start();
          }
      }
  
      public void reportDiff( ApiDifference apiDifference )
      {
          if ( ( minSeverity == null || minSeverity.compareTo( apiDifference.getMaximumSeverity() ) <= 0 ) )
          {
              Difference reasonToIgnoreDiff = getReasonToIgnoreDiff( apiDifference );
              if ( reasonToIgnoreDiff == null )
              {
                  reportDiff_(apiDifference);
              }
              else
              {
                  reportIgnoredDiff(apiDifference, reasonToIgnoreDiff);
              }
          }
      }
  
      private void reportDiff_(ApiDifference apiDifference)
      {
          for ( DiffListener listener : listeners )
          {
              listener.reportDiff( apiDifference );
          }
      }
  
      public void reportIgnoredDiff( ApiDifference ignoredDiff, Difference reason )
      {
          for ( DiffListener listener : listeners )
          {
              if ( listener instanceof MojoDiffListener )
              {
                  MojoDiffListener l = (MojoDiffListener) listener;
                  l.reportIgnoredDiff( ignoredDiff, reason );
              }
          }
      }
  
     public void stop()
     {
         //process the deferred matches now
         for ( Map.Entry<Difference, Map<Object, List<ApiDifference>>> perDifferenceEntry : deferredMatchesPerDifference.entrySet() )
         {
             Difference diff = perDifferenceEntry.getKey();
             Map<Object, List<ApiDifference>> diffsPerId = perDifferenceEntry.getValue();
 
             for ( List<ApiDifference> apiDiffs : diffsPerId.values() )
             {
                 if ( !diff.resolveDefferedMatches( apiDiffs ) )
                 {
                     for ( ApiDifference apiDiff : apiDiffs )
                     {
                         reportDiff_(apiDiff);
                     }
                 }
                 else
                 {
                     for ( ApiDifference apiDiff : apiDiffs )
                     {
                         reportIgnoredDiff(apiDiff, diff);
                     }
                 }
             }
         }
 
         //and stop the underlying listeners
         for ( DiffListener listener : listeners )
         {
             listener.stop();
         }
     }
 
     private Difference getReasonToIgnoreDiff( ApiDifference apiDiff )
     {
         if ( ignored == null )
         {
             return null;
         }
 
         boolean someDeferred = false;
         boolean matched = false;
 
         Difference reason = null;
         for ( Difference difference : ignored )
         {
             if ( difference == null )
             {
                 continue;
             }
             Difference.Result res = difference.matches( apiDiff );
 
             switch ( res.getCode() )
             {
                 case Difference.Result.MATCHED:
                     if ( reason == null )
                     {
                         reason = difference;
                     }
                     matched = true;
                     break;
                 case Difference.Result.NOT_MATCHED:
                     break;
                 case Difference.Result.DEFERRED_MATCH:
                     Map<Object, List<ApiDifference>> diffsPerDifferentiator =
                         deferredMatchesPerDifference.get( difference );
                     if ( diffsPerDifferentiator == null )
                     {
                         diffsPerDifferentiator = new HashMap<Object, List<ApiDifference>>();
                         deferredMatchesPerDifference.put( difference, diffsPerDifferentiator );
                     }
 
                     List<ApiDifference> diffs = diffsPerDifferentiator.get( res.getDifferentiator() );
                     if ( diffs == null )
                     {
                         diffs = new ArrayList<ApiDifference>();
                         diffsPerDifferentiator.put( res.getDifferentiator(), diffs );
                     }
 
                     diffs.add( apiDiff );
                     if ( reason == null )
                     {
                         reason = difference;
                     }
                     someDeferred = true;
                     break;
             }
         }
 
         if ( matched || someDeferred )
         {
           return reason;
         }
         return null;
     }
 }