package org.apache.archiva.repository.metadata;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF 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.
   */
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.archiva.model.ArchivaModelCloner;
  import org.apache.archiva.model.ArchivaRepositoryMetadata;
  import org.apache.archiva.model.Plugin;
  import org.apache.archiva.model.SnapshotVersion;
  
  /**
   * RepositoryMetadataMerge 
   *
   *
   */
  public class RepositoryMetadataMerge
  {
      public static ArchivaRepositoryMetadata merge( final ArchivaRepositoryMetadata mainMetadata,
                                                     final ArchivaRepositoryMetadata sourceMetadata )
          throws RepositoryMetadataException
      {
          if ( mainMetadata == null )
          {
              throw new RepositoryMetadataException( "Cannot merge a null main project." );
          }
  
          if ( sourceMetadata == null )
          {
              throw new RepositoryMetadataException( "Cannot copy to a null parent project." );
          }
  
          ArchivaRepositoryMetadata merged = new ArchivaRepositoryMetadata();
  
          merged.setGroupId( merge( mainMetadata.getGroupId(), sourceMetadata.getGroupId() ) );
          merged.setArtifactId(  merge(mainMetadata.getArtifactId(), sourceMetadata.getArtifactId()));
          merged.setVersion( merge(mainMetadata.getVersion(), sourceMetadata.getVersion()) );
          merged.setReleasedVersion( merge( mainMetadata.getReleasedVersion(), sourceMetadata.getReleasedVersion() ) );
          merged.setSnapshotVersion( merge( mainMetadata.getSnapshotVersion(), sourceMetadata.getSnapshotVersion() ) );
          merged.setAvailableVersions( mergeAvailableVersions( mainMetadata.getAvailableVersions(), sourceMetadata.getAvailableVersions() ) );
          merged.setPlugins( mergePlugins( mainMetadata.getPlugins(), sourceMetadata.getPlugins() ) );
          
          //Don't set if merge was not possible
          long lastUpdated = mergeTimestamp( mainMetadata.getLastUpdated(), sourceMetadata.getLastUpdated());
          if (lastUpdated > -1)
          {
              merged.setLastUpdated(  Long.toString(lastUpdated) );
          }
          
          return merged;
      }
  
      private static boolean empty( String val )
      {
          if ( val == null )
          {
              return true;
          }
  
          return ( val.trim().length() <= 0 );
      }
      
      private static long mergeTimestamp(String mainTimestamp, String sourceTimestamp)
      {
          if (sourceTimestamp == null && mainTimestamp != null)
          {
              return convertTimestampToLong(mainTimestamp);
          }
          
          if (mainTimestamp == null && sourceTimestamp != null)
          {
              return convertTimestampToLong(sourceTimestamp);
          }
          
          if (sourceTimestamp == null && mainTimestamp == null)
          {
              return -1;
          }
          
          return mergeTimestamp(convertTimestampToLong(mainTimestamp), convertTimestampToLong(sourceTimestamp));
     }
     
     private static long mergeTimestamp(long mainTimestamp, long sourceTimestamp)
     { 
         return Math.max( mainTimestamp, sourceTimestamp );
     }
 
     private static SnapshotVersion merge( SnapshotVersion mainSnapshotVersion, SnapshotVersion sourceSnapshotVersion )
     {
         if ( sourceSnapshotVersion == null )
         {
             return mainSnapshotVersion;
         }
 
         if ( mainSnapshotVersion == null )
         {
             return ArchivaModelCloner.clone( sourceSnapshotVersion );
         }
 
         SnapshotVersion merged = new SnapshotVersion();
        
         long mainSnapshotLastUpdated = convertTimestampToLong(mainSnapshotVersion.getTimestamp());
         long sourceSnapshotLastUpdated = convertTimestampToLong(sourceSnapshotVersion.getTimestamp());
                         
         long lastUpdated = mergeTimestamp(mainSnapshotLastUpdated, sourceSnapshotLastUpdated);
         
         if (lastUpdated == mainSnapshotLastUpdated)
         {
             merged.setTimestamp(mainSnapshotVersion.getTimestamp());
             merged.setBuildNumber(mainSnapshotVersion.getBuildNumber());
         }
         else
         {
             merged.setTimestamp(sourceSnapshotVersion.getTimestamp());
             merged.setBuildNumber(sourceSnapshotVersion.getBuildNumber());
         }
 
         return merged;
     }
     
     private static long convertTimestampToLong(String timestamp)
     {
         if (timestamp == null)
         {
             return -1;
         }
         
         return getLongFromTimestampSafely(StringUtils.replace(timestamp, ".", ""));
     }
     
     private static long getLongFromTimestampSafely( String timestampString )
     {
         try
         {
             return Long.parseLong(timestampString);
         }
         catch (NumberFormatException e)
         {
             return -1;
         }
     }
 
     private static String merge( String main, String source )
     {
         if ( empty( main ) && !empty( source ) )
         {
             return source;
         }
 
         return main;
     }
     
     private static List<Plugin> mergePlugins(List<Plugin> mainPlugins, List<Plugin> sourcePlugins)
     {
         if ( sourcePlugins == null )
         {
             return mainPlugins;
         }
         
         if ( mainPlugins == null )
         {
             return clonePlugins( sourcePlugins );
         }
         
         List<Plugin> merged = clonePlugins( mainPlugins );
         
         for ( Plugin plugin : sourcePlugins )
         {
             if ( !merged.contains( plugin ) )
             {
                 merged.add( plugin );
             }
         }
 
         return merged;
     }
     
     /**
      * Clones a list of plugins.
      * 
      * This method exists because ArchivaModelCloner.clonePlugins() 
      * only works with artifact references.
      * 
      * @param plugins
      * @return list of cloned plugins
      */
     private static List<Plugin> clonePlugins(List<Plugin> plugins)
     {
         if (plugins == null)
         {
             return null;
         }
         
         List<Plugin> result = new ArrayList<>();
         
         for (Plugin plugin : plugins)
         {
             Plugin clonedPlugin = new Plugin();
             clonedPlugin.setArtifactId(plugin.getArtifactId());
             clonedPlugin.setName(plugin.getName());
             clonedPlugin.setPrefix(plugin.getPrefix());
             result.add(plugin);
         }
         
         return result;
     }
 
     private static List<String> mergeAvailableVersions( List<String> mainAvailableVersions, List<String> sourceAvailableVersions )
     {
         if ( sourceAvailableVersions == null )
         {
             return mainAvailableVersions;
         }
 
         if ( mainAvailableVersions == null )
         {
             return ArchivaModelCloner.cloneAvailableVersions( sourceAvailableVersions );
         }
 
         List<String> merged = ArchivaModelCloner.cloneAvailableVersions( mainAvailableVersions );
 
         for ( String sourceVersion : sourceAvailableVersions )
         {
             if ( !merged.contains( sourceVersion ) )
             {
                 merged.add( sourceVersion );
             }
         }
 
         return merged;
     }
 }