package org.apache.maven.resolver.examples.util;
   
   /*
    * 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.io.PrintStream;
  import java.text.DecimalFormat;
  import java.text.DecimalFormatSymbols;
  import java.util.Locale;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  import org.eclipse.aether.transfer.AbstractTransferListener;
  import org.eclipse.aether.transfer.MetadataNotFoundException;
  import org.eclipse.aether.transfer.TransferEvent;
  import org.eclipse.aether.transfer.TransferResource;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * A simplistic transfer listener that logs uploads/downloads to the console.
   */
  public class ConsoleTransferListener
      extends AbstractTransferListener
  {
  
      private final PrintStream out;
  
      private final Map<TransferResource, Long> downloads = new ConcurrentHashMap<>();
  
      private int lastLength;
  
      public ConsoleTransferListener()
      {
          this( null );
      }
  
      public ConsoleTransferListener( PrintStream out )
      {
          this.out = ( out != null ) ? out : System.out;
      }
  
      @Override
      public void transferInitiated( TransferEvent event )
      {
          requireNonNull( event, "event cannot be null" );
          String message = event.getRequestType() == TransferEvent.RequestType.PUT ? "Uploading" : "Downloading";
  
          out.println( message + ": " + event.getResource().getRepositoryUrl() + event.getResource().getResourceName() );
      }
  
      @Override
      public void transferProgressed( TransferEvent event )
      {
          requireNonNull( event, "event cannot be null" );
          TransferResource resource = event.getResource();
          downloads.put( resource, event.getTransferredBytes() );
  
          StringBuilder buffer = new StringBuilder( 64 );
  
          for ( Map.Entry<TransferResource, Long> entry : downloads.entrySet() )
          {
              long total = entry.getKey().getContentLength();
              long complete = entry.getValue();
  
              buffer.append( getStatus( complete, total ) ).append( "  " );
          }
  
          int pad = lastLength - buffer.length();
          lastLength = buffer.length();
          pad( buffer, pad );
          buffer.append( '\r' );
  
          out.print( buffer );
      }
  
      private String getStatus( long complete, long total )
      {
          if ( total >= 1024 )
          {
              return toKB( complete ) + "/" + toKB( total ) + " KB ";
          }
          else if ( total >= 0 )
         {
             return complete + "/" + total + " B ";
         }
         else if ( complete >= 1024 )
         {
             return toKB( complete ) + " KB ";
         }
         else
         {
             return complete + " B ";
         }
     }
 
     private void pad( StringBuilder buffer, int spaces )
     {
         String block = "                                        ";
         while ( spaces > 0 )
         {
             int n = Math.min( spaces, block.length() );
             buffer.append( block, 0, n );
             spaces -= n;
         }
     }
 
     @Override
     public void transferSucceeded( TransferEvent event )
     {
         requireNonNull( event, "event cannot be null" );
         transferCompleted( event );
 
         TransferResource resource = event.getResource();
         long contentLength = event.getTransferredBytes();
         if ( contentLength >= 0 )
         {
             String type = ( event.getRequestType() == TransferEvent.RequestType.PUT ? "Uploaded" : "Downloaded" );
             String len = contentLength >= 1024 ? toKB( contentLength ) + " KB" : contentLength + " B";
 
             String throughput = "";
             long duration = System.currentTimeMillis() - resource.getTransferStartTime();
             if ( duration > 0 )
             {
                 long bytes = contentLength - resource.getResumeOffset();
                 DecimalFormat format = new DecimalFormat( "0.0", new DecimalFormatSymbols( Locale.ENGLISH ) );
                 double kbPerSec = ( bytes / 1024.0 ) / ( duration / 1000.0 );
                 throughput = " at " + format.format( kbPerSec ) + " KB/sec";
             }
 
             out.println( type + ": " + resource.getRepositoryUrl() + resource.getResourceName() + " (" + len
                 + throughput + ")" );
         }
     }
 
     @Override
     public void transferFailed( TransferEvent event )
     {
         requireNonNull( event, "event cannot be null" );
         transferCompleted( event );
 
         if ( !( event.getException() instanceof MetadataNotFoundException ) )
         {
             event.getException().printStackTrace( out );
         }
     }
 
     private void transferCompleted( TransferEvent event )
     {
         requireNonNull( event, "event cannot be null" );
         downloads.remove( event.getResource() );
 
         StringBuilder buffer = new StringBuilder( 64 );
         pad( buffer, lastLength );
         buffer.append( '\r' );
         out.print( buffer );
     }
 
     public void transferCorrupted( TransferEvent event )
     {
         requireNonNull( event, "event cannot be null" );
         event.getException().printStackTrace( out );
     }
 
     @SuppressWarnings( "checkstyle:magicnumber" )
     protected long toKB( long bytes )
     {
         return ( bytes + 1023 ) / 1024;
     }
 
 }