/*
    * 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.
   */
  package org.apache.maven.cli.transfer;
  
  import java.io.PrintStream;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.LinkedHashMap;
  import java.util.Locale;
  import java.util.Map;
  
  import org.eclipse.aether.transfer.TransferCancelledException;
  import org.eclipse.aether.transfer.TransferEvent;
  import org.eclipse.aether.transfer.TransferResource;
  
  /**
   * Console download progress meter.
   *
   * @author <a href="mailto:brett@apache.org">Brett Porter</a>
   */
  public class ConsoleMavenTransferListener extends AbstractMavenTransferListener {
  
      private final Map<TransferResourceIdentifier, TransferResourceAndSize> transfers =
              Collections.synchronizedMap(new LinkedHashMap<TransferResourceIdentifier, TransferResourceAndSize>());
  
      private final boolean printResourceNames;
      private int lastLength;
  
      public ConsoleMavenTransferListener(PrintStream out, boolean printResourceNames) {
          super(out);
          this.printResourceNames = printResourceNames;
      }
  
      @Override
      public void transferInitiated(TransferEvent event) {
          overridePreviousTransfer(event);
  
          super.transferInitiated(event);
      }
  
      @Override
      public void transferCorrupted(TransferEvent event) throws TransferCancelledException {
          overridePreviousTransfer(event);
  
          super.transferCorrupted(event);
      }
  
      @Override
      public void transferProgressed(TransferEvent event) throws TransferCancelledException {
          TransferResource resource = event.getResource();
          transfers.put(
                  new TransferResourceIdentifier(resource),
                  new TransferResourceAndSize(resource, event.getTransferredBytes()));
  
          StringBuilder buffer = new StringBuilder(128);
          buffer.append("Progress (").append(transfers.size()).append("): ");
  
          synchronized (transfers) {
              Iterator<TransferResourceAndSize> entries = transfers.values().iterator();
              while (entries.hasNext()) {
                  TransferResourceAndSize entry = entries.next();
                  long total = entry.resource.getContentLength();
                  Long complete = entry.transferredBytes;
                  buffer.append(getStatus(entry.resource.getResourceName(), complete, total));
                  if (entries.hasNext()) {
                      buffer.append(" | ");
                  }
              }
          }
  
          int pad = lastLength - buffer.length();
          lastLength = buffer.length();
          pad(buffer, pad);
          buffer.append('\r');
          out.print(buffer);
          out.flush();
      }
  
      private String getStatus(String resourceName, long complete, long total) {
          FileSizeFormat format = new FileSizeFormat(Locale.ENGLISH);
          StringBuilder status = new StringBuilder();
  
          if (printResourceNames) {
             status.append(resourceName(resourceName));
             status.append(" (");
         }
 
         status.append(format.formatProgress(complete, total));
 
         if (printResourceNames) {
             status.append(")");
         }
 
         return status.toString();
     }
 
     private String resourceName(String resourceName) {
         if (resourceName == null || resourceName.trim().isEmpty()) {
             return "";
         }
         final int pos = resourceName.lastIndexOf("/");
         if (pos == -1 || pos == resourceName.length() - 1) {
             return "";
         }
         return resourceName.substring(pos + 1);
     }
 
     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) {
         transfers.remove(new TransferResourceIdentifier(event.getResource()));
         overridePreviousTransfer(event);
 
         super.transferSucceeded(event);
     }
 
     @Override
     public void transferFailed(TransferEvent event) {
         transfers.remove(new TransferResourceIdentifier(event.getResource()));
         overridePreviousTransfer(event);
 
         super.transferFailed(event);
     }
 
     private void overridePreviousTransfer(TransferEvent event) {
         if (lastLength > 0) {
             StringBuilder buffer = new StringBuilder(128);
             pad(buffer, lastLength);
             buffer.append('\r');
             out.print(buffer);
             out.flush();
             lastLength = 0;
         }
     }
 
     private final class TransferResourceAndSize {
 
         private final TransferResource resource;
         private final long transferredBytes;
 
         private TransferResourceAndSize(TransferResource resource, long transferredBytes) {
             this.resource = resource;
             this.transferredBytes = transferredBytes;
         }
     }
 }