/*
    * #%L
    * JavaHg
    * %%
    * Copyright (C) 2011 aragost Trifork ag
    * %%
    * Permission is hereby granted, free of charge, to any person obtaining a copy
    * of this software and associated documentation files (the "Software"), to deal
    * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   * 
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   * 
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   * #L%
   */
  package com.aragost.javahg.internals;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.util.Collections;
  import java.util.List;
  
  import com.aragost.javahg.Changeset;
  import com.aragost.javahg.Repository;
  import com.aragost.javahg.commands.ExecutionException;
  import com.aragost.javahg.commands.LogCommand;
  import com.google.common.collect.Lists;
  import com.google.common.io.ByteStreams;
  
  public class PullPushHelper {
  
      private static final byte[] BEGIN = "list of changesets:\n".getBytes();
      private static final byte[] BEGIN_FALLBACK = "adding changesets\n"
              .getBytes();
      private static final byte[] LINE_BEGIN = "add changeset ".getBytes();
      private static final byte[] REMOTE_ERROR = "remote: error: ".getBytes();
  
      public static List<Changeset> parseStream(AbstractCommand command,
              HgInputStream stream) throws IOException {
      	Repository repo = command.getRepository();
          List<Changeset> result;
  
          // Pulling locally the full nodes are written after
          // "list of changesets:"
          // Over HTTP this isn't written.
          // In either case 12 character node prefixes are printed after
          // "adding changesets".
          // If possible use first case, otherwise fall back to node prefixes.
  
          // Make a copy
          ByteArrayOutputStream bos = new ByteArrayOutputStream();
          ByteStreams.copy(stream, bos);
          stream.consumeAll();
          stream = new HgInputStream(new ByteArrayInputStream(bos.toByteArray()), repo.newDecoder());
  
          if (stream.find(BEGIN)) {
              result = Lists.newArrayList();
              while (!stream.isEof() && !stream.match(BEGIN_FALLBACK)) {
                  result.add(repo.changeset(stream.textUpTo('\n')));
              }
          } else {
              stream = new HgInputStream(new ByteArrayInputStream(bos.toByteArray()), repo.newDecoder());
  
              List<String> nodePrefixes = Lists.newArrayList();
  
              if (stream.find(BEGIN_FALLBACK)) {
                  if (stream.find(LINE_BEGIN)) {
                      // 12 Character node prefix
                      nodePrefixes.add(stream.textUpTo('\n'));
                  }
              }
              if (nodePrefixes.isEmpty()) {
                  result = Collections.emptyList();
              } else {
                  result = LogCommand
                          .on(repo)
                          .rev(nodePrefixes.toArray(new String[nodePrefixes
                                  .size()])).execute();
              }
          }
  
          stream = new HgInputStream(new ByteArrayInputStream(bos.toByteArray()), repo.newDecoder());
  
          if (stream.find(REMOTE_ERROR)) {
              throw new ExecutionException(command, stream.textUpTo('\n'));
          }
  
          return result;
     }
 }