/*
    * #%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.BufferedReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.StringReader;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import com.aragost.javahg.commands.ManifestMergeOracle;
  import com.aragost.javahg.commands.UpdateResult;
  import com.google.common.io.ByteStreams;
  
  /**
   * A helper class to parse output from update and merge commands.
   */
  public class UpdateMergeHelper {
  
      private static final Pattern MANIFEST_MERGE_PATTERN = Pattern.compile("remote changed (.*) which local deleted\n"
              + "use \\(c\\)hanged version or leave \\(d\\)eleted\\? ");
  
      private InputStream stdout;
  
      private ManifestMergeOracle oracle;
  
      private AbstractCommand command;
  
      public UpdateMergeHelper(InputStream stdout, ManifestMergeOracle oracle, AbstractCommand command) {
          this.stdout = stdout;
          this.oracle = oracle;
          this.command = command;
      }
  
      public void merge() throws IOException {
          processManifestMergeConflictPrompting();
      }
  
      public UpdateResult update() throws IOException {
          String output = processManifestMergeConflictPrompting();
          BufferedReader reader = new BufferedReader(new StringReader(output));
          String line;
          UpdateResult result = null;
          while ((line = reader.readLine()) != null) {
              if (line.startsWith("merging ")) {
                  // Just ignore
              } else if (line.equals("use 'hg resolve' to retry unresolved file merges")) {
                  // Ignore
              } else {
                  result = UpdateResult.fromLine(line);
              }
          }
          if (result == null) {
              throw new IllegalStateException("No 'update' line found in output");
          }
          return result;
      }
  
      private String processManifestMergeConflictPrompting() throws IOException {
          if (this.oracle != null) {
              this.oracle.getMissingAnswers().clear();
          }
  
          String output = null;
          while (true) {
              output = new String(ByteStreams.toByteArray(this.stdout));
              Matcher matcher = MANIFEST_MERGE_PATTERN.matcher(output);
              if (matcher.matches()) {
                  if (oracle == null) {
                      throw new RuntimeException("Manifest merge conflict, but no oracle");
                  }
                  String filename = output.substring(matcher.start(1), matcher.end(1));
                  String answer = oracle.ask(filename);
                  this.command.sendLine(answer);
                  this.command.reopenOutputChannelStream();
             } else {
                 break;
             }
         }
         return output;
     }
 }