/*
    * 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.scm.provider.git.gitexe.command.info;
  
  import java.io.File;
  import java.util.Collections;
  import java.util.LinkedList;
  import java.util.List;
  
  import org.apache.maven.scm.CommandParameter;
  import org.apache.maven.scm.CommandParameters;
  import org.apache.maven.scm.ScmException;
  import org.apache.maven.scm.ScmFileSet;
  import org.apache.maven.scm.ScmResult;
  import org.apache.maven.scm.command.AbstractCommand;
  import org.apache.maven.scm.command.info.InfoItem;
  import org.apache.maven.scm.command.info.InfoScmResult;
  import org.apache.maven.scm.provider.ScmProviderRepository;
  import org.apache.maven.scm.provider.git.command.GitCommand;
  import org.apache.maven.scm.provider.git.gitexe.command.GitCommandLineUtils;
  import org.codehaus.plexus.util.cli.CommandLineUtils;
  import org.codehaus.plexus.util.cli.Commandline;
  
  /**
   * Uses {@code git log} command to retrieve info about the most recent commits related to specific files.
   *
   * @author Olivier Lamy
   * @since 1.5
   */
  public class GitInfoCommand extends AbstractCommand implements GitCommand {
  
      public static final int NO_REVISION_LENGTH = -1;
  
      @Override
      protected ScmResult executeCommand(
              ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters) throws ScmException {
  
          Commandline baseCli = GitCommandLineUtils.getBaseGitCommandLine(fileSet.getBasedir(), "log");
          baseCli.createArg().setValue("-1"); // only most recent commit matters
          baseCli.createArg().setValue("--no-merges"); // skip merge commits
          baseCli.addArg(GitInfoConsumer.getFormatArgument());
  
          List<InfoItem> infoItems = new LinkedList<>();
          if (fileSet.getFileList().isEmpty()) {
              infoItems.add(executeInfoCommand(baseCli, parameters, fileSet.getBasedir()));
          } else {
              // iterate over files
              for (File scmFile : fileSet.getFileList()) {
                  baseCli = GitCommandLineUtils.getBaseGitCommandLine(fileSet.getBasedir(), "log");
                  baseCli.createArg().setValue("-1"); // only most recent commit matters
                  baseCli.createArg().setValue("--no-merges"); // skip merge commits
                  baseCli.addArg(GitInfoConsumer.getFormatArgument());
                  // Insert a separator to make sure that files aren't interpreted as part of the version spec
                  baseCli.createArg().setValue("--");
                  GitCommandLineUtils.addTarget(baseCli, Collections.singletonList(scmFile));
                  infoItems.add(executeInfoCommand(baseCli, parameters, scmFile));
              }
          }
          return new InfoScmResult(baseCli.toString(), infoItems);
      }
  
      protected InfoItem executeInfoCommand(Commandline cli, CommandParameters parameters, File scmFile)
              throws ScmException {
          GitInfoConsumer consumer = new GitInfoConsumer(scmFile.toPath(), getRevisionLength(parameters));
          CommandLineUtils.StringStreamConsumer stderr = new CommandLineUtils.StringStreamConsumer();
          int exitCode = GitCommandLineUtils.execute(cli, consumer, stderr);
          if (exitCode != 0) {
              throw new ScmException("The git log command failed: " + cli.toString() + " returned " + stderr.getOutput());
          }
          return consumer.getInfoItem();
      }
  
      /**
       * Get the revision length from the parameters.
       *
       * @param parameters
       * @return -1 if parameter {@link CommandParameter.SCM_SHORT_REVISION_LENGTH} is absent, <br>
       *         and otherwise - the length to be applied for the revision formatting
       * @throws ScmException
       * @since 1.7
       */
      private static int getRevisionLength(final CommandParameters parameters) throws ScmException {
          if (parameters == null) {
             return NO_REVISION_LENGTH;
         } else {
             return parameters.getInt(CommandParameter.SCM_SHORT_REVISION_LENGTH, NO_REVISION_LENGTH);
         }
     }
 }