/*
    * LICENSE
    *
    * "THE BEER-WARE LICENSE" (Revision 42):
    * "Sven Strittmatter" <ich@weltraumschaf.de> wrote this file.
    * As long as you retain this notice you can do whatever you want with
    * this stuff. If we meet some day, and you think this stuff is worth it,
    * you can buy me a beer in return.
    */
  package org.jenkinsci.plugins.darcs;
  
  import hudson.FilePath;
  import hudson.Launcher;
  import hudson.Launcher.ProcStarter;
  import hudson.util.ArgumentListBuilder;
  import java.io.ByteArrayOutputStream;
  import java.util.Map;
  
  /**
   * Abstracts the Darcs command.
   *
   * @author Sven Strittmatter <ich@weltraumschaf.de>
   */
  public class DarcsCmd {
  
      /**
       * `darcs changes` command.
       */
      private static final String CMD_CHANGES = "changes";
      /**
       * `darcs pull` command.
       */
      private static final String CMD_PULL = "pull";
      /**
       * `darcs get` command.
       */
      private static final String CMD_GET = "get";
      // Command options
      private static final String OPT_REPO = "--repo=";
      private static final String OPT_XML_OUTPUT = "--xml-output";
      private static final String OPT_SUMMARY = "--summary";
      private static final String OPT_LAST = "--last=";
      private static final String OPT_REPODIR = "--repodir=";
      private static final String OPT_COUNT = "--count";
      private static final String OPT_ALL = "--all";
      private static final String OPT_VERBOSE = "--verbose";
      /**
       * Used to start a process.
       */
      private final Launcher launcher;
      /**
       * Name of the Darcs executable binary.
       */
      private final String darcsExe;
      /**
       * Environment variables.
       */
      private final Map<String, String> envs;
      private final FilePath workingDir;
  
      /**
       * Creates a Darcs command object.
       *
       * @param launcher starts a process
       * @param envs environment variables
       * @param darcsExe executable name
       */
      public DarcsCmd(final Launcher launcher, final Map<String, String> envs, final String darcsExe, final FilePath workingDir) {
          super();
          this.envs = envs;
          this.launcher = launcher;
          this.darcsExe = darcsExe;
          this.workingDir = workingDir;
      }
  
      /**
       * Creates process starter.
       *
       * @param args builds argument list for command
       * @return a process starter object
       */
      public ProcStarter createProc(final ArgumentListBuilder args) {
          final ProcStarter proc = launcher.launch();
          proc.cmds(args);
          proc.envs(envs);
          proc.pwd(workingDir);
          return proc;
      }
  
      public ByteArrayOutputStream lastSummarizedChanges(final String repo, final int n) throws DarcsCmdException {
          return getChanges(repo, true, n);
      }
  
      public ByteArrayOutputStream allSummarizedChanges(final String repo) throws DarcsCmdException {
          return getChanges(repo, true);
      }
  
      public ByteArrayOutputStream allChanges(final String repo) throws DarcsCmdException {
          return getChanges(repo, false);
     }
 
     private ByteArrayOutputStream getChanges(final String repo, final boolean summarize) throws DarcsCmdException {
         return getChanges(repo, summarize, 0);
     }
 
     private ByteArrayOutputStream getChanges(final String repo, final boolean summarize, final int n)
             throws DarcsCmdException {
         final ArgumentListBuilder args = new ArgumentListBuilder();
         args.add(darcsExe)
                 .add(CMD_CHANGES)
                 .add(OPT_REPO + repo)
                 .add(OPT_XML_OUTPUT);
 
         if (summarize) {
             args.add(OPT_SUMMARY);
         }
 
         if (n > 0) {
             args.add(OPT_LAST + n);
         }
 
         final ProcStarter proc = createProc(args);
         final ByteArrayOutputStream baos = new ByteArrayOutputStream();
         proc.stdout(baos);
 
         try {
             final int ret = proc.join();
 
             if (0 != ret) {
                 throw new DarcsCmdException("can not do darcs changes in repo " + repo);
             }
         } catch (Exception ex) {
             throw new DarcsCmdException("can not do darcs changes in repo " + repo, ex);
         }
 
         return baos;
     }
 
     public int countChanges(final String repo) throws DarcsCmdException {
         final ArgumentListBuilder args = new ArgumentListBuilder();
         args.add(darcsExe)
                 .add(CMD_CHANGES)
                 .add(OPT_REPODIR + repo)
                 .add(OPT_COUNT);
 
         final ProcStarter proc = createProc(args);
         final ByteArrayOutputStream baos = new ByteArrayOutputStream();
         proc.stdout(baos);
 
         try {
             final int ret = proc.join();
 
             if (0 != ret) {
                 throw new DarcsCmdException("can not do darcs changes in repo " + repo);
             }
         } catch (Exception ex) {
             throw new DarcsCmdException("can not do darcs changes in repo " + repo, ex);
         }
 
         return Integer.parseInt(baos.toString().trim());
     }
 
     public void pull(final String repo, final String from) throws DarcsCmdException {
         final ArgumentListBuilder args = new ArgumentListBuilder();
         args.add(darcsExe)
                 .add(CMD_PULL)
                 .add(from)
                 .add(OPT_REPODIR + repo)
                 .add(OPT_ALL)
                 .add(OPT_VERBOSE);
 
         try {
             final ProcStarter proc = createProc(args);
             proc.stdout(this.launcher.getListener());
             final int ret = proc.join();
 
             if (0 != ret) {
                 throw new DarcsCmdException(String.format("Can't do darcs changes in repo %s! Return code: %d",
                         repo, ret));
             }
         } catch (Exception ex) {
             throw new DarcsCmdException(String.format("Can't do darcs changes in repo %s!", repo), ex);
         }
     }
 
     /**
      * Do a fresh checkout of a repository.
      *
      * @param repo where to checkout
      * @param from from where to get the repository
      * @throws DarcsCmd.DarcsCmdException if can't do checkout
      */
     public void get(final String repo, final String from) throws DarcsCmdException {
         final ArgumentListBuilder args = new ArgumentListBuilder();
         args.add(darcsExe)
                 .add(CMD_GET)
                 .add(from)
                 .add(repo);
 
         try {
             final ProcStarter proc = createProc(args);
             proc.stdout(this.launcher.getListener());
             final int ret = proc.join();
 
             if (0 != ret) {
                 throw new DarcsCmdException(String.format("Getting repo with args %s failed! Return code: %d",
                         args.toStringWithQuote(), ret));
             }
         } catch (Exception ex) {
             throw new DarcsCmdException(String.format("Can't get repo with args: %s", args.toStringWithQuote()), ex);
         }
     }
 
     /**
      * Darcs command exception.
      */
     public static class DarcsCmdException extends RuntimeException {
 
         /**
          * Creates exception with message.
          *
          * @param string exception message
          */
         public DarcsCmdException(final String string) {
             super(string);
         }
 
         /**
          * Creates exception with message and a previous exception.
          *
          * @param string exception message
          * @param thrwbl previous exception
          */
         public DarcsCmdException(final String string, final Throwable thrwbl) {
             super(string, thrwbl);
         }
     }
 }