package org.apache.maven.scm.provider.hg;
   
   /*
    * 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.
   */
  
  import org.apache.maven.scm.ScmException;
  import org.apache.maven.scm.ScmFileStatus;
  import org.apache.maven.scm.provider.hg.command.HgCommandConstants;
  import org.apache.maven.scm.provider.hg.command.HgConsumer;
  import org.codehaus.plexus.util.cli.Commandline;
  
  import java.io.File;
  
  /**
   * Check hg installation.
   *
   * @author <a href="mailto:thurner.rupert@ymono.net">thurner rupert</a>
   * @author <a href="mailto:ryan@darksleep.com">ryan daum</a>
   *
   */
  public class HgConfig
  {
      //Minimum version for the Hg SCM
      private static final String HG_REQ = "0.9.2";
  
      // The string which indicates the beginning of the Mercurial line
      private static final String HG_VERSION_TAG = "Mercurial Distributed SCM (version ";
  
      // URL to download mercurial from
      private static final String HG_INSTALL_URL = "'http://www.selenic.com/mercurial/wiki/index.cgi/Download'";
  
      //Configuration to check with default values (not installed)
      private HgVersionConsumer hgVersion = new HgVersionConsumer( null );
  
      HgConfig( File workingDir )
      {
          try
          {
              hgVersion = getHgVersion( workingDir );
          }
          catch ( ScmException e )
          {
              //Ignore -  is not installed.
              //This is already recorded thus we do not generate more info.
          }
  
      }
  
      /**
       * @return True if one can run basic hg commands
       */
      private boolean isInstalled()
      {
          return hgVersion.isVersionOk( HG_REQ );
      }
  
      /**
       * @return True if all modules for hg are installed.
       */
      private boolean isComplete()
      {
          return isInstalled();
      }
  
      // Consumer to find the Mercurial version
      public static HgVersionConsumer getHgVersion( File workingDir )
          throws ScmException
      {
          String[] versionCmd = new String[]{ HgCommandConstants.VERSION };
          HgVersionConsumer consumer = new HgVersionConsumer( HG_VERSION_TAG );
          Commandline cmd = HgUtils.buildCmd( workingDir, versionCmd );
  
          // Execute command
          HgUtils.executeCmd( consumer, cmd );
  
          // Return result
          return consumer;
      }
  
  
      /**
       * Iterate through two dot-notation version strings, normalize them to the same length, then
       * do alphabetic comparison
      *
      * @param version1
      * @param version2
      * @return true if version2 is greater than version1
      */
     private static boolean compareVersion( String version1, String version2 )
     {
         int l1, l2;
         String v1, v2;
 
         v1 = version1;
         v2 = version2;
         l1 = version1.length();
         l2 = version2.length();
 
         if ( l1 > l2 )
         {
             for ( int x = l2; x >= l1; x-- )
             {
                 v2 += ' ';
             }
         }
         if ( l2 > l1 )
         {
             for ( int x = l1; x <= l2; x++ )
             {
                 v1 += ' ';
             }
         }
 
         return v2.compareTo( v1 ) >= 0;
     }
 
 
     /**
      * Get version of the executable.
      * Version is resolved by splitting the line starting with the version tag and finding
      * the second last word.
      */
     private static class HgVersionConsumer
         extends HgConsumer
     {
 
         private String versionStr = "NA";
 
         private String versionTag;
 
         HgVersionConsumer( String versionTag )
         {
             this.versionTag = versionTag;
         }
 
         public void doConsume( ScmFileStatus status, String line )
         {
             if ( line.startsWith( versionTag ) )
             {
                 String[] elements = line.split( " " );
                 versionStr = elements[elements.length - 1].split( "\\)" )[0];
             }
         }
 
         String getVersion()
         {
             return versionStr;
         }
 
         boolean isVersionOk( String version )
         {
             // build one number out of the whole version #
 
             return compareVersion( version, versionStr );
         }
     }
 
     private String getInstalledStr()
     {
         if ( isComplete() )
         {
             return "valid and complete.";
         }
         return ( isInstalled() ? "incomplete. " : "invalid. " ) + "Consult " + HG_INSTALL_URL;
     }
 
     public String toString( File workingDir )
     {
         boolean hgOk = hgVersion.isVersionOk( HG_REQ );
         return "\n  Your Hg installation seems to be " + getInstalledStr() + "\n    Hg version: "
             + hgVersion.getVersion() + ( hgOk ? " (OK)" : " (May be INVALID)" ) + "\n";
     }
 }