/**
    * Copyright 2005-2006 the original author or authors.
    *
    * Licensed under the Gnu General Pubic 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.opensource.org/licenses/gpl-license.php
    *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   * See the Gnu General Public License for more details.
   */
  package org.figure8.join.services.scripting.groovy;
  
  import org.figure8.join.core.InvalidParameterException;
  import org.figure8.join.services.scripting.ScriptLauncher;
  import org.figure8.join.services.scripting.ScriptException;
  import org.figure8.join.util.LogUtil;
  
  import groovy.lang.Script;
  import groovy.lang.Binding;
  import groovy.lang.GroovyShell;
  import org.apache.commons.logging.Log;
  import org.codehaus.groovy.control.CompilationFailedException;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.util.Properties;
  import java.util.Enumeration;
  /**
   * Extension of {@link ScriptLauncher} dedicated to the Groovy script
   * language (see http://groovy.codehaus.org). This implementation lets
   * you wrap the execution of a Groovy script within a ScriptLauncher.
   * @author <a href="mailto:laurent.broudoux@free.fr">Laurent Broudoux</a>
   * @version $Revision: 1.2 $
   */
  public class GroovyScriptLauncher extends ScriptLauncher{
  
     // Static -------------------------------------------------------------------
  
     /** Get a commons logger. */
     private static final Log log = LogUtil.getLog(GroovyScriptLauncher.class);
  
  
     // Attributes ---------------------------------------------------------------
  
     /** A handler on parsed script file (for optimization) */
     private Script groovyScript = null;
     /** Copy of base class value (for optimization on parsing) */
     private String scriptPath = super.getScriptPath();
  
  
     // Constructors -------------------------------------------------------------
  
     /** Creates a new instance of GroovyScriptLauncher. */
     public GroovyScriptLauncher(){
     }
  
     /**
      * Creates a new instance of GroovyScriptLauncher with script path.
      * @param scriptPath the path of script to later execute
      * @throws InvalidParameterException if path cannot be accessed
      */
     public GroovyScriptLauncher(String scriptPath) throws InvalidParameterException{
        super(scriptPath);
     }
  
  
     // Implementation of ScriptLauncher -----------------------------------------
  
     /**
      * Run the Groovy script file identified by <code>scriptPath</code> inner
      * field. Properties passed as param are injected into the Groovy script
      * as binding properties. Script can directly use them using the ${property_name}
      * form. <b>Warning: </b> "." in properties keys passing in are modified
      * into "_" before injected. This is necessary because "." as special meaning
      * in Groovy (nested field) that we don't want to have here.
      * @param properties
      */
     public void runScript(Properties properties) throws ScriptException{
        // Prepare a writer for logging.
        PrintWriter writer = null;
        try{
           // Parse script file only if necessary.
           if (scriptHasChanged()){
              // Create new shell & script.
              Thread th = Thread.currentThread();
              GroovyShell shell = new GroovyShell(th.getContextClassLoader());
              log.info("Parsing Groovy script '" + getScript().getPath() + "'");
              groovyScript = shell.parse(getScript());
           }
  
           // Create and fill Binding.
           Binding binding = new Binding();
           Enumeration keys = properties.keys();
           while (keys != null && keys.hasMoreElements()){
              String key = (String)keys.nextElement();
             String value = properties.getProperty(key);
             // Dot represents a nested field in groovy,
             // replace dot by underscore into property names.
             if (log.isDebugEnabled())
                log.debug("Adding property '" + key.replace('.', '_') + "' (" + value + ") as binding property");
             binding.setProperty(key.replace('.', '_'), value);
          }
 
          // Use a logger if output stream is available.
          if (getLogOutputStream() != null){
             writer = new PrintWriter(getLogOutputStream());
             binding.setVariable("out", writer);
          }
 
          // Launch execution.
          groovyScript.setBinding(binding);
          groovyScript.run();
       }
       catch (CompilationFailedException cfe){
          // Log and wrap into a ScriptException.
          log.error("The compilation of '" + scriptPath + "' Groovy script failed !");
          log.error("Here's the detailed message: " + cfe.getMessage());
          throw new ScriptException("Compilation of Groovy script failed", cfe);
       }
       catch (IOException ioe){
          // Log and wrap into a ScriptException.
          log.error("IOException while accessing Groovy script '" + scriptPath + "'");
          throw new ScriptException("IOException while accessing Groovy script", ioe);
       }
       finally{
          // Close writer on log file.
          if (writer != null)
             writer.close();
       }
    }
 
 
    // Private ------------------------------------------------------------------
 
    /** @return True if script has changed since last parsing */
    private boolean scriptHasChanged(){
       // Has path to script file changed ?
       if (groovyScript== null || !getScriptPath().equals(scriptPath)){
          log.info("Script has changed, getting " + getScriptPath());
          scriptPath = getScriptPath();
          return true;
       }
       return false;
    }
 }