/*

  * $Source$

  * $Revision$

  *

  * Copyright (C) 2005 Tim Pizey

  *

  * Part of Melati (http://melati.org), a framework for the rapid

  * development of clean, maintainable web applications.

  *

  * Melati is free software; Permission is granted to copy, distribute

  * and/or modify this software under the terms either:

  *

  * a) the GNU General Public License as published by the Free Software

  *    Foundation; either version 2 of the License, or (at your option)

  *    any later version,

  *

  *    or

  *

  * b) any version of the Melati Software License, as published

  *    at http://melati.org

  *

  * You should have received a copy of the GNU General Public License and

  * the Melati Software License along with this program;

  * if not, write to the Free Software Foundation, Inc.,

  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the

  * GNU General Public License and visit http://melati.org to obtain the

  * Melati Software License.

  *

  * Feel free to contact the Developers of Melati (http://melati.org),

  * if you would like to work out a different arrangement than the options

  * outlined here.  It is our intention to allow Melati to be used by as

  * wide an audience as possible.

  *

  * 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.

  *

  * Contact details for copyright holder:

  *

  *     Tim Pizey <timp At paneris.org>

  *     http://paneris.org/~timp

  */

 package org.melati.app;

 import java.io.File;

 import java.io.FileNotFoundException;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.io.OutputStreamWriter;

 import java.io.PrintStream;

 import java.util.Properties;

 import org.melati.Melati;

 import org.melati.MelatiConfig;

 import org.melati.PoemContext;

 import org.melati.poem.PoemDatabaseFactory;

 import org.melati.poem.util.ArrayUtils;

 import org.melati.util.MelatiException;

 import org.melati.util.MelatiIOException;

 import org.melati.util.MelatiSimpleWriter;

 import org.melati.util.MelatiWriter;

 /**

  * ConfigApp is the simplest way to use Melati.

  * 

  * All a ConfigApp does is to configure a Melati. Importantly it does not

  * establish a Poem session leaving you to do this for yourself.

  * 

  * If you want a POEM session established, please extend {@link AbstractPoemApp}.

  * 

  * ConfigApp does set up a basic {@link PoemContext} with the Method set, but

  * not the POEM logicaldatabase, table or troid.

  * 

  * The arguments are expected to end with a freeform string telling your

  * application what it is meant to do. This is automatically made available in

  * templates as <TT>$melati.Method</TT>.

  * 

  * You can change the way these things are determined by overriding

  * {@link #poemContext}.

  */

 public abstract class AbstractConfigApp implements App {

   protected static MelatiConfig melatiConfig;

   protected PrintStream output = System.out;

   /**

    * Initialise.

    * 

    * @param args

    *          the command line arguments

    * @return a newly created Melati

    * @throws MelatiException

    *           if something goes wrong during initialisation

    */

   public Melati init(String[] args) throws MelatiException {

       melatiConfig = melatiConfig();

     String[] argumentsWithoutOutput = applyNamedArguments(args);

     MelatiWriter out = new MelatiSimpleWriter(new OutputStreamWriter(output));

     Melati melati = new Melati(melatiConfig, out);

     melati.setArguments(argumentsWithoutOutput);

     melati.setPoemContext(poemContext(melati));

     return melati;

   }

   /**

    * Clean up at end of run. Overridden in PoemApp.

    * 

    * @param melati

    *          the melati

    * @throws IOException if there is an io problem

    */

   public void term(Melati melati) throws IOException {

     melati.write();

   }

   /**

    * Set application properties from the default properties file.

    * 

    * This method will look for a properties file called

    * <tt>org.melati.MelatiConfig.properties</tt>; if it finds that the

    * AccessHandler is an Http handler it will set the access handler to

    * <code>OpenAccessHandler</code>.

    * 

    * Similarly ServletTemplateEngine is changed to TemplateEngine.

    *  

    * To override any setting from MelatiConfig.properties, simply override this

    * method and return a vaild MelatiConfig.

    * 

    * eg to use a different AccessHandler from the default:

    * 

    * <PRE>

    * protected MelatiConfig melatiConfig() throws MelatiException {

    *   MelatiConfig config = super.melatiConfig();

    *   config.setAccessHandler(new YourAccessHandler());

    *   return config;

    * }

    * </PRE>

    * 

    * @throws MelatiException

    *           if anything goes wrong with Melati

    */

   protected MelatiConfig melatiConfig() throws MelatiException {

     Properties servletProperties = MelatiConfig.getProperties();

     if (servletProperties.getProperty("org.melati.MelatiConfig.templateEngine").equals(

         "org.melati.template.webmacro.WebmacroServletTemplateEngine"))

       servletProperties.setProperty("org.melati.MelatiConfig.templateEngine", 

           "org.melati.template.webmacro.WebmacroTemplateEngine");

     if (servletProperties.getProperty("org.melati.MelatiConfig.templateEngine").equals(

         "org.melati.template.webmacro.VelocityServletTemplateEngine"))

       servletProperties.setProperty("org.melati.MelatiConfig.templateEngine", 

           "org.melati.template.webmacro.VelocityTemplateEngine");

     if (servletProperties.getProperty("org.melati.MelatiConfig.templateEngine").equals(

         "org.melati.template.webmacro.FreemarkerServletTemplateEngine"))

       servletProperties.setProperty("org.melati.MelatiConfig.templateEngine", 

           "org.melati.template.webmacro.FreemarkerTemplateEngine");

     if (servletProperties.getProperty("org.melati.MelatiConfig.accessHandler").equals(

         "org.melati.login.HttpBasicAuthenticationAccessHandler"))

       servletProperties.setProperty("org.melati.MelatiConfig.accessHandler", 

           "org.melati.login.OpenAccessHandler");

     if (servletProperties.getProperty("org.melati.MelatiConfig.accessHandler").equals(

         "org.melati.login.HttpSessionAccessHandler"))

       servletProperties.setProperty("org.melati.MelatiConfig.accessHandler", 

           "org.melati.login.OpenAccessHandler");

     MelatiConfig config = new MelatiConfig(servletProperties);

     return config;

   }

   /**

    * Do our thing.

    */

   public void run(String[] args) throws Exception {

     Melati melati = init(args);

     try { 

       doConfiguredRequest(melati);

     } finally {  

       term(melati);

       PoemDatabaseFactory.getPoemShutdownThread().run();

     }

   }

   /**

    * This method <b>SHOULD</b> be overidden.

    * 

    * @return the System Administrators name.

    */

   public String getSysAdminName() {

     return "nobody";

   }

   /**

    * This method <b>SHOULD</b> be overidden.

    * 

    * @return the System Administrators email address.

    */

   public String getSysAdminEmail() {

     return "nobody@nobody.com";

   }

   /**

    * Set up the (@link PoemContext}, but only the Method.

    * 

    * @param melati

    *          the current {@link Melati}

    * @return a partially configured {@link PoemContext}

    */

   protected PoemContext poemContext(Melati melati) {

     PoemContext it = new PoemContext();

     String[] arguments = melati.getArguments();

     if (arguments.length > 0)

       it.setMethod(arguments[arguments.length - 1]);

     return it;

   }

   protected String[] applyNamedArguments(String[] arguments) {

     String[] unnamedArguments = new String[] {};

     boolean nextIsOutput = false;

     for (int i = 0; i < arguments.length; i++) {

       if (arguments[i].startsWith("-o"))

         nextIsOutput = true;

       else if (nextIsOutput) {

         setOutput(arguments[i]);

         nextIsOutput = false;

       } else {

         unnamedArguments = (String[])ArrayUtils.added(unnamedArguments,

                 arguments[i]);

       }

     }

     return unnamedArguments;

   }

   public void setOutput(String path) {

     File outputFile;

     try {

       outputFile = new File(path).getCanonicalFile();

     } catch (IOException e) {

       throw new MelatiIOException(e);

     }

     File parent = new File(outputFile.getParent());

     parent.mkdirs();

     try {

       outputFile.createNewFile();

     } catch (IOException e) {

       throw new MelatiIOException(

           "Could not create " + outputFile.getAbsolutePath(), e);

     }

     try {

       setOutput(new PrintStream(new FileOutputStream(outputFile)));

     } catch (FileNotFoundException e) {

       throw new MelatiIOException(e);

     }

   }

   /**

    * {@inheritDoc}

    * 

    * @see org.melati.app.App#setOutput(java.io.PrintStream)

    */

   public void setOutput(PrintStream out) {

     output = out;

   }

   /**

    * Instantiate this method to build up your own output.

    * 

    * @param melati

    *          a configured {@link Melati}

    * @throws Exception

    *           if anything goes wrong

    */

   protected abstract void doConfiguredRequest(final Melati melati)

           throws Exception;

 }