package org.apache.velocity.runtime.resource.loader.adapter;

/*
 * The Apache Software License, Version 1.1
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 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
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 * ====================================================================
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import org.apache.velocity.runtime.resource.loader.ResourceLoader;
import org.apache.velocity.runtime.resource.loader.ResourceLoaderFactory;
import org.apache.velocity.runtime.resource.Resource;
import org.apache.velocity.exception.ResourceNotFoundException;

import java.util.Hashtable;
import java.util.Map;
import java.util.List;
import java.io.InputStream;

import org.apache.commons.collections.ExtendedProperties;


/**
 *  Simple ResourceLoader adapter derived from Dan Rall's proposed
 *  changes to the ClasspathResourceLoader
 *
 * @author <a href="geirm@apache.org">Geir Magnusson Jr.</a>
 * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
 * @version $Id:$
 */
public class PathMapAdapter extends ResourceLoader
{
    /**
     *   The paths to search for templates.
     */
    protected List paths = null;

    /**
     *   Template to path mappings
     */
    protected Map templatePaths = new Hashtable();

    /**
     *  Resource loader we are going to use.  We need to have
     *  one specified?
     */
    protected ResourceLoader resourceLoader = null;

    /**
      *  This is abstract in the base class, so we need it
      */
    public void init( ExtendedProperties configuration)
    {
        rsvc.info("PathMapAdapter : initialization starting.");

        /*
         * the most important thing is that we are are given
         * a ResourceLoader to use
         */

        String loaderClass = configuration.getString( "loader" );

        try
        {
             ExtendedProperties loaderConfiguration =
                configuration.subset("loader");

            resourceLoader = ResourceLoaderFactory.getLoader( rsvc, loaderClass);
            resourceLoader.commonInit( rsvc, loaderConfiguration);
            resourceLoader.init( loaderConfiguration);

            rsvc.info("PathMapAdapter : using loader : " + loaderClass );
        }
        catch( Exception e )
        {
            rsvc.error("PathMapAdapter : problem instantiating loader : " + e );
        }

        /*
         *  now get the paths
         */
        paths = configuration.getVector("path");

        int size = paths.size();

        for (int i = 0; i < size; i++)
        {
            rsvc.info("PathMapAdapter : adding path '" +
                      paths.get(i) + "'");
        }
        rsvc.info("PathMapAdapter : initialization complete.");
    }


    /**
      * Get an InputStream so that the Runtime can build a
      * template with it.
      *
      * @param name name of template to get
      * @return InputStream containing the template
      * @throws ResourceNotFoundException if template not found
      *         in  classpath.
      */
     public synchronized InputStream getResourceStream(String name)
         throws ResourceNotFoundException
     {
         if (name == null || name.length() == 0)
         {
             throw new ResourceNotFoundException("No template name provided");
         }

         InputStream result = null;
         String path = (String) templatePaths.get(name);

         if (path != null)
         {
             try
             {
                 result = openStream( path, name);
             }
             catch (Exception e)
             {
                 throw new ResourceNotFoundException("Couldn't find resource: " +
                                                     e.getMessage());
             }
         }
         else
         {
             int size = paths.size();
             for (int i = 0; i < size; i++)
             {
                 path = (String) paths.get(i);
                 try
                 {
                     rsvc.debug("Looking for " + name + " in path " + path);
                     path = normalizePath(path);
                     rsvc.debug("Normalized path to " + path);
                     result = openStream( path, name);
                     if (result != null)
                     {
                         templatePaths.put(name, path);
                         break;
                     }
                 }
                 catch (Exception ignored)
                 {
                     // Expected to happen for resources not found in
                     // this path.
                 }
             }
         }

         if ( result == null)
         {
            throw new ResourceNotFoundException("PathMapAdapter : " + name + " not found");
         }

         return result;
     }

     /**
      *  Uses the configured loader to return the stream
      */
     private InputStream openStream( String path, String name)
        throws Exception
     {
         return resourceLoader.getResourceStream(
                 path.length() > 0 ? path + "/" + name : name );
     }

     /**
      * Normalizes a path for use with a <code>ClassLoader</code>.
      */
     private String normalizePath(String path)
     {
         if (path.startsWith("/"))
         {
             path = path.substring(1);
         }
         else if (path.startsWith("./"))
         {
             path = path.substring(2);
         }
         else if (path.equals("."))
         {
             path = "";
         }
         return path;
     }

    public boolean isSourceModified(Resource resource)
    {
        return resourceLoader.isSourceModified( resource );
    }

    public long getLastModified(Resource resource)
    {
        return resourceLoader.getLastModified( resource );
    }
}