//
   //  ========================================================================
   //  Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.util.resource;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.nio.channels.ReadableByteChannel;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.HashSet;
  import java.util.List;
  import java.util.StringTokenizer;
  
  import org.eclipse.jetty.util.URIUtil;
  
  /**
   * A collection of resources (dirs).
   * Allows webapps to have multiple (static) sources.
   * The first resource in the collection is the main resource.
   * If a resource is not found in the main resource, it looks it up in 
   * the order the resources were constructed.
   * 
   * 
   *
   */
  public class ResourceCollection extends Resource
  {
      private Resource[] _resources;
  
      /* ------------------------------------------------------------ */
      /**
       * Instantiates an empty resource collection.
       * 
       * This constructor is used when configuring jetty-maven-plugin.
       */
      public ResourceCollection()
      {
          _resources = new Resource[0];
      }
      
      /* ------------------------------------------------------------ */
      /**
       * Instantiates a new resource collection.
       *
       * @param resources the resources to be added to collection
       */
      public ResourceCollection(Resource... resources)
      {
          List<Resource> list = new ArrayList<Resource>();
          for (Resource r : resources)
          {
              if (r==null)
                  continue;
              if (r instanceof ResourceCollection)
              {
                  for (Resource r2 : ((ResourceCollection)r).getResources())
                      list.add(r2);
              }
              else
                  list.add(r);
          }
          _resources = list.toArray(new Resource[list.size()]);
          for(Resource r : _resources)
          {
              if(!r.exists() || !r.isDirectory())
                  throw new IllegalArgumentException(r + " is not an existing directory.");
          }
      }
      
      
      /* ------------------------------------------------------------ */
      /**
       * Instantiates a new resource collection.
       *
       * @param resources the resource strings to be added to collection
       */
      public ResourceCollection(String[] resources)
      {
          _resources = new Resource[resources.length];
         try
         {
             for(int i=0; i<resources.length; i++)
             {
                 _resources[i] = Resource.newResource(resources[i]);
                 if(!_resources[i].exists() || !_resources[i].isDirectory())
                     throw new IllegalArgumentException(_resources[i] + " is not an existing directory.");
             }
         }
         catch(IllegalArgumentException e)
         {
             throw e;
         }
         catch(Exception e)
         {
             throw new RuntimeException(e);
         }
     }
     
     /* ------------------------------------------------------------ */
     /**
      * Instantiates a new resource collection.
      *
      * @param csvResources the string containing comma-separated resource strings
      */
     public ResourceCollection(String csvResources)
     {
         setResourcesAsCSV(csvResources);
     }
     
     /* ------------------------------------------------------------ */
     /**
      * Retrieves the resource collection's resources.
      * 
      * @return the resource array
      */
     public Resource[] getResources()
     {
         return _resources;
     }
     
     /* ------------------------------------------------------------ */
     /**
      * Sets the resource collection's resources.
      *
      * @param resources the new resource array
      */
     public void setResources(Resource[] resources)
     {
         _resources = resources != null ? resources : new Resource[0];
     }
 
     /* ------------------------------------------------------------ */
     /**
      * Sets the resources as string of comma-separated values.
      * This method should be used when configuring jetty-maven-plugin.
      *
      * @param csvResources the comma-separated string containing
      *                     one or more resource strings.
      */
     public void setResourcesAsCSV(String csvResources)
     {
         StringTokenizer tokenizer = new StringTokenizer(csvResources, ",;");
         int len = tokenizer.countTokens();
         if(len==0)
         {
             throw new IllegalArgumentException("ResourceCollection@setResourcesAsCSV(String) " +
                     " argument must be a string containing one or more comma-separated resource strings.");
         }
         
         _resources = new Resource[len];
         try
         {            
             for(int i=0; tokenizer.hasMoreTokens(); i++)
             {
                 _resources[i] = Resource.newResource(tokenizer.nextToken().trim());
                 if(!_resources[i].exists() || !_resources[i].isDirectory())
                     throw new IllegalArgumentException(_resources[i] + " is not an existing directory.");
             }
         }
         catch(Exception e)
         {
             throw new RuntimeException(e);
         }
     }
     
     /* ------------------------------------------------------------ */
     /**
      * @param path The path segment to add
      * @return The contained resource (found first) in the collection of resources
      */
     @Override
     public Resource addPath(String path) throws IOException, MalformedURLException
     {
         if(_resources==null)
             throw new IllegalStateException("*resources* not set.");
         
         if(path==null)
             throw new MalformedURLException();
         
         if(path.length()==0 || URIUtil.SLASH.equals(path))
             return this;
         
         Resource resource=null;
         ArrayList<Resource> resources = null;
         int i=0;
         for(; i<_resources.length; i++)
         {
             resource = _resources[i].addPath(path);  
             if (resource.exists())
             {
                 if (resource.isDirectory())
                     break;       
                 return resource;
             }
         }  
 
         for(i++; i<_resources.length; i++)
         {
             Resource r = _resources[i].addPath(path); 
             if (r.exists() && r.isDirectory())
             {
                 if (resource!=null)
                 {
                     resources = new ArrayList<Resource>();
                     resources.add(resource);
                     resource=null;
                 }
                 resources.add(r);
             }
         }
 
         if (resource!=null)
             return resource;
         if (resources!=null)
             return new ResourceCollection(resources.toArray(new Resource[resources.size()]));
         return null;
     }
     
     /* ------------------------------------------------------------ */
     /**
      * @param path
      * @return the resource(file) if found, returns a list of resource dirs if its a dir, else null.
      * @throws IOException
      * @throws MalformedURLException
      */
     protected Object findResource(String path) throws IOException, MalformedURLException
     {        
         Resource resource=null;
         ArrayList<Resource> resources = null;
         int i=0;
         for(; i<_resources.length; i++)
         {
             resource = _resources[i].addPath(path);  
             if (resource.exists())
             {
                 if (resource.isDirectory())
                     break;
                
                 return resource;
             }
         }  
 
         for(i++; i<_resources.length; i++)
         {
             Resource r = _resources[i].addPath(path); 
             if (r.exists() && r.isDirectory())
             {
                 if (resource!=null)
                 {
                     resources = new ArrayList<Resource>();
                     resources.add(resource);
                 }
                 resources.add(r);
             }
         }
         
         if (resource!=null)
             return resource;
         if (resources!=null)
             return resources;
         return null;
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public boolean delete() throws SecurityException
     {
         throw new UnsupportedOperationException();
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public boolean exists()
     {
         if(_resources==null)
             throw new IllegalStateException("*resources* not set.");
         
         return true;
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public File getFile() throws IOException
     {
         if(_resources==null)
             throw new IllegalStateException("*resources* not set.");
         
         for(Resource r : _resources)
         {
             File f = r.getFile();
             if(f!=null)
                 return f;
         }
         return null;
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public InputStream getInputStream() throws IOException
     {
         if(_resources==null)
             throw new IllegalStateException("*resources* not set.");
         
         for(Resource r : _resources)
         {
             InputStream is = r.getInputStream();
             if(is!=null)
                 return is;
         }
         return null;
     }
 
     /* ------------------------------------------------------------ */
     @Override 
     public ReadableByteChannel getReadableByteChannel() throws IOException
     {
         if(_resources==null)
             throw new IllegalStateException("*resources* not set.");
         
         for(Resource r : _resources)
         {
             ReadableByteChannel channel = r.getReadableByteChannel();
             if(channel!=null)
                 return channel;
         }
         return null;
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public String getName()
     {
         if(_resources==null)
             throw new IllegalStateException("*resources* not set.");
         
         for(Resource r : _resources)
         {
             String name = r.getName();
             if(name!=null)
                 return name;
         }
         return null;
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public OutputStream getOutputStream() throws IOException, SecurityException
     {
         if(_resources==null)
             throw new IllegalStateException("*resources* not set.");
         
         for(Resource r : _resources)
         {
             OutputStream os = r.getOutputStream();
             if(os!=null)
                 return os;
         }
         return null;
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public URL getURL()
     {
         if(_resources==null)
             throw new IllegalStateException("*resources* not set.");
         
         for(Resource r : _resources)
         {
             URL url = r.getURL();
             if(url!=null)
                 return url;
         }
         return null;
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public boolean isDirectory()
     {
         if(_resources==null)
             throw new IllegalStateException("*resources* not set.");
         
         return true;
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public long lastModified()
     {
         if(_resources==null)
             throw new IllegalStateException("*resources* not set.");
         
         for(Resource r : _resources)
         {
             long lm = r.lastModified();
             if (lm!=-1)
                 return lm;
         }
         return -1;
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public long length()
     {
         return -1;
     }    
     
     /* ------------------------------------------------------------ */
     /**
      * @return The list of resource names(merged) contained in the collection of resources.
      */    
     @Override
     public String[] list()
     {
         if(_resources==null)
             throw new IllegalStateException("*resources* not set.");
         
         HashSet<String> set = new HashSet<String>();
         for(Resource r : _resources)
         {
             for(String s : r.list())
                 set.add(s);
         }
         String[] result=set.toArray(new String[set.size()]);
         Arrays.sort(result);
         return result;
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public void release()
     {
         if(_resources==null)
             throw new IllegalStateException("*resources* not set.");
         
         for(Resource r : _resources)
             r.release();
     }
     
     /* ------------------------------------------------------------ */
     @Override
     public boolean renameTo(Resource dest) throws SecurityException
     {
         throw new UnsupportedOperationException();
     }
 
     /* ------------------------------------------------------------ */
     @Override
     public void copyTo(File destination)
         throws IOException
     {
         for (int r=_resources.length;r-->0;)
             _resources[r].copyTo(destination);
     }
     
     /* ------------------------------------------------------------ */
     /**
      * @return the list of resources separated by a path separator
      */
     @Override
     public String toString()
     {
         if(_resources==null)
             return "[]";
         
         return String.valueOf(Arrays.asList(_resources));
     }
 
     /* ------------------------------------------------------------ */
     @Override
     public boolean isContainedIn(Resource r) throws MalformedURLException
     {
         // TODO could look at implementing the semantic of is this collection a subset of the Resource r?
         return false;
     }
 
 }