/*
    * 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.
   */
  package org.apache.myfaces.shared.resource;
  
  import java.io.InputStream;
  import java.net.URL;
  import java.util.Comparator;
  import java.util.Iterator;
  import javax.faces.application.ResourceVisitOption;
  import javax.faces.context.FacesContext;
  
  /**
   * Base class for resource loaders.  Resource loaders can lookup resources 
   * as URLs from arbitrary locations, including JAR files.
   */
  public abstract class ResourceLoader
  {
      
      public static final String VERSION_INVALID = "INVALID";
      
      private String _prefix;
      
      public ResourceLoader(String prefix)
      {
          _prefix = prefix;
      }
  
      public abstract String getResourceVersion(String path);
  
      /**
       * Return the max available version found (if exists) or
       * return null if no version available. 
       */
      public abstract String getLibraryVersion(String path);
  
      /**
       * Return the max available version found (if exists) or
       * return null if no version available. 
       */
      public abstract URL getResourceURL(ResourceMeta resourceMeta);
  
      public abstract InputStream getResourceInputStream(ResourceMeta resourceMeta);
      
      public abstract ResourceMeta createResourceMeta(String prefix, String libraryName, String libraryVersion,
              String resourceName, String resourceVersion);
  
      public ResourceMeta createResourceMeta(String prefix, String libraryName, 
              String libraryVersion, String resourceName, String resourceVersion, String contractName)
      {
          return createResourceMeta(prefix, libraryName, libraryVersion, resourceName, resourceVersion);
      }
      
      public abstract boolean libraryExists(String libraryName);
      
      public boolean resourceExists(ResourceMeta resourceMeta)
      {
          return (getResourceURL(resourceMeta) != null);
      }
  
      /*
      public URL getResourceURL(String resourceId)
      {
          throw new UnsupportedOperationException(
              "An implementation for getResourceURL(String resourceId) method is required for JSF 2.2");
      }
      
      public boolean resourceIdExists(String resourceId)
      {
          return (getResourceURL(resourceId) != null);
      }*/
      
      public Iterator<String> iterator(FacesContext facesContext, 
              String path, int maxDepth, ResourceVisitOption... options)
      {
          return null;
      }
      
      private Comparator<String> _versionComparator = null;
  
      protected Comparator<String> getVersionComparator()
      {
          if (_versionComparator == null)
          {
             _versionComparator = new VersionComparator();
         }
         return _versionComparator;
     }
 
     protected void setVersionComparator(Comparator<String> versionComparator)
     {
         _versionComparator = versionComparator;
     }
 
     public static class VersionComparator implements Comparator<String>
     {
 
         public int compare(String s1, String s2)
         {
             int n1 = 0;
             int n2 = 0;
             String o1 = s1;
             String o2 = s2;
 
             boolean p1 = true;
             boolean p2 = true;
 
             while (n1 == n2 && (p1 || p2))
             {
                 int i1 = o1.indexOf('_');
                 int i2 = o2.indexOf('_');
                 if (i1 < 0)
                 {
                     if (o1.length() > 0)
                     {
                         p1 = false;
                         n1 = Integer.valueOf(o1);
                         o1 = "";
                     }
                     else
                     {
                         p1 = false;
                         n1 = 0;
                     }
                 }
                 else
                 {
                     n1 = Integer.valueOf(o1.substring(0, i1));
                     o1 = o1.substring(i1 + 1);
                 }
                 if (i2 < 0)
                 {
                     if (o2.length() > 0)
                     {
                         p2 = false;
                         n2 = Integer.valueOf(o2);
                         o2 = "";
                     }
                     else
                     {
                         p2 = false;
                         n2 = 0;
                     }
                 }
                 else
                 {
                     n2 = Integer.valueOf(o2.substring(0, i2));
                     o2 = o2.substring(i2 + 1);
                 }
             }
 
             if (n1 == n2)
             {
                 return s1.length() - s2.length();
             }
             return n1 - n2;
         }
     }
     
     public String getPrefix()
     {
         return _prefix;
     }
 
     public void setPrefix(String prefix)
     {
         _prefix = prefix;
     }
 }