/*
    *   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
    *
   *     https://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.directory.api.ldap.schema.extractor.impl;
  
  
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.net.URL;
  import java.nio.charset.StandardCharsets;
  import java.util.Enumeration;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.regex.Pattern;
  import java.util.zip.ZipEntry;
  import java.util.zip.ZipFile;
  
  import org.apache.directory.api.i18n.I18n;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * Lists LDIF resources available from the classpath.
   *
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public final class ResourceMap
  {
      /** the system property which can be used to load schema from a user specified
       *  resource like a absolute path to a directory or jar file.
       *  This is useful to start embedded DirectoryService in a servlet container environment
       *
       *  usage: -Dschema.resource.location=/tmp/schema
       *                OR
       *         -Dschema.resource.location=/tmp/api-ldap-schema-1.0.0-M13.jar
       *  */
      private static final String SCHEMA_RESOURCE_LOCATION = "schema.resource.location";
  
      /** The logger. */
      private static final Logger LOG = LoggerFactory.getLogger( ResourceMap.class );
  
  
      /**
       * Private constructor.
       */
      private ResourceMap()
      {
      }
  
  
      /**
       * For all elements of java.class.path OR from the resource name set in the
       * system property 'schema.resource.location' get a Map of resources
       * Pattern pattern = Pattern.compile(".*").
       * The keys represent resource names and the boolean parameter indicates
       * whether or not the resource is in a Jar file.
       *
       * @param pattern the pattern to match
       * @return the resources with markers - true if resource is in Jar
       */
      public static Map<String, Boolean> getResources( Pattern pattern )
      {
          HashMap<String, Boolean> retval = new HashMap<>();
  
          String schemaResourceLoc = System.getProperty( SCHEMA_RESOURCE_LOCATION, "" );
  
          if ( schemaResourceLoc.trim().length() > 0 )
          {
              if ( LOG.isDebugEnabled() )
              {
                  LOG.debug( I18n.msg( I18n.MSG_16008_LOADING_FROM_USER_SCHEMA, schemaResourceLoc ) );
              }
  
              File file = new File( schemaResourceLoc );
  
              if ( file.exists() )
              {
                  getResources( retval, schemaResourceLoc, pattern );
              }
             else
             {
                 LOG.error( I18n.err( I18n.ERR_16043_CANOT_LOAD_SCHEMA, schemaResourceLoc ) );
             }
         }
         else
         {
             getResourcesFromClassloader( retval, pattern );
         }
 
         return retval;
     }
 
 
     private static void getResources( HashMap<String, Boolean> map,
         String element, Pattern pattern )
     {
         File file = new File( element );
 
         if ( !file.exists() )
         {
             // this may happen if the class path contains an element that doesn't exist
             if ( LOG.isDebugEnabled() )
             {
                 LOG.debug( I18n.msg( I18n.MSG_16009_ELEMENT_DOES_NOT_EXIST, element ) );
             }
 
             return;
         }
 
         if ( file.isDirectory() )
         {
             getResourcesFromDirectory( map, file, pattern );
         }
         else
         {
             getResourcesFromJarFile( map, file, pattern );
         }
     }
 
 
     private static void getResourcesFromJarFile( HashMap<String, Boolean> map,
         File file, Pattern pattern )
     {
         ZipFile zf;
 
         try
         {
             zf = new ZipFile( file );
         }
         catch ( IOException e )
         {
             throw new Error( e );
         }
 
         Enumeration<? extends ZipEntry> e = zf.entries();
 
         while ( e.hasMoreElements() )
         {
             ZipEntry ze = e.nextElement();
             String fileName = ze.getName();
             boolean accept = pattern.matcher( fileName ).matches();
 
             if ( accept )
             {
                 map.put( fileName, Boolean.TRUE );
             }
         }
         try
         {
             zf.close();
         }
         catch ( IOException e1 )
         {
             throw new Error( e1 );
         }
     }
 
 
     private static void getResourcesFromDirectory(
         HashMap<String, Boolean> map, File directory, Pattern pattern )
     {
         File[] fileList = directory.listFiles();
 
         if ( fileList != null )
         {
             for ( File file : fileList )
             {
                 if ( file.isDirectory() )
                 {
                     getResourcesFromDirectory( map, file, pattern );
                 }
                 else
                 {
                     try
                     {
                         String fileName = file.getCanonicalPath();
                         boolean accept = pattern.matcher( fileName ).matches();
     
                         if ( accept )
                         {
                             map.put( fileName, Boolean.FALSE );
                         }
                     }
                     catch ( IOException e )
                     {
                         LOG.error( I18n.err( I18n.ERR_16044_CANNOT_LOAD_FILE, file.getAbsolutePath(), e.getMessage() ) );
     
                         // Continue...
                     }
                 }
             }
         }
     }
 
 
     private static void getResourcesFromClassloader( HashMap<String, Boolean> map, Pattern pattern )
     {
         try
         {
             ClassLoader cl = ResourceMap.class.getClassLoader();
             Enumeration<URL> indexes = cl.getResources( "META-INF/apacheds-schema.index" );
 
             while ( indexes.hasMoreElements() )
             {
                 URL index = null;
 
                 try
                 {
                     index = indexes.nextElement();
                     
                     try ( InputStream in = index.openStream() )
                     {
                         try ( BufferedReader reader = new BufferedReader( new InputStreamReader( in, StandardCharsets.UTF_8 ) ) )
                         {
                             String line = reader.readLine();
             
                             while ( line != null )
                             {
                                 boolean accept = pattern.matcher( line ).matches();
             
                                 if ( accept )
                                 {
                                     map.put( line, Boolean.TRUE );
                                 }
             
                                 line = reader.readLine();
                             }
                         }        
                     }
                 }
                 catch ( IOException ioe )
                 {
                     LOG.error( I18n.err( I18n.ERR_16047_CANNOT_LOAD_RESOURCE, index, ioe.getMessage() ) );
                     // Continue...
                 }
             }
         }
         catch ( IOException e )
         {
             LOG.error( I18n.err( I18n.ERR_16045_ERROR_LOADING_RESOURCE, e.getMessage() ) );
             throw new Error( e );
         }
     }
 }