/*
    *  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.loader;
  
  
  import java.io.File;
  import java.io.FileNotFoundException;
  import java.io.FilenameFilter;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.directory.api.i18n.I18n;
  import org.apache.directory.api.ldap.model.constants.SchemaConstants;
  import org.apache.directory.api.ldap.model.entry.Entry;
  import org.apache.directory.api.ldap.model.exception.LdapException;
  import org.apache.directory.api.ldap.model.ldif.LdifEntry;
  import org.apache.directory.api.ldap.model.ldif.LdifReader;
  import org.apache.directory.api.ldap.model.schema.registries.AbstractSchemaLoader;
  import org.apache.directory.api.ldap.model.schema.registries.Schema;
  import org.apache.directory.api.util.Strings;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * Loads schema data from LDIF files containing entries representing schema
   * objects, using the meta schema format.
   *
   * This class is used only for tests.
   * 
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class LdifSchemaLoader extends AbstractSchemaLoader
  {
      /** ldif file extension used */
      private static final String LDIF_EXT = "ldif";
  
      /** ou=schema LDIF file name */
      private static final String OU_SCHEMA_LDIF = "ou=schema." + LDIF_EXT;
  
      /** static class logger */
      private static final Logger LOG = LoggerFactory.getLogger( LdifSchemaLoader.class );
  
      /** directory containing the schema LDIF file for ou=schema */
      private final File baseDirectory;
  
      /** a filter for listing all the LDIF files within a directory */
      private final FilenameFilter ldifFilter = new FilenameFilter()
      {
          @Override
          public boolean accept( File file, String name )
          {
              return name.endsWith( LDIF_EXT );
          }
      };
  
  
      /**
       * Creates a new LDIF based SchemaLoader. The constructor checks to make
       * sure the supplied base directory exists and contains a schema.ldif file
       * and if not complains about it.
       *
       * @param baseDirectory the schema LDIF base directory
       * @throws LdapException if the base directory does not exist or does not
       * a valid schema.ldif file
       * @throws IOException If we can't load the schema
       */
      public LdifSchemaLoader( File baseDirectory ) throws LdapException, IOException
      {
          this.baseDirectory = baseDirectory;
  
          if ( !baseDirectory.exists() )
          {
              String msg = I18n.err( I18n.ERR_16046_BASE_DIR_DOES_NOT_EXIST, baseDirectory.getAbsolutePath() );
              LOG.error( msg );
              throw new IllegalArgumentException( msg );
          }
  
          File schemaLdif = new File( baseDirectory, OU_SCHEMA_LDIF );
  
          if ( !schemaLdif.exists() )
         {
             String msg = I18n.err( I18n.ERR_16010_NO_SHEMA_FILE, schemaLdif.getAbsolutePath() );
             LOG.error( msg );
             throw new FileNotFoundException( msg );
         }
 
         if ( LOG.isDebugEnabled() )
         {
             LOG.debug( I18n.msg( I18n.MSG_16010_USING_BASE_SCHEMA_DIR, baseDirectory ) );
         }
 
         initializeSchemas();
     }
 
 
     /**
      * Scans for LDIF files just describing the various schema contained in
      * the schema repository.
      *
      * @throws LdapException if the schemas can't be initialized
      * @throws IOException If teh schema can't be read
      */
     private void initializeSchemas() throws LdapException, IOException
     {
         if ( LOG.isDebugEnabled() )
         {
             LOG.debug( I18n.msg( I18n.MSG_16006_INITIALIZING_SCHEMA ) );
         }
 
         File schemaDirectory = new File( baseDirectory, SchemaConstants.OU_SCHEMA );
         String[] ldifFiles = schemaDirectory.list( ldifFilter );
 
         if ( ldifFiles != null )
         {
             for ( String ldifFile : ldifFiles )
             {
                 File file = new File( schemaDirectory, ldifFile );
 
                 try ( LdifReader reader = new LdifReader( file ) )
                 {
                     
                     LdifEntry entry = reader.next();
                     Schema schema = getSchema( entry.getEntry() );
 
                     if ( schema == null )
                     {
                         // The entry was not a schema, skip it
                         continue;
                     }
 
                     schemaMap.put( schema.getSchemaName(), schema );
 
                     if ( LOG.isDebugEnabled() )
                     {
                         LOG.debug( I18n.msg( I18n.MSG_16007_SCHEMA_INITIALIZED, schema ) );
                     }
                 }
                 catch ( LdapException e )
                 {
                     LOG.error( I18n.err( I18n.ERR_16009_LDIF_LOAD_FAIL, ldifFile ), e );
                     throw e;
                 }
             }
         }
     }
 
 
     /**
      * Utility method to get the file for a schema directory.
      *
      * @param schema the schema to get the file for
      * @return the file for the specific schema directory
      */
     private File getSchemaDirectory( Schema schema )
     {
         return new File( new File( baseDirectory, SchemaConstants.OU_SCHEMA ), "cn="
             + Strings.lowerCase( schema.getSchemaName() ) );
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public List<Entry> loadComparators( Schema... schemas ) throws LdapException, IOException
     {
         List<Entry> comparatorList = new ArrayList<>();
 
         if ( schemas == null )
         {
             return comparatorList;
         }
 
         for ( Schema schema : schemas )
         {
             File comparatorsDirectory = new File( getSchemaDirectory( schema ), SchemaConstants.COMPARATORS_PATH );
 
             if ( !comparatorsDirectory.exists() )
             {
                 return comparatorList;
             }
 
             File[] comparators = comparatorsDirectory.listFiles( ldifFilter );
 
             if ( comparators != null )
             {
                 for ( File ldifFile : comparators )
                 {
                     try ( LdifReader reader = new LdifReader( ldifFile ) )
                     {
                         LdifEntry entry = reader.next();
                         comparatorList.add( entry.getEntry() );
                     }
                 }
             }
         }
 
         return comparatorList;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public List<Entry> loadSyntaxCheckers( Schema... schemas ) throws LdapException, IOException
     {
         List<Entry> syntaxCheckerList = new ArrayList<>();
 
         if ( schemas == null )
         {
             return syntaxCheckerList;
         }
 
         for ( Schema schema : schemas )
         {
             File syntaxCheckersDirectory = new File( getSchemaDirectory( schema ), SchemaConstants.SYNTAX_CHECKERS_PATH );
 
             if ( !syntaxCheckersDirectory.exists() )
             {
                 return syntaxCheckerList;
             }
 
             File[] syntaxCheckerFiles = syntaxCheckersDirectory.listFiles( ldifFilter );
 
             if ( syntaxCheckerFiles != null )
             {
                 for ( File ldifFile : syntaxCheckerFiles )
                 {
                     try ( LdifReader reader = new LdifReader( ldifFile ) )
                     {
                         LdifEntry entry = reader.next();
                         syntaxCheckerList.add( entry.getEntry() );
                     }
                 }
             }
         }
 
         return syntaxCheckerList;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public List<Entry> loadNormalizers( Schema... schemas ) throws LdapException, IOException
     {
         List<Entry> normalizerList = new ArrayList<>();
 
         if ( schemas == null )
         {
             return normalizerList;
         }
 
         for ( Schema schema : schemas )
         {
             File normalizersDirectory = new File( getSchemaDirectory( schema ), SchemaConstants.NORMALIZERS_PATH );
 
             if ( !normalizersDirectory.exists() )
             {
                 return normalizerList;
             }
 
             File[] normalizerFiles = normalizersDirectory.listFiles( ldifFilter );
 
             if ( normalizerFiles != null )
             {
                 for ( File ldifFile : normalizerFiles )
                 {
                     try ( LdifReader reader = new LdifReader( ldifFile ) )
                     {
                         LdifEntry entry = reader.next();
                         normalizerList.add( entry.getEntry() );
                     }
                 }
             }
         }
 
         return normalizerList;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public List<Entry> loadMatchingRules( Schema... schemas ) throws LdapException, IOException
     {
         List<Entry> matchingRuleList = new ArrayList<>();
 
         if ( schemas == null )
         {
             return matchingRuleList;
         }
 
         for ( Schema schema : schemas )
         {
             File matchingRulesDirectory = new File( getSchemaDirectory( schema ), SchemaConstants.MATCHING_RULES_PATH );
 
             if ( !matchingRulesDirectory.exists() )
             {
                 return matchingRuleList;
             }
 
             File[] matchingRuleFiles = matchingRulesDirectory.listFiles( ldifFilter );
 
             if ( matchingRuleFiles != null )
             {
                 for ( File ldifFile : matchingRuleFiles )
                 {
                     try ( LdifReader reader = new LdifReader( ldifFile ) )
                     {
                         LdifEntry entry = reader.next();
                         matchingRuleList.add( entry.getEntry() );
                     }
                 }
             }
         }
 
         return matchingRuleList;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public List<Entry> loadSyntaxes( Schema... schemas ) throws LdapException, IOException
     {
         List<Entry> syntaxList = new ArrayList<>();
 
         if ( schemas == null )
         {
             return syntaxList;
         }
 
         for ( Schema schema : schemas )
         {
             File syntaxesDirectory = new File( getSchemaDirectory( schema ), SchemaConstants.SYNTAXES_PATH );
 
             if ( !syntaxesDirectory.exists() )
             {
                 return syntaxList;
             }
 
             File[] syntaxFiles = syntaxesDirectory.listFiles( ldifFilter );
 
             if ( syntaxFiles != null )
             {
                 for ( File ldifFile : syntaxFiles )
                 {
                     try ( LdifReader reader = new LdifReader( ldifFile ) )
                     {
                         LdifEntry entry = reader.next();
                         syntaxList.add( entry.getEntry() );
                     }
                 }
             }
         }
 
         return syntaxList;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public List<Entry> loadAttributeTypes( Schema... schemas ) throws LdapException, IOException
     {
         List<Entry> attributeTypeList = new ArrayList<>();
 
         if ( schemas == null )
         {
             return attributeTypeList;
         }
 
         for ( Schema schema : schemas )
         {
             // check that the attributeTypes directory exists for the schema
             File attributeTypesDirectory = new File( getSchemaDirectory( schema ), SchemaConstants.ATTRIBUTE_TYPES_PATH );
 
             if ( !attributeTypesDirectory.exists() )
             {
                 return attributeTypeList;
             }
 
             // get list of attributeType LDIF schema files in attributeTypes
             File[] attributeTypeFiles = attributeTypesDirectory.listFiles( ldifFilter );
 
             if ( attributeTypeFiles != null )
             {
                 for ( File ldifFile : attributeTypeFiles )
                 {
                     try ( LdifReader reader = new LdifReader( ldifFile ) )
                     {
                         LdifEntry entry = reader.next();
                         attributeTypeList.add( entry.getEntry() );
                     }
                 }
             }
         }
 
         return attributeTypeList;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public List<Entry> loadMatchingRuleUses( Schema... schemas ) throws LdapException, IOException
     {
         List<Entry> matchingRuleUseList = new ArrayList<>();
 
         if ( schemas == null )
         {
             return matchingRuleUseList;
         }
 
         for ( Schema schema : schemas )
         {
             File matchingRuleUsesDirectory = new File( getSchemaDirectory( schema ),
                 SchemaConstants.MATCHING_RULE_USE_PATH );
 
             if ( !matchingRuleUsesDirectory.exists() )
             {
                 return matchingRuleUseList;
             }
 
             File[] matchingRuleUseFiles = matchingRuleUsesDirectory.listFiles( ldifFilter );
 
             if ( matchingRuleUseFiles != null )
             {
                 for ( File ldifFile : matchingRuleUseFiles )
                 {
                     try ( LdifReader reader = new LdifReader( ldifFile ) )
                     {
                         LdifEntry entry = reader.next();
                         matchingRuleUseList.add( entry.getEntry() );
                     }
                 }
             }
         }
 
         return matchingRuleUseList;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public List<Entry> loadNameForms( Schema... schemas ) throws LdapException, IOException
     {
         List<Entry> nameFormList = new ArrayList<>();
 
         if ( schemas == null )
         {
             return nameFormList;
         }
 
         for ( Schema schema : schemas )
         {
             File nameFormsDirectory = new File( getSchemaDirectory( schema ), SchemaConstants.NAME_FORMS_PATH );
 
             if ( !nameFormsDirectory.exists() )
             {
                 return nameFormList;
             }
 
             File[] nameFormFiles = nameFormsDirectory.listFiles( ldifFilter );
 
             if ( nameFormFiles != null )
             {
                 for ( File ldifFile : nameFormFiles )
                 {
                     try ( LdifReader reader = new LdifReader( ldifFile ) )
                     {
                         LdifEntry entry = reader.next();
                         nameFormList.add( entry.getEntry() );
                     }
                 }
             }
         }
 
         return nameFormList;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public List<Entry> loadDitContentRules( Schema... schemas ) throws LdapException, IOException
     {
         List<Entry> ditContentRuleList = new ArrayList<>();
 
         if ( schemas == null )
         {
             return ditContentRuleList;
         }
 
         for ( Schema schema : schemas )
         {
             File ditContentRulesDirectory = new File( getSchemaDirectory( schema ),
                 SchemaConstants.DIT_CONTENT_RULES_PATH );
 
             if ( !ditContentRulesDirectory.exists() )
             {
                 return ditContentRuleList;
             }
 
             File[] ditContentRuleFiles = ditContentRulesDirectory.listFiles( ldifFilter );
 
             if ( ditContentRuleFiles != null )
             {
                 for ( File ldifFile : ditContentRuleFiles )
                 {
                     try ( LdifReader reader = new LdifReader( ldifFile ) )
                     {
                         LdifEntry entry = reader.next();
                         ditContentRuleList.add( entry.getEntry() );
                     }
                 }
             }
         }
 
         return ditContentRuleList;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public List<Entry> loadDitStructureRules( Schema... schemas ) throws LdapException, IOException
     {
         List<Entry> ditStructureRuleList = new ArrayList<>();
 
         if ( schemas == null )
         {
             return ditStructureRuleList;
         }
 
         for ( Schema schema : schemas )
         {
             File ditStructureRulesDirectory = new File( getSchemaDirectory( schema ),
                 SchemaConstants.DIT_STRUCTURE_RULES_PATH );
 
             if ( !ditStructureRulesDirectory.exists() )
             {
                 return ditStructureRuleList;
             }
 
             File[] ditStructureRuleFiles = ditStructureRulesDirectory.listFiles( ldifFilter );
 
             if ( ditStructureRuleFiles != null )
             {
                 for ( File ldifFile : ditStructureRuleFiles )
                 {
                     try ( LdifReader reader = new LdifReader( ldifFile ) )
                     {
                         LdifEntry entry = reader.next();
                         ditStructureRuleList.add( entry.getEntry() );
                     }
                 }
             }
         }
 
         return ditStructureRuleList;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public List<Entry> loadObjectClasses( Schema... schemas ) throws LdapException, IOException
     {
         List<Entry> objectClassList = new ArrayList<>();
 
         if ( schemas == null )
         {
             return objectClassList;
         }
 
         for ( Schema schema : schemas )
         {
             // get objectClasses directory, check if exists, return if not
             File objectClassesDirectory = new File( getSchemaDirectory( schema ), SchemaConstants.OBJECT_CLASSES_PATH );
 
             if ( !objectClassesDirectory.exists() )
             {
                 return objectClassList;
             }
 
             // get list of objectClass LDIF files from directory and load
             File[] objectClassFiles = objectClassesDirectory.listFiles( ldifFilter );
 
             if ( objectClassFiles != null )
             {
                 for ( File ldifFile : objectClassFiles )
                 {
                     try ( LdifReader reader = new LdifReader( ldifFile ) )
                     {
                         LdifEntry entry = reader.next();
                         objectClassList.add( entry.getEntry() );
                     }
                 }
             }
         }
 
         return objectClassList;
     }
 }