package org.apache.maven.index.reader;
   
   /*
    * 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.
   */
  
  import org.apache.maven.index.reader.Record.EntryKey;
  import org.apache.maven.index.reader.Record.Type;
  import org.apache.maven.index.reader.ResourceHandler.Resource;
  import org.apache.maven.index.reader.WritableResourceHandler.WritableResource;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.text.DateFormat;
  import java.text.SimpleDateFormat;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.Properties;
  import java.util.TimeZone;
  import java.util.regex.Pattern;
  
  /**
   * Reusable code snippets and constants.
   *
   * @since 5.1.2
   */
  public final class Utils
  {
      private Utils()
      {
          // nothing
      }
  
      public static final String INDEX_FILE_PREFIX = "nexus-maven-repository-index";
  
      public static final DateFormat INDEX_DATE_FORMAT;
  
      static
      {
          INDEX_DATE_FORMAT = new SimpleDateFormat( "yyyyMMddHHmmss.SSS Z" );
          INDEX_DATE_FORMAT.setTimeZone( TimeZone.getTimeZone( "GMT" ) );
      }
  
      public static final String FIELD_SEPARATOR = "|";
  
      public static final String NOT_AVAILABLE = "NA";
  
      public static final String UINFO = "u";
  
      public static final String INFO = "i";
  
      public static final Pattern FS_PATTERN = Pattern.compile( Pattern.quote( FIELD_SEPARATOR ) );
  
      /**
       * Creates and loads {@link Properties} from provided {@link Resource} if exists, and closes the resource. If not
       * exists, returns {@code null}.
       */
      public static Properties loadProperties( final Resource resource )
          throws IOException
      {
          try ( InputStream inputStream = resource.read() )
          {
              if ( inputStream == null )
              {
                  return null;
              }
              final Properties properties = new Properties();
              properties.load( inputStream );
              return properties;
          }
      }
  
      /**
       * Saves {@link Properties} to provided {@link WritableResource} and closes the resource.
       */
      public static void storeProperties( final WritableResource writableResource, final Properties properties )
          throws IOException
      {
          try ( writableResource )
          {
              try ( OutputStream outputStream = writableResource.write() )
              {
                  properties.store( outputStream, "Maven Indexer Writer" );
             }
         }
     }
 
     /**
      * Creates a record of type {@link Type#DESCRIPTOR}.
      */
     public static Record descriptor( final String repoId )
     {
         HashMap<EntryKey, Object> entries = new HashMap<>();
         entries.put( Record.REPOSITORY_ID, repoId );
         return new Record( Type.DESCRIPTOR, entries );
     }
 
     /**
      * Creates a record of type {@link Type#ALL_GROUPS}.
      */
     public static Record allGroups( final Collection<String> allGroups )
     {
         HashMap<EntryKey, Object> entries = new HashMap<>();
         entries.put( Record.ALL_GROUPS, allGroups.toArray( new String[0] ) );
         return new Record( Type.ALL_GROUPS, entries );
     }
 
     /**
      * Creates a record of type {@link Type#ROOT_GROUPS}.
      */
     public static Record rootGroups( final Collection<String> rootGroups )
     {
         HashMap<EntryKey, Object> entries = new HashMap<>();
         entries.put( Record.ROOT_GROUPS, rootGroups.toArray( new String[0] ) );
         return new Record( Type.ROOT_GROUPS, entries );
     }
 
     /**
      * Helper to translate the "NA" (not available) input into {@code null} value.
      */
     public static String renvl( final String v )
     {
         return NOT_AVAILABLE.equals( v ) ? null : v;
     }
 
     /**
      * Helper to translate {@code null} into "NA" (not available) value.
      */
     public static String nvl( final String v )
     {
         return v == null ? NOT_AVAILABLE : v;
     }
 
     /**
      * Returns the "root group" of given groupId.
      */
     public static String rootGroup( final String groupId )
     {
         int n = groupId.indexOf( '.' );
         if ( n > -1 )
         {
             return groupId.substring( 0, n );
         }
         return groupId;
     }
 }