/*
    * 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.maven.index.reader;
  
  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;
  
  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;
  
  /**
   * 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;
     }
 }