/*
    * 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.shared.jar.identification.exposers;
  
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.jar.JarEntry;
  
  import org.apache.maven.shared.jar.JarAnalyzer;
  import org.apache.maven.shared.jar.identification.JarIdentification;
  import org.apache.maven.shared.jar.identification.JarIdentificationExposer;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Exposer that examines a a JAR for files that contain the text <code>version</code> (case-insensitive) and
   * adds the contents as potential version(s).
   */
  @Singleton
  @Named("textFile")
  public class TextFileExposer implements JarIdentificationExposer {
      private final Logger logger = LoggerFactory.getLogger(getClass());
  
      @Override
      public void expose(JarIdentification identification, JarAnalyzer jarAnalyzer) {
          List<String> textFiles = findTextFileVersions(jarAnalyzer);
          for (String ver : textFiles) {
              identification.addVersion(ver);
          }
      }
  
      private List<String> findTextFileVersions(JarAnalyzer jarAnalyzer) {
          List<String> textVersions = new ArrayList<>();
          List<JarEntry> hits = jarAnalyzer.getVersionEntries();
  
          for (JarEntry entry : hits) {
              // skip this entry if it's a class file.
              if (!entry.getName().endsWith(".class")) // $NON-NLS-1$
              {
                  logger.debug("Version Hit: " + entry.getName());
                  try (InputStream is = jarAnalyzer.getEntryInputStream(entry)) {
                      BufferedReader br = new BufferedReader(new InputStreamReader(is));
  
                      String line = br.readLine();
                      // TODO: check for key=value pair.
                      // TODO: maybe even for groupId entries.
  
                      logger.debug(line);
                      if (line != null && !line.isEmpty()) {
                          textVersions.add(line);
                      }
                  } catch (IOException e) {
                      logger.warn("Unable to read line from " + entry.getName(), e);
                  }
              }
          }
          return textVersions;
      }
  }