/*
    * 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.syncope.core.rest.cxf;
  
  import java.io.File;
  import java.lang.management.ManagementFactory;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.net.URLClassLoader;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  import java.util.Objects;
  import java.util.Optional;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  import org.apache.commons.lang3.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.core.env.Environment;
  import org.springframework.util.ClassUtils;
  
  public final class JavaDocUtils {
  
      private static final Logger LOG = LoggerFactory.getLogger(JavaDocUtils.class);
  
      private static URL toURL(final String classPathEntry) {
          try {
              return new File(classPathEntry).toURI().toURL();
          } catch (MalformedURLException e) {
              throw new IllegalArgumentException("URL could not be created from '" + classPathEntry + "'", e);
          }
      }
  
      /**
       * Inspired by org.springframework.boot.devtools.restart.ChangeableUrls#urlsFromClassLoader
       *
       * @param classLoader class loader
       * @return URLs from underlying class loader
       */
      private static URL[] urlsFromClassLoader(final ClassLoader classLoader) {
          if (classLoader instanceof URLClassLoader) {
              return ((URLClassLoader) classLoader).getURLs();
          }
  
          return Stream.of(ManagementFactory.getRuntimeMXBean().getClassPath().
                  split(File.pathSeparator)).
                  map(JavaDocUtils::toURL).toArray(URL[]::new);
      }
  
      public static Optional<URL[]> getJavaDocURLs() {
          URL[] urls = urlsFromClassLoader(ClassUtils.getDefaultClassLoader());
          if (urls == null) {
              LOG.debug("No classpath URLs found");
              return Optional.empty();
          }
  
          List<URL> javaDocURLs = new ArrayList<>();
          for (URL url : urls) {
              LOG.debug("Processing {}", url.toExternalForm());
  
              String filename = StringUtils.substringAfterLast(url.toExternalForm(), "/");
              if (filename.startsWith("syncope-") && filename.endsWith("-javadoc.jar")) {
                  javaDocURLs.add(url);
              }
          }
  
          LOG.debug("JavaDoc Urls found: {}", javaDocURLs);
          return Optional.of(javaDocURLs.toArray(URL[]::new));
      }
  
      public static Optional<String[]> getJavaDocPaths(final Environment env) {
          String[] result = null;
  
          if (env.containsProperty("javadocPaths")) {
              result = Objects.requireNonNull(env.getProperty("javadocPaths")).split(",");
          }
  
          LOG.debug("JavaDoc paths found: {}",
                  result == null ? List.of() : Arrays.stream(result).collect(Collectors.toList()));
          return Optional.ofNullable(result);
      }
  
     private JavaDocUtils() {
         // private constructor for static utility class
     }
 }