/*
    * 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.commons.net.examples;
  
  import static org.junit.Assert.fail;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.URLDecoder;
  import java.security.CodeSource;
  import java.util.Enumeration;
  import java.util.Properties;
  import java.util.jar.JarEntry;
  import java.util.jar.JarFile;
  
  import org.junit.Test;
  
  public class MainTest {
  
      private static boolean hasMainMethod(String name) {
          name = name.replace(".class", "");
          try {
              final Class<?> clazz = Class.forName(name, false, MainTest.class.getClassLoader());
              clazz.getMethod("main", String[].class);
              return true;
          } catch (final ClassNotFoundException e) {
              System.out.println("Cannot find " + name);
              return false;
          } catch (final NoSuchMethodException e) {
              return false;
          } catch (final SecurityException e) {
              e.printStackTrace();
          }
          return true;
      }
  
      private static void processFileName(String name, final Properties p) {
          name = name.replace(File.separatorChar, '.');
          if (!name.endsWith(".class") || name.contains("$") // subclasses
                  || name.endsWith("examples.Main.class") // the initial class, don't want to add that
                  || !hasMainMethod(name)) {
              return;
          }
          name = name.replace(".class", "");
          final int lastSep = name.lastIndexOf('.');
          final String alias = name.substring(lastSep + 1);
          if (p.containsKey(alias)) {
              System.out.printf("Duplicate alias: %-25s %s %s %n", alias, name, p.getProperty(alias));
          } else {
              p.setProperty(alias, name);
          }
      }
  
      private static void scanForClasses(final int rootLength, final File current, final Properties p) {
          final File[] files = current.listFiles();
          if (files != null) {
              for (final File file : files) {
                  if (file.isDirectory()) {
                      scanForClasses(rootLength, file, p);
                  } else {
                      processFileName(file.getPath().substring(rootLength), p);
                  }
              }
          }
      }
  
      @Test
      public void checkExamplesPropertiesIsComplete() throws Exception {
          final Properties cp = scanClasses();
          final Properties fp = new Properties();
          try (final InputStream inputStream = this.getClass().getResourceAsStream("examples.properties")) {
              fp.load(inputStream);
          }
          @SuppressWarnings("unchecked") // OK
          final Enumeration<String> propertyNames = (Enumeration<String>) cp.propertyNames();
          while (propertyNames.hasMoreElements()) {
              final String c = propertyNames.nextElement();
              final String fv = fp.getProperty(c);
              final String cv = cp.getProperty(c);
              if (fv == null) {
                  System.out.printf("%-25s %s - missing from examples.properties%n", c, cv);
              } else if (!fv.equals(cv)) {
                  System.out.printf("%-25s %s - expected value %s %n", c, fv, cv);
             }
         }
     }
 
     private Properties scanClasses() throws IOException {
         final CodeSource codeSource = Main.class.getProtectionDomain().getCodeSource();
         // ensure special characters are decoded OK by uing the charset
         // Use canonical path to ensure consistency with Windows
         final String sourceFile = new File(URLDecoder.decode(codeSource.getLocation().getFile(), "UTF-8")).getCanonicalPath();
         final Properties p = new Properties();
         if (sourceFile.endsWith(".jar")) {
             try (final JarFile jf = new JarFile(sourceFile)) {
                 final Enumeration<JarEntry> e = jf.entries();
                 while (e.hasMoreElements()) {
                     final JarEntry je = e.nextElement();
                     final String name = je.getName();
                     processFileName(name, p);
                 }
             }
         } else {
             final File examples = new File(sourceFile, "org/apache/commons/net/examples"); // must match top level examples package name
             if (examples.exists()) {
                 // need to add 1 to allow for path separator between root and file
                 scanForClasses(sourceFile.length() + 1, examples, p);
             } else {
                 fail("Could not find examples classes: " + examples.getCanonicalPath());
             }
         }
         return p;
     }
 }