/*
    * 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
    *
    *      https://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.io;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.io.File;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.commons.lang3.ArrayUtils;
  import org.apache.commons.lang3.SystemProperties;
  import org.junit.jupiter.api.Test;
  import org.junit.jupiter.api.io.TempDir;
  
  /**
   * Test cases for FileUtils.cleanDirectory() method that involve symlinks.
   * & FileUtils.isSymlink(File file)
   */
  class FileUtilsCleanSymlinksTest {
  
      @TempDir
      public File top;
  
      private boolean setupSymlink(final File res, final File link) throws Exception {
          // create symlink
          final List<String> args = new ArrayList<>();
          args.add("ln");
          args.add("-s");
  
          args.add(res.getAbsolutePath());
          args.add(link.getAbsolutePath());
  
          final Process proc;
  
          proc = Runtime.getRuntime().exec(args.toArray(ArrayUtils.EMPTY_STRING_ARRAY));
          return proc.waitFor() == 0;
      }
  
      @Test
      void testCleanDirWithASymlinkDir() throws Exception {
          if (SystemProperties.getOsName().startsWith("Win")) {
              // Can't use "ln" for symlinks on the command line in Windows.
              return;
          }
  
          final File realOuter = new File(top, "realouter");
          assertTrue(realOuter.mkdirs());
  
          final File realInner = new File(realOuter, "realinner");
          assertTrue(realInner.mkdirs());
  
          FileUtils.touch(new File(realInner, "file1"));
          assertEquals(1, realInner.list().length);
  
          final File randomDirectory = new File(top, "randomDir");
          assertTrue(randomDirectory.mkdirs());
  
          FileUtils.touch(new File(randomDirectory, "randomfile"));
          assertEquals(1, randomDirectory.list().length);
  
          final File symlinkDirectory = new File(realOuter, "fakeinner");
          assertTrue(setupSymlink(randomDirectory, symlinkDirectory));
  
          assertEquals(1, symlinkDirectory.list().length);
  
          // assert contents of the real directory were removed including the symlink
          FileUtils.cleanDirectory(realOuter);
          assertTrue(realOuter.exists());
          assertEquals(0, realOuter.list().length);
  
          // ensure that the contents of the symlink were NOT removed.
          assertEquals(1, randomDirectory.list().length, "Contents of symbolic link should not have been removed");
      }
  
      @Test
      void testCleanDirWithParentSymlinks() throws Exception {
          if (SystemProperties.getOsName().startsWith("Win")) {
              // Can't use "ln" for symlinks on the command line in Windows.
              return;
          }
  
          final File realParent = new File(top, "realparent");
         assertTrue(realParent.mkdirs());
 
         final File realInner = new File(realParent, "realinner");
         assertTrue(realInner.mkdirs());
 
         FileUtils.touch(new File(realInner, "file1"));
         assertEquals(1, realInner.list().length);
 
         final File randomDirectory = new File(top, "randomDir");
         assertTrue(randomDirectory.mkdirs());
 
         FileUtils.touch(new File(randomDirectory, "randomfile"));
         assertEquals(1, randomDirectory.list().length);
 
         final File symlinkDirectory = new File(realParent, "fakeinner");
         assertTrue(setupSymlink(randomDirectory, symlinkDirectory));
 
         assertEquals(1, symlinkDirectory.list().length);
 
         final File symlinkParentDirectory = new File(top, "fakeouter");
         assertTrue(setupSymlink(realParent, symlinkParentDirectory));
 
         // assert contents of the real directory were removed including the symlink
         // should clean the contents of this but not recurse into other links
         FileUtils.cleanDirectory(symlinkParentDirectory);
         assertTrue(symlinkParentDirectory.exists());
         assertEquals(0, symlinkParentDirectory.list().length);
         assertEquals(0, realParent.list().length);
 
         // ensure that the contents of the symlink were NOT removed.
         assertEquals(1, randomDirectory.list().length, "Contents of symbolic link should not have been removed");
     }
 
     @Test
     void testCleanDirWithSymlinkFile() throws Exception {
         if (SystemProperties.getOsName().startsWith("Win")) {
             // Can't use "ln" for symlinks on the command line in Windows.
             return;
         }
 
         final File realOuter = new File(top, "realouter");
         assertTrue(realOuter.mkdirs());
 
         final File realInner = new File(realOuter, "realinner");
         assertTrue(realInner.mkdirs());
 
         final File realFile = new File(realInner, "file1");
         FileUtils.touch(realFile);
         assertEquals(1, realInner.list().length);
 
         final File randomFile = new File(top, "randomfile");
         FileUtils.touch(randomFile);
 
         final File symlinkFile = new File(realInner, "fakeinner");
         assertTrue(setupSymlink(randomFile, symlinkFile));
 
         assertEquals(2, realInner.list().length);
 
         // assert contents of the real directory were removed including the symlink
         FileUtils.cleanDirectory(realOuter);
         assertTrue(realOuter.exists());
         assertEquals(0, realOuter.list().length);
 
         // ensure that the contents of the symlink were NOT removed.
         assertTrue(randomFile.exists());
         assertFalse(symlinkFile.exists());
     }
 
     @Test
     void testCorrectlyIdentifySymlinkWithParentSymLink() throws Exception {
         if (SystemProperties.getOsName().startsWith("Win")) {
             // Can't use "ln" for symlinks on the command line in Windows.
             return;
         }
 
         final File realParent = new File(top, "realparent");
         assertTrue(realParent.mkdirs());
 
         final File symlinkParentDirectory = new File(top, "fakeparent");
         assertTrue(setupSymlink(realParent, symlinkParentDirectory));
 
         final File realChild = new File(symlinkParentDirectory, "realChild");
         assertTrue(realChild.mkdirs());
 
         final File symlinkChild = new File(symlinkParentDirectory, "fakeChild");
         assertTrue(setupSymlink(realChild, symlinkChild));
 
         assertTrue(FileUtils.isSymlink(symlinkChild));
         assertFalse(FileUtils.isSymlink(realChild));
     }
 
     @Test
     void testIdentifiesBrokenSymlinkFile() throws Exception {
         if (SystemProperties.getOsName().startsWith("Win")) {
             // Can't use "ln" for symlinks on the command line in Windows.
             return;
         }
 
         final File nonExistentFile = new File(top, "non-existent");
         final File symlinkFile = new File(top, "fakeinner");
         final File badSymlinkInPathFile = new File(symlinkFile, "fakeinner");
         final File nonExistentParentFile = new File("non-existent", "file");
 
         assertTrue(setupSymlink(nonExistentFile, symlinkFile));
 
         assertTrue(FileUtils.isSymlink(symlinkFile));
         assertFalse(FileUtils.isSymlink(nonExistentFile));
         assertFalse(FileUtils.isSymlink(nonExistentParentFile));
         assertFalse(FileUtils.isSymlink(badSymlinkInPathFile));
     }
 
     @Test
     void testIdentifiesSymlinkDir() throws Exception {
         if (SystemProperties.getOsName().startsWith("Win")) {
             // Can't use "ln" for symlinks on the command line in Windows.
             return;
         }
 
         final File randomDirectory = new File(top, "randomDir");
         assertTrue(randomDirectory.mkdirs());
 
         final File symlinkDirectory = new File(top, "fakeDir");
         assertTrue(setupSymlink(randomDirectory, symlinkDirectory));
 
         assertTrue(FileUtils.isSymlink(symlinkDirectory));
         assertFalse(FileUtils.isSymlink(randomDirectory));
     }
 
     @Test
     void testIdentifiesSymlinkFile() throws Exception {
         if (SystemProperties.getOsName().startsWith("Win")) {
             // Can't use "ln" for symlinks on the command line in Windows.
             return;
         }
 
         final File randomFile = new File(top, "randomfile");
         FileUtils.touch(randomFile);
 
         final File symlinkFile = new File(top, "fakeinner");
         assertTrue(setupSymlink(randomFile, symlinkFile));
 
         assertTrue(FileUtils.isSymlink(symlinkFile));
         assertFalse(FileUtils.isSymlink(randomFile));
     }
 
     @Test
     void testStillClearsIfGivenDirectoryIsASymlink() throws Exception {
         if (SystemProperties.getOsName().startsWith("Win")) {
             // Can't use "ln" for symlinks on the command line in Windows.
             return;
         }
 
         final File randomDirectory = new File(top, "randomDir");
         assertTrue(randomDirectory.mkdirs());
 
         FileUtils.touch(new File(randomDirectory, "randomfile"));
         assertEquals(1, randomDirectory.list().length);
 
         final File symlinkDirectory = new File(top, "fakeDir");
         assertTrue(setupSymlink(randomDirectory, symlinkDirectory));
 
         FileUtils.cleanDirectory(symlinkDirectory);
         assertTrue(symlinkDirectory.exists());
         assertEquals(0, symlinkDirectory.list().length);
         assertEquals(0, randomDirectory.list().length);
     }
 
 }