/*
    * 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.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  import static org.junit.jupiter.api.Assertions.fail;
  
  import java.io.File;
  import java.io.FileFilter;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  import org.apache.commons.io.filefilter.FileFilterUtils;
  import org.apache.commons.io.filefilter.IOFileFilter;
  import org.apache.commons.io.filefilter.NameFileFilter;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests {@link DirectoryWalker}.
   */
  class DirectoryWalkerTest {
  
      /**
       * Test DirectoryWalker implementation that finds files in a directory hierarchy
       * applying a file filter.
       */
      static class TestCancelWalker extends DirectoryWalker<File> {
          private final String cancelFileName;
          private final boolean suppressCancel;
  
          TestCancelWalker(final String cancelFileName, final boolean suppressCancel) {
              this.cancelFileName = cancelFileName;
              this.suppressCancel = suppressCancel;
          }
  
          /** Find files. */
          protected List<File> find(final File startDirectory) throws IOException {
              final List<File> results = new ArrayList<>();
              walk(startDirectory, results);
              return results;
          }
  
          /** Handles Cancel. */
          @Override
          protected void handleCancelled(final File startDirectory, final Collection<File> results, final CancelException cancel) throws IOException {
              if (!suppressCancel) {
                  super.handleCancelled(startDirectory, results, cancel);
              }
          }
  
          /** Handles a directory end by adding the File to the result set. */
          @Override
          protected void handleDirectoryEnd(final File directory, final int depth, final Collection<File> results) throws IOException {
              results.add(directory);
              if (cancelFileName.equals(directory.getName())) {
                  throw new CancelException(directory, depth);
              }
          }
  
          /** Handles a file by adding the File to the result set. */
          @Override
          protected void handleFile(final File file, final int depth, final Collection<File> results) throws IOException {
              results.add(file);
              if (cancelFileName.equals(file.getName())) {
                  throw new CancelException(file, depth);
              }
          }
      }
  
      /**
       * Test DirectoryWalker implementation that always returns false
       * from handleDirectoryStart()
       */
      private static final class TestFalseFileFinder extends TestFileFinder {
  
          protected TestFalseFileFinder(final FileFilter filter, final int depthLimit) {
              super(filter, depthLimit);
          }
  
          /** Always returns false. */
         @Override
         protected boolean handleDirectory(final File directory, final int depth, final Collection<File> results) {
             return false;
         }
     }
 
     /**
      * Test DirectoryWalker implementation that finds files in a directory hierarchy
      * applying a file filter.
      */
     private static class TestFileFinder extends DirectoryWalker<File> {
 
         protected TestFileFinder(final FileFilter filter, final int depthLimit) {
             super(filter, depthLimit);
         }
 
         protected TestFileFinder(final IOFileFilter dirFilter, final IOFileFilter fileFilter, final int depthLimit) {
             super(dirFilter, fileFilter, depthLimit);
         }
 
         /** Find files. */
         protected List<File> find(final File startDirectory) {
             final List<File> results = new ArrayList<>();
             try {
                 walk(startDirectory, results);
             } catch (final IOException ex) {
                 fail(ex.toString());
             }
             return results;
         }
 
         /** Handles a directory end by adding the File to the result set. */
         @Override
         protected void handleDirectoryEnd(final File directory, final int depth, final Collection<File> results) {
             results.add(directory);
         }
 
         /** Handles a file by adding the File to the result set. */
         @Override
         protected void handleFile(final File file, final int depth, final Collection<File> results) {
             results.add(file);
         }
     }
 
     /**
      * Test DirectoryWalker implementation that finds files in a directory hierarchy
      * applying a file filter.
      */
     private static final class TestFileFinderString extends DirectoryWalker<String> {
 
         protected TestFileFinderString(final FileFilter filter, final int depthLimit) {
             super(filter, depthLimit);
         }
 
         /** Find files. */
         protected List<String> find(final File startDirectory) {
             final List<String> results = new ArrayList<>();
             try {
                 walk(startDirectory, results);
             } catch (final IOException ex) {
                 fail(ex.toString());
             }
             return results;
         }
 
         /** Handles a file by adding the File to the result set. */
         @Override
         protected void handleFile(final File file, final int depth, final Collection<String> results) {
             results.add(file.toString());
         }
     }
 
     /**
      * Test DirectoryWalker implementation that finds files in a directory hierarchy
      * applying a file filter.
      */
     static class TestMultiThreadCancelWalker extends DirectoryWalker<File> {
         private final String cancelFileName;
         private final boolean suppressCancel;
         private boolean canceled;
         public List<File> results;
 
         TestMultiThreadCancelWalker(final String cancelFileName, final boolean suppressCancel) {
             this.cancelFileName = cancelFileName;
             this.suppressCancel = suppressCancel;
         }
 
         /** Find files. */
         protected List<File> find(final File startDirectory) throws IOException {
             results = new ArrayList<>();
             walk(startDirectory, results);
             return results;
         }
 
         /** Handles Cancel. */
         @Override
         protected void handleCancelled(final File startDirectory, final Collection<File> results, final CancelException cancel) throws IOException {
             if (!suppressCancel) {
                 super.handleCancelled(startDirectory, results, cancel);
             }
         }
 
         /** Handles a directory end by adding the File to the result set. */
         @Override
         protected void handleDirectoryEnd(final File directory, final int depth, final Collection<File> results) throws IOException {
             results.add(directory);
             assertFalse(canceled);
             if (cancelFileName.equals(directory.getName())) {
                 canceled = true;
             }
         }
 
         /** Handles a file by adding the File to the result set. */
         @Override
         protected void handleFile(final File file, final int depth, final Collection<File> results) throws IOException {
             results.add(file);
             assertFalse(canceled);
             if (cancelFileName.equals(file.getName())) {
                 canceled = true;
             }
         }
 
         /** Handles Cancelled. */
         @Override
         protected boolean handleIsCancelled(final File file, final int depth, final Collection<File> results) throws IOException {
             return canceled;
         }
     }
     // Directories
     private static final File current      = FileUtils.current();
     private static final File javaDir      = new File("src/main/java");
     private static final File orgDir       = new File(javaDir, "org");
 
     private static final File apacheDir    = new File(orgDir, "apache");
     private static final File commonsDir   = new File(apacheDir, "commons");
     private static final File ioDir        = new File(commonsDir, "io");
     private static final File outputDir    = new File(ioDir, "output");
     private static final File[] dirs       = {orgDir, apacheDir, commonsDir, ioDir, outputDir};
     // Files
     private static final File fileNameUtils = new File(ioDir, "FilenameUtils.java");
 
     private static final File ioUtils       = new File(ioDir, "IOUtils.java");
     private static final File proxyWriter   = new File(outputDir, "ProxyWriter.java");
     private static final File nullStream    = new File(outputDir, "NullOutputStream.java");
     private static final File[] ioFiles     = {fileNameUtils, ioUtils};
     private static final File[] outputFiles = {proxyWriter, nullStream};
 
     // Filters
     private static final IOFileFilter dirsFilter        = createNameFilter(dirs);
 
     private static final IOFileFilter ioFilesFilter = createNameFilter(ioFiles);
 
     private static final IOFileFilter outputFilesFilter = createNameFilter(outputFiles);
 
     private static final IOFileFilter ioDirAndFilesFilter = dirsFilter.or(ioFilesFilter);
 
     private static final IOFileFilter dirsAndFilesFilter = ioDirAndFilesFilter.or(outputFilesFilter);
 
     // Filter to exclude SVN files
     private static final IOFileFilter NOT_SVN = FileFilterUtils.makeSVNAware(null);
 
     /**
      * Create a name filter containing the names of the files
      * in the array.
      */
     private static IOFileFilter createNameFilter(final File[] files) {
         final String[] names = new String[files.length];
         for (int i = 0; i < files.length; i++) {
             names[i] = files[i].getName();
         }
         return new NameFileFilter(names);
     }
 
     /**
      * Check the files in the array are in the results list.
      */
     private void checkContainsFiles(final String prefix, final File[] files, final Collection<File> results) {
         for (int i = 0; i < files.length; i++) {
             assertTrue(results.contains(files[i]), prefix + "[" + i + "] " + files[i]);
         }
     }
 
     private void checkContainsString(final String prefix, final File[] files, final Collection<String> results) {
         for (int i = 0; i < files.length; i++) {
             assertTrue(results.contains(files[i].toString()), prefix + "[" + i + "] " + files[i]);
         }
     }
 
     /**
      * Extract the directories.
      */
     private List<File> directoriesOnly(final Collection<File> results) {
         final List<File> list = new ArrayList<>(results.size());
         for (final File file : results) {
             if (file.isDirectory()) {
                 list.add(file);
             }
         }
         return list;
     }
 
     /**
      * Extract the files.
      */
     private List<File> filesOnly(final Collection<File> results) {
         final List<File> list = new ArrayList<>(results.size());
         for (final File file : results) {
             if (file.isFile()) {
                 list.add(file);
             }
         }
         return list;
     }
 
     /**
      * Test Cancel
      */
     @Test
     void testCancel() {
         String cancelName = null;
 
         // Cancel on a file
         try {
             cancelName = "DirectoryWalker.java";
             new TestCancelWalker(cancelName, false).find(javaDir);
             fail("CancelException not thrown for '" + cancelName + "'");
         } catch (final DirectoryWalker.CancelException cancel) {
             assertEquals(cancelName, cancel.getFile().getName(), "File:  " + cancelName);
             assertEquals(5, cancel.getDepth(), "Depth: " + cancelName);
         } catch (final IOException ex) {
             fail("IOException: " + cancelName + " " + ex);
         }
 
         // Cancel on a directory
         try {
             cancelName = "commons";
             new TestCancelWalker(cancelName, false).find(javaDir);
             fail("CancelException not thrown for '" + cancelName + "'");
         } catch (final DirectoryWalker.CancelException cancel) {
             assertEquals(cancelName, cancel.getFile().getName(), "File:  " + cancelName);
             assertEquals(3, cancel.getDepth(), "Depth: " + cancelName);
         } catch (final IOException ex) {
             fail("IOException: " + cancelName + " " + ex);
         }
 
         // Suppress CancelException (use same file name as preceding test)
         try {
             final List<File> results = new TestCancelWalker(cancelName, true).find(javaDir);
             final File lastFile = results.get(results.size() - 1);
             assertEquals(cancelName, lastFile.getName(), "Suppress:  " + cancelName);
         } catch (final IOException ex) {
             fail("Suppress threw " + ex);
         }
 
     }
 
     /**
      * Test Filtering
      */
     @Test
     void testFilter() {
         final List<File> results = new TestFileFinder(dirsAndFilesFilter, -1).find(javaDir);
         assertEquals(1 + dirs.length + ioFiles.length + outputFiles.length, results.size(), "Result Size");
         assertTrue(results.contains(javaDir), "Start Dir");
         checkContainsFiles("Dir", dirs, results);
         checkContainsFiles("IO File", ioFiles, results);
         checkContainsFiles("Output File", outputFiles, results);
     }
 
     /**
      * Test Filtering and limit to depth 0
      */
     @Test
     void testFilterAndLimitA() {
         final List<File> results = new TestFileFinder(NOT_SVN, 0).find(javaDir);
         assertEquals(1, results.size(), "[A] Result Size");
         assertTrue(results.contains(javaDir), "[A] Start Dir");
     }
 
     /**
      * Test Filtering and limit to depth 1
      */
     @Test
     void testFilterAndLimitB() {
         final List<File> results = new TestFileFinder(NOT_SVN, 1).find(javaDir);
         assertEquals(2, results.size(), "[B] Result Size");
         assertTrue(results.contains(javaDir), "[B] Start Dir");
         assertTrue(results.contains(orgDir), "[B] Org Dir");
     }
 
     /**
      * Test Filtering and limit to depth 3
      */
     @Test
     void testFilterAndLimitC() {
         final List<File> results = new TestFileFinder(NOT_SVN, 3).find(javaDir);
         assertEquals(4, results.size(), "[C] Result Size");
         assertTrue(results.contains(javaDir), "[C] Start Dir");
         assertTrue(results.contains(orgDir), "[C] Org Dir");
         assertTrue(results.contains(apacheDir), "[C] Apache Dir");
         assertTrue(results.contains(commonsDir), "[C] Commons Dir");
     }
 
     /**
      * Test Filtering and limit to depth 5
      */
     @Test
     void testFilterAndLimitD() {
         final List<File> results = new TestFileFinder(dirsAndFilesFilter, 5).find(javaDir);
         assertEquals(1 + dirs.length + ioFiles.length, results.size(), "[D] Result Size");
         assertTrue(results.contains(javaDir), "[D] Start Dir");
         checkContainsFiles("[D] Dir", dirs, results);
         checkContainsFiles("[D] File", ioFiles, results);
     }
 
     /**
      * Test separate dir and file filters
      */
     @Test
     void testFilterDirAndFile1() {
         final List<File> results = new TestFileFinder(dirsFilter, ioFilesFilter, -1).find(javaDir);
         assertEquals(1 + dirs.length + ioFiles.length, results.size(), "[DirAndFile1] Result Size");
         assertTrue(results.contains(javaDir), "[DirAndFile1] Start Dir");
         checkContainsFiles("[DirAndFile1] Dir", dirs, results);
         checkContainsFiles("[DirAndFile1] File", ioFiles, results);
     }
 
     /**
      * Test separate dir and file filters
      */
     @Test
     void testFilterDirAndFile2() {
         final List<File> results = new TestFileFinder(null, null, -1).find(javaDir);
         assertTrue(results.size() > 1 + dirs.length + ioFiles.length, "[DirAndFile2] Result Size");
         assertTrue(results.contains(javaDir), "[DirAndFile2] Start Dir");
         checkContainsFiles("[DirAndFile2] Dir", dirs, results);
         checkContainsFiles("[DirAndFile2] File", ioFiles, results);
     }
 
     /**
      * Test separate dir and file filters
      */
     @Test
     void testFilterDirAndFile3() {
         final List<File> results = new TestFileFinder(dirsFilter, null, -1).find(javaDir);
         final List<File> resultDirs = directoriesOnly(results);
         assertEquals(1 + dirs.length, resultDirs.size(), "[DirAndFile3] Result Size");
         assertTrue(results.contains(javaDir), "[DirAndFile3] Start Dir");
         checkContainsFiles("[DirAndFile3] Dir", dirs, resultDirs);
     }
 
     /**
      * Test separate dir and file filters
      */
     @Test
     void testFilterDirAndFile4() {
         final List<File> results = new TestFileFinder(null, ioFilesFilter, -1).find(javaDir);
         final List<File> resultFiles = filesOnly(results);
         assertEquals(ioFiles.length, resultFiles.size(), "[DirAndFile4] Result Size");
         assertTrue(results.contains(javaDir), "[DirAndFile4] Start Dir");
         checkContainsFiles("[DirAndFile4] File", ioFiles, resultFiles);
     }
 
     /**
      * Test Filtering
      */
     @Test
     void testFilterString() {
         final List<String> results = new TestFileFinderString(dirsAndFilesFilter, -1).find(javaDir);
         assertEquals(results.size(), outputFiles.length + ioFiles.length, "Result Size");
         checkContainsString("IO File", ioFiles, results);
         checkContainsString("Output File", outputFiles, results);
     }
 
     /**
      * test an invalid start directory
      */
     @Test
     void testHandleStartDirectoryFalse() {
 
         final List<File> results = new TestFalseFileFinder(null, -1).find(current);
         assertEquals(0, results.size(), "Result Size");
 
     }
 
     /**
      * Test Limiting to current directory
      */
     @Test
     void testLimitToCurrent() {
         final List<File> results = new TestFileFinder(null, 0).find(current);
         assertEquals(1, results.size(), "Result Size");
         assertTrue(results.contains(FileUtils.current()), "Current Dir");
     }
 
     /**
      * test an invalid start directory
      */
     @Test
     void testMissingStartDirectory() {
 
         // TODO is this what we want with invalid directory?
         final File invalidDir = new File("invalid-dir");
         final List<File> results = new TestFileFinder(null, -1).find(invalidDir);
         assertEquals(1, results.size(), "Result Size");
         assertTrue(results.contains(invalidDir), "Current Dir");
 
         assertThrows(NullPointerException.class, () -> new TestFileFinder(null, -1).find(null));
     }
 
     /**
      * Test Cancel
      */
     @Test
     void testMultiThreadCancel() {
         String cancelName = "DirectoryWalker.java";
         TestMultiThreadCancelWalker walker = new TestMultiThreadCancelWalker(cancelName, false);
         // Cancel on a file
         try {
             walker.find(javaDir);
             fail("CancelException not thrown for '" + cancelName + "'");
         } catch (final DirectoryWalker.CancelException cancel) {
             final File last = walker.results.get(walker.results.size() - 1);
             assertEquals(cancelName, last.getName());
             assertEquals(5, cancel.getDepth(), "Depth: " + cancelName);
         } catch (final IOException ex) {
             fail("IOException: " + cancelName + " " + ex);
         }
 
         // Cancel on a directory
         try {
             cancelName = "commons";
             walker = new TestMultiThreadCancelWalker(cancelName, false);
             walker.find(javaDir);
             fail("CancelException not thrown for '" + cancelName + "'");
         } catch (final DirectoryWalker.CancelException cancel) {
             assertEquals(cancelName, cancel.getFile().getName(), "File:  " + cancelName);
             assertEquals(3, cancel.getDepth(), "Depth: " + cancelName);
         } catch (final IOException ex) {
             fail("IOException: " + cancelName + " " + ex);
         }
 
         // Suppress CancelException (use same file name as preceding test)
         try {
             walker = new TestMultiThreadCancelWalker(cancelName, true);
             final List<File> results = walker.find(javaDir);
             final File lastFile = results.get(results.size() - 1);
             assertEquals(cancelName, lastFile.getName(), "Suppress:  " + cancelName);
         } catch (final IOException ex) {
             fail("Suppress threw " + ex);
         }
 
     }
 
 }