/*
    * 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.filefilter;
  
  import java.io.File;
  import java.io.FileFilter;
  import java.io.FilenameFilter;
  import java.io.IOException;
  import java.nio.file.FileVisitResult;
  import java.nio.file.Path;
  import java.nio.file.attribute.BasicFileAttributes;
  import java.util.List;
  import java.util.Objects;
  
  import org.apache.commons.io.file.PathFilter;
  import org.apache.commons.io.file.PathVisitor;
  import org.apache.commons.io.function.IOSupplier;
  
  /**
   * Abstracts the implementation of the {@link FileFilter} (IO), {@link FilenameFilter} (IO), {@link PathFilter} (NIO)
   * interfaces via our own {@link IOFileFilter} interface.
   * <p>
   * Note that a subclass MUST override one of the {@code accept} methods, otherwise that subclass will infinitely loop.
   * </p>
   *
   * @since 1.0
   */
  public abstract class AbstractFileFilter implements IOFileFilter, PathVisitor {
  
      static FileVisitResult toDefaultFileVisitResult(final boolean accept) {
          return accept ? FileVisitResult.CONTINUE : FileVisitResult.TERMINATE;
      }
  
      /**
       * What to do when this filter accepts.
       */
      private final FileVisitResult onAccept;
  
      /**
       * What to do when this filter rejects.
       */
      private final FileVisitResult onReject;
  
      /**
       * Constructs a new instance.
       */
      public AbstractFileFilter() {
          this(FileVisitResult.CONTINUE, FileVisitResult.TERMINATE);
      }
  
      /**
       * Constructs a new instance.
       *
       * @param onAccept What to do on acceptance.
       * @param onReject What to do on rejection.
       * @since 2.12.0.
       */
      protected AbstractFileFilter(final FileVisitResult onAccept, final FileVisitResult onReject) {
          this.onAccept = onAccept;
          this.onReject = onReject;
      }
  
      /**
       * Tests to see if the File should be accepted by this filter.
       *
       * @param file the File to check.
       * @return true if this file matches the test.
       */
      @Override
      public boolean accept(final File file) {
          Objects.requireNonNull(file, "file");
          return accept(file.getParentFile(), file.getName());
      }
  
      /**
       * Tests to see if the File should be accepted by this filter.
       *
       * @param dir the directory File to check.
       * @param name the file name within the directory to check.
       * @return true if this file matches the test.
       */
      @Override
      public boolean accept(final File dir, final String name) {
          Objects.requireNonNull(name, "name");
          return accept(new File(dir, name));
     }
 
     void append(final List<?> list, final StringBuilder buffer) {
         for (int i = 0; i < list.size(); i++) {
             if (i > 0) {
                 buffer.append(",");
             }
             buffer.append(list.get(i));
         }
     }
 
     void append(final Object[] array, final StringBuilder buffer) {
         for (int i = 0; i < array.length; i++) {
             if (i > 0) {
                 buffer.append(",");
             }
             buffer.append(array[i]);
         }
     }
 
     FileVisitResult get(final IOSupplier<FileVisitResult> supplier) {
         try {
             return supplier.get();
         } catch (final IOException e) {
             return handle(e);
         }
     }
 
     /**
      * Handles exceptions caught while accepting.
      *
      * @param t the caught Throwable.
      * @return the given Throwable.
      * @since 2.9.0
      */
     protected FileVisitResult handle(final Throwable t) {
         return FileVisitResult.TERMINATE;
     }
 
     boolean isDirectory(final File file) {
         return file != null && file.isDirectory();
     }
 
     boolean isFile(final File file) {
         return file != null && file.isFile();
     }
 
     @Override
     public FileVisitResult postVisitDirectory(final Path dir, final IOException exc) throws IOException {
         return FileVisitResult.CONTINUE;
     }
 
     @Override
     public FileVisitResult preVisitDirectory(final Path dir, final BasicFileAttributes attributes) throws IOException {
         return accept(dir, attributes);
     }
 
     /**
      * Converts a boolean into a FileVisitResult.
      *
      * @param accept accepted or rejected.
      * @return a FileVisitResult.
      */
     FileVisitResult toFileVisitResult(final boolean accept) {
         return accept ? onAccept : onReject;
     }
 
     /**
      * Provides a String representation of this file filter.
      *
      * @return a String representation.
      */
     @Override
     public String toString() {
         return getClass().getSimpleName();
     }
 
     @Override
     public FileVisitResult visitFile(final Path file, final BasicFileAttributes attributes) throws IOException {
         return accept(file, attributes);
     }
 
     @Override
     public FileVisitResult visitFileFailed(final Path file, final IOException exc) throws IOException {
         return FileVisitResult.CONTINUE;
     }
 
 }