/*
    * 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.logging.log4j.core.appender.rolling.action;
  
  import java.io.IOException;
  import java.nio.file.FileVisitOption;
  import java.nio.file.FileVisitor;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.nio.file.Paths;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.EnumSet;
  import java.util.List;
  import java.util.Set;
  import java.util.concurrent.TimeUnit;
  
  import org.apache.logging.log4j.core.lookup.StrSubstitutor;
  
  /**
   * Abstract action for processing files that are accepted by the specified PathFilters.
   */
  public abstract class AbstractPathAction extends AbstractAction {
  
      private final String basePathString;
      private final Set<FileVisitOption> options;
      private final int maxDepth;
      private final List<PathCondition> pathConditions;
      private final StrSubstitutor subst;
  
      /**
       * Creates a new AbstractPathAction that starts scanning for files to process from the specified base path.
       *
       * @param basePath base path from where to start scanning for files to process.
       * @param followSymbolicLinks whether to follow symbolic links. Default is false.
       * @param maxDepth The maxDepth parameter is the maximum number of levels of directories to visit. A value of 0
       *            means that only the starting file is visited, unless denied by the security manager. A value of
       *            MAX_VALUE may be used to indicate that all levels should be visited.
       * @param pathFilters an array of path filters (if more than one, they all need to accept a path before it is
       *            processed).
       */
      protected AbstractPathAction(final String basePath, final boolean followSymbolicLinks, final int maxDepth,
              final PathCondition[] pathFilters, final StrSubstitutor subst) {
          this.basePathString = basePath;
          this.options = followSymbolicLinks ? EnumSet.of(FileVisitOption.FOLLOW_LINKS)
                  : Collections.<FileVisitOption> emptySet();
          this.maxDepth = maxDepth;
          this.pathConditions = Arrays.asList(Arrays.copyOf(pathFilters, pathFilters.length));
          this.subst = subst;
      }
  
      @Override
      public boolean execute() throws IOException {
          return execute(createFileVisitor(getBasePath(), pathConditions));
      }
  
      public boolean execute(final FileVisitor<Path> visitor) throws IOException {
          final long start = System.nanoTime();
          LOGGER.debug("Starting {}", this);
  
          Files.walkFileTree(getBasePath(), options, maxDepth, visitor);
  
          final double duration = System.nanoTime() - start;
          LOGGER.debug("{} complete in {} seconds", getClass().getSimpleName(), duration / TimeUnit.SECONDS.toNanos(1));
  
          // TODO return (visitor.success || ignoreProcessingFailure)
          return true; // do not abort rollover even if processing failed
      }
  
      /**
       * Creates a new {@code FileVisitor<Path>} to pass to the {@link Files#walkFileTree(Path, Set, int, FileVisitor)}
       * method when the {@link #execute()} method is invoked.
       * <p>
       * The visitor is responsible for processing the files it encounters that are accepted by all filters.
       *
       * @param visitorBaseDir base dir from where to start scanning for files to process
       * @param conditions filters that determine if a file should be processed
       * @return a new {@code FileVisitor<Path>}
       */
      protected abstract FileVisitor<Path> createFileVisitor(final Path visitorBaseDir,
              final List<PathCondition> conditions);
  
      /**
       * Returns the base path from where to start scanning for files to delete. Lookups are resolved, so if the
      * configuration was <code>&lt;Delete basePath="${sys:user.home}/abc" /&gt;</code> then this method returns a path
      * to the "abc" file or directory in the user's home directory.
      *
      * @return the base path (all lookups resolved)
      */
     public Path getBasePath() {
         return Paths.get(subst.replace(getBasePathString()));
     }
 
     /**
      * Returns the base path as it was specified in the configuration. Lookups are not resolved.
      *
      * @return the base path as it was specified in the configuration
      */
     public String getBasePathString() {
         return basePathString;
     }
 
     public StrSubstitutor getStrSubstitutor() {
         return subst;
     }
 
     /**
      * Returns whether to follow symbolic links or not.
      *
      * @return the options
      */
     public Set<FileVisitOption> getOptions() {
         return Collections.unmodifiableSet(options);
     }
 
     /**
      * Returns whether to follow symbolic links or not.
      *
      * @return whether to follow symbolic links or not
      */
     public boolean isFollowSymbolicLinks() {
         return options.contains(FileVisitOption.FOLLOW_LINKS);
     }
 
     /**
      * Returns the the maximum number of directory levels to visit.
      *
      * @return the maxDepth
      */
     public int getMaxDepth() {
         return maxDepth;
     }
 
     /**
      * Returns the list of PathCondition objects.
      *
      * @return the pathFilters
      */
     public List<PathCondition> getPathConditions() {
         return Collections.unmodifiableList(pathConditions);
     }
 
     @Override
     public String toString() {
         return getClass().getSimpleName() + "[basePath=" + getBasePath() + ", options=" + options + ", maxDepth="
                 + maxDepth + ", conditions=" + pathConditions + "]";
     }
 }