/*
    * 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;
  
  import java.io.File;
  import java.io.IOException;
  import java.nio.file.DirectoryStream;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.SortedMap;
  import java.util.TreeMap;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.apache.logging.log4j.Logger;
  import org.apache.logging.log4j.LoggingException;
  import org.apache.logging.log4j.core.appender.rolling.action.Action;
  import org.apache.logging.log4j.core.appender.rolling.action.CompositeAction;
  import org.apache.logging.log4j.core.lookup.StrSubstitutor;
  import org.apache.logging.log4j.core.pattern.NotANumber;
  import org.apache.logging.log4j.status.StatusLogger;
  
  /**
   *
   */
  public abstract class AbstractRolloverStrategy implements RolloverStrategy {
  
      /**
       * Allow subclasses access to the status logger without creating another instance.
       */
      protected static final Logger LOGGER = StatusLogger.getLogger();
  
      protected final StrSubstitutor strSubstitutor;
  
      protected AbstractRolloverStrategy(final StrSubstitutor strSubstitutor) {
          this.strSubstitutor = strSubstitutor;
      }
  
  
      public StrSubstitutor getStrSubstitutor() {
          return strSubstitutor;
      }
  
      protected Action merge(final Action compressAction, final List<Action> custom, final boolean stopOnError) {
          if (custom.isEmpty()) {
              return compressAction;
          }
          if (compressAction == null) {
              return new CompositeAction(custom, stopOnError);
          }
          final List<Action> all = new ArrayList<>();
          all.add(compressAction);
          all.addAll(custom);
          return new CompositeAction(all, stopOnError);
      }
  
      protected int suffixLength(final String lowFilename) {
          for (final FileExtension extension : FileExtension.values()) {
              if (extension.isExtensionFor(lowFilename)) {
                  return extension.length();
              }
          }
          return 0;
      }
  
  
      protected SortedMap<Integer, Path> getEligibleFiles(final RollingFileManager manager) {
          return getEligibleFiles(manager, true);
      }
  
      protected SortedMap<Integer, Path> getEligibleFiles(final RollingFileManager manager,
                                                          final boolean isAscending) {
          final StringBuilder buf = new StringBuilder();
          final String pattern = manager.getPatternProcessor().getPattern();
          manager.getPatternProcessor().formatFileName(strSubstitutor, buf, NotANumber.NAN);
          return getEligibleFiles(buf.toString(), pattern, isAscending);
      }
  
      protected SortedMap<Integer, Path> getEligibleFiles(final String path, final String pattern) {
          return getEligibleFiles(path, pattern, true);
      }
  
      protected SortedMap<Integer, Path> getEligibleFiles(final String path, final String logfilePattern, final boolean isAscending) {
         final TreeMap<Integer, Path> eligibleFiles = new TreeMap<>();
         final File file = new File(path);
         File parent = file.getParentFile();
         if (parent == null) {
             parent = new File(".");
         } else {
             parent.mkdirs();
         }
         if (!logfilePattern.contains("%i")) {
             return eligibleFiles;
         }
         final Path dir = parent.toPath();
         String fileName = file.getName();
         final int suffixLength = suffixLength(fileName);
         if (suffixLength > 0) {
             fileName = fileName.substring(0, fileName.length() - suffixLength) + ".*";
         }
         final String filePattern = fileName.replace(NotANumber.VALUE, "(\\d+)");
         final Pattern pattern = Pattern.compile(filePattern);
 
         try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir)) {
             for (final Path entry: stream) {
                 final Matcher matcher = pattern.matcher(entry.toFile().getName());
                 if (matcher.matches()) {
                     final Integer index = Integer.parseInt(matcher.group(1));
                     eligibleFiles.put(index, entry);
                 }
             }
         } catch (final IOException ioe) {
             throw new LoggingException("Error reading folder " + dir + " " + ioe.getMessage(), ioe);
         }
         return isAscending? eligibleFiles : eligibleFiles.descendingMap();
     }
 }