/*
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2026, QOS.ch. All rights reserved.
    *
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v2.0 as published by
    * the Eclipse Foundation
    *
    *   or (per the licensee's choosing)
   *
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package ch.qos.logback.core.rolling;
  
  import ch.qos.logback.core.FileAppender;
  import ch.qos.logback.core.rolling.helper.CompressionMode;
  import ch.qos.logback.core.rolling.helper.FileNamePattern;
  import ch.qos.logback.core.spi.ContextAwareBase;
  
  import static ch.qos.logback.core.util.Loader.isClassLoadable;
  
  /**
   * Implements methods common to most, it not all, rolling policies. Currently
   * such methods are limited to a compression mode getter/setter.
   *
   * @author Ceki Gülcü
   */
  public abstract class RollingPolicyBase extends ContextAwareBase implements RollingPolicy {
      protected CompressionMode compressionMode = CompressionMode.NONE;
  
      FileNamePattern fileNamePattern;
      // fileNamePatternStr is always slashified, see setter
      protected String fileNamePatternStr;
  
      private FileAppender<?> parent;
  
      // use to name files within zip file, i.e. the zipEntry
      FileNamePattern zipEntryFileNamePattern;
      private boolean started;
  
      /**
       * Given the FileNamePattern string, this method determines the compression mode
       * depending on last letters of the fileNamePatternStr. Patterns ending with .gz
       * imply GZIP compression, endings with '.zip' imply ZIP compression, endings with
       * .xz imply XZ compression. Otherwise and by default, there is no compression.
       *
       */
      protected void determineCompressionMode() {
          if (fileNamePatternStr.endsWith(CompressionMode.GZ_SUFFIX)) {
              addInfo("Will use gz compression");
              compressionMode = CompressionMode.GZ;
          } else if (fileNamePatternStr.endsWith(CompressionMode.ZIP_SUFFIX)) {
              addInfo("Will use zip compression");
              compressionMode = CompressionMode.ZIP;
          } else if (fileNamePatternStr.endsWith(CompressionMode.XZ_SUFFIX)) {
              addInfo("Will use xz compression");
              compressionMode = CompressionMode.XZ;
          } else {
              addInfo("No compression will be used");
              compressionMode = CompressionMode.NONE;
          }
      }
  
      /**
       * If compression mode is XZ but the XZ library is missing, then fallback to GZ compression.
       */
      protected void adjustCompressionModeAndFileNamePatternStrIfNecessary() {
          if (compressionMode == compressionMode.XZ) {
              boolean xzLibraryLoadable = isClassLoadable("org.tukaani.xz.XZOutputStream", getContext());
              if (!xzLibraryLoadable) {
                  addWarn("XZ library missing, falling back to GZ compression");
                  compressionMode = CompressionMode.GZ;
                  fileNamePatternStr = replaceSuffix(fileNamePatternStr, CompressionMode.XZ_SUFFIX, CompressionMode.GZ_SUFFIX);
              }
          }
      }
  
      private String replaceSuffix(String input, String existingSuffix, String newSuffix) {
          int existingSuffixLen = existingSuffix.length();
          if (input.endsWith(existingSuffix)) {
              return input.substring(0, input.length() - existingSuffixLen) + newSuffix;
          } else {
              // unreachable code
              throw new IllegalArgumentException("[" + input + "] should end with "+existingSuffix);
          }
      }
  
      public void setFileNamePattern(String fnp) {
          fileNamePatternStr = fnp;
      }
  
      public String getFileNamePattern() {
          return fileNamePatternStr;
      }
  
      public CompressionMode getCompressionMode() {
          return compressionMode;
      }
 
     public boolean isStarted() {
         return started;
     }
 
     public void start() {
         started = true;
     }
 
     public void stop() {
         started = false;
     }
 
     public void setParent(FileAppender<?> appender) {
         this.parent = appender;
     }
 
     public boolean isParentPrudent() {
         return parent.isPrudent();
     }
 
     public String getParentsRawFileProperty() {
         return parent.rawFileProperty();
     }
 }