/*
    * 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.util;
  
  import ch.qos.logback.core.CoreConstants;
  
  import java.lang.module.ModuleDescriptor;
  import java.util.Optional;
  
  /**
   * @author Ceki Gülcü
   */
  public class EnvUtil {
  
      private EnvUtil() {
      }
  
  
      /**
       * <p>Returns the current version of logback-core, or null if data is not
       * available.
       * </p>
       *
       * @since 1.3.0
       * @return current version or null if missing version data
       * @deprecated See {@link VersionUtil#getVersionOfArtifact(Class)}
       */
      static public String logbackVersion() {
          return VersionUtil.getVersionOfArtifact(CoreConstants.class);
      }
  
      static public int getJDKVersion(String javaVersionStr) {
          int version = 0;
  
          for (char ch : javaVersionStr.toCharArray()) {
              if (Character.isDigit(ch)) {
                  version = (version * 10) + (ch - 48);
              } else if (version == 1) {
                  version = 0;
              } else {
                  break;
              }
          }
          return version;
      }
  
      static private boolean isJDK_N_OrHigher(int n) {
          String javaVersionStr = System.getProperty("java.version", "");
          if (javaVersionStr.isEmpty())
              return false;
  
          int version = getJDKVersion(javaVersionStr);
          return version > 0 && n <= version;
      }
  
      static public boolean isJDK5() {
          return isJDK_N_OrHigher(5);
      }
  
      static public boolean isJDK6OrHigher() {
          return isJDK_N_OrHigher(6);
      }
  
      static public boolean isJDK7OrHigher() {
          return isJDK_N_OrHigher(7);
      }
  
      static public boolean isJDK16OrHigher() {
          return isJDK_N_OrHigher(16);
      }
  
      static public boolean isJDK18OrHigher() {
          return isJDK_N_OrHigher(18);
      }
  
      /**
       * @since logback 1.3.12/1.4.12
       * @return true if runtime JDK is version 21 or higher
       */
      static public boolean isJDK21OrHigher() {
          return isJDK_N_OrHigher(21);
      }
  
      static public boolean isJaninoAvailable() {
          ClassLoader classLoader = EnvUtil.class.getClassLoader();
          try {
              Class<?> bindingClass = classLoader.loadClass("org.codehaus.janino.ScriptEvaluator");
              return (bindingClass != null);
         } catch (ClassNotFoundException e) {
             return false;
         }
     }
 
     public static boolean isMacOs() {
         String os = System.getProperty("os.name");
         // expected value is "Mac OS X"
         return os.toLowerCase().contains("mac");
     }
 
     public static boolean isWindows() {
         String os = System.getProperty("os.name");
         return os.startsWith("Windows");
     }
 
     static public boolean isClassAvailable(Class callerClass, String className) {
         ClassLoader classLoader = Loader.getClassLoaderOfClass(callerClass);
         try {
             Class<?> bindingClass = classLoader.loadClass(className);
             return (bindingClass != null);
         } catch (ClassNotFoundException e) {
             return false;
         }
     }
 
 }