/*
    * 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.util;
  
  import java.io.InterruptedIOException;
  import java.util.Locale;
  import java.util.Properties;
  
  import org.apache.logging.log4j.Level;
  import org.apache.logging.log4j.Logger;
  import org.apache.logging.log4j.status.StatusLogger;
  import org.apache.logging.log4j.util.PropertiesUtil;
  import org.apache.logging.log4j.util.Strings;
  
  /**
   * A convenience class to convert property values to specific types.
   */
  public final class OptionConverter {
  
      private static final Logger LOGGER = StatusLogger.getLogger();
  
      private static final String DELIM_START = "${";
      private static final char DELIM_STOP = '}';
      private static final int DELIM_START_LEN = 2;
      private static final int DELIM_STOP_LEN = 1;
      private static final int ONE_K = 1024;
  
      /**
       * OptionConverter is a static class.
       */
      private OptionConverter() {
      }
  
      public static String[] concatenateArrays(final String[] l, final String[] r) {
          final int len = l.length + r.length;
          final String[] a = new String[len];
  
          System.arraycopy(l, 0, a, 0, l.length);
          System.arraycopy(r, 0, a, l.length, r.length);
  
          return a;
      }
  
      public static String convertSpecialChars(final String s) {
          char c;
          final int len = s.length();
          final StringBuilder sbuf = new StringBuilder(len);
  
          int i = 0;
          while (i < len) {
              c = s.charAt(i++);
              if (c == '\\') {
                  c = s.charAt(i++);
                  switch (c) {
                  case 'n':
                      c = '\n';
                      break;
                  case 'r':
                      c = '\r';
                      break;
                  case 't':
                      c = '\t';
                      break;
                  case 'f':
                      c = '\f';
                      break;
                  case 'b':
                      c = '\b';
                      break;
                  case '"':
                      c = '\"';
                      break;
                  case '\'':
                      c = '\'';
                      break;
                  case '\\':
                      c = '\\';
                      break;
                  default:
                      // there is no default case.
                  }
              }
              sbuf.append(c);
          }
          return sbuf.toString();
     }
 
     public static Object instantiateByKey(final Properties props, final String key, final Class<?> superClass,
                                    final Object defaultValue) {
 
         // Get the value of the property in string form
         final String className = findAndSubst(key, props);
         if (className == null) {
             LOGGER.error("Could not find value for key {}", key);
             return defaultValue;
         }
         // Trim className to avoid trailing spaces that cause problems.
         return OptionConverter.instantiateByClassName(className.trim(), superClass,
             defaultValue);
     }
 
     /**
      * If <code>value</code> is "true", then {@code true} is
      * returned. If <code>value</code> is "false", then
      * {@code false} is returned. Otherwise, <code>default</code> is
      * returned.
      *
      * <p>Case of value is unimportant.</p>
      * @param value The value to convert.
      * @param defaultValue The default value.
      * @return true or false, depending on the value and/or default.
      */
     public static boolean toBoolean(final String value, final boolean defaultValue) {
         if (value == null) {
             return defaultValue;
         }
         final String trimmedVal = value.trim();
         if ("true".equalsIgnoreCase(trimmedVal)) {
             return true;
         }
         if ("false".equalsIgnoreCase(trimmedVal)) {
             return false;
         }
         return defaultValue;
     }
 
     /**
      * Convert the String value to an int.
      * @param value The value as a String.
      * @param defaultValue The default value.
      * @return The value as an int.
      */
     public static int toInt(final String value, final int defaultValue) {
         if (value != null) {
             final String s = value.trim();
             try {
                 return Integer.parseInt(s);
             } catch (final NumberFormatException e) {
                 LOGGER.error("[{}] is not in proper int form.", s, e);
             }
         }
         return defaultValue;
     }
 
     public static Level toLevel(String value, Level defaultValue) {
         if(value == null) {
             return defaultValue;
         }
 
         value = value.trim();
 
         int hashIndex = value.indexOf('#');
         if (hashIndex == -1) {
             if("NULL".equalsIgnoreCase(value)) {
                 return null;
             } else {
                 // no class name specified : use standard Level class
                 return Level.toLevel(value, defaultValue);
             }
         }
 
         Level result = defaultValue;
 
         String clazz = value.substring(hashIndex+1);
         String levelName = value.substring(0, hashIndex);
 
         // This is degenerate case but you never know.
         if("NULL".equalsIgnoreCase(levelName)) {
             return null;
         }
 
         LOGGER.debug("toLevel" + ":class=[" + clazz + "]"
             + ":pri=[" + levelName + "]");
 
         try {
             Class customLevel = Loader.loadClass(clazz);
 
             // get a ref to the specified class' static method
             // toLevel(String, org.apache.log4j.Level)
             Class[] paramTypes = new Class[] { String.class, Level.class
             };
             java.lang.reflect.Method toLevelMethod =
                 customLevel.getMethod("toLevel", paramTypes);
 
             // now call the toLevel method, passing level string + default
             Object[] params = new Object[] {levelName, defaultValue};
             Object o = toLevelMethod.invoke(null, params);
 
             result = (Level) o;
         } catch(ClassNotFoundException e) {
             LOGGER.warn("custom level class [" + clazz + "] not found.");
         } catch(NoSuchMethodException e) {
             LOGGER.warn("custom level class [" + clazz + "]"
                 + " does not have a class function toLevel(String, Level)", e);
         } catch(java.lang.reflect.InvocationTargetException e) {
             if (e.getTargetException() instanceof InterruptedException
                 || e.getTargetException() instanceof InterruptedIOException) {
                 Thread.currentThread().interrupt();
             }
             LOGGER.warn("custom level class [" + clazz + "]" + " could not be instantiated", e);
         } catch(ClassCastException e) {
             LOGGER.warn("class [" + clazz + "] is not a subclass of org.apache.log4j.Level", e);
         } catch(IllegalAccessException e) {
             LOGGER.warn("class ["+clazz+ "] cannot be instantiated due to access restrictions", e);
         } catch(RuntimeException e) {
             LOGGER.warn("class ["+clazz+"], level [" + levelName + "] conversion failed.", e);
         }
         return result;
     }
 
     /**
      *
      * @param value The size of the file as a String.
      * @param defaultValue The default value.
      * @return The size of the file as a long.
      */
     public static long toFileSize(final String value, final long defaultValue) {
         if (value == null) {
             return defaultValue;
         }
 
         String str = value.trim().toUpperCase(Locale.ENGLISH);
         long multiplier = 1;
         int index;
 
         if ((index = str.indexOf("KB")) != -1) {
             multiplier = ONE_K;
             str = str.substring(0, index);
         } else if ((index = str.indexOf("MB")) != -1) {
             multiplier = ONE_K * ONE_K;
             str = str.substring(0, index);
         } else if ((index = str.indexOf("GB")) != -1) {
             multiplier = ONE_K * ONE_K * ONE_K;
             str = str.substring(0, index);
         }
         try {
             return Long.parseLong(str) * multiplier;
         } catch (final NumberFormatException e) {
             LOGGER.error("[{}] is not in proper int form.", str);
             LOGGER.error("[{}] not in expected format.", value, e);
         }
         return defaultValue;
     }
 
     /**
      * Find the value corresponding to <code>key</code> in
      * <code>props</code>. Then perform variable substitution on the
      * found value.
      * @param key The key to locate.
      * @param props The properties.
      * @return The String after substitution.
      */
     public static String findAndSubst(final String key, final Properties props) {
         final String value = props.getProperty(key);
         if (value == null) {
             return null;
         }
 
         try {
             return substVars(value, props);
         } catch (final IllegalArgumentException e) {
             LOGGER.error("Bad option value [{}].", value, e);
             return value;
         }
     }
 
     /**
      * Instantiate an object given a class name. Check that the
      * <code>className</code> is a subclass of
      * <code>superClass</code>. If that test fails or the object could
      * not be instantiated, then <code>defaultValue</code> is returned.
      *
      * @param className    The fully qualified class name of the object to instantiate.
      * @param superClass   The class to which the new object should belong.
      * @param defaultValue The object to return in case of non-fulfillment
      * @return The created object.
      */
     public static Object instantiateByClassName(final String className, final Class<?> superClass,
                                          final Object defaultValue) {
         if (className != null) {
             try {
                 final Class<?> classObj = Loader.loadClass(className);
                 if (!superClass.isAssignableFrom(classObj)) {
                     LOGGER.error("A \"{}\" object is not assignable to a \"{}\" variable.", className,
                         superClass.getName());
                     LOGGER.error("The class \"{}\" was loaded by [{}] whereas object of type [{}] was loaded by [{}].",
                         superClass.getName(), superClass.getClassLoader(), classObj.getName());
                     return defaultValue;
                 }
                 return classObj.newInstance();
             } catch (final Exception e) {
                 LOGGER.error("Could not instantiate class [{}].", className, e);
             }
         }
         return defaultValue;
     }
 
 
     /**
      * Perform variable substitution in string <code>val</code> from the
      * values of keys found in the system propeties.
      *
      * <p>The variable substitution delimiters are <b>${</b> and <b>}</b>.</p>
      *
      * <p>For example, if the System properties contains "key=value", then
      * the call</p>
      * <pre>
      * String s = OptionConverter.substituteVars("Value of key is ${key}.");
      * </pre>
      * <p>
      * will set the variable <code>s</code> to "Value of key is value.".
      * </p>
      * <p>If no value could be found for the specified key, then the
      * <code>props</code> parameter is searched, if the value could not
      * be found there, then substitution defaults to the empty string.</p>
      *
      * <p>For example, if system properties contains no value for the key
      * "inexistentKey", then the call
      * </p>
      * <pre>
      * String s = OptionConverter.subsVars("Value of inexistentKey is [${inexistentKey}]");
      * </pre>
      * <p>
      * will set <code>s</code> to "Value of inexistentKey is []"
      * </p>
      * <p>An {@link java.lang.IllegalArgumentException} is thrown if
      * <code>val</code> contains a start delimeter "${" which is not
      * balanced by a stop delimeter "}". </p>
      *
      * @param val The string on which variable substitution is performed.
      * @param props The properties to use for substitution.
      * @return The String after substitution.
      * @throws IllegalArgumentException if <code>val</code> is malformed.
      */
     public static String substVars(final String val, final Properties props) throws
         IllegalArgumentException {
 
         final StringBuilder sbuf = new StringBuilder();
 
         int i = 0;
         int j;
         int k;
 
         while (true) {
             j = val.indexOf(DELIM_START, i);
             if (j == -1) {
                 // no more variables
                 if (i == 0) { // this is a simple string
                     return val;
                 }
                 // add the tail string which contails no variables and return the result.
                 sbuf.append(val.substring(i, val.length()));
                 return sbuf.toString();
             }
             sbuf.append(val.substring(i, j));
             k = val.indexOf(DELIM_STOP, j);
             if (k == -1) {
                 throw new IllegalArgumentException(Strings.dquote(val)
                     + " has no closing brace. Opening brace at position " + j
                     + '.');
             }
             j += DELIM_START_LEN;
             final String key = val.substring(j, k);
             // first try in System properties
             String replacement = PropertiesUtil.getProperties().getStringProperty(key, null);
             // then try props parameter
             if (replacement == null && props != null) {
                 replacement = props.getProperty(key);
             }
 
             if (replacement != null) {
                 // Do variable substitution on the replacement string
                 // such that we can solve "Hello ${x2}" as "Hello p1"
                 // the where the properties are
                 // x1=p1
                 // x2=${x1}
                 final String recursiveReplacement = substVars(replacement, props);
                 sbuf.append(recursiveReplacement);
             }
             i = k + DELIM_STOP_LEN;
         }
     }
 }