/*
    * 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.message;
  
  import java.text.SimpleDateFormat;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Date;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  
  import org.apache.logging.log4j.util.StringBuilders;
  
  /**
   * Supports parameter formatting as used in ParameterizedMessage and ReusableParameterizedMessage.
   */
  final class ParameterFormatter {
      /**
       * Prefix for recursion.
       */
      static final String RECURSION_PREFIX = "[...";
      /**
       * Suffix for recursion.
       */
      static final String RECURSION_SUFFIX = "...]";
  
      /**
       * Prefix for errors.
       */
      static final String ERROR_PREFIX = "[!!!";
      /**
       * Separator for errors.
       */
      static final String ERROR_SEPARATOR = "=>";
      /**
       * Separator for error messages.
       */
      static final String ERROR_MSG_SEPARATOR = ":";
      /**
       * Suffix for errors.
       */
      static final String ERROR_SUFFIX = "!!!]";
  
      private static final char DELIM_START = '{';
      private static final char DELIM_STOP = '}';
      private static final char ESCAPE_CHAR = '\\';
  
      private static ThreadLocal<SimpleDateFormat> threadLocalSimpleDateFormat = new ThreadLocal<>();
  
      private ParameterFormatter() {
      }
  
      /**
       * Counts the number of unescaped placeholders in the given messagePattern.
       *
       * @param messagePattern the message pattern to be analyzed.
       * @return the number of unescaped placeholders.
       */
      static int countArgumentPlaceholders(final String messagePattern) {
          if (messagePattern == null) {
              return 0;
          }
          final int length = messagePattern.length();
          int result = 0;
          boolean isEscaped = false;
          for (int i = 0; i < length - 1; i++) {
              final char curChar = messagePattern.charAt(i);
              if (curChar == ESCAPE_CHAR) {
                  isEscaped = !isEscaped;
              } else if (curChar == DELIM_START) {
                  if (!isEscaped && messagePattern.charAt(i + 1) == DELIM_STOP) {
                      result++;
                      i++;
                  }
                  isEscaped = false;
              } else {
                  isEscaped = false;
              }
          }
          return result;
      }
  
      /**
       * Counts the number of unescaped placeholders in the given messagePattern.
      *
      * @param messagePattern the message pattern to be analyzed.
      * @return the number of unescaped placeholders.
      */
     static int countArgumentPlaceholders2(final String messagePattern, final int[] indices) {
         if (messagePattern == null) {
             return 0;
         }
         final int length = messagePattern.length();
         int result = 0;
         boolean isEscaped = false;
         for (int i = 0; i < length - 1; i++) {
             final char curChar = messagePattern.charAt(i);
             if (curChar == ESCAPE_CHAR) {
                 isEscaped = !isEscaped;
                 indices[0] = -1; // escaping means fast path is not available...
                 result++;
             } else if (curChar == DELIM_START) {
                 if (!isEscaped && messagePattern.charAt(i + 1) == DELIM_STOP) {
                     indices[result] = i;
                     result++;
                     i++;
                 }
                 isEscaped = false;
             } else {
                 isEscaped = false;
             }
         }
         return result;
     }
 
     /**
      * Counts the number of unescaped placeholders in the given messagePattern.
      *
      * @param messagePattern the message pattern to be analyzed.
      * @return the number of unescaped placeholders.
      */
     static int countArgumentPlaceholders3(final char[] messagePattern, final int length, final int[] indices) {
         int result = 0;
         boolean isEscaped = false;
         for (int i = 0; i < length - 1; i++) {
             final char curChar = messagePattern[i];
             if (curChar == ESCAPE_CHAR) {
                 isEscaped = !isEscaped;
             } else if (curChar == DELIM_START) {
                 if (!isEscaped && messagePattern[i + 1] == DELIM_STOP) {
                     indices[result] = i;
                     result++;
                     i++;
                 }
                 isEscaped = false;
             } else {
                 isEscaped = false;
             }
         }
         return result;
     }
 
     /**
      * Replace placeholders in the given messagePattern with arguments.
      *
      * @param messagePattern the message pattern containing placeholders.
      * @param arguments      the arguments to be used to replace placeholders.
      * @return the formatted message.
      */
     static String format(final String messagePattern, final Object[] arguments) {
         final StringBuilder result = new StringBuilder();
         final int argCount = arguments == null ? 0 : arguments.length;
         formatMessage(result, messagePattern, arguments, argCount);
         return result.toString();
     }
 
     /**
      * Replace placeholders in the given messagePattern with arguments.
      *
      * @param buffer the buffer to write the formatted message into
      * @param messagePattern the message pattern containing placeholders.
      * @param arguments      the arguments to be used to replace placeholders.
      */
     static void formatMessage2(final StringBuilder buffer, final String messagePattern,
             final Object[] arguments, final int argCount, final int[] indices) {
         if (messagePattern == null || arguments == null || argCount == 0) {
             buffer.append(messagePattern);
             return;
         }
         int previous = 0;
         for (int i = 0; i < argCount; i++) {
             buffer.append(messagePattern, previous, indices[i]);
             previous = indices[i] + 2;
             recursiveDeepToString(arguments[i], buffer, null);
         }
         buffer.append(messagePattern, previous, messagePattern.length());
     }
 
     /**
      * Replace placeholders in the given messagePattern with arguments.
      *
      * @param buffer the buffer to write the formatted message into
      * @param messagePattern the message pattern containing placeholders.
      * @param arguments      the arguments to be used to replace placeholders.
      */
     static void formatMessage3(final StringBuilder buffer, final char[] messagePattern, final int patternLength,
             final Object[] arguments, final int argCount, final int[] indices) {
         if (messagePattern == null) {
             return;
         }
         if (arguments == null || argCount == 0) {
             buffer.append(messagePattern);
             return;
         }
         int previous = 0;
         for (int i = 0; i < argCount; i++) {
             buffer.append(messagePattern, previous, indices[i]);
             previous = indices[i] + 2;
             recursiveDeepToString(arguments[i], buffer, null);
         }
         buffer.append(messagePattern, previous, patternLength);
     }
 
     /**
      * Replace placeholders in the given messagePattern with arguments.
      *
      * @param buffer the buffer to write the formatted message into
      * @param messagePattern the message pattern containing placeholders.
      * @param arguments      the arguments to be used to replace placeholders.
      */
     static void formatMessage(final StringBuilder buffer, final String messagePattern,
             final Object[] arguments, final int argCount) {
         if (messagePattern == null || arguments == null || argCount == 0) {
             buffer.append(messagePattern);
             return;
         }
         int escapeCounter = 0;
         int currentArgument = 0;
         int i = 0;
         final int len = messagePattern.length();
         for (; i < len - 1; i++) { // last char is excluded from the loop
             final char curChar = messagePattern.charAt(i);
             if (curChar == ESCAPE_CHAR) {
                 escapeCounter++;
             } else {
                 if (isDelimPair(curChar, messagePattern, i)) { // looks ahead one char
                     i++;
 
                     // write escaped escape chars
                     writeEscapedEscapeChars(escapeCounter, buffer);
 
                     if (isOdd(escapeCounter)) {
                         // i.e. escaped: write escaped escape chars
                         writeDelimPair(buffer);
                     } else {
                         // unescaped
                         writeArgOrDelimPair(arguments, argCount, currentArgument, buffer);
                         currentArgument++;
                     }
                 } else {
                     handleLiteralChar(buffer, escapeCounter, curChar);
                 }
                 escapeCounter = 0;
             }
         }
         handleRemainingCharIfAny(messagePattern, len, buffer, escapeCounter, i);
     }
 
     /**
      * Returns {@code true} if the specified char and the char at {@code curCharIndex + 1} in the specified message
      * pattern together form a "{}" delimiter pair, returns {@code false} otherwise.
      */
     // Profiling showed this method is important to log4j performance. Modify with care!
     // 22 bytes (allows immediate JVM inlining: < 35 bytes) LOG4J2-1096
     private static boolean isDelimPair(final char curChar, final String messagePattern, final int curCharIndex) {
         return curChar == DELIM_START && messagePattern.charAt(curCharIndex + 1) == DELIM_STOP;
     }
 
     /**
      * Detects whether the message pattern has been fully processed or if an unprocessed character remains and processes
      * it if necessary, returning the resulting position in the result char array.
      */
     // Profiling showed this method is important to log4j performance. Modify with care!
     // 28 bytes (allows immediate JVM inlining: < 35 bytes) LOG4J2-1096
     private static void handleRemainingCharIfAny(final String messagePattern, final int len,
             final StringBuilder buffer, final int escapeCounter, final int i) {
         if (i == len - 1) {
             final char curChar = messagePattern.charAt(i);
             handleLastChar(buffer, escapeCounter, curChar);
         }
     }
 
     /**
      * Processes the last unprocessed character and returns the resulting position in the result char array.
      */
     // Profiling showed this method is important to log4j performance. Modify with care!
     // 28 bytes (allows immediate JVM inlining: < 35 bytes) LOG4J2-1096
     private static void handleLastChar(final StringBuilder buffer, final int escapeCounter, final char curChar) {
         if (curChar == ESCAPE_CHAR) {
             writeUnescapedEscapeChars(escapeCounter + 1, buffer);
         } else {
             handleLiteralChar(buffer, escapeCounter, curChar);
         }
     }
 
     /**
      * Processes a literal char (neither an '\' escape char nor a "{}" delimiter pair) and returns the resulting
      * position.
      */
     // Profiling showed this method is important to log4j performance. Modify with care!
     // 16 bytes (allows immediate JVM inlining: < 35 bytes) LOG4J2-1096
     private static void handleLiteralChar(final StringBuilder buffer, final int escapeCounter, final char curChar) {
         // any other char beside ESCAPE or DELIM_START/STOP-combo
         // write unescaped escape chars
         writeUnescapedEscapeChars(escapeCounter, buffer);
         buffer.append(curChar);
     }
 
     /**
      * Writes "{}" to the specified result array at the specified position and returns the resulting position.
      */
     // Profiling showed this method is important to log4j performance. Modify with care!
     // 18 bytes (allows immediate JVM inlining: < 35 bytes) LOG4J2-1096
     private static void writeDelimPair(final StringBuilder buffer) {
         buffer.append(DELIM_START);
         buffer.append(DELIM_STOP);
     }
 
     /**
      * Returns {@code true} if the specified parameter is odd.
      */
     // Profiling showed this method is important to log4j performance. Modify with care!
     // 11 bytes (allows immediate JVM inlining: < 35 bytes) LOG4J2-1096
     private static boolean isOdd(final int number) {
         return (number & 1) == 1;
     }
 
     /**
      * Writes a '\' char to the specified result array (starting at the specified position) for each <em>pair</em> of
      * '\' escape chars encountered in the message format and returns the resulting position.
      */
     // Profiling showed this method is important to log4j performance. Modify with care!
     // 11 bytes (allows immediate JVM inlining: < 35 bytes) LOG4J2-1096
     private static void writeEscapedEscapeChars(final int escapeCounter, final StringBuilder buffer) {
         final int escapedEscapes = escapeCounter >> 1; // divide by two
         writeUnescapedEscapeChars(escapedEscapes, buffer);
     }
 
     /**
      * Writes the specified number of '\' chars to the specified result array (starting at the specified position) and
      * returns the resulting position.
      */
     // Profiling showed this method is important to log4j performance. Modify with care!
     // 20 bytes (allows immediate JVM inlining: < 35 bytes) LOG4J2-1096
     private static void writeUnescapedEscapeChars(int escapeCounter, final StringBuilder buffer) {
         while (escapeCounter > 0) {
             buffer.append(ESCAPE_CHAR);
             escapeCounter--;
         }
     }
 
     /**
      * Appends the argument at the specified argument index (or, if no such argument exists, the "{}" delimiter pair) to
      * the specified result char array at the specified position and returns the resulting position.
      */
     // Profiling showed this method is important to log4j performance. Modify with care!
     // 25 bytes (allows immediate JVM inlining: < 35 bytes) LOG4J2-1096
     private static void writeArgOrDelimPair(final Object[] arguments, final int argCount, final int currentArgument,
             final StringBuilder buffer) {
         if (currentArgument < argCount) {
             recursiveDeepToString(arguments[currentArgument], buffer, null);
         } else {
             writeDelimPair(buffer);
         }
     }
 
     /**
      * This method performs a deep toString of the given Object.
      * Primitive arrays are converted using their respective Arrays.toString methods while
      * special handling is implemented for "container types", i.e. Object[], Map and Collection because those could
      * contain themselves.
      * <p>
      * It should be noted that neither AbstractMap.toString() nor AbstractCollection.toString() implement such a
      * behavior. They only check if the container is directly contained in itself, but not if a contained container
      * contains the original one. Because of that, Arrays.toString(Object[]) isn't safe either.
      * Confusing? Just read the last paragraph again and check the respective toString() implementation.
      * </p>
      * <p>
      * This means, in effect, that logging would produce a usable output even if an ordinary System.out.println(o)
      * would produce a relatively hard-to-debug StackOverflowError.
      * </p>
      * @param o The object.
      * @return The String representation.
      */
     static String deepToString(final Object o) {
         if (o == null) {
             return null;
         }
         // Check special types to avoid unnecessary StringBuilder usage
         if (o instanceof String) {
             return (String) o;
         }
         if (o instanceof Integer) {
             return Integer.toString((Integer) o);
         }
         if (o instanceof Long) {
             return Long.toString((Long) o);
         }
         if (o instanceof Double) {
             return Double.toString((Double) o);
         }
         if (o instanceof Boolean) {
             return Boolean.toString((Boolean) o);
         }
         if (o instanceof Character) {
             return Character.toString((Character) o);
         }
         if (o instanceof Short) {
             return Short.toString((Short) o);
         }
         if (o instanceof Float) {
             return Float.toString((Float) o);
         }
         if (o instanceof Byte) {
             return Byte.toString((Byte) o);
         }
         final StringBuilder str = new StringBuilder();
         recursiveDeepToString(o, str, null);
         return str.toString();
     }
 
     /**
      * This method performs a deep toString of the given Object.
      * Primitive arrays are converted using their respective Arrays.toString methods while
      * special handling is implemented for "container types", i.e. Object[], Map and Collection because those could
      * contain themselves.
      * <p>
      * dejaVu is used in case of those container types to prevent an endless recursion.
      * </p>
      * <p>
      * It should be noted that neither AbstractMap.toString() nor AbstractCollection.toString() implement such a
      * behavior.
      * They only check if the container is directly contained in itself, but not if a contained container contains the
      * original one. Because of that, Arrays.toString(Object[]) isn't safe either.
      * Confusing? Just read the last paragraph again and check the respective toString() implementation.
      * </p>
      * <p>
      * This means, in effect, that logging would produce a usable output even if an ordinary System.out.println(o)
      * would produce a relatively hard-to-debug StackOverflowError.
      * </p>
      *
      * @param o      the Object to convert into a String
      * @param str    the StringBuilder that o will be appended to
      * @param dejaVu a list of container identities that were already used.
      */
     static void recursiveDeepToString(final Object o, final StringBuilder str, final Set<String> dejaVu) {
         if (appendSpecialTypes(o, str)) {
             return;
         }
         if (isMaybeRecursive(o)) {
             appendPotentiallyRecursiveValue(o, str, dejaVu);
         } else {
             tryObjectToString(o, str);
         }
     }
 
     private static boolean appendSpecialTypes(final Object o, final StringBuilder str) {
         return StringBuilders.appendSpecificTypes(str, o) || appendDate(o, str);
     }
 
     private static boolean appendDate(final Object o, final StringBuilder str) {
         if (!(o instanceof Date)) {
             return false;
         }
         final Date date = (Date) o;
         final SimpleDateFormat format = getSimpleDateFormat();
         str.append(format.format(date));
         return true;
     }
 
     private static SimpleDateFormat getSimpleDateFormat() {
         SimpleDateFormat result = threadLocalSimpleDateFormat.get();
         if (result == null) {
             result = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ");
             threadLocalSimpleDateFormat.set(result);
         }
         return result;
     }
 
     /**
      * Returns {@code true} if the specified object is an array, a Map or a Collection.
      */
     private static boolean isMaybeRecursive(final Object o) {
         return o.getClass().isArray() || o instanceof Map || o instanceof Collection;
     }
 
     private static void appendPotentiallyRecursiveValue(final Object o, final StringBuilder str,
             final Set<String> dejaVu) {
         final Class<?> oClass = o.getClass();
         if (oClass.isArray()) {
             appendArray(o, str, dejaVu, oClass);
         } else if (o instanceof Map) {
             appendMap(o, str, dejaVu);
         } else if (o instanceof Collection) {
             appendCollection(o, str, dejaVu);
         }
     }
 
     private static void appendArray(final Object o, final StringBuilder str, Set<String> dejaVu,
             final Class<?> oClass) {
         if (oClass == byte[].class) {
             str.append(Arrays.toString((byte[]) o));
         } else if (oClass == short[].class) {
             str.append(Arrays.toString((short[]) o));
         } else if (oClass == int[].class) {
             str.append(Arrays.toString((int[]) o));
         } else if (oClass == long[].class) {
             str.append(Arrays.toString((long[]) o));
         } else if (oClass == float[].class) {
             str.append(Arrays.toString((float[]) o));
         } else if (oClass == double[].class) {
             str.append(Arrays.toString((double[]) o));
         } else if (oClass == boolean[].class) {
             str.append(Arrays.toString((boolean[]) o));
         } else if (oClass == char[].class) {
             str.append(Arrays.toString((char[]) o));
         } else {
             if (dejaVu == null) {
                 dejaVu = new HashSet<>();
             }
             // special handling of container Object[]
             final String id = identityToString(o);
             if (dejaVu.contains(id)) {
                 str.append(RECURSION_PREFIX).append(id).append(RECURSION_SUFFIX);
             } else {
                 dejaVu.add(id);
                 final Object[] oArray = (Object[]) o;
                 str.append('[');
                 boolean first = true;
                 for (final Object current : oArray) {
                     if (first) {
                         first = false;
                     } else {
                         str.append(", ");
                     }
                     recursiveDeepToString(current, str, new HashSet<>(dejaVu));
                 }
                 str.append(']');
             }
             //str.append(Arrays.deepToString((Object[]) o));
         }
     }
 
     private static void appendMap(final Object o, final StringBuilder str, Set<String> dejaVu) {
         // special handling of container Map
         if (dejaVu == null) {
             dejaVu = new HashSet<>();
         }
         final String id = identityToString(o);
         if (dejaVu.contains(id)) {
             str.append(RECURSION_PREFIX).append(id).append(RECURSION_SUFFIX);
         } else {
             dejaVu.add(id);
             final Map<?, ?> oMap = (Map<?, ?>) o;
             str.append('{');
             boolean isFirst = true;
             for (final Object o1 : oMap.entrySet()) {
                 final Map.Entry<?, ?> current = (Map.Entry<?, ?>) o1;
                 if (isFirst) {
                     isFirst = false;
                 } else {
                     str.append(", ");
                 }
                 final Object key = current.getKey();
                 final Object value = current.getValue();
                 recursiveDeepToString(key, str, new HashSet<>(dejaVu));
                 str.append('=');
                 recursiveDeepToString(value, str, new HashSet<>(dejaVu));
             }
             str.append('}');
         }
     }
 
     private static void appendCollection(final Object o, final StringBuilder str, Set<String> dejaVu) {
         // special handling of container Collection
         if (dejaVu == null) {
             dejaVu = new HashSet<>();
         }
         final String id = identityToString(o);
         if (dejaVu.contains(id)) {
             str.append(RECURSION_PREFIX).append(id).append(RECURSION_SUFFIX);
         } else {
             dejaVu.add(id);
             final Collection<?> oCol = (Collection<?>) o;
             str.append('[');
             boolean isFirst = true;
             for (final Object anOCol : oCol) {
                 if (isFirst) {
                     isFirst = false;
                 } else {
                     str.append(", ");
                 }
                 recursiveDeepToString(anOCol, str, new HashSet<>(dejaVu));
             }
             str.append(']');
         }
     }
 
     private static void tryObjectToString(final Object o, final StringBuilder str) {
         // it's just some other Object, we can only use toString().
         try {
             str.append(o.toString());
         } catch (final Throwable t) {
             handleErrorInObjectToString(o, str, t);
         }
     }
 
     private static void handleErrorInObjectToString(final Object o, final StringBuilder str, final Throwable t) {
         str.append(ERROR_PREFIX);
         str.append(identityToString(o));
         str.append(ERROR_SEPARATOR);
         final String msg = t.getMessage();
         final String className = t.getClass().getName();
         str.append(className);
         if (!className.equals(msg)) {
             str.append(ERROR_MSG_SEPARATOR);
             str.append(msg);
         }
         str.append(ERROR_SUFFIX);
     }
 
     /**
      * This method returns the same as if Object.toString() would not have been
      * overridden in obj.
      * <p>
      * Note that this isn't 100% secure as collisions can always happen with hash codes.
      * </p>
      * <p>
      * Copied from Object.hashCode():
      * </p>
      * <blockquote>
      * As much as is reasonably practical, the hashCode method defined by
      * class {@code Object} does return distinct integers for distinct
      * objects. (This is typically implemented by converting the internal
      * address of the object into an integer, but this implementation
      * technique is not required by the Java&#8482; programming language.)
      * </blockquote>
      *
      * @param obj the Object that is to be converted into an identity string.
      * @return the identity string as also defined in Object.toString()
      */
     static String identityToString(final Object obj) {
         if (obj == null) {
             return null;
         }
         return obj.getClass().getName() + '@' + Integer.toHexString(System.identityHashCode(obj));
     }
 
 }