/*
    * 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.io.IOException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.text.Format;
  import java.text.MessageFormat;
  import java.util.Arrays;
  import java.util.regex.Pattern;
  
  /**
   * Handles messages that contain a format String. Dynamically determines if the format conforms to
   * MessageFormat or String.format and if not then uses ParameterizedMessage to format.
   */
  public class FormattedMessage implements Message {
  
      private static final long serialVersionUID = -665975803997290697L;
      private static final int HASHVAL = 31;
      private static final String FORMAT_SPECIFIER = "%(\\d+\\$)?([-#+ 0,(\\<]*)?(\\d+)?(\\.\\d+)?([tT])?([a-zA-Z%])";
      private static final Pattern MSG_PATTERN = Pattern.compile(FORMAT_SPECIFIER);
  
      private String messagePattern;
      private transient Object[] argArray;
      private String[] stringArgs;
      private transient String formattedMessage;
      private final Throwable throwable;
      private Message message;
  
      public FormattedMessage(final String messagePattern, final Object[] arguments, final Throwable throwable) {
          this.messagePattern = messagePattern;
          this.argArray = arguments;
          this.throwable = throwable;
      }
  
      public FormattedMessage(final String messagePattern, final Object[] arguments) {
          this.messagePattern = messagePattern;
          this.argArray = arguments;
          this.throwable = null;
      }
  
      /**
       * Constructor with a pattern and a single parameter.
       * @param messagePattern The message pattern.
       * @param arg The parameter.
       */
      public FormattedMessage(final String messagePattern, final Object arg) {
          this.messagePattern = messagePattern;
          this.argArray = new Object[] {arg};
          this.throwable = null;
      }
  
      /**
       * Constructor with a pattern and two parameters.
       * @param messagePattern The message pattern.
       * @param arg1 The first parameter.
       * @param arg2 The second parameter.
       */
      public FormattedMessage(final String messagePattern, final Object arg1, final Object arg2) {
          this(messagePattern, new Object[]{arg1, arg2});
      }
  
  
      /**
       * Returns the formatted message.
       * @return the formatted message.
       */
      @Override
      public String getFormattedMessage() {
          if (formattedMessage == null) {
              if (message == null) {
                  message = getMessage(messagePattern, argArray, throwable);
              }
              formattedMessage = message.getFormattedMessage();
          }
          return formattedMessage;
      }
  
      /**
       * Returns the message pattern.
       * @return the message pattern.
       */
      @Override
      public String getFormat() {
         return messagePattern;
     }
 
     /**
      * Returns the message parameters.
      * @return the message parameters.
      */
     @Override
     public Object[] getParameters() {
         if (argArray != null) {
             return argArray;
         }
         return stringArgs;
     }
 
     protected Message getMessage(final String msgPattern, final Object[] args, final Throwable throwable) {
         try {
             final MessageFormat format = new MessageFormat(msgPattern);
             final Format[] formats = format.getFormats();
             if (formats != null && formats.length > 0) {
                 return new MessageFormatMessage(msgPattern, args);
             }
         } catch (final Exception ex) {
             // Obviously, the message is not a proper pattern for MessageFormat.
         }
         try {
             if (MSG_PATTERN.matcher(msgPattern).find()) {
                 return new StringFormattedMessage(msgPattern, args);
             }
         } catch (final Exception ex) {
             // Also not properly formatted.
         }
         return new ParameterizedMessage(msgPattern, args, throwable);
     }
 
     @Override
     public boolean equals(final Object o) {
         if (this == o) {
             return true;
         }
         if (o == null || getClass() != o.getClass()) {
             return false;
         }
 
         final FormattedMessage that = (FormattedMessage) o;
 
         if (messagePattern != null ? !messagePattern.equals(that.messagePattern) : that.messagePattern != null) {
             return false;
         }
         if (!Arrays.equals(stringArgs, that.stringArgs)) {
             return false;
         }
 
         return true;
     }
 
     @Override
     public int hashCode() {
         int result = messagePattern != null ? messagePattern.hashCode() : 0;
         result = HASHVAL * result + (stringArgs != null ? Arrays.hashCode(stringArgs) : 0);
         return result;
     }
 
 
     @Override
     public String toString() {
         return "FormattedMessage[messagePattern=" + messagePattern + ", args=" +
             Arrays.toString(argArray) + ']';
     }
 
     private void writeObject(final ObjectOutputStream out) throws IOException {
         out.defaultWriteObject();
         getFormattedMessage();
         out.writeUTF(formattedMessage);
         out.writeUTF(messagePattern);
         out.writeInt(argArray.length);
         stringArgs = new String[argArray.length];
         int i = 0;
         for (final Object obj : argArray) {
             stringArgs[i] = obj.toString();
             ++i;
         }
     }
 
     private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
         in.defaultReadObject();
         formattedMessage = in.readUTF();
         messagePattern = in.readUTF();
         final int length = in.readInt();
         stringArgs = new String[length];
         for (int i = 0; i < length; ++i) {
             stringArgs[i] = in.readUTF();
         }
     }
 
     /**
      * Always returns null.
      *
      * @return null
      */
     @Override
     public Throwable getThrowable() {
         if (throwable != null) {
             return throwable;
         }
         if (message == null) {
             message = getMessage(messagePattern, argArray, null);
         }
         return message.getThrowable();
     }
 }