/**

  * Copyright 2010 The Kuali Foundation Licensed under the

  * Educational Community 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.osedu.org/licenses/ECL-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.kuali.student.common.util;

 import java.util.HashSet;

 import java.util.Map;

 import java.util.Set;

 public class MessageUtils {

     /**

      * Interpolates a message based on values contained in the data map, assuming message is formatted using a ${key} syntax.

      * 

      * @param message

      *            the message to be interpolated

      * @param data

      *            Map<String, String> containing the data to be used for interpolation

      * @return the interpolated message

      */

     public static String interpolate(String message, String... data) {

         if (message != null) {

             for (int i = 0; i < data.length; i++) {

                 message = message.replaceAll("\\$\\{" + i + "\\}", "" + escape(data[i]));

             }

         }

         return message;

     }

     /**

      * Interpolates a message based on parameter index, assuming message is formatted using a ${0}..${n} syntax

      * 

      * @param message

      *            the message to be interpolated

      * @param data

      *            varargs to be used for interpolation

      * @return the interpolated message

      */

     public static String interpolate(String message, Map<String, Object> data) {

         if (message != null && data != null) {

             Set<String> fields = findFields(message);

             for (String s : fields) {

                     if(data.get(s) != null){

                             message = message.replaceAll("\\$\\{" + s + "\\}", "" + escape(data.get(s).toString()));

                     }

             }

         }

         return message;

     }

     /**

      * Interpolates a message which requires only a single property replacement.

      * 

      * @param message

      * @param parameter

      * @param value

      * @return the interpolated message

      */

     public static String interpolate(String message, String parameter, Object value){

             message = message.replaceAll("\\$\\{" + parameter + "\\}", "" + escape(value.toString()));

             return message;

     }

     /**

      * Adds an escape to all characters requiring an escape.

      * 

      * @param input

      * @return the input string with characters escaped.

      */

     private static String escape(String input) {

         char[] toEscape = {'\\', '$', '.', '*', '+', '?', '|', '(', ')', '[', ']', '{', '}'};

         for (char c : toEscape) {

             input = input.replaceAll("\\" + c, "\\\\\\" + c);

         }

         return input;

     }

     /**

      * Returns a Set<String> of all interpolation targets (fields) within a String.

      * 

      * @param input

      *            the String from which to extract the interpolation targets

      * @return Set<String> containing the field names of the interpolation targets

      */

     public static Set<String> findFields(String input) {

         Set<String> result = new HashSet<String>();

         int begin = input.indexOf("${");

         while (begin != -1) {

             int end = input.indexOf("}", begin);

             result.add(input.substring(begin + 2, end));

             begin = input.indexOf("${", end);

         }

         return result;

     }

 }