/**

  * 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.creadur.whisker.out.velocity;

 import java.io.BufferedReader;

 import java.io.IOException;

 import java.io.StringReader;

 import org.apache.commons.lang3.StringUtils;

 /**

  * Manages indentation level.

  */

 public class Indentation {

     /**

      * Creates appropriate indentation, padding with spaces.

      * @param indentation not null

      * @param source not null

      * @return appropriate indentation, not null

      * @throws IOException when source cannot be read

      */

     public final String indent(

             final int indentation, final Object source) throws IOException {

         return this.indent(indentation, source, ' ');

     }

     /**

      * Creates appropriate indentation.

      * @param indentation not null

      * @param source not null

      * @param pad padding

      * @return appropriate indentation, not null

      * @throws IOException when source cannot be read

      */

     public final String indent(

             final int indentation, final Object source, final char pad)

                 throws IOException {

         final String result;

         if (source == null) {

             result = "";

         } else {

             result = prefixLine(source, StringUtils.repeat(pad, indentation));

         }

         return result;

     }

     /**

      * Creates appropriate indentation.

      * @param source not null

      * @param prefix not null

      * @return appropriate indentation, not null

      * @throws IOException when source cannot be read

      */

     private String prefixLine(final Object source, final String prefix)

             throws IOException {

         final String result;

         final StringBuilder builder = new StringBuilder();

         final BufferedReader lineReader =

             new BufferedReader(new StringReader(source.toString()));

         String line = lineReader.readLine();

         while (line != null) {

             builder.append('\n').append(prefix).append(line);

             line = lineReader.readLine();

         }

         result = builder.toString();

         return result;

     }

 }