/*
    * 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.myfaces.shared.util;
  
  /**
   * This class contains utility methods to detect special cases to be handled on "script" or
   * "style" tags by HtmlResponseWriterImpl.
   */
  public class CommentUtils
  {
      public static final String INLINE_SCRIPT_COMMENT = "//";
      public static final String START_SCRIPT_COMMENT = "/*";
      public static final String END_SCRIPT_COMMENT = "*/";
      public static final String CDATA_SIMPLE_START = "<![CDATA[";
      public static final String CDATA_SIMPLE_END = "]]>";
      public static final String COMMENT_SIMPLE_START = "<!--";
      public static final String COMMENT_SIMPLE_END = "-->";
  
      public static boolean isStartMatchWithCommentedCDATA(String trimmedContent)
      {
          if (trimmedContent.startsWith(START_SCRIPT_COMMENT))
          {
              int offset = 2;
              while (trimmedContent.charAt(offset) <= ' ')
              {
                  offset++;
              }
              if (trimmedContent.startsWith(CDATA_SIMPLE_START, offset))
              {
                  return true;
              }
          }
          return false;
      }
      
      public static boolean isEndMatchWithCommentedCDATA(String trimmedContent)
      {
          if (trimmedContent.endsWith(END_SCRIPT_COMMENT))
          {
              int offset = trimmedContent.length()-3;
              while (trimmedContent.charAt(offset) <= ' ')
              {
                  offset--;
              }
              // CDATA_SIMPLE_END.length() = 3
              // So, -3 +1 = -2
              if (trimmedContent.startsWith(CDATA_SIMPLE_END, offset - 2))
              {
                  return true;
              }
          }
          return false;
      }
  
      public static boolean isEndMatchtWithInlineCommentedXmlCommentTag(String trimmedContent)
      {
          if (trimmedContent.endsWith(COMMENT_SIMPLE_END))
          {
              int offset = trimmedContent.length()-4;
              while (trimmedContent.charAt(offset) <= ' ' &&
                      trimmedContent.charAt(offset) != '\n')
              {
                  offset--;
              }
              // INLINE_SCRIPT_COMMENT.length() = 2
              // So, -2 +1 = -1
              if (trimmedContent.startsWith(INLINE_SCRIPT_COMMENT, offset - 1))
              {
                  return true;
              }
          }
          return false;        
      }
      
      public static boolean isStartMatchWithInlineCommentedCDATA(String trimmedContent)
      {
          if (trimmedContent.startsWith(INLINE_SCRIPT_COMMENT))
          {
              int offset = 2;
              while (trimmedContent.charAt(offset) <= ' ' &&
                      trimmedContent.charAt(offset) != '\n')
              {
                  offset++;
             }
             if (trimmedContent.startsWith(CDATA_SIMPLE_START, offset))
             {
                 return true;
             }
         }
         return false;
     }
     
     public static boolean isEndMatchWithInlineCommentedCDATA(String trimmedContent)
     {
         if (trimmedContent.endsWith(CDATA_SIMPLE_END))
         {
             int offset = trimmedContent.length()- 4;
             while (trimmedContent.charAt(offset) <= ' ' &&
                     trimmedContent.charAt(offset) != '\n')
             {
                 offset--;
             }
             // INLINE_SCRIPT_COMMENT.length() = 2
             // So, -2 +1 = -1
             if (trimmedContent.startsWith(INLINE_SCRIPT_COMMENT, offset - 1))
             {
                 return true;
             }
         }
         return false;
     }
 }