/*
    * Copyright (c) 2003, Henri Yandell
    * All rights reserved.
    * 
    * Redistribution and use in source and binary forms, with or 
    * without modification, are permitted provided that the 
    * following conditions are met:
    * 
    * + Redistributions of source code must retain the above copyright notice, 
   *   this list of conditions and the following disclaimer.
   * 
   * + Redistributions in binary form must reproduce the above copyright notice, 
   *   this list of conditions and the following disclaimer in the documentation 
   *   and/or other materials provided with the distribution.
   * 
   * + Neither the name of XmlWriter nor the names of its contributors 
   *   may be used to endorse or promote products derived from this software 
   *   without specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
   * POSSIBILITY OF SUCH DAMAGE.
   */
  package com.generationjava.io.xml;
  
  /***
   * XML helping static methods.
   *
   * @author <a href="mailto:bayard@apache.org">Henri Yandell</a>
   * @version 1.0
   */
  public final class XmlUtils {
  
      public static String escapeXml(String str) {
          str = str.replaceAll("&","&amp;");
          str = str.replaceAll("<","&lt;");
          str = str.replaceAll(">","&gt;");
          str = str.replaceAll("\"","&quot;");
          str = str.replaceAll("'","&apos;");
          return str;
      }
  
      public static String unescapeXml(String str) {
          str = str.replaceAll("&amp;","&");
          str = str.replaceAll("&lt;","<");
          str = str.replaceAll("&gt;",">");
          str = str.replaceAll("&quot;","\"");
          str = str.replaceAll("&apos;","'");
          return str;
      }
  
      /***
       * Remove any xml tags from a String.
       * Same as HtmlW's method.
       */
      public static String removeXml(String str) {
          int sz = str.length();
          StringBuffer buffer = new StringBuffer(sz);
          boolean inString = false;
          boolean inTag = false;
          for(int i=0; i<sz; i++) {
              char ch = str.charAt(i);
              if(ch == '<') {
                  inTag = true;
              } else
              if(ch == '>') {
                  inTag = false;
                  continue;
              }
              if(!inTag) {
                  buffer.append(ch);
              }
          }
          return buffer.toString();
      }
  
      public static String getContent(String tag, String text) {
          int idx = XmlUtils.getIndexOpeningTag(tag, text);
          if(idx == -1) {
              return "";
          }
          text = text.substring(idx);
          int end = XmlUtils.getIndexClosingTag(tag, text);
          idx = text.indexOf('>');
          if(idx == -1) {
              return "";
          }
          return text.substring(idx+1, end);
      }
  
      public static int getIndexOpeningTag(String tag, String text) {
         return getIndexOpeningTag(tag, text, 0);
     }
     private static int getIndexOpeningTag(String tag, String text, int start) {
         // consider whitespace?
         int idx = text.indexOf("<"+tag, start);
         if(idx == -1) {
             return -1;
         }
         char next = text.charAt(idx+1+tag.length());
         if( (next == '>') || Character.isWhitespace(next) ) {
             return idx;
         } else {
             return getIndexOpeningTag(tag, text, idx+1);
         }
     }
 
     // Pass in "para" and a string that starts with 
     // <para> and it will return the index of the matching </para>
     // It assumes well-formed xml. Or well enough.
     public static int getIndexClosingTag(String tag, String text) {
         return getIndexClosingTag(tag, text, 0);
     }
     public static int getIndexClosingTag(String tag, String text, int start) {
         String open = "<"+tag;
         String close = "</"+tag+">";
 //        System.err.println("OPEN: "+open);
 //        System.err.println("CLOSE: "+close);
         int closeSz = close.length();
         int nextCloseIdx = text.indexOf(close, start);
 //        System.err.println("first close: "+nextCloseIdx);
         if(nextCloseIdx == -1) {
             return -1;
         }
         int count = XmlUtils.countMatches(text.substring(start, nextCloseIdx), open);
 //        System.err.println("count: "+count);
         if(count == 0) {
             return -1;  // tag is never opened
         }
         int expected = 1;
         while(count != expected) {
             nextCloseIdx = text.indexOf(close, nextCloseIdx+closeSz);
             if(nextCloseIdx == -1) {
                 return -1;
             }
             count = XmlUtils.countMatches(text.substring(start, nextCloseIdx), open);
             expected++;
         }
         return nextCloseIdx;
     }
 
     public static String getAttribute(String attribute, String text) {
         return getAttribute(attribute, text, 0);
     }
     public static String getAttribute(String attribute, String text, int idx) {
          int close = text.indexOf(">", idx);
          int attrIdx = text.indexOf(attribute+"=\"", idx);
          if(attrIdx == -1) {
              return null;
          }
          if(attrIdx > close) {
              return null;
          }
          int attrStartIdx = attrIdx + attribute.length() + 2;
          int attrCloseIdx = text.indexOf("\"", attrStartIdx);
          if(attrCloseIdx > close) {
              return null;
          }
          return unescapeXml(text.substring(attrStartIdx, attrCloseIdx));
     }
 
     // Taken from Commons Lang StringUtils 2.x
     private static int countMatches(String str, String sub) {
         if (str == null || str.length() == 0 || sub == null || sub.length() == 0) {
             return 0;
         }
         int count = 0;
         int idx = 0;
         while ((idx = str.indexOf(sub, idx)) != -1) {
             count++;
             idx += sub.length();
         }
         return count;
     }
 
 
 }