/*
    * Copyright 2007-2013 smartics, Kronseder & Reiner GmbH
    *
    * Licensed 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 de.smartics.exceptions.report.utils;
  
  import static de.smartics.exceptions.report.utils.StringFunction.indexOfFirstWhiteSpace;
  
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  
  import org.apache.commons.lang.StringUtils;
  
  import com.thoughtworks.qdox.model.DocletTag;
  import com.thoughtworks.qdox.model.JavaAnnotatedElement;
  import com.thoughtworks.qdox.model.impl.DefaultDocletTag;
  
  import de.smartics.util.lang.Arg;
  
  /**
   * Parses the Javadoc body and returns the tags and text fragments as an
   * iterator.
   */
  public final class InlineJavadocTags implements Iterable<DocletTag>
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    /**
     * The identifier of doclets that only contain text.
     */
    public static final String TEXT_DOCLET_NAME = "{text}";
  
    // --- members --------------------------------------------------------------
  
    /**
     * The annotated element whose Javadoc comment is to be parsed.
     */
    private final JavaAnnotatedElement element;
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Default constructor.
     *
     * @param element the annotated element whose Javadoc comment is to be parsed.
     * @throws NullPointerException if {@code element} is <code>null</code>.
     */
    public InlineJavadocTags(final JavaAnnotatedElement element)
      throws NullPointerException
    {
      this.element = Arg.checkNotNull("element", element);
    }
  
    // ****************************** Inner Classes *****************************
  
    // ********************************* Methods ********************************
  
    // --- init -----------------------------------------------------------------
  
    // --- get&set --------------------------------------------------------------
  
    // --- business -------------------------------------------------------------
  
    // CHECKSTYLE:OFF
    /**
     * Parses the Javadoc body and returns the tags and text fragments as an
     * iterator.
     *
     * @return the iterator over doclet tags and javadoc text.
     */
    @Override
    public Iterator<DocletTag> iterator()
    {
      final List<DocletTag> tags = new ArrayList<DocletTag>();
  
      final String comment = element.getComment();
      if (StringUtils.isBlank(comment))
      {
        return tags.iterator();
      }
  
      final int length = comment.length();
      final char[] commentArray = comment.toCharArray();
     final StringBuilder buffer = new StringBuilder(512);
     boolean inText = true;
     int lineNumber = 0;
     for (int i = 0; i < length; i++)
     {
       final char c = commentArray[i];
 
       if (inText)
       {
         if (c == '{')
         {
           if (commentArray[i + 1] == '@')
           {
             if (buffer.length() > 0)
             {
               final DocletTag textTag =
                   createTextTag(inText, buffer, lineNumber);
               tags.add(textTag);
               buffer.setLength(0);
             }
             i++;
             inText = false;
           }
           else
           {
             buffer.append(c);
           }
         }
         else
         {
           buffer.append(c);
         }
       }
       else
       {
         if (c == '}')
         {
           final DocletTag tag = createTag(buffer, lineNumber);
           tags.add(tag);
           buffer.setLength(0);
           inText = true;
         }
         else
         {
           buffer.append(c);
         }
       }
 
       if (c == '\n')
       {
         lineNumber++;
       }
     }
 
     if (buffer.length() > 0)
     {
       final DocletTag textTag = createTextTag(inText, buffer, lineNumber);
       tags.add(textTag);
     }
 
     return tags.iterator();
   }
   // CHECKSTYLE:ON
 
   private DocletTag createTextTag(final boolean inText,
       final StringBuilder buffer, final int lineNumber)
   {
     final String string = buffer.toString();
     final String value = inText ? string : "{@" + string;
 
     final DefaultDocletTag tag =
         new DefaultDocletTag(TEXT_DOCLET_NAME, value, element, lineNumber);
     return tag;
   }
 
   private DocletTag createTag(final StringBuilder buffer, final int lineNumber)
   {
     final int firstBlank = indexOfFirstWhiteSpace(buffer);
     final String name =
         firstBlank == -1 ? buffer.toString() : buffer
             .subSequence(0, firstBlank).toString();
     final String value =
         firstBlank != -1 && firstBlank + 1 < buffer.length() ? buffer
             .substring(firstBlank + 1).trim() : StringUtils.EMPTY;
     final DefaultDocletTag tag =
         new DefaultDocletTag(name, value, element, lineNumber);
     return tag;
   }
 
   /**
    * Checks if the given tag is a simple text element.
    *
    * @param tag the tag to test.
    * @return <code>true</code> if the tag is only a text, <code>false</code> if
    *         it is a doclet tag.
    * @throws NullPointerException if {@code tag} is <code>null</code>.
    */
   public static boolean isText(final DocletTag tag) throws NullPointerException
   {
     return TEXT_DOCLET_NAME.equals(tag.getName());
   }
 
   // --- object basics --------------------------------------------------------
 
 }