/***********************************************************************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others. All rights reserved. This program and the accompanying materials are made
 * available under the terms of the Common Public License v1.0 which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors: IBM Corporation - initial API and implementation
 **********************************************************************************************************************************/
package net.sourceforge.phpeclipse.wiki.editor.model;

import java.util.Stack;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;

public class WikipediaOutlineParser {

  private IDocument fDocument;

  /**
   * Next line to read.
   */
  private int fLine;

  private int fLineCount;

  public WikipediaSection parse(IDocument document) {
    try {
      fDocument = document;
      fLine = 0;
      fLineCount = fDocument.getNumberOfLines();
      return parseWikipediaText();
    } catch (BadLocationException e) {
      e.printStackTrace();
      return null;
    }
  }

  private WikipediaSection parseWikipediaText() throws BadLocationException {
    Stack stack = new Stack();
    char ch;
    WikipediaText wikiText = new WikipediaText();
    WikipediaSection section;
    //    int startOffset = -1;
    String textString;
    String headerString = null;
    char[] text;
    IRegion region = null;
    int headerStartOffset;
    int headerEndOffset;
    int headerLevelCounter;

    while (fLine < fLineCount) {
      region = fDocument.getLineInformation(fLine);
      textString = fDocument.get(region.getOffset(), region.getLength());
      text = textString.toCharArray();
      fLine++;

      headerStartOffset = 0;
      if (text.length >= 2 && text[headerStartOffset++] == '=') {
        headerEndOffset = text.length;
        while (headerEndOffset > 0 && Character.isWhitespace(text[--headerEndOffset])) {
          //
        }
        if (text[headerEndOffset] == '=') {
          // header section
          while (headerStartOffset < text.length && headerStartOffset < 6 && text[headerStartOffset++] == '=') {
            //
          }
          headerLevelCounter = 1;
          while (headerEndOffset > 0 && headerLevelCounter < headerStartOffset && text[--headerEndOffset] == '=') {
            headerLevelCounter++;
          }

          //          if (!stack.isEmpty()) {
          //            section = (WikipediaSection) stack.pop();
          //            section.setLength(region.getOffset() - section.getOffset() - 1);
          //            wikiText.add(section);
          //          }

          //          headerString = new String(text, headerStartOffset - 1, headerEndOffset - headerStartOffset + 2);
          //          stack.push(new WikipediaSection(wikiText, headerString, headerLevelCounter, region.getOffset(), 1));
          if (headerStartOffset > 0 && (headerEndOffset - headerStartOffset + 2 > 0)) {
            headerString = new String(text, headerStartOffset - 1, headerEndOffset - headerStartOffset + 2);
            addSection(wikiText, new WikipediaSection(wikiText, headerString, headerLevelCounter, region.getOffset(), 1), stack,
                region);

          }

        }
      }
    }
    if (!stack.isEmpty()) {
      reduceSection(wikiText, stack, region);
      //      section = (WikipediaSection) stack.pop();
      //      section.setLength(region.getOffset() - section.getOffset() - 1);
      //      wikiText.add(section);
    }
    return wikiText;
  }

  private void addSection(WikipediaSection wikiText, WikipediaSection currentSection, Stack stack, IRegion region) {
    int level = currentSection.getHeaderLevel();
    while (!stack.isEmpty()) {
      WikipediaSection section = (WikipediaSection) stack.peek();
      if (section.getHeaderLevel() < level) {
        currentSection.setParent(section);
        section.add(currentSection);
        stack.push(currentSection);
        return;
      } else { // if (section.getHeaderLevel() <= level) {
        stack.pop();
        section.setLength(region.getOffset() - section.getOffset() - 1);
      }
    }
    currentSection.setParent(wikiText);
    wikiText.add(currentSection);
    stack.push(currentSection);
  }

  private void reduceSection(WikipediaSection wikiText, Stack stack, IRegion region) {
    while (!stack.isEmpty()) {
      WikipediaSection section = (WikipediaSection) stack.peek();
      stack.pop();
      section.setLength(region.getOffset() - section.getOffset() - 1);
    }
  }
}