/*
 * SimplyHTML, a word processor based on Java, HTML and CSS
 * Copyright (C) 2002 Ulrich Hilger
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

package com.lightdev.app.shtm;

import java.io.Writer;
import java.io.IOException;
import javax.swing.text.html.StyleSheet;
import javax.swing.text.Style;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyleContext;
import javax.swing.text.AttributeSet;
import java.util.Enumeration;

/**
 * A writer for writing a <code>StyleSheet</code> into a CSS file.
 *
 * @author Ulrich Hilger
 * @author Light Development
 * @author <a href="http://www.lightdev.com">http://www.lightdev.com</a>
 * @author <a href="mailto:info@lightdev.com">info@lightdev.com</a>
 * @author published under the terms and conditions of the
 *      GNU General Public License,
 *      for details see file gpl.txt in the distribution
 *      package of this software
 * 
 */

class CSSWriter {

  /** spaces for indent */
  private char[] indentChars;

  /** new line character sequence */
  private String newLine = System.getProperty("line.separator");

  /** the writer to write to */
  private Writer writer;

  /** the style sheet to write */
  private StyleSheet styleSheet;

  /** indent length */
  private int indentLen;

  /**
   * construct a new CSSWriter
   *
   * @param writer  the writer to write to
   * @param styleSheet  the StyleSheet to write
   */
  public CSSWriter(Writer writer, StyleSheet styleSheet) {
    this.writer = writer;
    this.styleSheet = styleSheet;
  }

  /** write the style sheet to the given writer */
  public void write() throws IOException {
    Enumeration rules = styleSheet.getStyleNames();
    while(rules.hasMoreElements()) {
      writeRule((String) rules.nextElement());
      try {
        Thread.currentThread();
		Thread.sleep(0, 1);
      } catch(Exception e) { }
    }
  }

  /**
   * write out a rule with a given name
   *
   * <p>Takes the style with the given name from the style sheet passed in the
   * constructor and writes it to the writer passed in the constructor.</p>.
   *
   * @param ruleName  the name of the rule to write out
   *
   * @exception IOException if i/o fails
   */
  private void writeRule(String ruleName) throws IOException {
    writeRule(ruleName, styleSheet.getStyle(ruleName));
  }

  /**
   * write out a rule with a given name and style
   *
   * <p>Takes the style passed in paramter 'rule' and writes it under
   * the given name to the writer passed in the constructor.</p>.

   * @param ruleName  the name of the rule to write out
   * @apram rule  the style to write out
   *
   * @exception IOException if i/o fails
   */
  public void writeRule(String ruleName, AttributeSet rule) throws IOException { 
    //System.out.println("CSSWriter writeRule ruleName=" + ruleName);
    indentLen = ruleName.length() + 3;
    if(!ruleName.equalsIgnoreCase(StyleContext.DEFAULT_STYLE)) {
      writer.write(ruleName);
      writer.write(" { ");
      writeStyle(rule);
      writer.write(newLine);
    }
  }

  /**
   * write a given style
   *
   * <p>A style is an AttributeSet which can have other
   * AttributeSets in the value field of one of its Attributes.
   * Therefore this is recursively called whenever an Attribute
   * contains another AttributeSet.</p>
   *
   * @param style the <code>Style</code> to write
   *
   * @return true, if the style was closed in this run of recursion,
   *      false if not
   */
  private boolean writeStyle(AttributeSet style) throws IOException {
    boolean closed = false;
    Enumeration names = style.getAttributeNames();
    Object value;
    Object key;
    int count = 0;
    while(names.hasMoreElements()) {
      key = names.nextElement();
      value = style.getAttribute(key);
      if( (!key.equals(StyleConstants.NameAttribute)) &&
          (!key.equals(StyleConstants.ResolveAttribute)) )
      {
        if(count > 0) {
          writer.write(newLine);
          indent(indentLen);
        }
        else {
          count++;
        }
        writer.write(key.toString());
        writer.write(":");
        writer.write(value.toString());
        writer.write(";");
      }
      else {
        if(key.equals(StyleConstants.ResolveAttribute)) {
          closed = writeStyle((Style) value);
        }
      }
    }
    if(!closed) {
      writer.write(" }");
      writer.write(newLine);
      closed = true;
    }
    return closed;
  }

  /**
   * indent by a given number of characters
   *
   * @param len the number of characters to indent
   */
  private void indent(int len) throws IOException {
    if(indentChars == null || len > indentChars.length) {
      indentChars = new char[len];
      for (int i = 0; i < len; i++) {
        indentChars[i] = ' ';
      }
    }
    writer.write(indentChars, 0, len);
  }
}