/*
    * HtmlFormatter.java -- HTML document pretty-printer
    * Copyright (C) 1999 Quiotix Corporation.  
    *
    * This program is free software; you can redistribute it and/or modify
    * it under the terms of the GNU General Public License, version 2, as 
    * published by the Free Software Foundation.  
    *
    * 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 (http://www.gnu.org/copyleft/gpl.txt)
   * for more details.
   */
  
  package com.quiotix.html.parser;
  
  import java.io.BufferedOutputStream;
  import java.io.FileInputStream;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.PrintWriter;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.Set;
  
  /**
   * HtmlFormatter is a Visitor which traverses an HtmlDocument, dumping the
   * contents of the document to a specified output stream.  It assumes that
   * the documents has been preprocessed by HtmlCollector (which matches up
   * beginning and end tags) and by HtmlScrubber (which formats tags in a
   * consistent way).  In particular, HtmlScrubber should be invoked with the
   * TRIM_SPACES option to remove trailing spaces, which can confuse the
   * formatting algorithm.
   * <p>
   * The right margin and indent increment can be specified as properties.
   * </p>
   * 
   * @author Brian Goetz, Quiotix
   * @see com.quiotix.html.parser.HtmlVisitor
   * @see com.quiotix.html.parser.HtmlCollector
   * @see com.quiotix.html.parser.HtmlScrubber
   */
  
  public class HtmlFormatter extends HtmlVisitor {
      protected MarginWriter out;
      protected int rightMargin = 80;
      protected int indentSize = 2;
      protected static Set tagsIndentBlock = new HashSet();
      protected static Set tagsNewlineBefore = new HashSet();
      protected static Set tagsPreformatted = new HashSet();
      protected static Set tagsTryMatch = new HashSet();
      protected static final String[] tagsIndentStrings
              = {"TABLE", "TR", "TD", "TH", "FORM", "HTML", "HEAD", "BODY", "SELECT", "OL", "UL", "LI"};
      protected static final String[] tagsNewlineBeforeStrings
              = {"P", "H1", "H2", "H3", "H4", "H5", "H6", "BR"};
      protected static final String[] tagsPreformattedStrings
              = {"PRE", "SCRIPT", "STYLE"};
      protected static final String[] tagsTryMatchStrings
              = {"A", "TD", "TH", "TR", "I", "B", "EM", "FONT", "TT", "UL", "OL", "LI"};
  
      static {
          for (int i = 0; i < tagsIndentStrings.length; i++)
              tagsIndentBlock.add(tagsIndentStrings[i]);
          for (int i = 0; i < tagsNewlineBeforeStrings.length; i++)
              tagsNewlineBefore.add(tagsNewlineBeforeStrings[i]);
          for (int i = 0; i < tagsPreformattedStrings.length; i++)
              tagsPreformatted.add(tagsPreformattedStrings[i]);
          for (int i = 0; i < tagsTryMatchStrings.length; i++)
              tagsTryMatch.add(tagsTryMatchStrings[i]);
      }
      protected TagBlockRenderer blockRenderer = new TagBlockRenderer();
      protected HtmlDocument.HtmlElement previousElement;
      protected boolean inPreBlock;
  
      /** Constructor. */
      public HtmlFormatter(OutputStream os) throws Exception {
          out = new MarginWriter(new PrintWriter(new BufferedOutputStream(os)));
          out.setRightMargin(rightMargin);
      }
  
      /**
       * @param margin the right margin column to wrap at
       */
      public void setRightMargin(int margin) {
          rightMargin = margin;
          out.setRightMargin(rightMargin);
      }
  
      /**
       * @param indent the number of spaces to indent by
       */
      public void setIndent(int indent) {
          indentSize = indent;
      }
  
      public void visit(HtmlDocument.TagBlock block) {
          boolean indent;
          boolean preformat;
         int wasMargin = 0;
 
         if (tagsTryMatch.contains(block.startTag.tagName.toUpperCase())) {
             blockRenderer.start();
             blockRenderer.setTargetWidth(out.getRightMargin() - out.getLeftMargin());
             blockRenderer.visit(block);
             blockRenderer.finish();
             if (!blockRenderer.hasBlownTarget()) {
                 out.printAutoWrap(blockRenderer.getString());
                 previousElement = block.endTag;
                 return;
             } 
 
         }
 
         // Only will get here if we've failed the try-block test
         indent = tagsIndentBlock.contains(block.startTag.tagName.toUpperCase());
         preformat = tagsPreformatted.contains(block.startTag.tagName.toUpperCase());
         if (preformat) {
             inPreBlock = true;
             visit(block.startTag);
             wasMargin = out.getLeftMargin();
             out.setLeftMargin(0);
             visit(block.body);
             out.setLeftMargin(wasMargin);
             visit(block.endTag);
         } else if (indent) {
             out.printlnSoft();
             visit(block.startTag);
             out.printlnSoft();
             out.setLeftMargin(out.getLeftMargin() + indentSize);
             visit(block.body);
             out.setLeftMargin(out.getLeftMargin() - indentSize);
             out.printlnSoft();
             visit(block.endTag);
             out.printlnSoft();
             inPreBlock = false;
         } else {
             visit(block.startTag);
             visit(block.body);
             visit(block.endTag);
         }
     }
 
     public void visit(HtmlDocument.Tag t) {
         String s = t.toString();
         int hanging;
 
         if (tagsNewlineBefore.contains(t.tagName.toUpperCase())
                 || out.getCurPosition() + s.length() > out.getRightMargin())
             out.printlnSoft();
 
         out.print("<" + t.tagName);
         hanging = t.tagName.length() + 1;
         for (Iterator it = t.attributeList.attributes.iterator(); it.hasNext();) {
             HtmlDocument.Attribute a = (HtmlDocument.Attribute) it.next();
             out.printAutoWrap(" " + a.toString(), hanging);
         }
         if (t.emptyTag) out.print("/");
         out.print(">");
         previousElement = t;
     }
 
     public void visit(HtmlDocument.EndTag t) {
         out.printAutoWrap(t.toString());
         if (tagsNewlineBefore.contains(t.tagName.toUpperCase())) {
             out.printlnSoft();
             out.println();
         }
         previousElement = t;
     }
 
     public void visit(HtmlDocument.Comment c) {
         out.print(c.toString());
         previousElement = c;
     }
 
     public void visit(HtmlDocument.Text t) {
         if (inPreBlock)
             out.print(t.text);
         else {
             int start = 0;
             while (start < t.text.length()) {
                 int index = t.text.indexOf(' ', start) + 1;
                 if (index == 0)
                     index = t.text.length();
                 out.printAutoWrap(t.text.substring(start, index));
                 start = index;
             }
         }
         previousElement = t;
     }
 
     public void visit(HtmlDocument.Newline n) {
         if (inPreBlock)
             out.println();
         else if (previousElement instanceof HtmlDocument.Tag
                 || previousElement instanceof HtmlDocument.EndTag
                 || previousElement instanceof HtmlDocument.Comment
                 || previousElement instanceof HtmlDocument.Newline)
             out.printlnSoft();
         else if (previousElement instanceof HtmlDocument.Text)
             out.print(" ");
         previousElement = n;
     }
 
     public void start() {
         previousElement = null;
         inPreBlock = false;
     }
 
     public void finish() {
         out.flush();
     }
 
     /**
      * Runnable.
      */
     public static void main(String[] args) throws Exception {
         InputStream r = new FileInputStream(args[0]);
         HtmlDocument document;
 
         try {
             document = new HtmlParser(r).HtmlDocument();
             document.accept(new HtmlCollector());
             document.accept(new HtmlScrubber(HtmlScrubber.DEFAULT_OPTIONS
                     | HtmlScrubber.TRIM_SPACES));
             document.accept(new HtmlFormatter(System.out));
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             r.close();
         }
     }
 }
 
 
 /**
  * Utility class, used by HtmlFormatter, which adds some word-wrapping
  * and hanging indent functionality to a PrintWriter.
  */
 
 class MarginWriter {
     protected int tabStop;
     protected int curPosition;
     protected int leftMargin;
     protected int rightMargin;
     protected java.io.PrintWriter out;
     protected char[] spaces = new char[256];
 
     /** Constructor. */
     MarginWriter(java.io.PrintWriter out) {
         this.out = out;
         for (int i = 0; i < spaces.length; i++)
             spaces[i] = ' ';
     }
 
     void flush() {
         out.flush();
     }
 
     void close() {
         out.close();
     }
 
     void print(String s) {
         if (curPosition == 0 && leftMargin > 0) {
             out.write(spaces, 0, leftMargin);
             curPosition = leftMargin;
         }
         out.print(s);
         curPosition += s.length();
     }
 
     void printAutoWrap(String s) {
         if (curPosition > leftMargin
                 && curPosition + s.length() > rightMargin)
             println();
         print(s);
     }
 
     void printAutoWrap(String s, int hanging) {
         if (curPosition > leftMargin
                 && curPosition + s.length() > rightMargin) {
             println();
             out.write(spaces, 0, hanging + leftMargin);
             curPosition = leftMargin + hanging;
         };
         print(s);
     }
 
     void println() {
         curPosition = 0;
         out.println();
     }
 
     void printlnSoft() {
         if (curPosition > 0)
             println();
     }
 
     void setLeftMargin(int leftMargin) {
         this.leftMargin = leftMargin;
     }
 
     int getLeftMargin() {
         return leftMargin;
     }
 
     void setRightMargin(int rightMargin) {
         this.rightMargin = rightMargin;
     }
 
     int getRightMargin() {
         return rightMargin;
     }
 
     int getCurPosition() {
         return (curPosition == 0 ? leftMargin : curPosition);
     }
 }
 
 /**
  * Utility class, used by HtmlFormatter, which tentatively tries to format
  * the contents of an HtmlDocument.TagBlock to see if the entire block can
  * fit on the rest of the line.  If it cannot, it gives up and indicates
  * failure through the hasBlownTarget method; if it can, the contents can
  * be retrieved through the getString method.
  */
 
 class TagBlockRenderer extends HtmlVisitor {
     protected String s;
     protected boolean multiLine;
     protected boolean blownTarget;
     protected int targetWidth = 80;
 
     public void start() {
         s = "";
         multiLine = false;
         blownTarget = false;
     }
 
     public void finish() {
     }
 
     void setTargetWidth(int w) {
         targetWidth = w;
     }
 
     String getString() {
         return s;
     }
 
     boolean isMultiLine() {
         return multiLine;
     }
 
     boolean hasBlownTarget() {
         return blownTarget;
     }
 
     public void visit(HtmlDocument.Tag t) {
         if (s.length() < targetWidth)
             s += t.toString();
         else
             blownTarget = true;
     }
 
     public void visit(HtmlDocument.EndTag t) {
         if (s.length() < targetWidth)
             s += t.toString();
         else
             blownTarget = true;
     }
 
     public void visit(HtmlDocument.Comment c) {
         if (s.length() < targetWidth)
             s += c.toString();
         else
             blownTarget = true;
     }
 
     public void visit(HtmlDocument.Text t) {
         if (s.length() < targetWidth)
             s += t.toString();
         else
             blownTarget = true;
     }
 
     public void visit(HtmlDocument.Newline n) {
         multiLine = true;
         s += " ";
     }
 }