/**
 * CodeViewer.java
 * CoolServlets.com
 * July 17, 2000
 *
 * Copyright (C) 2000 CoolServlets.com
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 1) Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * 2) 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.
 * 3) Neither the name CoolServlets.com 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 COOLSERVLETS.COM 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 COOLSERVLETS.COM 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.Yasna.codeviewer;

import java.util.*;

/**
 * A class that syntax highlights Java code into html.
 * <p>
 * A CodeViewer object is created and then keeps state as
 * lines are passed in. Each line passed in as java text, is returned as syntax
 * highlighted html text.
 * <p>
 * Users of the class can set how the java code will be highlighted with
 * setter methods.
 * <p>
 * Only valid java lines should be passed in since the object maintains
 * state and may not handle illegal code gracefully.
 * <p>
 * The actual system is implemented as a series of filters that deal with
 * specific portions of the java code. The filters are as follows:
 * <p>
 * <pre>
 *  htmlFilter
 *     |__
 *        multiLineCommentFilter
 *           |___
 *                inlineCommentFilter
 *                   |___
 *                        stringFilter
 *                           |__
 *                               keywordFilter
 * </pre>
 *
 */
public class CodeViewer {

    //private static HashMap reservedWords = new HashMap(80); // >= Java2 only (also, not thread-safe)
    private static Hashtable reservedWords = new Hashtable(80); // < Java2 (thread-safe)
    private boolean inMultiLineComment = false;
    private String backgroundColor = "#ffffff";
    private String commentStart = "<font color=\"#aa0000\"><i>";
    private String commentEnd = "</font></i>";
    private String stringStart = "<font color=\"#000099\">";
    private String stringEnd = "</font>";
    private String reservedWordStart = "<b>";
    private String reservedWordEnd = "</b>";

    /**
     * Load all keywords at class loading time.
     */
    static {
        loadKeywords();
    }

    /**
     * Gets the html for the start of a comment block.
     */
    public String getCommentStart() {
        return commentStart;
    }

    /**
     * Sets the html for the start of a comment block.
     */
    public void setCommentStart(String commentStart) {
        this.commentStart = commentStart;
    }

    /**
     * Gets the html for the end of a comment block.
     */
    public String getCommentEnd() {
        return commentEnd;
    }

    /**
     * Sets the html for the end of a comment block.
     */
    public void setCommentEnd(String commentEnd) {
        this.commentEnd = commentEnd;
    }

    /**
     * Gets the html for the start of a String.
     */
    public String getStringStart() {
        return stringStart;
    }

    /**
     * Sets the html for the start of a String.
     */
    public void setStringStart(String stringStart) {
        this.stringStart = stringStart;
    }

    /**
     * Gets the html for the end of a String.
     */
    public String getStringEnd() {
        return stringEnd;
    }

    /**
     * Sets the html for the end of a String.
     */
    public void setStringEnd(String stringEnd) {
        this.stringEnd = stringEnd;
    }

    /**
     * Gets the html for the start of a reserved word.
     */
    public String getReservedWordStart() {
        return reservedWordStart;
    }

    /**
     * Sets the html for the start of a reserved word.
     */
    public void setReservedWordStart(String reservedWordStart) {
        this.reservedWordStart = reservedWordStart;
    }

    /**
     * Gets the html for the end of a reserved word.
     */
    public String getReservedWordEnd() {
        return reservedWordEnd;
    }

    /**
     * Sets the html for the end of a reserved word.
     */
    public void setReservedWordEnd(String reservedWordEnd) {
        this.reservedWordEnd = reservedWordEnd;
    }

    /**
     * Passes off each line to the first filter.
     * @param   line    The line of Java code to be highlighted.
     */
    public String syntaxHighlight( String line ) {
       return htmlFilter(line);
    }

    /*
     * Filter html tags that appear in the java source into more benign text
     * that won't disrupt the output.
     */
    private String htmlFilter( String line ) {
        if( line == null || line.equals("") ) {
            return "";
        }
        // replace ampersands with HTML escape sequence for ampersand;
        line = replace(line, "&", "&#38;");

        // replace \" sequences with HTML escape sequences;
        line = replace(line, "\\\"", "&#92;&#34");

        // replace the \\ with HTML escape sequences. fixes a problem when
        // backslashes preceed quotes.
        line = replace(line, "\\\\", "&#92;&#92;" );

        // replace less-than signs which might be confused
        // by HTML as tag angle-brackets;
        line = replace(line, "<", "&#60;");
        // replace greater-than signs which might be confused
        // by HTML as tag angle-brackets;
        line = replace(line, ">", "&#62;");

        return multiLineCommentFilter(line);
    }

    /*
     * Filter out multiLine comments. State is kept with a private boolean
     * variable.
     */
    private String multiLineCommentFilter(String line) {
        if (line == null || line.equals("")) {
            return "";
        }
        StringBuffer buf = new StringBuffer();
        int index;
        //First, check for the end of a multi-line comment.
        if (inMultiLineComment && (index = line.indexOf("*/")) > -1 && !isInsideString(line,index)) {
            inMultiLineComment = false;
            buf.append(line.substring(0,index));
            buf.append("*/").append(commentEnd);
            if (line.length() > index+2) {
                buf.append(inlineCommentFilter(line.substring(index+2)));
            }
            return buf.toString();
        }
        //If there was no end detected and we're currently in a multi-line
        //comment, we don't want to do anymore work, so return line.
        else if (inMultiLineComment) {
            return line;
        }
        //We're not currently in a comment, so check to see if the start