package net.csksoft.TigerBox;

import java.io.IOException;
import java.io.StringReader;
import java.util.Hashtable;
import java.util.Vector;

import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.*;

import org.eclipse.swt.custom.StyleRange;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;

/*
 *  CSK 2004 - 2007
 *  Same chgs has been made to support Tiger Language
 *  www.csksoft.net
 */
/*******************************************************************************
* Copyright (c) 2000, 2003 IBM Corporation and others. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at [url]http://www.eclipse.org/legal/epl-v10.html[/url]
* 
* Contributors: IBM Corporation - initial API and implementation
******************************************************************************/

public class TigerLineStyler implements LineStyleListener {
	JavaScanner scanner = new JavaScanner();
	int[] tokenColors;
	Color[] colors;
	Vector blockComments = new Vector();

	public static final int EOF= -1;
	public static final int EOL= 10;

	public static final int WORD=		0;
	public static final int WHITE=		1;
	public static final int KEY=			2;
	public static final int COMMENT=		3;	
	public static final int STRING=		5;
	public static final int OTHER=		6;
	public static final int NUMBER=		7;

	public static final int MAXIMUM_TOKEN= 8;

public TigerLineStyler() {
	initializeColors();
	scanner = new JavaScanner();
}

Color getColor(int type) {
	if (type < 0 || type >= tokenColors.length) {
		return null;
	}
	return colors[tokenColors[type]];
}

boolean inBlockComment(int start, int end) {
	for (int i=0; i<blockComments.size(); i++) {
		int[] offsets = (int[])blockComments.elementAt(i);
		// start of comment in the line
		if ((offsets[0] >= start) && (offsets[0] <= end)) return true;
		// end of comment in the line
		if ((offsets[1] >= start) && (offsets[1] <= end)) return true;
		if ((offsets[0] <= start) && (offsets[1] >= end)) return true;
	}
	return false;
}

void initializeColors() {
	 Display display = Display.getDefault();
     colors = new Color[] { new Color(display, new RGB(0, 0, 0)), // black
                 new Color(display, new RGB(63, 127, 95)), // green
                 new Color(display, new RGB(127, 0, 85)), // drak red
                 new Color(display, new RGB(0, 0, 255)) // blue
     };
     tokenColors = new int[MAXIMUM_TOKEN];
     tokenColors[WORD] = 0;
     tokenColors[WHITE] = 0;
     tokenColors[KEY] = 3;
     tokenColors[COMMENT] = 1;
     tokenColors[STRING] = 2;
     tokenColors[OTHER] = 0;
     tokenColors[NUMBER] = 0;
}

void disposeColors() {
	for (int i=0;i<colors.length;i++) {
		colors[i].dispose();
	}
}

/**
 * Event.detail			line start offset (input)	
 * Event.text 			line text (input)
 * LineStyleEvent.styles 	Enumeration of StyleRanges, need to be in order. (output)
 * LineStyleEvent.background 	line background color (output)
 */
public void lineGetStyle(LineStyleEvent event) {
	this.parseBlockComments(((StyledText )event.getSource()).getText());
	Vector styles = new Vector();
	int token;
	StyleRange lastStyle;
	// If the line is part of a block comment, create one style for the entire line.
	if (inBlockComment(event.lineOffset, event.lineOffset + event.lineText.length())) {
		styles.addElement(new StyleRange(event.lineOffset, event.lineText.length(), getColor(COMMENT), null));
		event.styles = new StyleRange[styles.size()];
		styles.copyInto(event.styles);
		return;
	}
	Color defaultFgColor = ((Control)event.widget).getForeground();
	scanner.setRange(event.lineText);
	token = scanner.nextToken();
	while (token != EOF) {
		if (token == OTHER) {
			// do nothing for non-colored tokens
		} else if (token != WHITE) {
			Color color = getColor(token);
			// Only create a style if the token color is different than the 
			// widget's default foreground color and the token's style is not 
			// bold.  Keywords are bolded.
			if ((!color.equals(defaultFgColor)) || (token == KEY)) {
				StyleRange style = new StyleRange(scanner.getStartOffset() + event.lineOffset, scanner.getLength(), color, null);
				if (token == KEY) {
					style.fontStyle = SWT.BOLD;
				}
				if (styles.isEmpty()) {
					styles.addElement(style);
				} else {
					// Merge similar styles.  Doing so will improve performance.
					lastStyle = (StyleRange)styles.lastElement();
					if (lastStyle.similarTo(style) && (lastStyle.start + lastStyle.length == style.start)) {
						lastStyle.length += style.length;
					} else {
						styles.addElement(style); 
					}
				} 
			} 
		} else if ((!styles.isEmpty()) && ((lastStyle=(StyleRange)styles.lastElement()).fontStyle == SWT.BOLD)) {
			int start = scanner.getStartOffset() + event.lineOffset;
			lastStyle = (StyleRange)styles.lastElement();
			// A font style of SWT.BOLD implies that the last style
			// represents a java keyword.
			if (lastStyle.start + lastStyle.length == start) {
				// Have the white space take on the style before it to 
				// minimize the number of style ranges created and the
				// number of font style changes during rendering.
				lastStyle.length += scanner.getLength();
			}
		} 
		token= scanner.nextToken();
	}
	event.styles = new StyleRange[styles.size()];
	styles.copyInto(event.styles);
}
public void parseBlockComments(String text) {
	blockComments = new Vector();
	StringReader buffer = new StringReader(text);
	int ch;
	boolean blkComment = false;
	int cnt = 0;
	int cmt_cnt = 0;
	int[] offsets = new int[2];
	boolean done = false;
	
	try {
	while (!done) {
		switch (ch = buffer.read()) {
			case -1 : {
				if (blkComment) {
					offsets[1] = cnt;
					blockComments.addElement(offsets);
				}
				done = true;
				break;
			}
			case '/' : {
				ch = buffer.read();
				if (ch == '*') {
					offsets = new int[2];
					offsets[0] = cnt;
					cmt_cnt++;
					blkComment = true;
					cnt++;	
				} else {
					cnt++;
				}						
				cnt++;
				break;
			}
			case '*' : {
				if (blkComment) {
					ch = buffer.read();
					cnt++;
					if (ch == '/') {
						cmt_cnt--;
						if (cmt_cnt<=0)
						{
						blkComment = false;	
						offsets[1] = cnt;
						blockComments.addElement(offsets);
						cmt_cnt=0;
						}
					}
				}
				cnt++;	
				break;
			}
			default : {
				cnt++;				
				break;
			}
		}
	}		
	} catch(IOException e) {
		// ignore errors
	}

     }

     /**
      * A simple fuzzy scanner for Java
      */
     public class JavaScanner {

           protected Hashtable fgKeys = null;

           protected StringBuffer fBuffer = new StringBuffer();

           protected String fDoc;

           protected int fPos;

           protected int fEnd;

           protected int fStartToken;

           protected boolean fEofSeen = false;
           
           protected int comment_loop = 0;
     
           private String[] fgKeywords = { "array", "if", "then",
            "else", "while", "for", "to", "do", "let", "in",
            "end", "of", "break", "nil", "function", "var", "type",
            "int", "string", "true", "false" };
           
        
           
           public JavaScanner() {
                 initialize();
           }

           /**
            * Returns the ending location of the current token in the document.
            */
           public final int getLength() {
                 return fPos - fStartToken;
           }

           /**
            * Initialize the lookup table.
            */
           void initialize() {
                 fgKeys = new Hashtable();
                 Integer k = new Integer(KEY);
                 for (int i = 0; i < fgKeywords.length; i++)
                       fgKeys.put(fgKeywords[i], k);
           }

           /**
            * Returns the starting location of the current token in the document.
            */
           public final int getStartOffset() {
                 return fStartToken;
           }

           /**
            * Returns the next lexical token in the document.
            */
           public int nextToken() {
                 int c;
                 fStartToken = fPos;
                 while (true) {
                	   
                       switch (c = read()) {
                       case EOF:
                    	    
                             return EOF;
                      

                       case '"': // string
                             string: for (;;) {
                                   c = read();
                                   switch (c) {
                                   case '"':
                                         return STRING;
                                   case EOF:
                                         unread(c);
                                         return STRING;
                                   case '\\':
                                         c = read();
                                         break;
                                   }
                             }

                       case '0':
                       case '1':
                       case '2':
                       case '3':
                       case '4':
                       case '5':
                       case '6':
                       case '7':
                       case '8':
                       case '9':
                             do {
                                   c = read();
                             } while (Character.isDigit((char) c));
                             unread(c);
                             return NUMBER;
                       default:
                             if (Character.isWhitespace((char) c)) {
                                   do {
                                         c = read();
                                   } while (Character.isWhitespace((char) c));
                                   unread(c);
                                   return WHITE;
                             }
                             if (Character.isJavaIdentifierStart((char) c)) {
                                   fBuffer.setLength(0);
                                   do {
                                         fBuffer.append((char) c);
                                         c = read();
                                   } while (Character.isJavaIdentifierPart((char) c));
                                   unread(c);
                                   Integer i = (Integer) fgKeys.get(fBuffer.toString());
                                   if (i != null)
                                         return i.intValue();
                                   return WORD;
                             }
                             return OTHER;
                       }
                 }
           }

           /**
            * Returns next character.
            */
           protected int read() {
                 if (fPos <= fEnd) {
                       return fDoc.charAt(fPos++);
                 }
                 return EOF;
           }

           public void setRange(String text) {
                 fDoc = text;
                 fPos = 0;
                 fEnd = fDoc.length() - 1;
           }

           protected void unread(int c) {
                 if (c != EOF)
                       fPos--;
           }
     }

}