/*
 * SyntaxUtilities.java - Utility functions used by syntax colorizing
 * Copyright (C) 1999 Slava Pestov
 *
 * You may use and modify this package for any purpose. Redistribution is
 * permitted, in both source and binary form, provided that this notice
 * remains intact in all source distributions of this package.
 */

package processing.app.syntax;

import javax.swing.text.*;
import java.awt.*;


/**
 * Class with several utility functions used by jEdit's syntax colorizing
 * subsystem.
 *
 * @author Slava Pestov
 * @version $Id$
 */
public class SyntaxUtilities
{
  /**
   * Checks if a subregion of a <code>Segment</code> is equal to a
   * string.
   * @param ignoreCase True if case should be ignored, false otherwise
   * @param text The segment
   * @param offset The offset into the segment
   * @param match The string to match
   */
  public static boolean regionMatches(boolean ignoreCase, Segment text,
                                      int offset, String match)
  {
    int length = offset + match.length();
    char[] textArray = text.array;
    if(length > text.offset + text.count)
      return false;
    for(int i = offset, j = 0; i < length; i++, j++)
      {
        char c1 = textArray[i];
        char c2 = match.charAt(j);
        if(ignoreCase)
          {
            c1 = Character.toUpperCase(c1);
            c2 = Character.toUpperCase(c2);
          }
        if(c1 != c2)
          return false;
      }
    return true;
  }


  /**
   * Checks if a subregion of a <code>Segment</code> is equal to a
   * character array.
   * @param ignoreCase True if case should be ignored, false otherwise
   * @param text The segment
   * @param offset The offset into the segment
   * @param match The character array to match
   */
  public static boolean regionMatches(boolean ignoreCase, Segment text,
                                      int offset, char[] match)
  {
    int length = offset + match.length;
    char[] textArray = text.array;
    if(length > text.offset + text.count)
      return false;
    for(int i = offset, j = 0; i < length; i++, j++)
      {
        char c1 = textArray[i];
        char c2 = match[j];
        if(ignoreCase)
          {
            c1 = Character.toUpperCase(c1);
            c2 = Character.toUpperCase(c2);
          }
        if(c1 != c2)
          return false;
      }
    return true;
  }


  /**
   * Returns the default style table. This can be passed to the
   * <code>setStyles()</code> method of <code>SyntaxDocument</code>
   * to use the default syntax styles.
   */
  public static SyntaxStyle[] getDefaultSyntaxStyles()
  {
    SyntaxStyle[] styles = new SyntaxStyle[Token.ID_COUNT];

    styles[Token.COMMENT1] = new SyntaxStyle(Color.black,true,false);
    styles[Token.COMMENT2] = new SyntaxStyle(new Color(0x990033),true,false);
    styles[Token.KEYWORD1] = new SyntaxStyle(Color.black,false,true);
    styles[Token.KEYWORD2] = new SyntaxStyle(Color.magenta,false,false);
    styles[Token.KEYWORD3] = new SyntaxStyle(new Color(0x009600),false,false);
    styles[Token.LITERAL1] = new SyntaxStyle(new Color(0x650099),false,false);
    styles[Token.LITERAL2] = new SyntaxStyle(new Color(0x650099),false,true);
    styles[Token.LABEL] = new SyntaxStyle(new Color(0x990033),false,true);
    styles[Token.OPERATOR] = new SyntaxStyle(Color.black,false,true);
    styles[Token.INVALID] = new SyntaxStyle(Color.red,false,true);

    return styles;
  }


  /**
   * Paints the specified line onto the graphics context. Note that this
   * method munges the offset and count values of the segment.
   * @param line The line segment
   * @param tokens The token list for the line
   * @param styles The syntax style list
   * @param expander The tab expander used to determine tab stops. May
   * be null
   * @param gfx The graphics context
   * @param x The x co-ordinate
   * @param y The y co-ordinate
   * @return The x co-ordinate, plus the width of the painted string
   */
  public static int paintSyntaxLine(Segment line, Token tokens,
                                    SyntaxStyle[] styles,
                                    TabExpander expander, Graphics gfx,
                                    int x, int y)
  {
    Font defaultFont = gfx.getFont();
    Color defaultColor = gfx.getColor();

    int offset = 0;
    for(;;)
      {
        byte id = tokens.id;
        if(id == Token.END)
          break;

        int length = tokens.length;
        if(id == Token.NULL)
          {
            if(!defaultColor.equals(gfx.getColor()))
              gfx.setColor(defaultColor);
            if(!defaultFont.equals(gfx.getFont()))
              gfx.setFont(defaultFont);
          }
        else
          styles[id].setGraphicsFlags(gfx,defaultFont);

        line.count = length;
        x = Utilities.drawTabbedText(line,x,y,gfx,expander,0);
        line.offset += length;
        offset += length;

        tokens = tokens.next;
      }

    return x;
  }

  // private members
  private SyntaxUtilities() {}
}