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/*
 * 10/28/2004
 *
 * DefaultToken.java - The default token used in syntax highlighting.
 * 
 * This library is distributed under a modified BSD license.  See the included
 * RSyntaxTextArea.License.txt file for details.
 */
package org.fife.ui.rsyntaxtextarea;

import java.awt.Color;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import javax.swing.text.Segment;
import javax.swing.text.TabExpander;
import javax.swing.text.Utilities;


/**
 * The default token used in the org.fife.ui.rsyntaxtextarea syntax
 * package.  This token type paints itself as you would expect, and properly
 * accounts for rendering hints (anti-aliasing and fractional font metrics).
 *
 * The current implementation paints as follows:
 * 

 *   The first tab, if any, is found in the token.
 *   All characters up to that tab, if it exists, are painted as a
 *       group.  If no tab was found, all characters in the token are
 *       painted.
 *   If a tab was found, its width is calculated and it is painted.
 *   Repeat until all characters are painted.
 * 
 * This method allows for rendering hints to be honored, since all possible
 * characters are painted in a group.  However, adjacent tokens will not have
 * their "touching" characters rendered with rendering hints.
 *
 * A problem with this implementation is that FontMetrics.charsWidth() is still
 * used to calculate the width of a group of chars painted.  Thus, the group of
 * characters will be painted with the rendering hints specified, but the
 * following tab (or group of characters if the current group was the end of a
 * token) will not necessarily be painted at the proper x-coordinate (as
 * FontMetrics.charsWidth() returns an int and not a
 * float).  The way around this would be to calculate the token's
 * width in such a way that a float is returned (Font.getStringBounds()?).
 *
 * @author Robert Futrell
 * @version 0.5
 * @see Token
 * @see VisibleWhitespaceToken
 */
public class DefaultToken extends Token {


	/**
	 * Creates a "null token."  The token itself is not null; rather, it
	 * signifies that it is the last token in a linked list of tokens and
	 * that it is not part of a "multi-line token."
	 */
	public DefaultToken() {
		super();
	}


	/**
	 * Constructor.
	 *
	 * @param line The segment from which to get the token.
	 * @param beg The first character's position in line.
	 * @param end The last character's position in line.
	 * @param startOffset The offset into the document at which this
	 *        token begins.
	 * @param type A token type listed as "generic" above.
	 */
	public DefaultToken(final Segment line, final int beg, final int end,
							final int startOffset, final int type) {
		this(line.array, beg,end, startOffset, type);
	}


	/**
	 * Constructor.
	 *
	 * @param line The segment from which to get the token.
	 * @param beg The first character's position in line.
	 * @param end The last character's position in line.
	 * @param startOffset The offset into the document at which this
	 *        token begins.
	 * @param type A token type listed as "generic" above.
	 */
	public DefaultToken(final char[] line, final int beg, final int end,
							final int startOffset, final int type) {
		super(line, beg,end, startOffset, type);
	}


	/**
	 * Determines the offset into this token list (i.e., into the
	 * document) that covers pixel location x if the token list
	 * starts at pixel location x0.
	 * This method will return the document position "closest" to the
	 * x-coordinate (i.e., if they click on the "right-half" of the
	 * w in awe, the caret will be placed in
	 * between the w and e; similarly, clicking on
	 * the left-half places the caret between the a and
	 * w).  This makes it useful for methods such as
	 * viewToModel found in javax.swing.text.View
	 * subclasses.
	 *
	 * @param textArea The text area from which the token list was derived.
	 * @param e How to expand tabs.
	 * @param x0 The pixel x-location that is the beginning of
	 *        tokenList.
	 * @param x The pixel-position for which you want to get the corresponding
	 *        offset.
	 * @return The position (in the document, NOT into the token list!) that
	 *         covers the pixel location.  If tokenList is
	 *         null or has type Token.NULL, then
	 *         -1= x)
			return offset;

		float currX = x0;	// x-coordinate of current char.
		float nextX = x0;	// x-coordinate of next char.
		float stableX = x0;	// Cached ending x-coord. of last tab or token.
		Token token = this;
		int last = offset;
		FontMetrics fm = null;

		while (token!=null && token.isPaintable()) {

			fm = textArea.getFontMetricsForTokenType(token.type);
			char[] text = token.text;
			int start = token.textOffset;
			int end = start + token.textCount;

			for (int i=start; i=currX && x3
	 * here returns the width of the "whi" portion of the token.

	 *
	 * @param numChars The number of characters for which to get the width.
	 * @param textArea The text area in which this token is being painted.
	 * @param e How to expand tabs.  This value cannot be null.
	 * @param x0 The pixel-location at which this token begins.  This is needed
	 *        because of tabs.
	 * @return The width of the specified number of characters in this token.
	 * @see #getWidth
	 */
	public float getWidthUpTo(int numChars, RSyntaxTextArea textArea,
							TabExpander e, float x0) {
		float width = x0;
		FontMetrics fm = textArea.getFontMetricsForTokenType(type);
		if (fm!=null) {
			int w;
			int currentStart = textOffset;
			int endBefore = textOffset + numChars;
			for (int i=currentStart; i0)
						width += fm.charsWidth(text, currentStart, w);
					currentStart = i+1;
					width = e.nextTabStop(width, 0);
				}
			}
			// Most (non-whitespace) tokens will have characters at this
			// point to get the widths for, so we don't check for w>0 (mini-
			// optimization).
			w = endBefore-currentStart;
			width += fm.charsWidth(text, currentStart, w);
		}
		return width - x0;
	}


	/**
	 * Returns the bounding box for the specified document location.  The
	 * location must be in the specified token list.
	 *
	 * @param textArea The text area from which the token list was derived.
	 * @param e How to expand tabs.
	 * @param pos The position in the document for which to get the bounding
	 *        box in the view.
	 * @param x0 The pixel x-location that is the beginning of
	 *        tokenList.
	 * @param rect The rectangle in which we'll be returning the results.  This
	 *        object is reused to keep from frequent memory allocations.
	 * @return The bounding box for the specified position in the model.
	 */
	public Rectangle listOffsetToView(RSyntaxTextArea textArea, TabExpander e,
										int pos, int x0, Rectangle rect) {

		int stableX = x0;	// Cached ending x-coord. of last tab or token.
		Token token = this;
		FontMetrics fm = null;
		Segment s = new Segment();

		while (token!=null && token.isPaintable()) {

			fm = textArea.getFontMetricsForTokenType(token.type);
			if (fm==null) {
				return rect; // Don't return null as things'll error.
			}
			char[] text = token.text;
			int start = token.textOffset;
			int end = start + token.textCount;

			// If this token contains the position for which to get the
			// bounding box...
			if (token.containsPosition(pos)) {

				s.array = token.text;
				s.offset = token.textOffset;
				s.count = pos-token.offset;

				// Must use this (actually fm.charWidth()), and not
				// fm.charsWidth() for returned value to match up with where
				// text is actually painted on OS X!
				int w = Utilities.getTabbedTextWidth(s, fm, stableX, e,
													token.offset);
				rect.x = stableX + w;
				end = token.documentToToken(pos);

				if (text[end]=='\t') {
					rect.width = fm.charWidth(' ');
				}
				else {
					rect.width = fm.charWidth(text[end]);
				}

				return rect;

			}

			// If this token does not contain the position for which to get
			// the bounding box...
			else {
				s.array = token.text;
				s.offset = token.textOffset;
				s.count = token.textCount;
				stableX += Utilities.getTabbedTextWidth(s, fm, stableX, e,
														token.offset);
			}

			token = token.getNextToken();

		}

		// If we didn't find anything, we're at the end of the line.  Return
		// a width of 1 (so selection highlights don't extend way past line's
		// text).  A ConfigurableCaret will know to paint itself with a larger
		// width.
		rect.x = stableX;
		rect.width = 1;
		return rect;

	}


	/**
	 * Paints this token.
	 *
	 * @param g The graphics context in which to paint.
	 * @param x The x-coordinate at which to paint.
	 * @param y The y-coordinate at which to paint.
	 * @param host The text area this token is in.
	 * @param e How to expand tabs.
	 * @param clipStart The left boundary of the clip rectangle in which we're
	 *        painting.  This optimizes painting by allowing us to not paint
	 *        when this token is "to the left" of the clip rectangle.
	 * @return The x-coordinate representing the end of the painted text.
	 */
	public float paint(Graphics2D g, float x, float y, RSyntaxTextArea host,
								TabExpander e, float clipStart) {

		int origX = (int)x;
		int end = textOffset + textCount;
		float nextX = x;
		int flushLen = 0;
		int flushIndex = textOffset;
		Color fg = host.getForegroundForToken(this);
		Color bg = host.getBackgroundForTokenType(type);
		g.setFont(host.getFontForTokenType(type));
		FontMetrics fm = host.getFontMetricsForTokenType(type);

		for (int i=textOffset; i 0) {
						g.setColor(fg);
						g.drawChars(text, flushIndex, flushLen, (int)x,(int)y);
						flushLen = 0;
					}
					flushIndex = i + 1;
					x = nextX;
					break;
				default:
					flushLen += 1;
					break;
			}
		}

		nextX = x+fm.charsWidth(text, flushIndex,flushLen);

		if (flushLen>0 && nextX>=clipStart) {
			if (bg!=null) {
				paintBackground(x,y, nextX-x,fm.getHeight(),
								g, fm.getAscent(), host, bg);
			}
			g.setColor(fg);
			g.drawChars(text, flushIndex, flushLen, (int)x,(int)y);
		}

		if (host.getUnderlineForToken(this)) {
			g.setColor(fg);
			int y2 = (int)(y+1);
			g.drawLine(origX,y2, (int)nextX,y2);
		}

		return nextX;

	}


}