/**
 * SimpleTimeBarCanvas displays the time for the world map.<p>
 *
 * Copyright &copy; 1996-98 Martin Minow. All Rights Reserved.<p>
 *
 * Permission to use, copy, modify, and redistribute this software and its
 * documentation for personal, non-commercial use is hereby granted provided that
 * this copyright notice and appropriate documentation appears in all copies. This
 * software may not be distributed for fee or as part of commercial, "shareware,"
 * and/or not-for-profit endevors including, but not limited to, CD-ROM collections,
 * online databases, and subscription services without specific license.<p>
 *
 * @author <a href="mailto:minow@merrymeet.com">Martin Minow</a>
 * @version 1.1
 * Set tabs every 4 characters.
 */
// package Classes;

import java.util.*;
import java.awt.*;

/**
 * This must be installed centered, north, directly under SunriseCanvas.
 */
public class SimpleTimeBarCanvas extends Canvas
{
	protected SunriseCanvas		sunriseCanvas;
	protected Date					instant = new Date();
	protected double				theTimeAtGMT;

	/**
	 * Initialize the panel.
	 */
	public SimpleTimeBarCanvas(
			SunriseCanvas			sunriseCanvas
		)
	{
		this.sunriseCanvas	= sunriseCanvas;
	}
	public Dimension preferredSize()
	{
		/*
		 * The timebar is slightly wider than the world map it illustrates.
		 */
		FontMetrics		fontMetrics		= getFontMetrics(getFont());
		Dimension		d				= new Dimension(
					sunriseCanvas.size().width + fontMetrics.charWidth('0') * 10,
					fontMetrics.getHeight()
				);
		return (d);
	}
	public Dimension getPreferredSize()
	{
		return (preferredSize());
	}
	/**
	 * Draw the display.
	 * @param g		the current graphics context.
	 * Note: this presumes that the TimeBarCanvas is directly centered above or below
	 * the sunImageCanvas (the layout method will decide).
	 */
	public synchronized void paint(
			Graphics			g
		)
	{
		/*
		 * Delay display until the sunImageCanvas is initialized.
		 */
		if (sunriseCanvas.bounds() != null) {
			FontMetrics fontMetrics		= g.getFontMetrics();
			/*
			 * We need the width of the sunriseImage and it's left origin
			 * translated into the timeBar coordinates.
			 */
			instant							= sunriseCanvas.getDate();
			theTimeAtGMT					=
				((double) (instant.getTime() % 86400000L)) / 3600000.0;
			Rectangle	worldMapBounds		= sunriseCanvas.bounds();
			int			worldMapWidth		= worldMapBounds.width;
			int			stepSize			= worldMapWidth / 6;
			int			origin				= worldMapBounds.x - this.bounds().x;
			if (fontMetrics.stringWidth(" 00:00") < stepSize) {
			   origin -= (fontMetrics.stringWidth("00:00") / 2);
				/*
				 * The <= in the for loop is intentional: we need to traverse
				 * the loop an extra time to avoid a fencepost error.
				 */
				for (int xPixel = 0; xPixel <= worldMapWidth; xPixel += stepSize) {
					double	timeAtXPixel	= xPixelToTime(xPixel);
					g.drawString(
						timeString(timeAtXPixel),
						xPixel + origin,
						fontMetrics.getAscent()
					);
				}
			}
		}
	}
	/**
	 * Convert a pixel offset in the range 0 .. worldMapRect.width to the time at this
	 * location (using the current time at this.instant and the observer's timezone).
	 * @param xPixel	The pixel offset to convert.
	 * @return the time (hour.fraction) at this pixel offset.
	 */
	private double xPixelToTime(
			int					xPixel
		)
	{
		try {
			int			worldMapWidth		= sunriseCanvas.bounds().width;
			/*
			 * Convert xPixel to a time value referenced to GMT. Note that
			 * xPixel == 0 -> -0.5, xPixel == worldMapRect.width / 2 -> 0.0;
			 */
			double xFraction	= ((double) (xPixel - worldMapWidth / 2))
								/ ((double) worldMapWidth);
			double now			= theTimeAtGMT + (xFraction * 24.0);
			while (now >= 24.0)
				now -= 24.0;
			while (now < 0.0)
				now += 24.0;
			return (now);
		}
		catch (Exception e) {	/* Handle no image present yet case	*/
			return (0.0);
		}
	}
	/*
	 * Convert a time (in the range 0.0 .. 24.0) to a time string.
	 */
	public static String timeString(
			double				value
		)
	{
		int		hour		= (int) Math.floor(value);
		value				= (value - (double) hour) * 60.0;
		int		minute		= (int) (value + 0.5);
		if (minute >= 60) {
			++hour;
			minute -= 60;
		}
		if (hour >= 24) {
			hour -= 24;
		}
		StringBuffer	result = new StringBuffer();
		if (hour < 10) {
			result.append('0');
		}
		result.append(new Integer(hour).toString());
		result.append(':');
		if (minute < 10) {
			result.append('0');
		}
		result.append(new Integer(minute).toString());
		return (result.toString());
	}
}