// ClockPanel.java -- Manages the appearance of the clock, and keeps track of
// the current time, and periodically checks to see if the alarm time has been
// reached.  This is not a robust implementation.  For example, by default the
// current time and alarm time are set to 12:00:00.
import javax.swing.*;       // for JPanel
import java.awt.*;          // for graphics
import java.awt.geom.*;     // for ellipse
import java.awt.event.*;    // for action listener

public class ClockPanel extends JPanel
{
  private static final int SIZE = 600;
  private static final int BORDER = 20;
  private static final int RADIUS = SIZE / 2 - BORDER;
  private static final int CENTER = SIZE / 2;
  private Ellipse2D.Double circle;
  private Line2D.Double [] hourMark;
  private Line2D.Double hourHand;
  private Line2D.Double minuteHand;
  private Line2D.Double secondHand;
  private int hour;
  private int minute;
  private int second;
  private long currentSecond;
  private int alarmHour;
  private int alarmMinute;
  private int alarmSecond;

  public ClockPanel()
  {
    // need inner class for listener, and attach listener
    // The following code is based on advice from the API under "Timer".
    int delay = 1000;
    ActionListener taskPerformer = new ActionListener()
    {
      public void actionPerformed(ActionEvent evt)
      {
         currentSecond = System.currentTimeMillis() / 1000;
         repaint();
      }
    };
    new Timer(delay, taskPerformer).start();

    // set attributes
    setPreferredSize(new Dimension(SIZE, SIZE));
    circle = new Ellipse2D.Double(BORDER, BORDER, 2*RADIUS, 2*RADIUS);

    hourMark = new Line2D.Double[12];
    for (int i = 0; i < 12; ++i)
    {
      // Each hour, the angle changes by 30 degrees, or PI/6.
      // Because pixel number increase downward, we need -sin.
      double x1 = CENTER + (CENTER-BORDER) * Math.cos(Math.PI/2 - Math.PI/6*i);
      double y1 = CENTER + (CENTER-BORDER) * -Math.sin(Math.PI/2 - Math.PI/6*i);
      double x2 = CENTER + (CENTER-2*BORDER) * Math.cos(Math.PI/2 - Math.PI/6*i);
      double y2 = CENTER + (CENTER-2*BORDER) * -Math.sin(Math.PI/2 - Math.PI/6*i);
      hourMark[i] = new Line2D.Double(x1, y1, x2, y2);
    }
  }

  // Draw the clock every second.
  public void paintComponent(Graphics g)
  {
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D) g;

    // now draw geometric shapes with g2.draw(---)
    g2.draw(circle);
    for (int i = 0; i < 12; ++i)
      g2.draw(hourMark[i]);

    // The code that updates the clock needs to be here because we want to
    // repaint every second.  The constructor only gets called once at the
    // beginning of the application.
    // Find out what time it really is to set hour, minute and second.
    // Note that the system time is always given in GMT.
    currentSecond = System.currentTimeMillis() / 1000;
    currentSecond -= 5 * 60 * 60;
    hour = (int) (currentSecond % (12 * 60 * 60) / (60 * 60));
    minute = (int) (currentSecond % (60 * 60) / 60);
    second = (int) (currentSecond % 60);

    // Each second, the angle changes by 6 degrees, or PI/30.
    double x1 = CENTER;
    double y1 = CENTER;
    double x2 = CENTER + (CENTER-3*BORDER) *  Math.cos(Math.PI/2 - Math.PI/30*second);
    double y2 = CENTER + (CENTER-3*BORDER) * -Math.sin(Math.PI/2 - Math.PI/30*second);
    secondHand = new Line2D.Double(x1, y1, x2, y2);

    // Now we need to continue with the minute hand and hour hand....
    double minuteAngle = Math.PI/2 - Math.PI/30*(minute + second/60.0);
    double hourAngle = Math.PI/2 - Math.PI/6*(hour + minute/60.0 + second/3600.0);

    x2 = CENTER + (CENTER - 6*BORDER) *  Math.cos(minuteAngle);
    y2 = CENTER + (CENTER - 6*BORDER) * -Math.sin(minuteAngle);
    minuteHand = new Line2D.Double(x1, y1, x2, y2);

    x2 = CENTER + (CENTER - 8*BORDER) *  Math.cos(hourAngle);
    y2 = CENTER + (CENTER - 8*BORDER) * -Math.sin(hourAngle);
    hourHand = new Line2D.Double(x1, y1, x2, y2);

    g2.draw(secondHand);
    g2.draw(minuteHand);
    g2.draw(hourHand);

    // Now, check to see if it's time to wake up!
    // Call the 'simple midi player' I found on the Web.
    if (hour == alarmHour && minute == alarmMinute && second == alarmSecond)
    {
      new VerySimpleMidiPlayer();
    }
  }

  // This function is called from the button listener in the InputPanel class.
  public void setAlarmTime(int h, int m, int s)
  {
    alarmHour = h;
    alarmMinute = m;
    alarmSecond = s;
  }
}