import java.awt.*;
import java.applet.*;
//This applet displays letters randomly around the screen that fade in and then gravitate to appropriate 
//positions to spell out a Happy Birthday message.  Parameters are taken from the HTML file.
public class HappyBirthday extends Applet implements Runnable
{
	public final int WIDTH=500, HEIGHT=300;
	public String name, message, birthdaymessage;
	centerletter[] nameletters, birthdayletters, messageletters;	//three arrays of letter objects for the three messages
	Thread anim;
	public int framecount;
	
	public void init()
	{
		setSize(WIDTH, HEIGHT);
		setBackground(Color.black);
		framecount=0;
		name=getParameter("bname");		//name of person taken from the webpage
		message=getParameter("message");	//message to the person taken from webpage
		birthdaymessage="Happy Birthday,";	//birthday message is hard coded
		birthdayletters= new centerletter[birthdaymessage.length()];	//three letters made into arrays of letter objects
		nameletters = new centerletter[name.length()];
		messageletters = new centerletter[message.length()];
		int Xstart = 250 - (birthdaymessage.length()*15);
		for (int i=0; i<birthdaymessage.length(); i++)
		{
			birthdayletters[i]=new centerletter(birthdaymessage.charAt(i), Xstart+25*i, 80, (int)(Math.random()*500), (int)(Math.random()*300));
		}
		Xstart = 250-(name.length()*15);
		for (int i=0; i<name.length(); i++)
		{
			nameletters[i] = new centerletter(name.charAt(i), Xstart+25*i, 160, (int)(Math.random()*500), (int)(Math.random()*300));
		}
		Xstart = 250-(message.length()*15);
		for (int i=0; i<message.length(); i++)
		{
			messageletters[i] = new centerletter(message.charAt(i), Xstart+25*i, 260, (int)(Math.random()*500), (int)(Math.random()*300));
		}
	}
	//This method draws the letters in their spots, starting them in sequence, one at a time, starting one every 10 animation frames
	public void paint(Graphics g)
	{
		int i = framecount/10;		//i is the number of letters to animate in the happy birthday message
		int j=0, k=0, l=0;
		if (i>birthdaymessage.length())
			i=birthdaymessage.length();
		for (j=0; j<i; j++)
			if (!birthdayletters[j].isStopped())
				birthdayletters[j].animate();		//at this point, j is the number of letters animated in the birthday message
		if (i==birthdaymessage.length())
		{
			i=framecount/10-3-birthdaymessage.length();	//i becomes the number of letters to animate in the name if all the letters
			if (i>name.length())				//in the birthday message are being animated
				i=name.length();
			if (i>=0)
			{
				for (k=0; k<i; k++)
					if (!nameletters[k].isStopped())
						nameletters[k].animate();
			}						//at this point, k is the number of letters animated in the name
			if (i==name.length())
			{
				i=framecount/10-6-birthdaymessage.length()-name.length();	//now i becomes the number of letters to animate in the
				if (i>message.length())						//extra birthday message.
					i=message.length();
				if (i>=0)
				{
					for (l=0; l<i; l++)
						if (!messageletters[l].isStopped())
							messageletters[l].animate();
				}					//at this point, l is the number of letters animated in the message
			}
		}
		if (j>0)
			for (int temp=0; temp<j; temp++)
				birthdayletters[temp].paint(g);
		if (k>0)
			for (int temp=0; temp<k; temp++)
				nameletters[temp].paint(g);
		if (l>0)
			for (int temp=0; temp<l; temp++)		//now I draw all the letters involved- it would probably be better to make this the 
				messageletters[temp].paint(g);		//first part of paint and then make the animation changes, it might provide a little less flicker.
		boolean running=false;
		for (int a=0; a<birthdaymessage.length(); a++)		//checks if all the letters in all the messages are stopped yet
			if (!birthdayletters[a].isStopped())
				running=true;
		for (int a=0; a<name.length(); a++)
			if (!nameletters[a].isStopped())
				running = true;
		for (int a=0; a<message.length(); a++)
			if (!messageletters[a].isStopped())
				running = true;
		if (!running)
			stop();						//stops the thread if all the letters are stopped, no reason to keep it going.
	}
	public void start()
	{
		anim = new Thread(this);
		anim.start();
	}
	public synchronized void stop()
	{
		anim=null;
		notify();
	}
	public synchronized void run()
	{
		while (Thread.currentThread()==anim)
		{
			framecount++;					//all the animation pretty much is happening in the paint method, the animate methods could just as well be called here,
			repaint();					//but as it is, this just adds to the frame count and repaints.
			try
			{
				wait(100);
			}
			catch (InterruptedException e)
			{
				return;
			}
		}
	}
}