import java.awt.*;
public class interactingletters extends fallingletterrefreshes	//has all the methods inherited from fallingletterrefreshes
{
	public static final Font FONT= new Font("Serif", Font.BOLD, 20);
	protected int xmax, ymax, x2ago, y2ago;	protected float vx;	//vx is the velocity left or right	
	public final int UP=1, DOWN=2, LEFT=4, RIGHT=8;		//I chose the values as I did for bitmasking, just constants for direction
	protected static Color background;			//now I can set the background staticly for all the letters
	//This time I let the applet pass in the right boundry of the animation (where it should bounce off the walls, since it will move left and right now) and the 'ground' (maximum y coordinate)	
	public interactingletters(char newletter, int newx, int newy, int rightbound, int ground)	
	{
		super(newletter, newx, newy);
		xmax=rightbound;
		ymax=ground;
		background = Color.black;
	}
	//method that returns the centerpoint, called by the interact() method so it can know the location of the other letter
	public Point getPoint()
	{
		return (new Point(x, y));
	}
	//Set the background the letters refresh to something other than black
	public void setBackground(Color color)
	{
		background = color;
	}
	//overrides update- now if the letter is at one of the sides, it will bounce it in the other direction
	public void update()
	{
		x+=(int)vx;		//now I have to track the x position, too
		y+=v;
		v+=1;
		if (vx<=-1)
			vx+=.1;
		else if (vx>=1)
			vx-=.1;		//vx goes toward 0 by .1 each frame
		if (y>ymax)
		{
			y=ymax;		//this helps make sure the letters don't get grounded
			bounce(UP);
		}
		else if (y<0)
			bounce(DOWN);
		if (x>xmax-10)
			bounce(LEFT);
		else if (x<0)
			bounce(RIGHT);
	}
	//I've always wanted to make a method do this, it might be nicer if it took in a strength, too, though.
	//Basically it sets the direction in the direction of the bounce and if it's bouncing up, it reduces it slightly to simulate imperfect elasticity (so it settles a little at a time)
	public void bounce(int direction)
	{
		if ((direction&UP)>0)
			v=-9*Math.abs(v)/10;
		else if ((direction&DOWN)>0)
			v=Math.abs(v);
		if ((direction&LEFT)>0)
			vx=-Math.abs(vx);
		else if ((direction&RIGHT)>0)
			vx=Math.abs(vx);
	}
	//checks if two letters are close enough to bounce off each other and calls bounce in the appropriate direction
	public void interact(interactingletters letter2)
	{
		int x2 = letter2.getPoint().x;
		int y2 = letter2.getPoint().y;
		int bounce1=0, bounce2=0;
		if (Math.abs(x-x2)<=10 && Math.abs(y-y2)<=20 &! Character.isWhitespace(letter) &! Character.isWhitespace(letter2.getLetter()))	//if the letters are 'touching' each other and neither is whitespace (no one wants spaces bouncing off other letters)
		{
			if (x<x2)		//if the current letter is to the left of letter2
			{
				vx=x-x2;
				letter2.setVX(x2-x);	//power of the bounce set relative to the distance of the letters, more bounce further out
				bounce1 |=LEFT;
				bounce2 |=RIGHT;
			}
			else if (x2<x)		//if the currentletter is to the right of letter2
			{
				vx=x2-x;
				letter2.setVX(x-x2);
				bounce1 |=RIGHT;
				bounce2 |=LEFT;
			}
			if (y>y2)		//if the current letter is under letter2
			{
				bounce1 |=DOWN;
				bounce2 |=UP;
			}
			else if (y2>y)		//if the current letter is above letter2
			{
				bounce1 |=UP;
				bounce2 |=DOWN;
			}
			bounce(bounce1);
			letter2.bounce(bounce2);
		}
	}
	//overridden to set vx to 0 while dragging so it doesn't remember the old velocity
	public void update(int x, int y)
	{
		this.x=x+xoffset;
		this.y=y+yoffset;
		v=0;
		vx=0;
	}
	//decides on a direction for v and vx based on where the mouse was two animation frames ago
	public void release(int x, int y)
	{
		vx = (x-x2ago)/2;
		v = (y-y2ago)/2;
	}
	//sets the power of vx in the object, used to set the 'power' of the bounce in interact()
	public void setVX(int newvx)
	{
		vx=newvx;
	}
	//overriden to keep track of the x,y coordinates 2 frames ago for use in release()
	public void draw(Graphics g)
	{
		g.setColor(background);
		g.drawString(new String("") + letter, lastx, lasty);
		g.setColor(color);
		g.drawString(new String("") + letter, x, y);
		x2ago=lastx;					//stores the location 2 frames ago for release()
		y2ago=lasty;
		lastx=x;
		lasty=y;
	}
	//returns the value of the letter, used by interact() to see if it's whitespace
	public char getLetter()
	{
		return letter;
	}
}