import java.awt.*;
import java.awt.Graphics;
import java.awt.Image;
import java.util.Vector;
import java.util.*;
import java.applet.*;

public class AlgebraTiles extends Applet {
    AlgebraTilesCanvas canvas;
    Button NewQuadraticButton, StraightenButton;
    int DifficultyLevel;
    boolean Practice;
    MessageCanvas message;
    public void init() {
	System.out.println("Begin of init");
	setLayout( new BorderLayout() );

	String param = getParameter("practice");
	if ( param==null || ! param.equalsIgnoreCase("no") ) 
	    Practice = true;
	else
	    Practice = false;
	param = getParameter("difficulty");
	if ( param==null || param.equals("1") )
	    DifficultyLevel=1;
	else if ( param.equals("2") )
	    DifficultyLevel=2;
//	else if ( param.equals("3") )
//	    DifficultyLevel=3;
	else
	    DifficultyLevel=1;

	canvas = new AlgebraTilesCanvas( size().width, size().height - 100 
);
	canvas.resize( size().width, size().height - 100 );
	System.out.println("NewEquation");
	newEquation();
	add( "North", canvas );

	System.out.println("new q panel");
	Panel q = new Panel();
	q.setLayout( new BorderLayout() );
//	q.add("Center", new Label("test") );

	Panel p = new Panel();
	p.setLayout( new BorderLayout() );
	p.setBackground( Color.white );
	p.add("Center", new Label("Click on 'New Quadratic' for a new problem", Label.CENTER));
	System.out.println("Before new buttons");

	if ( Practice )
	    NewQuadraticButton = new Button("New Tiles");
	else
	    NewQuadraticButton = new Button("New Quadratic");

	p.add("East", NewQuadraticButton );

	StraightenButton = new Button("Straighten");
	p.add("West", StraightenButton );
	q.add("North", p );

	message = new MessageCanvas(size().width, 75);
	q.add("South", message );

	add("South", q);
	System.out.println("End of init");
    }

    public boolean action(Event evt, Object what) {
	if ( evt.target == NewQuadraticButton ) {
	    newEquation();
	    message.setMessage("New Equation");
	} else if ( evt.target == StraightenButton ) {
	    canvas.StraightenTiles();
	    message.setMessage("Straighten Tiles");
	} else
	    return super.action(evt,what);
	return true;
    }

    void newEquation() {
        int n1=0,n2=0,n3=0,n4=0;
        n1 = getRandom(2,-1);
	n3 = getRandom(3,-1);
	n2 = getRandom(5,2);
	n4 = getRandom(7,3);
	if ( DifficultyLevel==1 || Practice ) {
	    n2 = Math.abs( n2 );
	    n4 = Math.abs( n2 );
	}
	canvas.newEquation(n1*n3,n2*n3,n1*n4,n2*n4, Practice);
        System.out.println("End of newEquations");
    }

    int getRandom(int n, int m) {
	return (int)( Math.floor( Math.random() * n ) - m );
    }
}

class AlgebraTilesCanvas extends Canvas {
    int Width, Height;
    Font font, smfont;
    FontMetrics fm, smfm;
    Image osI;
    Graphics osG;
    Color bgColor = new Color( 46, 130, 46);
    int Acoef=0, B1coef=0, B2coef, Bcoef, Ccoef=0;
    String Quadratic = "";
    int strWidth=0, strHeight;
    Vector Tiles;
    int currTile = -1, xoff, yoff;
    boolean Practice;

    public AlgebraTilesCanvas(int w, int h) {
	Width = w;
	Height = h;
	osI = null;
	font = new Font( "TimesRoman", Font.BOLD, 14 );
	fm = getFontMetrics( font );
	smfont = new Font( "TimesRoman", Font.BOLD, 12 );
	smfm = getFontMetrics( smfont );
	setFont( font );
	strHeight = 3*fm.getAscent()/2;
	Tiles = new Vector(0);
    }

    public void newEquation(int a, int b1, int b2, int c, boolean practice) {
	Practice = practice;
	Acoef = a;
	B1coef = b1;
	B2coef = b2;
	Bcoef = B1coef + B2coef;
	Ccoef = c;
	boolean Reduced = true;
	while ( Reduced ) {
	    Reduced = false;
	    if ( (Acoef%2==0) && (Bcoef%2==0) && (Ccoef%2==0) ) {
	        Acoef /= 2;
	        B1coef /= 2;
	        B2coef /= 2;
	        Ccoef /= 2;
		Reduced = true;
	    } else if ( (Acoef%3==0) && (Bcoef%3==0) && (Ccoef%3==0) ) {
		Acoef /= 3;
		B1coef /= 3;
		B2coef /= 3;
		Ccoef /= 3;
		Reduced = true;
	    }
	    Bcoef = B1coef + B2coef;
	}

	Tiles = createTiles();
//	if ( Acoef>1 )
//	    Quad1= Acoef + "x^2";
//	Quadratic = Acoef + "x^2 + " + (B1coef+B2coef) + "x + "+ Ccoef;
//	strWidth = fm.stringWidth( Quadratic );
	repaint();
    }

    /*  StraightenTiles
	Find tiles which are close to being lined up either 
	horizontally or vertically.

	Algorithm depends on the fact that tiles are ordered according to 
	size.
    */

    public void StraightenTiles() {
       int tol = 8;
       for (int i=0;i<Tiles.size();i++) {
	  Tile tile1 = (Tile)Tiles.elementAt(i);
	  for (int j=i+1; j<Tiles.size(); j++) {
	     Tile tile2 = (Tile)Tiles.elementAt(j);
	     if ( Math.abs( tile1.ypos - tile2.ypos ) < tol )
	        tile2.ypos = tile1.ypos;
	     if ( Math.abs(tile1.ypos + tile1.height - tile2.ypos) < tol )
	        tile2.ypos = tile1.ypos + tile1.height;
	     if ( Math.abs( tile1.xpos - tile2.xpos ) < tol )
		tile2.xpos = tile1.xpos;
	     if ( Math.abs(tile1.xpos + tile1.width - tile2.xpos) < tol )
	        tile2.xpos = tile1.xpos + tile1.width;
	  }
       }
       for (int i=Tiles.size()-1;i>=0;i--) {
	  Tile tile1 = (Tile)Tiles.elementAt(i);
	  for (int j=i-1; j>=0; j--) {
	     Tile tile2 = (Tile)Tiles.elementAt(j);
	     if ( Math.abs( tile1.ypos - tile2.ypos ) < tol )
	        tile2.ypos = tile1.ypos;
	     if ( Math.abs(tile1.ypos + tile1.height - tile2.ypos) < tol )
	        tile2.ypos = tile1.ypos + tile1.height;
	     if ( Math.abs( tile1.xpos - tile2.xpos ) < tol )
		tile2.xpos = tile1.xpos;
	     if ( Math.abs(tile1.xpos + tile1.width - tile2.xpos) < tol )
	        tile2.xpos = tile1.xpos + tile1.width;
	  }
       }
       repaint();
    }

    public boolean isCorrect() {
	return true;
    }

    private Vector createTiles() {
	currTile = -1;
        Vector tiles;
	tiles = new Vector();
	int i, sgn;
	if ( Acoef<0 )  sgn = -1;
	else		sgn = 1;
	Tile tmptile = new Tile(2,2,1);
	for (i=0;i<Math.abs(Acoef);i++) {
	    tmptile = new Tile( 2, 2, 2*i, 2*i, sgn );
	    tiles.addElement( tmptile );
	}
	int xp = tmptile.width;
	if ( B1coef<0 )  sgn = -1;
	else		sgn = 1;
	for (i=0;i<Math.abs(B1coef);i++) {
	    tmptile = new Tile( 2, 1, xp + 2*i, 2*i, sgn );
	    tiles.addElement( tmptile );
	}
	if ( B2coef<0 )  sgn = -1;
	else	 	 sgn = 1;
	for (i=0;i<Math.abs(B2coef);i++) 
	    tiles.addElement( new Tile(2, 1,
					xp + 2*(i+Math.abs(B1coef)),
					2*(i+Math.abs(B1coef)),
					sgn) );
	xp += tmptile.width;
	if ( Ccoef<0 )  sgn = -1;
	else		sgn = 1;
	for (i=0;i<Math.abs(Ccoef);i++)
	    tiles.addElement( new Tile(1, 1, xp + 2*i, 2*i, sgn) );
	return tiles;
    }

    public boolean mouseDown(Event evt, int x, int y) {
	for (int i=Tiles.size()-1;i>=0;i--) {
	    Tile tile = (Tile)Tiles.elementAt(i);
	    if ( tile.inside(x,y) ) {
		currTile = i;
		xoff = x - tile.xpos;
		yoff = y - tile.ypos;
		repaint();
		return true;
	    }
	}
	currTile = -1;
	return super.mouseDown(evt,x,y);
    } 

    public boolean mouseDrag(Event evt, int x, int y) {
	if ( currTile>=0 ) {
	    Tile tile = (Tile)Tiles.elementAt( currTile );
	    tile.move(x-xoff,y-yoff);
	    repaint();
	    return true;
	}
	return super.mouseDrag(evt,x,y);
    }

    public boolean keyDown(Event evt, int key) {
	if ( (currTile>=0) && (key==32) ) {
	    Tile tile = (Tile)Tiles.elementAt(currTile);
	    tile.flip();
	    repaint();
	    return true;
	}
	return super.keyDown( evt, key );
    }

    public void paint(Graphics g) {
        if ( osI==null ) {
	    osI = createImage( Width, Height);
	    if ( osI==null ) {
	        System.out.println("osI is null. bailing . . .");
	        System.exit(1);
	    }
            osG = osI.getGraphics();
	}
	osG.setColor( bgColor );
        osG.fillRect( 0, 0, Width, Height );
	osG.setColor( new Color( 215, 255, 215) );
	osG.drawRect( 0, 0, Width-1, Height-1 );
	if ( ! Practice )
	    drawEquation(osG);
/*
	osG.setColor( Color.black );
	osG.fillRect( 0, 95, 205, 3 );
	osG.fillRect( 205, 0, 3, 95 );
	osG.setColor( new Color(215, 255, 215) );
	osG.drawLine( 0, 97, 97, 97 );
	osG.drawLine( 97, 0, 97, 97 );
*/
	for (int i=0; i<Tiles.size(); i++) {
	    Tile tile = (Tile)Tiles.elementAt(i);
	    tile.paint(osG, false, Practice);
	}
	if ( currTile>= 0 ) {
	    Tile tile = (Tile)Tiles.elementAt(currTile);
	    tile.paint(osG, true, Practice);
	}
	g.drawImage(osI,0,0,this);
    }

    private void drawEquation(Graphics g) {
	int xp = Width - 3;
	String tmp;
	g.setFont( font );
	if ( Ccoef != 0 ) {
	    if ( Ccoef > 0 )
	        tmp = " + " + Ccoef;
	    else
		tmp = " - " + Math.abs(Ccoef);
	    xp -= fm.stringWidth(tmp);
	    g.drawString( tmp, xp, strHeight );
	}
	if ( Bcoef != 0 ) {
	    if ( Bcoef > 1 )
	        tmp = " + " + Bcoef +"x";
	    else if ( Bcoef == 1 )
		tmp = " + x";
	    else if ( Bcoef < -1 )
		tmp = " - " + Math.abs(Bcoef) + "x";
	    else // Bcoef==-1
		tmp = " - x";
	    xp -= fm.stringWidth(tmp);
	    g.drawString( tmp, xp, strHeight );
	}
	g.setFont( smfont );
	xp -= smfm.stringWidth("2");
	g.drawString("2", xp, strHeight / 2+2 );
	g.setFont( font );
	if ( Acoef > 1 )
	   tmp = "" + Acoef + "x";
	else if ( Acoef==1 )
	   tmp = "x";
	else if ( Acoef==-1 )
	   tmp = "-x";
	else
	   tmp = "-" + Math.abs(Acoef) +"x";
	xp -= fm.stringWidth(tmp);
	g.drawString( tmp, xp, strHeight );

	g.drawRect( xp - 5, 0, Width-xp+5, strHeight+5 );
    }

    public void update(Graphics g) {
	paint(g);
    }
}

/*
   type		Value
    1		  1
    2		  X
*/
class Tile extends Object {
    int Base = 21;
    int WidthType, HeightType;
    public int xpos, ypos, width, height;
    Color color;
    String WidthString, HeightString;

    public Tile(int wtype, int htype, int x, int y, int sign) {
	initialize( wtype, htype, sign );
	xpos = x;
	ypos = y;
    }

    public Tile(int wtype, int htype, int sign) {
	initialize( wtype, htype, sign );
	xpos = 0;
	ypos = 0;
    }

    private void initialize(int wtype, int htype, int sign) {
        WidthType = wtype;
	HeightType = htype;
	if ( WidthType==1)
	    width = Base;
	else if ( WidthType==2 )
	    width = 13*Base/3;
	else
	    width = 0;
	if ( HeightType==1 )
	    height = Base;
	else if ( HeightType==2 )
	    height = 13*Base/3;
	else
	    height = 0;
	if ( sign < 0 )
	    color = new Color( 100, 75, 75 );
	else
	    color = new Color( 235, 190, 190 );

	if ( (sign<0) && ( WidthType==1 ) )
	    WidthString = "-1";
	else if ( (sign>0) && ( WidthType==1 ) )
	    WidthString = "1";
	else if ( (sign<0) && ( WidthType==2 ) )
	    WidthString = "-X";
	else if ( (sign>0) && ( WidthType==2 ) )
	    WidthString = "X";
	else
	    WidthString = "";

	if ( (sign<0) && ( HeightType==1 ) )
	    HeightString = "-1";
	else if ( (sign>0) && ( HeightType==1 ) )
	    HeightString = "1";
	else if ( (sign<0) && ( HeightType==2 ) )
	    HeightString = "-X";
	else if ( (sign>0) && ( HeightType==2 ) )
	    HeightString = "X";
	else
	    HeightString = "";
    }

    public void move(int x, int y) {
	xpos = x;
	ypos = y;
    }

    public void flip() {
	int tmp = width;
	width = height;
	height = tmp;
	tmp = WidthType;
	WidthType = HeightType;
	HeightType = WidthType;
	String tstr = WidthString;
	WidthString = HeightString;
	HeightString = tstr;
    }

    public boolean inside(int x, int y) {
	if ( ( x >= xpos) && (x <= xpos + width) &&
	     ( y >= ypos) && (y <= ypos + height) )
	    return true;
	return false;
    }

    public void paint(Graphics g, boolean active, boolean practice) {
	g.setColor( color );
	g.fillRect( xpos, ypos, width, height );
	g.setColor( Color.black );
	g.drawRect( xpos, ypos, width-1, height-1 );
	g.drawRect( xpos+1, ypos+1, width-3, height-3 );
	if ( ! practice ) {
	    g.drawString( HeightString, xpos+3, ypos+height/2+5 );
	    g.drawString( WidthString, xpos+width/2-5, ypos-1 );
	}
	if (active) {
	    g.setColor( Color.red );
	    g.drawRect( xpos, ypos, width-1, height-1 );
	}
    }
}