import java.applet.*;
import java.awt.event.*;
import java.awt.Graphics;
import java.awt.Color;
import java.awt.Image;
import java.awt.Font;
import java.util.ArrayList;
import java.util.Timer;
import java.util.TimerTask;
import java.awt.Rectangle;
import java.util.Random;

public class SpaceInvaders extends Applet implements KeyListener, MouseListener
{
  public static SpaceInvaders reference;
  public static Image playerShip,badShip,pow,shot,badshot,playerPOW;
  public static int score;
  public static int level;
  public static SpaceShip p;
  public static Image backbuffer;
  public static Graphics backg;
  public static Timer t;
  public static SpaceShip playerShot;
  public static boolean clearWait;
  public static boolean diedWait;
  public static int difficultyRC,difficultyT;
  public static SpaceShip alienShot;
  public static boolean started;
  public void init()
  {
    started = false;
    clearWait=false;
    diedWait = false;
    removeKeyListener(this);
    removeMouseListener(this);
    addKeyListener(this);
    addMouseListener(this);
    reference = this;
    backbuffer = createImage(getWidth(),getHeight());
    backg = backbuffer.getGraphics();
    backg.setColor(Color.white);
    playerPOW = getImage(getDocumentBase(),"playerPOW.GIF");
    playerShip = getImage(getDocumentBase(),"player.GIF");
    badShip = getImage(getDocumentBase(),"badship.GIF");
    pow = getImage(getDocumentBase(),"explosion.GIF");
    shot = getImage(getDocumentBase(),"shot.GIF");
    badshot = getImage(getDocumentBase(),"badshot.GIF");
    difficultyRC = 3;
    difficultyT = 100;
    score = 0;
    level = 1;
    p = new SpaceShip(250,350,playerShip,29,29);
    playerShot = new SpaceShip();
    playerShot.shooting = false;
    playerShot.width=7;
    playerShot.height=8;
    alienShot=new SpaceShip();
    alienShot.shooting=false;
    alienShot.width=4;
    alienShot.height=7;
    AlienGroup.newGroup(difficultyRC,difficultyRC);
    t= new Timer();
  }

  public void refresh()
  {

    backg.setColor(Color.black);
    backg.fillRect(0,0,501,501);
    backg.setColor(Color.white);
    backg.drawRect(0,0,500,500);
    backg.drawLine(0,400,500,400);
    backg.setFont(new Font("courier",Font.ITALIC,20));
    backg.drawString(("Score: " + score),10,430);
    backg.drawString(("Level: " + level),10,460);
    backg.setColor(new Color(200,0,0));
    backg.drawLine(1,300,499,300);
    backg.setColor(Color.green);
    backg.setFont(new Font("courier",Font.ITALIC,40));
    backg.drawString("SPACE INVADERS",150,450);
    backg.setFont(new Font("courier",Font.ITALIC,12));
    backg.drawString("By Billy Harmon",250,470);
    backg.drawImage(playerShip,p.x,p.y,null);

    ArrayList temp;
    for(int i = 0; i < AlienGroup.theGroup.size(); i++)
    {
      temp = (ArrayList)AlienGroup.theGroup.get(i);
      for(int j = 0; j < temp.size(); j++)
      {
        if(((SpaceShip)temp.get(j)).alive)
          backg.drawImage(((SpaceShip)temp.get(j)).img,((SpaceShip)temp.get(j)).x,((SpaceShip)temp.get(j)).y,null);
      }
    }
    if(playerShot.shooting)
    {
      backg.drawImage(shot,playerShot.x,playerShot.y,null);
    }
    if(AlienGroup.allDead)
    {
      t.cancel();
      backg.setColor(Color.green);
      backg.setFont(new Font("courier",Font.ITALIC,40));
      backg.drawString("Zone Cleared!",100,210);
      backg.setFont(new Font("courier",Font.ITALIC,20));
      backg.drawString("click to continue",150,250);
      clearWait = true;
    }
    if(!p.alive)
    {
      t.cancel();
      backg.drawImage(playerPOW,p.x,p.y,null);
      backg.setColor(Color.red);
      backg.setFont(new Font("courier",Font.ITALIC,40));
      backg.drawString("GAME OVER",100,210);
      backg.setFont(new Font("courier",Font.ITALIC,20));
      backg.drawString("click to continue",150,250);
      diedWait = true;
    }
    if(alienShot.shooting)
    {
      backg.drawImage(badshot,alienShot.x+8,alienShot.y,null);
    }
    if(!started)
    {
      backg.setColor(Color.white);
      backg.drawString("CLICK TO START",200,200);
    }

  }

  public void update( Graphics g )
  {
    refresh();
    g.drawImage( backbuffer, 0, 0, this );
  }


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

  public void keyTyped(KeyEvent e)
  {
    switch(e.getKeyChar())
    {
      case 'w':
      {
        if(!playerShot.shooting)
        {
          playerShot.shooting = true;
          playerShot.x = p.x+14;
          playerShot.y = p.y+10;
          SpaceInvaders.reference.t.scheduleAtFixedRate(new MovePlayerShots(),30, 30);
        }
        break;
      }
      case 'a':
      {
        if(SpaceInvaders.reference.p.x>=20)
          SpaceInvaders.reference.p.x-=20;
        repaint();
        break;
      }
      case 'd':
      {
        if(SpaceInvaders.reference.p.x<=450)
          SpaceInvaders.reference.p.x+=20;
        repaint();
        break;
      }
    }
  }
  public void keyPressed(KeyEvent e){}
  public void keyReleased(KeyEvent e){}
  public void mouseClicked(MouseEvent e)
  {
    if(clearWait)
    {
      t = new Timer();
      difficultyRC++;
      difficultyT-=10;
      level++;
      alienShot.shooting=false;
      AlienGroup.newGroup(difficultyRC,difficultyRC);
      t.scheduleAtFixedRate(new MoveAliens(),difficultyT,difficultyT);
      clearWait=false;
    }
    if(diedWait)
    {
      init();
    }
    if(!started)
    {
      started=true;
      t.scheduleAtFixedRate(new MoveAliens(),difficultyT,difficultyT);
    }
  }
  public void mouseEntered(MouseEvent e){}
  public void mouseExited(MouseEvent e){}
  public void mousePressed(MouseEvent e){}
  public void mouseReleased(MouseEvent e){}

}

class SpaceShip extends Rectangle
{
  public SpaceShip(){}
  public boolean shooting;
  public boolean alive;
  public Image img;
  public SpaceShip(int cx, int cy, Image i,int h, int w)
  {
    super(cx,cy,w,h);
    img = i;
    alive = true;
  }
}

final class AlienGroup
{
  public static ArrayList theGroup;
  private static ArrayList rows;
  public static int row,col;
  public static boolean forward = true;
  public static boolean allDead=false;
  public static int deathCount=0;

  public static SpaceShip randomShip()
  {
    Random r = new Random();
    SpaceShip returnShip;
    do
    {
      returnShip = (SpaceShip) ( (ArrayList) theGroup.get(adjustRows() - 1)).get(r.nextInt(col));
    }while (!returnShip.alive);
    return returnShip;
  }

  public static void newGroup(int r,int c)
  {
    row = r; col = c;
    int drawX=20;
    int drawY=0;
    deathCount=0;
    allDead = false;
    forward = true;
    theGroup = new ArrayList();
    rows = new ArrayList();
    for(int i = 0; i < r; i++)
    {
      for(int j = 0; j < c; j++)
      {
        rows.add(new SpaceShip(drawX,drawY+30,SpaceInvaders.reference.badShip,15,21));
        drawX+=20;
      }
      theGroup.add(rows);
      rows = new ArrayList();
      drawX=20;
      drawY+=30;
    }
  }

  public static int adjustRows()
  {
    boolean all = true;
    int returnRow = 0;
    for(int i = 0; i < theGroup.size(); i++)
    {
      for(int j = 0; j < ((ArrayList)theGroup.get(i)).size(); j++)
      {
        if(((SpaceShip)((ArrayList)theGroup.get(i)).get(j)).alive)
        {
          all = false;
        }
      }
      if(all)
        returnRow++;
      all = true;
    }
    return row-returnRow;
  }

  public static void down()
  {
    for(int i = 0; i < theGroup.size(); i++)
    {
      for(int j = 0; j < ((ArrayList)theGroup.get(i)).size(); j++)
      {
        ((SpaceShip)((ArrayList)theGroup.get(i)).get(j)).y+=20;
      }
    }

  }
  public static void left()
  {
    for(int i = 0; i < theGroup.size(); i++)
    {
      for(int j = 0; j < ((ArrayList)theGroup.get(i)).size(); j++)
      {
        ((SpaceShip)((ArrayList)theGroup.get(i)).get(j)).x-=5;
      }
    }

  }

  public static void right()
  {
    for(int i = 0; i < theGroup.size(); i++)
    {
      for(int j = 0; j < ((ArrayList)theGroup.get(i)).size(); j++)
      {
        ((SpaceShip)((ArrayList)theGroup.get(i)).get(j)).x+=5;
      }
    }
  }

  public static int[] hit()
  {
    for(int i = 0; i < theGroup.size(); i++)
    {
      for(int j = 0; j < ((ArrayList)theGroup.get(i)).size(); j++)
      {

        if(((SpaceShip)((ArrayList)theGroup.get(i)).get(j)).intersects(SpaceInvaders.reference.playerShot)&&
           ((SpaceShip)((ArrayList)theGroup.get(i)).get(j)).alive)
        {
          deathCount++;
          SpaceInvaders.reference.score+=10;
          if(deathCount>=row*col)
          {
            allDead=true;
          }
          return new int[] {j,i};
        }
      }
    }
    return new int[] {-1,-1};
  }
}

class MoveAliens extends TimerTask
{
  public void run()
  {
    if(AlienGroup.forward)
    {
      if(((SpaceShip)((ArrayList)AlienGroup.theGroup.get(0)).get(AlienGroup.col-1)).x <= 470)
      {
        AlienGroup.right();
      }
      else
      {
          AlienGroup.down();
          AlienGroup.forward = false;
      }
    }
    else
    {
        if(((SpaceShip)((ArrayList)AlienGroup.theGroup.get(0)).get(0)).x >= 20)
        {
          AlienGroup.left();
        }
        else
        {
            AlienGroup.down();
            AlienGroup.forward = true;
        }
    }
    if(((SpaceShip)((ArrayList)AlienGroup.theGroup.get(AlienGroup.adjustRows()-1)).get(0)).y>=278)
    {
      SpaceInvaders.reference.p.alive=false;
    }
    if(SpaceInvaders.reference.clearWait)
      cancel();
    if(!SpaceInvaders.reference.alienShot.shooting)
    {
      SpaceInvaders.reference.alienShot.shooting=true;
      SpaceShip temp = AlienGroup.randomShip();
      SpaceInvaders.reference.alienShot.x=temp.x;
      SpaceInvaders.reference.alienShot.y=temp.y;
      SpaceInvaders.reference.t.scheduleAtFixedRate(new MoveAlienShots(),30,30);
    }
    SpaceInvaders.reference.repaint();
  }
}

class MovePlayerShots extends TimerTask
{
  public void run()
  {
    int[] checkHit = AlienGroup.hit();
    if(checkHit[0] == -1)
    {
      SpaceInvaders.reference.playerShot.y-=10;
    }
    else if(checkHit[0] != -1)
    {
        ((SpaceShip)((ArrayList)AlienGroup.theGroup.get(checkHit[1])).get(checkHit[0])).img =
                                                           SpaceInvaders.reference.pow;
        SpaceInvaders.reference.t.schedule(new PowDelay(
        ((SpaceShip)((ArrayList)AlienGroup.theGroup.get(checkHit[1])).get(checkHit[0])))
                                           ,400);
        SpaceInvaders.reference.playerShot.shooting=false;
        cancel();
    }

    if(SpaceInvaders.reference.playerShot.y<=0)
    {
      SpaceInvaders.reference.playerShot.shooting=false;
      cancel();
    }

    SpaceInvaders.reference.repaint();
  }
}

class PowDelay extends TimerTask
{
  public SpaceShip dead;
  public PowDelay(SpaceShip d)
  {
    dead = d;
  }
  public void run()
  {
    dead.alive = false;
    cancel();
  }
}

class MoveAlienShots extends TimerTask
{
  public void run()
  {
    if(SpaceInvaders.reference.p.intersects(SpaceInvaders.alienShot))
    {
      SpaceInvaders.reference.p.alive=false;
    }
    else
      SpaceInvaders.reference.alienShot.y+=10;
    if(SpaceInvaders.reference.alienShot.y>=400)
    {
      SpaceInvaders.reference.alienShot.shooting=false;
      cancel();
    }
    SpaceInvaders.reference.repaint();
  }
}