<iframe width='500px' height='400px' src='https://nest.ktbyte.com/nest#402' allowfullscreen></iframe>

PImage spaceship;
PImage bullets;
PImage alien1, alien2, alien3;
ArrayList <Bullet> arrayBullets= new ArrayList<Bullet>();
ArrayList <Aliena> arrayAliensa = new ArrayList<Aliena>();
ArrayList <Alienb> arrayAliensb = new ArrayList<Alienb>();
ArrayList <Alienc> arrayAliensc = new ArrayList<Alienc>();
int bulletTime = 5;
int score = 0;
int lives = 5;
int stage = 2;
String state = "game";
boolean shotA = false;
boolean shotB = false;
boolean shotC = false;

class Bullet {
  int x, y;
  Bullet() {
  }

  void displayBullets() {
    image(bullets, x, y);
  }
}

class Aliena {
  float a, b;
  Aliena() {
  }
  void displayA() {
    image(alien1, a, b, 50, 50);
  }
}
class Alienb {
  float a, b;
  Alienb() {
  }
  void displayB() {
    image(alien2, a, b, 50, 50);
  }
}
class Alienc {
  float a, b;
  Alienc() {
  }
  void displayC() {
    image(alien3, a, b, 50, 50);
  }
}
void setup() {
  if (state == "game") {
    noCursor();
    size(500, 700);
    spaceship = loadImage("http://www.clipartlord.com/wp-content/uploads/2014/04/spaceship4.png");
    bullets = loadImage("http://icons.iconarchive.com/icons/calle/smith-and-wesson/32/Single-Bullet-icon.png");
    alien1 = loadImage("http://png-1.findicons.com/files/icons/476/space/256/alien.png");
    alien2 = loadImage("http://mascot.crystalxp.net/png/nelson-alien-2-2774.png");
    alien3 = loadImage("http://dc604.4shared.com/img/1jHYYWI3/s3/13738cea1d8/Alien_Logo.png");
  }
}

void draw() {
  background(0, 0, 0);
  if (state == "stagescreen") {
//    textSize(36);
    text("Level :" + stage, width/2-50, height/2-15);
    text("Click for Next Level", width/2-160, height/2+15);
    if (mousePressed == true) {
      state = "game"; 
      stage++;
      frameCount = 0;
      arrayAliensa.clear();
      arrayAliensb.clear();
      arrayAliensc.clear();
    }
  }
  if (state=="game over") {
    text("GAME OVER", width/2, height/2-10);
    text("CLICK TO TRY AGAIN", width/2, height/2+10);
    if (mousePressed == true) {
      state="game";
      lives = 5;
      frameCount = 0; 
      stage = 2;
    }
  }
  if (state=="game") {
    int alienTimea = 4+stage, alienTimeb = 6+stage, alienTimec = 8+stage;
    float timeFrame = 20-(frameCount/60);
    image(spaceship, mouseX-25, mouseY-25, 50, 50);
    // create bullet every 2 seconds
    text("Score: " + score, 10, 20);
    text("Lives: " + lives, 10, 30);
    text("Time: " + int(timeFrame), 10, 40);
    if (frameCount % 15 == 0) {
      Bullet b = new Bullet();
      b.x = mouseX - 25;
      b.y = mouseY - 25;
      arrayBullets.add(b);
    }
    for (int i = 0; i < arrayBullets.size(); i++) {
      Bullet b = arrayBullets.get(i);
      b.y-=bulletTime;
      b.displayBullets();

      // for(int i = 0; i < arrayAliensa.size; i++) {
      //   Aliena a = arrayAliensa.get(i);
      for (Aliena a: arrayAliensa) {
        if (isColliding(b.x, b.y, bullets.width, bullets.height, 
        a.a, a.b, alien1.width, alien1.height)) {
          shotA = true;
        }
      }
      for (Alienb bb: arrayAliensb) {
        if (isColliding(b.x, b.y, bullets.width, bullets.height, 
        bb.a, bb.b, alien2.width, alien2.height)) {
          shotB = true;
        }
      }
      for (Alienc c: arrayAliensc) {
        if (isColliding(b.x, b.y, bullets.width, bullets.height, 
        c.a, c.b, alien3.width, alien3.height)) {
          shotC = true;
        }
      }
      if (b.y < 0) {
        arrayBullets.remove(i);
        i--;
      }
      else if (shotA==true) {
        arrayBullets.remove(i);
        //i--;
        score+=1;
      }
      else if (shotB==true) {
        arrayBullets.remove(i);
        //i--;
        score+=2;
      }
      else if (shotC==true) {
        arrayBullets.remove(i);
        //i--;
        score+=3;
      }
    }
    if (frameCount%50==0) {
      if (random(0, 3)<1) {
        Aliena a = new Aliena();
        a.a = random(50, 450); 
        a.b = 0;
        arrayAliensa.add(a);
      }
      else if (random(0, 3)>2) {
        Alienb bb = new Alienb();
        bb.a = random(50, 450); 
        bb.b = 0;
        arrayAliensb.add(bb);
      }
      else {
        Alienc c = new Alienc();
        c.a = random(50, 450); 
        c.b = 0;
        arrayAliensc.add(c);
      }
    }
    for (int aaa = 0; aaa < arrayAliensa.size(); aaa++) {
      Aliena a = arrayAliensa.get(aaa);
      a.b+=alienTimea;
      a.displayA();
      if (a.b >height) {
        arrayAliensa.remove(aaa);
        aaa--;
        lives--;
      }
      if (shotA==true) {
        arrayAliensa.remove(aaa);
        aaa--;
        shotA = false;
      }
    }
    for (int bbb = 0; bbb < arrayAliensb.size(); bbb++) {
      Alienb bb = arrayAliensb.get(bbb);
      bb.b+=alienTimeb;
      bb.displayB();
      if (bb.b >height) {
        arrayAliensb.remove(bbb);
        lives--;
      }
      if (shotB==true) {
        arrayAliensb.remove(bbb);
        bbb--;
        shotB = false;
      }
    }
    for (int ccc = 0; ccc < arrayAliensc.size(); ccc++) {
      Alienc c = arrayAliensc.get(ccc);
      c.b+=alienTimec;
      c.displayC();
      if (c.b > height) {
        arrayAliensc.remove(ccc);
        ccc--;
        lives--;
      }
      if (shotC==true) {
        arrayAliensc.remove(ccc);
        ccc--;
        shotC = false;
      }
      if (lives<=0) {
        state="game over";
      }
    }
    if (timeFrame<=0) {
      state = "stagescreen";
    }
  }
}
// detects whether rect 1 and rect 2 are overlapping
boolean isColliding(float x1, float y1, float w1, float h1, float x2, float y2, float w2, float h2) {
  return (x2 - x1 < w1 && x1 - x2 < w2) && (y2 - y1 < h1 && y1 - y2 < h2);
}