/****
* Classes
****/
// Bullet class
var Bullet = Container.expand(function () {
  var self = Container.call(this);
  var bulletGraphics = self.attachAsset('bullet', {
    anchorX: 0.5,
    anchorY: 0.5
  });
  self.speed = -10;
  self.move = function () {
    self.y += self.speed;
  };
});
// Assets will be automatically created based on usage in the code.
// Player class
var Player = Container.expand(function () {
  var self = Container.call(this);
  var playerGraphics = self.attachAsset('player', {
    anchorX: 0.5,
    anchorY: 0.5
  });
  self.speed = 5;
  self.move = function (direction) {
    if (direction === 'left' && self.x > 0) {
      self.x -= self.speed;
    } else if (direction === 'right' && self.x < 2048) {
      self.x += self.speed;
    }
  };
});
// Zombie class
var Zombie = Container.expand(function () {
  var self = Container.call(this);
  var zombieGraphics = self.attachAsset('zombie', {
    anchorX: 0.5,
    anchorY: 0.5
  });
  self.speed = 2;
  self.move = function () {
    self.y += self.speed;
  };
});

/****
* Initialize Game
****/
var game = new LK.Game({
  backgroundColor: 0x000000 // Init game with black background 
});

/****
* Game Code
****/
var player = game.addChild(new Player());
player.x = 1024; // Center horizontally
player.y = 2500; // Near bottom
var zombies = [];
var bullets = [];
var score = 0;
var scoreTxt = new Text2(score.toString(), {
  size: 150,
  fill: "#ffffff"
});
LK.gui.top.addChild(scoreTxt);
// Create zombies at intervals
var zombieInterval = LK.setInterval(function () {
  var zombie = new Zombie();
  zombie.x = Math.random() * 2048; // Random horizontal position
  zombie.y = 0; // Start from top
  zombies.push(zombie);
  game.addChild(zombie);
}, 2000);
// Touch event to move player and shoot bullets
game.on('down', function (obj) {
  var pos = obj.event.getLocalPosition(game);
  if (pos.x < 1024) {
    player.move('left');
  } else {
    player.move('right');
  }
  var bullet = new Bullet();
  bullet.x = player.x;
  bullet.y = player.y;
  bullets.push(bullet);
  game.addChild(bullet);
});
// Game tick
LK.on('tick', function () {
  // Move zombies
  for (var i = zombies.length - 1; i >= 0; i--) {
    zombies[i].move();
    if (zombies[i].y > 2732) {
      // Off screen
      zombies[i].destroy();
      zombies.splice(i, 1);
    }
  }
  // Move bullets
  for (var j = bullets.length - 1; j >= 0; j--) {
    bullets[j].move();
    if (bullets[j].y < 0) {
      // Off screen
      bullets[j].destroy();
      bullets.splice(j, 1);
    }
  }
  // Check for bullet-zombie collisions
  for (var b = bullets.length - 1; b >= 0; b--) {
    for (var z = zombies.length - 1; z >= 0; z--) {
      if (bullets[b] && zombies[z] && bullets[b].intersects(zombies[z])) {
        bullets[b].destroy();
        bullets.splice(b, 1);
        zombies[z].destroy();
        zombies.splice(z, 1);
        score += 1;
        scoreTxt.setText(score.toString());
        break;
      }
    }
  }
});