/****
* Classes
****/
// Enemy class for targets
var Enemy = Container.expand(function () {
  var self = Container.call(this);
  var enemyGraphics = self.attachAsset('enemy', {
    anchorX: 0.5,
    anchorY: 0.5
  });
  self.speed = 2;
  self.move = function () {
    self.y += self.speed;
  };
});
// Assets are automatically created based on usage in the code.
// Bullet class for bullets fired by the player
var PlayerBullet = Container.expand(function () {
  var self = Container.call(this);
  var bulletGraphics = self.attachAsset('playerBullet', {
    anchorX: 0.5,
    anchorY: 0.5
  });
  self.speed = -10;
  self.move = function () {
    self.y += self.speed;
  };
});

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

/****
* Game Code
****/
var playerBullets = [];
var enemies = [];
var spawnEnemyInterval = 120; // Frames until next enemy spawns
var enemySpawnTimer = 0;
// Create player
var player = game.addChild(new Container());
player.x = 1024; // Center horizontally
player.y = 2500; // Near bottom
// Function to spawn enemies
function spawnEnemy() {
  var enemy = new Enemy();
  enemy.x = Math.random() * 2048; // Random position across the width
  enemy.y = 0; // Start at the top
  enemies.push(enemy);
  game.addChild(enemy);
}
// Function to fire a bullet
function fireBullet() {
  var bullet = new PlayerBullet();
  bullet.x = player.x;
  bullet.y = player.y;
  playerBullets.push(bullet);
  game.addChild(bullet);
}
// Touch event to move player and fire bullets
game.on('down', function (obj) {
  var pos = obj.event.getLocalPosition(game);
  player.x = pos.x;
  fireBullet();
});
// Main game loop
LK.on('tick', function () {
  // Move bullets
  for (var i = playerBullets.length - 1; i >= 0; i--) {
    playerBullets[i].move();
    if (playerBullets[i].y < 0) {
      // Remove bullets that go off screen
      playerBullets[i].destroy();
      playerBullets.splice(i, 1);
    }
  }
  // Move enemies
  for (var j = enemies.length - 1; j >= 0; j--) {
    enemies[j].move();
    if (enemies[j].y > 2732) {
      // Remove enemies that go off screen
      enemies[j].destroy();
      enemies.splice(j, 1);
    }
  }
  // Check for collisions
  for (var b = playerBullets.length - 1; b >= 0; b--) {
    for (var e = enemies.length - 1; e >= 0; e--) {
      if (playerBullets[b] && enemies[e] && playerBullets[b].intersects(enemies[e])) {
        // Destroy both bullet and enemy on collision
        playerBullets[b].destroy();
        playerBullets.splice(b, 1);
        enemies[e].destroy();
        enemies.splice(e, 1);
        break; // Exit loop after collision to avoid errors
      }
    }
  }
  // Spawn enemies
  if (enemySpawnTimer <= 0) {
    spawnEnemy();
    enemySpawnTimer = spawnEnemyInterval;
  } else {
    enemySpawnTimer--;
  }
});