class Alien extends Phaser.Sprite {

	constructor(initialX, initialY, onFiredFunction, onEscapedFunction) {
		super();

		this.isActivated = false;
		this.isOnstage = false;
		this.speedGrowing = Alien.DEFAULT_SPEED_SEC;

		this.initialX = initialX;
		this.initialY = initialY;

		this.onFiredFunction = onFiredFunction;
		this.onEscapedFunction = onEscapedFunction;

		Phaser.Sprite.call(this, game, this.initialX, this.initialY, 'alien_normal');
		this.anchor.set(0.5);
		// this.scale.set(Alien.MAX_SCALE);
		this.setOnInitialPosition();


		this.inputEnabled = true;
		this.events.onInputOut.add(this.onOut, this);
		this.events.onInputOver.add(this.onOver, this);
		this.events.onInputDown.add(this.onDown, this);

		game.add.existing(this);
	}

	onOut() {
		if(!this.isActivated)
			return;
	}

	onOver() {
		if(!this.isActivated)
			return;
	}

	onDown() {
		if(!this.isActivated)
			return;

		if(typeof this.onFiredFunction !== "undefined")
			this.onFiredFunction(this);
	}


	setActive(isActivated) {
		let beforeState = this.isActivated;
		this.isActivated = isActivated;

		if(beforeState && !this.isActivated) {
			this.shutdown();
		}
	}

	shutdown() {
		if(typeof this.tweenScaleUp !== "undefined") {
			this.tweenScaleUp.stop();
			this.tweenScaleUp = null;
		}
		if(typeof this.tweenScaleDown !== "undefined") {
			this.tweenScaleDown.stop();
			this.tweenScaleDown = null;
		}

		this.scale.set(0);
	}

	setOnInitialPosition() {
		this.x = this.initialX;
		this.y = this.initialY;
		this.scale.set(Alien.MAX_SCALE);
	}

	goOnstage() {
		// set random position
		let SPAWN_BOX_LEFT		= 100;
		let SPAWN_BOX_WIDTH		= game.world.width - 200;
		let SPAWN_BOX_TOP		= 300;
		let SPAWN_BOX_HEIGHT	= game.world.height - 400;

		this.x = SPAWN_BOX_LEFT + Math.random() * SPAWN_BOX_WIDTH;
		this.y = SPAWN_BOX_TOP + Math.random() * SPAWN_BOX_HEIGHT;

		// start scale tween animation
		this.shutdown();

		this.tweenScaleUp = game.add.tween(this.scale)
			.to( { x: Alien.MAX_SCALE, y: Alien.MAX_SCALE }, Alien.DEFAULT_SPEED_SEC, Phaser.Easing.Linear.None, false);
		this.tweenScaleDown = game.add.tween(this.scale)
			.to( { x: 0, y: 0 }, Alien.DEFAULT_SPEED_SEC, Phaser.Easing.Linear.None, false);
		this.tweenScaleUp.chain(this.tweenScaleDown);
		this.tweenScaleDown.onComplete.addOnce(this.onEscaped, this);
		this.tweenScaleUp.start();
	}

	onEscaped() {
		if(!this.isActivated)
			return;

		if(typeof this.onEscapedFunction !== "undefined")
			this.onEscapedFunction(this);
	}

}

Alien.DEFAULT_SPEED_SEC		= 3000;
Alien.MAX_SCALE				= 3;