var CAMERA_OFFSET_ANGLE = 0.0;
var CAMERA_OFFSET_RADIUS = 18.0;
var CAMERA_OFFSET_HEIGHT = 10.0;

class PlayerCamera extends Entity {
  constructor(target) {
    super();
    this.target = target;

    this.position = this.add(POSITION);
    this.add(CAMERA);

    this.update();
  }

  update() {
    var targetPosition = this.target.position.getLocalPosition();

    var eyeX = (
      targetPosition.x + Math.cos(CAMERA_OFFSET_ANGLE) * CAMERA_OFFSET_RADIUS
    );
    var eyeY = (
      targetPosition.y + CAMERA_OFFSET_HEIGHT
    );
    var eyeZ = (
      targetPosition.z + Math.sin(CAMERA_OFFSET_ANGLE) * CAMERA_OFFSET_RADIUS
    );

    this.position.lookAt(
      eyeX, eyeY, eyeZ,
      targetPosition.x, targetPosition.y, targetPosition.z,
      0.0, 1.0, 0.0
    );
  }

  dispose() {
    this.target = null;
  }
}

module.exports = PlayerCamera;