/// <summary>
        /// Sets the new target building
        /// </summary>
        /// <param name="building"> Target building </param>
        void setTargetBuilding(BuildingEntity building)
        {
            building.OnDeath += (a, b) =>
            {
                if (targetBuilding != null)
                {
                    targetBuilding.Delete();
                }

                hasTarget = attacking = false;
            };

            targetBuilding = building;
        }
        /// <summary>
        /// Update enemy logic
        /// </summary>
        public override void Update(GameTime gameTime)
        {
            // update animations
            updateAnimations(gameTime);

            float delta = (float)gameTime.ElapsedGameTime.TotalSeconds;

            // if the enemy doesn't have a target and isn't entering,
            // find a new target building
            if (!isEntering && !hasTarget)
            {
                aquireNewTargetBuilding();
            }

            float speed = delta * walkSpeed;

            // follow target path if the enemy isn't attacking
            if (!attacking && path.Count > 1)
            {
                // get the position of our current target
                var target = world.Grid[path[0]].Position +
                             properties.TargetNodeOffset;

                // set our enemy walking
                currentAnimation = "Walk";
                shadowAnimation  = "ShadowWalk";

                if (Vector2.Distance(target, position) <= speed)
                {
                    // we aren't entering anymore
                    isEntering = false;

                    path.RemoveAt(0);

                    // new node
                    var node = world.Grid[path[0]];

                    // new target position
                    var newTarget = node.Position +
                                    properties.TargetNodeOffset;

                    if (node.Occupant != null &&
                        node.Occupant.BuildingType == Building.Barricade)
                    {
                        var tmpBuilding = targetBuilding;

                        targetBuilding = node.Occupant;
                        attacking      = true;

                        targetBuilding.OnDeath += delegate
                        {
                            if (targetBuilding != null)
                            {
                                targetBuilding.Delete();
                            }

                            targetBuilding = tmpBuilding;

                            attacking = false;
                            hasTarget = true;

                            setTargetPosition(newTarget);
                        };
                    }
                    else
                    {
                        // set the new target position
                        setTargetPosition(newTarget);
                    }

                    // reached the destination, start attacking
                    if (path.Count == 1)
                    {
                        attacking = true;

                        // set our idle animation
                        currentAnimation = "Idle";
                        shadowAnimation  = "ShadowIdle";

                        // set our idle animation frame to the frame
                        // prescribed by the building attack node
                        setIdleFrame(destinationFrame);
                    }
                }
            }
            else if (attacking)
            {
                lastAttacked -= gameTime.ElapsedGameTime;

                if (lastAttacked <= TimeSpan.Zero)
                {
                    lastAttacked = attackInterval;

                    // attack the target building, we've reached our attack
                    // interval
                    attackTargetBuilding();
                }

                // make sure we're idle
                velocity = Vector2.Zero;
            }

            // move the enemy based on our velocity
            position += velocity * speed;

            // update enemy bullet logic
            checkBulletCollision();
        }