extends Node2D

var s_max_speed = 4
var s_force_magnitude = 0.05
var s_turn_speed = deg2rad(3)

var g_destination = null
var g_velocity = Vector2(2, 0)
var g_acceleration = Vector2.ZERO

func _ready():
	pass

func _physics_process(delta):

	g_velocity += g_acceleration
	g_velocity = _clamp_vector(g_velocity, s_max_speed)
	g_acceleration = Vector2.ZERO

	position += g_velocity
	_move_towards(g_destination)

func _move_towards(location):

	# No destination assigned
	if g_destination == null:
		return

	# Get direction vector towards the target
	var desired_velocity = g_destination - global_position
	desired_velocity = desired_velocity.normalized()
	desired_velocity *= s_max_speed

	var steering_force = self._clamp_vector(desired_velocity, s_force_magnitude)
	g_velocity += steering_force

	var dir = g_velocity.angle_to(location)
	rotation = lerp_angle(rotation, dir, 0.1)

func steer_towards(location):
	g_destination = location

func _clamp_vector(vec, max_magnitude):
	var current_mag = vec.length()
	var multiplier = 1.0 \
		if current_mag <= max_magnitude else max_magnitude/current_mag

	return Vector2(vec.x * multiplier, vec.y * multiplier)