class_name Projectile
extends RigidBody3D

var damage := 0.0        # set by launch(), read by whatever we hit
var _time_left := 10.0

func _ready() -> void:
	add_to_group("shift_with_origin")
	body_entered.connect(_on_body_entered)

## Call after add_child(). Configures this projectile from a def and sends it flying.
func launch(def: AmmoDef, muzzle: Transform3D, speed_scale := 1.0) -> void:
	damage = def.damage
	gravity_scale = def.gravity_scale
	_time_left = def.lifetime
	global_transform = muzzle
	linear_velocity = -muzzle.basis.z * def.muzzle_speed * speed_scale
	reset_physics_interpolation()

func _physics_process(delta: float) -> void:
	if Vector3.UP.cross(linear_velocity).length_squared() > 0.01:
		look_at(global_position + linear_velocity)

	_time_left -= delta
	if _time_left <= 0.0:
		queue_free()

func _on_body_entered(body: Node) -> void:
	if body.has_method("take_damage"):
		body.take_damage(damage)
	queue_free()