extends Node3D

## NS-16: walkable ground ray pick. Emits world target for MoveCommand; camera wired from main.
## (No `class_name` so headless/CI can load the project before `.godot` import exists.)

signal target_chosen(world: Vector3)

## Fallback when `Viewport.get_camera_3d()` is null (e.g. some editor setups). Set from `main.gd`
## in `_ready`.
var fallback_camera: Camera3D


func _input(event: InputEvent) -> void:
	if event is InputEventMouseButton:
		var mb := event as InputEventMouseButton
		if mb.button_index == MOUSE_BUTTON_LEFT and mb.pressed:
			_try_pick(get_viewport().get_mouse_position())


func _try_pick(screen_pos: Vector2) -> void:
	var cam: Camera3D = get_viewport().get_camera_3d()
	if cam == null:
		cam = fallback_camera
	if cam == null:
		return

	var origin: Vector3 = cam.project_ray_origin(screen_pos)
	var ray_dir: Vector3 = cam.project_ray_normal(screen_pos)
	var to: Vector3 = origin + ray_dir * 2000.0
	var query := PhysicsRayQueryParameters3D.create(origin, to)
	query.collision_mask = 1
	var space: PhysicsDirectSpaceState3D = get_world_3d().direct_space_state
	var hit: Dictionary = space.intersect_ray(query)
	if hit.is_empty():
		return
	var collider: Variant = hit.get("collider")
	if not _collider_is_walkable(collider):
		return
	var hit_pos: Variant = hit.get("position")
	if hit_pos is Vector3:
		target_chosen.emit(hit_pos as Vector3)


func _collider_is_walkable(collider: Variant) -> bool:
	var n: Node = collider as Node
	while n:
		if n.is_in_group("walkable"):
			return true
		n = n.get_parent()
	return false