class_name AIController
extends Node

@export var standoff_distance := 30.0     # throttle down inside this
@export var fire_range := 120.0           # open fire inside this
@export var full_rudder_angle_deg := 20.0 # bearing error at which rudder saturates

var _boat: Boat
var _target: Boat  # node reference — shift-safe; never store a position


func _ready() -> void:
	_boat = get_parent() as Boat


func _physics_process(_delta: float) -> void:
	if _boat == null:
		return
	if _player_has_boat():
		return  # player possessed us — write nothing, resume when they leave

	if not is_instance_valid(_target):
		_target = _pick_target()
	if _target == null:
		_boat.desired_throttle = 0.0
		_boat.steer_input = 0.0
		_boat.aim_point = null  # stow turrets, per the aim contract
		_boat.fire_intents[0] = false
		return

	# All geometry computed fresh this tick — origin-shift safe.
	var to_target: Vector3 = _target.global_position - _boat.global_position
	to_target.y = 0.0
	var distance := to_target.length()

	var forward := -_boat.global_basis.z
	forward.y = 0.0

	var bearing_error := forward.signed_angle_to(to_target, Vector3.UP)
	_boat.steer_input = clampf(
		bearing_error / deg_to_rad(full_rudder_angle_deg), -1.0, 1.0)

	_boat.desired_throttle = 1.0 if distance > standoff_distance else 0.2

	_boat.aim_point = _target.global_position
	_boat.fire_intents[0] = distance < fire_range


func _player_has_boat() -> bool:
	var pc := get_tree().get_first_node_in_group(&"player_controllers") as PlayerController
	return pc != null and pc.current_controlled == _boat


func _pick_target() -> Boat:
	var best: Boat = null
	var best_d := INF
	for node in get_tree().get_nodes_in_group(&"boats"):
		var other := node as Boat
		if other == null or other == _boat:
			continue
		var d := _boat.global_position.distance_squared_to(other.global_position)
		if d < best_d:
			best_d = d
			best = other
	return best