extends Node2D

# #116: draws the repair drones GameState is simulating, and only while they
# are somewhere the player could see them.
#
# Same arrangement as TransporterField, and for the same reason: the
# simulation is authoritative and the visuals are optional, so a repair run
# happening far away costs nothing but still puts the building back together.
# Position comes from the very same `progress` that decides when the repair
# actually lands.

@export var visible_radius: float = 2600.0

@onready var fleet: Node2D = get_node("../Fleet")

var drone_scene: PackedScene = preload("res://logistics/RepairDrone.tscn")
# index into GameState.repair_drones -> live node
var active: Dictionary = {}


func _process(_delta: float) -> void:
	var centre: Vector2 = fleet.get_centroid()

	for i in range(GameState.repair_drones.size()):
		var drone: Dictionary = GameState.repair_drones[i]
		# An idle drone is parked inside its workshop's own art; drawing it
		# there adds a dot sitting on a building rather than a vessel doing
		# something.
		if String(drone.state) == GameState.DRONE_IDLE:
			_despawn(i)
			continue
		var pos: Vector2 = GameState.repair_drone_position(drone)
		if pos.distance_to(centre) > visible_radius:
			_despawn(i)
			continue

		var node: Node2D = active.get(i)
		if node == null or not is_instance_valid(node):
			node = drone_scene.instantiate()
			get_parent().add_child(node)
			active[i] = node

		var previous: Vector2 = node.position
		node.position = pos
		node.set_laden(int(drone.carrying) > 0)
		var travel: Vector2 = pos - previous
		if travel.length() > 0.5:
			node.rotation = travel.angle() + PI / 2.0

	for key in active.keys():
		if key >= GameState.repair_drones.size():
			_despawn(key)


func _despawn(index: int) -> void:
	var node: Node2D = active.get(index)
	if node != null and is_instance_valid(node):
		node.queue_free()
	active.erase(index)