spaceship/BuildingField.gd

extends Node2D

# Rebuilds every player-placed structure from GameState when the space
# scene loads, and answers "is the fleet standing on one?".
#
# Buildings live in GameState rather than in the scene because Main.tscn is
# torn down and recreated on every trip to a planet's surface - anything
# kept only as a node would be lost on the first landing.

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

var building_scene: PackedScene = preload("res://Building.tscn")
var spawned: Array = []
# Whether the fleet was already standing on the mothership last frame - see
# the edge-triggered delivery in _process().
var _was_on_mothership: bool = false


func _ready() -> void:
	rebuild_all()


func _process(_delta: float) -> void:
	# Unloading the fleet's hold (#14). Done here because this is the node
	# that already knows where the buildings are and already answers "is the
	# fleet standing on one?" - and it uses the fleet CENTROID, the same
	# stable single-number test Planet and Building already use, rather than
	# per-ship collision that flickers as ships jostle in formation.
	# EDGE-triggered on arrival, not continuous. Delivering every frame the
	# fleet is parked on the mothership would make withdrawing impossible:
	# ore loaded into the hold at the mothership (#17) would be banked again
	# the very next frame, and the button would look broken.
	var under: Node2D = get_building_fleet_is_on()
	var on_mothership: bool = under != null \
		and under.building_type == GameState.BUILDING_MOTHERSHIP
	if on_mothership and not _was_on_mothership and GameState.fleet_cargo > 0:
		GameState.deliver_cargo()
	_was_on_mothership = on_mothership


func rebuild_all() -> void:
	for b in spawned:
		if is_instance_valid(b):
			b.queue_free()
	spawned.clear()
	for record in GameState.buildings:
		_spawn(record)


func place(type: String, at_position: Vector2) -> void:
	GameState.add_building(type, at_position)
	_spawn(GameState.buildings[-1])


func get_building_fleet_is_on() -> Node2D:
	var centre: Vector2 = fleet.get_centroid()
	for b in spawned:
		if is_instance_valid(b) and b.position.distance_to(centre) <= b.interact_radius:
			return b
	return null


func _spawn(record: Dictionary) -> void:
	var b: Node2D = building_scene.instantiate()
	b.position = record.position
	b.building_type = record.type
	b.building_id = int(record.get("id", 0))
	# Deferred for the same reason as the other field spawners: this can run
	# from inside a parent's _ready() chain, where a direct add_child() is
	# rejected while the tree is still setting up children.
	get_parent().add_child.call_deferred(b)
	spawned.append(b)