class_name PlanetSetups
extends RefCounted

# Registry of authored PlanetSetup resources. Deliberately scans
# res://PlanetSetups/ at first use instead of a hardcoded preload
# dictionary (contrast PlanetDefinitions.gd), so dropping a new .tres in
# that folder is the only step needed to add a setup - the map editor
# (#48) writes there directly.

const SETUPS_DIR: String = "res://PlanetSetups"
# Compared against get_script() rather than an `is PlanetSetup` check - the
# same load-order hazard as PlanetSurfaceController's setup_host: a global
# class_name identifier can be looked up before an import pass has
# registered it, while a direct script preload never depends on that cache.
const PLANET_SETUP_SCRIPT: Script = preload("res://PlanetSetup.gd")

static var _all: Array = []
static var _scanned: bool = false


static func _ensure_scanned() -> void:
	if _scanned:
		return
	_scanned = true
	var dir: DirAccess = DirAccess.open(SETUPS_DIR)
	if dir == null:
		return
	dir.list_dir_begin()
	var file_name: String = dir.get_next()
	while file_name != "":
		if not dir.current_is_dir() and file_name.ends_with(".tres"):
			var res: Resource = load(SETUPS_DIR + "/" + file_name)
			if res != null and res.get_script() == PLANET_SETUP_SCRIPT:
				_all.append(res)
		file_name = dir.get_next()
	dir.list_dir_end()


static func rescan() -> void:
	# The map editor calls this after saving so a freshly written setup is
	# visible without restarting the process.
	_all = []
	_scanned = false
	_ensure_scanned()


static func all() -> Array:
	_ensure_scanned()
	return _all


static func setups_for_profile(profile_id: String) -> Array:
	var result: Array = []
	for setup in all():
		if setup.surface_profile_id == profile_id:
			result.append(setup)
	return result


static func setup_for_planet(planet_id: String, profile_id: String) -> Resource:
	# Same pattern as WorldGen.planet_data_at_chunk: seeded purely from the
	# planet's own stable id, so the same planet always resolves to the
	# same setup from anywhere, with nothing stored.
	var candidates: Array = setups_for_profile(profile_id)
	if candidates.is_empty():
		return null
	var rng: RandomNumberGenerator = RandomNumberGenerator.new()
	rng.seed = hash(planet_id)
	return candidates[rng.randi() % candidates.size()]