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://surface/PlanetSetup.gd")


# The name to LOAD for a directory entry, or "" for an entry that is not a
# setup at all.
#
# An export does not ship the .tres. Text resources are converted to binary
# and the pack carries "<name>.tres.remap" beside them - the remap points at
# the converted file, and ResourceLoader follows it when asked for the
# ORIGINAL path. So a scan that matches on ".tres" finds every setup when run
# from source and none at all in an exported build, which is what emptied
# every planet of its garrison on the web version: no setups, no enemies, and
# nothing logged anywhere to say so.
#
# The suite runs from source, so nothing here can catch that by running the
# game - this function exists to be tested directly.
static func setup_file_name(entry: String) -> String:
	var name: String = entry
	if name.ends_with(".remap"):
		name = name.get_basename()
	if name.ends_with(".tres") or name.ends_with(".res"):
		return name
	return ""

static var _all: Array = []
static var _scanned: bool = false
# Which setup each planet drew, once it has drawn one. See setup_for_planet.
static var _assigned: Dictionary = {}


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()
	var seen: Dictionary = {}
	while file_name != "":
		var setup_file: String = setup_file_name(file_name)
		if not dir.current_is_dir() and setup_file != "" and not seen.has(setup_file):
			seen[setup_file] = true
			# CACHE_MODE_REPLACE, not a plain load(). Godot caches resources by
			# path, so after the map editor saved a setup this handed back the
			# CACHED copy - still holding the values from before the save. The
			# editor called rescan() and the pool dutifully re-served the stale
			# data, which is what "I changed the research points and it was not
			# saved" actually was: the file on disk was correct all along.
			#
			# REPLACE rather than IGNORE deliberately: it refreshes the
			# existing instance in place instead of minting a new one, so
			# object identity across a rescan survives - which the per-planet
			# map assignments depend on (see setup_for_planet).
			var res: Resource = ResourceLoader.load(SETUPS_DIR + "/" + setup_file,
				"", ResourceLoader.CACHE_MODE_REPLACE)
			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()
	# Assignments are PRUNED, not cleared. Clearing them would undo the whole
	# point of remembering: saving one map in the editor would silently re-deal
	# every planet the player had already visited. What has to go is only the
	# entries pointing at a setup that no longer exists - a deleted map must
	# not stay pinned to a planet.
	var live: Dictionary = {}
	for setup in _all:
		live[setup] = true
	for key in _assigned.keys():
		if not live.has(_assigned[key]):
			_assigned.erase(key)


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


static func find_by_id(setup_id: String) -> Resource:
	for setup in all():
		if String(setup.setup_id) == setup_id:
			return setup
	return null


static func path_for_id(setup_id: String) -> String:
	# The file a setup actually LIVES in, which is not reliably
	# "PlanetSetups/<setup_id>.tres". Authored resources carry whatever
	# filename they were created with, and at least one shipped setup has an
	# id that differs from its filename outright (ResearchLabSetup.tres holds
	# setup_id "research_lab_1"). Deriving the path from the id instead of
	# asking the resource broke two things at once: deleting such a setup
	# looked for a file that does not exist and silently refused, and saving
	# one wrote a SECOND file under the derived name, leaving the original
	# behind with the old contents - which reads exactly like "my change was
	# not saved", because the stale twin is still in the pool.
	var setup: Resource = find_by_id(setup_id)
	if setup != null and String(setup.resource_path) != "":
		return String(setup.resource_path)
	return "%s/%s.tres" % [SETUPS_DIR, setup_id]


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)
	# Sorted by id, because the order they arrive in is whatever order the
	# filesystem listed them in - which is not something to seed a choice
	# with. The pick below indexes into this array, so an unstable order
	# means the same planet can land on a different map from one run to the
	# next, and the "this is MY planet's layout" illusion goes with it.
	result.sort_custom(func(a, b): return String(a.setup_id) < String(b.setup_id))
	return result


static func setup_for_planet(planet_id: String, profile_id: String) -> Resource:
	# Every planet gets a map of its own type, drawn at random, and keeps it.
	#
	# The draw is seeded purely from the planet's own stable id - same pattern
	# as WorldGen.planet_data_at_chunk - so leaving a planet and coming back
	# lands on the same layout without anything having to be saved.
	#
	# The result is then remembered anyway, because the seed alone is not
	# quite enough: the pool it indexes into changes the moment the map editor
	# saves a new setup, which would silently re-deal every planet in the
	# middle of a session. Once a planet has been visited its map is pinned
	# for as long as the process lives.
	#
	# Keyed on the profile too, not the planet alone: the memo must never be
	# able to hand back a gas map for a rocky query just because that planet
	# id was seen first.
	var key: String = "%s|%s" % [planet_id, profile_id]
	var remembered: Resource = _assigned.get(key)
	if remembered != null:
		return remembered

	var candidates: Array = setups_for_profile(profile_id)
	if candidates.is_empty():
		return null
	var rng: RandomNumberGenerator = RandomNumberGenerator.new()
	rng.seed = hash(planet_id)
	var chosen: Resource = candidates[rng.randi() % candidates.size()]
	_assigned[key] = chosen
	return chosen