extends Node

## Loads modifier definitions and serves them by id.
##
## ⚠️ PROTOTYPE. This is scaffolding, not the real mod loader.
##
## What's wrong with it, to be fixed in Phase 3:
##   - DirAccess cannot walk into a PCK. This works in the editor and silently
##     returns NOTHING in an exported build. Needs a build-time manifest.
##   - No namespacing. Ids are bare strings, so two mods can collide.
##   - No mod.json, no api_version, no dependency resolution.
##   - Only reads content/official/. Doesn't touch user://mods/.
##
## Autoload name is ModRegistry (PascalCase), so call sites read as
## ModRegistry.get_by_id(...) rather than looking like a local variable.

const MODIFIER_DIR := "res://content/official/modifiers/"

var modifiers: Array[Modifier] = []
var _by_id: Dictionary = {}


func _ready() -> void:
	_load_from_folder(MODIFIER_DIR)
	_reindex()
	print("ModRegistry: loaded %d modifiers." % modifiers.size())


## Recursive, because each modifier now lives in its own folder:
##   modifiers/mjolnir/mjolnir.tres
func _load_from_folder(path: String) -> void:
	var dir := DirAccess.open(path)
	if dir == null:
		push_warning("ModRegistry: can't open %s" % path)
		return

	dir.list_dir_begin()
	var fname := dir.get_next()
	while fname != "":
		var full := path.path_join(fname)
		if dir.current_is_dir():
			if not fname.begins_with("."):
				_load_from_folder(full)
		elif fname.ends_with(".tres"):
			var res := load(full)
			if res is Modifier:
				modifiers.append(res)
			else:
				push_warning("ModRegistry: %s is not a Modifier" % full)
		fname = dir.get_next()
	dir.list_dir_end()


func _reindex() -> void:
	_by_id.clear()
	for m in modifiers:
		if m.id.is_empty():
			push_warning("ModRegistry: modifier with empty id, skipping.")
			continue
		if _by_id.has(m.id):
			push_warning("ModRegistry: duplicate id '%s'." % m.id)
		_by_id[m.id] = m


func get_by_id(id: String) -> Modifier:
	return _by_id.get(id)


## Pick `count` distinct modifiers, weighted by rarity.
func pick_random(count: int) -> Array[Modifier]:
	var pool := modifiers.duplicate()
	var chosen: Array[Modifier] = []
	count = mini(count, pool.size())

	for _i in count:
		var total := 0.0
		for m in pool:
			total += maxf(m.weight, 0.0001)

		var r := randf() * total
		var acc := 0.0
		var picked := 0
		for j in pool.size():
			acc += maxf(pool[j].weight, 0.0001)
			if r <= acc:
				picked = j
				break

		chosen.append(pool[picked])
		pool.remove_at(picked)   # distinct — don't offer the same one twice

	return chosen