extends SceneTree

var failures := 0


func _initialize() -> void:
	var service = load("res://scripts/autoload/block_session_service.gd").new()
	var question := _question(9)
	var prepared: Dictionary = service._prepare_question_choices(question.duplicate(true))
	_check_presented(prepared)

	var stable: Dictionary = service._prepare_question_choices(prepared.duplicate(true))
	_assert(stable.get("presented_choices", []) == prepared.get("presented_choices", []), "session choices must remain stable")

	var observed_sets := {}
	for iteration in range(40):
		var rerolled: Dictionary = service._prepare_question_choices(question.duplicate(true))
		_check_presented(rerolled)
		var ids := _ids(rerolled.get("presented_choices", []))
		ids.sort()
		observed_sets[",".join(ids)] = true
	_assert(observed_sets.size() > 1, "future sessions should be able to present different distractors")

	var legacy: Dictionary = service._prepare_question_choices(_question(5))
	_check_presented(legacy)
	_assert(_ids(legacy.get("presented_choices", [])).size() == 5, "legacy five-choice questions must show all choices")
	service.free()
	quit(1 if failures > 0 else 0)


func _question(count: int) -> Dictionary:
	var choices: Array = []
	for index in range(count):
		choices.append({"id": String.chr(65 + index), "text": "Choice %d" % index})
	return {"choices": choices, "correct_choice_id": "A"}


func _check_presented(question: Dictionary) -> void:
	var ids := _ids(question.get("presented_choices", []))
	_assert(ids.size() == 5, "exactly five choices must be presented")
	_assert(ids.has("A"), "the correct answer must be presented")
	var unique := {}
	for id in ids:
		unique[id] = true
	_assert(unique.size() == ids.size(), "presented choices must be unique")


func _ids(choices: Array) -> Array:
	var ids: Array = []
	for choice in choices:
		ids.append(str(choice.get("id", "")))
	return ids


func _assert(condition: bool, message: String) -> void:
	if condition:
		return
	failures += 1
	push_error(message)