Add variable question distractor pools

scripts/autoload/block_session_service.gd

@@ -30,6 +30,8 @@ func start_block(selected_system: String, block_size: int, selected_mode: String
 	mode = selected_mode
 	session_kind = "block"
 	active_questions = QuestionBankService.build_block(selected_system, block_size)
+	for index in range(active_questions.size()):
+		active_questions[index] = _prepare_question_choices(active_questions[index])
 	answers.clear()
 	answers.resize(active_questions.size())
 	current_index = 0
@@ -293,10 +295,38 @@ func _draw_core_question() -> Dictionary:
 		var candidate: Dictionary = core_question_pool[index]
 		if str(candidate.get("id", "")) != last_id or core_question_pool.size() == 1:
 			core_question_pool.remove_at(index)
-			return candidate.duplicate(true)
+			return _prepare_question_choices(candidate.duplicate(true))
 	return {}
 
 
+func _prepare_question_choices(question: Dictionary) -> Dictionary:
+	var existing: Array = question.get("presented_choices", [])
+	if not existing.is_empty():
+		return question
+
+	var all_choices: Array = question.get("choices", []).duplicate(true)
+	var correct_id := str(question.get("correct_choice_id", ""))
+	var correct_choice: Dictionary = {}
+	var distractors: Array = []
+	for choice in all_choices:
+		if typeof(choice) != TYPE_DICTIONARY:
+			continue
+		if str(choice.get("id", "")) == correct_id:
+			correct_choice = choice
+		else:
+			distractors.append(choice)
+
+	distractors.shuffle()
+	var presented: Array = distractors.slice(0, min(4, distractors.size()))
+	if not correct_choice.is_empty():
+		presented.append(correct_choice)
+	elif not all_choices.is_empty():
+		presented = all_choices.slice(0, min(5, all_choices.size()))
+	presented.shuffle()
+	question["presented_choices"] = presented
+	return question
+
+
 func _build_core_question_pool() -> Array:
 	var pool: Array = []
 	var profile := ProfileService.get_profile()