Add post-answer review and per-question loading

scripts/ui/login_screen.gd

@@ -235,7 +235,6 @@ func _on_login_request_completed(result: int, response_code: int, _headers: Pack
 		String(response.get("role", "")),
 		String(response.get("exp", ""))
 	)
-	QuestionBankService.load_questions_from_api()
 	UISoundService.play_sound("correct")
 	password_input.text = ""
 	registration_password_input.text = ""

scripts/ui/question_player.gd

@@ -41,6 +41,7 @@ var timer_color_state := ""
 var pending_correct_advance := false
 var question_text_scale := 1.0
 var presented_choices: Array = []
+var awaiting_next_question := false
 
 var progress_label: Label
 var timer_label: Label
@@ -48,6 +49,8 @@ var player_stats_label: Label
 var stem_label: RichTextLabel
 var lead_label: Label
 var explanation_label: RichTextLabel
+var references_container: VBoxContainer
+var question_scroll: ScrollContainer
 var question_elo_label: Label
 var next_button: Button
 var skip_button: Button
@@ -107,6 +110,10 @@ func _ready() -> void:
 		QuestionBankService.question_report_submitted.connect(_on_question_report_submitted)
 	if not QuestionBankService.question_report_failed.is_connected(_on_question_report_failed):
 		QuestionBankService.question_report_failed.connect(_on_question_report_failed)
+	if not QuestionBankService.questions_changed.is_connected(_on_random_question_changed):
+		QuestionBankService.questions_changed.connect(_on_random_question_changed)
+	if not QuestionBankService.questions_load_failed.is_connected(_on_random_question_failed):
+		QuestionBankService.questions_load_failed.connect(_on_random_question_failed)
 
 	var top := HBoxContainer.new()
 	top.add_theme_constant_override("separation", 12)
@@ -212,15 +219,15 @@ func _ready() -> void:
 	question_panel.size_flags_vertical = Control.SIZE_EXPAND_FILL
 	add_child(question_panel)
 
-	var scroll := ScrollContainer.new()
-	scroll.size_flags_vertical = Control.SIZE_EXPAND_FILL
-	scroll.horizontal_scroll_mode = ScrollContainer.SCROLL_MODE_DISABLED
-	question_panel.add_child(scroll)
+	question_scroll = ScrollContainer.new()
+	question_scroll.size_flags_vertical = Control.SIZE_EXPAND_FILL
+	question_scroll.horizontal_scroll_mode = ScrollContainer.SCROLL_MODE_DISABLED
+	question_panel.add_child(question_scroll)
 
 	var content_margin := MarginContainer.new()
 	content_margin.size_flags_horizontal = Control.SIZE_EXPAND_FILL
 	content_margin.add_theme_constant_override("margin_right", 16)
-	scroll.add_child(content_margin)
+	question_scroll.add_child(content_margin)
 
 	question_content = VBoxContainer.new()
 	question_content.size_flags_horizontal = Control.SIZE_EXPAND_FILL
@@ -329,6 +336,11 @@ func _ready() -> void:
 	_set_scaled_rich_text(explanation_label, 17)
 	question_content.add_child(explanation_label)
 
+	references_container = VBoxContainer.new()
+	references_container.visible = false
+	references_container.add_theme_constant_override("separation", 6)
+	question_content.add_child(references_container)
+
 	var actions := HBoxContainer.new()
 	actions.add_theme_constant_override("separation", 10)
 	skip_button = Button.new()
@@ -341,6 +353,7 @@ func _ready() -> void:
 
 	next_button = Button.new()
 	next_button.text = "Submit"
+	next_button.tooltip_text = ""
 	next_button.custom_minimum_size = Vector2(140, 48)
 	next_button.size_flags_horizontal = Control.SIZE_EXPAND_FILL
 	Style.style_primary_button(next_button)
@@ -389,6 +402,7 @@ func on_show(_payload: Variant = null) -> void:
 
 
 func on_hide() -> void:
+	awaiting_next_question = false
 	_hide_report_modal(true)
 	_hide_labs_modal()
 
@@ -444,6 +458,7 @@ func _load_question() -> void:
 	flag_button.button_pressed = false
 	_refresh_toolbar_state()
 	explanation_label.visible = false
+	_clear_references()
 	question_elo_label.visible = false
 	question_elo_label.text = ""
 	next_button.text = "Submit"
@@ -489,13 +504,7 @@ func _load_question() -> void:
 		flagged = bool(saved_answer.get("flagged", false))
 		flag_button.button_pressed = flagged
 		_refresh_toolbar_state()
-		if BlockSessionService.mode == "Tutor":
-			_show_explanation()
-			next_button.text = "Next"
-		else:
-			_apply_saved_choice_state()
-			next_button.text = "Next"
-		next_button.disabled = false
+		_show_answer_review()
 		_update_question_elo_label(true)
 
 	_refresh_nav_palette()
@@ -628,6 +637,8 @@ func _toggle_eliminate_selected() -> void:
 
 
 func _submit_or_next() -> void:
+	if awaiting_next_question:
+		return
 	if pending_correct_advance:
 		return
 	if current_answer.is_empty():
@@ -649,6 +660,7 @@ func _submit_or_next() -> void:
 			if bool(result.get("is_correct", false)):
 				current_answer = answer
 				_update_question_elo_label(true)
+				_show_answer_review()
 				_trigger_correct_feedback()
 				return
 			_lock_wrong_choice(attempted_choice)
@@ -666,14 +678,58 @@ func _submit_or_next() -> void:
 			_presented_choice_ids()
 		)
 		current_answer = BlockSessionService.answer_current(selected_choice, eliminated, flagged)
-		if BlockSessionService.mode == "Tutor":
-			_show_explanation()
-			next_button.text = "Next"
-		else:
-			next_button.text = "Next"
-			_refresh_nav_palette()
+		_show_answer_review()
 	else:
-		_advance_or_finish()
+		if BlockSessionService.session_kind == "core":
+			_request_next_core_question()
+		else:
+			_advance_or_finish()
+
+
+func _request_next_core_question() -> void:
+	awaiting_next_question = true
+	next_button.text = "Loading..."
+	next_button.disabled = true
+	QuestionBankService.load_next_random_question(BlockSessionService.get_core_excluded_question_ids())
+
+
+func _on_random_question_changed() -> void:
+	if not awaiting_next_question or QuestionBankService.load_state != "ready":
+		return
+	var loaded_questions := QuestionBankService.get_all_questions()
+	if loaded_questions.is_empty():
+		_on_random_question_failed("No additional questions are available.")
+		return
+	if not BlockSessionService.append_core_question(loaded_questions[0]):
+		_on_random_question_failed("The next question could not be prepared.")
+		return
+	awaiting_next_question = false
+	_load_question()
+	UISoundService.play_sound("question")
+
+
+func _on_random_question_failed(message: String) -> void:
+	if not awaiting_next_question:
+		return
+	awaiting_next_question = false
+	next_button.text = "Retry"
+	next_button.disabled = false
+	next_button.tooltip_text = message
+
+
+func _show_answer_review() -> void:
+	_show_explanation()
+	_show_references(BlockSessionService.get_current_question().get("references", []))
+	next_button.text = "Next"
+	next_button.disabled = false
+	if skip_button != null:
+		skip_button.disabled = true
+		skip_button.visible = false
+	if question_scroll != null:
+		var review_target: Control = explanation_label
+		if references_container.visible:
+			review_target = references_container
+		question_scroll.call_deferred("ensure_control_visible", review_target)
 
 
 func _show_explanation() -> void:
@@ -698,6 +754,62 @@ func _show_explanation() -> void:
 	_refresh_nav_palette()
 
 
+func _show_references(raw_references: Variant) -> void:
+	_clear_references()
+	if typeof(raw_references) != TYPE_ARRAY:
+		return
+	var valid_references: Array = []
+	for reference in raw_references:
+		if typeof(reference) != TYPE_DICTIONARY:
+			continue
+		var url := str(reference.get("url", "")).strip_edges()
+		if not _is_safe_reference_url(url):
+			continue
+		valid_references.append(reference)
+	if valid_references.is_empty():
+		return
+
+	var heading := Label.new()
+	heading.text = "References"
+	_set_scaled_label(heading, 18, Style.TEXT)
+	references_container.add_child(heading)
+	for reference in valid_references:
+		var title := str(reference.get("title", "Reference")).strip_edges()
+		var publisher := str(reference.get("publisher", "")).strip_edges()
+		var url := str(reference.get("url", "")).strip_edges()
+		var link := LinkButton.new()
+		link.text = title if publisher == "" else "%s - %s" % [title, publisher]
+		link.tooltip_text = url
+		link.size_flags_horizontal = Control.SIZE_EXPAND_FILL
+		link.text_overrun_behavior = TextServer.OVERRUN_TRIM_ELLIPSIS
+		link.add_theme_color_override("font_color", Style.CYAN)
+		link.add_theme_color_override("font_hover_color", Style.MAGENTA)
+		link.set_meta("question_base_font_size", 16)
+		link.add_theme_font_size_override("font_size", _scaled_font_size(16))
+		link.pressed.connect(_open_reference_url.bind(url))
+		references_container.add_child(link)
+	references_container.visible = true
+
+
+func _clear_references() -> void:
+	if references_container == null:
+		return
+	for child in references_container.get_children():
+		references_container.remove_child(child)
+		child.queue_free()
+	references_container.visible = false
+
+
+func _is_safe_reference_url(url: String) -> bool:
+	return url.begins_with("https://") and url.length() > 8
+
+
+func _open_reference_url(url: String) -> void:
+	if not _is_safe_reference_url(url):
+		return
+	OS.shell_open(url)
+
+
 func _advance_or_finish() -> void:
 	if BlockSessionService.move_next():
 		_load_question()
@@ -757,11 +869,8 @@ func _trigger_wrong_feedback() -> void:
 
 func _trigger_correct_feedback() -> void:
 	UISoundService.play_sound("correct")
-	pending_correct_advance = true
-	correct_advance_delay = CORRECT_ADVANCE_DELAY_SECONDS
 	red_fog_time = 0.0
 	green_fog_time = FEEDBACK_FADE_SECONDS
-	next_button.disabled = true
 	if skip_button != null:
 		skip_button.disabled = true
 	for button in choice_buttons:
@@ -948,6 +1057,8 @@ func _refresh_scaled_fonts(node: Node) -> void:
 			node.add_theme_font_size_override("font_size", _scaled_font_size(base_size))
 		elif node is Button:
 			node.add_theme_font_size_override("font_size", _scaled_font_size(base_size))
+		elif node is LinkButton:
+			node.add_theme_font_size_override("font_size", _scaled_font_size(base_size))
 		elif node is RichTextLabel:
 			node.add_theme_font_size_override("normal_font_size", _scaled_font_size(base_size))
 			node.add_theme_font_size_override("bold_font_size", _scaled_font_size(base_size))
@@ -1543,7 +1654,7 @@ func _apply_saved_choice_state() -> void:
 		else:
 			choice_buttons[index].modulate = Color.WHITE
 
-	if pending_correct_advance:
+	if pending_correct_advance or bool(current_answer.get("is_correct", false)):
 		_apply_correct_answer_preview()
 
 	if followup_required:

scripts/ui/study_selector.gd

@@ -184,15 +184,9 @@ func _show_stage(stage_name: String) -> void:
 
 
 func _select_question_bank() -> void:
-	if QuestionBankService.has_questions() and QuestionBankService.load_state == "ready":
-		_start_question_bank()
-		return
-
 	pending_question_bank_launch = true
-	if QuestionBankService.load_state == "idle":
-		QuestionBankService.load_questions_from_api()
-	elif QuestionBankService.load_state == "failed":
-		QuestionBankService.retry_now()
+	var excluded_ids: Array = ProfileService.get_profile().get("correct_question_ids", []).duplicate()
+	QuestionBankService.load_next_random_question(excluded_ids)
 	_refresh_bank_state()
 
 
@@ -227,7 +221,7 @@ func _refresh_bank_state() -> void:
 	elif state == "retrying":
 		bank_status_label.text = "Question bank unavailable. Retrying in %d seconds." % QuestionBankService.next_retry_seconds
 	elif state == "ready":
-		bank_status_label.text = "%d questions ready" % QuestionBankService.get_all_questions().size()
+		bank_status_label.text = "Question bank ready"
 	elif state == "failed":
 		bank_status_label.text = "The question bank could not be loaded."
 	else: