Add exam-style question calculator

assets/icons/lucide/calculator.svg

@@ -0,0 +1,12 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+  <rect width="16" height="20" x="4" y="2" rx="2"/>
+  <line x1="8" x2="16" y1="6" y2="6"/>
+  <line x1="16" x2="16" y1="14" y2="18"/>
+  <path d="M16 10h.01"/>
+  <path d="M12 10h.01"/>
+  <path d="M8 10h.01"/>
+  <path d="M12 14h.01"/>
+  <path d="M8 14h.01"/>
+  <path d="M12 18h.01"/>
+  <path d="M8 18h.01"/>
+</svg>

assets/icons/lucide/calculator.svg.import

@@ -0,0 +1,43 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://dy8lr6snglfpm"
+path="res://.godot/imported/calculator.svg-0f64f216f45259cc59d80d23ea9a79a8.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://assets/icons/lucide/calculator.svg"
+dest_files=["res://.godot/imported/calculator.svg-0f64f216f45259cc59d80d23ea9a79a8.ctex"]
+
+[params]
+
+compress/mode=0
+compress/high_quality=false
+compress/lossy_quality=0.7
+compress/uastc_level=0
+compress/rdo_quality_loss=0.0
+compress/hdr_compression=1
+compress/normal_map=0
+compress/channel_pack=0
+mipmaps/generate=false
+mipmaps/limit=-1
+roughness/mode=0
+roughness/src_normal=""
+process/channel_remap/red=0
+process/channel_remap/green=1
+process/channel_remap/blue=2
+process/channel_remap/alpha=3
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/normal_map_invert_y=false
+process/hdr_as_srgb=false
+process/hdr_clamp_exposure=false
+process/size_limit=0
+detect_3d/compress_to=1
+svg/scale=1.0
+editor/scale_with_editor_scale=false
+editor/convert_colors_with_editor_theme=false

scripts/ui/calculator_panel.gd

@@ -0,0 +1,448 @@
+extends PanelContainer
+
+const Style := preload("res://scripts/ui/ui_style.gd")
+const Brand := preload("res://scripts/ui/medmind_style.gd")
+const MAX_ENTRY_LENGTH := 16
+
+var display_label: Label
+var operation_label: Label
+var keypad_buttons: Array[Button] = []
+var entry := "0"
+var accumulator := 0.0
+var pending_operator := ""
+var waiting_for_operand := true
+var last_operator := ""
+var last_operand := 0.0
+var has_last_operation := false
+var error_state := false
+var drag_active := false
+var drag_offset := Vector2.ZERO
+var has_been_positioned := false
+
+
+func _ready() -> void:
+	name = "CalculatorPanel"
+	visible = false
+	top_level = true
+	mouse_filter = Control.MOUSE_FILTER_STOP
+	custom_minimum_size = Vector2(310, 390)
+	size = custom_minimum_size
+	_build_ui()
+	if not get_viewport().size_changed.is_connected(_on_viewport_size_changed):
+		get_viewport().size_changed.connect(_on_viewport_size_changed)
+	_on_viewport_size_changed()
+	refresh_theme_controls()
+	_refresh_display()
+
+
+func open_panel() -> void:
+	visible = true
+	move_to_front()
+	if not has_been_positioned:
+		var viewport_size := get_viewport_rect().size
+		position = Vector2(maxf(12.0, viewport_size.x - size.x - 24.0), 72.0)
+		has_been_positioned = true
+	_clamp_to_viewport()
+
+
+func close_panel() -> void:
+	visible = false
+	drag_active = false
+
+
+func toggle_panel() -> void:
+	if visible:
+		close_panel()
+	else:
+		open_panel()
+
+
+func reset_calculation() -> void:
+	entry = "0"
+	accumulator = 0.0
+	pending_operator = ""
+	waiting_for_operand = true
+	last_operator = ""
+	last_operand = 0.0
+	has_last_operation = false
+	error_state = false
+	_refresh_display()
+
+
+func press_token(token: String) -> void:
+	if token.length() == 1 and token.is_valid_int():
+		_enter_digit(token)
+		return
+	match token:
+		".":
+			_enter_decimal()
+		"+", "−", "×", "÷":
+			_set_operator(token)
+		"=":
+			_equals()
+		"%":
+			_apply_unary("percent")
+		"√":
+			_apply_unary("sqrt")
+		"±":
+			_apply_unary("sign")
+		"⌫":
+			_backspace()
+		"AC":
+			reset_calculation()
+
+
+func get_display_text() -> String:
+	return entry
+
+
+func refresh_theme_controls() -> void:
+	if display_label == null:
+		return
+	var dark := UIThemeService.is_dark_mode()
+	add_theme_stylebox_override("panel", Brand.content_card_box(dark, true, Brand.ROYAL_BLUE))
+	display_label.add_theme_color_override("font_color", Brand.text_color(dark))
+	operation_label.add_theme_color_override("font_color", Brand.muted_color(dark))
+	for button in keypad_buttons:
+		var accent := Brand.ROYAL_BLUE if str(button.get_meta("calculator_token", "")) in ["+", "−", "×", "÷", "="] else Brand.SLATE
+		button.add_theme_stylebox_override("normal", Brand.badge_box(dark, accent))
+		button.add_theme_stylebox_override("hover", Brand.badge_box(dark, Brand.TEAL))
+		button.add_theme_stylebox_override("pressed", Brand.badge_box(dark, Brand.PURPLE))
+		button.add_theme_color_override("font_color", Brand.text_color(dark))
+
+
+func _build_ui() -> void:
+	var margin := MarginContainer.new()
+	margin.add_theme_constant_override("margin_left", 10)
+	margin.add_theme_constant_override("margin_right", 10)
+	margin.add_theme_constant_override("margin_top", 12)
+	margin.add_theme_constant_override("margin_bottom", 14)
+	add_child(margin)
+
+	var content := VBoxContainer.new()
+	content.add_theme_constant_override("separation", 10)
+	margin.add_child(content)
+
+	var title_bar := HBoxContainer.new()
+	title_bar.name = "CalculatorTitleBar"
+	title_bar.mouse_filter = Control.MOUSE_FILTER_STOP
+	title_bar.custom_minimum_size.y = 34
+	title_bar.gui_input.connect(_on_title_bar_gui_input)
+	content.add_child(title_bar)
+
+	var title := Label.new()
+	title.text = "Calculator"
+	title.size_flags_horizontal = Control.SIZE_EXPAND_FILL
+	title.mouse_filter = Control.MOUSE_FILTER_IGNORE
+	Brand.apply_font(title)
+	title.add_theme_font_size_override("font_size", 18)
+	title_bar.add_child(title)
+
+	var close := Button.new()
+	close.name = "CalculatorClose"
+	close.text = "×"
+	close.tooltip_text = "Close calculator"
+	close.custom_minimum_size = Vector2(36, 32)
+	close.focus_mode = Control.FOCUS_NONE
+	close.pressed.connect(close_panel)
+	title_bar.add_child(close)
+
+	var display_panel := PanelContainer.new()
+	display_panel.custom_minimum_size.y = 78
+	display_panel.add_theme_stylebox_override("panel", Style.panel_box(Color("101b31"), Style.CYAN))
+	content.add_child(display_panel)
+
+	var display_margin := MarginContainer.new()
+	display_margin.add_theme_constant_override("margin_left", 12)
+	display_margin.add_theme_constant_override("margin_right", 12)
+	display_margin.add_theme_constant_override("margin_top", 8)
+	display_margin.add_theme_constant_override("margin_bottom", 8)
+	display_panel.add_child(display_margin)
+
+	var display_stack := VBoxContainer.new()
+	display_margin.add_child(display_stack)
+	operation_label = Label.new()
+	operation_label.name = "CalculatorOperation"
+	operation_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_RIGHT
+	operation_label.add_theme_font_size_override("font_size", 13)
+	Brand.apply_font(operation_label)
+	display_stack.add_child(operation_label)
+	display_label = Label.new()
+	display_label.name = "CalculatorDisplay"
+	display_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_RIGHT
+	display_label.text_overrun_behavior = TextServer.OVERRUN_TRIM_ELLIPSIS
+	display_label.add_theme_font_size_override("font_size", 28)
+	Brand.apply_font(display_label)
+	display_stack.add_child(display_label)
+
+	var keypad := GridContainer.new()
+	keypad.name = "CalculatorKeypad"
+	keypad.columns = 4
+	keypad.add_theme_constant_override("h_separation", 6)
+	keypad.add_theme_constant_override("v_separation", 8)
+	content.add_child(keypad)
+
+	var tokens := [
+		"AC", "⌫", "±", "√",
+		"7", "8", "9", "÷",
+		"4", "5", "6", "×",
+		"1", "2", "3", "−",
+		"%", "0", ".", "+",
+		"", "", "", "="
+	]
+	for token in tokens:
+		var button := Button.new()
+		button.custom_minimum_size = Vector2(44, 45)
+		button.size_flags_horizontal = Control.SIZE_EXPAND_FILL
+		button.focus_mode = Control.FOCUS_NONE
+		if token == "":
+			button.visible = false
+			keypad.add_child(button)
+			continue
+		button.text = token
+		button.set_meta("calculator_token", token)
+		button.tooltip_text = _token_tooltip(token)
+		button.add_theme_font_size_override("font_size", 18)
+		Brand.apply_font(button)
+		UISoundService.set_button_sound(button, "toggle")
+		button.pressed.connect(press_token.bind(token))
+		keypad.add_child(button)
+		keypad_buttons.append(button)
+
+
+func _input(event: InputEvent) -> void:
+	if not visible or not (event is InputEventKey):
+		return
+	var key_event := event as InputEventKey
+	if not key_event.pressed or key_event.echo:
+		return
+	var token := ""
+	if key_event.keycode == KEY_ESCAPE:
+		close_panel()
+		get_viewport().set_input_as_handled()
+		return
+	if key_event.keycode in [KEY_ENTER, KEY_KP_ENTER]:
+		token = "="
+	elif key_event.keycode == KEY_BACKSPACE:
+		token = "⌫"
+	elif key_event.keycode == KEY_DELETE:
+		token = "AC"
+	elif key_event.unicode > 0:
+		var character := String.chr(key_event.unicode)
+		match character:
+			"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", ".", "%", "=":
+				token = character
+			"+": token = "+"
+			"-": token = "−"
+			"*", "x", "X": token = "×"
+			"/": token = "÷"
+			"c", "C": token = "AC"
+	if token == "":
+		return
+	press_token(token)
+	get_viewport().set_input_as_handled()
+
+
+func _enter_digit(digit: String) -> void:
+	if error_state:
+		reset_calculation()
+	if waiting_for_operand:
+		entry = digit
+		waiting_for_operand = false
+	elif entry == "0":
+		entry = digit
+	elif entry.length() < MAX_ENTRY_LENGTH:
+		entry += digit
+	_refresh_display()
+
+
+func _enter_decimal() -> void:
+	if error_state:
+		reset_calculation()
+	if waiting_for_operand:
+		entry = "0."
+		waiting_for_operand = false
+	elif not "." in entry and entry.length() < MAX_ENTRY_LENGTH:
+		entry += "."
+	_refresh_display()
+
+
+func _set_operator(operator: String) -> void:
+	if error_state:
+		return
+	var current := _entry_value()
+	if pending_operator != "" and not waiting_for_operand:
+		if not _perform_operation(pending_operator, current):
+			return
+	else:
+		accumulator = current
+	pending_operator = operator
+	waiting_for_operand = true
+	has_last_operation = false
+	_refresh_display()
+
+
+func _equals() -> void:
+	if error_state:
+		return
+	if pending_operator != "":
+		var operand := accumulator if waiting_for_operand else _entry_value()
+		var operator := pending_operator
+		if not _perform_operation(operator, operand):
+			return
+		last_operator = operator
+		last_operand = operand
+		has_last_operation = true
+		pending_operator = ""
+	elif has_last_operation:
+		if not _perform_operation(last_operator, last_operand):
+			return
+	else:
+		return
+	waiting_for_operand = true
+	_refresh_display()
+
+
+func _apply_unary(operation: String) -> void:
+	if error_state:
+		return
+	var value := _entry_value()
+	match operation:
+		"percent":
+			value /= 100.0
+		"sqrt":
+			if value < 0.0:
+				_set_error()
+				return
+			value = sqrt(value)
+		"sign":
+			value = -value
+	entry = _format_number(value)
+	if pending_operator == "":
+		accumulator = value
+	waiting_for_operand = false
+	_refresh_display()
+
+
+func _backspace() -> void:
+	if error_state:
+		reset_calculation()
+		return
+	if waiting_for_operand:
+		return
+	entry = entry.left(entry.length() - 1)
+	if entry in ["", "-"]:
+		entry = "0"
+		waiting_for_operand = true
+	_refresh_display()
+
+
+func _perform_operation(operator: String, operand: float) -> bool:
+	var result := accumulator
+	match operator:
+		"+": result += operand
+		"−": result -= operand
+		"×": result *= operand
+		"÷":
+			if is_zero_approx(operand):
+				_set_error()
+				return false
+			result /= operand
+	if is_nan(result) or is_inf(result):
+		_set_error()
+		return false
+	accumulator = result
+	entry = _format_number(result)
+	return true
+
+
+func _entry_value() -> float:
+	return entry.to_float()
+
+
+func _format_number(value: float) -> String:
+	if is_zero_approx(value):
+		return "0"
+	var formatted := String.num(value, 12)
+	if "." in formatted:
+		while formatted.ends_with("0"):
+			formatted = formatted.left(formatted.length() - 1)
+		if formatted.ends_with("."):
+			formatted = formatted.left(formatted.length() - 1)
+	if formatted.length() > MAX_ENTRY_LENGTH:
+		formatted = String.num_scientific(value).replace("e+", "e")
+	return formatted
+
+
+func _set_error() -> void:
+	entry = "Error"
+	error_state = true
+	pending_operator = ""
+	waiting_for_operand = true
+	has_last_operation = false
+	_refresh_display()
+
+
+func _refresh_display() -> void:
+	if display_label == null:
+		return
+	display_label.text = entry
+	operation_label.text = ("%s %s" % [_format_number(accumulator), pending_operator]) if pending_operator != "" else ""
+
+
+func _on_title_bar_gui_input(event: InputEvent) -> void:
+	var touch_event := event as InputEventScreenTouch
+	if touch_event != null:
+		drag_active = touch_event.pressed
+		if drag_active:
+			drag_offset = touch_event.position
+		get_viewport().set_input_as_handled()
+		return
+	var touch_drag := event as InputEventScreenDrag
+	if touch_drag != null and drag_active:
+		global_position += touch_drag.relative
+		_clamp_to_viewport()
+		get_viewport().set_input_as_handled()
+		return
+	var mouse_event := event as InputEventMouseButton
+	if mouse_event != null and mouse_event.button_index == MOUSE_BUTTON_LEFT:
+		drag_active = mouse_event.pressed
+		if drag_active:
+			drag_offset = mouse_event.global_position - global_position
+		get_viewport().set_input_as_handled()
+		return
+	var motion := event as InputEventMouseMotion
+	if motion != null and drag_active:
+		global_position = motion.global_position - drag_offset
+		_clamp_to_viewport()
+		get_viewport().set_input_as_handled()
+
+
+func _on_viewport_size_changed() -> void:
+	var viewport_size := get_viewport_rect().size
+	custom_minimum_size.x = minf(310.0, maxf(216.0, viewport_size.x - 24.0))
+	size.x = custom_minimum_size.x
+	_clamp_to_viewport()
+
+
+func _clamp_to_viewport() -> void:
+	if not is_inside_tree():
+		return
+	var viewport_size := get_viewport_rect().size
+	position.x = clampf(position.x, 12.0, maxf(12.0, viewport_size.x - size.x - 12.0))
+	position.y = clampf(position.y, 12.0, maxf(12.0, viewport_size.y - size.y - 12.0))
+
+
+func _token_tooltip(token: String) -> String:
+	return {
+		"AC": "Clear calculation",
+		"⌫": "Backspace",
+		"±": "Change sign",
+		"√": "Square root",
+		"%": "Convert to percent",
+		"÷": "Divide",
+		"×": "Multiply",
+		"−": "Subtract",
+		"+": "Add",
+		"=": "Equals"
+	}.get(token, token)

scripts/ui/calculator_panel.gd.uid

@@ -0,0 +1 @@
+uid://dssyep5a2sime

scripts/ui/question_player.gd

@@ -3,6 +3,7 @@ extends VBoxContainer
 const Style := preload("res://scripts/ui/ui_style.gd")
 const Brand := preload("res://scripts/ui/medmind_style.gd")
 const FlashcardPrefillDialog := preload("res://scripts/ui/flashcard_prefill_dialog.gd")
+const CalculatorPanel := preload("res://scripts/ui/calculator_panel.gd")
 const CLEAR_HIGHLIGHT_DARK_ICON := preload("res://assets/icons/medmind/clear-highlight-dark.svg")
 const CLEAR_HIGHLIGHT_LIGHT_ICON := preload("res://assets/icons/medmind/clear-highlight-light.svg")
 const LABS_DARK_ICON := preload("res://assets/icons/medmind/labs-dark.svg")
@@ -81,6 +82,7 @@ var skip_button: Button
 var text_smaller_button: Button
 var text_larger_button: Button
 var labs_button: Button
+var calculator_button: Button
 var clear_highlight_button: Button
 var flag_button: Button
 var report_button: Button
@@ -109,6 +111,7 @@ var feedback_fog: ColorRect
 var labs_overlay: Control
 var labs_panel: PanelContainer
 var labs_content: VBoxContainer
+var calculator_panel
 var report_overlay: Control
 var report_panel: PanelContainer
 var report_form_content: VBoxContainer
@@ -258,6 +261,19 @@ func _ready() -> void:
 	text_larger_button.pressed.connect(func(): _adjust_question_text_scale(TEXT_SCALE_STEP))
 	question_toolbar.add_child(text_larger_button)
 
+	calculator_button = Button.new()
+	calculator_button.name = "CalculatorButton"
+	calculator_button.tooltip_text = "Open calculator"
+	calculator_button.icon = preload("res://assets/icons/lucide/calculator.svg")
+	calculator_button.custom_minimum_size = Vector2(44, 44)
+	calculator_button.add_theme_constant_override("icon_max_width", 22)
+	calculator_button.alignment = HORIZONTAL_ALIGNMENT_CENTER
+	calculator_button.icon_alignment = HORIZONTAL_ALIGNMENT_CENTER
+	calculator_button.focus_mode = Control.FOCUS_NONE
+	UISoundService.set_button_sound(calculator_button, "open")
+	calculator_button.pressed.connect(_toggle_calculator)
+	question_toolbar.add_child(calculator_button)
+
 	labs_button = Button.new()
 	labs_button.tooltip_text = "Review lab results"
 	labs_button.custom_minimum_size = Vector2(44, 44)
@@ -574,6 +590,8 @@ func _ready() -> void:
 	add_child(feedback_fog)
 
 	_build_labs_modal()
+	calculator_panel = CalculatorPanel.new()
+	add_child(calculator_panel)
 	_build_report_modal()
 	_build_media_viewer()
 	resized.connect(_fit_modal_panels)
@@ -909,7 +927,7 @@ func _apply_question_theme() -> void:
 	var navigator_heading := navigator_popup.find_child("NavigatorHeading", true, false) as Label
 	if navigator_heading != null:
 		navigator_heading.add_theme_color_override("font_color", Brand.text_color(dark))
-	for control in [text_smaller_button, text_larger_button, bookmark_button, notes_button, flashcard_button, app_feedback_button]:
+	for control in [text_smaller_button, text_larger_button, calculator_button, bookmark_button, notes_button, flashcard_button, app_feedback_button]:
 		if control == null:
 			continue
 		var active: bool = control == bookmark_button and BookmarkService.is_bookmarked(str(BlockSessionService.get_current_question().get("id", "")))
@@ -923,6 +941,8 @@ func _apply_question_theme() -> void:
 	_style_asset_toolbar_button(report_button, REPORT_QUESTION_DARK_ICON if dark else REPORT_QUESTION_LIGHT_ICON, dark)
 	_style_asset_toolbar_button(flag_button, FLAG_DARK_ICON if dark else FLAG_LIGHT_ICON, dark, flagged)
 	_style_theme_toggle_button(dark)
+	if calculator_panel != null:
+		calculator_panel.refresh_theme_controls()
 	if skip_button != null:
 		skip_button.add_theme_stylebox_override("normal", _toolbar_box(dark))
 		skip_button.add_theme_stylebox_override("hover", _toolbar_box(dark, true))
@@ -963,6 +983,9 @@ func on_hide() -> void:
 	_hide_media_viewer()
 	_hide_report_modal(true)
 	_hide_labs_modal()
+	if calculator_panel != null:
+		calculator_panel.close_panel()
+		calculator_panel.reset_calculation()
 
 
 func _save_simulation_current_response() -> void:
@@ -1049,6 +1072,8 @@ func _input(event: InputEvent) -> void:
 		_hide_labs_modal()
 		get_viewport().set_input_as_handled()
 		return
+	if calculator_panel != null and calculator_panel.visible and event is InputEventKey:
+		return
 	if not visible or pending_correct_advance or stem_label == null:
 		return
 
@@ -2038,9 +2063,16 @@ func _refresh_toolbar_state() -> void:
 		var bookmark_value := BookmarkService.is_bookmarked(bookmark_question_id)
 		var bookmark_pending := BookmarkService.is_pending(bookmark_question_id)
 		bookmark_button.tooltip_text = ("Saved; waiting to sync" if bookmark_pending else "Remove bookmark") if bookmark_value else ("Removal waiting to sync" if bookmark_pending else "Save question")
+	if calculator_button != null:
+		calculator_button.visible = true
 	_apply_question_theme()
 
 
+func _toggle_calculator() -> void:
+	if calculator_panel != null:
+		calculator_panel.toggle_panel()
+
+
 func _toggle_bookmark_current_question() -> void:
 	var question := BlockSessionService.get_current_question()
 	if not question.is_empty():

tests/calculator_panel_test.gd

@@ -0,0 +1,126 @@
+extends SceneTree
+
+var failures := 0
+
+
+func _initialize() -> void:
+	call_deferred("_run")
+
+
+func _run() -> void:
+	_test_basic_arithmetic()
+	_test_decimal_and_chained_operations()
+	_test_percent_and_sign()
+	_test_square_root()
+	_test_repeated_equals()
+	_test_backspace_and_clear()
+	_test_error_recovery()
+	await _test_runtime_panel_behavior()
+	quit(1 if failures > 0 else 0)
+
+
+func _calculator():
+	return load("res://scripts/ui/calculator_panel.gd").new()
+
+
+func _press(calculator, tokens: Array) -> void:
+	for token in tokens:
+		calculator.press_token(str(token))
+
+
+func _test_basic_arithmetic() -> void:
+	var calculator = _calculator()
+	_press(calculator, ["9", "+", "6", "="])
+	_assert(calculator.get_display_text() == "15", "calculator should add operands")
+	calculator.reset_calculation()
+	_press(calculator, ["9", "−", "4", "="])
+	_assert(calculator.get_display_text() == "5", "calculator should subtract operands")
+	calculator.reset_calculation()
+	_press(calculator, ["7", "×", "8", "="])
+	_assert(calculator.get_display_text() == "56", "calculator should multiply operands")
+	calculator.reset_calculation()
+	_press(calculator, ["8", "÷", "4", "="])
+	_assert(calculator.get_display_text() == "2", "calculator should divide operands")
+	calculator.free()
+
+
+func _test_decimal_and_chained_operations() -> void:
+	var calculator = _calculator()
+	_press(calculator, ["1", ".", "5", "+", "2", ".", "5", "×", "2", "="])
+	_assert(calculator.get_display_text() == "8", "calculator should evaluate chained handheld operations left to right")
+	calculator.free()
+
+
+func _test_percent_and_sign() -> void:
+	var calculator = _calculator()
+	_press(calculator, ["5", "%"])
+	_assert(calculator.get_display_text() == "0.05", "percent should convert the displayed operand to a fraction")
+	_press(calculator, ["±"])
+	_assert(calculator.get_display_text() == "-0.05", "sign toggle should negate the displayed operand")
+	calculator.free()
+
+
+func _test_square_root() -> void:
+	var calculator = _calculator()
+	_press(calculator, ["8", "1", "√"])
+	_assert(calculator.get_display_text() == "9", "square root should replace the displayed operand")
+	calculator.free()
+
+
+func _test_repeated_equals() -> void:
+	var calculator = _calculator()
+	_press(calculator, ["5", "+", "2", "=", "="])
+	_assert(calculator.get_display_text() == "9", "repeated equals should replay the last binary operation")
+	calculator.free()
+
+
+func _test_backspace_and_clear() -> void:
+	var calculator = _calculator()
+	_press(calculator, ["1", "2", "3", "⌫"])
+	_assert(calculator.get_display_text() == "12", "backspace should remove the final entry digit")
+	_press(calculator, ["AC"])
+	_assert(calculator.get_display_text() == "0", "clear should reset the display")
+	calculator.free()
+
+
+func _test_error_recovery() -> void:
+	var calculator = _calculator()
+	_press(calculator, ["8", "÷", "0", "="])
+	_assert(calculator.get_display_text() == "Error", "division by zero should display an error")
+	_press(calculator, ["4"])
+	_assert(calculator.get_display_text() == "4", "digit entry should recover from an error")
+	_press(calculator, ["±", "√"])
+	_assert(calculator.get_display_text() == "Error", "square root of a negative operand should display an error")
+	calculator.free()
+
+
+func _test_runtime_panel_behavior() -> void:
+	var host := Control.new()
+	host.size = Vector2(360, 640)
+	root.add_child(host)
+	var calculator = _calculator()
+	host.add_child(calculator)
+	await process_frame
+	calculator.open_panel()
+	await process_frame
+	_assert(calculator.visible, "calculator should open as a floating panel")
+	_assert(calculator.size.x <= 336.0, "calculator should fit a narrow web viewport")
+	_press(calculator, ["2", "+", "3", "="])
+	calculator.close_panel()
+	calculator.open_panel()
+	_assert(calculator.get_display_text() == "5", "closing and reopening should preserve the active-session value")
+	calculator.position = Vector2(1000, 1000)
+	calculator._clamp_to_viewport()
+	_assert(calculator.position.x + calculator.size.x <= calculator.get_viewport_rect().size.x, "calculator dragging should remain horizontally bounded")
+	_assert(calculator.position.y + calculator.size.y <= calculator.get_viewport_rect().size.y, "calculator dragging should remain vertically bounded")
+	calculator.reset_calculation()
+	_assert(calculator.get_display_text() == "0", "session reset should clear calculator state")
+	host.queue_free()
+	await process_frame
+
+
+func _assert(condition: bool, message: String) -> void:
+	if condition:
+		return
+	failures += 1
+	push_error(message)

tests/calculator_panel_test.gd.uid

@@ -0,0 +1 @@
+uid://j08gujwjb7jx

tests/post_answer_review_test.gd

@@ -361,6 +361,8 @@ func _test_player_runtime_construction() -> void:
 	_assert(player.clear_highlight_button.icon != null, "clear highlights should use the supplied toolbar artwork")
 	_assert(player.report_button.icon != null, "report question should use the supplied toolbar artwork")
 	_assert(player.labs_button.icon != null, "lab results should use the supplied toolbar artwork")
+	_assert(player.calculator_button != null and player.calculator_button.icon != null, "every question mode should expose the calculator tool")
+	_assert(player.calculator_panel != null, "question player should construct the floating calculator once")
 	_assert(player.notes_button != null and player.notes_button.icon != null, "practice questions should expose the notes tool")
 	for icon_button in [player.clear_highlight_button, player.report_button, player.labs_button]:
 		_assert(icon_button.alignment == HORIZONTAL_ALIGNMENT_CENTER and icon_button.icon_alignment == HORIZONTAL_ALIGNMENT_CENTER, "question toolbar artwork should be horizontally centered")
@@ -377,12 +379,16 @@ func _test_player_runtime_construction() -> void:
 	_assert(player.choice_badges.size() == 5, "question player should construct an answer badge for every visible choice slot")
 	_assert(player.choice_followup_panels[2].get_parent() == player.choice_rows[2], "distractor remediation should remain nested inside its answer choice")
 	var prior_session_kind: String = root.get_node("BlockSessionService").session_kind
-	root.get_node("BlockSessionService").session_kind = "simulation"
+	for session_kind in ["block", "core", "bookmark", "review", "simulation"]:
-	player._refresh_toolbar_state()
+		root.get_node("BlockSessionService").session_kind = session_kind
-	_assert(not player.notes_button.visible, "timed simulations should hide the notes tool")
+		player._refresh_toolbar_state()
+		_assert(player.calculator_button.visible, "%s question sessions should expose the calculator tool" % session_kind)
 	root.get_node("BlockSessionService").session_kind = "core"
 	player._refresh_toolbar_state()
 	_assert(player.notes_button.visible, "practice question runs should show the notes tool")
+	root.get_node("BlockSessionService").session_kind = "simulation"
+	player._refresh_toolbar_state()
+	_assert(not player.notes_button.visible, "timed simulations should hide the notes tool")
 	root.get_node("BlockSessionService").session_kind = prior_session_kind
 	player.choice_followup_panels[2].visible = true
 	player.locked_wrong_choice_ids = ["C"]