extends VBoxContainer

const Brand := preload("res://scripts/ui/medmind_style.gd")
const EXPLANATION_ICON := preload("res://assets/icons/lucide/book-open.svg")
const LAB_ICON := preload("res://assets/icons/lucide/microscope.svg")
const REFERENCE_ICON := preload("res://assets/icons/lucide/link.svg")
const BLOCK_SIZES := [20, 19, 19, 20, 19, 19, 20, 19, 19, 20, 19, 19]
const FILTER_DEFS := [["All", "all", 0], ["Incorrect", "incorrect", 1], ["Unanswered", "unanswered", 2], ["Flagged", "flagged", 3]]

var main: Control
var simulation := {}
var questions: Array = []
var responses := {}
var filtered_indices: Array[int] = []
var review_position := 0
var active_filter := "all"
var back_button: Button
var progress_label: Label
var filter_buttons: Dictionary = {}
var content: VBoxContainer
var previous_button: Button
var next_button: Button
var empty_label: Label
var media_requests: Array[HTTPRequest] = []
var image_overlay: Control
var image_texture: TextureRect
var image_close_button: Button
var return_screen := "selection"


func _ready() -> void:
	set_anchors_preset(Control.PRESET_FULL_RECT)
	add_theme_constant_override("separation", 12)

	var toolbar := HBoxContainer.new()
	toolbar.add_theme_constant_override("separation", 12)
	add_child(toolbar)
	back_button = Button.new()
	back_button.text = "< Results"
	back_button.custom_minimum_size = Vector2(0, 40)
	back_button.pressed.connect(func(): main.show_screen("simulation_results", {"simulation": simulation, "return_screen": return_screen}))
	toolbar.add_child(back_button)
	progress_label = Label.new()
	progress_label.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	progress_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
	progress_label.add_theme_font_override("font", Brand.font)
	progress_label.add_theme_font_size_override("font_size", 15)
	toolbar.add_child(progress_label)
	var toolbar_spacer := Control.new()
	toolbar_spacer.custom_minimum_size.x = back_button.custom_minimum_size.x
	toolbar.add_child(toolbar_spacer)

	var filters := GridContainer.new()
	filters.columns = 4
	filters.add_theme_constant_override("h_separation", 8)
	filters.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	add_child(filters)
	var group := ButtonGroup.new()
	for definition in FILTER_DEFS:
		var button := Button.new()
		button.text = definition[0]
		button.toggle_mode = true
		button.button_group = group
		button.button_pressed = definition[1] == "all"
		button.custom_minimum_size = Vector2(0, 38)
		button.pressed.connect(_set_filter.bind(definition[1]))
		button.size_flags_horizontal = Control.SIZE_EXPAND_FILL
		filters.add_child(button)
		filter_buttons[definition[1]] = button

	var scroll := ScrollContainer.new()
	scroll.size_flags_vertical = Control.SIZE_EXPAND_FILL
	scroll.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	add_child(scroll)
	content = VBoxContainer.new()
	content.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	content.add_theme_constant_override("separation", 14)
	scroll.add_child(content)
	empty_label = Label.new()
	empty_label.visible = false
	empty_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
	empty_label.add_theme_font_override("font", Brand.font)
	empty_label.add_theme_font_size_override("font_size", 16)
	content.add_child(empty_label)

	var navigation := HBoxContainer.new()
	navigation.add_theme_constant_override("separation", 10)
	add_child(navigation)
	previous_button = Button.new()
	previous_button.text = "< Previous"
	previous_button.custom_minimum_size = Vector2(160, 48)
	previous_button.pressed.connect(_move.bind(-1))
	navigation.add_child(previous_button)
	var spacer := Control.new()
	spacer.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	navigation.add_child(spacer)
	next_button = Button.new()
	next_button.text = "Next >"
	next_button.custom_minimum_size = Vector2(160, 48)
	next_button.pressed.connect(_move.bind(1))
	navigation.add_child(next_button)
	_build_image_overlay()

	UIThemeService.theme_changed.connect(func(_dark: bool): refresh_theme_controls())
	refresh_theme_controls()


func refresh_theme_controls() -> void:
	var dark := UIThemeService.is_dark_mode()
	_style_outline_button(back_button, Brand.ROYAL_BLUE, dark)
	progress_label.add_theme_color_override("font_color", Brand.text_color(dark))
	for filter_name in filter_buttons:
		var accent := _filter_accent(filter_name)
		_style_filter_chip(filter_buttons[filter_name], accent, dark)
	_style_outline_button(previous_button, Brand.SLATE, dark)
	_style_gradient_button(next_button)
	if is_instance_valid(image_close_button):
		_style_outline_button(image_close_button, Brand.SLATE, dark)
	_render_question()


func on_show(payload: Variant = null) -> void:
	if typeof(payload) == TYPE_DICTIONARY:
		var wrapper: Dictionary = payload
		simulation = wrapper.get("simulation", wrapper)
		return_screen = str(wrapper.get("return_screen", "selection"))
	questions = simulation.get("reviewQuestions", [])
	responses.clear()
	for response in simulation.get("responses", []):
		responses[str(response.get("questionExternalId", ""))] = response
	active_filter = "all"
	filter_buttons["all"].button_pressed = true
	review_position = 0
	_apply_filter()


func on_hide() -> void:
	_clear_media_requests()
	image_overlay.visible = false


func _unhandled_key_input(event: InputEvent) -> void:
	if not visible or not event.pressed or event.echo:
		return
	if event.keycode == KEY_LEFT:
		_move(-1)
		get_viewport().set_input_as_handled()
	elif event.keycode == KEY_RIGHT:
		_move(1)
		get_viewport().set_input_as_handled()
	elif event.keycode == KEY_ESCAPE and image_overlay.visible:
		image_overlay.visible = false
		get_viewport().set_input_as_handled()


func _set_filter(filter_name: String) -> void:
	active_filter = filter_name
	review_position = 0
	_apply_filter()


func _apply_filter() -> void:
	filtered_indices.clear()
	for index in range(questions.size()):
		var question: Dictionary = questions[index]
		var response: Dictionary = responses.get(str(question.get("externalId", "")), {})
		var selected := str(response.get("choiceId", ""))
		var correct := str(question.get("correctChoiceId", ""))
		if _matches_filter(active_filter, selected, correct, bool(response.get("flagged", false))):
			filtered_indices.append(index)
	_render_question()


func _move(direction: int) -> void:
	var target := review_position + direction
	if target < 0 or target >= filtered_indices.size():
		return
	review_position = target
	_render_question()


func _render_question() -> void:
	_clear_content()
	_clear_media_requests()
	var dark := UIThemeService.is_dark_mode()
	if filtered_indices.is_empty():
		empty_label = Label.new()
		empty_label.text = "No questions match this filter."
		empty_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
		empty_label.add_theme_font_override("font", Brand.font)
		empty_label.add_theme_font_size_override("font_size", 16)
		empty_label.add_theme_color_override("font_color", Brand.muted_color(dark))
		content.add_child(empty_label)
		progress_label.text = "0 questions"
		previous_button.disabled = true
		next_button.disabled = true
		return
	var question_index := filtered_indices[review_position]
	var question: Dictionary = questions[question_index]
	var response: Dictionary = responses.get(str(question.get("externalId", "")), {})
	var selected := str(response.get("choiceId", ""))
	var correct := str(question.get("correctChoiceId", ""))
	var outcome := "Correct" if selected == correct else "Unanswered" if selected == "" else "Incorrect"
	progress_label.text = "Question %d of %d  |  Block %d  |  %s" % [review_position + 1, filtered_indices.size(), _block_for_index(question_index) + 1, outcome]
	previous_button.disabled = review_position == 0
	next_button.disabled = review_position + 1 >= filtered_indices.size()

	var stem_card := _card(dark)
	var stem_column := VBoxContainer.new()
	stem_column.add_theme_constant_override("separation", 10)
	stem_card.get_child(0).add_child(stem_column)
	_add_text(stem_column, str(question.get("stem", "")), 15, Brand.text_color(dark), dark)
	_add_media(stem_column, question.get("media", []))
	_add_labs(stem_column, question.get("labs", []), dark)
	content.add_child(stem_card)
	_add_text(content, str(question.get("leadIn", "")), 17, Brand.text_color(dark), dark, true)

	var explanations: Dictionary = question.get("choiceExplanations", {})
	for raw_choice in question.get("choices", []):
		var choice: Dictionary = raw_choice
		var choice_id := str(choice.get("id", ""))
		var is_correct := choice_id == correct
		var is_selected := choice_id == selected
		content.add_child(_build_choice_row(dark, choice_id, str(choice.get("text", "")), str(explanations.get(choice_id, "")), is_correct, is_selected))

	_add_heading(content, "Explanation", EXPLANATION_ICON, dark)
	_add_text(content, str(question.get("explanation", "")), 14, Brand.text_color(dark), dark)
	_add_references(content, question.get("references", []), dark)


func _build_choice_row(dark: bool, choice_id: String, choice_text: String, explanation: String, is_correct: bool, is_selected: bool) -> PanelContainer:
	var accent := Brand.SUCCESS if is_correct else (Brand.MAGENTA if is_selected else Brand.SLATE)
	var tinted := is_correct or is_selected
	var panel := PanelContainer.new()
	panel.add_theme_stylebox_override("panel", _choice_box(dark, accent, tinted))
	var margin := MarginContainer.new()
	margin.add_theme_constant_override("margin_left", 16)
	margin.add_theme_constant_override("margin_right", 16)
	margin.add_theme_constant_override("margin_top", 12)
	margin.add_theme_constant_override("margin_bottom", 12)
	panel.add_child(margin)
	var column := VBoxContainer.new()
	column.add_theme_constant_override("separation", 6)
	margin.add_child(column)

	var row := HBoxContainer.new()
	row.add_theme_constant_override("separation", 10)
	column.add_child(row)
	var answer := Label.new()
	answer.text = "%s. %s" % [choice_id, choice_text]
	answer.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
	answer.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	answer.add_theme_font_override("font", Brand.font)
	answer.add_theme_font_size_override("font_size", 14)
	answer.add_theme_color_override("font_color", Brand.text_color(dark))
	row.add_child(answer)
	if is_correct or is_selected:
		var badge := Label.new()
		badge.text = "Correct answer" if is_correct else "Your answer"
		badge.add_theme_font_override("font", Brand.font)
		badge.add_theme_font_size_override("font_size", 11)
		badge.add_theme_color_override("font_color", accent)
		badge.add_theme_stylebox_override("normal", Brand.badge_box(dark, accent))
		badge.size_flags_vertical = Control.SIZE_SHRINK_CENTER
		row.add_child(badge)

	if not explanation.is_empty():
		var detail := Label.new()
		detail.text = explanation
		detail.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
		detail.add_theme_font_override("font", Brand.font)
		detail.add_theme_font_size_override("font_size", 12)
		detail.add_theme_color_override("font_color", Brand.muted_color(dark))
		column.add_child(detail)

	return panel


func _choice_box(dark: bool, accent: Color, tinted: bool) -> StyleBoxFlat:
	var box := StyleBoxFlat.new()
	if tinted:
		box.bg_color = Color(accent, 0.16 if dark else 0.10)
		box.border_color = accent
	else:
		box.bg_color = Color("11182e") if dark else Brand.LIGHT_SURFACE
		box.border_color = Color("2a365a") if dark else Brand.LIGHT_BORDER
	box.set_border_width_all(1)
	box.set_corner_radius_all(12)
	return box


func _card(dark: bool) -> PanelContainer:
	var panel := PanelContainer.new()
	panel.add_theme_stylebox_override("panel", Brand.content_card_box(dark, false))
	var margin := MarginContainer.new()
	margin.add_theme_constant_override("margin_left", 16)
	margin.add_theme_constant_override("margin_right", 16)
	margin.add_theme_constant_override("margin_top", 14)
	margin.add_theme_constant_override("margin_bottom", 14)
	panel.add_child(margin)
	return panel


func _add_heading(parent: Control, value: String, icon: Texture2D, dark: bool) -> void:
	var row := HBoxContainer.new()
	row.add_theme_constant_override("separation", 8)
	var icon_rect := TextureRect.new()
	icon_rect.texture = icon
	icon_rect.custom_minimum_size = Vector2(18, 18)
	icon_rect.expand_mode = TextureRect.EXPAND_IGNORE_SIZE
	icon_rect.stretch_mode = TextureRect.STRETCH_KEEP_ASPECT_CENTERED
	icon_rect.modulate = Brand.ROYAL_BLUE
	row.add_child(icon_rect)
	var label := Label.new()
	label.text = value
	label.add_theme_font_override("font", Brand.font)
	label.add_theme_font_size_override("font_size", 16)
	label.add_theme_color_override("font_color", Brand.text_color(dark))
	row.add_child(label)
	parent.add_child(row)


func _add_text(parent: Control, value: String, size_value: int, color: Color, _dark: bool, bold_ish: bool = false) -> void:
	if value.is_empty():
		return
	var label := Label.new()
	label.text = value
	label.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
	label.add_theme_font_override("font", Brand.font)
	label.add_theme_font_size_override("font_size", size_value + 2 if bold_ish else size_value)
	label.add_theme_color_override("font_color", color)
	parent.add_child(label)


func _add_labs(parent: Control, labs: Array, dark: bool) -> void:
	if labs.is_empty():
		return
	_add_heading(parent, "Laboratory studies", LAB_ICON, dark)
	for raw_lab in labs:
		var lab: Dictionary = raw_lab
		_add_text(parent, "%s: %s" % [str(lab.get("name", lab.get("test", ""))), str(lab.get("value", ""))], 13, Brand.muted_color(dark), dark)


func _add_references(parent: Control, references: Array, dark: bool) -> void:
	if references.is_empty():
		return
	_add_heading(parent, "References", REFERENCE_ICON, dark)
	for raw_reference in references:
		var reference: Dictionary = raw_reference
		var url := str(reference.get("url", ""))
		if not url.begins_with("https://"):
			continue
		var link := LinkButton.new()
		link.text = str(reference.get("title", url))
		link.tooltip_text = url
		link.size_flags_horizontal = Control.SIZE_SHRINK_BEGIN
		link.text_overrun_behavior = TextServer.OVERRUN_TRIM_ELLIPSIS
		link.add_theme_color_override("font_color", Brand.SKY_BLUE)
		link.pressed.connect(func(target_url: String = url): OS.shell_open(target_url))
		parent.add_child(link)


func _add_media(parent: Control, media: Array) -> void:
	for raw_url in media:
		var url := _resolve_media_url(str(raw_url))
		if url.is_empty():
			continue
		var preview := TextureRect.new()
		preview.custom_minimum_size = Vector2(0, 260)
		preview.expand_mode = TextureRect.EXPAND_IGNORE_SIZE
		preview.stretch_mode = TextureRect.STRETCH_KEEP_ASPECT_CENTERED
		preview.mouse_default_cursor_shape = Control.CURSOR_POINTING_HAND
		parent.add_child(preview)
		var request := HTTPRequest.new()
		request.request_completed.connect(func(result: int, code: int, _headers: PackedStringArray, body: PackedByteArray): _on_media_loaded(result, code, body, preview))
		media_requests.append(request)
		add_child(request)
		request.request(url)


func _on_media_loaded(result: int, code: int, body: PackedByteArray, preview: TextureRect) -> void:
	if result != HTTPRequest.RESULT_SUCCESS or code < 200 or code >= 300 or not is_instance_valid(preview):
		return
	var image := Image.new()
	var error := image.load_png_from_buffer(body)
	if error != OK: error = image.load_jpg_from_buffer(body)
	if error != OK: error = image.load_webp_from_buffer(body)
	if error != OK: return
	preview.texture = ImageTexture.create_from_image(image)
	preview.gui_input.connect(func(event: InputEvent):
		if event is InputEventMouseButton and event.button_index == MOUSE_BUTTON_LEFT and event.pressed:
			image_texture.texture = preview.texture
			image_overlay.visible = true
	)


func _build_image_overlay() -> void:
	image_overlay = Control.new()
	image_overlay.visible = false
	image_overlay.top_level = true
	image_overlay.mouse_filter = Control.MOUSE_FILTER_STOP
	image_overlay.set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)
	add_child(image_overlay)
	var background := ColorRect.new()
	background.color = Color(Brand.background_color(UIThemeService.is_dark_mode()), 0.97)
	background.set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)
	image_overlay.add_child(background)
	image_texture = TextureRect.new()
	image_texture.set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)
	image_texture.offset_left = 24
	image_texture.offset_top = 72
	image_texture.offset_right = -24
	image_texture.offset_bottom = -24
	image_texture.expand_mode = TextureRect.EXPAND_IGNORE_SIZE
	image_texture.stretch_mode = TextureRect.STRETCH_KEEP_ASPECT_CENTERED
	image_overlay.add_child(image_texture)
	image_close_button = Button.new()
	image_close_button.text = "X"
	image_close_button.position = Vector2(16, 16)
	image_close_button.custom_minimum_size = Vector2(44, 44)
	image_close_button.pressed.connect(func(): image_overlay.visible = false)
	image_overlay.add_child(image_close_button)


func _resolve_media_url(value: String) -> String:
	if value.begins_with("http://") or value.begins_with("https://"):
		return value
	var path := value if value.begins_with("/") else "/%s" % value
	var base := QuestionBankService.question_api_base_url
	var scheme_end := base.find("://")
	var path_start := base.find("/", scheme_end + 3)
	return "%s%s" % [base if path_start < 0 else base.substr(0, path_start), path]


func _clear_content() -> void:
	for child in content.get_children():
		child.queue_free()


func _clear_media_requests() -> void:
	for request in media_requests:
		if is_instance_valid(request): request.queue_free()
	media_requests.clear()


func _block_for_index(index: int) -> int:
	var consumed := 0
	for block in range(BLOCK_SIZES.size()):
		if index < consumed + BLOCK_SIZES[block]: return block
		consumed += BLOCK_SIZES[block]
	return BLOCK_SIZES.size() - 1


func _filter_accent(filter_name: String) -> Color:
	match filter_name:
		"incorrect": return Brand.MAGENTA
		"unanswered": return Brand.SLATE
		"flagged": return Brand.AMBER
		_: return Brand.ROYAL_BLUE


func _style_filter_chip(button: Button, accent: Color, dark: bool) -> void:
	Brand.apply_font(button)
	button.add_theme_font_size_override("font_size", 13)
	var normal := StyleBoxFlat.new()
	normal.bg_color = Color(accent, 0.06 if dark else 0.045)
	normal.border_color = Color(accent, 0.35)
	normal.set_border_width_all(1)
	normal.set_corner_radius_all(9)
	var hover := StyleBoxFlat.new()
	hover.bg_color = Color(accent, 0.18)
	hover.border_color = accent
	hover.set_border_width_all(1)
	hover.set_corner_radius_all(9)
	var pressed := StyleBoxFlat.new()
	pressed.bg_color = Color(accent, 0.62)
	pressed.border_color = accent
	pressed.set_border_width_all(1)
	pressed.set_corner_radius_all(9)
	button.add_theme_stylebox_override("normal", normal)
	button.add_theme_stylebox_override("hover", hover)
	button.add_theme_stylebox_override("pressed", pressed)
	button.add_theme_color_override("font_color", accent if dark else accent.darkened(0.1))
	button.add_theme_color_override("font_hover_color", accent)
	button.add_theme_color_override("font_pressed_color", Brand.DARK_TEXT)


func _style_gradient_button(button: Button) -> void:
	Brand.apply_font(button)
	button.add_theme_font_size_override("font_size", 15)
	button.add_theme_stylebox_override("normal", Brand.gradient_button_box())
	button.add_theme_stylebox_override("hover", Brand.gradient_button_box())
	button.add_theme_stylebox_override("pressed", Brand.gradient_button_box())
	button.add_theme_stylebox_override("disabled", Brand.gradient_button_box())
	button.add_theme_color_override("font_color", Color.WHITE)
	button.add_theme_color_override("font_hover_color", Color.WHITE)
	button.add_theme_color_override("font_disabled_color", Color(Color.WHITE, 0.5))


func _style_outline_button(button: Button, accent: Color, dark: bool) -> void:
	Brand.apply_font(button)
	button.add_theme_font_size_override("font_size", 14)
	var normal := StyleBoxFlat.new()
	normal.bg_color = Color(0, 0, 0, 0)
	normal.border_color = accent
	normal.set_border_width_all(1)
	normal.set_corner_radius_all(10)
	var hover := StyleBoxFlat.new()
	hover.bg_color = Color(accent, 0.12)
	hover.border_color = accent
	hover.set_border_width_all(1)
	hover.set_corner_radius_all(10)
	button.add_theme_stylebox_override("normal", normal)
	button.add_theme_stylebox_override("hover", hover)
	button.add_theme_stylebox_override("pressed", hover)
	button.add_theme_stylebox_override("disabled", normal)
	button.add_theme_color_override("font_color", accent if dark else accent.darkened(0.08))
	button.add_theme_color_override("font_hover_color", accent)
	button.add_theme_color_override("font_disabled_color", Color(accent, 0.4))


static func _matches_filter(filter_name: String, selected: String, correct: String, flagged: bool) -> bool:
	match filter_name:
		"incorrect": return selected != "" and selected != correct
		"unanswered": return selected == ""
		"flagged": return flagged
		_: return true