# (c) 2023-present Eroax
# (c) 2023-present Yagich
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
extends MarginContainer
class_name AddNodeMenu

## A menu for adding nodes with a search bar.

@onready var search_line_edit: LineEdit = %SearchLineEdit
@onready var scroll_content_container: VBoxContainer = %ScrollContentContainer
@onready var scroll_container: ScrollContainer = $VBoxContainer/ScrollContainer

## The categories currently shown in the menu.
var categories: Dictionary = {} # Dictionary[String, Category]
## A list of categories to remember the collapsed state of so they remain collapsed when the search list is rebuilt.
var collapsed_categories: Array[String]

## Emitted when a node is selected either by clicking on it or pressing [constant @GlobalScope.KEY_ENTER] while the [member search_line_edit] is focused.
signal node_selected(type: String)


func _ready() -> void:
	search("")


## Add a new category to the menu.
func add_category(category_name: String) -> void:
	var c := Category.new(NodeDB.get_category_capitalization(category_name))
	categories[category_name] = c
	scroll_content_container.add_child(c)
	c.collapse_toggled.connect(_on_category_collapse_toggled.bind(category_name))
	c.item_pressed.connect(
		func(item: int):
			node_selected.emit(c.get_item_metadata(item, "type"))
	)
	c.item_favorite_button_toggled.connect(
		func(item: int, toggled: bool):
			NodeDB.set_node_favorite(c.get_item_metadata(item, "type"), toggled)
	)


## Add an item to a category.
func add_category_item(category: String, item: String, tooltip: String = "", favorite: bool = false) -> void:
	var c: Category = categories[category]
	c.add_item(item, tooltip, favorite)


## Wrapper around [method add_category_item] and [method add_category]. Adds an item to a [param category], creating the category if it doesn't exist yet.
func add_item(category: String, item: String, tooltip: String = "", favorite: bool = false) -> void:
	if !categories.has(category):
		add_category(category)

	add_category_item(category, item, tooltip, favorite)


## Get a [AddNodeMenu.Category] node by its' identifier.
func get_category(category: String) -> Category:
	return categories[category]


## Focus the search bar and select all its' text.
func focus_search_bar() -> void:
	search_line_edit.select_all()
	search_line_edit.grab_focus()


## Searches for a node using [SearchProvider] and puts the results as items.
func search(text: String) -> void:
	scroll_content_container.get_children().map(func(c: Node): c.queue_free())
	categories.clear()

	var search_results := SearchProvider.search(text)
	if search_results.is_empty():
		return

	for nd in search_results:
		add_item(nd.category, nd.name, nd.description, NodeDB.is_node_favorite(nd.type))
		var c := get_category(nd.category)
		c.set_item_metadata(c.get_item_count() - 1, "type", nd.type)
		c.set_item_metadata(c.get_item_count() - 1, "node_descriptor", weakref(nd))
		c.set_collapsed(nd.category in collapsed_categories)

	get_category(categories.keys()[0]).highlight_item(0)


## Callback for [member search_line_edit]'s input events. Handles highlighting items when navigating with up/down arrow keys.
func _on_search_line_edit_gui_input(event: InputEvent) -> void:
	if event.is_action_pressed("ui_down"):
		if scroll_content_container.get_child_count() == 0:
			return

		search_line_edit.accept_event()
		var category: Category
		for i: String in categories:
			var c: Category = categories[i]
			if c.get_highlighted_item() != -1:
				category = c
				break
		var item := category.get_highlighted_item()
		if item + 1 == category.get_item_count():
			# reached the end of items in the current category
			category.unhighlight_all()

			var nc := get_next_visible_category(category.get_index())
			nc.highlight_item(0)
			scroll_container.ensure_control_visible(nc.get_child(0))
			return

		category.highlight_item(item + 1)
		scroll_container.ensure_control_visible(category.get_child(item + 1))

	if event.is_action_pressed("ui_up"):
		if scroll_content_container.get_child_count() == 0:
			return

		search_line_edit.accept_event()
		var category: Category
		for i: String in categories:
			var c: Category = categories[i]
			if c.get_highlighted_item() != -1:
				category = c
				break
		var item := category.get_highlighted_item()
		if item - 1 == -1:
			# reached the beginning of items in the current category
			category.unhighlight_all()

			var nc := get_previous_visible_category(category.get_index())
			nc.highlight_item(nc.get_item_count() - 1)
			scroll_container.ensure_control_visible(nc.get_child(nc.get_item_count() - 1))
			return

		category.highlight_item(item - 1)
		scroll_container.ensure_control_visible(category.get_child(item - 1))


## Returns the next uncollapsed category, starting from index [code]at[/code], wrapping around if no other
## categories are uncollapsed.
func get_next_visible_category(at: int) -> Category:
	var i := at
	var s := 0

	while s < scroll_content_container.get_child_count():
		i = (i + 1) % scroll_content_container.get_child_count()
		if !(scroll_content_container.get_child(i) as Category).is_collapsed():
			return scroll_content_container.get_child(i)
		s += 1

	return scroll_content_container.get_child(at)


## Returns the previous uncollapsed category, starting from index [code]at[/code], wrapping around if no other
## categories are uncollapsed.
func get_previous_visible_category(at: int) -> Category:
	var i := at
	var s := 0

	while s < scroll_content_container.get_child_count():
		i = (i - 1) % scroll_content_container.get_child_count()
		if !(scroll_content_container.get_child(i) as Category).is_collapsed():
			return scroll_content_container.get_child(i)
		s += 1

	return scroll_content_container.get_child(at)


## Callback for [member search_line_edit]. Handles emitting [signal node_selected]
func _on_search_line_edit_text_submitted(_new_text: String) -> void:
	if scroll_content_container.get_child_count() == 0:
		return

	var category: Category
	for i: String in categories:
			var c: Category = categories[i]
			if c.get_highlighted_item() != -1:
				category = c
				break
	node_selected.emit(category.get_item_metadata(category.get_highlighted_item(), "type"))


func _on_category_collapse_toggled(collapsed: bool, category: String) -> void:
	if collapsed:
		collapsed_categories.append(category)
	else:
		collapsed_categories.erase(category)

## A collapsible item menu.
##
## An analog to [Tree] and [ItemList] made with nodes. Allows collapsing its
## children [AddNodeMenu.CategoryItem] nodes and highlighting them.[br]
## [b]Note:[/b] only one [AddNodeMenu.CategoryItem] can be highlighted at any time.
class Category extends VBoxContainer:
	const COLLAPSE_ICON := preload("res://graph_node_renderer/textures/collapse-icon.svg")
	const COLLAPSE_ICON_COLLAPSED := preload("res://graph_node_renderer/textures/collapse-icon-collapsed.svg")
	var collapse_button: Button

	## Emitted when a child item has been pressed.
	signal item_pressed(item: int)
	## Emitted when a child item's favorite button has been pressed.
	signal item_favorite_button_toggled(item: int, toggled: bool)
	## Emitted when the category's collapsed state has been toggled.
	signal collapse_toggled(collapsed: bool)


	func _init(p_name: String) -> void:
		collapse_button = Button.new()
		collapse_button.alignment = HORIZONTAL_ALIGNMENT_LEFT
		collapse_button.icon = COLLAPSE_ICON
		collapse_button.toggle_mode = true
		collapse_button.flat = true
		collapse_button.size_flags_vertical = Control.SIZE_EXPAND_FILL
		collapse_button.text = p_name
		collapse_button.toggled.connect(
			func(toggled: bool):
				collapse_toggled.emit(toggled)
		)
		add_child(collapse_button, false, Node.INTERNAL_MODE_FRONT)

		renamed.connect(func():
			collapse_button.name = name
		)
		collapse_button.toggled.connect(set_collapsed)


	## If [param collapsed] is [code]true[/code], collapses the category, hiding its children.
	func set_collapsed(collapsed: bool) -> void:
		collapse_button.icon = COLLAPSE_ICON_COLLAPSED if collapsed else COLLAPSE_ICON
		collapse_button.set_pressed_no_signal(collapsed)
		for c: CategoryItem in get_children():
			c.visible = !collapsed


	## Add an item to the category.
	func add_item(p_name: String, p_tooltip: String, p_favorite: bool = false) -> void:
		var item := CategoryItem.new(p_name, p_tooltip, p_favorite)
		item.favorite_toggled.connect(
			func(toggled: bool):
				item_favorite_button_toggled.emit(item.get_index(), toggled)
		)
		item.pressed.connect(
			func():
				item_pressed.emit(item.get_index())
		)
		add_child(item)


	## Set an item's metadata at index [param item].
	func set_item_metadata(item: int, key: StringName, metadata: Variant) -> void:
		get_child(item).set_meta(key, metadata)


	## Retrieve an item's metadata at index [param item].
	func get_item_metadata(item: int, key: StringName) -> Variant:
		return get_child(item).get_meta(key)


	## Get the amount of items in this category.
	func get_item_count() -> int:
		return get_child_count()


	## Toggle an item at index [param item]'s favorite state.
	func set_item_favorite(item:int, favorite: bool) -> void:
		var _item := get_child(item) as CategoryItem
		_item.set_favorite(favorite)


	## Returns [code]true[/code] if the item at [param item] is marked as favorite.
	func is_item_favorite(item: int) -> bool:
		var _item := get_child(item) as CategoryItem
		return _item.is_favorite()


	## Highlight item at index [item], and unhighlight all other items.
	func highlight_item(item: int) -> void:
		for c: CategoryItem in get_children():
			c.set_highlighted(c.get_index() == item)


	## Unhighlight all items.
	func unhighlight_all() -> void:
		for c: CategoryItem in get_children():
			c.set_highlighted(false)


	## Returns the index of the currently highlighted item. Returns [code]-1[/code] if no item is highlighted in this category.
	func get_highlighted_item() -> int:
		for c: CategoryItem in get_children():
			if c.is_highlighted:
				return c.get_index()

		return -1


	func is_collapsed() -> bool:
		return collapse_button.button_pressed


## Represents an item in a [AddNodeMenu.Category].
##
## A selectable and highlightable category item with a favorite button.
class CategoryItem extends HBoxContainer:
	const FAVORITE_ICON := preload("res://graph_node_renderer/textures/favorite-icon.svg")
	const NON_FAVORITE_ICON := preload("res://graph_node_renderer/textures/non-favorite-icon.svg")
	const ITEM_MARGIN := 16

	## The stylebox to use if this item is highlighted.
	var highlighted_stylebox := StyleBoxFlat.new()

	var is_highlighted: bool

	var fav_button: Button
	var name_button: Button
	var panel: PanelContainer

	## Emitted when this item has been pressed.
	signal pressed
	## Emitted when this item's [member fav_button] has been pressed.
	signal favorite_toggled(toggled: bool)


	func _init(p_name: String, p_tooltip: String, p_favorite: bool) -> void:
		fav_button = Button.new()
		fav_button.icon = FAVORITE_ICON if p_favorite else NON_FAVORITE_ICON
		fav_button.toggle_mode = true
		fav_button.set_pressed_no_signal(p_favorite)
		fav_button.flat = true
		fav_button.toggled.connect(
			func(toggled: bool):
				favorite_toggled.emit(toggled)
		)
		fav_button.toggled.connect(set_favorite)

		name_button = Button.new()
		name_button.size_flags_horizontal = Control.SIZE_EXPAND_FILL
		name_button.text = p_name
		name_button.flat = true
		name_button.alignment = HORIZONTAL_ALIGNMENT_LEFT
		name_button.tooltip_text = p_tooltip
		name_button.pressed.connect(
			func():
				pressed.emit()
		)

		var mc := MarginContainer.new()
		mc.add_theme_constant_override(&"margin_left", ITEM_MARGIN)

		panel = PanelContainer.new()
		panel.size_flags_horizontal = Control.SIZE_EXPAND_FILL
		panel.add_theme_stylebox_override(&"panel", highlighted_stylebox)
		highlighted_stylebox.bg_color = Color(0.0, 0.0, 0.0, 0.15)
		panel.self_modulate = Color.TRANSPARENT

		var inner_hb := HBoxContainer.new()
		inner_hb.add_child(fav_button)
		inner_hb.add_child(name_button)
		panel.add_child(inner_hb)

		add_child(mc)
		add_child(panel)


	## Toggle this item's favorite state.
	func set_favorite(favorite: bool) -> void:
		fav_button.icon = FAVORITE_ICON if favorite else NON_FAVORITE_ICON
		fav_button.set_pressed_no_signal(favorite)


	## Returns [code]true[/code] if this item is marked as favorite.
	func is_favorite() -> bool:
		return fav_button.icon == FAVORITE_ICON


	## Toggle this item's highlighted state.
	func set_highlighted(highlighted: bool) -> void:
		is_highlighted = highlighted
		if highlighted:
			panel.self_modulate = Color.WHITE
		else:
			panel.self_modulate = Color.TRANSPARENT