extends CanvasLayer
## In-game HUD: crosshair, interaction prompt, hotbar, toasts, and the
## inventory screen. Rendering only: it reads player state and forwards
## clicks to Actions.

const UITheme = preload("res://scripts/ui/theme.gd")
const SlotScript = preload("res://scripts/ui/slot.gd")
const InventoryScreen = preload("res://scripts/ui/inventory_screen.gd")
const PauseMenu = preload("res://scripts/ui/pause_menu.gd")

var player: CharacterBody3D
var _prompt: Label
var _held_name: Label
var _hotbar: Array = []
var _toasts: VBoxContainer
var _screen: Control
var _menu: Control

func bind(p: CharacterBody3D) -> void:
	player = p
	layer = 5
	var root := Control.new()
	root.set_anchors_preset(Control.PRESET_FULL_RECT)
	root.mouse_filter = Control.MOUSE_FILTER_IGNORE
	add_child(root)

	# Crosshair.
	var dot := ColorRect.new()
	dot.color = Color(1, 1, 1, 0.8)
	dot.size = Vector2(4, 4)
	dot.set_anchors_preset(Control.PRESET_CENTER)
	dot.position -= Vector2(2, 2)
	dot.mouse_filter = Control.MOUSE_FILTER_IGNORE
	root.add_child(dot)

	_prompt = UITheme.label("", 18)
	_prompt.set_anchors_and_offsets_preset(Control.PRESET_CENTER)
	_prompt.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
	_prompt.grow_horizontal = Control.GROW_DIRECTION_BOTH
	_prompt.offset_top = 28
	_prompt.offset_bottom = 56
	root.add_child(_prompt)

	# Hotbar.
	var bar := HBoxContainer.new()
	bar.add_theme_constant_override("separation", 6)
	bar.set_anchors_and_offsets_preset(Control.PRESET_CENTER_BOTTOM)
	bar.grow_horizontal = Control.GROW_DIRECTION_BOTH
	bar.grow_vertical = Control.GROW_DIRECTION_BEGIN
	bar.offset_bottom = -18
	bar.mouse_filter = Control.MOUSE_FILTER_IGNORE
	for i in range(8):
		var s: Panel = SlotScript.new(i, 64, str(i + 1))
		s.mouse_filter = Control.MOUSE_FILTER_IGNORE
		bar.add_child(s)
		_hotbar.append(s)
	root.add_child(bar)

	_held_name = UITheme.label("", 15, UITheme.TEXT_DIM)
	_held_name.set_anchors_and_offsets_preset(Control.PRESET_CENTER_BOTTOM)
	_held_name.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
	_held_name.grow_horizontal = Control.GROW_DIRECTION_BOTH
	_held_name.offset_top = -112
	_held_name.offset_bottom = -90
	root.add_child(_held_name)

	_toasts = VBoxContainer.new()
	_toasts.set_anchors_and_offsets_preset(Control.PRESET_BOTTOM_RIGHT)
	_toasts.grow_horizontal = Control.GROW_DIRECTION_BEGIN
	_toasts.grow_vertical = Control.GROW_DIRECTION_BEGIN
	_toasts.offset_right = -24
	_toasts.offset_bottom = -110
	_toasts.alignment = BoxContainer.ALIGNMENT_END
	_toasts.mouse_filter = Control.MOUSE_FILTER_IGNORE
	root.add_child(_toasts)

	_screen = InventoryScreen.new()
	root.add_child(_screen)
	_screen.bind(player)

	_menu = PauseMenu.new()
	root.add_child(_menu)
	_menu.bind(player)
	process_mode = Node.PROCESS_MODE_ALWAYS   # so ESC works while paused
	_screen.process_mode = Node.PROCESS_MODE_PAUSABLE

	player.inventory.changed.connect(_refresh)
	player.selected_changed.connect(_refresh)
	player.inventory_requested.connect(_on_inventory_requested)
	player.hands.prompt_changed.connect(func(t): _prompt.text = t)
	Actions.notify.connect(toast)
	ItemDB.icons_ready.connect(_refresh)
	_refresh()

func _on_inventory_requested(container: Node) -> void:
	if not _screen.is_open():
		_screen.open(container)

## ESC: close the inventory if it's open, otherwise toggle the pause menu.
func _input(event: InputEvent) -> void:
	if event is InputEventKey and event.pressed and not event.echo and event.keycode == KEY_ESCAPE:
		if _screen.is_open():
			_screen.close()
		elif _menu.is_open():
			_menu.back()
		else:
			_menu.open()
		get_viewport().set_input_as_handled()

func _unhandled_input(event: InputEvent) -> void:
	if _menu.is_open():
		return
	if event.is_action_pressed("inventory") and not _screen.is_open():
		_screen.open(null)
		get_viewport().set_input_as_handled()

func _refresh() -> void:
	for i in range(_hotbar.size()):
		_hotbar[i].set_stack(player.inventory.get_slot(i))
		_hotbar[i].set_selected(i == player.selected)
	var id: String = player.held_item_id()
	_held_name.text = ItemDB.item_name(id) if not id.is_empty() else ""

func toast(text: String) -> void:
	# Merge repeated "+N Item" toasts so chopping doesn't spam the corner.
	for c in _toasts.get_children():
		if c.get_meta("base", "") == text:
			c.modulate.a = 1.0
			return
	var l := UITheme.label(text, 17)
	l.horizontal_alignment = HORIZONTAL_ALIGNMENT_RIGHT
	l.set_meta("base", text)
	_toasts.add_child(l)
	while _toasts.get_child_count() > 6:
		_toasts.get_child(0).free()
	var tw := l.create_tween()
	tw.tween_interval(2.2)
	tw.tween_property(l, "modulate:a", 0.0, 0.8)
	tw.tween_callback(l.queue_free)