extends Control

## D-065: Inventory grid — 3x3 slots, bottom-right, 40x40px icons.
## No empty slots displayed — icons appear only when items are carried.
## 1-9 hotkeys for direct slot access. Reads from GameState.player_inventory.
## Lives on UILayer (z-layer 7).

signal item_selected(slot: int, item_id: int)

const SLOT_SIZE := 40
const SLOT_GAP := 4
const GRID_COLS := 3
const GRID_ROWS := 3
const MAX_SLOTS := 9

const SLOT_BG := Color(0.1, 0.1, 0.14, 0.6)
const SLOT_BORDER := Color(0.3, 0.3, 0.38, 0.8)
const SLOT_ACTIVE := Color("#c8d0e0")
const SLOT_TEXT := Color("#c8d0e0")
const SLOT_TEXT_DIM := Color("#8b8ba0")
const HOTKEY_SIZE := 10

var _slots: Array = []  # [{item_id, name, slot}] from GameState
var _slot_nodes: Array[Control] = []
var _selected_slot: int = -1


func _ready() -> void:
	mouse_filter = Control.MOUSE_FILTER_IGNORE
	_build_grid()
	visible = false


func _build_grid() -> void:
	for node in _slot_nodes:
		if is_instance_valid(node):
			node.queue_free()
	_slot_nodes.clear()

	var grid_w: float = GRID_COLS * SLOT_SIZE + (GRID_COLS - 1) * SLOT_GAP
	var grid_h: float = GRID_ROWS * SLOT_SIZE + (GRID_ROWS - 1) * SLOT_GAP

	# Position grid at bottom-right with margin
	custom_minimum_size = Vector2(grid_w, grid_h)
	size = Vector2(grid_w, grid_h)


func update_from_state() -> void:
	_slots = GameState.player_inventory.duplicate()

	if _slots.is_empty():
		visible = false
		return

	visible = true
	queue_redraw()


func _draw() -> void:
	if _slots.is_empty():
		return

	for item in _slots:
		var slot_idx: int = item.get("slot", 0)
		if slot_idx < 0 or slot_idx >= MAX_SLOTS:
			continue

		var col: int = slot_idx % GRID_COLS
		var row: int = slot_idx / GRID_COLS
		var pos := Vector2(col * (SLOT_SIZE + SLOT_GAP), row * (SLOT_SIZE + SLOT_GAP))
		var rect := Rect2(pos, Vector2(SLOT_SIZE, SLOT_SIZE))

		# Slot background
		draw_rect(rect, SLOT_BG)
		# Border
		draw_rect(rect, SLOT_BORDER, false, 1.0)

		# Selected highlight
		if slot_idx == _selected_slot:
			draw_rect(rect, SLOT_ACTIVE, false, 2.0)

		# Item name (truncated, centered)
		var item_name: String = item.get("name", "?")
		if item_name.length() > 5:
			item_name = item_name.substr(0, 4) + "."
		var font := ThemeDB.fallback_font
		var font_size := 11
		var text_size := font.get_string_size(item_name, HORIZONTAL_ALIGNMENT_CENTER, -1, font_size)
		var text_pos := (
			pos + Vector2((SLOT_SIZE - text_size.x) / 2.0, SLOT_SIZE / 2.0 + text_size.y / 4.0)
		)
		draw_string(font, text_pos, item_name, HORIZONTAL_ALIGNMENT_LEFT, -1, font_size, SLOT_TEXT)

		# Hotkey number (top-left corner)
		var hotkey := str(slot_idx + 1)
		draw_string(
			font,
			pos + Vector2(3, HOTKEY_SIZE + 2),
			hotkey,
			HORIZONTAL_ALIGNMENT_LEFT,
			-1,
			HOTKEY_SIZE,
			SLOT_TEXT_DIM
		)


func _unhandled_input(event: InputEvent) -> void:
	if not visible:
		return
	if event is InputEventKey and event.pressed and not event.echo:
		var key: int = event.physical_keycode
		# 1-9 hotkeys (Key_1 = 49, Key_9 = 57)
		if key >= KEY_1 and key <= KEY_9:
			var slot_idx: int = key - KEY_1
			_select_slot(slot_idx)
			get_viewport().set_input_as_handled()


func _select_slot(slot_idx: int) -> void:
	# Find item in this slot
	for item in _slots:
		if item.get("slot", -1) == slot_idx:
			_selected_slot = slot_idx
			item_selected.emit(slot_idx, item.get("item_id", -1))
			queue_redraw()
			return
	# No item in slot — deselect
	_selected_slot = -1
	queue_redraw()


# -- Public API ---------------------------------------------------------------


func get_slot_count() -> int:
	return _slots.size()


func get_selected_slot() -> int:
	return _selected_slot


func get_item_at_slot(slot_idx: int) -> Dictionary:
	for item in _slots:
		if item.get("slot", -1) == slot_idx:
			return item
	return {}