feat(inventory): hotbar + inventory UI + 5 crafting recipes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/inventory/Inventory.gd

@@ -0,0 +1,93 @@
+class_name Inventory
+extends RefCounted
+
+const MAX_STACK: int = 64
+const TOTAL_SLOTS: int = 36
+const HOTBAR_SIZE: int = 9
+
+signal inventory_changed
+
+var slots: Array = []
+var selected_hotbar: int = 0
+
+
+func _init() -> void:
+	slots.resize(TOTAL_SLOTS)
+	for i: int in range(TOTAL_SLOTS):
+		slots[i] = null
+
+
+func add_item(item_id: int, count: int = 1) -> int:
+	var remaining: int = count
+	# First pass: stack into existing slots
+	for i: int in range(TOTAL_SLOTS):
+		if remaining <= 0:
+			break
+		if slots[i] != null and slots[i]["item_id"] == item_id:
+			var space: int = MAX_STACK - slots[i]["count"]
+			if space > 0:
+				var add_amount: int = mini(space, remaining)
+				slots[i]["count"] += add_amount
+				remaining -= add_amount
+	# Second pass: fill empty slots
+	for i: int in range(TOTAL_SLOTS):
+		if remaining <= 0:
+			break
+		if slots[i] == null:
+			var add_amount: int = mini(MAX_STACK, remaining)
+			slots[i] = {"item_id": item_id, "count": add_amount}
+			remaining -= add_amount
+	inventory_changed.emit()
+	return remaining
+
+
+func remove_item_from_slot(slot_index: int, count: int = 1) -> bool:
+	if slot_index < 0 or slot_index >= TOTAL_SLOTS:
+		return false
+	if slots[slot_index] == null:
+		return false
+	if slots[slot_index]["count"] < count:
+		return false
+	slots[slot_index]["count"] -= count
+	if slots[slot_index]["count"] <= 0:
+		slots[slot_index] = null
+	inventory_changed.emit()
+	return true
+
+
+func get_selected_item() -> Variant:
+	return slots[selected_hotbar]
+
+
+func scroll_hotbar(direction: int) -> void:
+	selected_hotbar = (selected_hotbar + direction + HOTBAR_SIZE) % HOTBAR_SIZE
+	inventory_changed.emit()
+
+
+func has_items(requirements: Array) -> bool:
+	for req: Dictionary in requirements:
+		var needed: int = req["count"]
+		for i: int in range(TOTAL_SLOTS):
+			if slots[i] != null and slots[i]["item_id"] == req["item_id"]:
+				needed -= slots[i]["count"]
+		if needed > 0:
+			return false
+	return true
+
+
+func consume_items(requirements: Array) -> bool:
+	if not has_items(requirements):
+		return false
+	for req: Dictionary in requirements:
+		var to_consume: int = req["count"]
+		for i: int in range(TOTAL_SLOTS):
+			if to_consume <= 0:
+				break
+			if slots[i] != null and slots[i]["item_id"] == req["item_id"]:
+				var take: int = mini(slots[i]["count"], to_consume)
+				slots[i]["count"] -= take
+				to_consume -= take
+				if slots[i]["count"] <= 0:
+					slots[i] = null
+	inventory_changed.emit()
+	return true