Refactor Table to use new SharedInventoryStation

abstract/shared_inventory_station.gd

@@ -0,0 +1,124 @@
+class_name SharedInventoryStation
+extends Station
+
+### Abstract 'class', should never be instantiated ###
+# Backbone for stations that need to know about neighboring stations of the
+# same kind (tables, belts).
+
+## Path to one Area3D probe per direction this station should watch for a
+## same-kind neighbor. Wired explicitly per concrete scene (e.g. a belt
+## wires one path, a table wires four).
+@export var probe_paths: Array[NodePath] = []
+
+## Resolved from probe_paths in ready().
+var probes: Array[Area3D] = []
+
+## Area3D probe -> the SharedInventoryStation neighbor detected through it
+## (or null if that direction is currently unoccupied).
+var neighbors: Dictionary = {}
+
+
+# The child station has to call super._enter_tree() for this to be called
+func _enter_tree() -> void:
+	super._enter_tree()
+	var properties: Array[NodePath] = [".:position", ".:rotation", ".:visible"]
+	for property_path in properties:
+		sync_config.add_property(property_path)
+		sync_config.property_set_spawn(property_path, false)
+		sync_config.property_set_replication_mode(property_path, SceneReplicationConfig.REPLICATION_MODE_ON_CHANGE)
+
+
+# The child station has to call super.ready() for this to be called
+func ready() -> void:
+	super.ready()
+	# Find probes
+	for path in probe_paths:
+		var probe := get_node_or_null(path) as Area3D
+		if probe:
+			probes.append(probe)
+		else:
+			SweetLogger.warning("{0} could not resolve neighbor probe at path {1}", [name, path])
+	if probes.is_empty():
+		SweetLogger.warning("{0} has no neighbor probes wired", [name])
+	for probe in probes:
+		neighbors[probe] = null
+		probe.body_entered.connect(_on_probe_body_entered.bind(probe))
+		probe.body_exited.connect(_on_probe_body_exited.bind(probe))
+	# Init leader state before any probe signal has a chance to fire
+	_broadcast_group_changed.call_deferred()
+
+
+## Cycle-safe search of the neighbor graph (handles circular belt/table loops)
+func get_connected_group() -> Array[SharedInventoryStation]:
+	var visited: Dictionary = {get_instance_id(): true}
+	var queue: Array[SharedInventoryStation] = [self]
+	var group: Array[SharedInventoryStation] = []
+	while not queue.is_empty():
+		var current: SharedInventoryStation = queue.pop_front()
+		group.append(current)
+		for neighbor in current.neighbors.values():
+			if neighbor and not visited.has(neighbor.get_instance_id()):
+				visited[neighbor.get_instance_id()] = true
+				queue.append(neighbor)
+	return group
+
+
+## Deterministic leader: smallest grid position, computed the same on every peer
+func is_group_leader() -> bool:
+	var leader: SharedInventoryStation = self
+	for member in get_connected_group():
+		if _grid_sort_key(member) < _grid_sort_key(leader):
+			leader = member
+	return leader == self
+
+
+static func _grid_sort_key(station: SharedInventoryStation) -> Vector2i:
+	var pos := station.global_position
+	return Vector2i(roundi(pos.x / Helper.SNAP_GRID_SIZE), roundi(pos.z / Helper.SNAP_GRID_SIZE))
+
+
+## Food items this station holds, exposed for neighbors to read; override for multi-zone stations
+func get_exposed_food_items() -> Array[FoodItem]:
+	var items: Array[FoodItem] = []
+	if snap_zone and snap_zone.picked_up_object:
+		var food_item := Helper.find_food_item(snap_zone.picked_up_object)
+		if food_item:
+			items.append(food_item)
+	return items
+
+
+## Every food item held anywhere in this station's connected group
+func get_group_food_items() -> Array[FoodItem]:
+	var items: Array[FoodItem] = []
+	for member in get_connected_group():
+		items.append_array(member.get_exposed_food_items())
+	return items
+
+
+func _on_probe_body_entered(body: Node3D, probe: Area3D) -> void:
+	var station := body as SharedInventoryStation
+	if not station or station == self:
+		return
+	neighbors[probe] = station
+	_broadcast_group_changed()
+
+
+func _on_probe_body_exited(body: Node3D, probe: Area3D) -> void:
+	var former: SharedInventoryStation = neighbors.get(probe)
+	if not former or body != former:
+		return
+	neighbors[probe] = null
+	# former is no longer reachable from self, so it needs telling separately
+	former._broadcast_group_changed()
+	_broadcast_group_changed()
+
+
+## Notifies every member of this station's current connected group (not just the two that changed)
+func _broadcast_group_changed() -> void:
+	for member in get_connected_group():
+		member._on_group_changed()
+
+
+## Virtual hook: override to react to this station's group membership/leadership changing
+func _on_group_changed() -> void:
+	pass