Compose buildings from definitions and capabilities

GameState.gd

@@ -2,6 +2,7 @@ extends Node
 
 const INVENTORY = preload("res://Inventory.gd")
 const RESOURCE_DEFINITIONS = preload("res://ResourceDefinitions.gd")
+const BUILDING_DEFINITIONS = preload("res://BuildingDefinitions.gd")
 
 
 # Autoload singleton - the one thing that survives change_scene_to_file()
@@ -104,7 +105,7 @@ func building_inventory(id: int) -> RefCounted:
 	var building: Dictionary = find_building(id)
 	if building.is_empty():
 		return null
-	if building.type == BUILDING_MOTHERSHIP:
+	if building_has_capability(building, "bank"):
 		return bank_inventory
 	return _inventory_for_record(building)
 
@@ -313,11 +314,6 @@ func unlock(id: String) -> bool:
 
 
 func is_building_unlocked(type: String) -> bool:
-	# The mothership is always buildable: it is where research happens, so
-	# locking it would leave a player with no mothership unable to ever get
-	# one.
-	if type == BUILDING_MOTHERSHIP:
-		return true
 	for node in SKILL_TREE:
 		if node.get("unlocks", "") == type:
 			return is_unlocked(node.id)
@@ -392,6 +388,13 @@ func find_building(id: int) -> Dictionary:
 	return {}
 
 
+func building_has_capability(building: Dictionary, capability: String) -> bool:
+	if building.is_empty():
+		return false
+	var definition: Resource = BUILDING_DEFINITIONS.get_definition(String(building.type))
+	return definition != null and capability in definition.capabilities
+
+
 # --- vessel types and their upgrades (#5) ---------------------------------
 
 # The three things that can be flying around. The first and last double as
@@ -494,7 +497,7 @@ signal vessel_upgraded(upgrade_id: String)
 
 func has_ship_lab() -> bool:
 	for b in buildings:
-		if b.type == BUILDING_SHIP_LAB:
+		if building_has_capability(b, "vessel_research"):
 			return true
 	return false
 
@@ -627,9 +630,8 @@ func product_cost(product: String) -> int:
 
 
 func can_produce(type: String) -> bool:
-	# Only the ship crafter builds anything. The hub STATIONS transporters,
-	# it does not make them (#12).
-	return type == BUILDING_SHIP_CRAFTER
+	var definition: Resource = BUILDING_DEFINITIONS.get_definition(type)
+	return definition != null and "production" in definition.capabilities
 
 
 func building_stock(id: int) -> int:
@@ -777,7 +779,7 @@ func _advance_production(delta: float) -> void:
 
 func queue_lab_research(lab_id: int, upgrade_id: String) -> bool:
 	var lab: Dictionary = find_building(lab_id)
-	if lab.is_empty() or lab.type != BUILDING_SHIP_LAB or upgrade_id == "":
+	if not building_has_capability(lab, "vessel_research") or upgrade_id == "":
 		return false
 	var orders: Array = lab.get("research_orders", [])
 	if not orders.is_empty() or (upgrade_id != UNLOCK_SHIELD_VESSEL and upgrade_maxed(upgrade_id)):
@@ -795,7 +797,7 @@ func lab_research_order(lab_id: int) -> Dictionary:
 
 func _advance_lab_research(delta: float) -> void:
 	for lab in buildings:
-		if lab.type != BUILDING_SHIP_LAB:
+		if not building_has_capability(lab, "vessel_research"):
 			continue
 		var orders: Array = lab.get("research_orders", [])
 		if orders.is_empty():
@@ -841,6 +843,13 @@ func has_mothership() -> bool:
 	return get_mothership_position() != null
 
 
+func has_building_of_type(type: String) -> bool:
+	for building in buildings:
+		if building.type == type:
+			return true
+	return false
+
+
 func remove_buildings_of_type(type: String) -> int:
 	var kept: Array = []
 	var removed: int = 0
@@ -857,7 +866,7 @@ func get_mothership_position() -> Variant:
 	# Where a wiped-out fleet gets rebuilt. Returns null when no mothership
 	# has been built yet, so the caller can fall back to the world origin.
 	for b in buildings:
-		if b.type == BUILDING_MOTHERSHIP:
+		if building_has_capability(b, "bank"):
 			return b.position
 	return null
 
@@ -1017,7 +1026,7 @@ func hub_capacity() -> int:
 func hub_count() -> int:
 	var n: int = 0
 	for b in buildings:
-		if b.type == BUILDING_TRANSPORT_HUB:
+		if building_has_capability(b, "transport_hub"):
 			n += 1
 	return n
 
@@ -1056,7 +1065,7 @@ func nearest_hub_to(at: Vector2) -> Dictionary:
 	var best: Dictionary = {}
 	var best_d: float = INF
 	for b in buildings:
-		if b.type != BUILDING_TRANSPORT_HUB:
+		if not building_has_capability(b, "transport_hub"):
 			continue
 		var d: float = at.distance_squared_to(b.position)
 		if d < best_d: