Typed owed vessels, ship lab building type, shield vessel gate

Groundwork for #5. vessels_owed carries the VESSEL TYPE rather than a
bare count, so a shield vessel finishing while the player is on a planet
comes back as a shield vessel. Fleet.add_ship takes a type, and vessels
already flying are re-statted when an upgrade is researched.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

BuildController.gd

@@ -557,7 +557,7 @@ func _refresh_craft_status() -> void:
 	# A full fleet cannot take another vessel, so the order would be refused.
 	# Showing that on the button is the difference between "not available yet"
 	# and a button that looks live and silently does nothing when pressed.
-	var room: bool = fleet.ships.size() + GameState.ships_owed \
+	var room: bool = fleet.ships.size() + GameState.vessels_owed.size() \
 		+ GameState.pending_orders_of(craft_building_id, GameState.PRODUCT_SHIP) \
 		< GameState.max_fleet_size()
 	craft_interceptor_button.enabled = room
@@ -568,7 +568,7 @@ func _refresh_craft_status() -> void:
 		craft_status.text += "      Fleet %d/%d" % [fleet.ships.size(), GameState.max_fleet_size()]
 	else:
 		var queued_ships: int = GameState.pending_orders_of(craft_building_id, GameState.PRODUCT_SHIP)
-		var owed: int = GameState.ships_owed + queued_ships
+		var owed: int = GameState.vessels_owed.size() + queued_ships
 		var pending_note: String = "" if owed == 0 else " (%d already on order)" % owed
 		craft_status.text = "No room in the fleet: %d/%d%s - research capacity at the mothership\n%s" % [
 			fleet.ships.size(), GameState.max_fleet_size(), pending_note, craft_status.text
@@ -586,8 +586,8 @@ func _on_craft_interceptor() -> void:
 	if craft_building_id == 0:
 		return
 	# Still refused when there is nowhere to put the vessel - queueing an
-	# order that can never be delivered would just bank ships_owed forever.
+	# order that can never be delivered would just bank vessels_owed forever.
-	if fleet.ships.size() + GameState.ships_owed \
+	if fleet.ships.size() + GameState.vessels_owed.size() \
 			+ GameState.pending_orders_of(craft_building_id, GameState.PRODUCT_SHIP) \
 			>= GameState.max_fleet_size():
 		_say("Fleet is full (%d slots)" % GameState.max_fleet_size())

Fleet.gd

@@ -32,6 +32,18 @@ var anchor: Vector2 = Vector2.ZERO
 var steer_direction: Vector2 = Vector2.ZERO
 
 
+func _ready() -> void:
+	# Researching a vessel upgrade improves the ships already flying, not
+	# just the next one built (#5).
+	GameState.vessel_upgraded.connect(_on_vessel_upgraded)
+
+
+func _on_vessel_upgraded(_id: String) -> void:
+	for ship in ships:
+		if is_instance_valid(ship):
+			ship.apply_vessel_stats()
+
+
 func spawn_ships(count: int, center: Vector2 = Vector2.ZERO) -> void:
 	for ship in ships:
 		if is_instance_valid(ship):
@@ -55,13 +67,16 @@ func spawn_ships(count: int, center: Vector2 = Vector2.ZERO) -> void:
 	fleet_target = center
 
 
-func add_ship() -> bool:
+func add_ship(vessel_type: String = GameState.VESSEL_INTERCEPTOR) -> bool:
 	# Adds one vessel in the next free formation slot (bought from a ship
 	# crafter). Returns false when the wedge is already full.
 	if ships.size() >= GameState.max_fleet_size():
 		return false
 	var offset: Vector2 = GameState.formation[ships.size()]
 	var ship: Area2D = ship_scene.instantiate()
+	# Before add_child, so Ship._ready() builds the right vessel - the shield
+	# ring is created there and only for a shield vessel.
+	ship.vessel_type = vessel_type
 	# From the formation origin, not the centroid: with a lopsided layout the
 	# centroid is already displaced by the average offset, so adding the new
 	# ship's own offset to it would drop it well outside the wedge.
@@ -128,12 +143,12 @@ func _process(delta: float) -> void:
 func _claim_owed_ships() -> void:
 	# Production completes in the GameState autoload, which may well happen
 	# while the player is on a planet's surface with no Fleet node in
-	# existence to hand a vessel to. Those ships wait as `ships_owed` until a
+	# existence to hand a vessel to. Those vessels wait in `vessels_owed`
 	# fleet with room can take them.
-	while GameState.ships_owed > 0 and ships.size() < GameState.max_fleet_size():
+	while not GameState.vessels_owed.is_empty() and ships.size() < GameState.max_fleet_size():
-		if not add_ship():
+		if not add_ship(String(GameState.vessels_owed[0])):
 			return
-		GameState.ships_owed -= 1
+		GameState.vessels_owed.pop_front()
 
 
 func _assign_slot_targets() -> void:

GameState.gd

@@ -104,10 +104,13 @@ const BUILDING_EXTRACTOR: String = "extractor"
 # Hosts the transport vessels that supply other buildings (#18). Built in
 # space like the rest; it is the transporters (#19) that do the moving.
 const BUILDING_TRANSPORT_HUB: String = "transport_hub"
+# Where vessel types are researched and new ones unlocked (#5).
+const BUILDING_SHIP_LAB: String = "ship_lab"
 
 const COMMAND_CENTER_COST: int = 15
 const EXTRACTOR_COST: int = 25
 const TRANSPORT_HUB_COST: int = 30
+const SHIP_LAB_COST: int = 35
 
 var buildings: Array = []
 
@@ -145,6 +148,11 @@ const SKILL_TREE: Array = [
 		"x": 0.18, "unlocks": BUILDING_TRANSPORT_HUB,
 		"desc": "Build transport hubs, which supply your other buildings with ore.",
 	},
+	{
+		"id": "vessel_science", "name": "Vessel Science", "cost": 35, "requires": "shipyards",
+		"x": 0.62, "unlocks": BUILDING_SHIP_LAB,
+		"desc": "Build ship labs, where each vessel type is upgraded and new ones unlocked.",
+	},
 	{
 		"id": "freight_yards", "name": "Freight Yards", "cost": 80, "requires": "freight",
 		"x": 0.05, "hub_bonus": 1,
@@ -269,12 +277,12 @@ func reset_progression() -> void:
 # on the same spot.
 var next_building_id: int = 1
 
-# Ships that have been paid for and built but not yet handed to the fleet.
+# Vessels that have been paid for and built but not yet handed to the fleet,
-# Production is simulated here, in the autoload, the same way extractor
+# as a list of VESSEL_* types - a shield vessel finishing while the player is
-# haulers are - so an order can complete while the player is down on a
+# on a planet must not come back as an interceptor. Production is simulated
-# planet's surface, where there is no Fleet node to hand a ship to. The fleet
+# here, in the autoload, the same way extractor haulers are, so an order can
-# claims them when it next can.
+# complete where there is no Fleet node to hand a ship to.
-var ships_owed: int = 0
+var vessels_owed: Array = []
 
 signal order_completed(building_id: int, type: String)
 
@@ -372,6 +380,33 @@ var vessel_levels: Dictionary = {}
 signal vessel_upgraded(upgrade_id: String)
 
 
+func has_ship_lab() -> bool:
+	for b in buildings:
+		if b.type == BUILDING_SHIP_LAB:
+			return true
+	return false
+
+
+func shield_vessel_unlocked() -> bool:
+	# Unlocked AT the lab, by paying for it there - a vessel type rather than
+	# a stat, so it is a one-off rather than a level.
+	return int(vessel_levels.get(UNLOCK_SHIELD_VESSEL, 0)) > 0
+
+
+const UNLOCK_SHIELD_VESSEL: String = "unlock_shield"
+const UNLOCK_SHIELD_COST: int = 45
+
+
+func unlock_shield_vessel() -> bool:
+	if shield_vessel_unlocked() or not has_ship_lab():
+		return false
+	if not spend(UNLOCK_SHIELD_COST):
+		return false
+	vessel_levels[UNLOCK_SHIELD_VESSEL] = 1
+	vessel_upgraded.emit(UNLOCK_SHIELD_VESSEL)
+	return true
+
+
 func upgrade_def(id: String) -> Dictionary:
 	for u in VESSEL_UPGRADES:
 		if u.id == id:
@@ -404,7 +439,7 @@ func upgrade_cost(id: String) -> int:
 
 
 func can_buy_upgrade(id: String) -> bool:
-	return not upgrade_maxed(id) and can_afford(upgrade_cost(id))
+	return has_ship_lab() and not upgrade_maxed(id) and can_afford(upgrade_cost(id))
 
 
 func buy_upgrade(id: String) -> bool:
@@ -531,6 +566,8 @@ func queue_order(id: int, product: String = PRODUCT_SHIP) -> bool:
 	var b: Dictionary = find_building(id)
 	if b.is_empty() or not can_produce(b.type):
 		return false
+	if product == VESSEL_SHIELD and not shield_vessel_unlocked():
+		return false
 	if product == PRODUCT_TRANSPORTER and not has_transport_hub():
 		# Nowhere to station it. Refused rather than queued, so the player is
 		# told now instead of watching an order sit forever.
@@ -570,7 +607,7 @@ func _advance_production() -> void:
 			if product == PRODUCT_TRANSPORTER:
 				_station_transporter(b.position)
 			else:
-				ships_owed += 1
+				vessels_owed.append(product)
 			order_completed.emit(int(b.id), product)
 
 

tests/test_building_stock_queue.gd

@@ -45,7 +45,7 @@ func _initialize() -> void:
 	game_state.extractors.clear()
 	game_state.rocks = 500
 	game_state.fleet_cargo = 0
-	game_state.ships_owed = 0
+	game_state.vessels_owed.clear()
 	# Room to grow: the default cap is BASE_FLEET_SIZE (5) and the fleet
 	# starts at exactly 5, so without this every completed order would have
 	# nowhere to put its vessel and the test would be measuring the cap
@@ -180,7 +180,7 @@ func _process(delta: float) -> bool:
 			# --- 6 + 7. no scene, no fleet: production still completes --
 			# The scene has to be GONE before the order is placed. With a
 			# fleet still alive and under its cap it claims the vessel the
-			# same frame production finishes, which would leave ships_owed
+			# same frame production finishes, which would leave vessels_owed
 			# back at 0 and prove nothing about orders surviving without it.
 			ships_at_start = fleet.ships.size()
 			scene.queue_free()
@@ -207,11 +207,11 @@ func _process(delta: float) -> bool:
 				print("TEST_BUILDING_STOCK_QUEUE: FAIL (order stalled once the space scene was gone)")
 				quit(1)
 				return true
-			if game_state.ships_owed < 1:
+			if game_state.vessels_owed.is_empty():
 				print("TEST_BUILDING_STOCK_QUEUE: FAIL (vessel completed with no fleet present was lost, not owed)")
 				quit(1)
 				return true
-			print("no scene at all -> order completed, %d vessel owed" % game_state.ships_owed)
+			print("no scene at all -> order completed, %d vessel owed" % game_state.vessels_owed.size())
 
 			# Come back to space: the fleet should claim what it is owed.
 			scene = load("res://Main.tscn").instantiate()
@@ -223,8 +223,8 @@ func _process(delta: float) -> bool:
 		8:
 			if elapsed < 0.5:
 				return false
-			if game_state.ships_owed != 0:
+			if not game_state.vessels_owed.is_empty():
-				print("TEST_BUILDING_STOCK_QUEUE: FAIL (returning fleet never claimed its %d owed vessel(s))" % game_state.ships_owed)
+				print("TEST_BUILDING_STOCK_QUEUE: FAIL (returning fleet never claimed its %d owed vessel(s))" % game_state.vessels_owed.size())
 				quit(1)
 				return true
 			print("fleet returned and claimed the owed vessel (ships=%d)" % fleet.ships.size())

tests/test_crafter_feedback.gd

@@ -38,7 +38,7 @@ func _initialize() -> void:
 	game_state.unlocked = ["shipyards", "coordination", "wing"]
 	game_state.rocks = 100
 	game_state.fleet_cargo = 0
-	game_state.ships_owed = 0
+	game_state.vessels_owed.clear()
 	scene = load("res://Main.tscn").instantiate()
 	root.add_child(scene)
 	controller = scene.get_node("BuildController")

tests/test_crafter_feedback.gd.uid

@@ -0,0 +1 @@
+uid://c33061yx51h5s

tests/test_hub_capacity.gd

@@ -34,7 +34,7 @@ func _initialize() -> void:
 	game_state.transporters.clear()
 	game_state.rocks = 900
 	game_state.fleet_cargo = 0
-	game_state.ships_owed = 0
+	game_state.vessels_owed.clear()
 	game_state.unlocked = ["shipyards", "logistics", "freight"]
 	scene = load("res://Main.tscn").instantiate()
 	root.add_child(scene)

tests/test_manual_supply_route.gd

@@ -50,7 +50,7 @@ func _initialize() -> void:
 	game_state.extractors.clear()
 	game_state.rocks = 40
 	game_state.fleet_cargo = 0
-	game_state.ships_owed = 0
+	game_state.vessels_owed.clear()
 	game_state.unlocked = ["shipyards", "coordination", "wing", "squadron", "armada"]
 	scene = load("res://Main.tscn").instantiate()
 	root.add_child(scene)

tests/test_transporter_supply.gd

@@ -56,7 +56,7 @@ func _initialize() -> void:
 	game_state.transporters.clear()
 	game_state.rocks = 200
 	game_state.fleet_cargo = 0
-	game_state.ships_owed = 0
+	game_state.vessels_owed.clear()
 	game_state.unlocked = ["shipyards", "logistics", "freight", "coordination", "wing", "squadron", "armada"]
 	scene = load("res://Main.tscn").instantiate()
 	root.add_child(scene)