Replace CurrencyType with Currency resource

generator/currency_generator.gd

@@ -18,7 +18,7 @@ signal production_tick(amount: BigNumber, cycle_count: int, total_owned: int)
 const HUGE_COST_EXPONENT: int = 1000000
 
 ## Currency target updated by this generator.
-@export var currency: GameState.CurrencyType = GameState.CurrencyType.gold
+@export var currency: Resource = GameState.GOLD_CURRENCY
 ## Data resource containing balancing values and defaults (required).
 @export var data: CurrencyGeneratorData
 ## Enables per-cycle automatic production when true.
@@ -85,6 +85,9 @@ func _ready() -> void:
 	_generator_id = _resolve_generator_id()
 	_ensure_registered()
 	cycle_progress_seconds = 0.0
+	if currency == null:
+		push_warning("CurrencyGenerator '%s' has no currency set; defaulting to Gold." % String(name))
+		currency = GameState.GOLD_CURRENCY
 	if data == null:
 		push_error("CurrencyGenerator '%s' is missing CurrencyGeneratorData." % String(name))
 
@@ -247,40 +250,35 @@ func get_generator_id() -> StringName:
 	_ensure_registered()
 	return _generator_id
 
+## Returns the configured currency id.
+func get_currency_id() -> StringName:
+	return GameState.get_currency_id(currency)
+
 ## True when the generator is both unlocked and available.
 func is_available_to_player() -> bool:
 	return is_unlocked and is_available
 
 ## Routes positive/negative currency deltas to the configured currency bucket.
 func _add_currency(amount: BigNumber) -> void:
-	match currency:
-		GameState.CurrencyType.gold:
-			GameState.add_gold(amount)
-		GameState.CurrencyType.gems:
-			GameState.add_gems(amount)
-		_:
-			push_error("Unknown currency type in CurrencyGenerator._add_currency")
+	if currency == null:
+		push_error("CurrencyGenerator '%s' cannot add currency: currency resource is null." % String(name))
+		return
+
+	GameState.add_currency(currency, amount)
 
 ## Attempts to spend target currency; returns false when insufficient.
 func _spend_currency(cost: BigNumber) -> bool:
-	match currency:
-		GameState.CurrencyType.gold:
-			return GameState.spend_gold(cost)
-		GameState.CurrencyType.gems:
-			return GameState.spend_gems(cost)
-		_:
-			push_error("Unknown currency type in CurrencyGenerator._spend_currency")
-			return false
+	if currency == null:
+		push_error("CurrencyGenerator '%s' cannot spend currency: currency resource is null." % String(name))
+		return false
+
+	return GameState.spend_currency(currency, cost)
 
 ## Returns the current amount for the configured currency type.
 func _get_currency_amount() -> BigNumber:
-	match currency:
-		GameState.CurrencyType.gold:
-			return GameState.gold
-		GameState.CurrencyType.gems:
-			return GameState.gems
-		_:
-			return BigNumber.from_float(0.0)
+	if currency == null:
+		return BigNumber.from_float(0.0)
+	return GameState.get_currency_amount(currency)
 
 ## Safely converts finite float values into BigNumber costs.
 func _float_to_big_number(value: float) -> BigNumber: