Add fish selling, buyer profiles, and player wallet

economy/player_wallet.gd

@@ -0,0 +1,45 @@
+class_name PlayerWallet
+extends Node
+
+signal balance_changed(new_balance: int, delta: int)
+
+@export var current_balance: int = 0
+
+
+func _ready() -> void:
+	current_balance = maxi(current_balance, 0)
+
+
+func get_balance() -> int:
+	return current_balance
+
+
+func can_afford(amount: int) -> bool:
+	return amount >= 0 and current_balance >= amount
+
+
+func can_credit(amount: int) -> bool:
+	return (
+		amount >= 0
+		and current_balance <= 9223372036854775807 - amount
+	)
+
+
+func credit(amount: int) -> bool:
+	if not can_credit(amount):
+		return false
+	if amount == 0:
+		return true
+	current_balance += amount
+	balance_changed.emit(current_balance, amount)
+	return true
+
+
+func debit(amount: int) -> bool:
+	if not can_afford(amount):
+		return false
+	if amount == 0:
+		return true
+	current_balance -= amount
+	balance_changed.emit(current_balance, -amount)
+	return true