rename lan

src/ezgg_lan_manager/services/AccountingService.py

@@ -0,0 +1,76 @@
+import logging
+from collections.abc import Callable
+from datetime import datetime
+from decimal import Decimal, ROUND_DOWN
+from typing import Optional
+
+from src.ezgg_lan_manager.services.DatabaseService import DatabaseService
+from src.ezgg_lan_manager.types.Transaction import Transaction
+
+logger = logging.getLogger(__name__.split(".")[-1])
+
+
+class InsufficientFundsError(Exception):
+    pass
+
+
+class AccountingService:
+    def __init__(self, db_service: DatabaseService) -> None:
+        self._db_service = db_service
+        self._update_hooks: set[Callable] = set()
+
+    def add_update_hook(self, update_hook: Callable) -> None:
+        """ Adds a function to this service, which is called whenever the account balance changes """
+        self._update_hooks.add(update_hook)
+
+    async def add_balance(self, user_id: int, balance_to_add: Decimal, reference: str) -> Decimal:
+        await self._db_service.add_transaction(Transaction(
+            user_id=user_id,
+            value=balance_to_add,
+            is_debit=False,
+            reference=reference,
+            transaction_date=datetime.now()
+        ))
+        logger.debug(f"Added balance of {self.make_euro_string_from_decimal(balance_to_add)} to user with ID {user_id}")
+        for update_hook in self._update_hooks:
+            await update_hook()
+        return await self.get_balance(user_id)
+
+    async def remove_balance(self, user_id: int, balance_to_remove: Decimal, reference: str) -> Decimal:
+        current_balance = await self.get_balance(user_id)
+        if (current_balance - balance_to_remove) < 0:
+            raise InsufficientFundsError
+        await self._db_service.add_transaction(Transaction(
+            user_id=user_id,
+            value=balance_to_remove,
+            is_debit=True,
+            reference=reference,
+            transaction_date=datetime.now()
+        ))
+        logger.debug(
+            f"Removed balance of {self.make_euro_string_from_decimal(balance_to_remove)} to user with ID {user_id}")
+        for update_hook in self._update_hooks:
+            await update_hook()
+        return await self.get_balance(user_id)
+
+    async def get_balance(self, user_id: int) -> Decimal:
+        balance_buffer = Decimal("0")
+        for transaction in await self._db_service.get_all_transactions_for_user(user_id):
+            if transaction.is_debit:
+                balance_buffer -= transaction.value
+            else:
+                balance_buffer += transaction.value
+        return balance_buffer
+
+    async def get_transaction_history(self, user_id: int) -> list[Transaction]:
+        return await self._db_service.get_all_transactions_for_user(user_id)
+
+    @staticmethod
+    def make_euro_string_from_decimal(euros: Optional[Decimal]) -> str:
+        """
+        Internally, all money values are euros as decimal. Only when showing them to the user we generate a string.
+        """
+        if euros is None:
+            return "0.00 €"
+        rounded_decimal = str(euros.quantize(Decimal(".01"), rounding=ROUND_DOWN))
+        return f"{rounded_decimal} €"