feat: CRUD-API Konten/Buchungen/Kategorien/Regeln

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

finance/app/services/balances.py

@@ -0,0 +1,26 @@
+from decimal import Decimal
+
+from sqlalchemy import func, select
+from sqlalchemy.orm import Session
+
+from app.models.tables import Account, Statement, Transaction
+
+
+def account_balance(session: Session, account: Account) -> Decimal:
+    stmt = session.execute(
+        select(Statement).where(Statement.account_id == account.id,
+                                Statement.status == "confirmed")
+        .order_by(Statement.period_end.desc())).scalars().first()
+    q = select(func.coalesce(func.sum(Transaction.amount), 0)).where(
+        Transaction.account_id == account.id, Transaction.status == "confirmed")
+    if stmt is not None:
+        q = q.where(Transaction.booking_date > stmt.period_end)
+        base = stmt.closing_balance
+    else:
+        base = Decimal("0")
+    return Decimal(base) + Decimal(session.execute(q).scalar_one())
+
+
+def total_balance(session: Session) -> Decimal:
+    accounts = session.execute(select(Account)).scalars().all()
+    return sum((account_balance(session, a) for a in accounts), Decimal("0"))