05/31 Phase 2

app/services/account_service.py

@@ -0,0 +1,85 @@
+"""
+Account Service — balance calculated from transactions.
+Balance = sum of income - sum of expenses for an account,
+plus any incoming transfers minus outgoing transfers.
+"""
+
+from decimal import Decimal
+from sqlalchemy import func
+from app.extensions import db
+from app.models.account import Account
+from app.models.transaction import Transaction
+
+
+def calc_balance(account_id):
+    """Recalculate and persist the balance for a given account."""
+    # Income credited to this account
+    income = db.session.query(
+        func.coalesce(func.sum(Transaction.amount), 0)
+    ).filter(
+        Transaction.account_id == account_id,
+        Transaction.transaction_type == 'income'
+    ).scalar()
+
+    # Expenses debited from this account
+    expense = db.session.query(
+        func.coalesce(func.sum(Transaction.amount), 0)
+    ).filter(
+        Transaction.account_id == account_id,
+        Transaction.transaction_type == 'expense'
+    ).scalar()
+
+    # Transfers out (this account is source)
+    transfer_out = db.session.query(
+        func.coalesce(func.sum(Transaction.amount), 0)
+    ).filter(
+        Transaction.account_id == account_id,
+        Transaction.transaction_type == 'transfer'
+    ).scalar()
+
+    # Transfers in (this account is destination)
+    transfer_in = db.session.query(
+        func.coalesce(func.sum(Transaction.amount), 0)
+    ).filter(
+        Transaction.to_account_id == account_id,
+        Transaction.transaction_type == 'transfer'
+    ).scalar()
+
+    balance = Decimal(str(income)) - Decimal(str(expense)) \
+              - Decimal(str(transfer_out)) + Decimal(str(transfer_in))
+
+    account = db.session.get(Account, account_id)
+    if account:
+        account.balance = balance
+        db.session.commit()
+    return balance
+
+
+def recalc_all():
+    """Recalculate balances for all accounts."""
+    for account in Account.query.filter_by(is_active=True).all():
+        calc_balance(account.id)
+
+
+def get_total_assets():
+    """Sum of all positive-balance accounts (non-credit)."""
+    result = db.session.query(
+        func.coalesce(func.sum(Account.balance), 0)
+    ).filter(
+        Account.is_active == True,
+        Account.account_type != 'credit_card',
+        Account.balance > 0
+    ).scalar()
+    return float(result)
+
+
+def get_total_liabilities():
+    """Sum of credit card balances (negative = owed)."""
+    result = db.session.query(
+        func.coalesce(func.sum(Account.balance), 0)
+    ).filter(
+        Account.is_active == True,
+        Account.account_type == 'credit_card',
+        Account.balance < 0
+    ).scalar()
+    return abs(float(result))