Some more refactoring

AGENTS.md

@@ -71,7 +71,7 @@ Two sources with shared patterns:
 - **comdirect**: `ComdirectGiro`, `ComdirectCreditCard`, `ComdirectDepot`, import to `comdirect_giro` table
 - **unified**: `Transaction`, `TransactionDb` – both ingest pipelines project their staging rows (`import_b4w`, `comdirect_giro`) into one `transactions` table via `src/ingest/transactions.py` (`map_*` mappers + `consolidate_transactions`). Dedup uses a business-key `hash_id` (source + IBAN + value date + amount + text + counterparty) with a UNIQUE constraint and SQLite `INSERT OR IGNORE`, so re-imports are idempotent. Amounts are canonical signed (negative = money out). Depot/credit-card/tagesgeld are not projected yet.
 
-All models inherit from common base in `src/models/_common.py`:
+All models inherit from common base in `src/models/common.py`:
 - `_hash()`: SHA256-based deduplication key
 - `_parse_date_german()`: Handles "07.09.2026" format and values like "offen", "--"
 - `_parse_decimal_german()`: Converts "1,23" to Decimal

alembic/env.py

@@ -6,7 +6,7 @@ from sqlalchemy import engine_from_config, pool
 
 from alembic import context
 from src.db import get_set_engine
-from src.models._common import BaseModelDb
+from src.models.common import BaseModelDb
 
 load_dotenv()  # reads .env into os.environ
 

src/db_utils.py

@@ -1,20 +1,16 @@
-import csv
-from pathlib import Path
 from typing import Any
 
-from sqlalchemy.orm import Session
-
-from src.models._common import BaseModelDb
+from sqlalchemy.orm import DeclarativeBase, Session
 
 
-def _query_existing(
-    session: Session, DbModel: type[BaseModelDb], query_parameters: dict[str, Any]
-) -> BaseModelDb | None:
+def _query_existing[DbModelT: DeclarativeBase](
+    session: Session, DbModel: type[DbModelT], query_parameters: dict[str, Any]
+) -> DbModelT | None:
     query = session.query(DbModel).filter_by(**query_parameters)
     return query.first()
 
 
-def _upsert[DbModelT: BaseModelDb](
+def upsert[DbModelT: DeclarativeBase](
     session: Session,
     DbModel: type[DbModelT],
     parameters_existing: dict[str, Any],
@@ -28,7 +24,6 @@ def _upsert[DbModelT: BaseModelDb](
         if do_update:
             for key, value in parameters_new.items():
                 setattr(existing_db_row, key, value)
-        assert isinstance(existing_db_row, DbModel)
         return existing_db_row
 
     new_db_row = DbModel(**parameters_new)
@@ -37,8 +32,3 @@ def _upsert[DbModelT: BaseModelDb](
     if do_commit:
         session.commit()
     return new_db_row
-
-
-def _reader_raw(path: Path):
-    with path.open() as fid:
-        return list(csv.DictReader(fid))

src/helper/__init__.py

@@ -0,0 +1 @@
+"""Database helper for application-specific persistence operations."""

src/helper/category.py

@@ -0,0 +1,22 @@
+from sqlalchemy.orm import Session
+
+from src.db_utils import upsert
+from src.models.category import Category, CategoryDb
+
+
+def upsert_category(
+    session: Session, category: Category | None, do_commit: bool = True
+) -> CategoryDb | None:
+    if category is None:
+        return None
+
+    parent = upsert_category(session, category.parent, do_commit=False)
+    parameters = {"name": category.name, "parent": parent}
+    return upsert(
+        session,
+        CategoryDb,
+        parameters,
+        parameters,
+        do_update=False,
+        do_commit=do_commit,
+    )

src/ingest/b4w.py

@@ -2,10 +2,11 @@ from pathlib import Path
 
 from sqlalchemy.orm import Session
 
-from src.ingest._common import _reader_raw, _upsert
+from src.db_utils import upsert
+from src.helper.category import upsert_category
+from src.ingest.common import _reader_raw
 from src.ingest.transactions import consolidate_transactions, map_b4w_to_transaction
-from src.models.b4w import B4wDb, B4wExport, Category
-from src.models.category import CategoryDb
+from src.models.b4w import B4wDb, B4wExport
 
 
 def reader_b4w(path: Path) -> list[B4wExport]:
@@ -13,25 +14,6 @@ def reader_b4w(path: Path) -> list[B4wExport]:
     return list(map(B4wExport.model_validate, raw))
 
 
-def upsert_category(
-    session: Session, category: Category | None, do_commit=True
-) -> CategoryDb | None:
-    if category is None:
-        return None
-    parameters = {
-        "name": category.name,
-        "parent": upsert_category(session, category.parent),
-    }
-    return _upsert(
-        session,
-        CategoryDb,
-        parameters,
-        parameters,
-        do_update=False,
-        do_commit=do_commit,
-    )
-
-
 def upsert_b4w(
     session: Session, data: B4wExport, do_update=False, do_commit=True
 ) -> B4wDb | None:
@@ -55,7 +37,7 @@ def upsert_b4w(
         "notes": data.notes,
     }
 
-    return _upsert(
+    return upsert(
         session,
         B4wDb,
         parameters_existing,

src/ingest/comdirect.py

@@ -6,18 +6,18 @@ from typing import cast
 from sqlalchemy.orm import Session
 
 from settings import BANK_ACCOUNTS
-from src.ingest._common import _upsert
+from src.db_utils import upsert
 from src.ingest.transactions import (
     consolidate_transactions,
     map_comdirect_giro_to_transaction,
 )
-from src.models._common import Csv2Dict, CsV2DictMulti
 from src.models.comdirect import (
     ComdirectCreditCard,
     ComdirectDepot,
     ComdirectGiro,
     ComdirectGiroDb,
 )
+from src.models.common import Csv2Dict, CsV2DictMulti
 from src.models.settings import Account, Source
 
 PATTERN_ACCOUNT_NAME = r'^"Umsätze ([^"]+)";"Zeitraum: .*$'
@@ -137,7 +137,7 @@ def upsert_comdirect_giro(
         "text": data.text,
     }
 
-    return _upsert(
+    return upsert(
         session,
         ComdirectGiroDb,
         parameters_existing,

src/ingest/common.py

@@ -0,0 +1,7 @@
+import csv
+from pathlib import Path
+
+
+def _reader_raw(path: Path):
+    with path.open() as fid:
+        return list(csv.DictReader(fid))

src/ingest/transactions.py

@@ -4,9 +4,9 @@ from sqlalchemy import select
 from sqlalchemy.dialects.sqlite import insert as sqlite_insert
 from sqlalchemy.orm import Session
 
-from src.models._common import BaseModelDb
 from src.models.b4w import B4wDb
 from src.models.comdirect import ComdirectGiroDb
+from src.models.common import BaseModelDb
 from src.models.transactions import Transaction, TransactionDb
 
 

src/models/__init__.py

@@ -1,10 +1,43 @@
-from src.models.b4w import B4wExport as B4wExport
-from src.models.category import Category as Category
-from src.models.category_budget import CategoryBudgetDb as CategoryBudgetDb
-from src.models.comdirect import ComdirectCreditCard as ComdirectCreditCard
-from src.models.comdirect import ComdirectDepot as ComdirectDepot
-from src.models.comdirect import ComdirectGiro as ComdirectGiro
-from src.models.settings import Account as Account
-from src.models.settings import Source as Source
-from src.models.transactions import Transaction as Transaction
-from src.models.transactions import TransactionDb as TransactionDb
+from importlib import import_module
+from typing import TYPE_CHECKING, Any
+
+_EXPORTS = {
+    "B4wExport": ".b4w",
+    "Category": ".category",
+    "CategoryBudgetDb": ".category_budget",
+    "ComdirectCreditCard": ".comdirect",
+    "ComdirectDepot": ".comdirect",
+    "ComdirectGiro": ".comdirect",
+    "Account": ".settings",
+    "Source": ".settings",
+    "Transaction": ".transactions",
+    "TransactionDb": ".transactions",
+}
+__all__ = list(_EXPORTS)
+
+
+def __getattr__(name: str) -> Any:
+    module_name = _EXPORTS.get(name)
+    if module_name is None:
+        raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
+
+    value = getattr(import_module(module_name, __name__), name)
+    globals()[name] = value
+    return value
+
+
+def __dir__() -> list[str]:
+    return sorted([*globals(), *__all__])
+
+
+if TYPE_CHECKING:
+    from src.models.b4w import B4wExport as B4wExport
+    from src.models.category import Category as Category
+    from src.models.category_budget import CategoryBudgetDb as CategoryBudgetDb
+    from src.models.comdirect import ComdirectCreditCard as ComdirectCreditCard
+    from src.models.comdirect import ComdirectDepot as ComdirectDepot
+    from src.models.comdirect import ComdirectGiro as ComdirectGiro
+    from src.models.settings import Account as Account
+    from src.models.settings import Source as Source
+    from src.models.transactions import Transaction as Transaction
+    from src.models.transactions import TransactionDb as TransactionDb

src/models/b4w.py

@@ -6,14 +6,14 @@ from sqlalchemy import Date, ForeignKey, Integer, String
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
 from src.constants import IBAN_PATTERN, Currency
-from src.models._common import (
+from src.models.category import Category
+from src.models.common import (
     ExportBaseModel,
     IngestdbBase,
     Sign,
-    _hash,
     date2str,
+    hashify,
 )
-from src.models.category import Category
 
 
 class B4wExport(ExportBaseModel):
@@ -59,7 +59,7 @@ class B4wExport(ExportBaseModel):
     @computed_field  # type: ignore[prop-decorator]
     @property
     def hash_id(self) -> str:
-        return _hash(self.id)
+        return hashify(self.id)
 
     @property
     def amount_signed(self) -> Decimal:

src/models/category.py

@@ -2,7 +2,7 @@ from pydantic import Field, computed_field
 from sqlalchemy import ForeignKey, String, UniqueConstraint
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
-from src.models._common import BaseModelDb, ExportBaseModel, _hash
+from src.models.common import BaseModelDb, ExportBaseModel, hashify
 
 
 class Category(ExportBaseModel):
@@ -12,7 +12,7 @@ class Category(ExportBaseModel):
     @computed_field  # type: ignore[prop-decorator]
     @property
     def hash_id(self) -> str:
-        return _hash(self.name, self.parent)
+        return hashify(self.name, self.parent)
 
     @classmethod
     def from_str(cls, s: str) -> Category | None:

src/models/category_budget.py

@@ -4,7 +4,7 @@ from decimal import Decimal
 from sqlalchemy import Date, ForeignKey, Numeric
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
-from src.models._common import BaseModelDb
+from src.models.common import BaseModelDb
 
 
 class CategoryBudgetDb(BaseModelDb):

src/models/comdirect.py

@@ -5,14 +5,14 @@ from pydantic import ConfigDict, Field, computed_field, field_validator
 from sqlalchemy import Date, String
 from sqlalchemy.orm import Mapped, mapped_column
 
-from src.models._common import (
+from src.models.common import (
     ExportBaseModel,
     IngestdbBase,
-    _hash,
     _parse_date_german,
     _parse_decimal_german,
     date2str,
     decimal2str,
+    hashify,
 )
 
 
@@ -72,7 +72,7 @@ class ComdirectGiro(ComdirectBase):
     @computed_field  # type: ignore[prop-decorator]
     @property
     def hash_id(self) -> str:
-        return _hash(self.date_val, self.date_book, self.text)
+        return hashify(self.date_val, self.date_book, self.text)
 
     @field_validator("date_book", mode="before")
     @classmethod

src/models/common.py

@@ -8,7 +8,7 @@ from sqlalchemy import Date, Numeric, String
 from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column
 
 
-def _hash(*args):
+def hashify(*args):
     raw = "".join(str(args))
     return hashlib.sha256(raw.encode()).hexdigest()
 

src/models/transactions.py

@@ -5,7 +5,7 @@ from pydantic import Field, computed_field
 from sqlalchemy import Date, ForeignKey, Index, Integer, String, UniqueConstraint
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
-from src.models._common import ExportBaseModel, IngestdbBase, _hash, date2str
+from src.models.common import ExportBaseModel, IngestdbBase, date2str, hashify
 
 
 class Transaction(ExportBaseModel):
@@ -33,7 +33,7 @@ class Transaction(ExportBaseModel):
     @computed_field  # type: ignore[prop-decorator]
     @property
     def hash_id(self) -> str:
-        return _hash(
+        return hashify(
             self.source,
             self.account_iban,
             self.date_valid,

tests/test_helper_db.py

@@ -1,7 +1,7 @@
 from sqlalchemy import select
 from sqlalchemy.orm import Session
 
-from src.ingest.b4w import upsert_category
+from src.helper.category import upsert_category
 from src.models import Category
 from src.models.category import CategoryDb