refactor: replace SQLModel with QueryModel in various models and update query methods

backend/app/db/query_manager.py

@@ -0,0 +1,59 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Any, Generic, TypeVar
+
+from sqlalchemy import false
+from sqlmodel import SQLModel, col
+
+from app.db.queryset import QuerySet, qs
+
+ModelT = TypeVar("ModelT", bound=SQLModel)
+
+
+@dataclass(frozen=True)
+class ModelManager(Generic[ModelT]):
+    model: type[ModelT]
+    id_field: str = "id"
+
+    def all(self) -> QuerySet[ModelT]:
+        return qs(self.model)
+
+    def none(self) -> QuerySet[ModelT]:
+        return qs(self.model).filter(false())
+
+    def filter(self, *criteria: Any) -> QuerySet[ModelT]:
+        return self.all().filter(*criteria)
+
+    def where(self, *criteria: Any) -> QuerySet[ModelT]:
+        return self.filter(*criteria)
+
+    def filter_by(self, **kwargs: Any) -> QuerySet[ModelT]:
+        queryset = self.all()
+        for field_name, value in kwargs.items():
+            queryset = queryset.filter(col(getattr(self.model, field_name)) == value)
+        return queryset
+
+    def by_id(self, obj_id: Any) -> QuerySet[ModelT]:
+        return self.by_field(self.id_field, obj_id)
+
+    def by_ids(self, obj_ids: list[Any] | tuple[Any, ...] | set[Any]) -> QuerySet[ModelT]:
+        return self.by_field_in(self.id_field, obj_ids)
+
+    def by_field(self, field_name: str, value: Any) -> QuerySet[ModelT]:
+        return self.filter(col(getattr(self.model, field_name)) == value)
+
+    def by_field_in(
+        self,
+        field_name: str,
+        values: list[Any] | tuple[Any, ...] | set[Any],
+    ) -> QuerySet[ModelT]:
+        seq = tuple(values)
+        if not seq:
+            return self.none()
+        return self.filter(col(getattr(self.model, field_name)).in_(seq))
+
+
+class ManagerDescriptor(Generic[ModelT]):
+    def __get__(self, instance: object, owner: type[ModelT]) -> ModelManager[ModelT]:
+        return ModelManager(owner)