feat(backend): refactor mono repository

backend/repositories/classification.py

@@ -0,0 +1,101 @@
+# myapp/repositories/classification.py
+# ------------------------------------------------------------
+# Persistence layer for the ``Classification`` lookup table.
+# ------------------------------------------------------------
+
+from __future__ import annotations
+
+from typing import List, Optional
+
+from ..db import BaseRepository
+from ..models import Classification as ClassificationModel
+
+
+class ClassificationRepository(BaseRepository[ClassificationModel]):
+    """
+    Simple CRUD + lookup helpers for the ``Classifications`` table.
+
+    Typical rows look like:
+        ClassificationId | ClassificationName
+        ------------------------------------
+        1                | Baritone
+        2                | Tenor
+        3                | Alto / Mezzo
+        4                | Soprano
+    """
+
+    # ------------------------------------------------------------------
+    # Table‑level constants – change them here if the schema ever changes.
+    # ------------------------------------------------------------------
+    _TABLE = "Classifications"
+    _PK = "ClassificationId"
+
+    # ------------------------------------------------------------------
+    # Basic CRUD operations
+    # ------------------------------------------------------------------
+    def create(self, name: str) -> ClassificationModel:
+        """
+        Insert a new classification row and return the populated model.
+
+        Parameters
+        ----------
+        name: str
+            Human‑readable name (e.g. “Baritone”, “Tenor”, …).
+
+        Returns
+        -------
+        ClassificationModel
+            Instance with the newly assigned ``ClassificationId``.
+        """
+        classification = ClassificationModel(ClassificationId=-1, ClassificationName=name)
+        return self._insert(self._TABLE, classification, self._PK)
+
+    def get_by_id(self, classification_id: int) -> Optional[ClassificationModel]:
+        """
+        Retrieve a single classification by primary key.
+        """
+        sql = f"SELECT * FROM {self._TABLE} WHERE {self._PK} = ?"
+        row = self.db.fetchone(sql, (classification_id,))
+        return ClassificationModel.from_row(row) if row else None
+
+    def find_by_name(self, name: str) -> Optional[ClassificationModel]:
+        """
+        Look up a classification by its exact name.
+        """
+        sql = f"SELECT * FROM {self._TABLE} WHERE ClassificationName = ?"
+        row = self.db.fetchone(sql, (name,))
+        return ClassificationModel.from_row(row) if row else None
+
+    # ------------------------------------------------------------------
+    # Convenience queries
+    # ------------------------------------------------------------------
+    def list_all(self) -> List[ClassificationModel]:
+        """
+        Return every classification row, ordered alphabetically.
+        """
+        sql = f"SELECT * FROM {self._TABLE} ORDER BY ClassificationName ASC"
+        rows = self.db.fetchall(sql)
+        return [ClassificationModel.from_row(r) for r in rows]
+
+    def ensure_exists(self, name: str) -> ClassificationModel:
+        """
+        Idempotent helper used by higher‑level services:
+
+        * If a classification with ``name`` already exists, return it.
+        * Otherwise create a new row and return the freshly inserted model.
+        """
+        existing = self.find_by_name(name)
+        if existing:
+            return existing
+        return self.create(name)
+
+    # ------------------------------------------------------------------
+    # Optional delete (use with care – other tables may have FK constraints)
+    # ------------------------------------------------------------------
+    def delete(self, classification_id: int) -> None:
+        """
+        Hard‑delete a classification row.  In practice you’ll rarely need
+        this because classifications tend to be static reference data.
+        """
+        sql = f"DELETE FROM {self._TABLE} WHERE {self._PK} = ?"
+        self.db.execute(sql, (classification_id,))