Gegenstands-Verwaltung (Non-Food) neben Lebensmitteln

Die Kategorie bestimmt die Verwaltungsart (food/object). Gegenstaende:
Menge je Lagerort statt Chargen/MHD, Umlagern (ohne Grund) und Entfernen
mit Pflicht-Grund samt Entnahme-Statistik. Beliebig viele eigene Felder
je Kategorie (vererbt an Unterkategorien), "gekauft bei" ueber eine
verwaltbare Shop-Liste und ein Produktlink. Barcode-Lookup zusaetzlich
ueber Open Products Facts.

Der Lebensmittel-Teil (Chargen/MHD/FEFO) bleibt unveraendert. Umgesetzt in
Backend (FastAPI, +Tests gruen), Web (React) und iOS (SwiftUI).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/app/routers/field_definitions.py

@@ -0,0 +1,143 @@
+"""Verwaltung der selbst definierten Felder je Kategorie."""
+
+import json
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from ..database import get_db
+from ..deps import get_current_user, require_admin
+from ..models import Category, FieldDefinition, FieldType, ProductFieldValue, User
+from ..schemas import FieldDefinitionCreate, FieldDefinitionOut, FieldDefinitionUpdate
+from ..services.fields import options_list, slugify
+
+router = APIRouter(prefix="/field-definitions", tags=["field-definitions"])
+
+
+def to_out(fd: FieldDefinition, inherited: bool = False) -> FieldDefinitionOut:
+    return FieldDefinitionOut(
+        id=fd.id,
+        category_id=fd.category_id,
+        label=fd.label,
+        key=fd.key,
+        field_type=FieldType(fd.field_type),
+        unit=fd.unit,
+        options=options_list(fd),
+        required=fd.required,
+        position=fd.position,
+        is_builtin=fd.is_builtin,
+        inherited=inherited,
+    )
+
+
+def _unique_key(db: Session, category_id: int, label: str, exclude_id: int | None = None) -> str:
+    """Eindeutigen Schlüssel je Kategorie erzeugen (kapazitaet, kapazitaet_2, …)."""
+    basis = slugify(label)
+    kandidat = basis
+    n = 1
+    while True:
+        query = db.query(FieldDefinition).filter(
+            FieldDefinition.category_id == category_id, FieldDefinition.key == kandidat
+        )
+        if exclude_id is not None:
+            query = query.filter(FieldDefinition.id != exclude_id)
+        if query.first() is None:
+            return kandidat
+        n += 1
+        kandidat = f"{basis}_{n}"
+
+
+def _options_json(field_type: FieldType, options: list[str] | None) -> str | None:
+    if field_type != FieldType.select:
+        return None
+    return json.dumps([o.strip() for o in (options or []) if o.strip()])
+
+
+@router.get("", response_model=list[FieldDefinitionOut])
+def list_field_definitions(
+    category_id: int | None = None,
+    db: Session = Depends(get_db),
+    _: User = Depends(get_current_user),
+) -> list[FieldDefinitionOut]:
+    """Felder auflisten – ohne category_id alle, sonst nur die dieser Kategorie."""
+    query = db.query(FieldDefinition)
+    if category_id is not None:
+        query = query.filter(FieldDefinition.category_id == category_id)
+    rows = query.order_by(
+        FieldDefinition.category_id, FieldDefinition.position, FieldDefinition.id
+    ).all()
+    return [to_out(fd) for fd in rows]
+
+
+@router.post("", response_model=FieldDefinitionOut, status_code=status.HTTP_201_CREATED)
+def create_field_definition(
+    payload: FieldDefinitionCreate,
+    db: Session = Depends(get_db),
+    _: User = Depends(require_admin),
+) -> FieldDefinitionOut:
+    if db.get(Category, payload.category_id) is None:
+        raise HTTPException(status.HTTP_404_NOT_FOUND, "Kategorie nicht gefunden")
+    fd = FieldDefinition(
+        category_id=payload.category_id,
+        label=payload.label.strip(),
+        key=_unique_key(db, payload.category_id, payload.label),
+        field_type=payload.field_type.value,
+        unit=(payload.unit or None),
+        options=_options_json(payload.field_type, payload.options),
+        required=bool(payload.required),
+        position=payload.position,
+    )
+    db.add(fd)
+    db.commit()
+    db.refresh(fd)
+    return to_out(fd)
+
+
+@router.patch("/{field_id}", response_model=FieldDefinitionOut)
+def update_field_definition(
+    field_id: int,
+    payload: FieldDefinitionUpdate,
+    db: Session = Depends(get_db),
+    _: User = Depends(require_admin),
+) -> FieldDefinitionOut:
+    fd = db.get(FieldDefinition, field_id)
+    if fd is None:
+        raise HTTPException(status.HTTP_404_NOT_FOUND, "Feld nicht gefunden")
+
+    data = payload.model_dump(exclude_unset=True)
+    if "label" in data and data["label"]:
+        fd.label = data["label"].strip()
+        fd.key = _unique_key(db, fd.category_id, fd.label, exclude_id=fd.id)
+    if "field_type" in data and data["field_type"] is not None:
+        fd.field_type = data["field_type"].value
+    if "unit" in data:
+        fd.unit = data["unit"] or None
+    if "required" in data and data["required"] is not None:
+        fd.required = bool(data["required"])
+    if "position" in data and data["position"] is not None:
+        fd.position = data["position"]
+    # Optionen immer passend zum (ggf. neuen) Typ ablegen.
+    if "options" in data or "field_type" in data:
+        neuer_typ = FieldType(fd.field_type)
+        optionen = data["options"] if "options" in data else options_list(fd)
+        fd.options = _options_json(neuer_typ, optionen)
+    db.commit()
+    db.refresh(fd)
+    return to_out(fd)
+
+
+@router.delete("/{field_id}", status_code=status.HTTP_204_NO_CONTENT)
+def delete_field_definition(
+    field_id: int,
+    db: Session = Depends(get_db),
+    _: User = Depends(require_admin),
+) -> None:
+    """Löscht das Feld samt aller dazu erfassten Werte (ON DELETE CASCADE)."""
+    fd = db.get(FieldDefinition, field_id)
+    if fd is None:
+        raise HTTPException(status.HTTP_404_NOT_FOUND, "Feld nicht gefunden")
+    db.query(ProductFieldValue).filter(
+        ProductFieldValue.field_definition_id == field_id
+    ).delete()
+    db.delete(fd)
+    db.commit()