"""Shops / Bezugsquellen: verwaltbare Liste für „gekauft bei“ (nur Gegenstände)."""

from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy import func
from sqlalchemy.orm import Session

from ..database import get_db
from ..deps import get_current_user, require_admin
from ..models import Product, Shop, User
from ..schemas import ShopCreate, ShopOut, ShopUpdate

router = APIRouter(prefix="/shops", tags=["shops"])


def _to_out(db: Session, shop: Shop) -> ShopOut:
    out = ShopOut.model_validate(shop)
    out.product_count = db.query(Product).filter(Product.shop_id == shop.id).count()
    return out


@router.get("", response_model=list[ShopOut])
def list_shops(
    db: Session = Depends(get_db), _: User = Depends(get_current_user)
) -> list[ShopOut]:
    return [_to_out(db, s) for s in db.query(Shop).order_by(Shop.name).all()]


@router.post("", response_model=ShopOut, status_code=status.HTTP_201_CREATED)
def create_shop(
    payload: ShopCreate,
    db: Session = Depends(get_db),
    _: User = Depends(require_admin),
) -> ShopOut:
    name = payload.name.strip()
    if db.query(Shop).filter(func.lower(Shop.name) == name.lower()).first():
        raise HTTPException(status.HTTP_409_CONFLICT, "Diesen Shop gibt es bereits")
    shop = Shop(name=name, website=(payload.website or None))
    db.add(shop)
    db.commit()
    db.refresh(shop)
    return _to_out(db, shop)


@router.patch("/{shop_id}", response_model=ShopOut)
def update_shop(
    shop_id: int,
    payload: ShopUpdate,
    db: Session = Depends(get_db),
    _: User = Depends(require_admin),
) -> ShopOut:
    shop = db.get(Shop, shop_id)
    if shop is None:
        raise HTTPException(status.HTTP_404_NOT_FOUND, "Shop nicht gefunden")

    data = payload.model_dump(exclude_unset=True)
    if "name" in data and data["name"]:
        name = data["name"].strip()
        doppelt = (
            db.query(Shop)
            .filter(func.lower(Shop.name) == name.lower(), Shop.id != shop_id)
            .first()
        )
        if doppelt is not None:
            raise HTTPException(status.HTTP_409_CONFLICT, "Diesen Shop gibt es bereits")
        shop.name = name
    if "website" in data:
        shop.website = data["website"] or None
    db.commit()
    db.refresh(shop)
    return _to_out(db, shop)


@router.delete("/{shop_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_shop(
    shop_id: int,
    db: Session = Depends(get_db),
    _: User = Depends(require_admin),
) -> None:
    """Artikel bleiben bestehen, sie verlieren nur die Bezugsquelle (SET NULL)."""
    shop = db.get(Shop, shop_id)
    if shop is None:
        raise HTTPException(status.HTTP_404_NOT_FOUND, "Shop nicht gefunden")
    # SQLite setzt Fremdschlüssel nicht ohne Weiteres um, deshalb ausdrücklich.
    db.query(Product).filter(Product.shop_id == shop_id).update(
        {Product.shop_id: None}
    )
    db.delete(shop)
    db.commit()