certain/backend/app/routers/bank.py

"""Bankkonten über PSD2 verbinden und abrufen."""

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

from ..database import get_db
from ..deps import get_current_user, get_owned
from ..models import Account, BankAccountLink, BankApp, BankConnection, User
from ..schemas import (
    BankAccountLinkOut,
    BankAppIn,
    BankAppOut,
    BankConnectionOut,
    BankConnectStart,
)
from ..services import bank_sync, geheimnis
from ..services.bank_api import BankFehler

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


def _fehler(e: BankFehler) -> HTTPException:
    return HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(e))


# --- Die Anwendung dieser Installation ---------------------------------------


@router.get("/app", response_model=BankAppOut | None)
def get_app(db: Session = Depends(get_db), user: User = Depends(get_current_user)):
    return db.query(BankApp).filter(BankApp.owner_id == user.id).first()


@router.put("/app", response_model=BankAppOut)
def set_app(payload: BankAppIn, db: Session = Depends(get_db),
            user: User = Depends(get_current_user)):
    """Application ID, Schlüsseldatei und Rückleitungs-Adresse hinterlegen."""
    app = db.query(BankApp).filter(BankApp.owner_id == user.id).first()
    if app is None:
        app = BankApp(owner_id=user.id)
        db.add(app)
    app.application_id = payload.application_id.strip()
    app.private_key_enc = geheimnis.verschluesseln(payload.private_key)
    app.base_url = payload.base_url
    db.commit()
    db.refresh(app)
    return app


@router.delete("/app", status_code=status.HTTP_204_NO_CONTENT)
def delete_app(db: Session = Depends(get_db), user: User = Depends(get_current_user)):
    app = db.query(BankApp).filter(BankApp.owner_id == user.id).first()
    if app is not None:
        db.delete(app)
        db.commit()


@router.get("/banks")
def list_banks(country: str | None = None, search: str | None = None,
               db: Session = Depends(get_db),
               user: User = Depends(get_current_user)) -> dict:
    """Banken suchen – in einem Land oder über alle hinweg.

    Ohne ``country`` wird überall gesucht. Das braucht es, weil die IBAN nicht
    verrät, wo eine Bank sitzt: Revolut vergibt deutsche IBANs aus Litauen.
    """
    if not country and not search:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Bitte ein Land wählen oder einen Suchbegriff eingeben.",
        )
    try:
        return bank_sync.banken(db, user, country, search)
    except BankFehler as e:
        raise _fehler(e) from e


# --- Verbindungen ------------------------------------------------------------


@router.get("/connections", response_model=list[BankConnectionOut])
def list_connections(db: Session = Depends(get_db), user: User = Depends(get_current_user)):
    verbindungen = (
        db.query(BankConnection)
        .filter(BankConnection.owner_id == user.id, BankConnection.session_id.isnot(None))
        .order_by(BankConnection.id)
        .all()
    )
    out = []
    for v in verbindungen:
        eintrag = BankConnectionOut.model_validate(v)
        eintrag.expires_soon = bank_sync.laeuft_bald_ab(v)
        out.append(eintrag)
    return out


@router.post("/connect")
def connect(payload: BankConnectStart, db: Session = Depends(get_db),
            user: User = Depends(get_current_user)) -> dict:
    """Autorisierung starten. Die Antwort enthält die Adresse der Bank."""
    try:
        return bank_sync.starte_verbindung(
            db, user, payload.aspsp_name, payload.country, payload.psu_type)
    except BankFehler as e:
        raise _fehler(e) from e


@router.post("/callback")
def callback(state: str, code: str, db: Session = Depends(get_db),
             user: User = Depends(get_current_user)) -> dict:
    """Der Code von der Rückleitung wird zur Sitzung samt Kontoliste."""
    try:
        return bank_sync.schliesse_verbindung(db, user, state, code)
    except BankFehler as e:
        raise _fehler(e) from e


@router.post("/connections/{connection_id}/sync")
def sync(connection_id: int, db: Session = Depends(get_db),
         user: User = Depends(get_current_user)) -> dict:
    verbindung = get_owned(db, BankConnection, connection_id, user)
    try:
        return bank_sync.hole_umsaetze(db, user, verbindung)
    except BankFehler as e:
        verbindung.last_error = str(e)[:500]
        db.commit()
        raise _fehler(e) from e


@router.delete("/connections/{connection_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_connection(connection_id: int, db: Session = Depends(get_db),
                      user: User = Depends(get_current_user)):
    db.delete(get_owned(db, BankConnection, connection_id, user))
    db.commit()


# --- Kontozuordnung ----------------------------------------------------------


@router.get("/links", response_model=list[BankAccountLinkOut])
def list_links(db: Session = Depends(get_db), user: User = Depends(get_current_user)):
    return (
        db.query(BankAccountLink)
        .filter(BankAccountLink.owner_id == user.id)
        .order_by(BankAccountLink.id)
        .all()
    )


@router.post("/links/{link_id}/account/{account_id}", response_model=BankAccountLinkOut)
def set_link_account(link_id: int, account_id: int, db: Session = Depends(get_db),
                     user: User = Depends(get_current_user)):
    """Ein Bankkonto einem Konto in Certain zuordnen.

    Ohne Zuordnung wird nichts abgerufen – Certain rät nicht, wohin fremde
    Umsätze gehören.
    """
    verknuepfung = get_owned(db, BankAccountLink, link_id, user)
    konto = get_owned(db, Account, account_id, user)
    if konto.currency.upper() != verknuepfung.currency.upper():
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=(f"Währungen passen nicht: Das Bankkonto führt "
                    f"{verknuepfung.currency}, das Konto '{konto.name}' führt "
                    f"{konto.currency}."),
        )
    verknuepfung.account_id = konto.id
    db.commit()
    db.refresh(verknuepfung)
    return verknuepfung


@router.delete("/links/{link_id}/account", response_model=BankAccountLinkOut)
def clear_link_account(link_id: int, db: Session = Depends(get_db),
                       user: User = Depends(get_current_user)):
    verknuepfung = get_owned(db, BankAccountLink, link_id, user)
    verknuepfung.account_id = None
    db.commit()
    db.refresh(verknuepfung)
    return verknuepfung