"""Wechselkurse: Status und Umrechnungs-Vorschau (für das Buchungsformular)."""

from datetime import date

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

from ..database import get_db
from ..deps import get_current_user
from ..models import ExchangeRate, User
from ..schemas import ConversionOut, RateStatus
from ..services import currency

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


@router.get("/status", response_model=list[RateStatus])
def status(db: Session = Depends(get_db), _: User = Depends(get_current_user)):
    out: list[RateStatus] = []
    currencies = [
        row[0] for row in db.query(ExchangeRate.currency).distinct().order_by(ExchangeRate.currency)
    ]
    for ccy in currencies:
        agg = db.query(
            func.count(ExchangeRate.date),
            func.min(ExchangeRate.date),
            func.max(ExchangeRate.date),
        ).filter(ExchangeRate.currency == ccy).one()
        latest = (
            db.query(ExchangeRate)
            .filter(ExchangeRate.currency == ccy)
            .order_by(ExchangeRate.date.desc())
            .first()
        )
        out.append(
            RateStatus(
                currency=ccy,
                count=agg[0] or 0,
                min_date=agg[1],
                max_date=agg[2],
                latest_rate=float(latest.rate_per_eur) if latest else None,
            )
        )
    return out


@router.get("/convert", response_model=ConversionOut)
def convert(
    amount_cents: int,
    from_currency: str,
    to_currency: str,
    on: date | None = None,
    db: Session = Depends(get_db),
    _: User = Depends(get_current_user),
):
    on = on or date.today()
    from_currency = from_currency.upper()
    to_currency = to_currency.upper()
    converted = currency.convert(db, amount_cents, from_currency, to_currency, on)
    # Anzeige-Kurs: EZB-Kurs der Nicht-EUR-Währung (Einheiten je 1 EUR).
    non_eur = to_currency if to_currency != "EUR" else from_currency
    rate = currency.rate_on(db, non_eur, on)
    return ConversionOut(
        amount_cents=amount_cents,
        from_currency=from_currency,
        to_currency=to_currency,
        date=on,
        converted_cents=converted,
        rate=float(rate) if rate is not None else None,
    )