"""Anzeige-/Verhaltens-Einstellungen je Benutzer (Schlüssel-Wert).

Jeder Benutzer hat seine eigenen Einstellungen. Unbekannte Schlüssel werden
ebenfalls gespeichert; die hier bekannten liefern sinnvolle Vorgaben.
"""

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

from ..config import get_settings
from ..database import get_db
from ..deps import get_current_user
from ..models import User, UserSetting
from ..schemas import SettingOut

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

BASE_CURRENCY_KEY = "base_currency"
BUDGET_START_DAY_KEY = "budget_start_day"
LOCALE_KEY = "locale"
THEME_KEY = "theme"
DATE_FORMAT_KEY = "date_format"
# Welche Waehrungen in Auswahlfeldern erscheinen (Komma-getrennt).
# Beschraenkt nur die ANZEIGE: Gueltig bleibt alles, was einen
# EZB-Referenzkurs hat – sonst verloere ein Konto seine Waehrung,
# nur weil sie hier gerade nicht angehakt ist.
ACTIVE_CURRENCIES_KEY = "active_currencies"


def known_defaults() -> dict[str, str]:
    return {
        BASE_CURRENCY_KEY: get_settings().default_base_currency,
        BUDGET_START_DAY_KEY: "1",
        LOCALE_KEY: "de",
        THEME_KEY: "system",
        DATE_FORMAT_KEY: "de",
        ACTIVE_CURRENCIES_KEY: "EUR,CHF,USD",
    }


def get_user_setting(db: Session, user: User, key: str) -> str | None:
    row = db.get(UserSetting, (user.id, key))
    if row is not None and row.value is not None:
        return row.value
    return known_defaults().get(key)


@router.get("", response_model=list[SettingOut])
def list_settings(
    db: Session = Depends(get_db), user: User = Depends(get_current_user)
) -> list[SettingOut]:
    rows = db.query(UserSetting).filter(UserSetting.user_id == user.id).all()
    merged: dict[str, str | None] = dict(known_defaults())
    for r in rows:
        merged[r.key] = r.value
    return [SettingOut(key=k, value=v) for k, v in merged.items()]


@router.put("/{key}", response_model=SettingOut)
def set_setting(
    key: str,
    value: str,
    db: Session = Depends(get_db),
    user: User = Depends(get_current_user),
) -> SettingOut:
    row = db.get(UserSetting, (user.id, key))
    if row is None:
        row = UserSetting(user_id=user.id, key=key, value=value)
        db.add(row)
    else:
        row.value = value
    db.commit()
    return SettingOut(key=key, value=value)