"""BAN YARO — Nearby Alerts (Giftköder + Vermisste Hunde)"""
from datetime import datetime
from fastapi import APIRouter, Depends

from database import db
from auth import get_current_user_optional as get_optional_user
from math_utils import haversine_m, bbox_deg_from_km

router = APIRouter()

_RADIUS_M = 20_000  # 20 km
_RADIUS_KM = _RADIUS_M / 1000.0


def _bbox(lat: float, lon: float, radius_km: float) -> tuple[float, float, float, float]:
    """Bounding-Box-Approximation für lat/lon innerhalb radius_km."""
    lat_delta, lon_delta = bbox_deg_from_km(lat, radius_km)
    return (lat - lat_delta, lat + lat_delta, lon - lon_delta, lon + lon_delta)


@router.get("")
async def nearby_alerts(lat: float, lon: float, user=Depends(get_optional_user)):
    now = datetime.utcnow().isoformat()
    lat_min, lat_max, lon_min, lon_max = _bbox(lat, lon, _RADIUS_KM)
    with db() as conn:
        # Bounding-Box-Vorfilter per SQL (billig) → reduziert die Kandidaten
        # auf ~10 Einträge statt "alle". Die exakte Haversine-Prüfung passiert
        # anschließend in Python.
        poisons = conn.execute(
            """SELECT lat, lon FROM poison
               WHERE geloest=0 AND expires_at > ?
                 AND lat BETWEEN ? AND ?
                 AND lon BETWEEN ? AND ?""",
            (now, lat_min, lat_max, lon_min, lon_max)
        ).fetchall()
        lost = conn.execute(
            """SELECT lat, lon FROM lost_dogs
               WHERE is_active=1
                 AND lat BETWEEN ? AND ?
                 AND lon BETWEEN ? AND ?""",
            (lat_min, lat_max, lon_min, lon_max)
        ).fetchall()
        # Letzten Standort des Users für geo-basierte Push-Filter speichern
        if user:
            conn.execute(
                """UPDATE push_subscriptions SET last_lat=?, last_lon=?
                   WHERE user_id=?""",
                (lat, lon, user["id"])
            )

    has_poison = any(haversine_m(lat, lon, r["lat"], r["lon"]) <= _RADIUS_M for r in poisons)
    has_lost   = any(haversine_m(lat, lon, r["lat"], r["lon"]) <= _RADIUS_M for r in lost)

    return {"poison": has_poison, "lost": has_lost}