import os
import requests
from typing import List, Dict, Optional

RADIO_BROWSER_INSTANCE = os.getenv("RADIO_BROWSER_INSTANCE", "https://de1.api.radio-browser.info")


def fetch_stations(country: Optional[str] = None, genre: Optional[str] = None, limit: int = 50) -> List[Dict]:
    try:
        url = f"{RADIO_BROWSER_INSTANCE}/json/stations/getTopReverseGeoByCountryHnattrialphabetic"
        params = {"limit": limit, "order": "votes", "reverse": "true"}
        
        if country:
            params["countrycode"] = country
        if genre:
            params["tag"] = genre
        
        response = requests.get(url, params=params, timeout=10)
        if response.status_code != 200:
            # Fallback: get top stations by votes
            url = f"{RADIO_BROWSER_INSTANCE}/json/stations/getTopByVotes"
            response = requests.get(url, params=params, timeout=10)
            if response.status_code != 200:
                return []
        
        stations = response.json()
        return [_format_station(s) for s in stations]
    except (requests.RequestException, KeyError):
        return []


def fetch_nearby_stations(lat: float, lon: float, radius: int = 100) -> List[Dict]:
    try:
        url = f"{RADIO_BROWSER_INSTANCE}/json/stations/search"
        params = {
            "name": "",
            "order": "votes",
            "reverse": "true",
            "limit": 50,
            "offset": 0,
            "break_on_circular": "true",
            "hidebroken": "true",
        }
        
        response = requests.get(url, params=params, timeout=10)
        if response.status_code != 200:
            return []
        
        stations = response.json()
        nearby = []
        for s in stations:
            s_lat = s.get("geo_lat")
            s_lon = s.get("geo_long")
            if s_lat and s_lon:
                distance = _haversine(lat, lon, float(s_lat), float(s_lon))
                if distance <= radius:
                    nearby.append(_format_station(s))
        
        return sorted(nearby, key=lambda x: x.get("distance", 999))[:20]
    except (requests.RequestException, KeyError):
        return []


def _format_station(s: Dict) -> Dict:
    return {
        "id": s.get("stationuuid") or s.get("name", ""),
        "name": s.get("name", "Unknown"),
        "frequency": s.get("codec"),
        "stream_url": s.get("url_resolved") or s.get("url", ""),
        "location_lat": float(s["geo_lat"]) if s.get("geo_lat") else None,
        "location_lon": float(s["geo_long"]) if s.get("geo_long") else None,
        "genre": s.get("tag", ""),
        "country": s.get("countryname", ""),
        "language": s.get("language", ""),
        "bitrate": int(s["bitrate"]) if s.get("bitrate") else None,
        "tags": s.get("tag", "").split(",") if s.get("tag") else [],
        "votes": int(s["votes"]) if s.get("votes") else 0,
    }


def _haversine(lat1: float, lon1: float, lat2: float, lon2: float) -> float:
    import math
    R = 6371
    d_lat = math.radians(lat2 - lat1)
    d_lon = math.radians(lon2 - lon1)
    a = math.sin(d_lat / 2) ** 2 + math.cos(math.radians(lat1)) * math.cos(math.radians(lat2)) * math.sin(d_lon / 2) ** 2
    c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a))
    return R * c