import time
import math
import datetime
from typing import Dict, Any, Optional
import httpx

# 주요 한국 도시 좌표 목록
KOREAN_CITIES = [
    {"name": "서울", "lat": 37.5665, "lon": 126.9780},
    {"name": "인천", "lat": 37.4563, "lon": 126.7052},
    {"name": "수원", "lat": 37.2636, "lon": 127.0286},
    {"name": "춘천", "lat": 37.8813, "lon": 127.7298},
    {"name": "강릉", "lat": 37.7519, "lon": 128.8761},
    {"name": "대전", "lat": 36.3504, "lon": 127.3845},
    {"name": "세종", "lat": 36.4800, "lon": 127.2890},
    {"name": "청주", "lat": 36.6424, "lon": 127.4890},
    {"name": "대구", "lat": 35.8714, "lon": 128.6014},
    {"name": "포항", "lat": 36.0190, "lon": 129.3435},
    {"name": "전주", "lat": 35.8242, "lon": 127.1480},
    {"name": "광주", "lat": 35.1595, "lon": 126.8526},
    {"name": "부산", "lat": 35.1796, "lon": 129.0756},
    {"name": "울산", "lat": 35.5384, "lon": 129.3114},
    {"name": "창원", "lat": 35.2280, "lon": 128.6811},
    {"name": "제주", "lat": 33.4996, "lon": 126.5312},
]

def find_nearest_city(lat: float, lon: float) -> str:
    closest = min(
        KOREAN_CITIES,
        key=lambda c: (c["lat"] - lat) ** 2 + (c["lon"] - lon) ** 2
    )
    dist_sq = (closest["lat"] - lat) ** 2 + (closest["lon"] - lon) ** 2
    # 약 50km 이내이면 해당 도시명 반환
    if dist_sq < 0.25:
        return closest["name"]
    return "현재 위치"

# WMO Weather interpretation code (WW)
# https://open-meteo.com/en/docs
WMO_MAP = {
    0: ("맑음", "mdi-weather-sunny", "mdi-weather-night", "amber-darken-1", "indigo-lighten-2"),
    1: ("대체로 맑음", "mdi-weather-partly-cloudy", "mdi-weather-night-partly-cloudy", "amber-darken-2", "indigo-lighten-3"),
    2: ("구름 조금", "mdi-weather-partly-cloudy", "mdi-weather-partly-cloudy", "blue-grey-lighten-1", "blue-grey-lighten-1"),
    3: ("흐림", "mdi-weather-cloudy", "mdi-weather-cloudy", "grey-darken-1", "grey-darken-1"),
    45: ("안개", "mdi-weather-fog", "mdi-weather-fog", "blue-grey", "blue-grey"),
    48: ("서리 안개", "mdi-weather-fog", "mdi-weather-fog", "blue-grey", "blue-grey"),
    51: ("약한 이슬비", "mdi-weather-rainy", "mdi-weather-rainy", "light-blue", "light-blue"),
    53: ("이슬비", "mdi-weather-rainy", "mdi-weather-rainy", "light-blue-darken-1", "light-blue-darken-1"),
    55: ("강한 이슬비", "mdi-weather-rainy", "mdi-weather-rainy", "blue-darken-1", "blue-darken-1"),
    56: ("약한 어는 이슬비", "mdi-weather-snowy-rainy", "mdi-weather-snowy-rainy", "cyan", "cyan"),
    57: ("강한 어는 이슬비", "mdi-weather-snowy-rainy", "mdi-weather-snowy-rainy", "cyan-darken-1", "cyan-darken-1"),
    61: ("약한 비", "mdi-weather-rainy", "mdi-weather-rainy", "blue", "blue"),
    63: ("비", "mdi-weather-rainy", "mdi-weather-rainy", "blue-darken-1", "blue-darken-1"),
    65: ("강한 비", "mdi-weather-pouring", "mdi-weather-pouring", "blue-darken-3", "blue-darken-3"),
    66: ("약한 어는 비", "mdi-weather-snowy-rainy", "mdi-weather-snowy-rainy", "cyan", "cyan"),
    67: ("강한 어는 비", "mdi-weather-snowy-rainy", "mdi-weather-snowy-rainy", "cyan-darken-2", "cyan-darken-2"),
    71: ("약한 눈", "mdi-weather-snowy", "mdi-weather-snowy", "light-blue-lighten-3", "light-blue-lighten-3"),
    73: ("눈", "mdi-weather-snowy", "mdi-weather-snowy", "light-blue-lighten-2", "light-blue-lighten-2"),
    75: ("강한 눈", "mdi-weather-snowy-heavy", "mdi-weather-snowy-heavy", "blue-lighten-4", "blue-lighten-4"),
    77: ("싸락눈", "mdi-weather-snowy", "mdi-weather-snowy", "light-blue-lighten-1", "light-blue-lighten-1"),
    80: ("약한 소나기", "mdi-weather-partly-rainy", "mdi-weather-partly-rainy", "blue", "blue"),
    81: ("소나기", "mdi-weather-partly-rainy", "mdi-weather-partly-rainy", "blue-darken-1", "blue-darken-1"),
    82: ("강한 소나기", "mdi-weather-pouring", "mdi-weather-pouring", "blue-darken-2", "blue-darken-2"),
    85: ("약한 눈 소나기", "mdi-weather-snowy", "mdi-weather-snowy", "light-blue", "light-blue"),
    86: ("강한 눈 소나기", "mdi-weather-snowy-heavy", "mdi-weather-snowy-heavy", "blue-lighten-3", "blue-lighten-3"),
    95: ("뇌우", "mdi-weather-lightning", "mdi-weather-lightning", "deep-purple", "deep-purple"),
    96: ("뇌우 및 우박", "mdi-weather-lightning-rainy", "mdi-weather-lightning-rainy", "deep-purple-darken-2", "deep-purple-darken-2"),
    99: ("강한 뇌우 및 우박", "mdi-weather-lightning-rainy", "mdi-weather-lightning-rainy", "deep-purple-darken-3", "deep-purple-darken-3"),
}

def resolve_weather_style(code: int, is_day: int = 1):
    info = WMO_MAP.get(code)
    if not info:
        return {
            "text": "흐림",
            "icon": "mdi-weather-cloudy",
            "color": "grey"
        }
    text, day_icon, night_icon, day_color, night_color = info
    return {
        "text": text,
        "icon": day_icon if is_day else night_icon,
        "color": day_color if is_day else night_color,
    }

# 캐시 저장소: (lat, lon) -> (timestamp, data)
_cache: Dict[str, Any] = {}
CACHE_TTL = 900  # 15분

KOREAN_WEEKDAYS = ["월", "화", "수", "목", "금", "토", "일"]

async def get_weather_forecast(lat: float = 37.5665, lon: float = 126.9780) -> Dict[str, Any]:
    cache_key = f"{round(lat, 2)}_{round(lon, 2)}"
    now = time.time()

    if cache_key in _cache:
        cached_time, cached_data = _cache[cache_key]
        if now - cached_time < CACHE_TTL:
            return cached_data

    url = (
        f"https://api.open-meteo.com/v1/forecast"
        f"?latitude={lat}&longitude={lon}"
        f"&current=temperature_2m,relative_humidity_2m,apparent_temperature,is_day,precipitation,weather_code,wind_speed_10m"
        f"&daily=weather_code,temperature_2m_max,temperature_2m_min,precipitation_probability_max"
        f"&timezone=auto"
    )

    try:
        async with httpx.AsyncClient(timeout=10.0) as client:
            resp = await client.get(url)
            resp.raise_for_status()
            data = resp.json()
    except Exception as e:
        # 캐시가 만료되었더라도 기존 캐시가 있으면 반환
        if cache_key in _cache:
            return _cache[cache_key][1]
        raise e

    current_raw = data.get("current", {})
    daily_raw = data.get("daily", {})

    is_day = current_raw.get("is_day", 1)
    current_code = current_raw.get("weather_code", 0)
    current_style = resolve_weather_style(current_code, is_day)

    current_formatted = {
        "temperature": round(current_raw.get("temperature_2m", 0.0), 1),
        "apparent_temperature": round(current_raw.get("apparent_temperature", 0.0), 1),
        "humidity": current_raw.get("relative_humidity_2m", 0),
        "wind_speed": round(current_raw.get("wind_speed_10m", 0.0), 1),
        "precipitation": current_raw.get("precipitation", 0.0),
        "weather_code": current_code,
        "weather_text": current_style["text"],
        "icon": current_style["icon"],
        "color": current_style["color"],
        "is_day": bool(is_day),
        "time": current_raw.get("time"),
    }

    daily_list = []
    dates = daily_raw.get("time", [])
    weather_codes = daily_raw.get("weather_code", [])
    temps_max = daily_raw.get("temperature_2m_max", [])
    temps_min = daily_raw.get("temperature_2m_min", [])
    precip_probs = daily_raw.get("precipitation_probability_max", [])

    for i in range(len(dates)):
        date_str = dates[i]
        try:
            dt = datetime.date.fromisoformat(date_str)
            weekday_kr = KOREAN_WEEKDAYS[dt.weekday()]
            if i == 0:
                day_label = "오늘"
            elif i == 1:
                day_label = "내일"
            else:
                day_label = f"{weekday_kr}요일"
            formatted_date = f"{dt.month}.{dt.day} ({weekday_kr})"
        except Exception:
            day_label = date_str
            formatted_date = date_str

        code = weather_codes[i] if i < len(weather_codes) else 0
        style = resolve_weather_style(code, 1)

        daily_list.append({
            "date": date_str,
            "day_label": day_label,
            "formatted_date": formatted_date,
            "weather_code": code,
            "weather_text": style["text"],
            "icon": style["icon"],
            "color": style["color"],
            "temp_max": round(temps_max[i], 1) if i < len(temps_max) else 0.0,
            "temp_min": round(temps_min[i], 1) if i < len(temps_min) else 0.0,
            "precipitation_prob": precip_probs[i] if i < len(precip_probs) else 0,
        })

    city_name = find_nearest_city(lat, lon)

    result = {
        "location": {
            "name": city_name,
            "lat": lat,
            "lon": lon,
        },
        "current": current_formatted,
        "daily": daily_list,
        "updated_at": datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    }

    _cache[cache_key] = (now, result)
    return result