"""Live weather for the farm from the free Open-Meteo forecast API (no key). Cached 30 minutes."""
import json
import ssl
import time
import urllib.request
from datetime import datetime

import config

_cache = {"t": 0, "data": None}
URL = ("https://api.open-meteo.com/v1/forecast?latitude={lat}&longitude={lon}"
       "&hourly=et0_fao_evapotranspiration,precipitation,soil_temperature_0cm,shortwave_radiation,wind_speed_10m"
       "&past_days=1&forecast_days=2&timezone=Africa%2FCairo")


def _ssl_context():
    """Use certifi's up-to-date CA bundle when available (old Windows Python installs ship expired CAs)."""
    try:
        import certifi
        return ssl.create_default_context(cafile=certifi.where())
    except ImportError:
        return ssl.create_default_context()


def _fetch():
    with urllib.request.urlopen(URL.format(lat=config.FARM_LAT, lon=config.FARM_LON), timeout=8,
                                context=_ssl_context()) as r:
        return json.load(r)["hourly"]


def current():
    """Return the weather features the irrigation model needs (with safe fallbacks offline)."""
    if time.time() - _cache["t"] > 1800 or _cache["data"] is None:
        try:
            _cache["data"] = _fetch()
            _cache["t"] = time.time()
        except Exception:
            _cache["data"] = None
    h = _cache["data"]
    if not h:
        return {"online": False, "et0_24h": 4.0, "rain_24h": 0.0, "soil_temp": 25.0,
                "radiation": 400.0, "wind": 10.0, "et0_next_24h": 4.0}
    now = datetime.now().strftime("%Y-%m-%dT%H:00")
    i = h["time"].index(now) if now in h["time"] else len(h["time"]) // 2
    past = slice(max(0, i - 23), i + 1)
    nxt = slice(i + 1, i + 25)
    return {
        "online": True,
        "et0_24h": round(sum(v or 0 for v in h["et0_fao_evapotranspiration"][past]), 2),
        "rain_24h": round(sum(v or 0 for v in h["precipitation"][past]), 2),
        "soil_temp": h["soil_temperature_0cm"][i],
        "radiation": h["shortwave_radiation"][i],
        "wind": h["wind_speed_10m"][i],
        "et0_next_24h": round(sum(v or 0 for v in h["et0_fao_evapotranspiration"][nxt]), 2),
        "rain_next_24h": round(sum(v or 0 for v in h["precipitation"][nxt]), 2),
    }