"""気象庁の無料JSON APIから天気予報を取得し、洗濯指数を判定する。"""
import logging
from datetime import datetime, timedelta

import httpx

logger = logging.getLogger(__name__)

JMA_FORECAST_URL = "https://www.jma.go.jp/bosai/forecast/data/forecast/{area_code}.json"


async def fetch_tomorrow_weather(area_code: str, area_name_keyword: str) -> dict:
    """指定エリアの明日の天気予報を取得する。

    area_code: 気象庁の府県予報区コード（例: 千葉県 = 120000）
    area_name_keyword: 府県内の地域区分名の一部（例: 市川市が属する「北西部」）
    """
    async with httpx.AsyncClient(timeout=10.0) as client:
        response = await client.get(JMA_FORECAST_URL.format(area_code=area_code))
        response.raise_for_status()
        data = response.json()

    # data[0] が短期予報（今日・明日・明後日）
    short_term = data[0]
    time_series = short_term["timeSeries"]

    weather_series = time_series[0]
    pop_series = time_series[1] if len(time_series) > 1 else None

    tomorrow_index = _find_tomorrow_index(weather_series["timeDefines"])

    weather_area = _find_area(weather_series["areas"], area_name_keyword)
    weather_text = weather_area["weathers"][tomorrow_index] if weather_area else "不明"

    pop_value = None
    if pop_series:
        pop_tomorrow_index = _find_tomorrow_index(pop_series["timeDefines"])
        pop_area = _find_area(pop_series["areas"], area_name_keyword)
        if pop_area and pop_area.get("pops"):
            pops = pop_area["pops"]
            # pops は3時間ごとの配列のことが多いため、明日に該当する値の最大値を取る
            relevant_pops = [
                int(p) for p, t in zip(pops, pop_series["timeDefines"])
                if _is_same_date(t, pop_series["timeDefines"][pop_tomorrow_index]) and p
            ]
            if relevant_pops:
                pop_value = max(relevant_pops)

    return {
        "weather": weather_text.strip(),
        "pop": pop_value,
    }


def _find_tomorrow_index(time_defines: list[str]) -> int:
    tomorrow = (datetime.now() + timedelta(days=1)).date()
    for i, t in enumerate(time_defines):
        dt = datetime.fromisoformat(t)
        if dt.date() == tomorrow:
            return i
    return min(1, len(time_defines) - 1)


def _is_same_date(t1: str, t2: str) -> bool:
    return datetime.fromisoformat(t1).date() == datetime.fromisoformat(t2).date()


def _find_area(areas: list[dict], keyword: str) -> dict | None:
    for area in areas:
        if keyword in area["area"]["name"]:
            return area
    return areas[0] if areas else None


def judge_laundry(weather: str, pop: int | None) -> tuple[str, str]:
    """天気と降水確率から洗濯指数を判定する。戻り値: (判定, 理由)"""
    is_rainy = "雨" in weather or "雪" in weather

    if is_rainy:
        return "室内干し推奨", f"明日は「{weather}」のため"
    if pop is None:
        return "外干しOK（降水確率不明）", "降水確率データが取得できませんでした"
    if pop <= 30:
        return "外干しOK", f"降水確率{pop}%と低めです"
    if pop <= 50:
        return "室内干し推奨", f"降水確率{pop}%とやや高めです"
    return "室内干し推奨", f"降水確率{pop}%と高いです"