from datetime import datetime

try:
    from lunar_python import Lunar, Solar
except ImportError:  # pragma: no cover - production image installs the package
    Lunar = None
    Solar = None


class BaziCalculator:
    def calculate(self, payload: dict) -> dict:
        birth_date = payload["birth_date"]
        time_unknown = bool(payload.get("time_unknown"))
        birth_time = payload.get("birth_time") if not time_unknown else "12:00"
        hour, minute = self._parse_time(birth_time or "12:00")
        year, month, day = self._parse_date(birth_date)
        calendar_type = payload.get("calendar_type", "solar")

        if Solar and Lunar:
            if calendar_type == "lunar":
                lunar_month = -month if payload.get("is_leap_month") else month
                lunar = Lunar.fromYmdHms(year, lunar_month, day, hour, minute, 0)
                solar = lunar.getSolar()
            else:
                solar = Solar.fromYmdHms(year, month, day, hour, minute, 0)
                lunar = solar.getLunar()
            eight = lunar.getEightChar()
            return {
                "calendar_type": calendar_type,
                "is_leap_month": bool(payload.get("is_leap_month")),
                "birth_date": birth_date,
                "birth_time": None if time_unknown else f"{hour:02d}:{minute:02d}",
                "time_unknown": time_unknown,
                "birth_place": payload.get("birth_place"),
                "nickname": payload.get("nickname"),
                "gender": payload.get("gender"),
                "solar_date": f"{solar.getYear():04d}-{solar.getMonth():02d}-{solar.getDay():02d}",
                "lunar_date": f"{lunar.getYear()}年{lunar.getMonth()}月{lunar.getDay()}日",
                "pillars": {
                    "year": eight.getYear(),
                    "month": eight.getMonth(),
                    "day": eight.getDay(),
                    "time": eight.getTime() if not time_unknown else "时辰不详",
                },
                "wuxing": {
                    "year": eight.getYearWuXing(),
                    "month": eight.getMonthWuXing(),
                    "day": eight.getDayWuXing(),
                    "time": eight.getTimeWuXing() if not time_unknown else "时辰不详",
                },
                "shi_shen": {
                    "year": eight.getYearShiShenGan(),
                    "month": eight.getMonthShiShenGan(),
                    "day": "日主",
                    "time": eight.getTimeShiShenGan() if not time_unknown else "时辰不详",
                },
                "day_master": eight.getDayGan(),
            }

        return self._fallback_chart(payload, year, month, day, hour, minute, time_unknown)

    def _fallback_chart(self, payload: dict, year: int, month: int, day: int, hour: int, minute: int, time_unknown: bool) -> dict:
        stems = "甲乙丙丁戊己庚辛壬癸"
        branches = "子丑寅卯辰巳午未申酉戌亥"
        seed = year * 372 + month * 31 + day + hour

        def pillar(offset: int) -> str:
            return stems[(seed + offset) % 10] + branches[(seed + offset) % 12]

        return {
            "calendar_type": payload.get("calendar_type", "solar"),
            "is_leap_month": bool(payload.get("is_leap_month")),
            "birth_date": payload["birth_date"],
            "birth_time": None if time_unknown else f"{hour:02d}:{minute:02d}",
            "time_unknown": time_unknown,
            "birth_place": payload.get("birth_place"),
            "nickname": payload.get("nickname"),
            "gender": payload.get("gender"),
            "solar_date": payload["birth_date"],
            "lunar_date": "本地未安装 lunar_python，暂用娱乐排盘",
            "pillars": {
                "year": pillar(0),
                "month": pillar(13),
                "day": pillar(27),
                "time": pillar(41) if not time_unknown else "时辰不详",
            },
            "wuxing": {"year": "参考", "month": "参考", "day": "参考", "time": "参考"},
            "shi_shen": {"year": "参考", "month": "参考", "day": "日主", "time": "参考"},
            "day_master": pillar(27)[0],
        }

    def _parse_date(self, value: str) -> tuple[int, int, int]:
        parsed = datetime.strptime(value, "%Y-%m-%d")
        return parsed.year, parsed.month, parsed.day

    def _parse_time(self, value: str) -> tuple[int, int]:
        parsed = datetime.strptime(value, "%H:%M")
        return parsed.hour, parsed.minute