from __future__ import annotations

import os
from dataclasses import dataclass
from datetime import time
from pathlib import Path
from zoneinfo import ZoneInfo, ZoneInfoNotFoundError


@dataclass(frozen=True, slots=True)
class Settings:
    bot_token: str
    database_path: Path
    timezone: ZoneInfo
    daily_report_time: time
    log_level: str = "INFO"

    @classmethod
    def from_env(cls) -> "Settings":
        token = os.getenv("BOT_TOKEN", "").strip()
        if not token:
            raise RuntimeError("Переменная BOT_TOKEN не задана")

        timezone_name = os.getenv("BOT_TIMEZONE", "Asia/Novosibirsk").strip()
        try:
            timezone = ZoneInfo(timezone_name)
        except ZoneInfoNotFoundError as exc:
            raise RuntimeError(f"Неизвестная таймзона BOT_TIMEZONE: {timezone_name}") from exc

        report_time_raw = os.getenv("DAILY_REPORT_TIME", "21:00").strip()
        try:
            hour, minute = (int(part) for part in report_time_raw.split(":", maxsplit=1))
            report_time = time(hour=hour, minute=minute)
        except (ValueError, TypeError) as exc:
            raise RuntimeError("DAILY_REPORT_TIME должен иметь формат ЧЧ:ММ") from exc

        return cls(
            bot_token=token,
            database_path=Path(os.getenv("DATABASE_PATH", "data/finance.db")),
            timezone=timezone,
            daily_report_time=report_time,
            log_level=os.getenv("LOG_LEVEL", "INFO").upper(),
        )