from __future__ import annotations

import os
from dataclasses import dataclass
from pathlib import Path

from dotenv import load_dotenv


@dataclass(frozen=True)
class Settings:
    telegram_bot_token: str
    telegram_channel_id: str
    telegram_proxy_url: str | None
    scheduler_interval_minutes: int
    kwork_category_ids: list[int]
    fl_rss_url: str | None
    keywords_include: list[str]
    keywords_exclude: list[str]
    min_price_amount: int | None
    requests_timeout_seconds: int
    state_file: Path


def load_settings() -> Settings:
    load_dotenv()

    telegram_bot_token = _require_env("TELEGRAM_BOT_TOKEN")
    telegram_channel_id = _require_env("TELEGRAM_CHANNEL_ID")

    return Settings(
        telegram_bot_token=telegram_bot_token,
        telegram_channel_id=telegram_channel_id,
        telegram_proxy_url=_parse_optional_text(os.getenv("TELEGRAM_PROXY_URL", "")),
        scheduler_interval_minutes=int(os.getenv("SCHEDULER_INTERVAL_MINUTES", "5")),
        kwork_category_ids=_parse_int_list(os.getenv("KWORK_CATEGORY_IDS", "41")),
        fl_rss_url=_parse_optional_text(os.getenv("FL_RSS_URL", "https://www.fl.ru/rss/?category=5")),
        keywords_include=_parse_text_list(os.getenv("KEYWORDS_INCLUDE", "")),
        keywords_exclude=_parse_text_list(os.getenv("KEYWORDS_EXCLUDE", "")),
        min_price_amount=_parse_optional_int(os.getenv("MIN_PRICE_AMOUNT", "")),
        requests_timeout_seconds=int(os.getenv("REQUESTS_TIMEOUT_SECONDS", "20")),
        state_file=Path(os.getenv("STATE_FILE", "data/sent_offers.json")),
    )


def _require_env(name: str) -> str:
    value = os.getenv(name)
    if not value:
        raise ValueError(f"Environment variable {name} is required")
    return value


def _parse_text_list(raw_value: str) -> list[str]:
    return [item.strip().lower() for item in raw_value.split(",") if item.strip()]


def _parse_int_list(raw_value: str) -> list[int]:
    return [int(item.strip()) for item in raw_value.split(",") if item.strip()]


def _parse_optional_int(raw_value: str) -> int | None:
    value = raw_value.strip()
    if not value:
        return None
    return int(value)


def _parse_optional_text(raw_value: str) -> str | None:
    value = raw_value.strip()
    if not value:
        return None
    return value