import os
from dataclasses import dataclass


def _require_int(name: str) -> int:
    val = os.environ.get(name)
    if not val:
        raise RuntimeError(f"Env var {name} is required")
    return int(val)


def _require_str(name: str) -> str:
    val = os.environ.get(name)
    if not val:
        raise RuntimeError(f"Env var {name} is required")
    return val


@dataclass(frozen=True)
class Settings:
    api_id: int
    api_hash: str
    phone_number: str
    session_name: str
    sessions_dir: str
    # Цель звонка по умолчанию: @username или numeric user id — прямой p2p звонок.
    call_target: str
    call_ring_timeout: int
    tts_lang: str
    api_token: str | None


def load_settings() -> Settings:
    return Settings(
        api_id=_require_int("API_ID"),
        api_hash=_require_str("API_HASH"),
        phone_number=_require_str("PHONE_NUMBER"),
        session_name=os.environ.get("SESSION_NAME", "caller"),
        sessions_dir=os.environ.get("SESSIONS_DIR", "/data/sessions"),
        call_target=_require_str("CALL_TARGET"),
        call_ring_timeout=int(os.environ.get("CALL_RING_TIMEOUT", "45")),
        tts_lang=os.environ.get("TTS_LANG", "ru"),
        api_token=os.environ.get("API_TOKEN") or None,
    )


settings = load_settings()