import os
from dataclasses import dataclass
from functools import lru_cache
from pathlib import Path

from dotenv import load_dotenv

load_dotenv()


@dataclass(frozen=True)
class AppConfig:
    app_username: str
    app_password: str
    app_password_hash: str | None
    session_secret: str
    database_path: Path
    request_timeout_seconds: int
    session_cookie_secure: bool
    metrics_sampler_interval_seconds: int



def _bool_env(name: str, default: bool) -> bool:
    value = os.getenv(name)
    if value is None:
        return default
    return value.strip().lower() in {"1", "true", "yes", "on"}


@lru_cache(maxsize=1)
def get_config() -> AppConfig:
    data_dir = Path(os.getenv("DATA_DIR", "./data"))
    data_dir.mkdir(parents=True, exist_ok=True)

    return AppConfig(
        app_username=os.getenv("APP_USERNAME", "admin"),
        app_password=os.getenv("APP_PASSWORD", "changeme"),
        app_password_hash=os.getenv("APP_PASSWORD_HASH"),
        session_secret=os.getenv("SESSION_SECRET", "change-this-secret"),
        database_path=Path(os.getenv("DB_PATH", str(data_dir / "dashboard.db"))),
        request_timeout_seconds=int(os.getenv("RPC_TIMEOUT_SECONDS", "15")),
        session_cookie_secure=_bool_env("SESSION_COOKIE_SECURE", False),
        metrics_sampler_interval_seconds=max(15, int(os.getenv("METRICS_SAMPLER_INTERVAL_SECONDS", "60"))),
    )