import os
from dataclasses import dataclass
from functools import lru_cache


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


@dataclass(frozen=True)
class Settings:
    app_name: str = "Iron Gateway"
    debug: bool = False
    api_prefix: str = "/api"
    database_url: str = "sqlite+aiosqlite:///./iron.db"
    upload_temp_dir: str = "./.iron-temp/uploads"
    local_storage_dir: str = "./.iron-storage/local"
    cache_dir: str = "./.iron-cache"
    bootstrap_username: str = "admin"
    bootstrap_password: str = "changeme-iron"
    auth_session_ttl_hours: int = 24 * 7
    job_poll_interval_seconds: float = 2.0
    job_batch_size: int = 10

    @classmethod
    def from_env(cls) -> "Settings":
        return cls(
            app_name=os.getenv("IRON_APP_NAME", cls.app_name),
            debug=_get_bool_env("IRON_DEBUG", cls.debug),
            api_prefix=os.getenv("IRON_API_PREFIX", cls.api_prefix),
            database_url=os.getenv("IRON_DATABASE_URL", cls.database_url),
            upload_temp_dir=os.getenv("IRON_UPLOAD_TEMP_DIR", cls.upload_temp_dir),
            local_storage_dir=os.getenv("IRON_LOCAL_STORAGE_DIR", cls.local_storage_dir),
            cache_dir=os.getenv("IRON_CACHE_DIR", cls.cache_dir),
            bootstrap_username=os.getenv("IRON_BOOTSTRAP_USERNAME", cls.bootstrap_username),
            bootstrap_password=os.getenv("IRON_BOOTSTRAP_PASSWORD", cls.bootstrap_password),
            auth_session_ttl_hours=int(
                os.getenv("IRON_AUTH_SESSION_TTL_HOURS", str(cls.auth_session_ttl_hours))
            ),
            job_poll_interval_seconds=float(
                os.getenv("IRON_JOB_POLL_INTERVAL_SECONDS", str(cls.job_poll_interval_seconds))
            ),
            job_batch_size=int(os.getenv("IRON_JOB_BATCH_SIZE", str(cls.job_batch_size))),
        )


@lru_cache(maxsize=1)
def get_settings() -> Settings:
    return Settings.from_env()