from dataclasses import dataclass
from functools import lru_cache
import os


def _int_env(name: str, default: int) -> int:
    raw = os.getenv(name)
    if raw is None or raw == "":
        return default
    return int(raw)


@dataclass(frozen=True)
class Settings:
    app_name: str = os.getenv("APP_NAME", "YG Fine-Tune Platform API")
    app_env: str = os.getenv("APP_ENV", "local")
    api_prefix: str = os.getenv("API_PREFIX", "/api")
    log_level: str = os.getenv("LOG_LEVEL", "INFO")
    log_dir: str = os.getenv("LOG_DIR", "./logs")
    log_file_prefix: str = os.getenv("LOG_FILE_PREFIX", "backend")
    log_error_file_prefix: str = os.getenv("LOG_ERROR_FILE_PREFIX", "error")
    log_max_bytes: int = _int_env("LOG_MAX_BYTES", 20 * 1024 * 1024)
    log_retention_days: int = _int_env("LOG_RETENTION_DAYS", 10)


@lru_cache
def get_settings() -> Settings:
    return Settings()