from dataclasses import dataclass
from pathlib import Path
import os

from dotenv import load_dotenv


@dataclass(frozen=True, slots=True)
class Settings:
    port: int
    api_key: str | None
    base_url: str
    model: str
    default_system_prompt: str
    data_dir: Path

    @classmethod
    def from_env(cls) -> "Settings":
        load_dotenv(dotenv_path=Path.cwd() / ".env", override=False)
        return cls(
            port=int(os.getenv("SERVICE_PORT", "8000")),
            api_key=os.getenv("DEEPSEEK_API_KEY"),
            base_url=os.getenv("DEEPSEEK_BASE_URL", "https://api.deepseek.com"),
            model=os.getenv("DEEPSEEK_MODEL", "deepseek-v4-flash"),
            default_system_prompt=os.getenv(
                "DEFAULT_SYSTEM_PROMPT", "You are a helpful assistant."
            ),
            data_dir=Path(os.getenv("CHAT_DATA_DIR", "data")),
        )