from pydantic_settings import BaseSettings
from functools import lru_cache
import os
from dotenv import load_dotenv

load_dotenv()

class Settings(BaseSettings):
    """
    Lưu trữ và quản lý cấu hình ứng dụng từ biến môi trường.
    Các thuộc tính: facebook_verify_token, facebook_app_secret, ...
    """
    # Facebook Configuration
    facebook_verify_token: str = os.getenv("FACEBOOK_VERIFY_TOKEN") or ""
    facebook_app_secret: str = os.getenv("FACEBOOK_APP_SECRET") or ""
    
    # Google Sheets Configuration
    google_sheets_credentials_file: str = os.getenv("GOOGLE_SHEETS_CREDENTIALS_FILE") or ""
    google_sheets_token_file: str = os.getenv("GOOGLE_SHEETS_TOKEN_FILE") or ""
    conversation_sheet_id: str = os.getenv("CONVERSATION_SHEET_ID") or ""
    
    # Supabase Configuration
    supabase_url: str = os.getenv("SUPABASE_URL") or ""
    supabase_key: str = os.getenv("SUPABASE_KEY") or ""
    
    # Server Configuration
    host: str = os.getenv("HOST", "0.0.0.0") or ""
    port: int = int(os.getenv("PORT", "8000")) or 8000
    
    # Logging Configuration
    log_level: str = os.getenv("LOG_LEVEL", "INFO") or "INFO"

    class Config:
        env_file = ".env"

@lru_cache()
def get_settings() -> Settings:
    """
    Lấy instance Settings đã cache (singleton).
    Input: None
    Output: Settings instance.
    """
    return Settings()