chatkit/backend/app/config.py

"""Configuration management for ClassLens backend."""

from __future__ import annotations

import os
from pathlib import Path
from functools import lru_cache

from dotenv import load_dotenv
from pydantic import BaseModel

# Load .env file from the chatkit directory (parent of backend)
env_path = Path(__file__).parent.parent.parent / ".env"
load_dotenv(env_path)


class Settings(BaseModel):
    """Application settings loaded from environment variables."""
    
    # OpenAI
    openai_api_key: str = ""
    
    # Google OAuth
    google_client_id: str = ""
    google_client_secret: str = ""
    google_redirect_uri: str = "http://localhost:8000/auth/callback"
    
    # SendGrid
    sendgrid_api_key: str = ""
    sendgrid_from_email: str = "classlens@example.com"
    
    # Database
    database_url: str = "sqlite+aiosqlite:///./classlens.db"
    
    # Encryption key for tokens (32 bytes, base64 encoded)
    encryption_key: str = ""
    
    # Frontend URL for redirects
    frontend_url: str = "http://localhost:3000"
    
    class Config:
        env_file = ".env"


@lru_cache
def get_settings() -> Settings:
    """Get cached settings instance."""
    return Settings(
        openai_api_key=os.getenv("OPENAI_API_KEY", ""),
        google_client_id=os.getenv("GOOGLE_CLIENT_ID", ""),
        google_client_secret=os.getenv("GOOGLE_CLIENT_SECRET", ""),
        google_redirect_uri=os.getenv("GOOGLE_REDIRECT_URI", "http://localhost:8000/auth/callback"),
        sendgrid_api_key=os.getenv("SENDGRID_API_KEY", ""),
        sendgrid_from_email=os.getenv("SENDGRID_FROM_EMAIL", "classlens@example.com"),
        database_url=os.getenv("DATABASE_URL", "sqlite+aiosqlite:///./classlens.db"),
        encryption_key=os.getenv("ENCRYPTION_KEY", ""),
        frontend_url=os.getenv("FRONTEND_URL", "http://localhost:3000"),
    )


# Google OAuth scopes required for the application
# Note: drive.readonly is sensitive scope; spreadsheets.readonly is less restricted
GOOGLE_SCOPES = [
    "https://www.googleapis.com/auth/spreadsheets.readonly",
    "https://www.googleapis.com/auth/userinfo.email",
    "openid",
]