app.py

from fastapi import FastAPI, Request
from fastapi.responses import RedirectResponse, HTMLResponse
from google.oauth2.credentials import Credentials
from fastapi.staticfiles import StaticFiles
from google_manager.constants import SCOPES
from pages.load_page import load_page
import google_auth_oauthlib.flow
from starlette.middleware.sessions import SessionMiddleware
import gradio as gr
from gpt_summary import Ui
from utils import credentials_to_dict

# Create an instance of the FastAPI app
app = FastAPI()

# Add Session middleware to the app
app.add_middleware(SessionMiddleware, secret_key="mysecret")

# Mount the static files directory
app.mount("/assets", StaticFiles(directory="assets"), name="assets")


@app.get("/", response_class=HTMLResponse)
async def home(request: Request):
    # Load the html content of the auth page
    html_content = load_page("./pages/auth_page.html")

    if "credentials" not in request.session:
        return HTMLResponse(content=html_content, status_code=200)

    else:
        return RedirectResponse("/gradio/?__theme=dark")


# Define the endpoint for Google authentication
@app.get("/auth")
async def authorize(request: Request):
    flow = google_auth_oauthlib.flow.Flow.from_client_secrets_file(
        "credentials.json", scopes=SCOPES
    )

    # for dev
    flow.redirect_uri = "http://127.0.0.1:8000/auth_callback"
    # for production
    # flow.redirect_uri = (
    #     request.url.scheme
    #     + "://"
    #     + request.url.hostname
    #     + (":" + str(request.url.port) if request.url.port else "")
    #     + app.url_path_for("auth_callback")
    # )

    authorization_url, state = flow.authorization_url(
        access_type="offline",
        include_granted_scopes="true",
    )
    request.session["state"] = state
    return RedirectResponse(url=authorization_url)


# Define the callback endpoint after successful authentication
@app.get("/auth_callback")
async def auth_callback(request: Request):
    state = request.session["state"]
    flow = google_auth_oauthlib.flow.Flow.from_client_secrets_file(
        "credentials.json", scopes=SCOPES, state=state
    )
    # for dev
    flow.redirect_uri = "http://127.0.0.1:8000/auth_callback"
    # for production
    # flow.redirect_uri = (
    #     request.url.scheme
    #     + "://"
    #     + request.url.hostname
    #     + (":" + str(request.url.port) if request.url.port else "")
    #     + app.url_path_for("auth_callback")
    # )

    # Use the authorization server's response to fetch the OAuth 2.0 tokens.
    authorization_response = str(request.url)
    flow.fetch_token(authorization_response=authorization_response)
    credentials = flow.credentials
    request.session["credentials"] = credentials_to_dict(credentials)
    return RedirectResponse("/gradio?__theme=dark")


# Mount the Gradio UI
app = gr.mount_gradio_app(app, Ui, path="/gradio")