import os
from flask import flash, redirect, url_for
from flask_dance.consumer import oauth_authorized
from flask_dance.consumer.storage.sqla import SQLAlchemyStorage
from flask_dance.contrib.google import make_google_blueprint
from flask_login import current_user, login_user
from sqlalchemy.orm.exc import NoResultFound
from models import db, User, OAuth

# Get Google OAuth credentials from environment variables
GOOGLE_CLIENT_ID = os.environ.get("GOOGLE_CLIENT_ID")
GOOGLE_CLIENT_SECRET = os.environ.get("GOOGLE_CLIENT_SECRET")

# Create the Google OAuth blueprint
google_bp = make_google_blueprint(
    client_id=GOOGLE_CLIENT_ID,
    client_secret=GOOGLE_CLIENT_SECRET,
    scope=["profile", "email"],
    storage=SQLAlchemyStorage(OAuth, db.session, user=current_user)
)

# Register a callback for when the OAuth login is successful
@oauth_authorized.connect_via(google_bp)
def google_logged_in(blueprint, token):
    if not token:
        flash("Failed to log in with Google.", "danger")
        return False

    # Get the user's Google account info
    resp = blueprint.session.get("/oauth2/v1/userinfo")
    if not resp.ok:
        flash("Failed to fetch user info from Google.", "danger")
        return False

    google_info = resp.json()
    google_user_id = str(google_info["id"])
    
    # Find this OAuth token in the database, or create it
    query = OAuth.query.filter_by(
        provider=blueprint.name,
        provider_user_id=google_user_id
    )
    try:
        oauth = query.one()
    except NoResultFound:
        oauth = OAuth(
            provider=blueprint.name,
            provider_user_id=google_user_id,
            token=token
        )

    # Now, check to see if we already have a user with this email
    if oauth.user:
        # If this OAuth token already has an associated user, log them in
        login_user(oauth.user)
        flash("Successfully signed in with Google.", "success")
    else:
        # Check if we have a user with this email already
        user = User.query.filter_by(email=google_info["email"]).first()
        if user:
            # If we do, link the OAuth token to the existing user
            oauth.user = user
            db.session.add(oauth)
            db.session.commit()
            login_user(user)
            flash("Successfully signed in with Google.", "success")
        else:
            # If we don't, create a new user
            username = google_info["email"].split("@")[0]
            # Make sure username is unique
            base_username = username
            count = 1
            while User.query.filter_by(username=username).first():
                username = f"{base_username}{count}"
                count += 1
                
            user = User(
                username=username,
                email=google_info["email"],
                is_oauth_user=True
            )
            # No password is set for OAuth users
            oauth.user = user
            db.session.add_all([user, oauth])
            db.session.commit()
            login_user(user)
            flash("Successfully signed in with Google.", "success")

    # Prevent Flask-Dance from creating another token
    return False