-------for google config-------

//routes

    // send to google to do the authentication
    app.get('/connect/google', passport.authorize('google', { scope : ['profile', 'email'] }));

    // the callback after google has authorized the user
    app.get('/connect/google/callback',
        passport.authorize('google', {
            successRedirect : '/profile',
            failureRedirect : '/'
        }));
        

    app.get('/unlink/google', isLoggedIn, function(req, res) {
    var user          = req.user;
    user.google.token = undefined;
    user.save(function(err) {
        res.redirect('/profile');
    });
});

//passport

passport.use(new GoogleStrategy({

    clientID        : configAuth.googleAuth.clientID,
    clientSecret    : configAuth.googleAuth.clientSecret,
    callbackURL     : configAuth.googleAuth.callbackURL,
    passReqToCallback : true // allows us to pass in the req from our route (lets us check if a user is logged in or not)

},
function(req, token, refreshToken, profile, done) {

    // asynchronous
    process.nextTick(function() {

        // check if the user is already logged in
        if (!req.user) {

            User.findOne({ 'google.id' : profile.id }, function(err, user) {
                if (err)
                    return done(err);

                if (user) {

                    // if there is a user id already but no token (user was linked at one point and then removed)
                    if (!user.google.token) {
                        user.google.token = token;
                        user.google.name  = profile.displayName;
                        user.google.email = (profile.emails[0].value || '').toLowerCase(); // pull the first email

                        user.save(function(err) {
                            if (err)
                                return done(err);
                                
                            return done(null, user);
                        });
                    }

                    return done(null, user);
                } else {
                    var newUser          = new User();

                    newUser.google.id    = profile.id;
                    newUser.google.token = token;
                    newUser.google.name  = profile.displayName;
                    newUser.google.email = (profile.emails[0].value || '').toLowerCase(); // pull the first email

                    newUser.save(function(err) {
                        if (err)
                            return done(err);
                            
                        return done(null, newUser);
                    });
                }
            });

        } else {
            // user already exists and is logged in, we have to link accounts
            var user               = req.user; // pull the user out of the session

            user.google.id    = profile.id;
            user.google.token = token;
            user.google.name  = profile.displayName;
            user.google.email = (profile.emails[0].value || '').toLowerCase(); // pull the first email

            user.save(function(err) {
                if (err)
                    return done(err);
                    
                return done(null, user);
            });

        }

    });

}));

//auth

'googleAuth' : {
    'clientID'         : 'your-secret-clientID-here',
    'clientSecret'     : 'your-client-secret-here',
    'callbackURL'      : 'http://localhost:8080/auth/google/callback'
}