MongoDB $graphlookup to link Twitter user account names with user mentions - mongodb

Question

A sample document with user mentions in the tweets dataset I'm working with looks like this. I'm trying to get mongoDB to link the user.screen_name with their mentions in other tweets, if there are any, and go further up the hierarchy if that tweet also mentions someone else.
{
_id: ObjectId("5c8eccb2caa187d17ca6b214"),
text: 'PROMO - Concorra a um Ipad por semana #sorteio Faça seu cadastro e envie seu login para #lepetitpromo RT pls..',
in_reply_to_status_id: null,
retweet_count: null,
contributors: null,
created_at: 'Thu Sep 02 19:30:31 +0000 2010',
geo: null,
source: 'web',
coordinates: null,
in_reply_to_screen_name: null,
truncated: false,
entities: {
user_mentions: [
{
indices: [ 88, 101 ],
screen_name: 'lepetitpromo',
name: 'Le Petit Promo',
id: 116353452
}
],
urls: [],
hashtags: [ { text: 'sorteio', indices: [ 38, 46 ] } ]
},
retweeted: false,
place: null,
user: {
friends_count: 39464,
profile_sidebar_fill_color: 'A32247',
location: 'SP, Brasil',
verified: false,
follow_request_sent: null,
favourites_count: 546,
profile_sidebar_border_color: 'e69cd7',
profile_image_url: 'http://a1.twimg.com/profile_images/1112836301/30480_107192455999355_100001258033161_53885_3288503_n_normal.jpg',
geo_enabled: true,
created_at: 'Mon Feb 22 04:34:35 +0000 2010',
description: 'Promonauta ligada 24hs nas melhores ofertas, sorteios e novidades no TWITTER! - Site http://www.lepetitpromo.com.br - contato: lepetitpromo#gmail.com',
time_zone: 'Brasilia',
url: 'http://lepetitpromo.com.br',
screen_name: 'lepetitpromo',
notifications: null,
profile_background_color: '000000',
listed_count: 683,
lang: 'en',
profile_background_image_url: 'http://a3.twimg.com/profile_background_images/141124445/x5293307ec686ccde4688a7b20c51d5a.jpg',
statuses_count: 49358,
following: null,
profile_text_color: 'b393b3',
protected: false,
show_all_inline_media: false,
profile_background_tile: true,
name: 'Le Petit Promo',
contributors_enabled: false,
profile_link_color: '60a9d1',
followers_count: 57774,
id: 116353452,
profile_use_background_image: true,
utc_offset: -10800
},
favorited: false,
in_reply_to_user_id: null,
id: Long("22824145700")
}
Here's the query I have so far:
db.tweets.aggregate(
[
{
$graphLookup: {
from: 'tweets',
startWith: "$user.screen_name",
connectFromField: 'user.screen_name',
connectToField: 'entities.user_mentions.screen_name',
as: 'User Mentions'
}
}
]
)
But the code above still doesn't return anything, I'm not really sure what I'm getting wrong but any help would be much appreciated.