$addFields where condition - mongodb

Question

I want to add extra field to lookup result but i need a condition here. Every user has a relationship status (local field) and it should be added to lookup result for each user, but It's adding every 'status' to every user.
db.getCollection('relationships').aggregate([
{$match: {
user_id: ObjectId("5d3dbe07ea97db13d5b73195")}
},
{
$lookup:
{
from: 'users',
localField: 'relationship.user_id',
foreignField: '_id',
as: 'userss'
}
},
{
$addFields: {
"userss.status": "$relationship.status"
}
},
])
User Schema
{
"_id" : ObjectId("5d3dbe07ea97db13d5b73195"),
"username" : "dipper",
"email" : "test#test.com"
}
Realtionship Schema
{
"user_id" : ObjectId("5d3dbe07ea97db13d5b73195"),
"relationship" : [
{
"user_id" : ObjectId("5d3dbe17ea97db13d5b73196"),
"status" : 0
},
{
"user_id" : ObjectId("5d3dbe28ea97db13d5b73197"),
"status" : 1
}
]
}
I need a result like:
{
"_id" : ObjectId("5d3dbe07ea97db13d5b73196"),
"username" : "mabel",
"email" : "test#test.com",
"status": 0
}
{
"_id" : ObjectId("5d3dbe07ea97db13d5b73197"),
"username" : "wendy",
"email" : "test#test.com",
"status": 1
}

Answer 1

You need $unwind to get single document per relationship:
db.relationships.aggregate([
{
$match: { user_id: ObjectId("5d3dbe07ea97db13d5b73195") }
},
{
$unwind: "$relationship"
},
{
$lookup: {
from: "users",
localField: "relationship.user_id",
foreignField: "_id",
as: "user"
}
},
{
$unwind: "$user"
},
{
$project: {
_id: "$relationship.user_id",
username: "$user.username",
email: "$user.email",
status: "$relationship.status"
}
}
])