get customer active days from mongodb document - mongodb

Question

I have a mongodb document for customer streaming activations.
[
{
"_id": 1,
"email": "customer1#email.com",
"packageid": "movies",
"command": "activated",
"tid": "123",
"createdAt": ISODate("2021-06-08")
},
{
"_id": 2,
"email": "customer2#email.com",
"packageid": "movies",
"command": "activated",
"tid": "124",
"createdAt": ISODate("2021-06-20")
},
{
"_id": 3,
"email": "customer1#email.com",
"packageid": "movies",
"command": "deactivated",
"tid": "1234",
"createdAt": ISODate("2021-06-10")
},
{
"_id": 4,
"email": "customer2#email.com",
"packageid": "movies",
"command": "deactivated",
"tid": "1244",
"createdAt": ISODate("2021-06-22")
},
{
"_id": 5,
"email": "customer1#email.com",
"packageid": "movies",
"command": "activated",
"tid": "123",
"createdAt": ISODate("2021-06-11")
},
{
"_id": 6,
"email": "customer2#email.com",
"packageid": "movies",
"command": "activated",
"tid": "1244",
"createdAt": ISODate("2021-06-23")
},
{
"_id": 7,
"email": "customer1#email.com",
"packageid": "movies",
"command": "deactivated",
"tid": "1237",
"createdAt": ISODate("2021-06-15")
},
{
"_id": 8,
"email": "customer2#email.com",
"packageid": "movies",
"command": "deactivated",
"tid": "1244",
"createdAt": ISODate("2021-06-25")
},
]
now I wanna group by email and get each customer activated days for specific time frame. let's say 1 month. I've been trying this for few hours
{
"email":"customer1#email.com"
"packageid":"movies",
"days": 3
},
{
"email":"customer1#email.com"
"packageid":"movies",
"days": 5
},
{
"email":"customer2#email.com"
"packageid":"movies",
"days": 3
},
{
"email":"customer2#email.com"
"packageid":"movies",
"days": 3
}
edit: any user can activate then deactivate the service any time they want sometimes users do activate and deactivate multiple times within a same month.
I want to find out how many days customer was activated.

Answer 1

We can use $setWindowFields to compute the $dateDiff and $group the sum.
db.collection.aggregate([
{
"$setWindowFields": {
"partitionBy": {
email: "$email",
packageid: "$packageid"
},
"sortBy": {
"createdAt": 1
},
"output": {
"next": {
$shift: {
output: "$createdAt",
by: 1
}
}
}
}
},
{
$match: {
"command": "activated"
}
},
{
$project: {
email: "$email",
packageid: "$packageid",
"days": {
"$dateDiff": {
startDate: "$createdAt",
endDate: {
$ifNull: [
"$next",
"$$NOW"
]
},
unit: "day"
}
}
}
}
])
Here is the Mongo Playground for your reference.