3rd level nesting lookup rewind at level3 in mongodb - mongodb

Question

I have to add permissions data at each level by getting data(permission object) by permision_id from the permissions collection
at lease one level will contain permission_id and at most 3 levels can have permission_id
Sample Data looks like
{
"name": "label 1",
"permision_id": "1",
"level2": [
{
"name": "label 2.1",
"permision_id": "2",
"level3": [
{
"name": "lebel 3.1",
"permision_id": "8"
},
{
"name": "lebel 3.2",
"permision_id": "6"
}
]
},
{
"name": "label 2.2",
"permision_id": "5"
}
]
}
what I have tried
[
{
'$lookup': {
'from': 'permissions',
'localField': 'permission_id',
'foreignField': '_id',
'as': 'permissions'
}
}, {
'$unwind': {
'path': '$permissions',
'preserveNullAndEmptyArrays': true
}
}, {
'$unwind': {
'path': '$level2',
'preserveNullAndEmptyArrays': true
}
}, {
'$lookup': {
'from': 'permissions',
'let': {
'level2_permission_id': '$level2.permissions_id'
},
'pipeline': [
{
'$match': {
'$expr': {
'$eq': [
'$_id', '$$level2_permission_id'
]
}
}
}
],
'as': 'level2.permissions'
}
}, {
'$unwind': {
'path': '$level2.permissions',
'preserveNullAndEmptyArrays': true
}
}, {
'$unwind': {
'path': '$level2.level3',
'preserveNullAndEmptyArrays': true
}
}, {
'$lookup': {
'from': 'permissions',
'let': {
'level3_permission_id': '$level2.level3.permission_id'
},
'pipeline': [
{
'$match': {
'$expr': {
'$eq': [
'$_id', '$$level3_permission_id'
]
}
}
}
],
'as': 'level2.level3.permissions'
}
}, {
'$unwind': {
'path': '$level2.level3.permissions',
'preserveNullAndEmptyArrays': true
}
},{
'$group': {
'_id': '$_id',
'level2': {
'$push': '$level2'
}
}
}
]
Now the problem is level2 data is pushedd as an array at level1 correctly but I am unable to push level3 data to level2.
Output i got
{
"name": "label 1",
"permision_id": "1",
"permissions": {
"access": true,
"otherPermission": {...}
}
"level2": [
{
"name": "label 2.1",
"permision_id": "2",
"permissions": {
"access": true,
"otherPermission": {...}
}
"level3": {
"permision_id": "8"
"permissions": {
"access": true,
"otherPermission": {...}
}
}
},
{
"name": "label 2.2",
"permision_id": "5"
"permissions": {
"access": true,
"otherPermission": {...}
}
}
]
}
Output Expected at level 2 (level will reamins same)
at level 3 should be array of items with
"level2": [
{
"name": "label 2.1",
"permision_id": "2",
"permissions": {
"access": true,
"otherPermission": {...}
}
"level3": [
{
"name": "lebel 3.1",
"permision_id": "8"
"permissions": {
"access": true,
"otherPermission": {...}
}
},
{
"name": "lebel 3.2",
"permision_id": "6"
"permissions": {
"access": true,
"otherPermission": {...}
}
}
]
},
{
"name": "label 2.2",
"permision_id": "5"
"permissions": {
"access": true,
"otherPermission": {...}
}
}
]