Firebase: Runing transaction every time I loop through an Array - ios

Question

I'm trying to loop through Array and run transaction to upload each item on Firebase, but am not sure that what i want to do is possible.
The idea is: I have an Array of problems ["problemType1", "problemType2", ... "problemType10"] and I give the user n time to solve it. At the end, I put the solved problems in Array and upload them on Firebase. If the problem exists in the DB, just to update his value.
This way, I want to track what type of problems the player use to resolves easier. At the moment, the code I wrote uploads only one problem. What am I doing wrong?
func uploadTheResolvedProblemsToDB(problems: [String], uid: String) {
let refDB = FIRDatabase.database().reference().child("users").child(uid).child("problems")
for problem in problems {
refDB.runTransactionBlock({ (currentData:FIRMutableData) -> FIRTransactionResult in
var dataToUpdate = currentData.value as? [String : Any]
if dataToUpdate?[problem] == nil {
dataToUpdate = [problem: 0]
var theProblem = dataToUpdate?[problem] as? Int ?? 0
theProblem += 1
dataToUpdate?[problem] = 1
currentData.value = dataToUpdate
return FIRTransactionResult.success(withValue: currentData)
}
else
{
var theProblem = dataToUpdate?[problem] as? Int ?? 0
theProblem += 1
dataToUpdate?[problem] = theProblem
currentData.value = dataToUpdate
return FIRTransactionResult.success(withValue: currentData)
}
}) {(error,commited,snapshot) in
if let error = error {
print("errorrrrr", error.localizedDescription)
}
}
}
}
My Database structure is:
users
I_uid
I_problems
I_problem1: 1
problem2: 1
problem3: 1
Where problems is the child. problem1, problem2, problem3 are the values and 1 is the number of times resolved, each problem was resolved.

Answer 1

I still think the problem's your reference.
func uploadTheResolvedProblemsToDB(problems: [String], uid: String) {
let refDB = FIRDatabase.database().reference().child("users").child(uid).child("problems")
for problem in problems {
refDB.child(problem).runTransactionBlock({ (currentData: FIRMutableData) -> FIRTransactionResult in
var value = currentData.value as? Int
if value == nil {
value = 1
} else {
value += 1
}
currentData.value = value
return FIRTransactionResult.success(withValue: currentData)
}) { (error, comited, snapshot) in
if let error = error {
print("errorrrrr", error.localizedDescription)
}
}
}
}

Answer 2

I have edited your logic a little bit but I believe this is how it should work instead. I have not ran a Firebase instance on this so if there are some discrepancies, its because I cannot fully test it. I hope it helps though:
let refDB = FIRDatabase.database().reference().child("users").child(uid).child("problems")
for problem in problems {
refDB.runTransactionBlock({ (currentData:FIRMutableData) -> FIRTransactionResult in
var dataToUpdate = currentData.value as? [[String : Any]]
if var resultData = dataToUpdate {
if dataToUpdate.keys.contains(problem) {
if let timesResolved = dataToUpdate[problem] as? Int {
resultData[problem] = timesResolved + 1
}
else {
resultData[problem] = 0
}
}
else {
resultData[problem] = 0
}
if !resultData.keys.contains(problem) {
resultData[problem] = dataToUpdate[problem] ?? 0
}
currentData.value = resultData
return FIRTransactionResult.success(withValue: currentData)
}
}) {(error,commited,snapshot) in
if let error = error {
print("errorrrrr", error.localizedDescription)
}
})
}