Reload Collection View in a Collection View Cell through delegation - ios

Question

I have a controller (A) with a Collection View that features 2 cell classes. One of them (B) contains another Collection View. After doing some research, I still cannot figure out how to update the cells in (B) from (A) or elsewhere to get what I want.
Issues
(B) does not reload properly when its button is pressed: the cell with whom the button was tied is still visible even though it is deleted from the userFriendRequests array in (A) in its delegate method. As a bonus I get a crash when I scroll to a new cell in (B) stating that "index is out of range" on the line cell.user = userFriendRequests[indexPath.row].
What I Have
Controller (A)
protocol UserFriendRequestsDelegate: class {
func didPressConfirmFriendButton(_ friendId: String?)
}
/...
fileprivate var userFriendRequests = [User]()
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
if userFriendRequests.isEmpty == false {
switch indexPath.section {
case 0:
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: friendRequestCellId, for: indexPath) as! UserFriendRequests
cell.userFriendRequests = userFriendRequests
cell.delegate = self
return cell
case 1:
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! UserFriendCell
let user = users[indexPath.row]
cell.user = user
return cell
default:
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! UserFriendCell
return cell
}
}
/...
extension AddFriendsController: UserFriendRequestsDelegate {
internal func didPressConfirmFriendButton(_ friendId: String?) {
guard let uid = FIRAuth.auth()?.currentUser?.uid, let friendId = friendId else {
return
}
let userRef = FIRDatabase.database().reference().child("users_friends").child(uid).child(friendId)
let friendRef = FIRDatabase.database().reference().child("users_friends").child(friendId).child(uid)
let value = ["status": "friend"]
userRef.updateChildValues(value) { (error, ref) in
if error != nil {
return
}
friendRef.updateChildValues(value, withCompletionBlock: { (error, ref) in
if error != nil {
return
}
self.setUpRequestsStatusesToConfirmed(uid, friendId: friendId)
DispatchQueue.main.async(execute: {
let index = self.currentUserFriendRequests.index(of: friendId)
self.currentUserFriendRequests.remove(at: index!)
for user in self.userFriendRequests {
if user.id == friendId {
self.userFriendRequests.remove(at: self.userFriendRequests.index(of: user)!)
}
}
self.attemptReloadOfCollectionView()
})
})
}
}
PS: self.attemptReloadOfCollectionView() is a func that simply invalidates a timer, sets it to 0.1 sec and then calls reloadData() on (A)'s Collection View.
CollectionViewCell (B)
weak var delegate: UserFriendRequestsDelegate?
var userFriendRequests = [User]()
/...
#objc fileprivate func confirmFriendButtonPressed(_ sender: UIButton) {
delegate?.didPressConfirmFriendButton(friendId)
}
/...
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return userFriendRequests.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: friendRequestCellId, for: indexPath) as! FriendRequestCell
cell.user = userFriendRequests[indexPath.row]
return cell
}
/...
func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
guard let firstName = userFriendRequests[indexPath.row].first_name, let lastName = userFriendRequests[indexPath.row].last_name, let id = userFriendRequests[indexPath.row].id else {
return
}
nameLabel.text = firstName + " " + lastName
friendId = id
confirmButton.addTarget(self, action: #selector(confirmFriendButtonPressed(_:)), for: .touchUpInside)
}
What I want to achieve
Update (B) when a User is removed from the userFriendRequests array in (A), this User being identified by his id passed by (B) through delegation.
Any good soul that might have an idea on how to tackle this issue ?
Thanks in advance for your help !