Showing just one image at the time from database (Swift and Firebase) - swift

Question

First of all, I am new in this, so please do not make fun of me :)
Basically, I am trying to show and Image of a product but if the client refuses the product this item will not appear on his account. That is why I am creating another table Rejected (setAcceptedOrRejected) where I put the ID of the product and the Id of the client so I wont see the item he rejected before.
What I tried here it was to get the List (Good) with all the items and the (Bad) with the rejected items. Then compare it to display the picture of the item again.
My problem is that I want to show only 1 picture at the time, if the client refuses then it will show the next one and so on but it wont show that picture again.
I hope you can really help me with this one.
Thank you
func updateImage() {
createListProductsBad ()
var badnot = ""
for bad2 in listProductsBad{
badnot = bad2
}
Database.database().reference().child("Products").child(bad2)queryOrderedByKey().observe(.childAdded, with: { snapshot in
let userInfo = snapshot.value as! NSDictionary
let storageRef = Storage.storage().reference(forURL: profileUrl)
storageRef.downloadURL(completion: { (url, error) in
do {
let data = try Data(contentsOf: url!)
let image = UIImage(data: data as Data)
self.productPhoto.image = image
}
catch _ {
print("error")
}
})
})
}
func setAcceptedOrRejected() {
let notThankyou = [ "ProductID": ProductId,
"UserID": userUID
] as [String : Any]
self.storyboard?.instantiateViewController(withIdentifier: "Home")
self.refProducts.child("Rejected").childByAutoId().setValue(notThankyou)
}
func createListProductsGood () {
Database.database().reference().child("Products").queryOrderedByKey().observe(.childAdded, with: { snapshot in
if !snapshot.exists() { return }
let userInfo = snapshot.value as! NSDictionary
let goodID = String(snapshot.key)
for prod in self.listProductsBad{
if (prod == goodID){
print("Not good **********************")
}else{
if (goodID != "" ){
self.listProductsGood.append(prod)
}
}
}
})
}
func createListProductsBad () {
Database.database().reference().child("Rejected").queryOrderedByKey().observe(.childAdded, with: { snapshot in
let userInfo = snapshot.value as! NSDictionary
let currentID = userInfo["UserID"] as! String
let badProduct = userInfo["ProductID"] as! String
if (self.userUID == currentID ){
self.listProductsBad.append(badProduct)
}
})
}
}

Answer 1

//These can also be swift's dictionaries, [String: AnyObject] or possibility arrays if done correctly. All depends on your style of programming - I prefer NSDictionaries just because.
let availableKeys: NSMutableDictionary = [:]
let rejectedKeys: NSMutableDictionary = [:]
//Might be a better way for you. Depends on what you are looking for.
func sortItems2() -> NSMutableDictionary{
for rejKey in rejectedKeys.allKeys{
//Removes if the rejected key is found in the available ones
availableKeys.remove(rejKey)
}
return availableKeys
}