SWIFT 4 Detail Disclosure - ios

Question

I'm new to programming and have just started with a deep dive into SWIFT and iOS development.
I've been stuck on a problem for over a few hours now and would be much obliged if someone could answer it. The assignment is bucket list and we have to built a basic app that uses two Table views (one dynamic and one static) to display a list of "bucket list" items using navigator controllers and modal display. In our first assignment, we were allowed to use two segues for the edit and save functionality but in the new assignment, we are being asked to refactor and use one segue with the hint being that we should use sender information. The present code uses two segues as I have not figured out how to refactor. As a note, we are using the accessory Detail Disclosure to bring up list items for edit. This is where I am getting stuck. From what I've been able to read, I understand the Disclosure Detail button is not a "true button" rather it is part of the index path. While I think I understand what needs to be done from a conceptual level, I am having a hell of a time actually solving the problem. Thanks in advance.
import UIKit
class BucketListViewController: UITableViewController,
AddItemTableViewControllerDelegate {
var items = ["awesome","lessawesome","great"]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return items.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "MyCell", for: indexPath)
cell.textLabel?.text = items[indexPath.row]
return cell
}
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print("selected")
}
override func tableView(_ tableView: UITableView, accessoryButtonTappedForRowWith indexPath: IndexPath) {
performSegue(withIdentifier: "EditItemSegue", sender: indexPath)
}
override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
items.remove(at: indexPath.row)
tableView.reloadData()
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "AddItemSegue"{
let navigationController = segue.destination as! UINavigationController
let addItemTableViewController = navigationController.topViewController as! AddItemTableViewController
addItemTableViewController.delegate = self
}else if segue.identifier == "EditItemSegue"{
let navigationController = segue.destination as! UINavigationController
let AddItemTableViewController = navigationController.topViewController as! AddItemTableViewController
AddItemTableViewController.delegate = self
let indexPath = sender as! NSIndexPath
let item = items[indexPath.row]
AddItemTableViewController.item = item
AddItemTableViewController.indexPath = indexPath
}
}
func cancelButtonPressed(by controller: AddItemTableViewController) {
dismiss(animated: true, completion: nil)
}
func itemSaved(by controller: AddItemTableViewController, with text:String, at indexPath: NSIndexPath?) {
if let ip = indexPath {
items[ip.row] = text
}else{
items.append(text)
}
tableView.reloadData()
dismiss(animated: true, completion: nil)
}
}
AddItemTableViewControllerDelegate
import Foundation
import UIKit
protocol AddItemTableViewControllerDelegate: class {
func itemSaved(by controller: AddItemTableViewController, with text:String, at indexPath: NSIndexPath?)
func cancelButtonPressed(by controller: AddItemTableViewController)
}
AddItemTableViewController
import UIKit
class AddItemTableViewController: UITableViewController {
weak var delegate: AddItemTableViewControllerDelegate?
var item: String?
var indexPath: NSIndexPath?
#IBOutlet weak var itemTextField: UITextField!
#IBAction func cancelButtonPressed(_ sender: UIBarButtonItem) {
delegate?.cancelButtonPressed(by: self)
}
#IBAction func saveButtonPressed(_ sender: UIBarButtonItem) {
let text = itemTextField.text!
delegate?.itemSaved(by: self, with: text, at: indexPath)
}
override func viewDidLoad() {
super.viewDidLoad()
itemTextField.text = item
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}