LONDON-IOS/GME Remit/Utilities/CustomUI/SwipeNavigationController.swift

//
//  SwipeNavigationController.swift
//  GME Remit
//
//  Created by InKwon James Kim on 06/09/2019.
//  Copyright © 2019 Gobal Money Express Co. Ltd. All rights reserved.
//

import UIKit

class SwipeNavigationController: UINavigationController {
  
  // MARK: - Lifecycle
  
  override init(rootViewController: UIViewController) {
    super.init(rootViewController: rootViewController)
    delegate = self
  }
  
  override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
    super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
    
    delegate = self
  }
  
  required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    
    delegate = self
  }
  
  override func viewDidLoad() {
    super.viewDidLoad()
    
    // This needs to be in here, not in init
    interactivePopGestureRecognizer?.delegate = self
  }
  
  deinit {
    delegate = nil
    interactivePopGestureRecognizer?.delegate = nil
  }
  
  // MARK: - Overrides
  
  override func pushViewController(_ viewController: UIViewController, animated: Bool) {
    duringPushAnimation = true
    
    super.pushViewController(viewController, animated: animated)
  }
  
  // MARK: - Private Properties
  
  fileprivate var duringPushAnimation = false
  
}

// MARK: - UINavigationControllerDelegate

extension SwipeNavigationController: UINavigationControllerDelegate {
  func navigationController(
    _ navigationController: UINavigationController,
    didShow viewController: UIViewController,
    animated: Bool
) {
    guard let swipeNavigationController = navigationController as? SwipeNavigationController else { return }
    
    swipeNavigationController.duringPushAnimation = false
  }
  
}

// MARK: - UIGestureRecognizerDelegate

extension SwipeNavigationController: UIGestureRecognizerDelegate {
  
  func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
    guard gestureRecognizer == interactivePopGestureRecognizer else {
      return true // default value
    }
    
    // Disable pop gesture in two situations:
    // 1) when the pop animation is in progress
    // 2) when user swipes quickly a couple of times and animations don't have time to be performed
    return viewControllers.count > 1 && duringPushAnimation == false
  }
}