navigation-stack/Source/NavigationStack.swift

//
//  NavigationStack.swift
//  NavigationStackDemo
//
// Copyright (c) 26/02/16 Ramotion Inc. (http://ramotion.com)
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.


import UIKit

// MARK: NavigationStack

public class NavigationStack: UINavigationController {
  
  @IBInspectable public var overlay: Float = 0.8
  @IBInspectable public var scaleRatio: Float = 14.0
  @IBInspectable public var scaleValue: Float = 0.99
  @IBInspectable public var decelerationRate: CGFloat = UIScrollViewDecelerationRateNormal
  
  @IBInspectable public var bgColor: UIColor = .blackColor()
  
  public var bgView: UIView? = nil
  private var screens = [UIImage]()
  
  weak public var stackDelegate: UINavigationControllerDelegate? // use this instead delegate
  
  public required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    
    delegate = self
  }
}

// MARK: pulbic methods

extension NavigationStack {
  public func showControllers() {
    if screens.count == 0 {
      return
    }
    
    var allScreens = screens
    allScreens.append(view.takeScreenshot())
    let collectioView = CollectionStackViewController(images: allScreens,
      delegate: self,
      overlay: overlay,
      scaleRatio: scaleRatio,
      scaleValue: scaleValue,
      bgColor: bgColor,
      bgView: bgView,
      decelerationRate: decelerationRate)
        
    presentViewController(collectioView, animated: false, completion: nil)
  }
}


// MARK: Additional helpers

extension NavigationStack {
  
  private func popToIndex(index: Int, animated: Bool) {
    let viewController = viewControllers[index]
    popToViewController(viewController, animated: animated)
  }
}


// MARK: UINavigationControllerDelegate

extension NavigationStack: UINavigationControllerDelegate {
  
  public func navigationController(navigationController: UINavigationController,
    willShowViewController viewController: UIViewController,
    animated: Bool) {
      
      stackDelegate?.navigationController?(navigationController, willShowViewController: viewController, animated: animated)
  
      if navigationController.viewControllers.count > screens.count + 1 {
        screens.append(view.takeScreenshot())
      } else
      if navigationController.viewControllers.count == screens.count && screens.count > 0 {
        screens.removeLast()
      }
  }
  
  public func navigationController(navigationController: UINavigationController, didShowViewController viewController: UIViewController, animated: Bool) {
    stackDelegate?.navigationController?(navigationController, didShowViewController: viewController, animated: animated)
  }

//  ???
//  public func navigationControllerSupportedInterfaceOrientations(navigationController: UINavigationController) -> UIInterfaceOrientationMask {
//    return stackDelegate?.navigationControllerSupportedInterfaceOrientations?(navigationController)
//  }
  
//  ???
//  optional public func navigationControllerPreferredInterfaceOrientationForPresentation(navigationController: UINavigationController) -> UIInterfaceOrientation
//  

  public func navigationController(navigationController: UINavigationController, interactionControllerForAnimationController animationController: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
    return stackDelegate?.navigationController?(navigationController, interactionControllerForAnimationController: animationController)
  }

  public func navigationController(navigationController: UINavigationController, animationControllerForOperation operation: UINavigationControllerOperation, fromViewController fromVC: UIViewController, toViewController toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    return stackDelegate?.navigationController?(navigationController, animationControllerForOperation: operation, fromViewController: fromVC, toViewController: toVC)
  }
  
}

extension NavigationStack: CollectionStackViewControllerDelegate {
  func controllerDidSelected(index index: Int) {
    popToIndex(index, animated: false)
    screens.removeRange(index..<screens.count)
  }
}

// MARK: UIView

extension UIView {
  
  func takeScreenshot() -> UIImage {
    
    UIGraphicsBeginImageContextWithOptions(self.bounds.size, false, UIScreen.mainScreen().scale)
    drawViewHierarchyInRect(self.bounds, afterScreenUpdates: true)
    
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    
    return image
  }
}