text: /*
   * This file is part of FRLayeredNavigationController.
   *
   * Copyright (c) 2012-2015, Johannes Weiß <weiss@tux4u.de>
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *     * Redistributions of source code must retain the above copyright
   *       notice, this list of conditions and the following disclaimer.
   *     * Redistributions in binary form must reproduce the above copyright
   *       notice, this list of conditions and the following disclaimer in the
   *       documentation and/or other materials provided with the distribution.
   *     * The name of the author may not be used to endorse or promote products
   *       derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
   * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  /* Standard Library */
  #import <UIKit/UIKit.h>
  
  /* Local Imports */
  #import "Utils.h"
  
  @class FRLayeredNavigationItem;
  @class FRLayeredNavigationController;
  /**
   * The FRLayeredNavigationControllerDelegate protocol is used by delegates of FRLayeredNavigationController
   * to detect actions such as views starting to move, in the process of moving, and finished moving. This allows
   * apps which have content 'underneath' the layered controller to adjust it appropriately.
   */
  @protocol FRLayeredNavigationControllerDelegate <NSObject>
  @optional
  /**
   * Sent by the layered navigation controller when it is about to begin moving a view controller. This message
   * is only sent if the controller can be moved.
   *
   * @param layeredController The layered controller being interacted with.
   * @param controller The view controller which is about to be moved.
   */
  - (void)layeredNavigationController:(FRLayeredNavigationController*)layeredController
                   willMoveController:(UIViewController*)controller;
  
  /**
   * Sent by the layered navigation controller when it is moving a view controller. This message
   * may be sent multiple times over the course of an interaction, and so any code implemented by
   * the delegate here should be efficient.
   *
   * @param layeredController The layered controller being interacted with.
   * @param controller The view controller which is currently being moved.
   */
  - (void)layeredNavigationController:(FRLayeredNavigationController*)layeredController
                 movingViewController:(UIViewController*)controller;
  
  /**
   * Sent by the layered navigation controller when it has finished moving a view controller.
   *
   * @param layeredController The layered controller being interacted with.
   * @param controller The view controller which has finished moving.
   */
  - (void)layeredNavigationController:(FRLayeredNavigationController*)layeredController
                    didMoveController:(UIViewController*)controller;
  
  @end
  
  typedef enum {
      FRLayeredAnimationDirectionUp = 1,
      FRLayeredAnimationDirectionDown,
      FRLayeredAnimationDirectionLeft,
      FRLayeredAnimationDirectionRight
  } FRLayeredAnimationDirection;
  
  /**
   * The FRLayeredNavigationController class implements a container view controller that manages the navigation
   * of hierarchical content. This class is not intended for subclassing.
   *
   * The API and the usage is very similar to UINavigationController .
   */
  @interface FRLayeredNavigationController : UIViewController<UIGestureRecognizerDelegate>
  
  /**
   * Initializes and returns a newly created layered navigation controller.
   *
   * @param rootViewController The view controller that resides at the bottom of the navigation stack.
   */
  - (id)initWithRootViewController:(UIViewController *)rootViewController;
  
  /**
   * Initializes and returns a newly created layered navigation controller.
   * Does the same as initWithRootViewController: but has the ability to configure some parameters for the
   * root view controller.
   *
   * @param rootViewController The view controller that resides at the bottom of the navigation stack.
   * @param configuration A block object you can use to control some parameters (such as the width) for the root view
   *                      controller. The block's only parameter is an instance of FRLayeredNavigationItem .
   */
  - (id)initWithRootViewController:(UIViewController *)rootViewController
                     configuration:(void (^)(FRLayeredNavigationItem *item))configuration;
  
  /**
   * Pops the top view controller from the navigation stack and updates the display.
   *
   * @param animated Set this value to YES to animate the transition. Pass NO if you are setting up a layered navigation
   *                 controller before its view is displayed.
   */
  - (void)popViewControllerAnimated:(BOOL)animated;
  
  /**
   * Pops the top view controller from the navigation stack and updates the display.
   *
   * @param animated Set this value to YES to animate the transition. Pass NO if you are setting up a layered navigation
   *                 controller before its view is displayed.
   *
   * @param direction Set this value to an FRLayeredAnimationDirection indicating the direction that layer
   *                  will animate off the screen. This parameter is ignored if animated is NO.
   */
  - (void)popViewControllerAnimated:(BOOL)animated direction:(FRLayeredAnimationDirection)direction;
  
  /**
   * Pops all the view controllers on the stack except the root view controller and updates the display.
   *
   * @param animated Set this value to YES to animate the transition. Pass NO if you are setting up a layered navigation
   *                 controller before its view is displayed.
   */
  - (void)popToRootViewControllerAnimated:(BOOL)animated;
  
  /**
   * Pops all the view controllers on the stack except the root view controller and updates the display.
   *
   * @param animated Set this value to YES to animate the transition. Pass NO if you are setting up a layered navigation
   *                 controller before its view is displayed.
   *
   * @param direction Set this value to an FRLayeredAnimationDirection indicating the direction that layers
   *                  will animate off the screen. This parameter is ignored if animated is NO.
   */
  - (void)popToRootViewControllerAnimated:(BOOL)animated direction:(FRLayeredAnimationDirection)direction;
  
  /**
   * Pops view controllers until the specified view controller is at the top of the navigation stack.
   *
   * @param vc The view controller until which to pop.
   * @param animated Set this value to YES to animate the transition. Pass NO if you are setting up a layered navigation
   *                 controller before its view is displayed.
   */
  - (void)popToViewController:(UIViewController *)vc animated:(BOOL)animated;
  
  /**
   * Pops view controllers until the specified view controller is at the top of the navigation stack.
   *
   * @param vc The view controller until which to pop.
   * @param animated Set this value to YES to animate the transition. Pass NO if you are setting up a layered navigation
   *                 controller before its view is displayed.
   * @param direction Set this value to an FRLayeredAnimationDirection indicating the direction that layers
   *                  will animate off the screen. This parameter is ignored if animated is NO.
   */
  - (void)popToViewController:(UIViewController *)vc
                     animated:(BOOL)animated
                    direction:(FRLayeredAnimationDirection)direction;
  
  /**
   * Pushes a view controller onto the stack on top of anchorViewController and updates the display.
   * All view controllers already on top of anchorViewController get popped automatically first.
   *
   * @param viewController The UIViewController to push on the navigation stack.
   * @param anchorViewController The UIViewController on top of which the new view controller should get pushed.
   * @param maxWidth `YES` if viewController is a content view controller and should therefore use all the remaining
   *                 screen width.
   * @param animated Set this value to YES to animate the transition. Pass NO if you are setting up a layered navigation
   *                 controller before its view is displayed.
   */
  - (void)pushViewController:(UIViewController *)viewController
                   inFrontOf:(UIViewController *)anchorViewController
                maximumWidth:(BOOL)maxWidth
                    animated:(BOOL)animated;
  
  /**
   * Pushes a view controller onto the stack on top of anchorViewController and updates the display.
   * All view controllers already on top of anchorViewController get popped automatically first.
   *
   * @param viewController The UIViewController to push on the navigation stack.
   * @param anchorViewController The UIViewController on top of which the new view controller should get pushed.
   * @param maxWidth `YES` if viewController is a content view controller and should therefore use all the remaining
   *                 screen width.
   * @param animated Set this value to YES to animate the transition. Pass NO if you are setting up a layered navigation
   *                 controller before its view is displayed.
   * @param configuration A block object you can use to control some parameters (such as the width) for the new view
   *                      controller. The block's only parameter is a newly created instance of FRLayeredNavigationItem .
   */
  - (void)pushViewController:(UIViewController *)viewController
                   inFrontOf:(UIViewController *)anchorViewController
                maximumWidth:(BOOL)maxWidth
                    animated:(BOOL)animated
               configuration:(void (^)(FRLayeredNavigationItem *item))configuration;
  
  /**
   * Pushes a view controller onto the stack on top of anchorViewController and updates the display.
   * All view controllers already on top of anchorViewController get popped automatically first.
   *
   * @param viewController The UIViewController to push on the navigation stack.
   * @param anchorViewController The UIViewController on top of which the new view controller should get pushed.
   * @param maxWidth `YES` if viewController is a content view controller and should therefore use all the remaining
   *                 screen width.
   * @param animated Set this value to YES to animate the transition. Pass NO if you are setting up a layered navigation
   *                 controller before its view is displayed.
   * @param configuration A block object you can use to control some parameters (such as the width) for the new view
   *                      controller. The block's only parameter is a newly created instance of FRLayeredNavigationItem .
   * @param direction Set this value to an FRLayeredAnimationDirection indicating the direction that layer
   *                  will animate in from on the screen. This parameter is ignored if animated is NO.
   */
  - (void)pushViewController:(UIViewController *)viewController
                   inFrontOf:(UIViewController *)anchorViewController
                maximumWidth:(BOOL)maxWidth
                    animated:(BOOL)animated
               configuration:(void (^)(FRLayeredNavigationItem *item))configuration
                   direction:(FRLayeredAnimationDirection)direction;
  
  /**
   * Compresses all visible view controllers together, so they're all separated by the minimum distance.
   *
   * @param animated Set this value to `YES` to animate any layer movement that occurs as a result of the compacting.
   */
  - (void)compressViewControllers:(BOOL)animated;
  
  /**
   * If user interaction on the layered navigation controller is enabled.
   */
  @property (nonatomic) BOOL userInteractionEnabled;
  
  /**
   * Returns all the UIViewController objects being managed by the FRNavigationController.
   * Note that, unlike a UINavigationController, this is a readonly property.
   */
  @property (nonatomic, readonly) NSArray *viewControllers;
  
  /**
   * Wheater to drop all layers except the root view controller when pulled far enough to the right
   */
  @property (nonatomic) BOOL dropLayersWhenPulledRight;
  
  /**
   * The view controller in the top layer. (read-only)
   */
  @property(nonatomic, readonly) UIViewController *topViewController;
  
  /**
   * The delegate for the controller.
   */
  @property(nonatomic, weak) id<FRLayeredNavigationControllerDelegate> delegate;
  
  @end
  