/*

 Copyright (C) 2018 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 The secondary view controller used for browing the photos.

 */

#import "PhotosViewController.h"

#import "ModelController.h"

#import "DataViewController.h"

@interface PhotosViewController ()

@property (strong, nonatomic) ModelController *modelController;

@property (strong, nonatomic) UIPageViewController *pageViewController;

@end

#pragma mark -

@implementation PhotosViewController

- (void)updateNavBarTitle {

    if (self.modelController.pageData.count > 1) {

        self.title = [NSString stringWithFormat:@"Photos (%zd of %zd)", self.modelController.currentPageIndex + 1, (long)self.modelController.pageData.count];

    }

    else {

        DataViewController *viewController = [self.modelController.pageData objectAtIndex:self.modelController.currentPageIndex];

        self.title = viewController.title;

    }

}

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    // Configure the page view controller and add it as a child view controller.

    _pageViewController =

        [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStylePageCurl

                                        navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal

                                                      options:nil];

    self.pageViewController.delegate = self;

    self.modelController.pageData = self.photosToShow;

    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Storyboard" bundle:nil];

    DataViewController *startingViewController = [self.modelController viewControllerAtIndex:0 storyboard:storyboard];

    NSArray *viewControllers = @[startingViewController];

    [self.pageViewController setViewControllers:viewControllers

                                      direction:UIPageViewControllerNavigationDirectionForward

                                       animated:NO

                                     completion:nil];

    [self updateNavBarTitle];

    self.pageViewController.dataSource = self.modelController;

    [self addChildViewController:self.pageViewController];

    [self.view addSubview:self.pageViewController.view];

    [self.pageViewController didMoveToParentViewController:self];

    _pageAnimationFinished = YES;

}

- (ModelController *)modelController {

    // Return the model controller object, creating it if necessary.

    // In more complex implementations, the model controller may be passed to the view controller.

    if (_modelController == nil) {

        _modelController = [[ModelController alloc] init];

    }

    return _modelController;

}

#pragma mark - UIPageViewControllerDelegate

- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed {

    // update the nav bar title showing which index we are displaying

    [self updateNavBarTitle];

    _pageAnimationFinished = YES;

}

- (UIPageViewControllerSpineLocation)pageViewController:(UIPageViewController *)pageViewController spineLocationForInterfaceOrientation:(UIInterfaceOrientation)orientation {

    // Set the spine position to "min" and the page view controller's view controllers array to contain just one view controller.

    // Setting the spine position to 'UIPageViewControllerSpineLocationMid' in landscape orientation sets the doubleSided property to YES, so set it to NO here.

    UIViewController *currentViewController = self.pageViewController.viewControllers[0];

    NSArray *viewControllers = @[currentViewController];

    [self.pageViewController setViewControllers:viewControllers

                                      direction:UIPageViewControllerNavigationDirectionForward

                                       animated:YES

                                     completion:nil];

    self.pageViewController.doubleSided = NO;

    return UIPageViewControllerSpineLocationMin;

}

- (void)pageViewController:(UIPageViewController *)pageViewController willTransitionToViewControllers:(NSArray *)pendingViewControllers

{

    _pageAnimationFinished = NO;

}

@end