//
//  SlideAnimatedTransitioning.m
//  SwipeLeft
//
//  Created by Visnu on 4/14/14.
//  Copyright (c) 2014 Visnu Pitiyanuvath. All rights reserved.
//

#import "SlideAnimatedTransitioning.h"

// Tries to duplicate the default iOS 7 slide transition for UINavigationController
@implementation SlideAnimatedTransitioning

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
  UIView *containerView = [transitionContext containerView],
         *fromView = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey].view,
         *toView   = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey].view;

  CGFloat width = containerView.frame.size.width;

  CGRect offsetLeft = fromView.frame; offsetLeft.origin.x = -width/3;

  CGRect offscreenRight = toView.frame; offscreenRight.origin.x = width;
  toView.frame = offscreenRight;
  toView.layer.shadowRadius = 5;
  toView.layer.shadowOpacity = 0.4;

  [containerView addSubview:toView];

  [UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0 options:UIViewAnimationOptionCurveLinear animations:^{
    toView.frame = fromView.frame;

    fromView.frame = offsetLeft;
    fromView.layer.opacity = 0.9;
  } completion:^(BOOL finished) {
    fromView.layer.opacity = 1;
    toView.layer.shadowOpacity = 0;
    // when cancelling or completing the animation, ios simulator seems to sometimes flash black backgrounds during the animation. on devices, this doesn't seem to happen though.
    // containerView.backgroundColor = [UIColor whiteColor];
    [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
  }];
}

- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext
{
  return 0.2;
}

@end