/*

    Copyright (C) 2016 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    The AssetTransitionItem class represets a data object used to pass transition information between view controllers. The AssetTransitioning protocol

                is the contract each view controller involved in the transition must conform to. This protocol gives each view controller the chance to negotiate

                what transition items it can support for a given transition.

*/

import UIKit

import Photos

class AssetTransitionItem: NSObject {

    var initialFrame: CGRect

    var image: UIImage {

        didSet {

            imageView?.image = image

        }

    }

    var indexPath: IndexPath

    var asset: PHAsset

    var targetFrame: CGRect?

    var imageView: UIImageView?

    var touchOffset: CGVector = CGVector.zero

    init(initialFrame: CGRect, image: UIImage, indexPath: IndexPath, asset: PHAsset) {

        self.initialFrame = initialFrame

        self.image = image

        self.indexPath = indexPath

        self.asset = asset

        super.init()

    }

}

protocol AssetTransitioning {

    func itemsForTransition(context: UIViewControllerContextTransitioning) -> Array<AssetTransitionItem>

    func targetFrame(transitionItem: AssetTransitionItem) -> CGRect?

    func willTransition(fromController: UIViewController, toController: UIViewController, items: Array<AssetTransitionItem>)

    func didTransition(fromController: UIViewController, toController: UIViewController, items: Array<AssetTransitionItem>)

}