/*

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

    See LICENSE.txt for this sample’s licensing information

    Abstract:

                PhotosCollectionViewController is a UICollectionViewController subclass that has a reference to the Album.

*/

import UIKit

class PhotosCollectionViewController: UICollectionViewController {

    // MARK: Properties

    var album: Album? {

        didSet {

            collectionView?.reloadData()

        }

    }

    // MARK: UICollectionViewController

    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {

        return album?.photos.count ?? 0

    }

    /**

        The cell that is returned must be retrieved from a call to 

        `dequeueReusableCellWithReuseIdentifier(_:forIndexPath:)`.

    */

    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Photo", for: indexPath) as! PhotoCollectionViewCell

        cell.photo = album?.photos[(indexPath as NSIndexPath).row]

        return cell

    }

}