/*

    Copyright (C) 2017 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    A `UICollectionViewCell` subclass that contains a `UICollectionView`. This class demonstrates how to ensure the focus is passed to the contained collection view.

*/

import UIKit

class CollectionViewContainerCell: UICollectionViewCell, UICollectionViewDataSource, UICollectionViewDelegate {

    // MARK: Properties

    static let reuseIdentifier = "CollectionViewContainerCell"

    @IBOutlet var collectionView: UICollectionView!

    private var dataItems = [DataItem]()

    private let cellComposer = DataItemCellComposer()

    override var preferredFocusedView: UIView? {

        return collectionView

    }

    // MARK: Configuration

    func configure(with dataItems: [DataItem]) {

        self.dataItems = dataItems

        collectionView.reloadData()

    }

    // MARK: UICollectionViewDataSource

    func numberOfSections(in collectionView: UICollectionView) -> Int {

        return 1

    }

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

        return dataItems.count

    }

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

        return collectionView.dequeueReusableCell(withReuseIdentifier: DataItemCollectionViewCell.reuseIdentifier, for: indexPath)

    }

    // MARK: UICollectionViewDelegate

    func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {

        guard let cell = cell as? DataItemCollectionViewCell else { fatalError("Expected to display a DataItemCollectionViewCell") }

        let item = dataItems[(indexPath as NSIndexPath).row]

        // Configure the cell.

        cellComposer.compose(cell, withDataItem: item)

    }

}