vlc-ios/Sources/MediaViewController+DataSourceDelegate.swift

/*****************************************************************************
 * MediaViewController+DataSourceDelegate.swift
 * VLC for iOS
 *****************************************************************************
 * Copyright (c) 2018 VideoLAN. All rights reserved.
 * $Id$
 *
 * Authors: Carola Nitz <nitz.carola # gmail.com>
 *          Mike JS. Choi <mkchoi212 # icloud.com>
 *
 * Refer to the COPYING file of the official project for license.
 *****************************************************************************/

extension Notification.Name {
    static let VLCTracksDidChangeNotification = Notification.Name("kTracksDidChangeNotification")
    static let VLCAllVideosDidChangeNotification = Notification.Name("kAllVideosDidChangeNotification")
}

// These are the delegate and datasource calls from the MediaViewController
extension VLCMediaViewController: UICollectionViewDelegateFlowLayout {

    // MARK: - UICollectionViewDataSource
    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return Int(services.mediaDataSource.numberOfFiles(subcategory: mediaType.subcategory))
    }

    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        if let playlistCell = collectionView.dequeueReusableCell(withReuseIdentifier: VLCPlaylistCollectionViewCell.cellIdentifier(), for: indexPath) as? VLCPlaylistCollectionViewCell {
            if let mediaObject = services.mediaDataSource.object(at: indexPath.row, subcategory: mediaType.subcategory) as? NSManagedObject {
                playlistCell.mediaObject = mediaObject
            }
            return playlistCell
        }
        return UICollectionViewCell()
    }

    // MARK: - UICollectionViewDelegate
    override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        if let mediaObject = services.mediaDataSource.object(at: indexPath.row, subcategory: mediaType.subcategory) as? NSManagedObject {
            delegate?.mediaViewControllerDidSelectMediaObject(self, mediaObject: mediaObject)
        }
    }

    // MARK: - UICollectionViewDelegateFlowLayout
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {

        let numberOfCells: CGFloat = collectionView.traitCollection.horizontalSizeClass == .regular ? 3.0 : 2.0
        let aspectRatio: CGFloat = 10.0 / 16.0

        // We have the number of cells and we always have numberofCells + 1 padding spaces. -pad-[Cell]-pad-[Cell]-pad-
        // we then have the entire padding, we divide the entire padding by the number of Cells to know how much needs to be substracted from ech cell
        // since this might be an uneven number we ceil
        var cellWidth = collectionView.bounds.size.width / numberOfCells
        cellWidth = cellWidth - ceil(((numberOfCells + 1) * cellPadding) / numberOfCells)

        return CGSize(width: cellWidth, height: cellWidth * aspectRatio)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        return UIEdgeInsets(top: cellPadding, left: cellPadding, bottom: cellPadding, right: cellPadding)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return cellPadding
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return cellPadding
    }
}