snapshot

Signed-off-by: Joseph Mattello <mail@joemattiello.com>

SideStoreApp/Sources/SideStoreUIKit/Browse/BrowseCollectionViewCell.swift

@@ -0,0 +1,94 @@
+//
+//  BrowseCollectionViewCell.swift
+//  AltStore
+//
+//  Created by Riley Testut on 7/15/19.
+//  Copyright © 2019 Riley Testut. All rights reserved.
+//
+
+import UIKit
+
+import RoxasUIKit
+import OSLog
+#if canImport(Logging)
+import Logging
+#endif
+
+import Nuke
+
+@objc final class BrowseCollectionViewCell: UICollectionViewCell {
+    var imageURLs: [URL] = [] {
+        didSet {
+            dataSource.items = imageURLs as [NSURL]
+        }
+    }
+
+    private lazy var dataSource = self.makeDataSource()
+
+    @IBOutlet var bannerView: AppBannerView!
+    @IBOutlet var subtitleLabel: UILabel!
+
+    @IBOutlet private(set) var screenshotsCollectionView: UICollectionView!
+
+    override func awakeFromNib() {
+        super.awakeFromNib()
+
+        contentView.preservesSuperviewLayoutMargins = true
+
+        // Must be registered programmatically, not in BrowseCollectionViewCell.xib, or else it'll throw an exception 🤷‍♂️.
+        screenshotsCollectionView.register(ScreenshotCollectionViewCell.self, forCellWithReuseIdentifier: RSTCellContentGenericCellIdentifier)
+
+        screenshotsCollectionView.delegate = self
+        screenshotsCollectionView.dataSource = dataSource
+        screenshotsCollectionView.prefetchDataSource = dataSource
+    }
+}
+
+private extension BrowseCollectionViewCell {
+    func makeDataSource() -> RSTArrayCollectionViewPrefetchingDataSource<NSURL, UIImage> {
+        let dataSource = RSTArrayCollectionViewPrefetchingDataSource<NSURL, UIImage>(items: [])
+        dataSource.cellConfigurationHandler = { cell, _, _ in
+            let cell = cell as! ScreenshotCollectionViewCell
+            cell.imageView.image = nil
+            cell.imageView.isIndicatingActivity = true
+        }
+        dataSource.prefetchHandler = { imageURL, _, completionHandler in
+            RSTAsyncBlockOperation { operation in
+                let request = ImageRequest(url: imageURL as URL, processor: .screenshot)
+                ImagePipeline.shared.loadImage(with: request, progress: nil, completion: { response, error in
+                    guard !operation.isCancelled else { return operation.finish() }
+
+                    if let image = response?.image {
+                        completionHandler(image, nil)
+                    } else {
+                        completionHandler(nil, error)
+                    }
+                })
+            }
+        }
+        dataSource.prefetchCompletionHandler = { cell, image, _, error in
+            let cell = cell as! ScreenshotCollectionViewCell
+            cell.imageView.isIndicatingActivity = false
+            cell.imageView.image = image
+
+            if let error = error {
+                os_log("Error loading image: %@", type: .error , error.localizedDescription)
+            }
+        }
+
+        return dataSource
+    }
+}
+
+extension BrowseCollectionViewCell: UICollectionViewDelegateFlowLayout {
+    func collectionView(_ collectionView: UICollectionView, layout _: UICollectionViewLayout, sizeForItemAt _: IndexPath) -> CGSize {
+        // Assuming 9.0 / 16.0 ratio for now.
+        let aspectRatio: CGFloat = 9.0 / 16.0
+
+        let itemHeight = collectionView.bounds.height
+        let itemWidth = itemHeight * aspectRatio
+
+        let size = CGSize(width: itemWidth.rounded(.down), height: itemHeight.rounded(.down))
+        return size
+    }
+}