// // Copyright (c) 2019 Open Whisper Systems. All rights reserved. // import UIKit import PromiseKit // Objc wrapper for the MediaGalleryItem struct @objc public class GalleryItemBox: NSObject { public let value: MediaGalleryItem init(_ value: MediaGalleryItem) { self.value = value } @objc public var attachmentStream: TSAttachmentStream { return value.attachmentStream } } private class Box { var value: A init(_ val: A) { self.value = val } } fileprivate extension MediaDetailViewController { fileprivate var galleryItem: MediaGalleryItem { return self.galleryItemBox.value } } class MediaPageViewController: UIPageViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate, MediaDetailViewControllerDelegate, MediaGalleryDataSourceDelegate { private weak var mediaGalleryDataSource: MediaGalleryDataSource? private var cachedPages: [MediaGalleryItem: MediaDetailViewController] = [:] private var initialPage: MediaDetailViewController! public var currentViewController: MediaDetailViewController { return viewControllers!.first as! MediaDetailViewController } public var currentItem: MediaGalleryItem! { return currentViewController.galleryItemBox.value } public func setCurrentItem(_ item: MediaGalleryItem, direction: UIPageViewController.NavigationDirection, animated isAnimated: Bool) { guard let galleryPage = self.buildGalleryPage(galleryItem: item) else { owsFailDebug("unexpectedly unable to build new gallery page") return } updateTitle(item: item) updateCaption(item: item) setViewControllers([galleryPage], direction: direction, animated: isAnimated) updateFooterBarButtonItems(isPlayingVideo: false) updateMediaRail() } private let uiDatabaseConnection: YapDatabaseConnection private let showAllMediaButton: Bool private let sliderEnabled: Bool init(initialItem: MediaGalleryItem, mediaGalleryDataSource: MediaGalleryDataSource, uiDatabaseConnection: YapDatabaseConnection, options: MediaGalleryOption) { assert(uiDatabaseConnection.isInLongLivedReadTransaction()) self.uiDatabaseConnection = uiDatabaseConnection self.showAllMediaButton = options.contains(.showAllMediaButton) self.sliderEnabled = options.contains(.sliderEnabled) self.mediaGalleryDataSource = mediaGalleryDataSource let kSpacingBetweenItems: CGFloat = 20 let options: [UIPageViewController.OptionsKey: Any] = [.interPageSpacing: kSpacingBetweenItems] super.init(transitionStyle: .scroll, navigationOrientation: .horizontal, options: options) self.dataSource = self self.delegate = self guard let initialPage = self.buildGalleryPage(galleryItem: initialItem) else { owsFailDebug("unexpectedly unable to build initial gallery item") return } self.initialPage = initialPage self.setViewControllers([initialPage], direction: .forward, animated: false, completion: nil) } @available(*, unavailable, message: "Unimplemented") required init?(coder: NSCoder) { notImplemented() } deinit { Logger.debug("deinit") } // MARK: - Subview // MARK: Bottom Bar var bottomContainer: UIView! var footerBar: UIToolbar! let captionContainerView: CaptionContainerView = CaptionContainerView() var galleryRailView: GalleryRailView = GalleryRailView() var pagerScrollView: UIScrollView! // MARK: UIViewController overrides override func viewDidLoad() { super.viewDidLoad() // Navigation // Note: using a custom leftBarButtonItem breaks the interactive pop gesture, but we don't want to be able // to swipe to go back in the pager view anyway, instead swiping back should show the next page. let backButton = OWSViewController.createOWSBackButton(withTarget: self, selector: #selector(didPressDismissButton)) self.navigationItem.leftBarButtonItem = backButton self.navigationItem.titleView = portraitHeaderView if showAllMediaButton { self.navigationItem.rightBarButtonItem = UIBarButtonItem(title: MediaStrings.allMedia, style: .plain, target: self, action: #selector(didPressAllMediaButton)) } // Even though bars are opaque, we want content to be layed out behind them. // The bars might obscure part of the content, but they can easily be hidden by tapping // The alternative would be that content would shift when the navbars hide. self.extendedLayoutIncludesOpaqueBars = true self.automaticallyAdjustsScrollViewInsets = false // Get reference to paged content which lives in a scrollView created by the superclass // We show/hide this content during presentation for view in self.view.subviews { if let pagerScrollView = view as? UIScrollView { self.pagerScrollView = pagerScrollView } } // Hack to avoid "page" bouncing when not in gallery view. // e.g. when getting to media details via message details screen, there's only // one "Page" so the bounce doesn't make sense. pagerScrollView.isScrollEnabled = sliderEnabled pagerScrollViewContentOffsetObservation = pagerScrollView.observe(\.contentOffset, options: [.new]) { [weak self] _, change in guard let strongSelf = self else { return } strongSelf.pagerScrollView(strongSelf.pagerScrollView, contentOffsetDidChange: change) } // Views pagerScrollView.backgroundColor = Colors.navigationBarBackground view.backgroundColor = Colors.navigationBarBackground captionContainerView.delegate = self updateCaptionContainerVisibility() galleryRailView.delegate = self galleryRailView.autoSetDimension(.height, toSize: 72) let footerBar = self.makeClearToolbar() self.footerBar = footerBar footerBar.tintColor = Colors.text footerBar.setBackgroundImage(UIImage(), forToolbarPosition: .any, barMetrics: UIBarMetrics.default) footerBar.setShadowImage(UIImage(), forToolbarPosition: .any) footerBar.isTranslucent = false footerBar.barTintColor = Colors.navigationBarBackground let bottomContainer = UIView() self.bottomContainer = bottomContainer bottomContainer.backgroundColor = Colors.navigationBarBackground let bottomStack = UIStackView(arrangedSubviews: [captionContainerView, galleryRailView, footerBar]) bottomStack.axis = .vertical bottomContainer.addSubview(bottomStack) bottomStack.autoPinEdgesToSuperviewEdges() self.view.addSubview(bottomContainer) bottomContainer.autoPinWidthToSuperview() bottomContainer.autoPinEdge(.bottom, to: .bottom, of: view) footerBar.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor).isActive = true footerBar.autoSetDimension(.height, toSize: 44) updateTitle() updateCaption(item: currentItem) updateMediaRail() updateFooterBarButtonItems(isPlayingVideo: true) // Gestures let verticalSwipe = UISwipeGestureRecognizer(target: self, action: #selector(didSwipeView)) verticalSwipe.direction = [.up, .down] view.addGestureRecognizer(verticalSwipe) let navigationBar = navigationController!.navigationBar navigationBar.setBackgroundImage(UIImage(), for: UIBarMetrics.default) navigationBar.shadowImage = UIImage() navigationBar.isTranslucent = false navigationBar.barTintColor = Colors.navigationBarBackground } override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) { super.viewWillTransition(to: size, with: coordinator) let isLandscape = size.width > size.height self.navigationItem.titleView = isLandscape ? nil : self.portraitHeaderView } override func didReceiveMemoryWarning() { Logger.info("") super.didReceiveMemoryWarning() self.cachedPages = [:] } // MARK: KVO var pagerScrollViewContentOffsetObservation: NSKeyValueObservation? func pagerScrollView(_ pagerScrollView: UIScrollView, contentOffsetDidChange change: NSKeyValueObservedChange) { guard let newValue = change.newValue else { owsFailDebug("newValue was unexpectedly nil") return } let width = pagerScrollView.frame.size.width guard width > 0 else { return } let ratioComplete = abs((newValue.x - width) / width) captionContainerView.updatePagerTransition(ratioComplete: ratioComplete) } // MARK: View Helpers public func willBePresentedAgain() { updateFooterBarButtonItems(isPlayingVideo: false) } public func wasPresented() { let currentViewController = self.currentViewController if currentViewController.galleryItem.isVideo { currentViewController.playVideo() } } private func makeClearToolbar() -> UIToolbar { let toolbar = UIToolbar() toolbar.backgroundColor = Colors.navigationBarBackground // hide 1px top-border toolbar.clipsToBounds = true return toolbar } private var shouldHideToolbars: Bool = false { didSet { if (oldValue == shouldHideToolbars) { return } // Hiding the status bar affects the positioning of the navbar. We don't want to show that in an animation, it's // better to just have everythign "flit" in/out. UIApplication.shared.setStatusBarHidden(shouldHideToolbars, with: .none) self.navigationController?.setNavigationBarHidden(shouldHideToolbars, animated: false) UIView.animate(withDuration: 0.1) { self.currentViewController.setShouldHideToolbars(self.shouldHideToolbars) self.bottomContainer.isHidden = self.shouldHideToolbars } } } // MARK: Bar Buttons lazy var shareBarButton: UIBarButtonItem = { let shareBarButton = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(didPressShare)) shareBarButton.tintColor = Theme.darkThemePrimaryColor return shareBarButton }() lazy var deleteBarButton: UIBarButtonItem = { let deleteBarButton = UIBarButtonItem(barButtonSystemItem: .trash, target: self, action: #selector(didPressDelete)) deleteBarButton.tintColor = Theme.darkThemePrimaryColor return deleteBarButton }() func buildFlexibleSpace() -> UIBarButtonItem { return UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil) } lazy var videoPlayBarButton: UIBarButtonItem = { let videoPlayBarButton = UIBarButtonItem(barButtonSystemItem: .play, target: self, action: #selector(didPressPlayBarButton)) videoPlayBarButton.tintColor = Theme.darkThemePrimaryColor return videoPlayBarButton }() lazy var videoPauseBarButton: UIBarButtonItem = { let videoPauseBarButton = UIBarButtonItem(barButtonSystemItem: .pause, target: self, action: #selector(didPressPauseBarButton)) videoPauseBarButton.tintColor = Theme.darkThemePrimaryColor return videoPauseBarButton }() private func updateFooterBarButtonItems(isPlayingVideo: Bool) { // TODO do we still need this? seems like a vestige // from when media detail view was used for attachment approval if self.footerBar == nil { owsFailDebug("No footer bar visible.") return } var toolbarItems: [UIBarButtonItem] = [ shareBarButton, buildFlexibleSpace() ] if (self.currentItem.isVideo) { toolbarItems += [ isPlayingVideo ? self.videoPauseBarButton : self.videoPlayBarButton, buildFlexibleSpace() ] } toolbarItems.append(deleteBarButton) self.footerBar.setItems(toolbarItems, animated: false) } func updateMediaRail() { guard let currentItem = self.currentItem else { owsFailDebug("currentItem was unexpectedly nil") return } galleryRailView.configureCellViews(itemProvider: currentItem.album, focusedItem: currentItem, cellViewBuilder: { _ in return GalleryRailCellView() }) } // MARK: Actions @objc public func didPressAllMediaButton(sender: Any) { Logger.debug("") currentViewController.stopAnyVideo() guard let mediaGalleryDataSource = self.mediaGalleryDataSource else { owsFailDebug("mediaGalleryDataSource was unexpectedly nil") return } mediaGalleryDataSource.showAllMedia(focusedItem: currentItem) } @objc public func didSwipeView(sender: Any) { Logger.debug("") self.dismissSelf(animated: true) } @objc public func didPressDismissButton(_ sender: Any) { dismissSelf(animated: true) } @objc public func didPressShare(_ sender: Any) { guard let currentViewController = self.viewControllers?[0] as? MediaDetailViewController else { owsFailDebug("currentViewController was unexpectedly nil") return } let attachmentStream = currentViewController.galleryItem.attachmentStream AttachmentSharing.showShareUI(forAttachment: attachmentStream) } @objc public func didPressDelete(_ sender: Any) { guard let currentViewController = self.viewControllers?[0] as? MediaDetailViewController else { owsFailDebug("currentViewController was unexpectedly nil") return } guard let mediaGalleryDataSource = self.mediaGalleryDataSource else { owsFailDebug("mediaGalleryDataSource was unexpectedly nil") return } let actionSheet = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet) let deleteAction = UIAlertAction(title: NSLocalizedString("TXT_DELETE_TITLE", comment: ""), style: .destructive) { _ in let deletedItem = currentViewController.galleryItem mediaGalleryDataSource.delete(items: [deletedItem], initiatedBy: self) } actionSheet.addAction(OWSAlerts.cancelAction) actionSheet.addAction(deleteAction) self.presentAlert(actionSheet) } // MARK: MediaGalleryDataSourceDelegate func mediaGalleryDataSource(_ mediaGalleryDataSource: MediaGalleryDataSource, willDelete items: [MediaGalleryItem], initiatedBy: AnyObject) { Logger.debug("") guard let currentItem = self.currentItem else { owsFailDebug("currentItem was unexpectedly nil") return } guard items.contains(currentItem) else { Logger.debug("irrelevant item") return } // If we setCurrentItem with (animated: true) while this VC is in the background, then // the next/previous cache isn't expired, and we're able to swipe back to the just-deleted vc. // So to get the correct behavior, we should only animate these transitions when this // vc is in the foreground let isAnimated = initiatedBy === self if !self.sliderEnabled { // In message details, which doesn't use the slider, so don't swap pages. } else if let nextItem = mediaGalleryDataSource.galleryItem(after: currentItem) { self.setCurrentItem(nextItem, direction: .forward, animated: isAnimated) } else if let previousItem = mediaGalleryDataSource.galleryItem(before: currentItem) { self.setCurrentItem(previousItem, direction: .reverse, animated: isAnimated) } else { // else we deleted the last piece of media, return to the conversation view self.dismissSelf(animated: true) } } func mediaGalleryDataSource(_ mediaGalleryDataSource: MediaGalleryDataSource, deletedSections: IndexSet, deletedItems: [IndexPath]) { // no-op } @objc public func didPressPlayBarButton(_ sender: Any) { guard let currentViewController = self.viewControllers?[0] as? MediaDetailViewController else { owsFailDebug("currentViewController was unexpectedly nil") return } currentViewController.didPressPlayBarButton(sender) } @objc public func didPressPauseBarButton(_ sender: Any) { guard let currentViewController = self.viewControllers?[0] as? MediaDetailViewController else { owsFailDebug("currentViewController was unexpectedly nil") return } currentViewController.didPressPauseBarButton(sender) } // MARK: UIPageViewControllerDelegate var pendingViewController: MediaDetailViewController? public func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) { Logger.debug("") assert(pendingViewControllers.count == 1) pendingViewControllers.forEach { viewController in guard let pendingViewController = viewController as? MediaDetailViewController else { owsFailDebug("unexpected mediaDetailViewController: \(viewController)") return } self.pendingViewController = pendingViewController if let pendingCaptionText = pendingViewController.galleryItem.captionForDisplay, pendingCaptionText.count > 0 { self.captionContainerView.pendingText = pendingCaptionText } else { self.captionContainerView.pendingText = nil } // Ensure upcoming page respects current toolbar status pendingViewController.setShouldHideToolbars(self.shouldHideToolbars) } } public func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted: Bool) { Logger.debug("") assert(previousViewControllers.count == 1) previousViewControllers.forEach { viewController in guard let previousPage = viewController as? MediaDetailViewController else { owsFailDebug("unexpected mediaDetailViewController: \(viewController)") return } // Do any cleanup for the no-longer visible view controller if transitionCompleted { pendingViewController = nil // This can happen when trying to page past the last (or first) view controller // In that case, we don't want to change the captionView. if (previousPage != currentViewController) { captionContainerView.completePagerTransition() } updateTitle() updateMediaRail() previousPage.zoomOut(animated: false) previousPage.stopAnyVideo() updateFooterBarButtonItems(isPlayingVideo: false) } else { captionContainerView.pendingText = nil } } } // MARK: UIPageViewControllerDataSource public func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? { Logger.debug("") guard let previousDetailViewController = viewController as? MediaDetailViewController else { owsFailDebug("unexpected viewController: \(viewController)") return nil } guard let mediaGalleryDataSource = self.mediaGalleryDataSource else { owsFailDebug("mediaGalleryDataSource was unexpectedly nil") return nil } let previousItem = previousDetailViewController.galleryItem guard let nextItem: MediaGalleryItem = mediaGalleryDataSource.galleryItem(before: previousItem) else { return nil } guard let nextPage: MediaDetailViewController = buildGalleryPage(galleryItem: nextItem) else { return nil } return nextPage } public func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? { Logger.debug("") guard let previousDetailViewController = viewController as? MediaDetailViewController else { owsFailDebug("unexpected viewController: \(viewController)") return nil } guard let mediaGalleryDataSource = self.mediaGalleryDataSource else { owsFailDebug("mediaGalleryDataSource was unexpectedly nil") return nil } let previousItem = previousDetailViewController.galleryItem guard let nextItem = mediaGalleryDataSource.galleryItem(after: previousItem) else { // no more pages return nil } guard let nextPage: MediaDetailViewController = buildGalleryPage(galleryItem: nextItem) else { return nil } return nextPage } private func buildGalleryPage(galleryItem: MediaGalleryItem) -> MediaDetailViewController? { if let cachedPage = cachedPages[galleryItem] { Logger.debug("cache hit.") return cachedPage } Logger.debug("cache miss.") var fetchedItem: ConversationViewItem? self.uiDatabaseConnection.read { transaction in let message = galleryItem.message let thread = message.thread(with: transaction) let conversationStyle = ConversationStyle(thread: thread) fetchedItem = ConversationInteractionViewItem(interaction: message, isGroupThread: thread.isGroupThread(), transaction: transaction, conversationStyle: conversationStyle) } guard let viewItem = fetchedItem else { owsFailDebug("viewItem was unexpectedly nil") return nil } let viewController = MediaDetailViewController(galleryItemBox: GalleryItemBox(galleryItem), viewItem: viewItem) viewController.delegate = self cachedPages[galleryItem] = viewController return viewController } public func dismissSelf(animated isAnimated: Bool, completion: (() -> Void)? = nil) { // Swapping mediaView for presentationView will be perceptible if we're not zoomed out all the way. // currentVC currentViewController.zoomOut(animated: true) currentViewController.stopAnyVideo() guard let mediaGalleryDataSource = self.mediaGalleryDataSource else { owsFailDebug("mediaGalleryDataSource was unexpectedly nil") self.presentingViewController?.dismiss(animated: true) return } if IsLandscapeOrientationEnabled() { mediaGalleryDataSource.dismissMediaDetailViewController(self, animated: isAnimated, completion: completion) } else { mediaGalleryDataSource.dismissMediaDetailViewController(self, animated: isAnimated) { UIDevice.current.ows_setOrientation(.portrait) completion?() } } } // MARK: MediaDetailViewControllerDelegate @objc public func mediaDetailViewControllerDidTapMedia(_ mediaDetailViewController: MediaDetailViewController) { Logger.debug("") self.shouldHideToolbars = !self.shouldHideToolbars } public func mediaDetailViewController(_ mediaDetailViewController: MediaDetailViewController, requestDelete attachment: TSAttachment) { guard let mediaGalleryDataSource = self.mediaGalleryDataSource else { owsFailDebug("mediaGalleryDataSource was unexpectedly nil") self.presentingViewController?.dismiss(animated: true) return } guard let galleryItem = self.mediaGalleryDataSource?.galleryItems.first(where: { $0.attachmentStream == attachment }) else { owsFailDebug("galleryItem was unexpectedly nil") self.presentingViewController?.dismiss(animated: true) return } dismissSelf(animated: true) { mediaGalleryDataSource.delete(items: [galleryItem], initiatedBy: self) } } public func mediaDetailViewController(_ mediaDetailViewController: MediaDetailViewController, isPlayingVideo: Bool) { guard mediaDetailViewController == currentViewController else { Logger.verbose("ignoring stale delegate.") return } self.shouldHideToolbars = isPlayingVideo self.updateFooterBarButtonItems(isPlayingVideo: isPlayingVideo) } // MARK: Dynamic Header private func senderName(message: TSMessage) -> String { switch message { case let incomingMessage as TSIncomingMessage: let hexEncodedPublicKey = incomingMessage.authorId if incomingMessage.thread.isGroupThread() { let publicChat = Storage.shared.getOpenGroup(for: incomingMessage.thread.uniqueId!) if let publicChat = publicChat { return UserDisplayNameUtilities.getPublicChatDisplayName(for: hexEncodedPublicKey, in: publicChat.channel, on: publicChat.server) ?? hexEncodedPublicKey } else { return hexEncodedPublicKey } } else { return UserDisplayNameUtilities.getPrivateChatDisplayName(for: hexEncodedPublicKey) ?? hexEncodedPublicKey } case is TSOutgoingMessage: return NSLocalizedString("MEDIA_GALLERY_SENDER_NAME_YOU", comment: "Short sender label for media sent by you") default: owsFailDebug("Unknown message type: \(type(of: message))") return "" } } private lazy var dateFormatter: DateFormatter = { let formatter = DateFormatter() formatter.dateStyle = .short formatter.timeStyle = .short return formatter }() lazy private var portraitHeaderNameLabel: UILabel = { let label = UILabel() label.textColor = Colors.text label.font = .systemFont(ofSize: Values.mediumFontSize) label.textAlignment = .center label.adjustsFontSizeToFitWidth = true label.minimumScaleFactor = 0.8 return label }() lazy private var portraitHeaderDateLabel: UILabel = { let label = UILabel() label.textColor = Colors.text label.font = .systemFont(ofSize: Values.verySmallFontSize) label.textAlignment = .center label.adjustsFontSizeToFitWidth = true label.minimumScaleFactor = 0.8 return label }() private lazy var portraitHeaderView: UIView = { let stackView = UIStackView() stackView.axis = .vertical stackView.alignment = .center stackView.spacing = 0 stackView.distribution = .fillProportionally stackView.addArrangedSubview(portraitHeaderNameLabel) stackView.addArrangedSubview(portraitHeaderDateLabel) let containerView = UIView() containerView.layoutMargins = UIEdgeInsets(top: 2, left: 8, bottom: 4, right: 8) containerView.addSubview(stackView) stackView.autoPinEdge(toSuperviewMargin: .top, relation: .greaterThanOrEqual) stackView.autoPinEdge(toSuperviewMargin: .trailing, relation: .greaterThanOrEqual) stackView.autoPinEdge(toSuperviewMargin: .bottom, relation: .greaterThanOrEqual) stackView.autoPinEdge(toSuperviewMargin: .leading, relation: .greaterThanOrEqual) stackView.setContentHuggingHigh() stackView.autoCenterInSuperview() return containerView }() private func updateTitle() { guard let currentItem = self.currentItem else { owsFailDebug("currentItem was unexpectedly nil") return } updateTitle(item: currentItem) } private func updateCaption(item: MediaGalleryItem) { captionContainerView.currentText = item.captionForDisplay } private func updateTitle(item: MediaGalleryItem) { let name = senderName(message: item.message) portraitHeaderNameLabel.text = name // use sent date let date = Date(timeIntervalSince1970: Double(item.message.timestamp) / 1000) let formattedDate = dateFormatter.string(from: date) portraitHeaderDateLabel.text = formattedDate let landscapeHeaderFormat = NSLocalizedString("MEDIA_GALLERY_LANDSCAPE_TITLE_FORMAT", comment: "embeds {{sender name}} and {{sent datetime}}, e.g. 'Sarah on 10/30/18, 3:29'") let landscapeHeaderText = String(format: landscapeHeaderFormat, name, formattedDate) self.title = landscapeHeaderText self.navigationItem.title = landscapeHeaderText if #available(iOS 11, *) { // Do nothing, on iOS11+, autolayout grows the stack view as necessary. } else { // Size the titleView to be large enough to fit the widest label, // but no larger. If we go for a "full width" label, our title view // will not be centered (since the left and right bar buttons have different widths) portraitHeaderNameLabel.sizeToFit() portraitHeaderDateLabel.sizeToFit() let width = max(portraitHeaderNameLabel.frame.width, portraitHeaderDateLabel.frame.width) let headerFrame: CGRect = CGRect(x: 0, y: 0, width: width, height: 44) portraitHeaderView.frame = headerFrame } } } extension MediaGalleryItem: GalleryRailItem { public func buildRailItemView() -> UIView { let imageView = UIImageView() imageView.contentMode = .scaleAspectFill getRailImage().map { [weak imageView] image in guard let imageView = imageView else { return } imageView.image = image }.retainUntilComplete() return imageView } public func getRailImage() -> Guarantee { return Guarantee { fulfill in if let image = self.thumbnailImage(async: { fulfill($0) }) { fulfill(image) } } } } extension MediaGalleryAlbum: GalleryRailItemProvider { var railItems: [GalleryRailItem] { return self.items } } extension MediaPageViewController: GalleryRailViewDelegate { func galleryRailView(_ galleryRailView: GalleryRailView, didTapItem imageRailItem: GalleryRailItem) { guard let targetItem = imageRailItem as? MediaGalleryItem else { owsFailDebug("unexpected imageRailItem: \(imageRailItem)") return } let direction: UIPageViewController.NavigationDirection direction = currentItem.albumIndex < targetItem.albumIndex ? .forward : .reverse self.setCurrentItem(targetItem, direction: direction, animated: true) } } extension MediaPageViewController: CaptionContainerViewDelegate { func captionContainerViewDidUpdateText(_ captionContainerView: CaptionContainerView) { updateCaptionContainerVisibility() } // MARK: Helpers func updateCaptionContainerVisibility() { if let currentText = captionContainerView.currentText, currentText.count > 0 { captionContainerView.isHidden = false return } if let pendingText = captionContainerView.pendingText, pendingText.count > 0 { captionContainerView.isHidden = false return } captionContainerView.isHidden = true } }