feat: Improve shared media

NextcloudTalk/Chat/Chat views/Giphy/GiphyPickerViewController.swift

@@ -60,8 +60,8 @@ class GiphyPickerViewController: UIViewController {
         return searchController
     }()
 
-    private lazy var waterfallLayout: GiphyWaterfallLayout = {
-        let layout = GiphyWaterfallLayout()
+    private lazy var waterfallLayout: WaterfallLayout = {
+        let layout = WaterfallLayout()
         layout.delegate = self
         return layout
     }()
@@ -432,13 +432,13 @@ extension GiphyPickerViewController: UICollectionViewDataSource, UICollectionVie
     }
 }
 
-// MARK: - GiphyWaterfallLayoutDelegate
+// MARK: - WaterfallLayoutDelegate
 
-extension GiphyPickerViewController: GiphyWaterfallLayoutDelegate {
+extension GiphyPickerViewController: WaterfallLayoutDelegate {
 
-    func waterfallLayout(_ layout: GiphyWaterfallLayout, aspectRatioForItemAt index: Int) -> CGFloat {
-        guard index < self.items.count else { return Self.fallbackAspectRatio }
+    func waterfallLayout(_ layout: WaterfallLayout, aspectRatioForItemAt indexPath: IndexPath) -> CGFloat {
+        guard indexPath.item < self.items.count else { return Self.fallbackAspectRatio }
 
-        return self.items[index].aspectRatio
+        return self.items[indexPath.item].aspectRatio
     }
 }

NextcloudTalk/Chat/ChatFileDownloadObserver.swift

@@ -0,0 +1,48 @@
+//
+// SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+
+import Foundation
+
+/// Follows the download of one file through the notifications NCChatFileController posts
+class ChatFileDownloadObserver {
+
+    enum Change {
+        case isDownloading(Bool)
+        /// nil while the size of the download is unknown
+        case progress(Float?)
+    }
+
+    var fileParameter: NCMessageFileParameter?
+
+    private let onChange: (Change) -> Void
+    private var observers: [NSObjectProtocol] = []
+
+    init(onChange: @escaping (Change) -> Void) {
+        self.onChange = onChange
+
+        // Download progress can be reported off the main queue
+        self.observers.append(NotificationCenter.default.addObserver(forName: .NCChatFileControllerDidChangeIsDownloading, object: nil, queue: .main) { [weak self] notification in
+            guard let status = self?.status(from: notification) else { return }
+
+            self?.onChange(.isDownloading(status.isDownloading))
+        })
+
+        self.observers.append(NotificationCenter.default.addObserver(forName: .NCChatFileControllerDidChangeDownloadProgress, object: nil, queue: .main) { [weak self] notification in
+            guard let status = self?.status(from: notification) else { return }
+
+            self?.onChange(.progress(status.canReportProgress ? Float(status.downloadProgress) : nil))
+        })
+    }
+
+    deinit {
+        self.observers.forEach { NotificationCenter.default.removeObserver($0) }
+    }
+
+    private func status(from notification: Notification) -> NCChatFileStatus? {
+        guard let fileParameter = self.fileParameter else { return nil }
+
+        return NCChatFileStatus.getStatus(from: notification, for: fileParameter)
+    }
+}

NextcloudTalk/Media Viewer/NCMediaViewerPageViewController.swift

@@ -157,6 +157,10 @@ import SwiftyGif
         return videoPlayButton
     }()
 
+    private lazy var downloadObserver = ChatFileDownloadObserver { [weak self] change in
+        self?.downloadDidChange(change)
+    }
+
     init(message: NCChatMessage, account: TalkAccount) {
         self.message = message
         self.account = account
@@ -193,7 +197,7 @@ import SwiftyGif
 
         self.navigationItem.title = self.message.file()?.name
 
-        NotificationCenter.default.addObserver(self, selector: #selector(didChangeDownloadProgress(notification:)), name: NSNotification.Name.NCChatFileControllerDidChangeDownloadProgress, object: nil)
+        self.downloadObserver.fileParameter = self.message.file()
 
         self.startLoading()
 
@@ -662,17 +666,12 @@ import SwiftyGif
         }
     }
 
-    func didChangeDownloadProgress(notification: Notification) {
-        DispatchQueue.main.async {
-            guard let fileParameter = self.message.file(),
-                  let receivedStatus = NCChatFileStatus.getStatus(from: notification, for: fileParameter),
-                  receivedStatus.canReportProgress
-            else { return }
+    private func downloadDidChange(_ change: ChatFileDownloadObserver.Change) {
+        guard case .progress(let progress?) = change else { return }
 
-            self.activityIndicator.indicatorMode = .determinate
-            self.activityIndicator.setProgress(Float(receivedStatus.downloadProgress), animated: true)
-            self.downloadIndicator.setProgress(Float(receivedStatus.downloadProgress))
-        }
+        self.activityIndicator.indicatorMode = .determinate
+        self.activityIndicator.setProgress(progress, animated: true)
+        self.downloadIndicator.setProgress(progress)
     }
 
     // MARK: - NCChatFileController delegate

NextcloudTalk/Media Viewer/NCMediaViewerViewController.swift

@@ -6,6 +6,15 @@
 import Foundation
 import UIKit
 
+/// Decides which media the viewer swipes to, instead of the chat messages stored for the room
+@objc protocol MediaViewerMessageSource: AnyObject {
+    /// The closest older message to show before `message`, or nil to stop there
+    func mediaViewerMessage(before message: NCChatMessage) -> NCChatMessage?
+
+    /// The closest newer message to show after `message`, or nil to stop there
+    func mediaViewerMessage(after message: NCChatMessage) -> NCChatMessage?
+}
+
 @objcMembers class NCMediaViewerViewController: UIViewController,
                                                 UIPageViewControllerDelegate,
                                                 UIPageViewControllerDataSource,
@@ -15,6 +24,10 @@ import UIKit
     private let account: TalkAccount
     private let pageController = UIPageViewController(transitionStyle: .scroll, navigationOrientation: .horizontal)
     private var initialMessage: NCChatMessage
+    private weak var messageSource: MediaViewerMessageSource?
+    // Resetting the data source while a swipe animates could disturb it, so that waits for the swipe to end
+    private var isTransitioning = false
+    private var needsAdjacentPagesReload = false
 
     private lazy var shareButton = {
         let shareButton = UIBarButtonItem(title: nil, style: .plain, target: nil, action: nil)
@@ -72,10 +85,11 @@ import UIKit
         return showMessageButton
     }()
 
-    init(initialMessage: NCChatMessage, room: NCRoom, account: TalkAccount) {
+    init(initialMessage: NCChatMessage, room: NCRoom, account: TalkAccount, messageSource: MediaViewerMessageSource? = nil) {
         self.room = room
         self.initialMessage = initialMessage
         self.account = account
+        self.messageSource = messageSource
 
         super.init(nibName: nil, bundle: nil)
     }
@@ -152,6 +166,20 @@ import UIKit
         return self.pageController.viewControllers?.first as? NCMediaViewerPageViewController
     }
 
+    /// For a message source that got more messages after it reported the end
+    func reloadAdjacentPages() {
+        guard !self.isTransitioning else {
+            self.needsAdjacentPagesReload = true
+            return
+        }
+
+        self.needsAdjacentPagesReload = false
+
+        // The page controller keeps a nil neighbour until its data source is set again, which leaves the current page alone
+        self.pageController.dataSource = nil
+        self.pageController.dataSource = self
+    }
+
     // MARK: - PageViewController delegate
 
     func getAllFileMessages() -> RLMResults<AnyObject>? {
@@ -163,22 +191,29 @@ import UIKit
         return messages
     }
 
+    /// Whether the viewer can show the file of `message`, formats only VLC can play excluded
+    static func canShowMedia(of message: NCChatMessage) -> Bool {
+        guard let file = message.file(), let filePath = file.path else { return false }
+
+        let fileType = file.mimetype ?? ""
+        let isSupportedMedia = NCUtils.isImage(fileType: fileType) || NCUtils.isVideo(fileType: fileType)
+        let isUnsupportedExtension = VLCKitVideoViewController.supportedFileExtensions.contains(URL(fileURLWithPath: filePath).pathExtension.lowercased())
+
+        return isSupportedMedia && !isUnsupportedExtension
+    }
+
     func getPreviousFileMessage(from message: NCChatMessage) -> NCChatMessage? {
+        if let messageSource {
+            return messageSource.mediaViewerMessage(before: message)
+        }
+
         let prevQuery = NSPredicate(format: "messageId < %ld", message.messageId)
 
         guard let queriedObjects = self.getAllFileMessages()?.objects(with: prevQuery) else { return nil }
         let messageObject = queriedObjects.lastObject()
 
         if let message = messageObject as? NCChatMessage {
-            guard let filePath = message.file().path else {
-                return self.getPreviousFileMessage(from: message)
-            }
-
-            let fileType = message.file()?.mimetype ?? ""
-            let isSupportedMedia = NCUtils.isImage(fileType: fileType) || NCUtils.isVideo(fileType: fileType)
-            let isUnsupportedExtension = VLCKitVideoViewController.supportedFileExtensions.contains(URL(fileURLWithPath: filePath).pathExtension.lowercased())
-
-            if isSupportedMedia && !isUnsupportedExtension {
+            if Self.canShowMedia(of: message) {
                 return message
             }
 
@@ -189,20 +224,16 @@ import UIKit
     }
 
     func getNextFileMessage(from message: NCChatMessage) -> NCChatMessage? {
+        if let messageSource {
+            return messageSource.mediaViewerMessage(after: message)
+        }
+
         let prevQuery = NSPredicate(format: "messageId > %ld", message.messageId)
 
         guard let messageObject = self.getAllFileMessages()?.objects(with: prevQuery).firstObject() else { return nil }
 
         if let message = messageObject as? NCChatMessage {
-            guard let filePath = message.file().path else {
-                return self.getNextFileMessage(from: message)
-            }
-
-            let fileType = message.file()?.mimetype ?? ""
-            let isSupportedMedia = NCUtils.isImage(fileType: fileType) || NCUtils.isVideo(fileType: fileType)
-            let isUnsupportedExtension = VLCKitVideoViewController.supportedFileExtensions.contains(URL(fileURLWithPath: filePath).pathExtension.lowercased())
-
-            if isSupportedMedia && !isUnsupportedExtension {
+            if Self.canShowMedia(of: message) {
                 return message
             }
 
@@ -232,7 +263,17 @@ import UIKit
         return mediaPageViewController
     }
 
+    func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) {
+        self.isTransitioning = true
+    }
+
     func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
+        self.isTransitioning = false
+
+        if self.needsAdjacentPagesReload {
+            self.reloadAdjacentPages()
+        }
+
         // Update the titel of the currently shown viewController
         guard let mediaPageViewController = self.getCurrentPageViewController() else { return }
         self.navigationItem.title = mediaPageViewController.navigationItem.title