forward late subtitles to native player

Dreamio/DreamioWebViewController.swift

@@ -6,6 +6,7 @@ final class DreamioWebViewController: UIViewController {
         static let stremioWebURL = URL(string: "https://web.stremio.com/")!
         static let diagnosticsMessageHandler = "dreamioDiagnostics"
         static let streamCandidateMessageHandler = "dreamioStreamCandidate"
+        static let subtitleCandidateMessageHandler = "dreamioSubtitleCandidate"
     }
 
     private lazy var webView: WKWebView = {
@@ -18,6 +19,10 @@ final class DreamioWebViewController: UIViewController {
             WeakScriptMessageHandler(delegate: self),
             name: Constants.streamCandidateMessageHandler
         )
+        configuration.userContentController.add(
+            WeakScriptMessageHandler(delegate: self),
+            name: Constants.subtitleCandidateMessageHandler
+        )
         configuration.userContentController.addUserScript(Self.streamCandidateScript)
 #if DEBUG
         configuration.userContentController.add(
@@ -52,6 +57,7 @@ final class DreamioWebViewController: UIViewController {
     private var progressObservation: NSKeyValueObservation?
     private var userAgent: String?
     private var lastNativePlaybackURL: URL?
+    private weak var currentNativePlayer: NativePlayerViewController?
     private let streamResolver: StreamResolving = StremioStreamResolver()
 
     private static let streamCandidateScript = WKUserScript(
@@ -73,6 +79,7 @@ final class DreamioWebViewController: UIViewController {
             /\.mp4(?:[?#]|$)/i
           ];
           const subtitleCandidates = [];
+          const postedSubtitleURLs = new Set();
           const subtitleURLPattern = /https?:\/\/[^\s"'<>]+(?:\.srt|\.vtt|\.ass|\.ssa|\.sub|opensubtitles|subtitle)[^\s"'<>]*/ig;
 
           const looksNative = (url) => {
@@ -119,6 +126,25 @@ final class DreamioWebViewController: UIViewController {
             } catch (_) {}
           };
 
+          const postSubtitleCandidates = (candidates) => {
+            const fresh = candidates.filter((candidate) => {
+              if (postedSubtitleURLs.has(candidate.url)) {
+                return false;
+              }
+              postedSubtitleURLs.add(candidate.url);
+              return true;
+            });
+            if (fresh.length === 0) {
+              return;
+            }
+            try {
+              window.webkit.messageHandlers.dreamioSubtitleCandidate.postMessage({
+                pageUrl: window.location.href,
+                subtitles: fresh
+              });
+            } catch (_) {}
+          };
+
           const addSubtitleCandidate = (entry) => {
             const rawURL = typeof entry === "string" ? entry : entry && (entry.url || entry.href || entry.src || entry.file || entry.download);
             const url = absoluteURL(rawURL);
@@ -131,11 +157,13 @@ final class DreamioWebViewController: UIViewController {
             if (subtitleCandidates.some((candidate) => candidate.url === url)) {
               return;
             }
-            subtitleCandidates.push({
+            const candidate = {
               url,
               label: entry && (entry.label || entry.name || entry.title || entry.lang || entry.language) || "External Subtitle",
               language: entry && (entry.lang || entry.language) || ""
-            });
+            };
+            subtitleCandidates.push(candidate);
+            postSubtitleCandidates([candidate]);
           };
 
           const inspectSubtitlePayload = (payload) => {
@@ -422,7 +450,7 @@ final class DreamioWebViewController: UIViewController {
 
 #if DEBUG
         let classification = request.classification
-        print("[DreamioStream] class=\(classification.sourceKind.rawValue) container=\(classification.containerGuess.rawValue) reason=\(classification.reason) observed=\(classification.sanitizedObservedURL) resolver=\(classification.sanitizedResolverURL ?? "none")")
+        print("[DreamioStream] class=\(classification.sourceKind.rawValue) container=\(classification.containerGuess.rawValue) reason=\(classification.reason) subtitles=\(request.subtitleCandidates.count) observed=\(classification.sanitizedObservedURL) resolver=\(classification.sanitizedResolverURL ?? "none")")
 #endif
 
         Task { [weak self] in
@@ -430,6 +458,24 @@ final class DreamioWebViewController: UIViewController {
         }
     }
 
+    private func handleSubtitleCandidates(_ candidates: [SubtitleCandidate]) {
+        guard !candidates.isEmpty else {
+            return
+        }
+
+        guard let currentNativePlayer else {
+#if DEBUG
+            print("[DreamioSubtitles] discovered=\(candidates.count) forwarded=0 reason=no-active-native-player")
+#endif
+            return
+        }
+
+        let forwarded = currentNativePlayer.addSubtitleCandidates(candidates)
+#if DEBUG
+        print("[DreamioSubtitles] discovered=\(candidates.count) forwarded=\(forwarded)")
+#endif
+    }
+
     @MainActor
     private func resolveAndPresentNativePlayback(_ request: NativePlaybackRequest) async {
         guard VLCNativePlaybackBackend.isAvailable else {
@@ -455,8 +501,10 @@ final class DreamioWebViewController: UIViewController {
                 subtitleCandidates: request.subtitleCandidates
             )
             let player = NativePlayerViewController(request: resolvedRequest)
+            currentNativePlayer = player
             player.onDismiss = { [weak self] in
                 self?.lastNativePlaybackURL = nil
+                self?.currentNativePlayer = nil
                 self?.cleanUpStremioPlayerAfterNativeDismiss()
             }
             present(player, animated: true)
@@ -669,6 +717,11 @@ extension DreamioWebViewController: WKScriptMessageHandler {
             return
         }
 
+        if message.name == Constants.subtitleCandidateMessageHandler {
+            handleSubtitleCandidates(SubtitleCandidateParser.candidates(in: message.body))
+            return
+        }
+
 #if DEBUG
         guard message.name == Constants.diagnosticsMessageHandler,
               let body = message.body as? [String: Any],

Dreamio/NativePlaybackBackend.swift

@@ -25,6 +25,8 @@ protocol NativePlaybackBackend: AnyObject {
     func jump(by seconds: TimeInterval)
     func selectSubtitleTrack(id: Int32)
     func adjustSubtitleDelay(by seconds: TimeInterval)
+    @discardableResult
+    func addSubtitleCandidates(_ candidates: [SubtitleCandidate]) -> Int
     func stop()
 }
 

Dreamio/NativePlayerViewController.swift

@@ -7,6 +7,7 @@ final class NativePlayerViewController: UIViewController {
     private var controlsTimer: Timer?
     private var progressTimer: Timer?
     private var isScrubbing = false
+    private var attachedSubtitleURLs: Set<URL>
     var onDismiss: (() -> Void)?
 
     private let loadingView: UIActivityIndicatorView = {
@@ -94,6 +95,7 @@ final class NativePlayerViewController: UIViewController {
     init(request: NativePlaybackRequest, backend: NativePlaybackBackend = VLCNativePlaybackBackend()) {
         self.request = request
         self.backend = backend
+        self.attachedSubtitleURLs = Set(request.subtitleCandidates.map(\.url))
         super.init(nibName: nil, bundle: nil)
         modalPresentationStyle = .fullScreen
         modalTransitionStyle = .crossDissolve
@@ -126,6 +128,26 @@ final class NativePlayerViewController: UIViewController {
         backend.play(request: request)
     }
 
+    @discardableResult
+    func addSubtitleCandidates(_ candidates: [SubtitleCandidate]) -> Int {
+        let newCandidates = candidates.filter { candidate in
+            guard !attachedSubtitleURLs.contains(candidate.url) else {
+                return false
+            }
+            attachedSubtitleURLs.insert(candidate.url)
+            return true
+        }
+        let attachedCount = backend.addSubtitleCandidates(newCandidates)
+        if attachedCount > 0 {
+            refreshControls()
+        }
+#if DEBUG
+        let duplicateCount = candidates.count - newCandidates.count
+        print("[DreamioNativePlayer] subtitle candidates=\(candidates.count) forwarded=\(newCandidates.count) attached=\(attachedCount) duplicates=\(duplicateCount)")
+#endif
+        return attachedCount
+    }
+
     override func viewDidDisappear(_ animated: Bool) {
         super.viewDidDisappear(animated)
         startupTimer?.invalidate()

Dreamio/VLCNativePlaybackBackend.swift

@@ -58,7 +58,7 @@ final class VLCNativePlaybackBackend: NSObject, NativePlaybackBackend {
         print("[DreamioVLC] opening url=\(URLRedactor.redactedURLString(request.playbackURL.absoluteString))")
 #endif
         mediaPlayer.play()
-        attachSubtitles(request.subtitleCandidates)
+        addSubtitleCandidates(request.subtitleCandidates)
 #else
         onFailure?(NativePlaybackError.backendUnavailable)
 #endif
@@ -113,6 +113,15 @@ final class VLCNativePlaybackBackend: NSObject, NativePlaybackBackend {
 #endif
     }
 
+    @discardableResult
+    func addSubtitleCandidates(_ candidates: [SubtitleCandidate]) -> Int {
+#if canImport(MobileVLCKit)
+        return attachSubtitles(candidates)
+#else
+        return 0
+#endif
+    }
+
     func stop() {
 #if canImport(MobileVLCKit)
         mediaPlayer.stop()
@@ -194,23 +203,33 @@ final class VLCNativePlaybackBackend: NSObject, NativePlaybackBackend {
     }
 
 #if canImport(MobileVLCKit)
-    private func attachSubtitles(_ candidates: [SubtitleCandidate]) {
+    private func attachSubtitles(_ candidates: [SubtitleCandidate]) -> Int {
+        var attachedCount = 0
+        var duplicateCount = 0
         candidates.forEach { candidate in
             guard !attachedSubtitleURLs.contains(candidate.url) else {
+                duplicateCount += 1
                 return
             }
             attachedSubtitleURLs.insert(candidate.url)
             mediaPlayer.addPlaybackSlave(candidate.url, type: .subtitle, enforce: false)
+            attachedCount += 1
 #if DEBUG
             print("[DreamioVLC] attached subtitle=\(URLRedactor.redactedURLString(candidate.url.absoluteString))")
 #endif
         }
-        guard !candidates.isEmpty else {
-            return
+#if DEBUG
+        if !candidates.isEmpty {
+            print("[DreamioVLC] subtitle candidates=\(candidates.count) attached=\(attachedCount) duplicates=\(duplicateCount)")
+        }
+#endif
+        guard attachedCount > 0 else {
+            return attachedCount
         }
         DispatchQueue.main.asyncAfter(deadline: .now() + 1) { [weak self] in
             self?.onSubtitleTracksChange?()
         }
+        return attachedCount
     }
 #endif
 }