Reinitialize videos if they enter an error state

This is a palliative fix for an issue where videos become unplayable
after a long user session.

The fix works by detecting the error state anytime the video gets
played, and reinitializes the video and corresponding player views in
order to clear the error.

Changelog-Fixed: Fixed issue where some videos would become unplayable after some time using the app
Closes: https://github.com/damus-io/damus/issues/2878
Signed-off-by: Daniel D’Aquino <daniel@daquino.me>

damus/Views/Video/DamusVideoPlayer.swift

@@ -25,10 +25,14 @@ import SwiftUI
     
     /// The URL of the video
     let url: URL
+    
+    
+    // MARK: Internal state
+    
     /// The underlying AVPlayer that we are wrapping.
     /// This is not public because we don't want any callers of this class controlling the `AVPlayer` directly, we want them to go through our interface
     /// This measure helps avoid state inconsistencies and other flakiness. DO NOT USE THIS OUTSIDE `DamusVideoPlayer`
-    private let player: AVPlayer
+    private var player: AVPlayer
     
     
     // MARK: SwiftUI-friendly interface
@@ -100,16 +104,39 @@ import SwiftUI
     private var videoIsPlayingObserver: NSKeyValueObservation?
     
     
-    // MARK: - Initialization
+    // MARK: - Initialization, deinitialization and reinitialization
     
     public init(url: URL) {
         self.url = url
         self.player = AVPlayer(playerItem: AVPlayerItem(url: url))
         self.video_size = nil
         
+        Task { await self.load() }
+    }
+    
+    func reinitializePlayer() {
+        Log.info("DamusVideoPlayer: Reinitializing internal player…", for: .video_coordination)
+        
+        // Tear down
+        videoSizeObserver?.invalidate()
+        videoDurationObserver?.invalidate()
+        videoIsPlayingObserver?.invalidate()
+        
+        // Reset player
+        self.player = AVPlayer(playerItem: AVPlayerItem(url: url))
+        
+        // Load once again
         Task {
             await load()
         }
+    }
+    
+    /// Internally loads this class
+    private func load() async {
+        Task {
+            has_audio = await self.video_has_audio()
+            is_loading = false
+        }
         
         player.isMuted = is_muted
         
@@ -126,6 +153,13 @@ import SwiftUI
         observeVideoIsPlaying()
     }
     
+    deinit {
+        // These cannot be moved into their own functions due to contraints on structured concurrency
+        videoSizeObserver?.invalidate()
+        videoDurationObserver?.invalidate()
+        videoIsPlayingObserver?.invalidate()
+    }
+    
     // MARK: - Observers
     // Functions that allow us to observe certain variables and publish their changes for view updates
     // These are all private because they are part of the internal logic
@@ -175,11 +209,6 @@ import SwiftUI
     
     // MARK: - Other internal logic functions
     
-    private func load() async {
-        has_audio = await self.video_has_audio()
-        is_loading = false
-    }
-    
     private func video_has_audio() async -> Bool {
         do {
             let hasAudibleTracks = ((try await player.currentItem?.asset.loadMediaSelectionGroup(for: .audible)) != nil)
@@ -196,17 +225,16 @@ import SwiftUI
         player.play()
     }
     
-    // MARK: - Deinit
-    
-    deinit {
-        videoSizeObserver?.invalidate()
-        videoDurationObserver?.invalidate()
-        videoIsPlayingObserver?.invalidate()
-    }
-    
     // MARK: - Convenience interface functions
     
     func play() {
+        switch self.player.status {
+        case .failed:
+            Log.error("DamusVideoPlayer: Failed to play video. Error: '%s'", for: .video_coordination, self.player.error?.localizedDescription ?? "no error")
+            self.reinitializePlayer()
+        default:
+            break
+        }
         self.is_playing = true
     }
     
@@ -236,9 +264,9 @@ extension DamusVideoPlayer {
         }
         
         func updateUIViewController(_ uiViewController: AVPlayerViewController, context: Context) {
-            if uiViewController.player == nil {
+            /// - If `player.player` is changed (e.g. `DamusVideoPlayer` gets reinitialized), this will refresh the video player to the new working one.
-                uiViewController.player = player.player
+            /// - If `player.player` is unchanged, this is basically a very low cost no-op (Because `AVPlayer` is a class type, this assignment only copies a pointer, not a large structure)
-            }
+            uiViewController.player = player.player
         }
         
         static func dismantleUIViewController(_ uiViewController: AVPlayerViewController, coordinator: ()) {