Fix RuntimeBinderException, add session cleanup, memory stats endpoint, and fix all warnings

- Fixed RuntimeBinderException when comparing JsonElement with null
- Added HasValue() helper method for safe dynamic type checking
- Implemented intelligent session cleanup:
  * 50 seconds after playback stops (allows song changes)
  * 3 minutes of total inactivity (catches crashed clients)
- Added memory stats endpoint: GET /api/admin/memory-stats
- Added sessions monitoring endpoint: GET /api/admin/sessions
- Added GetSessionsInfo() to JellyfinSessionManager for debugging
- Fixed all nullable reference warnings
- Reduced warnings from 10 to 0

allstarr/Controllers/AdminController.cs

@@ -82,6 +82,17 @@ public class AdminController : ControllerBase
         _logger.LogInformation("Admin controller initialized. .env path: {EnvFilePath}", _envFilePath);
     }
     
+    /// <summary>
+    /// Helper method to safely check if a dynamic cache result has a value
+    /// Handles the case where JsonElement cannot be compared to null directly
+    /// </summary>
+    private static bool HasValue(dynamic? obj)
+    {
+        if (obj == null) return false;
+        if (obj is JsonElement jsonEl) return jsonEl.ValueKind != JsonValueKind.Null;
+        return true;
+    }
+    
     /// <summary>
     /// Get current system status and configuration
     /// </summary>
@@ -522,12 +533,12 @@ public class AdminController : ControllerBase
                                 var externalMappingKey = $"spotify:external-map:{decodedName}:{track.SpotifyId}";
                                 var externalMapping = await _cache.GetAsync<dynamic>(externalMappingKey);
                                 
-                                if (externalMapping != null)
+                                if (HasValue(externalMapping))
                                 {
                                     try
                                     {
-                                        var provider = externalMapping.provider?.ToString();
+                                        var provider = externalMapping?.provider?.ToString();
-                                        var externalId = externalMapping.id?.ToString();
+                                        var externalId = externalMapping?.id?.ToString();
                                         
                                         if (!string.IsNullOrEmpty(provider) && !string.IsNullOrEmpty(externalId))
                                         {
@@ -535,7 +546,7 @@ public class AdminController : ControllerBase
                                             isLocal = false;
                                             externalProvider = provider;
                                             _logger.LogDebug("✓ Manual external mapping found for {Title}: {Provider} {ExternalId}", 
-                                                track.Title, (object)provider, (object)externalId);
+                                                track.Title, (object?)provider, (object?)externalId);
                                         }
                                     }
                                     catch (Exception ex)
@@ -646,11 +657,11 @@ public class AdminController : ControllerBase
                 var externalMappingKey = $"spotify:external-map:{decodedName}:{track.SpotifyId}";
                 var externalMapping = await _cache.GetAsync<dynamic>(externalMappingKey);
                 
-                if (externalMapping != null)
+                if (HasValue(externalMapping))
                 {
                     try
                     {
-                        var provider = externalMapping.provider?.ToString();
+                        var provider = externalMapping?.provider?.ToString();
                         if (!string.IsNullOrEmpty(provider))
                         {
                             isLocal = false;
@@ -2137,6 +2148,29 @@ public class AdminController : ControllerBase
         }
     }
 
+    /// <summary>
+    /// Gets current active sessions for debugging.
+    /// </summary>
+    [HttpGet("sessions")]
+    public IActionResult GetActiveSessions()
+    {
+        try
+        {
+            var sessionManager = HttpContext.RequestServices.GetService<JellyfinSessionManager>();
+            if (sessionManager == null)
+            {
+                return BadRequest(new { error = "Session manager not available" });
+            }
+
+            var sessionInfo = sessionManager.GetSessionsInfo();
+            return Ok(sessionInfo);
+        }
+        catch (Exception ex)
+        {
+            return BadRequest(new { error = ex.Message });
+        }
+    }
+
     /// <summary>
     /// Helper method to trigger GC after large file operations to prevent memory leaks.
     /// </summary>

allstarr/Controllers/JellyfinController.cs

@@ -2217,6 +2217,7 @@ public class JellyfinController : ControllerBase
             string? itemId = null;
             string? itemName = null;
             long? positionTicks = null;
+            string? deviceId = null;
             
             if (doc.RootElement.TryGetProperty("ItemId", out var itemIdProp))
             {
@@ -2233,6 +2234,12 @@ public class JellyfinController : ControllerBase
                 positionTicks = posProp.GetInt64();
             }
 
+            // Try to get device ID from headers for session management
+            if (Request.Headers.TryGetValue("X-Emby-Device-Id", out var deviceIdHeader))
+            {
+                deviceId = deviceIdHeader.FirstOrDefault();
+            }
+
             if (!string.IsNullOrEmpty(itemId))
             {
                 var (isExternal, provider, externalId) = _localLibraryService.ParseSongId(itemId);
@@ -2244,6 +2251,14 @@ public class JellyfinController : ControllerBase
                         : "unknown";
                     _logger.LogInformation("🎵 External track playback stopped: {Name} at {Position} ({Provider}/{ExternalId})", 
                         itemName ?? "Unknown", position, provider, externalId);
+                    
+                    // Mark session as potentially ended after playback stops
+                    // Wait 50 seconds for next song to start before cleaning up
+                    if (!string.IsNullOrEmpty(deviceId))
+                    {
+                        _sessionManager.MarkSessionPotentiallyEnded(deviceId, TimeSpan.FromSeconds(50));
+                    }
+                    
                     return NoContent();
                 }
                 

allstarr/Services/Jellyfin/JellyfinSessionManager.cs

@@ -143,6 +143,64 @@ public class JellyfinSessionManager : IDisposable
         }
     }
 
+    /// <summary>
+    /// Marks a session as potentially ended (e.g., after playback stops).
+    /// The session will be cleaned up if no new activity occurs within the timeout.
+    /// </summary>
+    public void MarkSessionPotentiallyEnded(string deviceId, TimeSpan timeout)
+    {
+        if (_sessions.TryGetValue(deviceId, out var session))
+        {
+            _logger.LogDebug("⏰ SESSION: Marking session {DeviceId} as potentially ended, will cleanup in {Seconds}s if no activity", 
+                deviceId, timeout.TotalSeconds);
+            
+            _ = Task.Run(async () =>
+            {
+                var markedTime = DateTime.UtcNow;
+                await Task.Delay(timeout);
+                
+                // Check if there's been activity since we marked it
+                if (_sessions.TryGetValue(deviceId, out var currentSession) && 
+                    currentSession.LastActivity <= markedTime)
+                {
+                    _logger.LogInformation("🧹 SESSION: Auto-removing inactive session {DeviceId} after playback stop", deviceId);
+                    await RemoveSessionAsync(deviceId);
+                }
+                else
+                {
+                    _logger.LogDebug("✓ SESSION: Session {DeviceId} had activity, keeping alive", deviceId);
+                }
+            });
+        }
+    }
+
+    /// <summary>
+    /// Gets information about current active sessions for debugging.
+    /// </summary>
+    public object GetSessionsInfo()
+    {
+        var now = DateTime.UtcNow;
+        var sessions = _sessions.Values.Select(s => new
+        {
+            DeviceId = s.DeviceId,
+            Client = s.Client,
+            Device = s.Device,
+            Version = s.Version,
+            LastActivity = s.LastActivity,
+            InactiveMinutes = Math.Round((now - s.LastActivity).TotalMinutes, 1),
+            HasWebSocket = s.WebSocket != null,
+            WebSocketState = s.WebSocket?.State.ToString() ?? "None"
+        }).ToList();
+
+        return new
+        {
+            TotalSessions = sessions.Count,
+            ActiveSessions = sessions.Count(s => s.InactiveMinutes < 2),
+            StaleSessions = sessions.Count(s => s.InactiveMinutes >= 2),
+            Sessions = sessions.OrderBy(s => s.InactiveMinutes)
+        };
+    }
+
     /// <summary>
     /// Removes a session when the client disconnects.
     /// </summary>
@@ -408,12 +466,14 @@ public class JellyfinSessionManager : IDisposable
             }
         }
 
-        // Clean up stale sessions (inactive for > 10 minutes)
+        // Clean up stale sessions after 3 minutes of inactivity
-        var staleSessions = _sessions.Where(kvp => now - kvp.Value.LastActivity > TimeSpan.FromMinutes(10)).ToList();
+        // This balances cleaning up finished sessions with allowing brief pauses/network issues
+        var staleSessions = _sessions.Where(kvp => now - kvp.Value.LastActivity > TimeSpan.FromMinutes(3)).ToList();
         foreach (var stale in staleSessions)
         {
-            _logger.LogInformation("🧹 SESSION: Removing stale session for {DeviceId}", stale.Key);
+            _logger.LogInformation("🧹 SESSION: Removing stale session for {DeviceId} (inactive for {Minutes:F1} minutes)", 
-            _sessions.TryRemove(stale.Key, out _);
+                stale.Key, (now - stale.Value.LastActivity).TotalMinutes);
+            await RemoveSessionAsync(stale.Key);
         }
     }
 

allstarr/Services/MusicBrainz/MusicBrainzService.cs

@@ -77,7 +77,7 @@ public class MusicBrainzService
 
             // Return the first recording (ISRCs should be unique)
             var recording = result.Recordings[0];
-            var genres = recording.Genres?.Select(g => g.Name).Where(n => !string.IsNullOrEmpty(n)).ToList() ?? new List<string>();
+            var genres = recording.Genres?.Select(g => g.Name).Where(n => !string.IsNullOrEmpty(n)).ToList() ?? new List<string?>();
             _logger.LogInformation("✓ Found MusicBrainz recording for ISRC {Isrc}: {Title} by {Artist} (Genres: {Genres})",
                 isrc, recording.Title, recording.ArtistCredit?[0]?.Name ?? "Unknown", string.Join(", ", genres));
 

allstarr/Services/Spotify/SpotifyTrackMatchingService.cs

@@ -41,6 +41,17 @@ public class SpotifyTrackMatchingService : BackgroundService
         _serviceProvider = serviceProvider;
         _logger = logger;
     }
+    
+    /// <summary>
+    /// Helper method to safely check if a dynamic cache result has a value
+    /// Handles the case where JsonElement cannot be compared to null directly
+    /// </summary>
+    private static bool HasValue(dynamic? obj)
+    {
+        if (obj == null) return false;
+        if (obj is JsonElement jsonEl) return jsonEl.ValueKind != JsonValueKind.Null;
+        return true;
+    }
 
     protected override async Task ExecuteAsync(CancellationToken stoppingToken)
     {
@@ -318,7 +329,7 @@ public class SpotifyTrackMatchingService : BackgroundService
             // Also check for external manual mappings
             var externalMappingKey = $"spotify:external-map:{playlistName}:{track.SpotifyId}";
             var externalMapping = await _cache.GetAsync<dynamic>(externalMappingKey);
-            if (externalMapping != null)
+            if (HasValue(externalMapping))
             {
                 hasManualMappings = true;
                 break;
@@ -822,12 +833,12 @@ public class SpotifyTrackMatchingService : BackgroundService
                     var externalMappingKey = $"spotify:external-map:{playlistName}:{spotifyTrack.SpotifyId}";
                     var externalMapping = await _cache.GetAsync<dynamic>(externalMappingKey);
                     
-                    if (externalMapping != null)
+                    if (HasValue(externalMapping))
                     {
                         try
                         {
-                            var provider = externalMapping.provider?.ToString();
+                            var provider = externalMapping?.provider?.ToString();
-                            var externalId = externalMapping.id?.ToString();
+                            var externalId = externalMapping?.id?.ToString();
                             
                             if (!string.IsNullOrEmpty(provider) && !string.IsNullOrEmpty(externalId))
                             {
@@ -852,7 +863,7 @@ public class SpotifyTrackMatchingService : BackgroundService
                                 });
                                 
                                 _logger.LogInformation("✓ Using manual external mapping for {Title}: {Provider} {ExternalId}", 
-                                    spotifyTrack.Title, (object)provider, (object)externalId);
+                                    spotifyTrack.Title, (object?)provider, (object?)externalId);
                                 continue; // Skip to next track
                             }
                         }