Radio in NullPlayer

NullPlayer has two distinct radio systems:

1. Internet Radio — Shoutcast/Icecast stream playback (via RadioManager)
2. Library Radio — Smart playlist generation from Subsonic, Jellyfin, Emby, Plex, and local files, with play-history filtering

---

1. Internet Radio

Architecture

Sources/NullPlayer/
├── Radio/
│   ├── RadioManager.swift             # Singleton managing internet radio state
│   ├── RadioStationRatingsStore.swift # SQLite-backed 0-5 ratings (URL-keyed)
│   ├── RadioFolderModels.swift        # Folder descriptor/kind model
│   └── RadioStationFoldersStore.swift # SQLite-backed folders + memberships + play history
├── Resources/Radio/
│   └── default_stations.json          # Bundled default station catalog
├── Data/Models/
│   └── RadioStation.swift             # Station data model
├── Windows/Radio/
│   └── AddRadioStationSheet.swift     # Add/edit station UI
├── Windows/ModernLibraryBrowser/
│   └── ModernLibraryBrowserView.swift # Internet radio folder tree + rating column
└── Windows/PlexBrowser/
    └── PlexBrowserView.swift          # Internet radio folder tree + rating column

RadioManager

Singleton (RadioManager.shared) that manages:

• Station list (seeded from bundled JSON, persisted to UserDefaults)
• Current playing station
• Connection state (disconnected/connecting/connected/reconnecting/failed)
• Stream metadata (ICY + SomaFM fallback)
• Internet-radio-only station ratings and folder organization
• Auto-reconnect logic

Key Properties:

var stations: [RadioStation]           // All saved stations
var currentStation: RadioStation?      // Currently playing (nil if not radio)
var currentStreamTitle: String?        // ICY metadata "Artist - Song"
var currentSomaLastPlaying: String?    // SomaFM fallback metadata
var connectionState: ConnectionState   // Current connection state
var isActive: Bool                      // True if radio is playing
var statusText: String?                 // Marquee text (effective stream title)

Notifications:

• stationsDidChangeNotification — Station list modified
• streamMetadataDidChangeNotification — effective stream metadata changed (ICY first, Soma fallback second)
• connectionStateDidChangeNotification — Connection state changed

RadioStation Model

struct RadioStation: Identifiable, Codable {
    let id: UUID
    var name: String
    var url: URL
    var genre: String?
    var iconURL: URL?

    func toTrack() -> Track  // Convert to playable Track
}

Connection States

enum ConnectionState {
    case disconnected           // Not playing radio
    case connecting             // Initial connection attempt
    case connected              // Successfully streaming
    case reconnecting(attempt)  // Auto-reconnect in progress
    case failed(message)        // Connection failed
}

Audio Engine Integration

RadioManager integrates with AudioEngine through delegate callbacks:

Callback	Purpose
streamDidConnect()	Called when stream starts playing
streamDidDisconnect(error:)	Called on stream end/error, triggers reconnect
streamDidReceiveMetadata(_:)	Receives ICY metadata for display

Critical: State Preservation

When loadTracks() is called with radio content:

1. Detect radio content by comparing track.url with currentStation.url
2. Use stopLocalOnly() instead of stop() to preserve RadioManager state
3. Calling stop() would trigger RadioManager.stop(), clearing state

let isRadioContent: Bool
if RadioManager.shared.isActive {
    isRadioContent = validTracks.first.map { track in
        RadioManager.shared.currentStation?.url == track.url
    } ?? false
}
// Use stopLocalOnly() for radio, stop() for other content
if isRadioContent { stopLocalOnly() } else { stop() }

Playlist URL Resolution

Radio stations often use .pls/.m3u/.m3u8 playlist URLs. Always check CastManager.shared.isCasting fresh inside the async callback — resolution can take up to 10 seconds.

Auto-Reconnect

1. streamDidDisconnect(error:) fires
2. If manualStopRequested == false and autoReconnectEnabled == true: exponential backoff (2s, 4s, 8s, 16s, 32s), max 5 attempts
3. After max attempts → .failed

Manual stop (user pressing Stop, loading non-radio content, switching stations) sets manualStopRequested = true and does not trigger reconnect.

Stream Metadata (ICY + Soma Fallback)

Primary path: StreamingAudioPlayer → AudioEngine → RadioManager.currentStreamTitle → streamMetadataDidChangeNotification.

Fallback path: When ICY metadata is missing for SomaFM streams, RadioManager polls https://somafm.com/channels.json and maps channel lastPlaying into currentSomaLastPlaying.

Published value is effectiveStreamTitle:

1. currentStreamTitle (ICY)
2. currentSomaLastPlaying (Soma fallback)

UI should consume only streamMetadataDidChangeNotification and not assume ICY is always present.

Casting Radio to Sonos

• Sonos receives the stream URL directly (no proxy)
• Time resets to 0:00 (live stream)
• For MP3 streams use x-rincon-mp3radio:// URI scheme (Sonos internal buffering)

Station Persistence

Internet radio persistence is split by concern:

• Bundled default catalog: Sources/NullPlayer/Resources/Radio/default_stations.json (full curated default station list shipped with the app)
• Saved station list: JSON in UserDefaults key "RadioStations" (user runtime list; initialized from bundled defaults on first launch or reset)
• Ratings: SQLite ~/Library/Application Support/NullPlayer/radio_station_ratings.db, table radio_station_ratings (station_url PK, rating 0...5, updated_at)
• Folders/memberships/play history: SQLite ~/Library/Application Support/NullPlayer/radio_station_folders.db
  • radio_folders
  • radio_station_folder_memberships (folder ↔ station URL)
  • radio_station_play_history (used for "Recently Played" smart folder)

Ratings/folders are URL-keyed. If a station URL is edited, RadioManager.updateStation migrates rating and folder references to the new URL. Removing a station purges rating + folder membership + play history rows for that URL.

Internet Radio Organization (Folders + Ratings)

Internet Radio now uses folder-tree organization in both ModernLibraryBrowserView and PlexBrowserView.

Smart folders:

• All Stations
• Favorites (rating >= 4)
• Top Rated
• Unrated
• Recently Played
• By Genre (group + dynamic children)
• By Region (group + dynamic children)

Manual folders:

• User-created folders under "My Folders"
• Station membership is managed from station context menu (Folders submenu)

Key behavior:

• Rating is 0...5 stars (0 = unrated); clicking the same star again clears rating.
• Rating column is shown for Internet Radio station rows only.
• Genre column is centered for all radio sources.
• Internet Radio context menu includes folder actions (create, rename, delete, set active, add/remove station membership).

---

3. Internet Radio Play History

Internet radio listen sessions are recorded in the shared play_events table (see local-library skill for schema). This is distinct from the per-source radio history databases used for playlist deduplication.

Session Tracking (AudioEngine)

AudioEngine maintains an activeRadioSession: RadioSession? private struct:

private struct RadioSession {
    let track: Track
    let stationURL: URL
    var startedAt: Date
    var pausedAccumulator: TimeInterval    // total paused seconds
    var lastPauseStartedAt: Date?          // non-nil while paused
}

State transitions are driven by handleRadioSessionPlaybackStateChange(from:to:) called from the state property observer:

Transition	Action
→ .playing	startOrResumeActiveRadioSessionIfNeeded()
.playing → .paused	pauseActiveRadioSessionIfNeeded() — records pause start
→ .stopped	flushActiveRadioSession() — writes event and nils session

Station switches: if the playing track's URL differs from activeRadioSession.stationURL, the old session is flushed and a new one starts.

Non-radio tracks: if the track's playHistorySource != .radio, any active session is flushed immediately.

Audibility Guard (isRadioPlaybackAudibleNow)

Sessions are only started/resumed when audio is actually being delivered. The guard checks:

• For audio casts: CastManager.shared.activeSession.playbackStartDate != nil
• For local streaming: !isStreamingPlayback || streamingPlaybackConfirmed

streamingPlaybackConfirmed is set to true when StreamingAudioPlayerDelegate fires .playing state, and reset to false when streaming starts loading a new track or enters stopped/error state. This prevents recording time during buffering.

Long-Session Checkpoints

A 30-minute checkpoint fires from the timer tick path (checkpointActiveRadioSessionIfNeeded). When listened >= 30 * 60 and not paused:

1. Writes a play event for the elapsed 30 minutes
2. Resets startedAt to now with zero pausedAccumulator

This prevents a single very long session from being lost if the app crashes before the station is stopped.

App-Quit Flush

AppDelegate.applicationWillTerminate calls audioEngine.flushActiveRadioSessionIfAny() before any other teardown. This ensures in-progress sessions are recorded even when the user quits while radio is playing.

Play Event Schema

Radio sessions write to play_events with:

Column	Value
track_id	nil
track_url	Station stream URL (absolute string)
event_title	Station name (track.title)
event_artist	nil
event_genre	Station genre if set
source	PlayHistorySource.radio.rawValue ("radio")
content_type	"radio"
duration_listened	Actual listen seconds (elapsed minus paused)
skipped	false for normal stop/switch; true if skipped
output_device	Active output or cast device name

Minimum threshold: sessions shorter than 1 second are discarded.

Data Tab — Internet Radio Section

PlayHistoryStore exposes two radio-specific queries:

• fetchTopRadioStations(filter:) — groups by station URL (uses URL as id, title as display name), returns top 50 by play count
• fetchRadioListenSeconds(filter:) — total SUM(duration_listened) for radio events

Both use whereClause(forRadio:) which respects only time range, output device, and skip filters (artist/album/genre/source/content type don't apply to radio).

PlayHistoryAgent publishes topRadioStations: [TopDimensionRow] and radioListenSeconds: Double.

InternetRadioSection in StatsContentView.swift renders the section only when !rows.isEmpty || totalSeconds > 0. It shows total formatted listen time, a "Top N stations" label, and a TopDimensionChartView with showsTotalMinutes: true (displays "plays / duration" per row).

Radio events are excluded from music/video charts: fetchTopArtists, fetchGenreBreakdown, and source/album/genre dimensions in fetchTopDimension all add COALESCE(pe.content_type, 'music') <> 'radio' conditions.

The source filter UI silently drops any selection of the radio source (selectSource(_:) in PlayHistoryAgent maps PlayHistorySource.radio.rawValue → nil), since radio is presented separately.

---

2. Library Radio

Library Radio generates smart playlists from server/local sources with play-history deduplication.

Architecture

Sources/NullPlayer/
├── Subsonic/
│   ├── SubsonicManager.swift        # createXxxRadio functions
│   └── SubsonicRadioHistory.swift   # SQLite play history
├── Jellyfin/
│   ├── JellyfinManager.swift        # createXxxRadio functions
│   └── JellyfinRadioHistory.swift   # SQLite play history
├── Emby/
│   ├── EmbyManager.swift            # createXxxRadio functions
│   └── EmbyRadioHistory.swift       # SQLite play history
├── Data/Models/
│   ├── MediaLibrary.swift           # createLocalXxxRadio functions
│   └── LocalRadioHistory.swift      # SQLite play history for local files
├── Windows/ModernLibraryBrowser/
│   └── ModernLibraryBrowserView.swift  # Radio tab UI + RadioType enums
└── Windows/PlexBrowser/
    └── PlexBrowserView.swift           # Classic/Plex browser radio tab UI + RadioType enums

Radio Types (per source)

Subsonic (SubsonicRadioType):

Case	Function	Description
.libraryRadio	createLibraryRadio()	Random songs from whole library
.librarySimilar	createLibraryRadioSimilar()	Subsonic getSimilarSongs2 from current track
.starredRadio	createRatingRadio()	Starred songs, shuffled
.starredSimilar	createRatingRadioSimilar()	Similar songs seeded from starred
.genreRadio(g)	createGenreRadio(genre:)	Songs in genre
.genreSimilar(g)	createGenreRadioSimilar(genre:)	Similar to a random track in genre
.decadeRadio(s,e,name)	createDecadeRadio(start:end:)	Songs from year range
.decadeSimilar(s,e,name)	createDecadeRadioSimilar(start:end:)	Similar to a random decade track

Jellyfin (JellyfinRadioType):

Case	Function
.libraryRadio	createLibraryRadio() — random songs
.libraryInstantMix	createLibraryRadioInstantMix() — InstantMix seeded from current track
.genreRadio(g)	createGenreRadio(genre:)
.genreInstantMix(g)	createGenreRadioInstantMix(genre:)
.decadeRadio(s,e,name)	createDecadeRadio(start:end:)
.decadeInstantMix(s,e,name)	createDecadeRadioInstantMix(start:end:)
.favoritesRadio	createFavoritesRadio() — favorite songs
.favoritesInstantMix	createFavoritesRadioInstantMix()

Emby (EmbyRadioType) — same structure as Jellyfin (Library, Genre, Decade, Favorites each with plain + InstantMix variant).

Local (LocalRadioType):

Case	Function
.libraryRadio	createLocalLibraryRadio()
.genreRadio(g)	createLocalGenreRadio(genre:)
.decadeRadio(s,e,name)	createLocalDecadeRadio(start:end:)

MediaLibrary also has createLocalArtistRadio(artist:limit:) for artist-seeded radio (prefers albumArtist over artist).

RadioConfig

RadioConfig (file: ModernLibraryBrowserView.swift) provides shared constants:

struct RadioConfig {
    static let defaultLimit = 100          // Tracks per radio session
    static let decades: [DecadeRange]      // Pre-defined decade ranges (1960s–2020s)
    static let ratingStations: [...]       // Plex rating-based presets
}

Playback Options Menu

Playback options now expose a dedicated Radio submenu.

Items under Playback Options -> Radio:

• Max Tracks Per Artist
• Playlist Length
• History

Playlist Length is backed by RadioPlaybackOptions.playlistLength and supports:

• 100
• 250
• 500
• 1000
• 10000

Max Tracks Per Artist and radio history controls were moved under this submenu from the top-level playback options menu.

Playlist Generation Pipeline

Each createXxxRadio function follows this pattern:

1. Fetch candidate tracks from server
2. filterOutHistoryTracks(_:)  — remove recently played
3. filterForArtistVariety(_:limit:maxPerArtist:)  — cap per-artist slots
4. Return up to `limit` tracks

Candidate fetch sizing:

• Standard behavior: over-fetch by 3x for headroom before artist dedupe
• If Max Tracks Per Artist is Unlimited (0), use the requested playlist length directly and do not over-fetch

Instant Mix / Similar functions additionally:

1. Try to reuse the currently playing track as seed (if it belongs to the active server)
2. Fall back to fetching a random seed from the server
3. Call server's InstantMix/getSimilarSongs2 API with the seed

Play History System

Each source has its own SQLite database in ~/Library/Application Support/NullPlayer/:

Source	Database	Class
Subsonic	subsonic_radio_history.db	SubsonicRadioHistory
Jellyfin	jellyfin_radio_history.db	JellyfinRadioHistory
Emby	emby_radio_history.db	EmbyRadioHistory
Local	local_radio_history.db	LocalRadioHistory

Schema (Subsonic/Jellyfin/Emby): id, track_id, title, artist, album, server_id, played_at (epoch Double), normalized_key

Schema (Local): id, track_url, title, artist, album, played_at, normalized_key

Key methods:

func recordTrackPlayed(_ track: Track)           // Insert/replace on track finish
func filterOutHistoryTracks(_ tracks: [Track]) -> [Track]  // Remove recently played
func fetchHistory() -> [XxxRadioHistoryEntry]    // For history page
func clearHistory()                              // Wipe database
var isEnabled: Bool                              // retentionInterval != .off
var historyPageURL: URL?                         // http://127.0.0.1:{httpPort}/xxx-radio-history

Retention intervals: Off / 2 Weeks / 1 Month (default) / 3 Months / 6 Months. Stored in UserDefaults (e.g. "subsonicRadioHistoryInterval").

Dedup logic: Tracks are excluded if their track_id OR normalized_key ("artist|title", lowercased) appears in history within the retention window for the active server (server_id == currentServer.id).

Thread safety: recordTrackPlayed is always called via Task.detached(priority: .utility) in AudioEngine (4 call sites: cast completion, local completion, crossfade, streaming crossfade) to keep SQLite I/O off the audio callback thread.

History Web Pages

LocalMediaServer (port: LocalMediaServer.httpPort = 8765) serves per-source history pages:

URL	Source
/subsonic-radio-history	Subsonic
/jellyfin-radio-history	Jellyfin
/emby-radio-history	Emby
/local-radio-history	Local files

Pages are generated as self-contained HTML with a sortable table. The Played column uses data-sort="{epoch}" for correct numeric sort (not locale string sort).

Accessed via context menu: right-click → Options → Radio History → source-specific entry.

The context menu entry is shown whenever a server has ever been configured (not only while actively connected).

If LocalMediaServer.start() fails, an NSAlert is shown describing the error (not silently swallowed).

Artist Variety Filtering

After history filtering, filterForArtistVariety caps tracks per artist:

func filterForArtistVariety(_ tracks: [Track], limit: Int, maxPerArtist: Int = 2) -> [Track]

Standard radio: maxPerArtist = 2. Instant Mix / Similar: maxPerArtist = 1 (more variety).

Race Condition Guards (ModernLibraryBrowserView)

• radioLoadTask: cancelled when source/mode changes before a new genre fetch begins. Result is discarded if source or browseMode changed while awaiting.
• radioPlayTask: cancelled if user double-clicks another station before the previous radio generation completes.

---

UI Integration

Library Browser Radio Tab

The browser Radio tab has two behaviors:

• Internet Radio source (currentSource == .radio):
  • Folder tree + active-folder station list
  • Columns: Title | Genre | Rating for station rows
  • Genre centered; rating centered
  • Folder context actions + station folder-membership submenu
• Library radio sources (Plex/Subsonic/Jellyfin/Emby/Local):
  • Source-specific generated radio stations (Library/Genre/Decade/etc.)
  • Genre/category column centered in radio lists
  • Double-click to generate and play queue

Implemented in both browser views:

• Windows/ModernLibraryBrowser/ModernLibraryBrowserView.swift
• Windows/PlexBrowser/PlexBrowserView.swift

Main Window Marquee

Priority order:

1. Error message
2. Video title (video playing)
3. Radio status/stream title (internet radio active)
4. Track title

---

Testing Checklist

Internet radio:

• Add station with direct stream URL and with .pls/.m3u URL
• Add a cleartext http:// station (e.g. Icecast on a custom port) → it actually plays, not just buffers forever (ATS regression guard, #255 / #310 — no CFNetwork -1022; clock advances past 0:00)
• Metadata displays in marquee (ICY when present, Soma fallback when ICY absent)
• Stop → no auto-reconnect; disconnect network → auto-reconnect attempts
• Cast to Sonos, time resets to 0:00
• Folder tree renders in both Modern and Plex browsers
• Create/rename/delete manual folder; station membership toggles correctly
• Rating stars persist across relaunch; clicking selected star clears rating
• Editing station URL migrates rating/folder membership

Library radio:

• Subsonic/Jellyfin/Emby radio tab loads genres and decade stations
• Double-click station → playlist fills with correct tracks
• After playing through tracks, history filters them out on next session
• Rapid tab switches → no stale results applied
• Double-click another station quickly → no duplicate playlist clears
• Playback Options has a single Radio History submenu with source-specific entries
• History menu visible after disconnecting server (not only while connected)
• History page sorts Played column correctly (newest last when ↑)
• Starred radio respects current music folder selection

Implementation Gotchas

App Transport Security — cleartext HTTP streams need NSAllowsArbitraryLoads alone

Internet radio plays through the AudioStreaming library, which fetches the stream over URLSession (not AVFoundation). ATS therefore applies to it. The ATS exception key NSAllowsArbitraryLoadsForMedia only covers AVFoundation media loads — it does not cover URLSession. With only that key set, every cleartext http:// station was silently blocked: the stream stayed in bufferring at progress 0.0 and never reached playing, while https:// stations worked.

Sources/NullPlayer/Resources/Info.plist sets NSAllowsArbitraryLoads so http-only Icecast/SHOUTcast stations connect (issue #255). Radio stations are arbitrary user-supplied hosts, so NSExceptionDomains can't be enumerated — arbitrary loads is the correct key.

NSAllowsArbitraryLoads MUST be the ONLY key in the NSAppTransportSecurity dict (issue #310). On macOS 10.12+, if you pair it with any granular key — NSAllowsLocalNetworking, NSAllowsArbitraryLoadsForMedia, or NSAllowsArbitraryLoadsInWebContent — the system ignores NSAllowsArbitraryLoads and honors only the granular keys. In #310, a co-present NSAllowsLocalNetworking (it had been added for casting) silently re-enabled ATS for public hosts: cleartext radio failed with CFNetwork -1022 ("requires a secure connection") even though the global key was true, while local-network casting kept working (so it looked fine). The library fires didStartPlaying optimistically before the data task dies, so the UI shows "connected" but the clock never advances past 0:00. Fix was to delete NSAllowsLocalNetworking — NSAllowsArbitraryLoads alone is a superset that already permits local-network casting (Sonos/Chromecast/DLNA), so nothing regressed. Do not re-add any granular ATS key.