code-saksham-hash/resona

Purpose and Entry Points

Resona is an anonymous Android music-streaming client for YouTube Music’s private InnerTube APIs. It searches, browses, resolves protected audio streams, plays via a foreground media service, and persists local likes, history, and downloads.

Android startup and app-level dependency wiring are in app/src/main/java/com/resona/music/ResonaApplication.kt, app/src/main/java/com/resona/music/MainActivity.kt, and app/src/main/java/com/resona/music/di/AppModule.kt.

Module Boundary and Dependency Direction

The architecture is intentionally layered:

• core/domain is pure Kotlin: shared models plus the MusicRepository contract at core/domain/src/main/kotlin/com/resona/music/domain/repository/MusicRepository.kt.

• core/data implements remote access, extraction, and local persistence, centered on core/data/src/main/java/com/resona/music/data/repository/MusicRepositoryImpl.kt.

• Feature UI modules consume domain interfaces, while app provides concrete bindings through app/src/main/java/com/resona/music/di/RepositoryModule.kt.

• Playback is isolated from feature UI in core/player.

This prevents feature modules from directly accessing network clients or data implementations.

Navigation and Compose Feature Surface

The app shell owns destination definitions and navigation composition in app/src/main/java/com/resona/music/ui/navigation/Destinations.kt and app/src/main/java/com/resona/music/ui/navigation/NavGraph.kt.

Feature modules supply screens and view models for independently scoped flows: home (feature/home/src/main/java/com/resona/music/ui/home/HomeScreen.kt), search (feature/search/src/main/java/com/resona/music/ui/search/SearchViewModel.kt), library (feature/library/src/main/java/com/resona/music/ui/library/LibraryScreen.kt), and now-playing UI (feature/player/src/main/java/com/resona/music/ui/nowplaying/NowPlayingScreen.kt). Shared visual tokens/components reside in core/ui/src/main/java/com/resona/music/ui/theme/Theme.kt.

Repository and InnerTube Data Flow

UI view models invoke MusicRepository; its implementation converts InnerTube responses into domain models. Network construction is app-provided in app/src/main/java/com/resona/music/di/NetworkModule.kt, while API calls and transport models live in core/data/src/main/java/com/resona/music/data/remote/innertube/InnerTubeApi.kt and core/data/src/main/java/com/resona/music/data/remote/innertube/models/.

The remote boundary is YouTube Music InnerTube endpoints for search, player, browse, and radio/next operations. The client uses anonymous visitor-token-based access and retries across client identities through core/data/src/main/java/com/resona/music/data/extractor/InnerTubeExtractionClient.kt.

Stream Extraction and Deciphering

Playback cannot consume a song until the extractor obtains a usable media URL. core/data/src/main/java/com/resona/music/data/extractor/YouTubeStreamExtractor.kt coordinates player-response retrieval and protected URL resolution.

Signature and CDN-throttling transforms are derived from YouTube player JavaScript via core/data/src/main/java/com/resona/music/data/extractor/decipher/DecipherService.kt and core/data/src/main/java/com/resona/music/data/extractor/decipher/PlayerJsRepository.kt. JavaScript executes in Android WebView rather than a bundled JS runtime, behind core/data/src/main/java/com/resona/music/data/extractor/WebViewJsEngine.kt.

Playback Control Plane

core/player/src/main/java/com/resona/music/playback/PlayerService.kt is the Media3/ExoPlayer foreground-service and MediaSession boundary. It receives resolved stream data through the playback data-source wiring in core/player/src/main/java/com/resona/music/playback/PlaybackDataSourceModule.kt.

core/player/src/main/java/com/resona/music/playback/PlayerViewModel.kt exposes shared player state and transport actions to mini-player and now-playing surfaces, including queue-aware navigation.

On-Device State and Offline Content

Local user state remains device-local, using dedicated stores: likes at core/data/src/main/java/com/resona/music/data/likes/LikedSongsStore.kt, bounded play history at core/data/src/main/java/com/resona/music/data/history/PlayHistoryStore.kt, and downloaded-song metadata at core/data/src/main/java/com/resona/music/data/download/DownloadedSongsStore.kt.

core/data/src/main/java/com/resona/music/data/download/SongDownloader.kt materializes resolved streams into app storage using download-specific orchestration, separating offline persistence from streaming playback.