Files
subtracks/docs/implementation-plan.md
T

3.8 KiB

Implementation plan

The rewrite is delivered in vertical slices. Each phase leaves the app in a working, testable state.

Phase 0 - Foundation (done)

Nix devshell (JDK, Gradle, Android SDK, nushell, navidrome, gonic), Gradle Kotlin DSL at the repo root, a Compose skeleton, Roborazzi/Robolectric screenshot testing, and the carried-over launcher and notification assets. The app ships as com.subtracks.next.

Phase 1 - Data foundation (done)

Everything needed to mirror a server library locally:

  • MusicSource abstraction with SubsonicClient, SubsonicXml and SubsonicSource.
  • Room 3 schema on bundled SQLite, so the SQLite version and FTS5 are identical on every device.
  • SyncService: fetch first, then a single transaction of upserts with diff-based pruning.
  • FTS5 trigram search index over titles.
  • Unit tests (client, XML, sync, search), native integration tests against navidrome and gonic, and CI (unit, lint, integration) with warm caches.

Phase 2 - UI vertical slice (done)

Goal: a usable app for browsing a server, end to end.

  • Koin DI and DataStore-backed preferences (album sort); the unused app_settings Room table was removed in favour of DataStore.
  • App shell: a root gate that shows the add-server flow until a server exists, then the tabbed library screen matching the Flutter app (icon-only tabs for albums, artists, songs and playlists, with sync and settings actions), plus album and playlist detail screens and a monochrome theme.
  • Source setup: name/address/username/password with token-auth toggle, a connection test, save-and-sync, plus server switching and removal in settings.
  • Library browsing: albums (covers-only grid), artists, songs and playlists paged from Room (PagingSource) and rendered with LazyPagingItems, with Coil cover art served from stable media URLs.
  • Roborazzi screenshots for the eight new screens, rendered on demand for review (not committed).

Not done yet in this slice (deliberately): artist detail, cover-art tonal colour extraction, long-press menus, editing an existing server, and per-section sort/filter controls (only album sort is wired).

Phase 3 - Playback (in progress)

  • (done) Media3/ExoPlayer playback service, queue and now-playing UI: a MediaSessionService plus a mini player and a Now Playing screen.
  • (done) Media notifications and headset/Bluetooth controls, from the media session.
  • (done) A SQL-backed queue of references (whole playlist / album / song, each with an optional ordinal range) resolved lazily, with only a bounded window in memory and in the player.
  • (done) Streaming bitrate and preferred format from settings (maxBitRate/format, so the server transcodes as configured).
  • (done) Playing from the Songs tab: the tapped song queues the whole songs list at that position.
  • The queue view (add to queue / play next / reorder), and gapless format preferences.
  • Scrobbling and "now playing" back to the server.
  • Optional download/caching.

Phase 4 - Search, playlists, offline

  • Search UI over the FTS5 index (substring, ranked).
  • Playlist browsing and editing (create/add/remove), syncing changes back to the server.
  • Offline mode and downloads.

Phase 5 - Release

  • Change applicationId from com.subtracks.next to com.subtracks.
  • Signing, versioning and Fastlane metadata.
  • F-Droid submission. Their buildserver must have Gradle >= 9.6 and SDK 37, which this project targets; do not rely on the Gradle wrapper there (fdroidserver deletes gradlew and uses its own Gradle).

Deferred decisions

  • Whether to drop the plaintext-auth fallback or keep it behind an "insecure server" toggle.
  • Robolectric runs at SDK 35 while targetSdk is 37; aligning them changes the on-demand Roborazzi renders (nothing committed to re-record).
  • Whether to extract :core:data and friends once the UI has grown.