fix: connection issues

docs/TODO.md

@@ -68,14 +68,19 @@ Notes: verified on the FiiO via injected key events (a rotary volume knob may no
 emit `VOLUME_UP/DOWN` — hardware-dependent). Album art in the notification/session
 is pending item #5.
 
-## [ ] 4. Library browse — albums
+## [x] 4. Library browse — albums
 
-A screen to browse all albums on the server (artists can come later).
+Done. `AlbumsScreen` (library icon on the player) lists every album via
+`list album group albumartist` (`MpdCommands.listAlbums` → `MpdAlbum.listFrom`),
+sorted by artist then title. Tapping an album replaces the queue and plays it
+(`MpdClient.playAlbum` = `clear` + `findadd album … albumartist …` + `play`),
+then returns to the now-playing screen.
 
-- MPD commands: `list album group albumartist` (or `list album`), and
-  `find album "<name>"` to fetch an album's tracks; add to the queue with
-  `add`/`findadd`. Extend `MpdCommands` + `MpdClient`.
-- Grid or list of albums → tap to view/queue tracks.
+- Verified live: 149 albums listed and played correctly on the FiiO.
+- Placeholder disc icon per row (real art is item #5).
+- Interaction choice: tap = **replace queue + play** (the direct "play this
+  album" gesture). Could later add a long-press / menu for "add to queue" and an
+  album-detail/track view. Artist browse is a future extension.
 
 ## [ ] 5. Album / artist images
 
@@ -88,7 +93,7 @@ Pull artwork for the now-playing track and for the album browse grid.
 - Needs an image loader + caching. Coil (`io.coil-kt`) is the standard Compose
   choice; a custom `MpdArtFetcher` could feed it. Dependency → `deps.json` regen.
 
-## [ ] 6. BUG: idle connection drops after a few minutes → kicked to connect page
+## [x] 6. BUG: idle connection drops after a few minutes → kicked to connect page
 
 After a few minutes idling, the app surfaces **"connection closed mid-response"**
 and falls back to the connect screen. MALP does not do this.
@@ -108,8 +113,27 @@ and falls back to the connect screen. MALP does not do this.
   **auto-reconnect transparently** (re-open connections, re-issue `idle`, resync
   state) and keep showing the player. Consider a keepalive ping and, for
   backgrounded playback control, a foreground service / partial wakelock.
-- PARTIALLY ADDRESSED by item #3: the `mediaPlayback` foreground service now
-  keeps the process/connection alive in the background, which should stop Doze /
-  wifi power-save from tearing the sockets down (the most likely cause). Still
-  worth verifying over a long idle, and adding transparent auto-reconnect +
-  keepalive ping as defense-in-depth (e.g. against MPD `connection_timeout`).
+- PARTIALLY ADDRESSED by item #3: the `mediaPlayback` foreground service keeps
+  the process/connection alive in the background.
+
+**FIXED.** Root cause was two-fold: (a) the quiet command connection was reaped
+by MPD's `connection_timeout`, and (b) the idle loop treated *any* `IOException`
+(including that reap) as fatal → `Error` → connect page. Plus a Pi-Zero overload
+angle: volume-key floods + 2-round-trip refreshes. Fixes, all in `MpdClient`
+/`MpdConnectionManager`/`MpdConnection`:
+
+- **Keepalive `ping`** every 25s on the command connection — prevents the
+  `connection_timeout` reap and detects a dead socket early.
+- **Transparent auto-reconnect** (`triggerReconnect`/`reconnectLoop`): a transport
+  drop reopens both sockets in the background (state → `Connecting`, "Connecting…"
+  splash, player stays), retrying with backoff; only after
+  `MAX_RECONNECT_ATTEMPTS` does it surface `Error`. `MpdAckException` is
+  explicitly *not* treated as a connection failure.
+- **Volume throttle**: `setvol` writes are coalesced through a conflated channel
+  (~1 per 120 ms, latest value) — kills the flood from holding volume keys while
+  keeping accurate accumulation via `pendingVolume`.
+- **Command-list refresh**: `status`+`currentsong` fetched in one round-trip
+  (`MpdConnection.executeList`, `command_list_ok_begin`).
+
+Verified on the FiiO: Wi-Fi drop → "Connecting…" → auto-recovers to the player
+(no connect-page bounce); 6 rapid volume presses = exactly −30, throttled.