feat: add canonical beat pattern TYPE_BEATS, not synced to server

app/src/main/java/at/lockstep/player/LockstepViewModel.kt

@@ -167,8 +167,9 @@ class LockstepViewModel(
         }
 
     /**
-     * Writes one JSON file under public Documents/Lockstep/{sessionFolder}/ for the track described
-     * by [event], records file metadata, and uploads when signed in. Skips when [beatTimesMs] is empty.
+     * Writes session annotation JSON under Documents/Lockstep/{sessionFolder}/ (synced when signed in)
+     * and canonical beat JSON under Documents/Lockstep/Beats/{playlist_name}/ (local file_metadata only).
+     * Skips when [beatTimesMs] is empty.
      */
     fun persistBeatAnnotation(
         playlistId: String,
@@ -184,9 +185,10 @@ class LockstepViewModel(
             val pairing = pairingDao.findForTrack(playlistId, event.trackId)
             val docId = BeatAnnotationStorage.mp3DocumentContentId(pairing?.localUri)
             val contentId = docId.ifBlank { event.trackId }
-            val uri =
+            val appContext = getApplication<Application>()
+            val annotationUri =
                 BeatAnnotationStorage.writeAnnotationsFile(
-                    context = getApplication(),
+                    context = appContext,
                     sessionFolder = sessionFolder,
                     playlistDisplayName = playlistDisplayName,
                     trackQueueIndex0Based = event.queueIndex,
@@ -195,18 +197,66 @@ class LockstepViewModel(
                     artist = event.artist,
                     beatTimesMs = beatTimesMs,
                 ) ?: return@launch
-            val entry =
-                FileMetadataEntity(
-                    fileUri = uri.toString(),
-                    trackId = event.trackId,
-                    type = FileMetadataEntity.TYPE_ANNOTATION,
-                    version = BuildConfig.VERSION_CODE,
-                )
-            val id = fileMetadataDao.insert(entry)
+            recordMetadataEntry(
+                fileUri = annotationUri.toString(),
+                trackId = event.trackId,
+                type = FileMetadataEntity.TYPE_ANNOTATION,
+            )
+            val beatsUri =
+                BeatAnnotationStorage.writeBeatsFile(
+                    context = appContext,
+                    playlistDisplayName = playlistDisplayName,
+                    trackQueueIndex0Based = event.queueIndex,
+                    contentId = contentId,
+                    title = event.title,
+                    artist = event.artist,
+                    beatTimesMs = beatTimesMs,
+                ) ?: return@launch
+            recordOrUpdateMetadataEntry(
+                fileUri = beatsUri.toString(),
+                trackId = event.trackId,
+                type = FileMetadataEntity.TYPE_BEATS,
+            )
+        }
+    }
+
+    private suspend fun recordMetadataEntry(
+        fileUri: String,
+        trackId: String,
+        type: String,
+    ) {
+        val now = System.currentTimeMillis()
+        val beats = type == FileMetadataEntity.TYPE_BEATS
+        val entry =
+            FileMetadataEntity(
+                fileUri = fileUri,
+                trackId = trackId,
+                type = type,
+                version = BuildConfig.VERSION_CODE,
+                synced = beats,
+                lastSyncedAt = if (beats) now else null,
+            )
+        val id = fileMetadataDao.insert(entry)
+        if (!beats) {
             syncMetadataEntry(entry.copy(id = id))
         }
     }
 
+    private suspend fun recordOrUpdateMetadataEntry(
+        fileUri: String,
+        trackId: String,
+        type: String,
+    ) {
+        val version = BuildConfig.VERSION_CODE
+        val now = System.currentTimeMillis()
+        val existing = fileMetadataDao.findByTrackIdAndType(trackId, type)
+        if (existing != null) {
+            fileMetadataDao.updateFile(existing.id, fileUri, version, now)
+        } else {
+            recordMetadataEntry(fileUri, trackId, type)
+        }
+    }
+
     /**
      * Writes one JSON file under public Documents/Lockstep/{runSessionFolder}/ when a track finishes or is skipped.
      * Skips when [samples] is empty or the track has no paired local URI.
@@ -333,7 +383,7 @@ class LockstepViewModel(
                     version = entry.version,
                     collection = collection,
                 )
-                fileMetadataDao.markSynced(entry.id)
+                fileMetadataDao.markSynced(entry.id, System.currentTimeMillis())
                 true
             } catch (e: IOException) {
                 Log.w(METADATA_TAG, "metadata sync failed id=${entry.id}", e)