Add Room database as track summary cache

Adds TrackEntity/TrackDao/NavDatabase (Room v2.6.1). TrackRepository
writes to Room on stopTrack() and importTrack(), and backfills existing
tracks on first cold-start when the Room cache is empty. GPX/SAF remains
source-of-truth for reinstall; Room is a fast metadata cache for future
list-view optimisation.

https://claude.ai/code/session_01KXYBuAHZkvv63DeUG6XaZD

5 files changed, 104 insertions, 2 deletions

diff --git a/android-app/app/src/main/kotlin/org/terst/nav/NavApplication.kt b/android-app/app/src/main/kotlin/org/terst/nav/NavApplication.kt
index 0fe5708..3873002 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/NavApplication.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/NavApplication.kt
@@ -2,6 +2,7 @@ package org.terst.nav
 
 import android.app.Application
 import com.google.firebase.crashlytics.FirebaseCrashlytics
+import org.terst.nav.db.NavDatabase
 import org.terst.nav.settings.FeatureFlags
 import java.io.File
 import java.io.PrintWriter
@@ -21,6 +22,8 @@ class NavApplication : Application() {
         lateinit var trackRepository: org.terst.nav.track.TrackRepository
         lateinit var boatProfileRepository: org.terst.nav.tripreport.BoatProfileRepository
         lateinit var vesselRepository: org.terst.nav.vessel.VesselRepository
+        lateinit var database: NavDatabase
+            private set
         var isTesting: Boolean = false
             get() {
                 if (field) return true
@@ -36,8 +39,9 @@ class NavApplication : Application() {
     override fun onCreate() {
         super.onCreate()
         featureFlags = FeatureFlags(this)
+        database = NavDatabase.get(this)
         logbookRepository = org.terst.nav.logbook.LogbookRepository(org.terst.nav.logbook.LogbookStorage(this))
-        trackRepository = org.terst.nav.track.TrackRepository(this)
+        trackRepository = org.terst.nav.track.TrackRepository(this, database.trackDao())
         boatProfileRepository = org.terst.nav.tripreport.BoatProfileRepository(this)
         vesselRepository = org.terst.nav.vessel.VesselRepository(this)
         FirebaseCrashlytics.getInstance().sendUnsentReports()
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/db/NavDatabase.kt b/android-app/app/src/main/kotlin/org/terst/nav/db/NavDatabase.kt
new file mode 100644
index 0000000..ccef58b
--- /dev/null
+++ b/android-app/app/src/main/kotlin/org/terst/nav/db/NavDatabase.kt
@@ -0,0 +1,26 @@
+package org.terst.nav.db
+
+import android.content.Context
+import androidx.room.Database
+import androidx.room.Room
+import androidx.room.RoomDatabase
+import org.terst.nav.track.TrackDao
+import org.terst.nav.track.TrackEntity
+
+@Database(entities = [TrackEntity::class], version = 1, exportSchema = false)
+abstract class NavDatabase : RoomDatabase() {
+
+    abstract fun trackDao(): TrackDao
+
+    companion object {
+        @Volatile private var INSTANCE: NavDatabase? = null
+
+        fun get(context: Context): NavDatabase = INSTANCE ?: synchronized(this) {
+            INSTANCE ?: Room.databaseBuilder(
+                context.applicationContext,
+                NavDatabase::class.java,
+                "nav.db"
+            ).build().also { INSTANCE = it }
+        }
+    }
+}
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackDao.kt b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackDao.kt
new file mode 100644
index 0000000..9c628df
--- /dev/null
+++ b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackDao.kt
@@ -0,0 +1,25 @@
+package org.terst.nav.track
+
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.OnConflictStrategy
+import androidx.room.Query
+
+@Dao
+interface TrackDao {
+
+    @Query("SELECT * FROM tracks ORDER BY startMs DESC")
+    suspend fun getAll(): List<TrackEntity>
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    suspend fun insert(entity: TrackEntity)
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    suspend fun insertAll(entities: List<TrackEntity>)
+
+    @Query("DELETE FROM tracks")
+    suspend fun clear()
+
+    @Query("SELECT COUNT(*) FROM tracks")
+    suspend fun count(): Int
+}
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackEntity.kt b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackEntity.kt
new file mode 100644
index 0000000..502bfba
--- /dev/null
+++ b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackEntity.kt
@@ -0,0 +1,35 @@
+package org.terst.nav.track
+
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+
+@Entity(tableName = "tracks")
+data class TrackEntity(
+    @PrimaryKey val startMs: Long,
+    val distanceNm: Double,
+    val durationMs: Long,
+    val maxSogKt: Double,
+    val avgSogKt: Double,
+    val avgWindKt: Double?,
+    val avgWaveHeightM: Double?,
+    val tackCount: Int,
+    val startLat: Double,
+    val startLon: Double,
+    val endLat: Double,
+    val endLon: Double
+)
+
+fun SavedTrack.toEntity(): TrackEntity = TrackEntity(
+    startMs       = startMs,
+    distanceNm    = summary.distanceNm,
+    durationMs    = summary.durationMs,
+    maxSogKt      = summary.maxSogKt,
+    avgSogKt      = summary.avgSogKt,
+    avgWindKt     = summary.avgWindKt,
+    avgWaveHeightM = summary.avgWaveHeightM,
+    tackCount     = tacks.size,
+    startLat      = points.first().lat,
+    startLon      = points.first().lon,
+    endLat        = points.last().lat,
+    endLon        = points.last().lon
+)
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackRepository.kt b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackRepository.kt
index c40c9c2..019f169 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackRepository.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackRepository.kt
@@ -11,7 +11,7 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 import org.terst.nav.ui.NavLogger
 
-class TrackRepository(context: Context) {
+class TrackRepository(context: Context, private val trackDao: TrackDao) {
 
     private val storage = TrackStorage(context)
 
@@ -58,6 +58,8 @@ class TrackRepository(context: Context) {
             Log.e("TrackRepository", "GPX save failed — ${points.size} points will be lost on restart")
             NavLogger.e("track", "saveTrack returned false — ${points.size} pts lost on restart")
         }
+        val savedTrack = SavedTrack(points, trackStartMs, summary, TackDetector.detectTacks(points))
+        runCatching { trackDao.insert(savedTrack.toEntity()) }
         summary
     }
 
@@ -72,6 +74,8 @@ class TrackRepository(context: Context) {
         if (saved) {
             _pastTracks.add(0, points)
             NavLogger.i("track", "importTrack: saved ${points.size} pts startMs=$startMs")
+            val savedTrack = points.toSavedTrack()
+            runCatching { trackDao.insert(savedTrack.toEntity()) }
         } else {
             NavLogger.e("track", "importTrack: save failed for ${points.size} pts")
         }
@@ -125,6 +129,14 @@ class TrackRepository(context: Context) {
 
             _pastTracks.addAll(stored)
             NavLogger.i("track", "getPastTracks: total in memory=${_pastTracks.size}")
+            if (stored.isNotEmpty() && trackDao.count() == 0) {
+                // One-time backfill of Room cache from existing GPX files
+                val entities = stored.mapNotNull { pts ->
+                    runCatching { pts.toSavedTrack().toEntity() }.getOrNull()
+                }
+                if (entities.isNotEmpty()) trackDao.insertAll(entities)
+                NavLogger.i("track", "getPastTracks: backfilled ${entities.size} tracks into Room")
+            }
         }
         _pastTracks.toList()
     }