CRDT-based multi-device sync

androidApp/src/main/java/org/nsh07/pomodoro/service/TimerService.kt

@@ -91,7 +91,7 @@ class TimerService : Service(), KoinComponent {
 
     private val cs by lazy { stateRepository.colorScheme }
 
-    private lateinit var notificationStyle: NotificationCompat.ProgressStyle
+    private var notificationStyle = NotificationCompat.ProgressStyle()
 
     override fun onBind(intent: Intent?): IBinder? {
         return null

androidApp/src/main/java/org/nsh07/pomodoro/widget/HistoryAppWidget.kt

@@ -206,6 +206,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
         val history = listOf(
             Stat(
                 date = LocalDate.of(2026, 3, 12),
+                deviceId = "0",
                 focusTimeQ1 = 1617943 + 7200000,
                 focusTimeQ2 = 5704591,
                 focusTimeQ3 = 556490,
@@ -214,6 +215,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 13),
+                deviceId = "0",
                 focusTimeQ1 = 1128282 + 7200000,
                 focusTimeQ2 = 4590524,
                 focusTimeQ3 = 7747202,
@@ -222,6 +224,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 14),
+                deviceId = "0",
                 focusTimeQ1 = 1418079 + 7200000,
                 focusTimeQ2 = 8141785,
                 focusTimeQ3 = 5208864,
@@ -230,6 +233,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 15),
+                deviceId = "0",
                 focusTimeQ1 = 38960 + 7200000,
                 focusTimeQ2 = 9544172,
                 focusTimeQ3 = 2216626,
@@ -238,6 +242,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 16),
+                deviceId = "0",
                 focusTimeQ1 = 948108 + 7200000,
                 focusTimeQ2 = 7715257,
                 focusTimeQ3 = 648629,
@@ -246,6 +251,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 17),
+                deviceId = "0",
                 focusTimeQ1 = 1673932 + 7200000,
                 focusTimeQ2 = 7368028,
                 focusTimeQ3 = 6028910,
@@ -254,6 +260,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 18),
+                deviceId = "0",
                 focusTimeQ1 = 435688 + 7200000,
                 focusTimeQ2 = 9487983,
                 focusTimeQ3 = 248276,
@@ -262,6 +269,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 19),
+                deviceId = "0",
                 focusTimeQ1 = 1579291 + 7200000,
                 focusTimeQ2 = 3743344,
                 focusTimeQ3 = 3383617,
@@ -270,6 +278,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 20),
+                deviceId = "0",
                 focusTimeQ1 = 522247 + 7200000,
                 focusTimeQ2 = 7156785,
                 focusTimeQ3 = 5190730,
@@ -278,6 +287,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 21),
+                deviceId = "0",
                 focusTimeQ1 = 310048 + 7200000,
                 focusTimeQ2 = 5901959,
                 focusTimeQ3 = 441673,
@@ -286,6 +296,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 22),
+                deviceId = "0",
                 focusTimeQ1 = 1200000 + 7200000,
                 focusTimeQ2 = 4000000,
                 focusTimeQ3 = 3000000,
@@ -294,6 +305,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 23),
+                deviceId = "0",
                 focusTimeQ1 = 500000 + 7200000,
                 focusTimeQ2 = 8000000,
                 focusTimeQ3 = 1000000,
@@ -302,6 +314,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 24),
+                deviceId = "0",
                 focusTimeQ1 = 2000000 + 7200000,
                 focusTimeQ2 = 2000000,
                 focusTimeQ3 = 2000000,
@@ -310,6 +323,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 25),
+                deviceId = "0",
                 focusTimeQ1 = 0 + 7200000,
                 focusTimeQ2 = 10000000,
                 focusTimeQ3 = 0,
@@ -318,6 +332,7 @@ class HistoryAppWidget : GlanceAppWidget(), KoinComponent {
             ),
             Stat(
                 date = LocalDate.of(2026, 3, 26),
+                deviceId = "0",
                 focusTimeQ1 = 3000000 + 7200000,
                 focusTimeQ2 = 3000000,
                 focusTimeQ3 = 3000000,

androidApp/src/main/java/org/nsh07/pomodoro/widget/TodayAppWidget.kt

@@ -84,7 +84,7 @@ class TodayAppWidget : GlanceAppWidget(), KoinComponent {
     ) {
         val statRepository: StatRepository = get()
         val stat = statRepository.getTodayStat().first()
-            ?: Stat(LocalDate.now(), 0, 0, 0, 0, 0)
+            ?: Stat(LocalDate.now(), "0", 0, 0, 0, 0, 0)
 
         provideContent {
             key(LocalSize.current) {
@@ -205,6 +205,7 @@ class TodayAppWidget : GlanceAppWidget(), KoinComponent {
                     Content(
                         Stat(
                             date = LocalDate.of(2026, 3, 12),
+                            deviceId = "0",
                             focusTimeQ1 = 1617943,
                             focusTimeQ2 = 5704591,
                             focusTimeQ3 = 556490,

gradle/libs.versions.toml

@@ -20,6 +20,7 @@ junit = "4.13.2"
 junitVersion = "1.3.0"
 kotlin = "2.3.20"
 kotlinxCoroutines = "1.10.2"
+kotlinxSerializationJson = "1.11.0"
 ksp = "2.3.6"
 lifecycleRuntime = "2.10.0"
 materialKolor = "4.1.1"
@@ -64,6 +65,7 @@ filekit-core = { module = "io.github.vinceglb:filekit-core", version.ref = "file
 filekit-dialogs-compose = { module = "io.github.vinceglb:filekit-dialogs-compose", version.ref = "filekitDialogsCompose" }
 jlayer-player = { module = "dev.mccue:jlayer-player", version.ref = "jlayerPlayer" }
 junit = { group = "junit", name = "junit", version.ref = "junit" }
+kotlinx-serialization-json = { module = "org.jetbrains.kotlinx:kotlinx-serialization-json", version.ref = "kotlinxSerializationJson" }
 material-kolor = { module = "com.materialkolor:material-kolor", version.ref = "materialKolor" }
 revenuecat-purchases = { module = "com.revenuecat.purchases:purchases", version.ref = "revenuecat" }
 revenuecat-purchases-ui = { module = "com.revenuecat.purchases:purchases-ui", version.ref = "revenuecat" }

shared/build.gradle.kts

@@ -79,6 +79,7 @@ kotlin {
             implementation(libs.koin.compose.viewmodel)
 
             implementation(libs.androidx.room.runtime)
+            implementation(libs.kotlinx.serialization.json)
 
             implementation(libs.vico.compose.m3)
             implementation(libs.material.kolor)

shared/schemas/org.nsh07.pomodoro.data.AppDatabase/3.json

@@ -0,0 +1,146 @@
+{
+  "formatVersion": 1,
+  "database": {
+    "version": 3,
+    "identityHash": "710379259efe0b7d0cd521b4698fc0c5",
+    "entities": [
+      {
+        "tableName": "int_preference",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`key` TEXT NOT NULL, `value` INTEGER NOT NULL, PRIMARY KEY(`key`))",
+        "fields": [
+          {
+            "fieldPath": "key",
+            "columnName": "key",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "value",
+            "columnName": "value",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "key"
+          ]
+        }
+      },
+      {
+        "tableName": "boolean_preference",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`key` TEXT NOT NULL, `value` INTEGER NOT NULL, PRIMARY KEY(`key`))",
+        "fields": [
+          {
+            "fieldPath": "key",
+            "columnName": "key",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "value",
+            "columnName": "value",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "key"
+          ]
+        }
+      },
+      {
+        "tableName": "string_preference",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`key` TEXT NOT NULL, `value` TEXT NOT NULL, PRIMARY KEY(`key`))",
+        "fields": [
+          {
+            "fieldPath": "key",
+            "columnName": "key",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "value",
+            "columnName": "value",
+            "affinity": "TEXT",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "key"
+          ]
+        }
+      },
+      {
+        "tableName": "stat",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`date` TEXT NOT NULL, `deviceId` TEXT NOT NULL, `updatedAt` INTEGER NOT NULL, `focusTimeQ1` INTEGER NOT NULL, `focusTimeQ2` INTEGER NOT NULL, `focusTimeQ3` INTEGER NOT NULL, `focusTimeQ4` INTEGER NOT NULL, `breakTime` INTEGER NOT NULL, PRIMARY KEY(`date`, `deviceId`))",
+        "fields": [
+          {
+            "fieldPath": "date",
+            "columnName": "date",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "deviceId",
+            "columnName": "deviceId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "updatedAt",
+            "columnName": "updatedAt",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "focusTimeQ1",
+            "columnName": "focusTimeQ1",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "focusTimeQ2",
+            "columnName": "focusTimeQ2",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "focusTimeQ3",
+            "columnName": "focusTimeQ3",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "focusTimeQ4",
+            "columnName": "focusTimeQ4",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "breakTime",
+            "columnName": "breakTime",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "date",
+            "deviceId"
+          ]
+        }
+      }
+    ],
+    "setupQueries": [
+      "CREATE TABLE IF NOT EXISTS room_master_table (id INTEGER PRIMARY KEY,identity_hash TEXT)",
+      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, '710379259efe0b7d0cd521b4698fc0c5')"
+    ]
+  }
+}

shared/src/androidMain/kotlin/org/nsh07/pomodoro/data/AndroidBackupRestoreManager.kt

@@ -22,10 +22,14 @@ import android.content.Intent
 import android.provider.DocumentsContract
 import androidx.core.net.toUri
 import androidx.room.RoomRawQuery
+import io.github.vinceglb.filekit.FileKit
 import io.github.vinceglb.filekit.PlatformFile
+import io.github.vinceglb.filekit.cacheDir
 import io.github.vinceglb.filekit.path
+import io.github.vinceglb.filekit.writeString
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
+import kotlinx.serialization.json.Json
 import org.nsh07.pomodoro.BuildKonfig
 import java.io.File
 import java.io.FileInputStream
@@ -34,9 +38,13 @@ import kotlin.time.Clock
 
 class AndroidBackupRestoreManager(
     private val database: AppDatabase,
+    private val statDao: StatDao,
     private val systemDao: SystemDao,
-    private val context: Context
+    private val context: Context,
+    deviceIdStore: DeviceIdStore
 ) : BackupRestoreManager {
+    val deviceId = deviceIdStore.deviceId
+
     override suspend fun performBackup(directory: PlatformFile) {
         withContext(Dispatchers.IO) {
             systemDao.checkpoint(RoomRawQuery("PRAGMA wal_checkpoint(full)"))
@@ -86,6 +94,37 @@ class AndroidBackupRestoreManager(
         }
     }
 
+    override suspend fun exportSyncFile(): PlatformFile {
+        val stats = statDao.getAllRows()
+
+        val payload = SyncPayload(
+            schemaVersion = DB_SCHEMA_VERSION,
+            exportedAt = System.currentTimeMillis(),
+            deviceId = deviceId.value,
+            stats = stats
+        )
+
+        val outputFile =
+            PlatformFile(FileKit.cacheDir, "tomato-backup-${Clock.System.now()}.tomatoSync")
+
+        withContext(Dispatchers.IO) {
+            val content = Json.encodeToString(payload)
+            outputFile.writeString(content)
+        }
+
+        return outputFile
+    }
+
+    override suspend fun importSyncFile(file: PlatformFile?) {
+        if (file == null) return
+        withContext(Dispatchers.IO) {
+            val bytes = File(file.path).readBytes()
+            val content = bytes.decodeToString()
+            val payload = Json.decodeFromString<SyncPayload>(content)
+            statDao.insertStatsIfNewer(payload.stats)
+        }
+    }
+
     override fun restartApp() {
         val packageManager = context.packageManager
         val intent = packageManager.getLaunchIntentForPackage(context.packageName)