Add DatabaseProvider for data sharing and add real-time sync triggers with openScale sync

android_app/app/src/main/AndroidManifest.xml

@@ -3,7 +3,20 @@
     xmlns:tools="http://schemas.android.com/tools">
 
     <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
-    <uses-permission android:name="android.permission.BLUETOOTH_SCAN" android:usesPermissionFlags="neverForLocation" tools:targetApi="s"/>
+    <uses-permission android:name="android.permission.BLUETOOTH_SCAN" android:usesPermissionFlags="neverForLocation" />
+
+    <permission
+        android:name="${applicationId}.READ_WRITE_DATA"
+        android:description="@string/permission_read_write_data_description"
+        android:label="@string/permission_read_write_data_label"
+        android:protectionLevel="dangerous" />
+
+    <uses-feature android:name="android.hardware.bluetooth_le" android:required="false"/>
+
+    <queries>
+        <package android:name="com.health.openscale.sync.oss" />
+        <package android:name="com.health.openscale.sync" />
+    </queries>
 
     <application
         android:allowBackup="true"
@@ -27,13 +40,20 @@
 
         <provider
             android:name="androidx.core.content.FileProvider"
-            android:authorities="${applicationId}.provider"
+            android:authorities="${applicationId}.file_provider"
             android:exported="false"
             android:grantUriPermissions="true">
         <meta-data
             android:name="android.support.FILE_PROVIDER_PATHS"
             android:resource="@xml/file_paths" />
-    </provider>
+        </provider>
+        <provider
+            android:name=".core.database.DatabaseProvider"
+            android:authorities="${applicationId}.provider"
+            android:enabled="true"
+            android:exported="true"
+            android:permission="${applicationId}.READ_WRITE_DATA">
+        </provider>
     </application>
 
 </manifest>

android_app/app/src/main/java/com/health/openscale/MainActivity.kt

@@ -17,6 +17,7 @@
  */
 package com.health.openscale
 
+import android.app.Application
 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
@@ -165,7 +166,7 @@ class MainActivity : ComponentActivity() {
         setContent {
             OpenScaleTheme {
                 val sharedViewModel: SharedViewModel = viewModel(
-                    factory = provideSharedViewModelFactory(databaseRepository, userSettingsRepository)
+                    factory = provideSharedViewModelFactory(application, databaseRepository, userSettingsRepository)
                 )
 
                 val view = LocalView.current
@@ -193,13 +194,14 @@ class MainActivity : ComponentActivity() {
  * @return A [ViewModelProvider.Factory] for [SharedViewModel].
  */
 private fun provideSharedViewModelFactory(
+    application : Application,
     databaseRepository: DatabaseRepository,
     userSettingsRepository: UserSettingsRepository
 ): ViewModelProvider.Factory = object : ViewModelProvider.Factory {
     override fun <T : ViewModel> create(modelClass: Class<T>): T {
         if (modelClass.isAssignableFrom(SharedViewModel::class.java)) {
             @Suppress("UNCHECKED_CAST")
-            return SharedViewModel(databaseRepository, userSettingsRepository) as T
+            return SharedViewModel(application, databaseRepository, userSettingsRepository) as T
         }
         throw IllegalArgumentException("Unknown ViewModel class: ${modelClass.name}")
     }

android_app/app/src/main/java/com/health/openscale/core/database/DatabaseProvider.kt

@@ -0,0 +1,536 @@
+/*
+ * openScale
+ * Copyright (C) 2025 olie.xdev <olie.xdeveloper@googlemail.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.health.openscale.core.database
+
+import android.content.ContentProvider
+import android.content.ContentUris
+import android.content.ContentValues
+import android.content.UriMatcher
+import android.database.Cursor
+import android.database.MatrixCursor
+import android.net.Uri
+import com.health.openscale.BuildConfig
+import com.health.openscale.core.data.Measurement
+import com.health.openscale.core.data.MeasurementTypeKey
+import com.health.openscale.core.data.MeasurementValue
+import com.health.openscale.core.utils.LogManager
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.runBlocking
+
+/**
+ * Exposes the user and measurement data from openScale via
+ * [Android Content Providers](https://developer.android.com/guide/topics/providers/content-providers).
+ * This version is adapted to use DatabaseRepository internally while maintaining the external interface.
+ */
+class DatabaseProvider : ContentProvider() {
+    private val TAG = "DatabaseProvider"
+
+    private lateinit var databaseRepository: DatabaseRepository
+
+    object UserColumns {
+        const val _ID = "_ID"
+        const val NAME = "username"
+    }
+
+    object MeasurementColumns {
+        const val _ID = "_ID"
+        const val DATETIME = "datetime"
+        const val WEIGHT = "weight"
+        const val BODY_FAT = "fat"
+        const val WATER = "water"
+        const val MUSCLE = "muscle"
+    }
+
+    override fun onCreate(): Boolean {
+        val appContext = context!!.applicationContext
+        return try {
+            LogManager.init(appContext, false)
+            val appDbInstance = AppDatabase.getInstance(appContext)
+            databaseRepository = DatabaseRepository(
+                database = appDbInstance,
+                userDao = appDbInstance.userDao(),
+                measurementDao = appDbInstance.measurementDao(),
+                measurementTypeDao = appDbInstance.measurementTypeDao(),
+                measurementValueDao = appDbInstance.measurementValueDao()
+            )
+            LogManager.i(TAG, "DatabaseProvider initialized successfully.")
+            true
+        } catch (e: Exception) {
+            LogManager.e(TAG, "Failed to initialize DatabaseProvider: ${e.message}", e)
+            false
+        }
+    }
+
+    override fun getType(uri: Uri): String? {
+        return when (uriMatcher.match(uri)) {
+            MATCH_TYPE_META -> "vnd.android.cursor.item/vnd.$AUTHORITY.meta"
+            MATCH_TYPE_USER_LIST -> "vnd.android.cursor.dir/vnd.$AUTHORITY.user"
+            MATCH_TYPE_MEASUREMENT_LIST_FOR_USER -> "vnd.android.cursor.dir/vnd.$AUTHORITY.measurement"
+            else -> null
+        }
+    }
+
+    override fun query(
+        uri: Uri,
+        projection: Array<String?>?,
+        selection: String?,
+        selectionArgs: Array<String?>?,
+        sortOrder: String?
+    ): Cursor? {
+        if (!::databaseRepository.isInitialized) {
+            LogManager.e(TAG, "DatabaseRepository not initialized in query.")
+            return null
+        }
+
+        val cursor: Cursor = when (uriMatcher.match(uri)) {
+            MATCH_TYPE_META -> {
+                MatrixCursor(arrayOf("apiVersion", "versionCode"), 1).apply {
+                    addRow(arrayOf<Any>(API_VERSION, BuildConfig.VERSION_CODE))
+                }
+            }
+            MATCH_TYPE_USER_LIST -> {
+                runBlocking {
+                    try {
+                        val users = databaseRepository.getAllUsers().first()
+                        val currentProjection = projection ?: arrayOf(UserColumns._ID, UserColumns.NAME)
+                        val matrixCursor = MatrixCursor(currentProjection)
+                        users.forEach { user ->
+                            val rowData = mutableListOf<Any?>()
+                            if (currentProjection.contains(UserColumns._ID)) rowData.add(user.id.toLong())
+                            if (currentProjection.contains(UserColumns.NAME)) rowData.add(user.name)
+                            matrixCursor.addRow(rowData.toTypedArray())
+                        }
+                        matrixCursor
+                    } catch (e: Exception) {
+                        LogManager.e(TAG, "Error querying users: ${e.message}", e)
+                        MatrixCursor(projection ?: arrayOf(UserColumns._ID), 0)
+                    }
+                }
+            }
+            MATCH_TYPE_MEASUREMENT_LIST_FOR_USER -> {
+                val userIdFromUri = try { ContentUris.parseId(uri).toInt() } catch (e: NumberFormatException) {
+                    LogManager.e(TAG, "Invalid User ID in URI for measurement query: $uri", e)
+                    return null
+                }
+                runBlocking {
+                    try {
+                        val measurementsWithValuesList =
+                            databaseRepository.getMeasurementsWithValuesForUser(userIdFromUri).first()
+
+                        val defaultMeasurementProjection = arrayOf(
+                            MeasurementColumns._ID,
+                            MeasurementColumns.DATETIME,
+                            MeasurementColumns.WEIGHT,
+                            MeasurementColumns.BODY_FAT,
+                            MeasurementColumns.WATER,
+                            MeasurementColumns.MUSCLE
+                        )
+                        val currentProjection = projection ?: defaultMeasurementProjection
+                        val matrixCursor = MatrixCursor(currentProjection)
+
+                        val allMeasurementTypes = databaseRepository.getAllMeasurementTypes().first()
+                        val typeIdMap = allMeasurementTypes.associate { it.key to it.id }
+
+                        measurementsWithValuesList.forEachIndexed { index, mcv -> // mcv is MeasurementWithValues
+                            val measurement = mcv.measurement
+                            val rowData = mutableListOf<Any?>()
+
+                            fun findValue(key: MeasurementTypeKey): Float? {
+                                val typeId = typeIdMap[key] ?: return null
+                                return mcv.values.find { it.type.id == typeId }?.value?.floatValue
+                            }
+
+                            if (currentProjection.contains(MeasurementColumns._ID)) rowData.add(measurement.id)
+                            if (currentProjection.contains(MeasurementColumns.DATETIME)) rowData.add(measurement.timestamp)
+                            if (currentProjection.contains(MeasurementColumns.WEIGHT)) rowData.add(findValue(MeasurementTypeKey.WEIGHT))
+                            if (currentProjection.contains(MeasurementColumns.BODY_FAT)) rowData.add(findValue(MeasurementTypeKey.BODY_FAT) ?: 0.0f)
+                            if (currentProjection.contains(MeasurementColumns.WATER)) rowData.add(findValue(MeasurementTypeKey.WATER) ?: 0.0f)
+                            if (currentProjection.contains(MeasurementColumns.MUSCLE)) rowData.add(findValue(MeasurementTypeKey.MUSCLE) ?: 0.0f)
+
+                            LogManager.d(TAG, "Query Row #${index + 1} for user $userIdFromUri (MeasID: ${measurement.id}): ${
+                                currentProjection.zip(rowData).joinToString { "${it.first}=${it.second}" }
+                            }")
+
+                            matrixCursor.addRow(rowData.toTypedArray())
+                        }
+                        matrixCursor
+                    } catch (e: Exception) {
+                        LogManager.e(TAG, "Error querying measurements for user $userIdFromUri: ${e.message}", e)
+                        MatrixCursor(projection ?: arrayOf(MeasurementColumns.DATETIME), 0)
+                    }
+                }
+            }
+            else -> throw IllegalArgumentException("Unknown URI for query: $uri")
+        }
+        cursor.setNotificationUri(context!!.contentResolver, uri)
+        return cursor
+    }
+
+    override fun insert(uri: Uri, values: ContentValues?): Uri? {
+        if (!::databaseRepository.isInitialized) {
+            LogManager.e(TAG, "DatabaseRepository not initialized in insert.")
+            return null
+        }
+        if (values == null) {
+            LogManager.w(TAG, "Attempted to insert null ContentValues.")
+            return null
+        }
+
+        when (uriMatcher.match(uri)) {
+            MATCH_TYPE_MEASUREMENT_LIST_FOR_USER -> {
+                val userIdFromUri = try { ContentUris.parseId(uri).toInt() } catch (e: NumberFormatException) {
+                    LogManager.e(TAG, "Invalid User ID in URI for measurement insert: $uri", e)
+                    return null
+                }
+
+                if (values.containsKey(MeasurementColumns._ID)) {
+                    val idFromValues = values.getAsInteger(MeasurementColumns._ID)
+                    if (idFromValues != null && idFromValues != userIdFromUri) {
+                        LogManager.w(TAG, "User ID in ContentValues ($idFromValues) mismatches User ID in URI ($userIdFromUri) for insert. Using User ID from URI.")
+                    }
+                }
+
+                val datetime = values.getAsLong(MeasurementColumns.DATETIME)
+                if (datetime == null) {
+                    LogManager.e(TAG, "Cannot insert measurement: '${MeasurementColumns.DATETIME}' is missing. userId=$userIdFromUri")
+                    return null
+                }
+                // Weight is considered mandatory for this provider's insert operation
+                val weight = values.getAsFloat(MeasurementColumns.WEIGHT)
+                if (weight == null) {
+                    LogManager.e(TAG, "Cannot insert measurement: '${MeasurementColumns.WEIGHT}' is missing. datetime=$datetime, userId=$userIdFromUri")
+                    return null
+                }
+
+
+                val measurement = Measurement(
+                    // id = 0, // Room will generate this if it's an AutoGenerate PrimaryKey
+                    userId = userIdFromUri,
+                    timestamp = datetime
+                )
+
+                val measurementValuesToInsert = mutableListOf<MeasurementValue>()
+                var weightTypeIdFound: Int? = null // To ensure weight type exists
+
+                runBlocking {
+                    val allMeasurementTypes = databaseRepository.getAllMeasurementTypes().first()
+                    val typeIdMap = allMeasurementTypes.associate { it.key to it.id }
+                    weightTypeIdFound = typeIdMap[MeasurementTypeKey.WEIGHT]
+
+                    fun addValueIfPresent(cvKey: String, typeKey: MeasurementTypeKey, isMandatory: Boolean = false) {
+                        if (values.containsKey(cvKey)) {
+                            val floatValue = values.getAsFloat(cvKey)
+                            if (floatValue != null) {
+                                typeIdMap[typeKey]?.let { typeId ->
+                                    measurementValuesToInsert.add(
+                                        MeasurementValue(
+                                            measurementId = 0,
+                                            typeId = typeId,
+                                            floatValue = floatValue
+                                        )
+                                    )
+                                } ?: LogManager.w(TAG, "$typeKey MeasurementTypeKey not found. Cannot insert $cvKey value for key $cvKey.")
+                            } else {
+                                if (isMandatory) {
+                                    LogManager.e(TAG, "Mandatory value for $cvKey ($typeKey) is missing and null in ContentValues.")
+                                }
+                            }
+                        } else {
+                            if (isMandatory) {
+                                LogManager.e(TAG, "Mandatory key $cvKey ($typeKey) is not present in ContentValues.")
+                            }
+                        }
+                    }
+
+
+                    // Add weight (already checked for nullability)
+                    if (weightTypeIdFound != null) {
+                        measurementValuesToInsert.add(
+                            MeasurementValue(
+                                measurementId = 0,
+                                typeId = weightTypeIdFound!!,
+                                floatValue = weight
+                            )
+                        )
+                    } else {
+                        // This case should be caught by the mandatory weight check, but as a safeguard:
+                        LogManager.e(TAG, "Weight MeasurementTypeKey not found internally, though weight value was provided.")
+                    }
+
+                    addValueIfPresent(MeasurementColumns.BODY_FAT, MeasurementTypeKey.BODY_FAT)
+                    addValueIfPresent(MeasurementColumns.WATER, MeasurementTypeKey.WATER)
+                    addValueIfPresent(MeasurementColumns.MUSCLE, MeasurementTypeKey.MUSCLE)
+                }
+
+                if (weightTypeIdFound == null) { // Double check if weight type ID was resolved
+                    LogManager.e(TAG, "Weight MeasurementTypeKey system configuration issue. Cannot insert essential weight value.")
+                    return null
+                }
+
+
+                if (measurementValuesToInsert.isEmpty()) {
+                    LogManager.w(TAG, "No valid measurement values to insert (after mandatory weight). userId=$userIdFromUri, datetime=$datetime")
+                    return null // Or decide to insert a measurement with no values if that's valid
+                }
+
+                try {
+                    val insertedMeasurementId: Long? = runBlocking {
+                        val pair = Pair(measurement, measurementValuesToInsert)
+                        val ids = databaseRepository.insertMeasurementsWithValues(listOf(pair)) // Expects List<Pair<Measurement, List<MeasurementValue>>>
+                        ids.firstOrNull() // Returns list of inserted measurement IDs
+                    }
+
+                    if (insertedMeasurementId != null && insertedMeasurementId > 0) {
+                        // Notify change on the general list URI for this user
+                        context!!.contentResolver.notifyChange(uri, null)
+                        LogManager.d(TAG, "Measurement inserted with ID: $insertedMeasurementId. Old API compatibility: returning null.")
+                        return null
+                    } else {
+                        LogManager.e(TAG, "Failed to insert measurement via Room or no ID returned.")
+                        return null
+                    }
+                } catch (e: Exception) {
+                    LogManager.e(TAG, "Error during Room insert operation: ${e.message}", e)
+                    return null
+                }
+            }
+            else -> throw IllegalArgumentException("Unknown URI for insert: $uri.")
+        }
+    }
+
+    override fun update(
+        uri: Uri,
+        values: ContentValues?,
+        selection: String?,
+        selectionArgs: Array<String?>?
+    ): Int {
+        if (!::databaseRepository.isInitialized) {
+            LogManager.e(TAG, "DatabaseRepository not initialized in update.")
+            return 0 // Return 0 rows affected
+        }
+        if (values == null || values.isEmpty) {
+            LogManager.w(TAG, "Attempted to update with null or empty ContentValues.")
+            return 0 // Return 0 rows affected
+        }
+
+        var rowsAffected = 0
+
+        when (uriMatcher.match(uri)) {
+            MATCH_TYPE_MEASUREMENT_LIST_FOR_USER -> {
+                val targetUserIdFromUri = try {
+                    ContentUris.parseId(uri).toInt()
+                } catch (e: NumberFormatException) {
+                    LogManager.e(TAG, "Invalid User ID in URI for measurement update: $uri", e)
+                    return 0 // Return 0 rows affected
+                }
+
+                // DATETIME from ContentValues is used to identify the measurement to update.
+                // It should NOT be used to change the timestamp of an existing measurement,
+                // as that changes its identity. If you need to change a measurement's time,
+                // it's a more complex operation (delete old, insert new, or a dedicated function).
+                val datetimeToUpdate = values.getAsLong(MeasurementColumns.DATETIME)
+                if (datetimeToUpdate == null) {
+                    LogManager.e(
+                        TAG,
+                        "Cannot update measurement: '${MeasurementColumns.DATETIME}' is missing from ContentValues. " +
+                                "This field is used to identify the measurement to update."
+                    )
+                    return 0
+                }
+
+                // Check if _ID in ContentValues mismatches the one in URI
+                if (values.containsKey(MeasurementColumns._ID)) {
+                    val idFromCV = values.getAsInteger(MeasurementColumns._ID)
+                    if (idFromCV != null && idFromCV != targetUserIdFromUri) {
+                        LogManager.w(
+                            TAG,
+                            "_ID in ContentValues ($idFromCV) mismatches _ID in URI ($targetUserIdFromUri) for update. " +
+                                    "Operation will proceed for _ID from URI."
+                        )
+                    }
+                }
+
+                // Perform database operations within runBlocking
+                rowsAffected = runBlocking {
+                    try {
+                        val allMeasurementTypes = databaseRepository.getAllMeasurementTypes().first()
+                        val typeIdMap = allMeasurementTypes.associate { it.key to it.id }
+
+                        // Find the existing measurement with its values
+                        val existingMeasurementWithValues = databaseRepository
+                            .getMeasurementsWithValuesForUser(targetUserIdFromUri)
+                            .first()
+                            .find { it.measurement.timestamp == datetimeToUpdate }
+
+                        if (existingMeasurementWithValues == null) {
+                            LogManager.d(
+                                TAG,
+                                "No measurement found to update for user $targetUserIdFromUri at datetime $datetimeToUpdate."
+                            )
+                            return@runBlocking 0 // Return 0 from runBlocking
+                        }
+
+                        val measurementToUpdate = existingMeasurementWithValues.measurement
+                        var anyChangeMadeToValues = false
+
+                        // Helper function to process updates for a specific measurement type
+                        suspend fun processValueUpdate(cvKey: String, typeKey: MeasurementTypeKey) {
+                            if (values.containsKey(cvKey)) {
+                                val newValue = values.getAsFloat(cvKey) // Can be null if key exists but value is to be cleared/deleted
+                                val typeId = typeIdMap[typeKey]
+
+                                if (typeId == null) {
+                                    LogManager.w(
+                                        TAG,
+                                        "MeasurementTypeKey '$typeKey' (for CV key '$cvKey') not found in typeIdMap. Cannot update/delete value."
+                                    )
+                                    return // Skip this value
+                                }
+
+                                val existingValueWithType =
+                                    existingMeasurementWithValues.values.find { it.type.id == typeId }
+
+                                if (newValue != null) { // New value is provided (update or insert)
+                                    if (existingValueWithType != null) { // Value exists, try to update
+                                        if (existingValueWithType.value.floatValue != newValue) {
+                                            val updatedDbValue = existingValueWithType.value.copy(floatValue = newValue)
+                                            databaseRepository.updateMeasurementValue(updatedDbValue)
+                                            anyChangeMadeToValues = true
+                                            LogManager.d(TAG, "Updated $typeKey for measurement ${measurementToUpdate.id} to $newValue")
+                                        }
+                                    } else { // Value doesn't exist for this type, insert new
+                                        val newDbValue = MeasurementValue(
+                                            // id = 0, // Room will generate
+                                            measurementId = measurementToUpdate.id,
+                                            typeId = typeId,
+                                            floatValue = newValue
+                                        )
+                                        databaseRepository.insertMeasurementValue(newDbValue)
+                                        anyChangeMadeToValues = true
+                                        LogManager.d(TAG, "Inserted new $typeKey for measurement ${measurementToUpdate.id} with value $newValue")
+                                    }
+                                } else { // New value is null (ContentValues has the key, but its value is null) - implies delete
+                                    existingValueWithType?.value?.let { valueToDelete ->
+                                        // Special handling for essential values like WEIGHT if deletion is unintended by API design
+                                        if (typeKey == MeasurementTypeKey.WEIGHT) {
+                                            LogManager.w(
+                                                TAG,
+                                                "Attempt to delete WEIGHT value via update (by passing null for '${MeasurementColumns.WEIGHT}'). " +
+                                                        "Weight value for measurement ID ${valueToDelete.measurementId} will be removed. " +
+                                                        "Ensure this is intended as a measurement usually requires a weight."
+                                            )
+                                        }
+                                        databaseRepository.deleteMeasurementValueById(valueToDelete.id) // Assuming delete by ID
+                                        anyChangeMadeToValues = true
+                                        LogManager.d(TAG, "Deleted $typeKey (ID: ${valueToDelete.id}) for measurement ${measurementToUpdate.id}")
+                                    }
+                                }
+                            }
+                        }
+
+                        // Process updates for all relevant measurement types
+                        processValueUpdate(MeasurementColumns.WEIGHT, MeasurementTypeKey.WEIGHT)
+                        processValueUpdate(MeasurementColumns.BODY_FAT, MeasurementTypeKey.BODY_FAT)
+                        processValueUpdate(MeasurementColumns.WATER, MeasurementTypeKey.WATER)
+                        processValueUpdate(MeasurementColumns.MUSCLE, MeasurementTypeKey.MUSCLE)
+
+                        if (anyChangeMadeToValues) {
+                            // If any MeasurementValue changed, recalculate derived values
+                            databaseRepository.recalculateDerivedValuesForMeasurement(measurementToUpdate.id)
+                            LogManager.d(
+                                TAG,
+                                "Measurement values changed for user ${measurementToUpdate.userId}, " +
+                                        "original timestamp: ${existingMeasurementWithValues.measurement.timestamp}. Derived values recalculated."
+                            )
+                            return@runBlocking 1 // Return 1 row affected from runBlocking
+                        } else {
+                            LogManager.d(
+                                TAG,
+                                "No actual changes detected for measurement values for user $targetUserIdFromUri at datetime $datetimeToUpdate."
+                            )
+                            return@runBlocking 0 // Return 0 from runBlocking
+                        }
+
+                    } catch (e: Exception) {
+                        LogManager.e(
+                            TAG,
+                            "Error updating measurement for user $targetUserIdFromUri: ${e.message}",
+                            e
+                        )
+                        return@runBlocking 0 // Return 0 from runBlocking on error
+                    }
+                }
+            }
+
+            else -> {
+                LogManager.w(TAG, "Update operation not supported for URI: $uri")
+                throw IllegalArgumentException("Unknown URI for update: $uri")
+            }
+        }
+
+        if (rowsAffected > 0) {
+            context!!.contentResolver.notifyChange(uri, null)
+        }
+
+        return rowsAffected
+    }
+
+
+    override fun delete(uri: Uri, selection: String?, selectionArgs: Array<String?>?): Int {
+        LogManager.w(TAG, "Delete operation is not supported by this provider.")
+        // To implement delete:
+        // 1. Identify user from URI (MATCH_TYPE_MEASUREMENT_LIST_FOR_USER implies user ID in URI)
+        // 2. Identify specific measurement to delete. This usually requires more than just user ID.
+        //    Commonly, the `selection` and `selectionArgs` would specify criteria like `DATETIME = ?`.
+        //    Or, you'd have a URI like "measurements/<user_id>/<measurement_id>" (MATCH_TYPE_SINGLE_MEASUREMENT).
+        // Example (conceptual):
+        /*
+        if (uriMatcher.match(uri) == MATCH_TYPE_MEASUREMENT_LIST_FOR_USER) {
+            val userId = ContentUris.parseId(uri).toInt()
+            if (selection != null && selectionArgs != null) {
+                // Parse selection to find the measurement (e.g., by datetime)
+                // val measurementToDelete = databaseRepository.findMeasurementByCriteria(userId, selection, selectionArgs)
+                // if (measurementToDelete != null) {
+                //     databaseRepository.deleteMeasurementWithValues(measurementToDelete)
+                //     rowsAffected = 1
+                //     context!!.contentResolver.notifyChange(uri, null)
+                // }
+            }
+        }
+        */
+        throw UnsupportedOperationException("Delete not supported by this provider")
+    }
+
+    companion object {
+        private val uriMatcher = UriMatcher(UriMatcher.NO_MATCH)
+        private const val API_VERSION = 1
+        val AUTHORITY = BuildConfig.APPLICATION_ID + ".provider"
+
+        private const val MATCH_TYPE_META = 1
+        private const val MATCH_TYPE_USER_LIST = 2 // content://<authority>/users
+        // content://<authority>/measurements/<user_id> (for list of measurements for a user)
+        private const val MATCH_TYPE_MEASUREMENT_LIST_FOR_USER = 3
+
+        init {
+            uriMatcher.addURI(AUTHORITY, "meta", MATCH_TYPE_META)
+            uriMatcher.addURI(AUTHORITY, "users", MATCH_TYPE_USER_LIST)
+            // The '#' wildcard matches a number (user ID in this case)
+            uriMatcher.addURI(AUTHORITY, "measurements/#", MATCH_TYPE_MEASUREMENT_LIST_FOR_USER)
+        }
+    }
+}

android_app/app/src/main/java/com/health/openscale/ui/screen/SharedViewModel.kt

@@ -17,17 +17,25 @@
  */
 package com.health.openscale.ui.screen
 
+import android.app.Application
+import android.content.ComponentName
+import android.content.Intent
 import androidx.annotation.StringRes
 import androidx.compose.material3.SnackbarDuration
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.core.content.ContextCompat
+import androidx.core.graphics.values
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.application
 import androidx.lifecycle.viewModelScope
 import com.health.openscale.R
+import com.health.openscale.core.bluetooth.data.ScaleMeasurement
 import com.health.openscale.core.data.InputFieldType
 import com.health.openscale.core.data.Measurement
 import com.health.openscale.core.data.MeasurementType
+import com.health.openscale.core.data.MeasurementTypeKey
 import com.health.openscale.core.data.MeasurementValue
 import com.health.openscale.core.data.TimeRangeFilter
 import com.health.openscale.core.data.Trend
@@ -57,6 +65,7 @@ import kotlinx.coroutines.flow.onStart
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
 import java.util.Calendar
+import java.util.Date
 
 private const val TAG = "SharedViewModel"
 
@@ -121,6 +130,7 @@ data class EnrichedMeasurement(
  */
 @OptIn(ExperimentalCoroutinesApi::class)
 class SharedViewModel(
+    private val application: Application,
     val databaseRepository: DatabaseRepository,
     val userSettingRepository: UserSettingsRepository
 ) : ViewModel() {
@@ -313,6 +323,9 @@ class SharedViewModel(
                             databaseRepository.insertMeasurementValue(value.copy(measurementId = measurementToSave.id))
                         }
                     }
+
+                    triggerSyncUpdateMeasurement(measurementToSave, valuesToSave, "com.health.openscale.sync")
+                    triggerSyncUpdateMeasurement(measurementToSave, valuesToSave,"com.health.openscale.sync.oss")
                     LogManager.i(TAG, "Measurement ID ${measurementToSave.id} and its values update process completed by ViewModel. (ViewModel Result)")
                     showSnackbar(messageResId = R.string.success_measurement_updated)
                 } else {
@@ -321,6 +334,8 @@ class SharedViewModel(
                     valuesToSave.forEach { value ->
                         databaseRepository.insertMeasurementValue(value.copy(measurementId = newMeasurementId))
                     }
+                    triggerSyncInsertMeasurement(measurementToSave, valuesToSave,"com.health.openscale.sync")
+                    triggerSyncInsertMeasurement(measurementToSave, valuesToSave,"com.health.openscale.sync.oss")
                     LogManager.i(TAG, "New measurement insertion process completed by ViewModel with ID: $newMeasurementId. (ViewModel Result)")
                     showSnackbar(messageResId = R.string.success_measurement_saved)
                 }
@@ -337,6 +352,8 @@ class SharedViewModel(
             try {
                 LogManager.d(TAG, "Preparing to delete measurement ID: ${measurement.id}. (ViewModel Logic)")
                 databaseRepository.deleteMeasurement(measurement)
+                triggerSyncDeleteMeasurement(Date(measurement.timestamp), "com.health.openscale.sync")
+                triggerSyncDeleteMeasurement(Date(measurement.timestamp), "com.health.openscale.sync.oss")
                 LogManager.i(TAG, "Measurement ID ${measurement.id} deletion process completed by ViewModel. (ViewModel Result)")
                 showSnackbar(messageResId = R.string.success_measurement_deleted)
                 if (_currentMeasurementId.value == measurement.id) {
@@ -600,6 +617,130 @@ class SharedViewModel(
         }
         LogManager.i(TAG, "ViewModel initialization complete. (Lifecycle Event)")
     }
+
+    private fun triggerSyncInsertMeasurement(
+        measurementToSave: Measurement,
+        valuesToSave: List<MeasurementValue>,
+        pkgName: String
+    ) {
+        val intent = Intent()
+        intent.setComponent(
+            ComponentName(
+                pkgName,
+                "com.health.openscale.sync.core.service.SyncService"
+            )
+        )
+
+        intent.putExtra("mode", "insert")
+        intent.putExtra("userId", measurementToSave.userId)
+        intent.putExtra("date", measurementToSave.timestamp)
+
+        var weightValue: Float? = null
+        var fatValue: Float? = null
+        var waterValue: Float? = null
+        var muscleValue: Float? = null
+
+        val idToTypeKeyMap = MeasurementTypeKey.values().associateBy { it.id }
+
+        for (valueEntry in valuesToSave) {
+            when (idToTypeKeyMap[valueEntry.typeId]) {
+                MeasurementTypeKey.WEIGHT -> weightValue = valueEntry.floatValue
+                MeasurementTypeKey.BODY_FAT -> fatValue = valueEntry.floatValue
+                MeasurementTypeKey.WATER -> waterValue = valueEntry.floatValue
+                MeasurementTypeKey.MUSCLE -> muscleValue = valueEntry.floatValue
+                else -> { }
+            }
+        }
+
+        weightValue?.let { intent.putExtra("weight", it) }
+        fatValue?.let { intent.putExtra("fat", it) }
+        waterValue?.let { intent.putExtra("water", it) }
+        muscleValue?.let { intent.putExtra("muscle", it) }
+
+        LogManager.d(
+            TAG, "SyncService for INSERT started for pkg: $pkgName. " +
+                    "UserId: ${measurementToSave.userId}, Date: ${measurementToSave.timestamp}, " +
+                    "Weight: $weightValue, Fat: $fatValue, Water: $waterValue, Muscle: $muscleValue"
+        )
+
+        ContextCompat.startForegroundService(application.applicationContext, intent)
+    }
+
+    private fun triggerSyncUpdateMeasurement(
+        measurementToSave: Measurement,
+        valuesToSave: List<MeasurementValue>,
+        pkgName: String
+    ) {
+        val intent = Intent()
+        intent.setComponent(
+            ComponentName(
+                pkgName,
+                "com.health.openscale.sync.core.service.SyncService"
+            )
+        )
+
+        intent.putExtra("mode", "update")
+        intent.putExtra("userId", measurementToSave.userId)
+        intent.putExtra("date", measurementToSave.timestamp)
+
+        var weightValue: Float? = null
+        var fatValue: Float? = null
+        var waterValue: Float? = null
+        var muscleValue: Float? = null
+
+        val idToTypeKeyMap = MeasurementTypeKey.values().associateBy { it.id }
+
+        for (valueEntry in valuesToSave) {
+            when (idToTypeKeyMap[valueEntry.typeId]) {
+                MeasurementTypeKey.WEIGHT -> weightValue = valueEntry.floatValue
+                MeasurementTypeKey.BODY_FAT -> fatValue = valueEntry.floatValue
+                MeasurementTypeKey.WATER -> waterValue = valueEntry.floatValue
+                MeasurementTypeKey.MUSCLE -> muscleValue = valueEntry.floatValue
+                else -> { }
+            }
+        }
+
+        weightValue?.let { intent.putExtra("weight", it) }
+        fatValue?.let { intent.putExtra("fat", it) }
+        waterValue?.let { intent.putExtra("water", it) }
+        muscleValue?.let { intent.putExtra("muscle", it) }
+
+        LogManager.d(
+            TAG, "SyncService for UPDATE started for pkg: $pkgName. " +
+                    "UserId: ${measurementToSave.userId}, Date: ${measurementToSave.timestamp}, " +
+                    "Weight: $weightValue, Fat: $fatValue, Water: $waterValue, Muscle: $muscleValue"
+        )
+
+        ContextCompat.startForegroundService(application.applicationContext, intent)
+    }
+
+
+    private fun triggerSyncDeleteMeasurement(date: Date, pkgName: String) {
+        val intent = Intent()
+        intent.setComponent(
+            ComponentName(
+                pkgName,
+                "com.health.openscale.sync.core.service.SyncService"
+            )
+        )
+        intent.putExtra("mode", "delete")
+        intent.putExtra("date", date.getTime())
+        ContextCompat.startForegroundService(application.applicationContext, intent)
+        LogManager.d(TAG, "SyncService for DELETE started for pkg: $pkgName")
+    }
+
+    private fun triggerSyncClearMeasurements(pkgName: String) {
+        val intent = Intent()
+        intent.setComponent(
+            ComponentName(
+                pkgName,
+                "com.health.openscale.sync.core.service.SyncService"
+            )
+        )
+        intent.putExtra("mode", "clear")
+        ContextCompat.startForegroundService(application.applicationContext, intent)
+        LogManager.d(TAG, "SyncService for CLEAR started for pkg: $pkgName")
+    }
 }
 
 /**

android_app/app/src/main/java/com/health/openscale/ui/screen/bluetooth/BluetoothViewModel.kt

@@ -79,12 +79,12 @@ enum class ConnectionStatus {
  * This ViewModel also manages user context relevant to Bluetooth operations and exposes
  * StateFlows for UI observation.
  *
- * @param context The application context.
+ * @param application The application context.
  * @param sharedViewModel A [SharedViewModel] instance for accessing shared resources like
  *                        repositories and for displaying global UI messages (e.g., Snackbars).
  */
 class BluetoothViewModel(
-    private val context: Application,
+    private val application: Application,
     val sharedViewModel: SharedViewModel
 ) : ViewModel() {
 
@@ -103,14 +103,14 @@ class BluetoothViewModel(
     private var currentAppUserId: Int = 0
 
     // --- Dependencies (ScaleFactory is passed to managers) ---
-    private val scaleFactory = ScaleFactory(context.applicationContext, databaseRepository)
+    private val scaleFactory = ScaleFactory(application.applicationContext, databaseRepository)
 
     // --- BluetoothScannerManager (manages device scanning) ---
-    private val bluetoothScannerManager = BluetoothScannerManager(context, viewModelScope, scaleFactory)
+    private val bluetoothScannerManager = BluetoothScannerManager(application, viewModelScope, scaleFactory)
 
     // --- BluetoothConnectionManager (manages device connection and data events) ---
     private val bluetoothConnectionManager = BluetoothConnectionManager(
-        context = context.applicationContext,
+        context = application.applicationContext,
         scope = viewModelScope,
         scaleFactory = scaleFactory,
         databaseRepository = databaseRepository,
@@ -483,13 +483,13 @@ class BluetoothViewModel(
      */
     private fun checkInitialPermissions(): Boolean {
         return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
-            ContextCompat.checkSelfPermission(context, Manifest.permission.BLUETOOTH_SCAN) == PackageManager.PERMISSION_GRANTED &&
+            ContextCompat.checkSelfPermission(application, Manifest.permission.BLUETOOTH_SCAN) == PackageManager.PERMISSION_GRANTED &&
-                    ContextCompat.checkSelfPermission(context, Manifest.permission.BLUETOOTH_CONNECT) == PackageManager.PERMISSION_GRANTED
+                    ContextCompat.checkSelfPermission(application, Manifest.permission.BLUETOOTH_CONNECT) == PackageManager.PERMISSION_GRANTED
         } else {
             // For older Android versions (below S)
-            ContextCompat.checkSelfPermission(context, Manifest.permission.BLUETOOTH) == PackageManager.PERMISSION_GRANTED &&
+            ContextCompat.checkSelfPermission(application, Manifest.permission.BLUETOOTH) == PackageManager.PERMISSION_GRANTED &&
-                    ContextCompat.checkSelfPermission(context, Manifest.permission.BLUETOOTH_ADMIN) == PackageManager.PERMISSION_GRANTED &&
+                    ContextCompat.checkSelfPermission(application, Manifest.permission.BLUETOOTH_ADMIN) == PackageManager.PERMISSION_GRANTED &&
-                    ContextCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED
+                    ContextCompat.checkSelfPermission(application, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED
         }
     }
 
@@ -510,7 +510,7 @@ class BluetoothViewModel(
      * @return `true` if Bluetooth is enabled, `false` otherwise.
      */
     fun isBluetoothEnabled(): Boolean {
-        val bluetoothManager = context.getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager?
+        val bluetoothManager = application.getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager?
         val isEnabled = bluetoothManager?.adapter?.isEnabled ?: false
         // LogManager.v(TAG, "Bluetooth enabled status check: $isEnabled") // Potentially too verbose for frequent checks
         return isEnabled

android_app/app/src/main/res/values-de/strings.xml

@@ -372,4 +372,7 @@
     <string name="bluetooth_scale_info_step_on_for_reference">Bitte stellen Sie sich barfuß auf die Waage für Referenzmessungen.</string>
     <string name="bluetooth_scale_info_measuring_weight">Gewichtsmessung: %.2f</string>
     <string name="bluetooth_scale_error_max_users_reached">Maximale Anzahl gleichzeitiger Waagenbenutzer erreicht.</string>
+
+    <string name="permission_read_write_data_description">Auslesen der openScale Daten, inkl. Benutzerinformationen und aller gespeicherten Messungen</string>
+    <string name="permission_read_write_data_label">Lese- und Schreibzugriff auf openScale Daten</string>
 </resources>

android_app/app/src/main/res/values/strings.xml

@@ -374,4 +374,7 @@
     <string name="bluetooth_scale_info_measuring_weight">Measuring weight: %.2f</string>
     <string name="bluetooth_scale_error_max_users_reached">Max. number of concurrent scale users reached</string>
 
+    <string name="permission_read_write_data_description">read/write openScale data, including user information and all saved measurements</string>
+    <string name="permission_read_write_data_label">Read and Write openScale data</string>
+
 </resources>