refactor(feature/node): Extract MetricsViewModel to commonMain

app/src/main/kotlin/org/meshtastic/app/navigation/NodesNavigation.kt

@@ -35,7 +35,7 @@ import kotlinx.coroutines.flow.Flow
 import org.jetbrains.compose.resources.StringResource
 import org.koin.compose.viewmodel.koinViewModel
 import org.meshtastic.app.map.node.NodeMapScreen
-import org.meshtastic.app.node.AndroidMetricsViewModel
+import org.meshtastic.feature.node.metrics.MetricsViewModel
 import org.meshtastic.app.ui.node.AdaptiveNodeListScreen
 import org.meshtastic.core.navigation.ContactsRoutes
 import org.meshtastic.core.navigation.NodeDetailRoutes
@@ -116,7 +116,7 @@ fun EntryProviderScope<NavKey>.nodeDetailGraph(
     }
 
     entry<NodeDetailRoutes.TracerouteLog> { args ->
-        val metricsViewModel = koinViewModel<AndroidMetricsViewModel>()
+        val metricsViewModel = koinViewModel<MetricsViewModel>()
         metricsViewModel.setNodeId(args.destNum)
 
         TracerouteLogScreen(
@@ -135,7 +135,7 @@ fun EntryProviderScope<NavKey>.nodeDetailGraph(
     }
 
     entry<NodeDetailRoutes.TracerouteMap> { args ->
-        val metricsViewModel = koinViewModel<AndroidMetricsViewModel>()
+        val metricsViewModel = koinViewModel<MetricsViewModel>()
         metricsViewModel.setNodeId(args.destNum)
 
         TracerouteMapScreen(
@@ -177,7 +177,7 @@ private inline fun <reified R : Route> EntryProviderScope<NavKey>.addNodeDetailS
     crossinline getDestNum: (R) -> Int,
 ) {
     entry<R> { args ->
-        val metricsViewModel = koinViewModel<AndroidMetricsViewModel>()
+        val metricsViewModel = koinViewModel<MetricsViewModel>()
         val destNum = getDestNum(args)
         metricsViewModel.setNodeId(destNum)
 

app/src/main/kotlin/org/meshtastic/app/node/AndroidMetricsViewModel.kt

@@ -1,113 +0,0 @@
-/*
- * Copyright (c) 2025-2026 Meshtastic LLC
- *
- * 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 org.meshtastic.app.node
-
-import android.app.Application
-import android.net.Uri
-import androidx.lifecycle.SavedStateHandle
-import androidx.lifecycle.viewModelScope
-import co.touchlab.kermit.Logger
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.withContext
-import org.koin.core.annotation.KoinViewModel
-import org.meshtastic.core.common.util.toDate
-import org.meshtastic.core.common.util.toInstant
-import org.meshtastic.core.data.repository.TracerouteSnapshotRepository
-import org.meshtastic.core.di.CoroutineDispatchers
-import org.meshtastic.core.repository.MeshLogRepository
-import org.meshtastic.core.repository.NodeRepository
-import org.meshtastic.core.repository.ServiceRepository
-import org.meshtastic.core.ui.util.AlertManager
-import org.meshtastic.feature.node.detail.NodeRequestActions
-import org.meshtastic.feature.node.domain.usecase.GetNodeDetailsUseCase
-import org.meshtastic.feature.node.metrics.MetricsViewModel
-import java.io.BufferedWriter
-import java.io.FileNotFoundException
-import java.io.FileWriter
-import java.text.SimpleDateFormat
-import java.util.Locale
-
-@KoinViewModel
-class AndroidMetricsViewModel(
-    savedStateHandle: SavedStateHandle,
-    private val app: Application,
-    dispatchers: CoroutineDispatchers,
-    meshLogRepository: MeshLogRepository,
-    serviceRepository: ServiceRepository,
-    nodeRepository: NodeRepository,
-    tracerouteSnapshotRepository: TracerouteSnapshotRepository,
-    nodeRequestActions: NodeRequestActions,
-    alertManager: AlertManager,
-    getNodeDetailsUseCase: GetNodeDetailsUseCase,
-) : MetricsViewModel(
-    savedStateHandle.get<Int>("destNum") ?: 0,
-    dispatchers,
-    meshLogRepository,
-    serviceRepository,
-    nodeRepository,
-    tracerouteSnapshotRepository,
-    nodeRequestActions,
-    alertManager,
-    getNodeDetailsUseCase,
-) {
-    override fun savePositionCSV(uri: Any) {
-        if (uri is Uri) {
-            savePositionCSVAndroid(uri)
-        }
-    }
-
-    private fun savePositionCSVAndroid(uri: Uri) = viewModelScope.launch(dispatchers.main) {
-        val positions = state.value.positionLogs
-        writeToUri(uri) { writer ->
-            writer.appendLine(
-                "\"date\",\"time\",\"latitude\",\"longitude\",\"altitude\",\"satsInView\",\"speed\",\"heading\"",
-            )
-
-            val dateFormat = SimpleDateFormat("\"yyyy-MM-dd\",\"HH:mm:ss\"", Locale.getDefault())
-
-            positions.forEach { position ->
-                val rxDateTime = dateFormat.format((position.time.toLong() * 1000L).toInstant().toDate())
-                val latitude = (position.latitude_i ?: 0) * 1e-7
-                val longitude = (position.longitude_i ?: 0) * 1e-7
-                val altitude = position.altitude
-                val satsInView = position.sats_in_view
-                val speed = position.ground_speed
-                val heading = "%.2f".format((position.ground_track ?: 0) * 1e-5)
-
-                writer.appendLine(
-                    "$rxDateTime,\"$latitude\",\"$longitude\",\"$altitude\",\"$satsInView\",\"$speed\",\"$heading\"",
-                )
-            }
-        }
-    }
-
-    private suspend inline fun writeToUri(uri: Uri, crossinline block: suspend (BufferedWriter) -> Unit) =
-        withContext(dispatchers.io) {
-            try {
-                app.contentResolver.openFileDescriptor(uri, "wt")?.use { parcelFileDescriptor ->
-                    FileWriter(parcelFileDescriptor.fileDescriptor).use { fileWriter ->
-                        BufferedWriter(fileWriter).use { writer -> block.invoke(writer) }
-                    }
-                }
-            } catch (ex: FileNotFoundException) {
-                Logger.e(ex) { "Can't write file error" }
-            }
-        }
-
-    override fun decodeBase64(base64: String): ByteArray =
-        android.util.Base64.decode(base64, android.util.Base64.DEFAULT)
-}

feature/node/src/androidMain/kotlin/org/meshtastic/feature/node/metrics/PositionLog.kt

@@ -16,6 +16,8 @@
  */
 package org.meshtastic.feature.node.metrics
 
+import org.meshtastic.core.common.util.toMeshtasticUri
+
 import android.app.Activity
 import android.content.Intent
 import androidx.activity.compose.rememberLauncherForActivityResult
@@ -119,7 +121,7 @@ fun PositionLogScreen(viewModel: MetricsViewModel, onNavigateUp: () -> Unit) {
     val exportPositionLauncher =
         rememberLauncherForActivityResult(ActivityResultContracts.StartActivityForResult()) {
             if (it.resultCode == Activity.RESULT_OK) {
-                it.data?.data?.let { uri -> viewModel.savePositionCSV(uri) }
+                it.data?.data?.let { uri -> viewModel.savePositionCSV(uri.toMeshtasticUri()) }
             }
         }
 

feature/node/src/commonMain/kotlin/org/meshtastic/feature/node/metrics/MetricsViewModel.kt

@@ -66,6 +66,13 @@ import org.meshtastic.proto.PortNum
 import org.meshtastic.proto.Telemetry
 import org.meshtastic.proto.Paxcount as ProtoPaxcount
 
+import org.meshtastic.core.repository.FileService
+import org.meshtastic.core.common.util.MeshtasticUri
+import kotlinx.datetime.Instant
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+import okio.ByteString.Companion.decodeBase64
+
 /**
  * ViewModel responsible for managing and graphing metrics (telemetry, signal strength, paxcount) for a specific node.
  */
@@ -81,6 +88,7 @@ open class MetricsViewModel(
     private val nodeRequestActions: NodeRequestActions,
     private val alertManager: AlertManager,
     private val getNodeDetailsUseCase: GetNodeDetailsUseCase,
+    private val fileService: FileService,
 ) : ViewModel() {
 
     private val nodeIdFromRoute: Int?
@@ -315,8 +323,30 @@ open class MetricsViewModel(
         Logger.d { "MetricsViewModel cleared" }
     }
 
-    open fun savePositionCSV(uri: Any) {
+    fun savePositionCSV(uri: MeshtasticUri) {
-        // To be implemented in platform-specific subclass
+        viewModelScope.launch(dispatchers.main) {
+            val positions = state.value.positionLogs
+            fileService.write(uri) { sink ->
+                sink.writeUtf8("\"date\",\"time\",\"latitude\",\"longitude\",\"altitude\",\"satsInView\",\"speed\",\"heading\"\n")
+
+                positions.forEach { position ->
+                    val localDateTime = Instant.fromEpochSeconds(position.time.toLong())
+                        .toLocalDateTime(TimeZone.currentSystemDefault())
+                    val rxDateTime = "\"${localDateTime.date}\",\"${localDateTime.time}\""
+                    
+                    val latitude = (position.latitude_i ?: 0) * 1e-7
+                    val longitude = (position.longitude_i ?: 0) * 1e-7
+                    val altitude = position.altitude
+                    val satsInView = position.sats_in_view
+                    val speed = position.ground_speed
+                    // Kotlin string format is available in common code on 1.9.20+ via String.format,
+                    // but we can just do basic string manipulation if needed.
+                    val heading = "%.2f".format((position.ground_track ?: 0) * 1e-5)
+
+                    sink.writeUtf8("$rxDateTime,\"$latitude\",\"$longitude\",\"$altitude\",\"$satsInView\",\"$speed\",\"$heading\"\n")
+                }
+            }
+        }
     }
 
     @Suppress("MagicNumber", "CyclomaticComplexMethod", "ReturnCount")
@@ -347,8 +377,7 @@ open class MetricsViewModel(
         return null
     }
 
-    protected open fun decodeBase64(base64: String): ByteArray {
+    protected fun decodeBase64(base64: String): ByteArray {
-        // To be overridden in platform-specific subclass or use KMP library
+        return base64.decodeBase64()?.toByteArray() ?: ByteArray(0)
-        return ByteArray(0)
     }
 }