Decouple ChannelScreen from UIViewModel (#3295)

app/src/main/java/com/geeksville/mesh/ui/Main.kt

@@ -390,9 +390,9 @@ fun MainScreen(uIViewModel: UIViewModel = hiltViewModel(), scanModel: BTScanMode
                     modifier = Modifier.fillMaxSize().recalculateWindowInsets().safeDrawingPadding().imePadding(),
                 ) {
                     contactsGraph(navController)
-                    nodesGraph(navController, uiViewModel = uIViewModel)
+                    nodesGraph(navController)
                     mapGraph(navController)
-                    channelsGraph(navController, uiViewModel = uIViewModel)
+                    channelsGraph(navController)
                     connectionsGraph(navController)
                     settingsGraph(navController)
                 }

app/src/main/java/com/geeksville/mesh/ui/sharing/Channel.kt

@@ -21,6 +21,7 @@ import android.Manifest
 import android.content.ClipData
 import android.net.Uri
 import android.os.RemoteException
+import android.widget.Toast
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.border
@@ -74,6 +75,7 @@ import androidx.compose.ui.graphics.painter.BitmapPainter
 import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.platform.ClipEntry
 import androidx.compose.ui.platform.LocalClipboard
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalFocusManager
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
@@ -92,7 +94,6 @@ import com.geeksville.mesh.ConfigProtos
 import com.geeksville.mesh.MeshUtilApplication.Companion.analytics
 import com.geeksville.mesh.channelSet
 import com.geeksville.mesh.copy
-import com.geeksville.mesh.model.UIViewModel
 import com.geeksville.mesh.navigation.ConfigRoute
 import com.geeksville.mesh.navigation.getNavRouteFrom
 import com.geeksville.mesh.ui.settings.radio.RadioConfigViewModel
@@ -124,7 +125,7 @@ import timber.log.Timber
 @Suppress("LongMethod", "CyclomaticComplexMethod")
 @Composable
 fun ChannelScreen(
-    viewModel: UIViewModel = hiltViewModel(),
+    viewModel: ChannelViewModel = hiltViewModel(),
     radioConfigViewModel: RadioConfigViewModel = hiltViewModel(),
     onNavigate: (Route) -> Unit,
 ) {
@@ -175,10 +176,13 @@ fun ChannelScreen(
             settings.addAll(result)
         }
 
+    val context = LocalContext.current
     val barcodeLauncher =
         rememberLauncherForActivityResult(ScanContract()) { result ->
             if (result.contents != null) {
-                viewModel.requestChannelUrl(result.contents.toUri())
+                viewModel.requestChannelUrl(result.contents.toUri()) {
+                    Toast.makeText(context, R.string.channel_invalid, Toast.LENGTH_SHORT).show()
+                }
             }
         }
 
@@ -210,12 +214,12 @@ fun ChannelScreen(
             viewModel.setChannels(newChannelSet)
             // Since we are writing to DeviceConfig, that will trigger the rest of the GUI update (QR code etc)
         } catch (ex: RemoteException) {
-            Timber.e("ignoring channel problem", ex)
+            Timber.e(ex, "ignoring channel problem")
 
             channelSet = channels // Throw away user edits
 
             // Tell the user to try again
-            viewModel.showSnackBar(R.string.cant_change_no_radio)
+            Toast.makeText(context, R.string.cant_change_no_radio, Toast.LENGTH_SHORT).show()
         }
     }
 
@@ -282,7 +286,11 @@ fun ChannelScreen(
             EditChannelUrl(
                 enabled = enabled,
                 channelUrl = selectedChannelSet.getChannelUrl(shouldAdd = shouldAddChannelsState),
-                onConfirm = viewModel::requestChannelUrl,
+                onConfirm = {
+                    viewModel.requestChannelUrl(it) {
+                        Toast.makeText(context, R.string.channel_invalid, Toast.LENGTH_SHORT).show()
+                    }
+                },
             )
         }
         item {

app/src/main/java/com/geeksville/mesh/ui/sharing/ChannelViewModel.kt

@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2025 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 com.geeksville.mesh.ui.sharing
+
+import android.net.Uri
+import android.os.RemoteException
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.geeksville.mesh.AppOnlyProtos
+import com.geeksville.mesh.ChannelProtos
+import com.geeksville.mesh.ConfigProtos.Config
+import com.geeksville.mesh.LocalOnlyProtos.LocalConfig
+import com.geeksville.mesh.channelSet
+import com.geeksville.mesh.config
+import com.geeksville.mesh.copy
+import com.geeksville.mesh.model.getChannelList
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import org.meshtastic.core.data.repository.RadioConfigRepository
+import org.meshtastic.core.model.util.toChannelSet
+import org.meshtastic.core.service.ServiceRepository
+import timber.log.Timber
+import javax.inject.Inject
+
+@HiltViewModel
+class ChannelViewModel
+@Inject
+constructor(
+    private val serviceRepository: ServiceRepository,
+    private val radioConfigRepository: RadioConfigRepository,
+) : ViewModel() {
+
+    val connectionState = serviceRepository.connectionState
+
+    val localConfig =
+        radioConfigRepository.localConfigFlow.stateIn(
+            viewModelScope,
+            SharingStarted.WhileSubscribed(5_000),
+            LocalConfig.getDefaultInstance(),
+        )
+
+    val channels =
+        radioConfigRepository.channelSetFlow.stateIn(
+            viewModelScope,
+            SharingStarted.WhileSubscribed(5_000),
+            channelSet {},
+        )
+
+    // managed mode disables all access to configuration
+    val isManaged: Boolean
+        get() = localConfig.value.device.isManaged || localConfig.value.security.isManaged
+
+    var txEnabled: Boolean
+        get() = localConfig.value.lora.txEnabled
+        set(value) {
+            updateLoraConfig { it.copy { txEnabled = value } }
+        }
+
+    var region: Config.LoRaConfig.RegionCode
+        get() = localConfig.value.lora.region
+        set(value) {
+            updateLoraConfig { it.copy { region = value } }
+        }
+
+    private val _requestChannelSet = MutableStateFlow<AppOnlyProtos.ChannelSet?>(null)
+    val requestChannelSet: StateFlow<AppOnlyProtos.ChannelSet?>
+        get() = _requestChannelSet
+
+    fun requestChannelUrl(url: Uri, onError: () -> Unit) = runCatching { _requestChannelSet.value = url.toChannelSet() }
+        .onFailure { ex ->
+            Timber.e(ex, "Channel url error")
+            onError()
+        }
+
+    /** Set the radio config (also updates our saved copy in preferences). */
+    fun setChannels(channelSet: AppOnlyProtos.ChannelSet) = viewModelScope.launch {
+        getChannelList(channelSet.settingsList, channels.value.settingsList).forEach(::setChannel)
+        radioConfigRepository.replaceAllSettings(channelSet.settingsList)
+
+        val newConfig = config { lora = channelSet.loraConfig }
+        if (localConfig.value.lora != newConfig.lora) setConfig(newConfig)
+    }
+
+    fun setChannel(channel: ChannelProtos.Channel) {
+        try {
+            serviceRepository.meshService?.setChannel(channel.toByteArray())
+        } catch (ex: RemoteException) {
+            Timber.e(ex, "Set channel error")
+        }
+    }
+
+    // Set the radio config (also updates our saved copy in preferences)
+    fun setConfig(config: Config) {
+        try {
+            serviceRepository.meshService?.setConfig(config.toByteArray())
+        } catch (ex: RemoteException) {
+            Timber.e(ex, "Set config error")
+        }
+    }
+
+    private inline fun updateLoraConfig(crossinline body: (Config.LoRaConfig) -> Config.LoRaConfig) {
+        val data = body(localConfig.value.lora)
+        setConfig(config { lora = data })
+    }
+}