fix(widget): drive updates via debounced state observer (#5185)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: garthvh <1795163+garthvh@users.noreply.github.com>

feature/widget/src/main/kotlin/org/meshtastic/feature/widget/AndroidAppWidgetUpdater.kt

@@ -17,22 +17,48 @@
 package org.meshtastic.feature.widget
 
 import android.content.Context
+import androidx.glance.appwidget.GlanceAppWidgetManager
 import androidx.glance.appwidget.updateAll
 import co.touchlab.kermit.Logger
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.FlowPreview
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.flow.debounce
+import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.launch
 import org.koin.core.annotation.Single
 import org.meshtastic.core.repository.AppWidgetUpdater
 
+private const val WIDGET_UPDATE_DEBOUNCE_MS = 500L
+
 @Single
-class AndroidAppWidgetUpdater(private val context: Context) : AppWidgetUpdater {
+class AndroidAppWidgetUpdater(private val context: Context, stateProvider: LocalStatsWidgetStateProvider) :
+    AppWidgetUpdater {
+    private val scope = CoroutineScope(SupervisorJob() + Dispatchers.Default)
+
+    init {
+        // Observe state changes and trigger a widget re-render whenever the data changes.
+        // Glance compositions are ephemeral — the widget cannot self-update via collectAsState()
+        // alone, so we must call updateAll() externally to drive re-renders.
+        @OptIn(FlowPreview::class)
+        scope.launch {
+            stateProvider.state
+                .debounce(WIDGET_UPDATE_DEBOUNCE_MS)
+                .distinctUntilChanged { old, new -> old.copy(updateTimeMillis = 0) == new.copy(updateTimeMillis = 0) }
+                .collect { if (hasWidgetInstances()) updateAll() }
+        }
+    }
+
+    private suspend fun hasWidgetInstances(): Boolean =
+        GlanceAppWidgetManager(context).getGlanceIds(LocalStatsWidget::class.java).isNotEmpty()
+
     override suspend fun updateAll() {
-        // Kickstart the widget composition.
-        // The widget internally uses collectAsState() and its own sampled StateFlow
-        // to drive updates automatically without excessive IPC and recreation.
         @Suppress("TooGenericExceptionCaught")
         try {
             LocalStatsWidget().updateAll(context)
         } catch (e: Exception) {
-            co.touchlab.kermit.Logger.e(e) { "Failed to update widgets" }
+            Logger.e(e) { "Failed to update widgets" }
         }
     }
 }

feature/widget/src/main/kotlin/org/meshtastic/feature/widget/LocalStatsWidgetState.kt

@@ -76,8 +76,6 @@ data class LocalStatsWidgetUiState(
     val updateTimeMillis: Long = 0,
 )
 
-private const val WIDGET_SUBSCRIPTION_TIMEOUT_MS = 5_000L
-
 @Single
 class LocalStatsWidgetStateProvider(nodeRepository: NodeRepository, serviceRepository: ServiceRepository) {
     private val scope = CoroutineScope(Dispatchers.Default + SupervisorJob())
@@ -100,12 +98,7 @@ class LocalStatsWidgetStateProvider(nodeRepository: NodeRepository, serviceRepos
             .map { input ->
                 mapToUiState(input.connectionState, input.totalNodes, input.onlineNodes, input.stats, input.localNode)
             }
-            .distinctUntilChanged()
-            .stateIn(
-                scope = scope,
-                started = SharingStarted.WhileSubscribed(WIDGET_SUBSCRIPTION_TIMEOUT_MS),
-                initialValue = LocalStatsWidgetUiState(),
-            )
+            .stateIn(scope = scope, started = SharingStarted.Eagerly, initialValue = LocalStatsWidgetUiState())
 
     private data class StateInput(
         val connectionState: ConnectionState,

feature/widget/src/main/res/values/strings.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ 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/>.
+  -->
+<resources>
+    <string name="widget_local_stats_label">Meshtastic</string>
+</resources>

feature/widget/src/main/res/xml/widget_local_stats_info.xml

@@ -16,6 +16,7 @@
   ~ along with this program.  If not, see <https://www.gnu.org/licenses/>.
   -->
 <appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
+    android:label="@string/widget_local_stats_label"
     android:initialLayout="@layout/glance_default_loading_layout"
     android:previewLayout="@layout/widget_local_stats_preview"
     android:minWidth="110dp"