feat: widget stack remembers its position across reboots

app/src/main/java/com/sameerasw/essentials/data/repository/WidgetStackRepository.kt

@@ -11,6 +11,7 @@ package com.sameerasw.essentials.data.repository
 
 import android.content.Context
 import android.content.SharedPreferences
+import androidx.core.content.edit
 import com.google.gson.Gson
 import com.google.gson.reflect.TypeToken
 import com.sameerasw.essentials.domain.model.WidgetStackConfig
@@ -43,6 +44,32 @@ class WidgetStackRepository(
 
     fun get(stackWidgetId: Int): WidgetStackConfig? = getAll().firstOrNull { it.stackWidgetId == stackWidgetId }
 
+    fun getPositions(): Map<Int, Int> {
+        val result = mutableMapOf<Int, Int>()
+        for ((key, value) in prefs.all) {
+            if (key.startsWith(KEY_POSITION_PREFIX) && value is Int) {
+                val id = key.removePrefix(KEY_POSITION_PREFIX).toIntOrNull() ?: continue
+                result[id] = value
+            }
+        }
+        return result
+    }
+
+    fun savePositions(positions: Map<Int, Int>) {
+        val toSave =
+            positions.filter { (id, pos) ->
+                val key = KEY_POSITION_PREFIX + id
+                val stored = if (prefs.contains(key)) prefs.getInt(key, 0) else null
+                stored != pos
+            }
+        if (toSave.isEmpty()) return
+        prefs.edit {
+            for ((id, pos) in toSave) {
+                putInt(KEY_POSITION_PREFIX + id, pos)
+            }
+        }
+    }
+
     fun save(config: WidgetStackConfig) =
         synchronized(LOCK) {
             write(getAll().filterNot { it.stackWidgetId == config.stackWidgetId } + config)
@@ -51,6 +78,7 @@ class WidgetStackRepository(
     fun delete(stackWidgetId: Int) =
         synchronized(LOCK) {
             write(getAll().filterNot { it.stackWidgetId == stackWidgetId })
+            prefs.edit { remove(KEY_POSITION_PREFIX + stackWidgetId) }
         }
 
     private fun write(stacks: List<WidgetStackConfig>) {
@@ -63,6 +91,7 @@ class WidgetStackRepository(
     companion object {
         private const val PREFS_NAME = "widget_stack_prefs"
         private const val KEY_STACKS = "stacks"
+        private const val KEY_POSITION_PREFIX = "position_"
         private val LOCK = Any()
         private var cachedJson: String? = null
         private var cachedStacks: List<WidgetStackConfig> = emptyList()

app/src/main/java/com/sameerasw/essentials/services/widgets/StackHost.kt

@@ -14,7 +14,7 @@ import android.appwidget.AppWidgetHostView
 import android.appwidget.AppWidgetManager
 import android.appwidget.AppWidgetProviderInfo
 import android.content.BroadcastReceiver
-import android.content.ComponentCallbacks
+import android.content.ComponentCallbacks2
 import android.content.Context
 import android.content.Intent
 import android.content.IntentFilter
@@ -102,20 +102,28 @@ object StackHost {
                 intent: Intent,
             ) {
                 when (intent.action) {
-                    Intent.ACTION_SCREEN_OFF -> cancelAllTimers()
+                    Intent.ACTION_SCREEN_OFF -> {
+                        cancelAllTimers()
+                        repository.savePositions(positions)
+                    }
+
                     Intent.ACTION_SCREEN_ON -> repository.getAll().forEach { scheduleTimer(it.stackWidgetId) }
                 }
             }
         }
 
     private val configurationCallbacks =
-        object : ComponentCallbacks {
+        object : ComponentCallbacks2 {
             override fun onConfigurationChanged(newConfig: Configuration) {
                 repository.getAll().forEach { StackWidgetProvider.forwardSize(appContext, it) }
             }
 
             @Deprecated("Deprecated in Java")
             override fun onLowMemory() {}
+
+            override fun onTrimMemory(level: Int) {
+                if (level >= ComponentCallbacks2.TRIM_MEMORY_BACKGROUND) repository.savePositions(positions)
+            }
         }
 
     fun startIfNeeded(context: Context) {
@@ -140,6 +148,9 @@ object StackHost {
             if (host == null) start(app)
             reveal(stackWidgetId)
             advance(stackWidgetId, delta)
+            positions[stackWidgetId]?.let { pos ->
+                repository.savePositions(mapOf(stackWidgetId to pos))
+            }
         }
     }
 
@@ -177,6 +188,7 @@ object StackHost {
             PeriodicWorkRequestBuilder<StackHostWorker>(15, TimeUnit.MINUTES).build(),
         )
         repository = WidgetStackRepository(context)
+        positions.putAll(StackPositions.restore(repository.getPositions(), repository.getAll()))
         host = CapturingWidgetHost(context).also { it.startListening() }
         removeOrphanedWidgets()
         attachOverlay()

app/src/main/java/com/sameerasw/essentials/services/widgets/StackPositions.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2026 sameerasw.com
+ * License: MIT License
+ *
+ * Feature Module: Background Services & Receivers
+ * File: StackPositions.kt
+ * Description: Restores and validates widget stack positions.
+ */
+
+package com.sameerasw.essentials.services.widgets
+
+import com.sameerasw.essentials.domain.model.WidgetStackConfig
+
+object StackPositions {
+    fun restore(
+        saved: Map<Int, Int>,
+        stacks: List<WidgetStackConfig>,
+    ): Map<Int, Int> =
+        buildMap {
+            for (stack in stacks) {
+                if (stack.hostedWidgetIds.isEmpty()) continue
+                val pos = saved[stack.stackWidgetId] ?: continue
+                put(stack.stackWidgetId, pos.coerceIn(0, stack.hostedWidgetIds.lastIndex))
+            }
+        }
+}

app/src/test/java/com/sameerasw/essentials/services/StackPositionsTest.kt

@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2026 sameerasw.com
+ * License: MIT License
+ *
+ * Feature Module: Unit Tests - Services
+ * File: StackPositionsTest.kt
+ * Description: Unit tests for StackPositions restore logic.
+ */
+
+package com.sameerasw.essentials.services
+
+import com.sameerasw.essentials.domain.model.WidgetStackConfig
+import com.sameerasw.essentials.services.widgets.StackPositions
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class StackPositionsTest {
+    @Test
+    fun keepsSavedPositionInRange() {
+        val stacks = listOf(WidgetStackConfig(stackWidgetId = 1, hostedWidgetIds = listOf(10, 11, 12)))
+        val saved = mapOf(1 to 1)
+        assertEquals(mapOf(1 to 1), StackPositions.restore(saved, stacks))
+    }
+
+    @Test
+    fun clampsSavedPositionAboveLastIndexToLastIndex() {
+        val stacks = listOf(WidgetStackConfig(stackWidgetId = 1, hostedWidgetIds = listOf(10, 11, 12)))
+        val saved = mapOf(1 to 5)
+        assertEquals(mapOf(1 to 2), StackPositions.restore(saved, stacks))
+    }
+
+    @Test
+    fun clampsNegativeSavedPositionToZero() {
+        val stacks = listOf(WidgetStackConfig(stackWidgetId = 1, hostedWidgetIds = listOf(10, 11, 12)))
+        val saved = mapOf(1 to -3)
+        assertEquals(mapOf(1 to 0), StackPositions.restore(saved, stacks))
+    }
+
+    @Test
+    fun dropsPositionsForStackIdsNotInStacks() {
+        val stacks = listOf(WidgetStackConfig(stackWidgetId = 1, hostedWidgetIds = listOf(10, 11)))
+        val saved = mapOf(1 to 1, 2 to 0, 99 to 3)
+        assertEquals(mapOf(1 to 1), StackPositions.restore(saved, stacks))
+    }
+
+    @Test
+    fun leavesOutStacksWithNoHostedWidgets() {
+        val stacks =
+            listOf(
+                WidgetStackConfig(stackWidgetId = 1, hostedWidgetIds = emptyList()),
+                WidgetStackConfig(stackWidgetId = 2, hostedWidgetIds = listOf(20)),
+            )
+        val saved = mapOf(1 to 0, 2 to 0)
+        assertEquals(mapOf(2 to 0), StackPositions.restore(saved, stacks))
+    }
+
+    @Test
+    fun leavesOutStacksWithNoSavedPosition() {
+        val stacks =
+            listOf(
+                WidgetStackConfig(stackWidgetId = 1, hostedWidgetIds = listOf(10, 11)),
+                WidgetStackConfig(stackWidgetId = 2, hostedWidgetIds = listOf(20, 21)),
+            )
+        val saved = mapOf(1 to 1)
+        assertEquals(mapOf(1 to 1), StackPositions.restore(saved, stacks))
+    }
+}