Expose time of next backup in UI

to help debugging scheduling issues

app/src/main/java/com/stevesoltys/seedvault/settings/SettingsFragment.kt

@@ -140,7 +140,10 @@ class SettingsFragment : PreferenceFragmentCompat() {
         super.onViewCreated(view, savedInstanceState)
 
         viewModel.lastBackupTime.observe(viewLifecycleOwner) { time ->
-            setAppBackupStatusSummary(time)
+            setAppBackupStatusSummary(time, viewModel.nextScheduleTimeMillis.value)
+        }
+        viewModel.nextScheduleTimeMillis.observe(viewLifecycleOwner) { time ->
+            setAppBackupStatusSummary(viewModel.lastBackupTime.value, time)
         }
 
         val backupFiles: Preference = findPreference("backup_files")!!
@@ -159,6 +162,10 @@ class SettingsFragment : PreferenceFragmentCompat() {
         setBackupEnabledState()
         setBackupLocationSummary()
         setAutoRestoreState()
+        setAppBackupStatusSummary(
+            lastBackupInMillis = viewModel.lastBackupTime.value,
+            nextScheduleTimeMillis = viewModel.nextScheduleTimeMillis.value,
+        )
     }
 
     override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
@@ -244,10 +251,42 @@ class SettingsFragment : PreferenceFragmentCompat() {
         backupLocation.summary = storage?.name ?: getString(R.string.settings_backup_location_none)
     }
 
-    private fun setAppBackupStatusSummary(lastBackupInMillis: Long) {
+    private fun setAppBackupStatusSummary(
+        lastBackupInMillis: Long?,
+        nextScheduleTimeMillis: Long?,
+    ) {
+        val sb = StringBuilder()
+        if (lastBackupInMillis != null) {
             // set time of last backup
             val lastBackup = lastBackupInMillis.toRelativeTime(requireContext())
-        backupStatus.summary = getString(R.string.settings_backup_status_summary, lastBackup)
+            sb.append(getString(R.string.settings_backup_status_summary, lastBackup))
+        }
+        if (nextScheduleTimeMillis != null) {
+            // insert linebreak, if we have text before
+            if (sb.isNotEmpty()) sb.append("\n")
+            // set time of next backup
+            when (nextScheduleTimeMillis) {
+                -1L -> {
+                    val text = getString(R.string.settings_backup_last_backup_never)
+                    sb.append(getString(R.string.settings_backup_status_next_backup, text))
+                }
+
+                Long.MAX_VALUE -> {
+                    val text = if (backupManager.isBackupEnabled) {
+                        getString(R.string.notification_title)
+                    } else {
+                        getString(R.string.settings_backup_last_backup_never)
+                    }
+                    sb.append(getString(R.string.settings_backup_status_next_backup, text))
+                }
+
+                else -> {
+                    val text = nextScheduleTimeMillis.toRelativeTime(requireContext())
+                    sb.append(getString(R.string.settings_backup_status_next_backup_estimate, text))
+                }
+            }
+        }
+        backupStatus.summary = sb.toString()
     }
 
     private fun onEnablingStorageBackup() {

app/src/main/java/com/stevesoltys/seedvault/settings/SettingsViewModel.kt

@@ -22,9 +22,11 @@ import androidx.core.content.ContextCompat.startForegroundService
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.liveData
+import androidx.lifecycle.map
 import androidx.lifecycle.switchMap
 import androidx.lifecycle.viewModelScope
 import androidx.recyclerview.widget.DiffUtil.calculateDiff
+import androidx.work.WorkManager
 import com.stevesoltys.seedvault.R
 import com.stevesoltys.seedvault.crypto.KeyManager
 import com.stevesoltys.seedvault.metadata.MetadataManager
@@ -35,6 +37,7 @@ import com.stevesoltys.seedvault.storage.StorageBackupService.Companion.EXTRA_ST
 import com.stevesoltys.seedvault.ui.RequireProvisioningViewModel
 import com.stevesoltys.seedvault.ui.notification.BackupNotificationManager
 import com.stevesoltys.seedvault.worker.AppBackupWorker
+import com.stevesoltys.seedvault.worker.AppBackupWorker.Companion.UNIQUE_WORK_NAME
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -61,6 +64,7 @@ internal class SettingsViewModel(
     private val contentResolver = app.contentResolver
     private val connectivityManager: ConnectivityManager? =
         app.getSystemService(ConnectivityManager::class.java)
+    private val workManager = WorkManager.getInstance(app)
 
     override val isRestoreOperation = false
 
@@ -68,6 +72,11 @@ internal class SettingsViewModel(
     val backupPossible: LiveData<Boolean> = mBackupPossible
 
     internal val lastBackupTime = metadataManager.lastBackupTime
+    val nextScheduleTimeMillis =
+        workManager.getWorkInfosForUniqueWorkLiveData(UNIQUE_WORK_NAME).map {
+            if (it.size > 0) it[0].nextScheduleTimeMillis
+            else -1L
+        }
 
     private val mAppStatusList = lastBackupTime.switchMap {
         // updates app list when lastBackupTime changes

app/src/main/java/com/stevesoltys/seedvault/worker/AppBackupWorker.kt

@@ -35,7 +35,7 @@ class AppBackupWorker(
 
     companion object {
         private val TAG = AppBackupWorker::class.simpleName
-        private const val UNIQUE_WORK_NAME = "com.stevesoltys.seedvault.APP_BACKUP"
+        internal const val UNIQUE_WORK_NAME = "com.stevesoltys.seedvault.APP_BACKUP"
         private const val TAG_NOW = "com.stevesoltys.seedvault.TAG_NOW"
 
         fun schedule(context: Context, existingWorkPolicy: ExistingPeriodicWorkPolicy = UPDATE) {

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

@@ -30,6 +30,8 @@
     <string name="settings_backup_apk_dialog_disable">Disable app backup</string>
     <string name="settings_backup_status_title">Backup status</string>
     <string name="settings_backup_status_summary">Last backup: %1$s</string>
+    <string name="settings_backup_status_next_backup">Next backup: %1$s</string>
+    <string name="settings_backup_status_next_backup_estimate">Next backup (estimate): %1$s</string>
     <string name="settings_backup_exclude_apps">Exclude apps</string>
     <string name="settings_backup_now">Backup now</string>
     <string name="settings_category_storage">Storage backup (beta)</string>