Rename import/export buttons, display last backup

app/src/main/java/com/todoroo/astrid/backup/BackupConstants.kt

@@ -5,6 +5,7 @@
  */
 package com.todoroo.astrid.backup
 
+import androidx.documentfile.provider.DocumentFile
 import com.google.api.services.drive.model.File
 import org.tasks.time.DateTime
 import java.util.regex.Pattern
@@ -52,6 +53,10 @@ object BackupConstants {
         return getTimestampFromFilename(file.name) ?: file.modifiedTime.value
     }
 
+    fun getTimestamp(file: DocumentFile): Long {
+        return file.name?.let { getTimestampFromFilename(it) } ?: file.lastModified()
+    }
+
     private fun getTimestampFromFilename(name: String): Long? {
         return MATCHER
                 .matcher(name)

app/src/main/java/org/tasks/backup/BackupHelper.kt

@@ -0,0 +1,39 @@
+package org.tasks.backup
+
+import android.content.ContentResolver
+import android.content.Context
+import androidx.documentfile.provider.DocumentFile
+import com.todoroo.astrid.backup.BackupConstants
+import dagger.hilt.android.qualifiers.ApplicationContext
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import org.tasks.preferences.Preferences
+import java.io.File
+import javax.inject.Inject
+
+class BackupHelper @Inject constructor(
+        @param:ApplicationContext private val context: Context,
+        private val preferences: Preferences
+) {
+    suspend fun getLastBackup(): Long? {
+        val uri = preferences.backupDirectory
+        val timestamps: List<Long>? = withContext(Dispatchers.IO) {
+            when (uri?.scheme) {
+                ContentResolver.SCHEME_CONTENT -> {
+                    DocumentFile.fromTreeUri(context, uri)
+                            ?.listFiles()
+                            ?.filter { BackupConstants.isBackupFile(it.name!!) }
+                            ?.map { BackupConstants.getTimestamp(it) }
+                }
+                ContentResolver.SCHEME_FILE -> {
+                    File(uri.path!!)
+                            .listFiles()
+                            ?.filter { BackupConstants.isBackupFile(it.name) }
+                            ?.map { BackupConstants.getTimestamp(it) }
+                }
+                else -> emptyList()
+            }
+        }
+        return timestamps?.maxOrNull()
+    }
+}

app/src/main/java/org/tasks/preferences/fragments/Backups.kt

@@ -13,6 +13,7 @@ import dagger.hilt.android.AndroidEntryPoint
 import kotlinx.coroutines.launch
 import org.tasks.PermissionUtil
 import org.tasks.R
+import org.tasks.backup.BackupHelper
 import org.tasks.dialogs.ExportTasksDialog
 import org.tasks.dialogs.ImportTasksDialog
 import org.tasks.drive.DriveInvoker
@@ -42,6 +43,7 @@ class Backups : InjectingPreferenceFragment() {
     @Inject lateinit var googleAccountManager: GoogleAccountManager
     @Inject lateinit var locale: Locale
     @Inject lateinit var driveInvoker: DriveInvoker
+    @Inject lateinit var backupHelper: BackupHelper
 
     override fun getPreferenceXml() = R.xml.preferences_backups
 
@@ -97,14 +99,25 @@ class Backups : InjectingPreferenceFragment() {
             }
         }
 
-        val lastBackup = preferences.getLong(R.string.p_backups_android_backup_last, 0L)
+        lifecycleScope.launch {
+            findPreference(R.string.backup_BAc_export).summary =
+                    getString(
+                            R.string.last_backup,
+                            backupHelper.getLastBackup()
+                                    ?.takeIf { it > 0 }
+                                    ?.let { DateUtilities.getLongDateStringWithTime(it, locale) }
+                                    ?: getString(R.string.last_backup_never)
+                    )
+        }
+
+        val lastAndroidBackup = preferences.getLong(R.string.p_backups_android_backup_last, 0L)
         findPreference(R.string.p_backups_android_backup_enabled).summary =
                 getString(
                         R.string.last_backup,
-                        if (lastBackup == 0L) {
+                        if (lastAndroidBackup == 0L) {
                             getString(R.string.last_backup_never)
                         } else {
-                            DateUtilities.getLongDateStringWithTime(lastBackup, locale)
+                            DateUtilities.getLongDateStringWithTime(lastAndroidBackup, locale)
                         }
                 )
     }

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

@@ -6,8 +6,8 @@
   <string name="display_name">Display name</string>
   <string name="enter_filter_name">Enter filter name</string>
   <string name="backup_BPr_header">Backups</string>
-  <string name="backup_BAc_import">Import tasks</string>
-  <string name="backup_BAc_export">Export tasks</string>
+  <string name="backup_BAc_export">Backup now</string>
+  <string name="backup_BAc_import">Import backup</string>
   <string name="export_toast">Backed up %1$s to %2$s.</string>
   <string name="export_toast_no_tasks">No tasks to export.</string>
   <string name="import_summary_title">Restore summary</string>
@@ -316,7 +316,7 @@ File %1$s contained %2$s.\n\n
   <string name="quiet_hours">Quiet hours</string>
   <string name="attachment_directory">Attachment folder</string>
   <string name="backup_directory">Backup folder</string>
-  <string name="google_drive_backup">Copy to Google Drive</string>
+  <string name="google_drive_backup">Google Drive backup</string>
   <string name="miscellaneous">Miscellaneous</string>
   <string name="synchronization">Synchronization</string>
   <string name="subtasks">Subtasks</string>

app/src/main/res/xml/preferences_backups.xml

@@ -17,14 +17,14 @@
     android:title="@string/backup_directory"
     app:allowDividerAbove="true" />
 
-  <Preference
-    android:key="@string/backup_BAc_import"
-    android:title="@string/backup_BAc_import" />
-
   <Preference
     android:key="@string/backup_BAc_export"
     android:title="@string/backup_BAc_export" />
 
+  <Preference
+    android:key="@string/backup_BAc_import"
+    android:title="@string/backup_BAc_import" />
+
   <PreferenceCategory
     android:title="@string/automatic_backups">