Add custom order synchronization hack

Workaround for https://issuetracker.google.com/issues/132432317. When
enabled Tasks will synchronize parents and positions for all active
tasks.

app/src/main/java/com/todoroo/astrid/gtasks/api/GtasksInvoker.java

@@ -103,6 +103,19 @@ public class GtasksInvoker {
                 GtasksApiUtilities.unixTimeToGtasksCompletionTime(lastSyncDate).toStringRfc3339()));
   }
 
+  public com.google.api.services.tasks.model.Tasks getAllPositions(
+      String listId, @Nullable String pageToken) throws IOException {
+    return execute(
+        service
+            .tasks()
+            .list(listId)
+            .setMaxResults(100L)
+            .setShowDeleted(false)
+            .setShowHidden(true)
+            .setPageToken(pageToken)
+            .setFields("items(id,parent,position)"));
+  }
+
   public @Nullable Task createGtask(
       String listId, Task task, @Nullable String parent, @Nullable String previous)
       throws IOException {

app/src/main/java/org/tasks/data/GoogleTaskDao.java

@@ -116,6 +116,10 @@ public abstract class GoogleTaskDao {
       "UPDATE google_tasks SET gt_parent = IFNULL((SELECT gt_task FROM google_tasks AS p WHERE p.gt_remote_id = google_tasks.gt_remote_parent), gt_parent) WHERE gt_list_id = :listId AND gt_moved = 0 AND gt_remote_parent IS NOT NULL AND gt_remote_parent != ''")
   abstract void updateParents(String listId);
 
+  @Query(
+      "UPDATE google_tasks SET gt_remote_parent = :parent, gt_remote_order = :position WHERE gt_remote_id = :id")
+  public abstract void updatePosition(String id, String parent, String position);
+
   @Transaction
   public void reposition(String listId) {
     updateParents(listId);

app/src/main/java/org/tasks/gtasks/GoogleTaskSynchronizer.java

@@ -216,9 +216,36 @@ public class GoogleTaskSynchronizer {
       fetchAndApplyRemoteChanges(gtasksInvoker, list);
       googleTaskDao.reposition(list.getRemoteId());
     }
+    if (preferences.isPositionHackEnabled()) {
+      for (TaskList list : gtaskLists) {
+        List<com.google.api.services.tasks.model.Task> tasks = fetchPositions(gtasksInvoker, list.getId());
+        for (com.google.api.services.tasks.model.Task task : tasks) {
+          googleTaskDao.updatePosition(task.getId(), task.getParent(), task.getPosition());
+        }
+        googleTaskDao.reposition(list.getId());
+      }
+    }
     account.setEtag(eTag);
   }
 
+  private List<com.google.api.services.tasks.model.Task> fetchPositions(GtasksInvoker gtasksInvoker, String listId)
+      throws IOException {
+    List<com.google.api.services.tasks.model.Task> tasks = new ArrayList<>();
+    String nextPageToken = null;
+    do {
+      Tasks taskList = gtasksInvoker.getAllPositions(listId, nextPageToken);
+      if (taskList == null) {
+        break;
+      }
+      List<com.google.api.services.tasks.model.Task> items = taskList.getItems();
+      if (items != null) {
+        tasks.addAll(items);
+      }
+      nextPageToken = taskList.getNextPageToken();
+    } while (!Strings.isNullOrEmpty(nextPageToken));
+    return tasks;
+  }
+
   private void pushLocalChanges(GoogleTaskAccount account, GtasksInvoker gtasksInvoker)
       throws IOException {
     List<Task> tasks = taskDao.getGoogleTasksToPush(account.getAccount());

app/src/main/java/org/tasks/preferences/Preferences.java

@@ -5,6 +5,7 @@ import static com.google.common.collect.Iterables.filter;
 import static com.google.common.collect.Iterables.transform;
 import static com.google.common.collect.Sets.newHashSet;
 import static com.todoroo.andlib.utility.AndroidUtilities.atLeastKitKat;
+import static com.todoroo.andlib.utility.DateUtilities.now;
 import static java.util.Collections.emptySet;
 
 import android.content.ContentResolver;
@@ -511,4 +512,8 @@ public class Preferences {
   public boolean isFlipperEnabled() {
     return BuildConfig.DEBUG && getBoolean(R.string.p_flipper, false);
   }
+
+  public boolean isPositionHackEnabled() {
+    return getLong(R.string.p_google_tasks_position_hack, 0) > now() - TimeUnit.DAYS.toMillis(7);
+  }
 }

app/src/main/java/org/tasks/sync/SynchronizationPreferences.java

@@ -6,11 +6,13 @@
 
 package org.tasks.sync;
 
+import static com.todoroo.andlib.utility.DateUtilities.now;
 import static java.util.Arrays.asList;
 import static org.tasks.PermissionUtil.verifyPermissions;
 
 import android.content.Intent;
 import android.os.Bundle;
+import android.preference.CheckBoxPreference;
 import android.preference.Preference;
 import android.preference.PreferenceCategory;
 import androidx.annotation.NonNull;
@@ -98,6 +100,20 @@ public class SynchronizationPreferences extends InjectingPreferenceActivity {
             return false;
           });
     }
+
+    CheckBoxPreference positionHack =
+        (CheckBoxPreference) findPreference(R.string.google_tasks_position_hack);
+    positionHack.setChecked(preferences.isPositionHackEnabled());
+    positionHack.setOnPreferenceChangeListener(
+        (preference, newValue) -> {
+          if (newValue == null) {
+            return false;
+          }
+          preferences.setLong(
+              R.string.p_google_tasks_position_hack, ((Boolean) newValue) ? now() : 0);
+          return true;
+        });
+
     Preference addCaldavAccount = findPreference(R.string.p_add_caldav_account);
     if (inventory.hasPro()) {
       addCaldavAccount.setOnPreferenceClickListener(

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

@@ -311,4 +311,7 @@
   <string name="p_add_google_task_account">add_google_task_account</string>
   <string name="p_add_caldav_account">add_caldav_account</string>
   <string name="p_google_tasks_add_to_top">google_tasks_add_to_top</string>
+  <string name="p_google_tasks_position_hack">google_tasks_position_hack</string>
+  <string name="google_tasks_position_hack">Custom order synchronization fix</string>
+  <string name="google_tasks_position_hack_summary">Always perform a full synchronization to workaround https://issuetracker.google.com/issues/132432317. This setting will disable itself after seven days.</string>
 </resources>

app/src/main/res/xml/preferences_synchronization.xml

@@ -18,6 +18,11 @@
     android:key="@string/p_google_tasks_add_to_top"
     android:title="@string/google_tasks_add_to_top"/>
 
+  <CheckBoxPreference
+    android:key="@string/google_tasks_position_hack"
+    android:title="@string/google_tasks_position_hack"
+    android:summary="@string/google_tasks_position_hack_summary" />
+
   <PreferenceCategory
     android:key="@string/CalDAV"
     android:title="@string/CalDAV"/>