Merge branch 'master' into fastlanefastlane

# Conflicts:
#	fastlane/metadata/android/en-US/images/phoneScreenshots/1.png
#	fastlane/metadata/android/en-US/images/phoneScreenshots/2.png
#	fastlane/metadata/android/en-US/images/phoneScreenshots/4.png

13 files changed, 463 insertions, 110 deletions

diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AbstractSyncDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AbstractSyncDataProvider.java
index 166d6c519..11fb38a66 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AbstractSyncDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AbstractSyncDataProvider.java
@@ -1,9 +1,10 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import java.time.Instant;
 import java.util.ArrayList;
-import java.util.Date;
 import java.util.List;
 
+import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
 import it.niedermann.nextcloud.deck.model.interfaces.IRemoteEntity;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.ServerAdapter;
@@ -26,28 +27,37 @@ public abstract class AbstractSyncDataProvider<T extends IRemoteEntity> {
         }
     }
 
-    public void handleDeletes(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, List<T> entitiesFromServer){
+    public void handleDeletes(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, List<T> entitiesFromServer) {
         // do nothing as a default.
     }
 
     /**
      * Searches each entry of <code>listB</code> in list <code>listA</code> and returns the missing ones
+     *
      * @param listA List
      * @param listB List
      * @return all entries of <code>listB</code> missing in <code>listA</code>
      */
-    public static <T extends IRemoteEntity> List<T> findDelta(List<T> listA, List<T> listB){
+    public static <T extends IRemoteEntity> List<T> findDelta(List<T> listA, List<T> listB) {
         List<T> delta = new ArrayList<>();
         for (T b : listB) {
+            if (b == null) {
+                DeckLog.error("Entry in listB is null! skipping...");
+                continue;
+            }
             boolean found = false;
             for (T a : listA) {
-                if ((a.getLocalId()!= null && b.getLocalId()!= null ? (a.getLocalId().equals(b.getLocalId()))
+                if (a == null) {
+                    DeckLog.error("Entry in listA is null! skipping...");
+                    continue;
+                }
+                if ((a.getLocalId() != null && b.getLocalId() != null ? (a.getLocalId().equals(b.getLocalId()))
                         : a.getId().equals(b.getId())) && b.getAccountId() == a.getAccountId()) {
                     found = true;
                     break;
                 }
             }
-            if (!found){
+            if (!found) {
                 delta.add(b);
             }
         }
@@ -58,7 +68,14 @@ public abstract class AbstractSyncDataProvider<T extends IRemoteEntity> {
         children.add(child);
     }
 
-    public abstract void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<T>> responder, Date lastSync);
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<T>> responder, Instant lastSync) {
+        return;
+    }
+
+    public void getAllFromServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<List<T>> responder, Instant lastSync) {
+        // Overridden, because we also need the DB-Adapter at some points here (see ACL data provider)
+        getAllFromServer(serverAdapter, accountId, responder, lastSync);
+    }
 
     public abstract T getSingleFromDB(DataBaseAdapter dataBaseAdapter, long accountId, T entity);
 
@@ -72,7 +89,7 @@ public abstract class AbstractSyncDataProvider<T extends IRemoteEntity> {
 
     public abstract void deleteInDB(DataBaseAdapter dataBaseAdapter, long accountId, T t);
 
-    public void deletePhysicallyInDB(DataBaseAdapter dataBaseAdapter, long accountId, T t){
+    public void deletePhysicallyInDB(DataBaseAdapter dataBaseAdapter, long accountId, T t) {
         deleteInDB(dataBaseAdapter, accountId, t);
     }
 
@@ -106,7 +123,7 @@ public abstract class AbstractSyncDataProvider<T extends IRemoteEntity> {
         stillGoingDeeper = true;
     }
 
-    public abstract List<T> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync);
+    public abstract List<T> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync);
 
     public void goDeeperForUpSync(SyncHelper syncHelper, ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, IResponseCallback<Boolean> callback) {
         //do nothing
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AccessControlDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AccessControlDataProvider.java
index 3242ab7c1..6dde6b45c 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AccessControlDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AccessControlDataProvider.java
@@ -1,17 +1,24 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
-import java.util.Date;
+import java.time.Instant;
 import java.util.List;
+import java.util.concurrent.CountDownLatch;
 
+import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
 import it.niedermann.nextcloud.deck.model.AccessControl;
+import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.User;
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
+import it.niedermann.nextcloud.deck.model.ocs.user.GroupMemberUIDs;
+import it.niedermann.nextcloud.deck.model.ocs.user.OcsUser;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.ServerAdapter;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter;
+import it.niedermann.nextcloud.deck.persistence.sync.helpers.util.AsyncUtil;
 
 public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessControl> {
 
+    private static final Long TYPE_GROUP = 1L;
     private List<AccessControl> acl;
     private FullBoard board;
 
@@ -22,10 +29,66 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<AccessControl>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<List<AccessControl>> responder, Instant lastSync) {
+        AsyncUtil.awaitAsyncWork(acl.size(), latch -> {
+            for (AccessControl accessControl : acl) {
+                if (accessControl.getType() == TYPE_GROUP) {
+                    serverAdapter.searchGroupMembers(accessControl.getUser().getUid(), new IResponseCallback<GroupMemberUIDs>(responder.getAccount()) {
+                        @Override
+                        public void onResponse(GroupMemberUIDs response) {
+                            accessControl.setGroupMemberUIDs(response);
+                            if (response.getUids().size() > 0) {
+                                ensureGroupMembersInDB(getAccount(), dataBaseAdapter, serverAdapter, response);
+                            }
+                            latch.countDown();
+                        }
+
+                        @Override
+                        public void onError(Throwable throwable) {
+                            super.onError(throwable);
+                            latch.countDown();
+                        }
+                    });
+                } else latch.countDown();
+            }
+        });
+
         responder.onResponse(acl);
     }
 
+    private void ensureGroupMembersInDB(Account account, DataBaseAdapter dataBaseAdapter, ServerAdapter serverAdapter, GroupMemberUIDs response) {
+        CountDownLatch memberLatch = new CountDownLatch(response.getUids().size());
+        for (String uid : response.getUids()) {
+            User user = dataBaseAdapter.getUserByUidDirectly(account.getId(), uid);
+            if (user == null) {
+                // unknown user. fetch!
+                serverAdapter.getSingleUserData(uid, new IResponseCallback<OcsUser>(account) {
+                    @Override
+                    public void onResponse(OcsUser response) {
+                        DeckLog.log(response.toString());
+                        User user = new User();
+                        user.setUid(response.getId());
+                        user.setPrimaryKey(response.getId());
+                        user.setDisplayname(response.getDisplayName());
+                        dataBaseAdapter.createUser(account.getId(), user);
+                        memberLatch.countDown();
+                    }
+
+                    @Override
+                    public void onError(Throwable throwable) {
+                        super.onError(throwable);
+                        memberLatch.countDown();
+                    }
+                });
+            } else memberLatch.countDown();
+        }
+        try {
+            memberLatch.await();
+        } catch (InterruptedException e) {
+            DeckLog.logError(e);
+        }
+    }
+
     @Override
     public AccessControl getSingleFromDB(DataBaseAdapter dataBaseAdapter, long accountId, AccessControl entity) {
         return dataBaseAdapter.getAccessControlByRemoteIdDirectly(accountId, entity.getEntity().getId());
@@ -34,7 +97,26 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
     @Override
     public long createInDB(DataBaseAdapter dataBaseAdapter, long accountId, AccessControl entity) {
         prepareUser(dataBaseAdapter, accountId, entity);
-        return dataBaseAdapter.createAccessControl(accountId, entity);
+        long newId = dataBaseAdapter.createAccessControl(accountId, entity);
+        entity.setLocalId(newId);
+        handleGroupMemberships(dataBaseAdapter, entity);
+        return newId;
+    }
+
+    private void handleGroupMemberships(DataBaseAdapter dataBaseAdapter, AccessControl entity) {
+        if (entity.getType() != TYPE_GROUP) {
+            return;
+        }
+        dataBaseAdapter.deleteGroupMembershipsOfGroup(entity.getUser().getLocalId());
+        if (entity.getGroupMemberUIDs() == null) {
+            return;
+        }
+        for (String groupMemberUID : entity.getGroupMemberUIDs().getUids()) {
+            User member = dataBaseAdapter.getUserByUidDirectly(entity.getAccountId(), groupMemberUID);
+            if (member != null) {
+                dataBaseAdapter.addUserToGroup(entity.getUserId(), member.getLocalId());
+            }
+        }
     }
 
     private void prepareUser(DataBaseAdapter dataBaseAdapter, long accountId, AccessControl entity) {
@@ -42,6 +124,7 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
         if (user == null) {
             long userId = dataBaseAdapter.createUser(accountId, entity.getUser());
             entity.setUserId(userId);
+            entity.getUser().setLocalId(userId);
         } else {
             entity.setUserId(user.getLocalId());
             entity.getUser().setLocalId(user.getLocalId());
@@ -52,7 +135,9 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
     @Override
     public void updateInDB(DataBaseAdapter dataBaseAdapter, long accountId, AccessControl entity, boolean setStatus) {
         prepareUser(dataBaseAdapter, accountId, entity);
+        entity.setBoardId(board.getLocalId());
         dataBaseAdapter.updateAccessControl(entity, setStatus);
+        handleGroupMemberships(dataBaseAdapter, entity);
     }
 
     @Override
@@ -64,6 +149,9 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
     public void createOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<AccessControl> responder, AccessControl entity) {
         AccessControl acl = new AccessControl(entity);
         acl.setBoardId(board.getBoard().getId());
+        if (acl.getUser() == null && acl.getUserId() != null) {
+            acl.setUser(dataBaseAdapter.getUserByLocalIdDirectly(acl.getUserId()));
+        }
         serverAdapter.createAccessControl(board.getBoard().getId(), acl, responder);
     }
 
@@ -79,6 +167,7 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
 
     @Override
     public void deletePhysicallyInDB(DataBaseAdapter dataBaseAdapter, long accountId, AccessControl accessControl) {
+        dataBaseAdapter.deleteGroupMembershipsOfGroup(accessControl.getUser().getLocalId());
         dataBaseAdapter.deleteAccessControl(accessControl, false);
     }
 
@@ -88,7 +177,7 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
     }
 
     @Override
-    public List<AccessControl> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<AccessControl> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         return dataBaseAdapter.getLocallyChangedAccessControl(accountId, board.getLocalId());
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/ActivityDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/ActivityDataProvider.java
index a3785ca78..5a7abf732 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/ActivityDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/ActivityDataProvider.java
@@ -1,7 +1,9 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
-import java.util.ArrayList;
-import java.util.Date;
+import androidx.annotation.NonNull;
+
+import java.time.Instant;
+import java.util.Collections;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
@@ -12,15 +14,16 @@ import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter
 
 public class ActivityDataProvider extends AbstractSyncDataProvider<Activity> {
 
-    protected Card card;
+    @NonNull
+    private final Card card;
 
-    public ActivityDataProvider(AbstractSyncDataProvider<?> parent, Card card) {
+    public ActivityDataProvider(AbstractSyncDataProvider<?> parent, @NonNull Card card) {
         super(parent);
         this.card = card;
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<Activity>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<Activity>> responder, Instant lastSync) {
         serverAdapter.getActivitiesForCard(card.getId(), responder);
     }
 
@@ -65,7 +68,7 @@ public class ActivityDataProvider extends AbstractSyncDataProvider<Activity> {
     }
 
     @Override
-    public List<Activity> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
-        return new ArrayList<>();
+    public List<Activity> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
+        return Collections.emptyList();
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AttachmentDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AttachmentDataProvider.java
index 37e00dada..781f7b1f4 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AttachmentDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AttachmentDataProvider.java
@@ -4,7 +4,7 @@ import android.net.Uri;
 
 import java.io.File;
 import java.io.IOException;
-import java.util.Date;
+import java.time.Instant;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.DeckLog;
@@ -32,7 +32,7 @@ public class AttachmentDataProvider extends AbstractSyncDataProvider<Attachment>
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<Attachment>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<Attachment>> responder, Instant lastSync) {
         responder.onResponse(attachments);
     }
 
@@ -104,7 +104,7 @@ public class AttachmentDataProvider extends AbstractSyncDataProvider<Attachment>
     }
 
     @Override
-    public List<Attachment> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<Attachment> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         return dataBaseAdapter.getLocallyChangedAttachmentsByLocalCardIdDirectly(accountId, card.getLocalId());
     }
 
@@ -120,7 +120,7 @@ public class AttachmentDataProvider extends AbstractSyncDataProvider<Attachment>
             dataBaseAdapter.deleteAttachment(accountId, attachment, false);
         }
         for (Attachment attachment : entitiesFromServer) {
-            if (attachment.getDeletedAt() != null && attachment.getDeletedAt().getTime() != 0) {
+            if (attachment.getDeletedAt() != null && attachment.getDeletedAt().toEpochMilli() != 0) {
                 Attachment toDelete = dataBaseAdapter.getAttachmentByRemoteIdDirectly(accountId, attachment.getId());
                 if (toDelete != null) {
                     dataBaseAdapter.deleteAttachment(accountId, toDelete, false);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/BoardDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/BoardDataProvider.java
index 98163029f..f5e071adb 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/BoardDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/BoardDataProvider.java
@@ -1,14 +1,16 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import android.annotation.SuppressLint;
+
+import com.nextcloud.android.sso.api.ParsedResponse;
+
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Date;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
-import java.util.concurrent.CountDownLatch;
 
-import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
 import it.niedermann.nextcloud.deck.model.AccessControl;
 import it.niedermann.nextcloud.deck.model.Board;
@@ -19,16 +21,33 @@ import it.niedermann.nextcloud.deck.model.full.FullStack;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.ServerAdapter;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter;
 import it.niedermann.nextcloud.deck.persistence.sync.helpers.SyncHelper;
+import it.niedermann.nextcloud.deck.persistence.sync.helpers.util.AsyncUtil;
 
 public class BoardDataProvider extends AbstractSyncDataProvider<FullBoard> {
 
-    public BoardDataProvider(){
+    public BoardDataProvider() {
         super(null);
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<FullBoard>> responder, Date lastSync) {
-        serverAdapter.getBoards(responder);
+    public void getAllFromServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<List<FullBoard>> responder, Instant lastSync) {
+        serverAdapter.getBoards(new IResponseCallback<ParsedResponse<List<FullBoard>>>(responder.getAccount()) {
+            @Override
+            public void onResponse(ParsedResponse<List<FullBoard>> response) {
+                String etag = response.getHeaders().get("ETag");
+                if (etag != null && !etag.equals(account.getBoardsEtag())) {
+                    account.setBoardsEtag(etag);
+                    dataBaseAdapter.updateAccount(account);
+                }
+                responder.onResponse(response.getResponse());
+            }
+
+            @SuppressLint("MissingSuperCall")
+            @Override
+            public void onError(Throwable throwable) {
+                responder.onError(throwable);
+            }
+        });
     }
 
     @Override
@@ -39,27 +58,65 @@ public class BoardDataProvider extends AbstractSyncDataProvider<FullBoard> {
     @Override
     public long createInDB(DataBaseAdapter dataBaseAdapter, long accountId, FullBoard entity) {
         handleOwner(dataBaseAdapter, accountId, entity);
-        return dataBaseAdapter.createBoardDirectly(accountId, entity.getBoard());
+        Long localId = dataBaseAdapter.createBoardDirectly(accountId, entity.getBoard());
+        entity.getBoard().setLocalId(localId);
+        handleUsers(dataBaseAdapter, accountId, entity);
+        return localId;
     }
 
     private void handleOwner(DataBaseAdapter dataBaseAdapter, long accountId, FullBoard entity) {
-        if (entity.getOwner()!=null) {
-            User remoteOwner = entity.getOwner();
-            User owner = dataBaseAdapter.getUserByUidDirectly(accountId, remoteOwner.getUid());
-            if (owner == null){
-                dataBaseAdapter.createUser(accountId, remoteOwner);
-            } else {
-                dataBaseAdapter.updateUser(accountId, remoteOwner, false);
-            }
-            owner = dataBaseAdapter.getUserByUidDirectly(accountId, remoteOwner.getUid());
+        if (entity.getOwner() != null) {
+            User owner = createOrUpdateUser(dataBaseAdapter, accountId, entity.getOwner());
             entity.getBoard().setOwnerId(owner.getLocalId());
         }
     }
 
+    private void handleUsers(DataBaseAdapter dataBaseAdapter, long accountId, FullBoard entity) {
+        dataBaseAdapter.deleteBoardMembershipsOfBoard(entity.getLocalId());
+        if (entity.getUsers() != null && !entity.getUsers().isEmpty()) {
+            for (User user : entity.getUsers()) {
+                if (user == null) {
+                    continue;
+                }
+                User existing = createOrUpdateUser(dataBaseAdapter, accountId, user);
+                dataBaseAdapter.addUserToBoard(existing.getLocalId(), entity.getLocalId());
+            }
+        }
+    }
+
+    private User createOrUpdateUser(DataBaseAdapter dataBaseAdapter, long accountId, User remoteUser) {
+        User owner = dataBaseAdapter.getUserByUidDirectly(accountId, remoteUser.getUid());
+        if (owner == null) {
+            dataBaseAdapter.createUser(accountId, remoteUser);
+        } else {
+            dataBaseAdapter.updateUser(accountId, remoteUser, false);
+        }
+        return dataBaseAdapter.getUserByUidDirectly(accountId, remoteUser.getUid());
+    }
+
     @Override
     public void updateInDB(DataBaseAdapter dataBaseAdapter, long accountId, FullBoard entity, boolean setStatus) {
+        handleDefaultLabels(dataBaseAdapter, entity);
         handleOwner(dataBaseAdapter, accountId, entity);
         dataBaseAdapter.updateBoard(entity.getBoard(), setStatus);
+        handleUsers(dataBaseAdapter, accountId, entity);
+    }
+
+    private void handleDefaultLabels(DataBaseAdapter dataBaseAdapter, FullBoard entity) {
+        // ## merge labels (created at board creation):
+        // the server creates four default labels. if a board is copied, they will also be copied. At sync, after creating the board, the labels are already there.
+        // this merges the created default ones with the ones i already have.
+        if (entity != null && entity.getLabels() != null) {
+            for (Label label : entity.getLabels()) {
+                // does this label exist and unknown to server yet?
+                Label existing = dataBaseAdapter.getLabelByBoardIdAndTitleDirectly(entity.getLocalId(), label.getTitle());
+                if (existing != null && existing.getId() == null) {
+                    // take our label and lets say it IS the same as on server (but use the local color, no matter what the server says)
+                    existing.setId(label.getId());
+                    dataBaseAdapter.updateLabel(existing, false);
+                }
+            }
+        }
     }
 
     @Override
@@ -71,19 +128,19 @@ public class BoardDataProvider extends AbstractSyncDataProvider<FullBoard> {
     @Override
     public void goDeeper(SyncHelper syncHelper, FullBoard existingEntity, FullBoard entityFromServer, IResponseCallback<Boolean> callback) {
         List<Label> labels = entityFromServer.getLabels();
-        if (labels != null && !labels.isEmpty()){
+        if (labels != null && !labels.isEmpty()) {
             syncHelper.doSyncFor(new LabelDataProvider(this, existingEntity.getBoard(), labels));
         }
 
         List<AccessControl> acl = entityFromServer.getParticipants();
-        if (acl != null && !acl.isEmpty()){
-            for (AccessControl ac : acl){
+        if (acl != null && !acl.isEmpty()) {
+            for (AccessControl ac : acl) {
                 ac.setBoardId(existingEntity.getLocalId());
             }
             syncHelper.doSyncFor(new AccessControlDataProvider(this, existingEntity, acl));
         }
 
-        if (entityFromServer.getStacks() != null && !entityFromServer.getStacks().isEmpty()){
+        if (entityFromServer.getStacks() != null && !entityFromServer.getStacks().isEmpty()) {
             syncHelper.doSyncFor(new StackDataProvider(this, existingEntity));
         }
     }
@@ -94,7 +151,7 @@ public class BoardDataProvider extends AbstractSyncDataProvider<FullBoard> {
     }
 
     @Override
-    public List<FullBoard> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<FullBoard> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         return dataBaseAdapter.getLocallyChangedBoards(accountId);
     }
 
@@ -102,21 +159,17 @@ public class BoardDataProvider extends AbstractSyncDataProvider<FullBoard> {
     public void goDeeperForUpSync(SyncHelper syncHelper, ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, IResponseCallback<Boolean> callback) {
         Long accountId = callback.getAccount().getId();
         List<Label> locallyChangedLabels = dataBaseAdapter.getLocallyChangedLabels(accountId);
-        CountDownLatch countDownLatch = new CountDownLatch(locallyChangedLabels.size());
-        for (Label label : locallyChangedLabels) {
-            Board board = dataBaseAdapter.getBoardByLocalIdDirectly(label.getBoardId());
-            label.setBoardId(board.getId());
-            syncHelper.doUpSyncFor(new LabelDataProvider(this, board, Collections.singletonList(label)), countDownLatch);
-        }
-        try {
-            countDownLatch.await();
-        } catch (InterruptedException e) {
-            DeckLog.logError(e);
-        }
+        AsyncUtil.awaitAsyncWork(locallyChangedLabels.size(), (countDownLatch) -> {
+            for (Label label : locallyChangedLabels) {
+                Board board = dataBaseAdapter.getBoardByLocalIdDirectly(label.getBoardId());
+                label.setBoardId(board.getId());
+                syncHelper.doUpSyncFor(new LabelDataProvider(this, board, Collections.singletonList(label)), countDownLatch);
+            }
+        });
 
         List<Long> localBoardIDsWithChangedACL = dataBaseAdapter.getBoardIDsOfLocallyChangedAccessControl(accountId);
         for (Long boardId : localBoardIDsWithChangedACL) {
-            syncHelper.doUpSyncFor(new AccessControlDataProvider(this, dataBaseAdapter.getFullBoardByLocalIdDirectly(accountId, boardId) ,new ArrayList<>()));
+            syncHelper.doUpSyncFor(new AccessControlDataProvider(this, dataBaseAdapter.getFullBoardByLocalIdDirectly(accountId, boardId), new ArrayList<>()));
         }
 
         Set<Long> syncedBoards = new HashSet<>();
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardDataProvider.java
index 03e02bd70..0ceac2cd8 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardDataProvider.java
@@ -1,12 +1,15 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import android.annotation.SuppressLint;
+
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Date;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.exceptions.DeckException;
 import it.niedermann.nextcloud.deck.exceptions.OfflineException;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.Attachment;
@@ -37,7 +40,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<FullCard>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<FullCard>> responder, Instant lastSync) {
 
         List<FullCard> result = new ArrayList<>();
         if (stack.getCards() == null || stack.getCards().isEmpty()) {
@@ -54,6 +57,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
                     }
                 }
 
+                @SuppressLint("MissingSuperCall")
                 @Override
                 public void onError(Throwable throwable) {
                     responder.onError(throwable);
@@ -70,7 +74,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
     @Override
     public long createInDB(DataBaseAdapter dataBaseAdapter, long accountId, FullCard entity) {
         fixRelations(dataBaseAdapter, accountId, entity);
-        return dataBaseAdapter.createCard(accountId, entity.getCard());
+        return dataBaseAdapter.createCardDirectly(accountId, entity.getCard());
     }
 
     protected CardUpdate toCardUpdate(FullCard card) {
@@ -144,10 +148,17 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
         } else {
             DeckLog.verbose("Comments - Version is too low, DONT SYNC");
         }
+        syncHelper.doSyncFor(new OcsProjectDataProvider(this, existingEntity.getCard()));
     }
 
     @Override
     public void createOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<FullCard> responder, FullCard entity) {
+        if (stack.getId() == null) {
+            responder.onError(new DeckException(DeckException.Hint.DEPENDENCY_NOT_SYNCED_YET, "Stack \"" +
+                    stack.getStack().getTitle() + "\" for Card \"" + entity.getCard().getTitle() +
+                    "\" is not synced yet. Perform a full sync (pull to refresh) as soon as you are online again."));
+            return;
+        }
         entity.getCard().setStackId(stack.getId());
         serverAdapter.createCard(board.getId(), stack.getId(), entity.getCard(), responder);
     }
@@ -170,7 +181,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
     }
 
     @Override
-    public List<FullCard> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<FullCard> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         if (board == null || stack == null) {
             // no cards changed!
             // (see call from StackDataProvider: goDeeperForUpSync called with null for board.)
@@ -184,8 +195,13 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
     public void goDeeperForUpSync(SyncHelper syncHelper, ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, IResponseCallback<Boolean> callback) {
         FullStack stack;
         Board board;
+        List<JoinCardWithLabel> changedLabels;
+        if (this.stack == null) {
+            changedLabels = dataBaseAdapter.getAllChangedLabelJoins();
+        } else {
+            changedLabels = dataBaseAdapter.getAllChangedLabelJoinsForStack(this.stack.getLocalId());
+        }
 
-        List<JoinCardWithLabel> changedLabels = dataBaseAdapter.getAllChangedJoins();
         Account account = callback.getAccount();
         for (JoinCardWithLabel changedLabelLocal : changedLabels) {
             Card card = dataBaseAdapter.getCardByLocalIdDirectly(account.getId(), changedLabelLocal.getCardId());
@@ -201,7 +217,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
                 board = this.board;
             }
 
-            JoinCardWithLabel changedLabel = dataBaseAdapter.getRemoteIdsForJoin(changedLabelLocal.getCardId(), changedLabelLocal.getLabelId());
+            JoinCardWithLabel changedLabel = dataBaseAdapter.getAllChangedLabelJoinsWithRemoteIDs(changedLabelLocal.getCardId(), changedLabelLocal.getLabelId());
             if (changedLabel.getStatusEnum() == DBStatus.LOCAL_DELETED) {
                 if (changedLabel.getLabelId() == null || changedLabel.getCardId() == null) {
                     dataBaseAdapter.deleteJoinedLabelForCardPhysicallyByRemoteIDs(account.getId(), changedLabel.getCardId(), changedLabel.getLabelId());
@@ -229,11 +245,22 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
 
             }
         }
-        List<JoinCardWithUser> deletedUsers = dataBaseAdapter.getAllDeletedUserJoinsWithRemoteIDs();
-        for (JoinCardWithUser deletedUser : deletedUsers) {
-            Card card = dataBaseAdapter.getCardByRemoteIdDirectly(account.getId(), deletedUser.getCardId());
+
+        List<JoinCardWithUser> changedUsers;
+        if (this.stack == null) {
+            changedUsers = dataBaseAdapter.getAllChangedUserJoinsWithRemoteIDs();
+        } else {
+            changedUsers = dataBaseAdapter.getAllChangedUserJoinsWithRemoteIDsForStack(this.stack.getLocalId());
+        }
+        for (JoinCardWithUser changedUser : changedUsers) {
+            // not already known to server?
+            if (changedUser.getCardId() == null) {
+                //skip for now
+                continue;
+            }
+            Card card = dataBaseAdapter.getCardByRemoteIdDirectly(account.getId(), changedUser.getCardId());
             if (this.stack == null) {
-                stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getLocalId());
+                stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getStackId());
             } else {
                 stack = this.stack;
             }
@@ -243,16 +270,16 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
             } else {
                 board = this.board;
             }
-            User user = dataBaseAdapter.getUserByLocalIdDirectly(deletedUser.getUserId());
-            if (deletedUser.getStatusEnum() == DBStatus.LOCAL_DELETED) {
-                serverAdapter.unassignUserFromCard(board.getId(), stack.getId(), deletedUser.getCardId(), user.getUid(), new IResponseCallback<Void>(account) {
+            User user = dataBaseAdapter.getUserByLocalIdDirectly(changedUser.getUserId());
+            if (changedUser.getStatusEnum() == DBStatus.LOCAL_DELETED) {
+                serverAdapter.unassignUserFromCard(board.getId(), stack.getId(), changedUser.getCardId(), user.getUid(), new IResponseCallback<Void>(account) {
                     @Override
                     public void onResponse(Void response) {
-                        dataBaseAdapter.deleteJoinedUserForCardPhysicallyByRemoteIDs(account.getId(), deletedUser.getCardId(), user.getUid());
+                        dataBaseAdapter.deleteJoinedUserForCardPhysicallyByRemoteIDs(account.getId(), changedUser.getCardId(), user.getUid());
                     }
                 });
-            } else if (deletedUser.getStatusEnum() == DBStatus.LOCAL_EDITED) {
-                serverAdapter.assignUserToCard(board.getId(), stack.getId(), deletedUser.getCardId(), user.getUid(), new IResponseCallback<Void>(account) {
+            } else if (changedUser.getStatusEnum() == DBStatus.LOCAL_EDITED) {
+                serverAdapter.assignUserToCard(board.getId(), stack.getId(), changedUser.getCardId(), user.getUid(), new IResponseCallback<Void>(account) {
                     @Override
                     public void onResponse(Void response) {
                         dataBaseAdapter.setStatusForJoinCardWithUser(card.getLocalId(), user.getLocalId(), DBStatus.UP_TO_DATE.getId());
@@ -261,7 +288,12 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
             }
         }
 
-        List<Attachment> attachments = dataBaseAdapter.getLocallyChangedAttachmentsDirectly(account.getId());
+        List<Attachment> attachments;
+        if (this.stack == null) {
+            attachments = dataBaseAdapter.getLocallyChangedAttachmentsDirectly(account.getId());
+        } else {
+            attachments = dataBaseAdapter.getLocallyChangedAttachmentsForStackDirectly(this.stack.getLocalId());
+        }
         for (Attachment attachment : attachments) {
             FullCard card = dataBaseAdapter.getFullCardByLocalIdDirectly(account.getId(), attachment.getCardId());
             stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getCard().getStackId());
@@ -269,7 +301,12 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
             syncHelper.doUpSyncFor(new AttachmentDataProvider(this, board, stack.getStack(), card, Collections.singletonList(attachment)));
         }
 
-        List<Card> cardsWithChangedComments = dataBaseAdapter.getCardsWithLocallyChangedCommentsDirectly(account.getId());
+        List<Card> cardsWithChangedComments;
+        if (this.stack == null) {
+            cardsWithChangedComments = dataBaseAdapter.getCardsWithLocallyChangedCommentsDirectly(account.getId());
+        } else {
+            cardsWithChangedComments = dataBaseAdapter.getCardsWithLocallyChangedCommentsForStackDirectly(this.stack.getLocalId());
+        }
         for (Card card : cardsWithChangedComments) {
             syncHelper.doUpSyncFor(new DeckCommentsDataProvider(this, card));
         }
@@ -279,7 +316,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
 
     @Override
     public void handleDeletes(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, List<FullCard> entitiesFromServer) {
-        List<FullCard> localCards = dataBaseAdapter.getFullCardsForStackDirectly(accountId, stack.getLocalId());
+        List<FullCard> localCards = dataBaseAdapter.getFullCardsForStackDirectly(accountId, stack.getLocalId(), null);
         List<FullCard> delta = findDelta(entitiesFromServer, localCards);
         for (FullCard cardToDelete : delta) {
             if (cardToDelete.getId() == null) {
@@ -294,6 +331,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
                         // do not delete, it's still there and was just moved!
                     }
 
+                    @SuppressLint("MissingSuperCall")
                     @Override
                     public void onError(Throwable throwable) {
                         if (!(throwable instanceof OfflineException)) {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/DeckCommentsDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/DeckCommentsDataProvider.java
index 5b9be120f..06ef3030d 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/DeckCommentsDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/DeckCommentsDataProvider.java
@@ -1,8 +1,8 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Date;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.DeckLog;
@@ -24,10 +24,13 @@ public class DeckCommentsDataProvider extends AbstractSyncDataProvider<OcsCommen
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<OcsComment>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<OcsComment>> responder, Instant lastSync) {
         serverAdapter.getCommentsForRemoteCardId(card.getId(), new IResponseCallback<OcsComment>(responder.getAccount()) {
             @Override
             public void onResponse(OcsComment response) {
+                if (response == null) {
+                    response = new OcsComment();
+                }
                 List<OcsComment> comments = response.split();
                 Collections.sort(comments, (o1, o2) -> o1.getSingle().getCreationDateTime().compareTo(o2.getSingle().getCreationDateTime()));
                 verifyCommentListIntegrity(comments);
@@ -131,7 +134,7 @@ public class DeckCommentsDataProvider extends AbstractSyncDataProvider<OcsCommen
     }
 
     @Override
-    public List<OcsComment> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<OcsComment> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         return new OcsComment(dataBaseAdapter.getLocallyChangedCommentsByLocalCardIdDirectly(accountId, card.getLocalId())).split();
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/LabelDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/LabelDataProvider.java
index 403d71f87..caa7c68e6 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/LabelDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/LabelDataProvider.java
@@ -1,8 +1,9 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
-import java.util.Date;
+import java.time.Instant;
 import java.util.List;
 
+import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
 import it.niedermann.nextcloud.deck.exceptions.HandledServerErrors;
 import it.niedermann.nextcloud.deck.model.Board;
@@ -12,14 +13,14 @@ import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter
 
 public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
 
-    private List<Label> labels;
-    private Board board;
+    private final List<Label> labels;
+    private final Board board;
 
     public LabelDataProvider(AbstractSyncDataProvider<?> parent, Board board, List<Label> labels) {
         super(parent);
         this.board = board;
         this.labels = labels;
-        if (this.labels!= null && board != null){
+        if (this.labels != null && board != null) {
             for (Label label : labels) {
                 label.setBoardId(board.getLocalId());
             }
@@ -27,7 +28,7 @@ public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<Label>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<Label>> responder, Instant lastSync) {
         responder.onResponse(labels);
     }
 
@@ -44,7 +45,7 @@ public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
             updateInDB(dataBaseAdapter, accountId, entity, false);
             return entity.getLocalId();
         } else {
-            return dataBaseAdapter.createLabel(accountId, entity);
+            return dataBaseAdapter.createLabelDirectly(accountId, entity);
         }
     }
 
@@ -53,7 +54,7 @@ public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
         dataBaseAdapter.updateLabel(entity, setStatus);
     }
 
-    private IResponseCallback<Label> getLabelUniqueHandler(DataBaseAdapter dataBaseAdapter, Label entitiy, IResponseCallback<Label> responder){
+    private IResponseCallback<Label> getLabelUniqueHandler(DataBaseAdapter dataBaseAdapter, Label entitiy, IResponseCallback<Label> responder) {
         return new IResponseCallback<Label>(responder.getAccount()) {
             @Override
             public void onResponse(Label response) {
@@ -62,10 +63,13 @@ public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
 
             @Override
             public void onError(Throwable throwable) {
-                if (HandledServerErrors.LABELS_TITLE_MUST_BE_UNIQUE == HandledServerErrors.fromThrowable(throwable)){
+                if (HandledServerErrors.LABELS_TITLE_MUST_BE_UNIQUE == HandledServerErrors.fromThrowable(throwable)) {
+                    DeckLog.log(throwable.getCause().getMessage() + ": " + entitiy.toString());
                     dataBaseAdapter.deleteLabelPhysically(entitiy);
+                    responder.onResponse(entitiy);
+                } else {
+                    responder.onError(throwable);
                 }
-                responder.onError(throwable);
             }
         };
     }
@@ -92,7 +96,7 @@ public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
     }
 
     @Override
-    public List<Label> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<Label> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         return labels;
     }
 
@@ -105,7 +109,7 @@ public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
     public void handleDeletes(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, List<Label> entitiesFromServer) {
         List<Label> deletedLabels = findDelta(labels, dataBaseAdapter.getFullBoardByLocalIdDirectly(accountId, board.getLocalId()).getLabels());
         for (Label deletedLabel : deletedLabels) {
-            if (deletedLabel.getId()!=null){
+            if (deletedLabel.getId() != null) {
                 // preserve new, unsynced card.
                 dataBaseAdapter.deleteLabelPhysically(deletedLabel);
             }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/OcsProjectDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/OcsProjectDataProvider.java
new file mode 100644
index 000000000..b9bfb8b31
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/OcsProjectDataProvider.java
@@ -0,0 +1,100 @@
+package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
+
+import java.time.Instant;
+import java.util.Collections;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.model.Card;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProject;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectList;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectResource;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.ServerAdapter;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter;
+
+public class OcsProjectDataProvider extends AbstractSyncDataProvider<OcsProject> {
+    private Card card;
+
+    public OcsProjectDataProvider(AbstractSyncDataProvider<?> parent, Card card) {
+        super(parent);
+        this.card = card;
+    }
+
+    @Override
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<OcsProject>> responder, Instant lastSync) {
+        serverAdapter.getProjectsForCard(card.getId(), new IResponseCallback<OcsProjectList>(responder.getAccount()) {
+            @Override
+            public void onResponse(OcsProjectList response) {
+                responder.onResponse(response.getProjects());
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                super.onError(throwable);
+                // dont break the sync!
+                DeckLog.logError(throwable);
+                responder.onResponse(Collections.emptyList());
+            }
+        });
+    }
+
+    @Override
+    public OcsProject getSingleFromDB(DataBaseAdapter dataBaseAdapter, long accountId, OcsProject entity) {
+        return dataBaseAdapter.getProjectByRemoteIdDirectly(accountId, entity.getId());
+    }
+
+    @Override
+    public long createInDB(DataBaseAdapter dataBaseAdapter, long accountId, OcsProject entity) {
+        Long newId = dataBaseAdapter.createProjectDirectly(accountId, entity);
+        entity.setLocalId(newId);
+        updateResources(dataBaseAdapter, accountId, entity);
+        return newId;
+    }
+
+    @Override
+    public void updateInDB(DataBaseAdapter dataBaseAdapter, long accountId, OcsProject entity, boolean setStatus) {
+        dataBaseAdapter.updateProjectDirectly(accountId, entity);
+        dataBaseAdapter.deleteProjectResourcesForProjectIdDirectly(entity.getLocalId());
+        updateResources(dataBaseAdapter, accountId, entity);
+    }
+
+    @Override
+    public void deleteInDB(DataBaseAdapter dataBaseAdapter, long accountId, OcsProject ocsProject) {
+        if (ocsProject != null && ocsProject.getLocalId() != null) {
+            dataBaseAdapter.deleteProjectDirectly(ocsProject);
+        }
+    }
+
+    private void updateResources(DataBaseAdapter dataBaseAdapter, Long accountId, OcsProject entity) {
+        if (entity.getResources() != null) {
+            for (OcsProjectResource resource : entity.getResources()) {
+                resource.setProjectId(entity.getLocalId());
+                resource.setLocalId(dataBaseAdapter.createProjectResourceDirectly(accountId, resource));
+                if ("deck-card".equals(resource.getType())) {
+                    dataBaseAdapter.assignCardToProjectIfMissng(accountId, entity.getLocalId(), resource.getId());
+                }
+            }
+        }
+    }
+
+    @Override
+    public void createOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<OcsProject> responder, OcsProject entity) {
+        // Do Nothing
+    }
+
+    @Override
+    public void updateOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<OcsProject> callback, OcsProject entity) {
+        // Do Nothing
+    }
+
+    @Override
+    public void deleteOnServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<Void> callback, OcsProject entity, DataBaseAdapter dataBaseAdapter) {
+        // Do Nothing
+    }
+
+    @Override
+    public List<OcsProject> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
+        return Collections.emptyList();
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/StackDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/StackDataProvider.java
index a3c123afd..93761d616 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/StackDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/StackDataProvider.java
@@ -1,12 +1,13 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import java.time.Instant;
 import java.util.Collections;
-import java.util.Date;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.ConcurrentSkipListSet;
 
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.exceptions.DeckException;
 import it.niedermann.nextcloud.deck.model.Board;
 import it.niedermann.nextcloud.deck.model.Card;
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
@@ -19,13 +20,15 @@ import it.niedermann.nextcloud.deck.persistence.sync.helpers.SyncHelper;
 public class StackDataProvider extends AbstractSyncDataProvider<FullStack> {
     private FullBoard board;
 
+    private Set<Long> syncedStacks = new ConcurrentSkipListSet<>();
+
     public StackDataProvider(AbstractSyncDataProvider<?> parent, FullBoard board) {
         super(parent);
         this.board = board;
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<FullStack>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<FullStack>> responder, Instant lastSync) {
         serverAdapter.getStacks(board.getId(), responder);
     }
 
@@ -54,12 +57,12 @@ public class StackDataProvider extends AbstractSyncDataProvider<FullStack> {
 
     @Override
     public void goDeeper(SyncHelper syncHelper, FullStack existingEntity, FullStack entityFromServer, IResponseCallback<Boolean> callback) {
-       boolean serverHasCards = entityFromServer.getCards() != null && !entityFromServer.getCards().isEmpty();
-       boolean weHaveCards = existingEntity.getCards() != null && !existingEntity.getCards().isEmpty();
-        if (serverHasCards || weHaveCards){
+        boolean serverHasCards = entityFromServer.getCards() != null && !entityFromServer.getCards().isEmpty();
+        boolean weHaveCards = existingEntity.getCards() != null && !existingEntity.getCards().isEmpty();
+        if (serverHasCards || weHaveCards) {
             existingEntity.setCards(entityFromServer.getCards());
             List<Card> cards = existingEntity.getCards();
-            if (cards != null ){
+            if (cards != null) {
                 for (Card card : cards) {
                     card.setStackId(existingEntity.getLocalId());
                 }
@@ -72,6 +75,9 @@ public class StackDataProvider extends AbstractSyncDataProvider<FullStack> {
 
     @Override
     public void createOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<FullStack> responder, FullStack entity) {
+        if (board.getId() == null) {
+            throw new DeckException(DeckException.Hint.DEPENDENCY_NOT_SYNCED_YET, "Board for this stack is not synced yet. Perform a full sync (pull to referesh) as soon as you are online again.");
+        }
         entity.getStack().setBoardId(board.getId());
         serverAdapter.createStack(board.getBoard(), entity.getStack(), responder);
     }
@@ -89,8 +95,8 @@ public class StackDataProvider extends AbstractSyncDataProvider<FullStack> {
     }
 
     @Override
-    public List<FullStack> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
-        if (board == null){
+    public List<FullStack> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
+        if (board == null) {
             // no stacks changed!
             // (see call from BoardDataProvider: goDeeperForUpSync called with null for board.)
             // so we can just skip this one and proceed with cards.
@@ -103,16 +109,19 @@ public class StackDataProvider extends AbstractSyncDataProvider<FullStack> {
     @Override
     public void goDeeperForUpSync(SyncHelper syncHelper, ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, IResponseCallback<Boolean> callback) {
         List<FullCard> changedCards = dataBaseAdapter.getLocallyChangedCardsDirectly(callback.getAccount().getId());
-        Set<Long> syncedStacks = new HashSet<>();
-        if (changedCards != null && changedCards.size() > 0){
+        if (changedCards != null && !changedCards.isEmpty()) {
             for (FullCard changedCard : changedCards) {
                 long stackId = changedCard.getCard().getStackId();
-                boolean added = syncedStacks.add(stackId);
-                if (added) {
+                boolean alreadySynced = syncedStacks.contains(stackId);
+                if (!alreadySynced) {
                     FullStack stack = dataBaseAdapter.getFullStackByLocalIdDirectly(stackId);
-                    Board board = dataBaseAdapter.getBoardByLocalIdDirectly(stack.getStack().getBoardId());
-                    changedCard.getCard().setStackId(stack.getId());
-                    syncHelper.doUpSyncFor(new CardDataProvider(this, board, stack));
+                    // already synced and known to server?
+                    if (stack.getStack().getId() != null) {
+                        syncedStacks.add(stackId);
+                        Board board = dataBaseAdapter.getBoardByLocalIdDirectly(stack.getStack().getBoardId());
+                        changedCard.getCard().setStackId(stack.getId());
+                        syncHelper.doUpSyncFor(new CardDataProvider(this, board, stack));
+                    }
                 }
             }
         } else {
@@ -132,7 +141,7 @@ public class StackDataProvider extends AbstractSyncDataProvider<FullStack> {
         List<FullStack> localStacks = dataBaseAdapter.getFullStacksForBoardDirectly(accountId, board.getLocalId());
         List<FullStack> delta = findDelta(entitiesFromServer, localStacks);
         for (FullStack stackToDelete : delta) {
-            if (stackToDelete.getId() == null){
+            if (stackToDelete.getId() == null) {
                 // not pushed up yet so:
                 continue;
             }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/UserDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/UserDataProvider.java
index 60c906bda..279ce9e55 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/UserDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/UserDataProvider.java
@@ -1,6 +1,6 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
-import java.util.Date;
+import java.time.Instant;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
@@ -27,7 +27,7 @@ public class UserDataProvider extends AbstractSyncDataProvider<User> {
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<User>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<User>> responder, Instant lastSync) {
         responder.onResponse(users);
     }
 
@@ -67,7 +67,7 @@ public class UserDataProvider extends AbstractSyncDataProvider<User> {
     }
 
     @Override
-    public List<User> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<User> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         return null;
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWitAclDownSyncDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWithAclDownSyncDataProvider.java
index 326d257ab..8516f0fc0 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWitAclDownSyncDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWithAclDownSyncDataProvider.java
@@ -11,7 +11,7 @@ import it.niedermann.nextcloud.deck.persistence.sync.helpers.SyncHelper;
 import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.AccessControlDataProvider;
 import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.BoardDataProvider;
 
-public class BoardWitAclDownSyncDataProvider extends BoardDataProvider {
+public class BoardWithAclDownSyncDataProvider extends BoardDataProvider {
 
     @Override
     public void goDeeper(SyncHelper syncHelper, FullBoard existingEntity, FullBoard entityFromServer, IResponseCallback<Boolean> callback) {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWithStacksAndLabelsUpSyncDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWithStacksAndLabelsUpSyncDataProvider.java
new file mode 100644
index 000000000..5f2c79ad3
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWithStacksAndLabelsUpSyncDataProvider.java
@@ -0,0 +1,37 @@
+package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.partial;
+
+import java.time.Instant;
+import java.util.Collections;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.model.full.FullBoard;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.ServerAdapter;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter;
+import it.niedermann.nextcloud.deck.persistence.sync.helpers.SyncHelper;
+import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.BoardDataProvider;
+
+public class BoardWithStacksAndLabelsUpSyncDataProvider extends BoardDataProvider {
+
+    private FullBoard board;
+
+    public BoardWithStacksAndLabelsUpSyncDataProvider(FullBoard boardToSync) {
+        board = boardToSync;
+    }
+
+    @Override
+    public List<FullBoard> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
+        return Collections.singletonList(board);
+    }
+
+    @Override
+    public void goDeeper(SyncHelper syncHelper, FullBoard existingEntity, FullBoard entityFromServer, IResponseCallback<Boolean> callback) {
+        // do nothing!
+
+    }
+
+    @Override
+    public void handleDeletes(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, List<FullBoard> entitiesFromServer) {
+        // do nothing!
+    }
+}