Use local drafts folder if needed

app/src/main/java/eu/faircode/email/AdapterFolder.java

@@ -468,7 +468,7 @@ public class AdapterFolder extends RecyclerView.Adapter<AdapterFolder.ViewHolder
                 return false;
 
             final TupleFolderEx folder = items.get(pos);
-            if (folder.tbd != null)
+            if (folder.tbd != null || folder.local)
                 return false;
 
             SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);

app/src/main/java/eu/faircode/email/BoundaryCallbackMessages.java

@@ -313,7 +313,7 @@ public class BoundaryCallbackMessages extends PagedList.BoundaryCallback<TupleMe
         boolean debug = prefs.getBoolean("debug", false);
 
         final EntityFolder browsable = db.folder().getBrowsableFolder(folder, criteria != null);
-        if (browsable == null || !browsable.selectable) {
+        if (browsable == null || !browsable.selectable || browsable.local) {
             Log.w("Boundary not browsable=" + (folder != null));
             return 0;
         }

app/src/main/java/eu/faircode/email/Core.java

@@ -182,7 +182,8 @@ class Core {
                     if (!Objects.equals(folder.id, op.folder))
                         throw new IllegalArgumentException("Invalid folder=" + folder.id + "/" + op.folder);
 
-                    if (ifolder != null && !ifolder.isOpen())
+                    if (account.protocol == EntityAccount.TYPE_IMAP &&
+                            !folder.local && ifolder != null && !ifolder.isOpen())
                         break;
 
                     // Fetch most recent copy of message
@@ -578,6 +579,8 @@ class Core {
     }
 
     private static void ensureUid(Context context, EntityFolder folder, EntityMessage message, EntityOperation op, IMAPFolder ifolder) throws MessagingException {
+        if (folder.local)
+            return;
         if (message == null || message.uid != null)
             return;
 
@@ -850,6 +853,11 @@ class Core {
         // Add message
         DB db = DB.getInstance(context);
 
+        if (folder.local) {
+            Log.i(folder.name + " local add");
+            return;
+        }
+
         // Drafts can change accounts
         if (jargs.length() == 0 && !folder.id.equals(message.folder))
             throw new IllegalArgumentException("Message folder changed");
@@ -1260,6 +1268,13 @@ class Core {
     private static void onDelete(Context context, JSONArray jargs, EntityFolder folder, EntityMessage message, IMAPFolder ifolder) throws MessagingException {
         // Delete message
         DB db = DB.getInstance(context);
+
+        if (folder.local) {
+            Log.i(folder.name + " local delete");
+            db.message().deleteMessage(message.id);
+            return;
+        }
+
         try {
             boolean deleted = false;
 
@@ -1556,8 +1571,10 @@ class Core {
         boolean sync_subscribed = prefs.getBoolean("sync_subscribed", false);
 
         // Get folder names
+        boolean drafts = false;
         Map<String, EntityFolder> local = new HashMap<>();
-        for (EntityFolder folder : db.folder().getFolders(account.id, false, false))
+        List<EntityFolder> folders = db.folder().getFolders(account.id, false, false);
+        for (EntityFolder folder : folders)
             if (folder.tbc != null) {
                 Log.i(folder.name + " creating");
                 Folder ifolder = istore.getFolder(folder.name);
@@ -1607,11 +1624,29 @@ class Core {
                 sync_folders = true;
 
             } else {
-                local.put(folder.name, folder);
+                if (EntityFolder.DRAFTS.equals(folder.type))
-                if (folder.synchronize && folder.initialize != 0)
+                    drafts = true;
-                    sync_folders = true;
+                if (!folder.local) {
+                    local.put(folder.name, folder);
+                    if (folder.synchronize && folder.initialize != 0)
+                        sync_folders = true;
+                }
             }
-        Log.i("Local folder count=" + local.size());
+        Log.i("Local folder count=" + local.size() + " drafts=" + drafts);
+
+        if (!drafts) {
+            EntityFolder d = new EntityFolder();
+            d.account = account.id;
+            d.name = context.getString(R.string.title_folder_local_drafts);
+            d.type = EntityFolder.DRAFTS;
+            d.local = true;
+            d.setProperties();
+            d.synchronize = false;
+            d.download = false;
+            d.sync_days = Integer.MAX_VALUE;
+            d.keep_days = Integer.MAX_VALUE;
+            db.folder().insertFolder(d);
+        }
 
         if (!sync_folders)
             return;

app/src/main/java/eu/faircode/email/DB.java

@@ -64,7 +64,7 @@ import static eu.faircode.email.ServiceAuthenticator.AUTH_TYPE_PASSWORD;
 // https://developer.android.com/topic/libraries/architecture/room.html
 
 @Database(
-        version = 178,
+        version = 179,
         entities = {
                 EntityIdentity.class,
                 EntityAccount.class,
@@ -1760,6 +1760,13 @@ public abstract class DB extends RoomDatabase {
                                 "  (SELECT id FROM account" +
                                 "   WHERE host IN ('imap.arcor.de'))");
                     }
+                })
+                .addMigrations(new Migration(178, 179) {
+                    @Override
+                    public void migrate(@NonNull SupportSQLiteDatabase db) {
+                        Log.i("DB migration from version " + startVersion + " to " + endVersion);
+                        db.execSQL("ALTER TABLE `folder` ADD COLUMN `local` INTEGER NOT NULL DEFAULT 0");
+                    }
                 });
     }
 

app/src/main/java/eu/faircode/email/EntityFolder.java

@@ -77,6 +77,8 @@ public class EntityFolder extends EntityOrder implements Serializable {
     @NonNull
     public Integer level = 0; // obsolete
     @NonNull
+    public Boolean local = false;
+    @NonNull
     public Boolean synchronize;
     @NonNull
     public Boolean poll = false;

app/src/main/java/eu/faircode/email/FragmentCompose.java

@@ -4343,7 +4343,8 @@ public class FragmentCompose extends FragmentBase {
                     dirty = true;
                     boolean discard_delete = prefs.getBoolean("discard_delete", false);
                     EntityFolder trash = db.folder().getFolderByType(draft.account, EntityFolder.TRASH);
-                    if (empty || trash == null || discard_delete)
+                    EntityFolder drafts = db.folder().getFolderByType(draft.account, EntityFolder.DRAFTS);
+                    if (empty || trash == null || discard_delete || (drafts != null && drafts.local))
                         EntityOperation.queue(context, draft, EntityOperation.DELETE);
                     else {
                         EntityOperation.queue(context, draft, EntityOperation.ADD);

app/src/main/java/eu/faircode/email/ServiceSynchronize.java

@@ -1466,7 +1466,8 @@ public class ServiceSynchronize extends ServiceBase implements SharedPreferences
 
                                                         // Get folder
                                                         Folder ifolder = mapFolders.get(folder); // null when polling
-                                                        boolean canOpen = (account.protocol == EntityAccount.TYPE_IMAP || EntityFolder.INBOX.equals(folder.type));
+                                                        boolean canOpen = (EntityFolder.INBOX.equals(folder.type) ||
+                                                                (account.protocol == EntityAccount.TYPE_IMAP && !folder.local));
                                                         final boolean shouldClose = (ifolder == null && canOpen);
 
                                                         try {

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

@@ -813,6 +813,7 @@
     <string name="title_folder_user_only">User folders only</string>
     <string name="title_folder_primary">Folders primary account</string>
     <string name="title_folders_unified">Unified inbox folders</string>
+    <string name="title_folder_local_drafts">Local drafts</string>
     <string name="title_no_folders">No folders</string>
     <string name="title_no_messages">No messages</string>
     <string name="title_filters_active">One or more filters active</string>