POP3 delete local hidden messages not on server anymore

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

@@ -3289,7 +3289,8 @@ class Core {
                     ifolder.fetch(imessages, ifetch);
                 }
 
-                if (!account.leave_on_device) {
+                long now = new Date().getTime();
+
                 if (hasUidl) {
                     Map<String, TupleUidl> known = new HashMap<>();
                     for (TupleUidl id : ids)
@@ -3305,8 +3306,11 @@ class Core {
                     }
 
                     for (TupleUidl uidl : known.values())
-                            if (!uidl.ui_flagged) {
-                                EntityLog.log(context, account.name + " POP purging uidl=" + uidl.uidl);
+                        if (!uidl.ui_flagged &&
+                                (!account.leave_on_device ||
+                                        (uidl.ui_hide && (uidl.ui_busy == null || uidl.ui_busy < now)))) {
+                            EntityLog.log(context, account.name + " POP purging" +
+                                    " uidl=" + uidl.uidl + " hidden=" + uidl.ui_hide);
                             db.message().deleteMessage(uidl.id);
                         }
                 } else {
@@ -3323,12 +3327,14 @@ class Core {
                     }
 
                     for (TupleUidl uidl : known.values())
-                            if (!uidl.ui_flagged) {
-                                EntityLog.log(context, account.name + " POP purging msgid=" + uidl.msgid);
+                        if (!uidl.ui_flagged &&
+                                (!account.leave_on_device ||
+                                        (uidl.ui_hide && (uidl.ui_busy == null || uidl.ui_busy < now)))) {
+                            EntityLog.log(context, account.name + " POP purging" +
+                                    " msgid=" + uidl.msgid + " hidden=" + uidl.ui_hide);
                             db.message().deleteMessage(uidl.id);
                         }
                 }
-                }
 
                 boolean _new = true;
                 for (int i = reversed ? 0 : imessages.length - 1; reversed ? i < max : i >= imessages.length - max; i += reversed ? 1 : -1) {