Fix POP3 uidls

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

@@ -1536,12 +1536,14 @@ class Core {
             List<TupleUidl> ids = db.message().getUidls(folder.id);
             Log.i(folder.name + " POP existing=" + ids.size());
 
+            // Map identifiers
             Map<String, TupleUidl> uidls = new HashMap<>();
+            Map<String, TupleUidl> msgids = new HashMap<>();
             for (TupleUidl id : ids)
-                if (id.uidl == null)
-                    db.message().deleteMessage(id.id);
-                else
+                if (id.uidl != null)
                     uidls.put(id.uidl, id);
+                else if (id.msgid != null)
+                    msgids.put(id.msgid, id);
 
             for (Message imessage : imessages)
                 try {
@@ -1560,10 +1562,19 @@ class Core {
 
                     if (uidls.containsKey(uidl)) {
                         uidls.remove(uidl);
-                        Log.i(folder.name + " POP having=" + uidl);
+                        Log.i(folder.name + " POP having uidl=" + uidl);
                         continue;
                     }
 
+                    if (caps.containsKey("UIDL")) {
+                        String msgid = helper.getMessageID();
+                        if (msgids.containsKey(msgid)) {
+                            Log.i(folder.name + " POP having msgid=" + msgid);
+                            db.message().setMessageUidl(msgids.get(msgid).id, uidl);
+                            continue;
+                        }
+                    }
+
                     try {
                         Log.i(folder.name + " POP sync=" + uidl);
 

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

@@ -664,10 +664,12 @@ public interface DaoMessage {
     @Query("UPDATE message SET ui_found = 0")
     int resetSearch();
 
-    @Query("UPDATE message SET ui_snoozed = :wakeup" +
-            " WHERE id = :id")
+    @Query("UPDATE message SET ui_snoozed = :wakeup WHERE id = :id")
     int setMessageSnoozed(long id, Long wakeup);
 
+    @Query("UPDATE message SET uidl = :uidl WHERE id = :id")
+    int setMessageUidl(long id, String uidl);
+
     @Query("UPDATE message SET notifying = 0")
     int clearNotifyingMessages();