be more careful with corner cases when mentioning multiple people

1 files changed, 33 insertions, 0 deletions

diff --git a/src/main/java/de/pixart/messenger/utils/NickValidityChecker.java b/src/main/java/de/pixart/messenger/utils/NickValidityChecker.java
new file mode 100644
index 000000000..0b4df771f
--- /dev/null
+++ b/src/main/java/de/pixart/messenger/utils/NickValidityChecker.java
@@ -0,0 +1,33 @@
+package de.pixart.messenger.utils;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.List;
+
+import de.pixart.messenger.entities.Conversation;
+import de.pixart.messenger.xmpp.jid.InvalidJidException;
+import de.pixart.messenger.xmpp.jid.Jid;
+
+public class NickValidityChecker {
+
+    private static boolean check(final Conversation conversation, final String nick) {
+        Jid room = conversation.getJid();
+        try {
+            Jid full = Jid.fromParts(room.getLocalpart(), room.getDomainpart(), nick);
+            return conversation.hasMessageWithCounterpart(full)
+                    || conversation.getMucOptions().findUserByFullJid(full) != null;
+        } catch (InvalidJidException e) {
+            return false;
+        }
+    }
+
+    public static boolean check(final Conversation conversation, final List<String> nicks) {
+        Set<String> previousNicks = new HashSet<>(nicks);
+        for(String previousNick : previousNicks) {
+            if (!NickValidityChecker.check(conversation,previousNick)) {
+                return false;
+            }
+        }
+        return true;
+    }
+}
\ No newline at end of file