Dedup addresses

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

@@ -5506,9 +5506,9 @@ public class FragmentCompose extends FragmentBase {
 
                     // Get data
                     InternetAddress[] afrom = (identity == null ? null : new InternetAddress[]{new InternetAddress(identity.email, identity.name, StandardCharsets.UTF_8.name())});
-                    InternetAddress[] ato = MessageHelper.parseAddresses(context, to);
-                    InternetAddress[] acc = MessageHelper.parseAddresses(context, cc);
-                    InternetAddress[] abcc = MessageHelper.parseAddresses(context, bcc);
+                    InternetAddress[] ato = MessageHelper.dedup(MessageHelper.parseAddresses(context, to));
+                    InternetAddress[] acc = MessageHelper.dedup(MessageHelper.parseAddresses(context, cc));
+                    InternetAddress[] abcc = MessageHelper.dedup(MessageHelper.parseAddresses(context, bcc));
 
                     // Safe guard
                     if (action == R.id.action_send) {

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

@@ -3175,6 +3175,23 @@ public class MessageHelper {
         return addresses;
     }
 
+    static InternetAddress[] dedup(InternetAddress[] addresses) {
+        if (addresses == null)
+            return null;
+
+        List<String> emails = new ArrayList<>();
+        List<Address> result = new ArrayList<>();
+        for (InternetAddress address : addresses) {
+            String email = address.getAddress();
+            if (!emails.contains(email)) {
+                emails.add(email);
+                result.add(address);
+            }
+        }
+
+        return result.toArray(new InternetAddress[0]);
+    }
+
     static boolean isRemoved(Throwable ex) {
         while (ex != null) {
             if (ex instanceof MessageRemovedException ||