mail/reply: rewrite recipient selection

Thoroughly ensure that To+Cc contains neither our own address (except
when it is wanted) nor any duplicates.

Use structured headers provided by email.headerregistry to simplify
dealing with addr-spec vs. mailbox (display name + <addr-spec>).

1 files changed, 14 insertions, 0 deletions

diff --git a/alot/db/message.py b/alot/db/message.py
index 97ab991f..01d7c7f1 100644
--- a/alot/db/message.py
+++ b/alot/db/message.py
@@ -119,6 +119,20 @@ class _MessageHeaders:
                 return []
             raise
 
+    def pick_addrlist_header(self, *args):
+        """
+        Given a list of "address-list" header names as positional arguments,
+        return the addresses from the first one that is present.
+
+        :returns: addresses from the first existing header, or an empty tuple
+        :rtype: tuple(headerregistry.Address)
+        """
+        for h in args:
+            if h in self:
+                return self.get(h).addresses
+
+        return ()
+
 class _MimeTree:
     _part = None