display matched and total in mailcount

Now that thread objects remember the original query, enhance the
mailcount to show the number of matched and total messages in a thread
in the search widget analogous to `notmuch search`.

The original width in the default theme was 5: two parentheses plus up
to three digits. We need to increase this 2+3+3+1=9 now (parentheses,
three digits for each of the counts, slash).

alot/db/thread.py

@@ -42,6 +42,7 @@ def refresh(self, thread=None):
     def _refresh(self, thread):
         self._total_messages = len(thread)
         self._notmuch_authors_string = thread.authors
+        self._matched_messages = thread.matched
 
         subject_type = settings.get('thread_subject')
         if subject_type == 'notmuch':
@@ -283,6 +284,10 @@ def get_total_messages(self):
         """returns number of contained messages"""
         return self._total_messages
 
+    def get_matched_messages(self):
+        """returns number of contained messages"""
+        return self._matched_messages
+
     def matches(self, query):
         """
         Check if this thread matches the given notmuch query.

alot/defaults/default.theme

@@ -62,7 +62,7 @@
         [[[mailcount]]]
             normal = 'default','','light gray','default','g66','default'
             focus = 'standout','','yellow','light gray','yellow','g58'
-            width = 'fit', 5,5
+            width = 'fit', 9,9
         [[[tags]]]
             normal = 'bold','','dark cyan','','dark cyan',''
             focus = 'standout','','yellow','light gray','yellow','g58'

alot/widgets/search.py

@@ -172,7 +172,7 @@ def prepare_date_string(thread):
 
 
 def prepare_mailcount_string(thread):
-    return "(%d)" % thread.get_total_messages()
+    return "(%d/%d)" % (thread.get_matched_messages(), thread.get_total_messages())
 
 
 def prepare_authors_string(thread):