thread: drop the use of urwidtrees

Their API is misdesigned - forces the use of trees for nontree objects
and mixes data relationships with display properties. The result is a
mess that is hard to understand/maintain/extend.

Replace the use of urwidtrees with urwid Pile and ListBox. This
temporarily removes tree-style indentation and decorations for thread
buffers. That will be reimplemented in following commits.

1 files changed, 10 insertions, 6 deletions

diff --git a/alot/db/message.py b/alot/db/message.py
index f9e8e37b..62b85788 100644
--- a/alot/db/message.py
+++ b/alot/db/message.py
@@ -35,24 +35,28 @@ class Message:
     """value of the Message-Id header (str)"""
     id = None
 
+    """this message's depth in the thread tree"""
+    depth = None
+
     """A list of replies to this message"""
     replies = None
 
-    def __init__(self, dbman, msg, thread, replies):
+    def __init__(self, dbman, thread, msg, depth):
         """
         :param dbman: db manager that is used for further lookups
         :type dbman: alot.db.DBManager
-        :param msg: the wrapped message
-        :type msg: notmuch.database.Message
         :param thread: this messages thread
         :type thread: :class:`~alot.db.Thread`
-        :param replies: a list of replies to this message
-        :type replies alot.db.message.Message
+        :param msg: the wrapped message
+        :type msg: notmuch.database.Message
+        :param depth: depth of this message in the thread tree (0 for toplevel
+                      messages, 1 for their replies etc.)
+        :type depth int
         """
         self._dbman = dbman
         self.id = msg.get_message_id()
         self.thread = thread
-        self.replies = replies
+        self.depth   = depth
         try:
             self.date = datetime.fromtimestamp(msg.get_date())
         except ValueError: