This is a proposal for a terminal gui for notmuch mail, written in python.
The key ideas are:

* aim at the look and feel of sup for now
* lock the index only when needed
* use libraries whenever possible. 
  urwid: http://excess.org/urwid/ CAUTION: you need the dev-version!
  The notmuch bindings: https://bitbucket.org/spaetz/cnotmuch/
  (mailbox: http://docs.python.org/library/mailbox.html)
  (configparser)

You need the notmuch python bindings and urwid to run it. While developing,
I run it like this 
> python alot/init.py -l debug.log -d debug
and "tail -f debug.log" in another window.
If installed via the setup.py, "alot" should be in your path.

You can find some screenshots in data/alot*png

---------------------------------------
At the moment you can play with the global bindings
I, open inbox
U, open unread 
s, python shell
L, open taglist
\, prompts and stars search
v, opens log in vim
x, closes current buffer
tab, tabs between buffers
;, opens bufferlist
:, opens cmd shell
@, refreshes current buffer
m, compose mail


In all views, arrows, page-up/down, j,k and space can be used to move the focus.
escape will close the shell or cancel prompts.
Here the buffer-specific bindings:

Searchbuffer: 
enter, opens single thread view for select thread,
a, toggles "inbox" tag
&, toggles "killed" tag
|, prompts for query refinement
l, manually change labels

Single thread:
a, toggles "inbox" tag
h, toggles show header (all fields from settings displayed_headers)
enter, toggles body (folds awas msg)

Bufferlist: 
d, removes selected buffer, 
enter, focus selected.

Taglist:
enter, opens new search view for selected tag

Envelope:
y, send mail
------------------------------

Here is an overview of the current architecture.

alot.ui.UI 
contains the main component: it
 - handles the urwid.MainLoop that manages the screen etc.
 - contains a logging.logger that can be used for log/debug messages like so:
   ui.logger.info('hello logworld')
 - sets up and updates the header/footer/body widgets
 - is able to open/close/focus buffers (there's a list ui.buffers of currently
   known buffers, and a ui.current_buffer, pointing to the focussed one)
 - handles global keybindings. See below for more on bindings.
 - can apply (and further down the road undo/redo) commands (see command.py)
 - is able to open a prompt/dialogs/shell

alot.db.DBManager 
interface to the notmuch index. Currently, it has very limited functionality,
but should be able to to this:
 - store the connection settings (index path and whether or not we use a
   read_only connection..)
 - create notmuch.Query objects for read access on demand
 - maintains a write-queue for write access to the index.
alot.db also contains wrapper classes for notmuch.Thread and notmuch.Messages
that are used throughout the interface.

alot.buffer.Buffer
Is used as a base class for different types of buffers, or display-modi if you
like. Technically, Buffer inherits from urwid.Widget so that it can be directly 
set as the body-part of the urwid main gui, thereby intercepting 
(and filter/handle according to local bindings) the
key presses. A Buffer
 - is a widget, that can be drawn,focussed etc as all widgets.
 - has a pointer to the main ui, a typename, (e.g. search results, display
   single thread, envelope, logmode) and knows how to summarise itself.
 - knows how to handle local (mode-specific) keybindings (self.bindings see
   below)

alot.commands.Command
A base class for different commands. A command is an object that
represents an atomic action. It will only be be applied once (and is then
stored in a undo-list somewhere). It
 - has a typename, that is used to identify a type of command for the command
   factory
 - can be applied using cmd.apply with a fixed interface: I  assume we want at
   least pointers to the main ui and the dbman objects here
 - should contain a help-info about what it does (to automagically create
   dynamic help-buffers later on)
 - should know if its undoable, and if so, implement undo() and redo()
 - points to pre and post hooks. This might get tricky with undoable cmds.. The
   idea is, that a cmd gets applied (see ng.ui.UI.apply_command), also its pre
   and posthooks are called if defined. These should have the same signature as
   cmd.apply(). See settings.hooks for an example.  There's a number of
   commands i already implemented. Each one should be created by the
   ng.command.factory (which also attaches the hooks)

alot.widgets
contains the urwid.Widgets i use do draw notmuch objects. There's a Threadline
widget for example, that knows how to present a notmuch.thread object as a
textline. Should be pretty self explanatory, definitely needs some love.  These
inherit from AttrMap, which is not very clean i guess, but they must be
"selectable" so that we can use them in a urwid.ListBox (which displays a list
and can focus elements). Since ThreadlineWidget is selectable it must include a
dummy keypress method.

alot.walker
Contains urwid.ListWalker derived classes that implement a listwalker (the
content-part of a urwid.ListBox widget) that dynamically allocates its content.
The thing is that if one makes a query for all threads in the index and naively
creating a ng.widgets.ThreadlineWidget for each and placing them in a
urwid.Listbox (actually a urwid.SimplieListWalker, and /that/ in a listbox),
this will potentially eat up your memory and take a long time. So
alot.walker.IteratorWalker will dynamically create its next element from the next
element of the iterator. 

Key Bindings
Are currently a hash in objects of the classes ng.ui.UI and ng.buffer.Buffer.
Obviously, a key is first handed to the current buffer and in case it doesn't
handle it, it will be handled by the main UI. Each buffer-subclass comes with
its own default local bindings which we might want to overwrite at some point.
I guess we should have a "map" command that takes a buffertype, a key and
something to call.  For now, a key in the binding hash is a string that
represents a keypress (urwid style: 'shift j', 'k' etc are valid).  The value
is then a pair of (commandtypestring, parameterhash), that is used by the
command.factory to instantiate a command with of type commandtypestring with
parameters parameterhash. Values in the parameterhash will be called at cmd
creation by command.factory if callable. See self.bindings in
alot.buffer.BufferListBuffer for an example.

Sending mail:
ComposeMailCommand implements what happens when you hit 'm':
depending on your settings, it will use ui.prompt to prompt for 
From,To and Subject headers, calls the editor (set editor_spawn to True to do this asynchronously).
Afterwards, it opens an buffer.EnvelopeBuffer that displays your email.

alot.command.SendMailCommand tries to send a given email:
it selects an alot.accounts.Account depending on the from-header
and hands the mail to that accounts send.Sender.send_mail().

Accounts:
alot.accounts.Account objects capture info for one email account:
realname, address, gpg fingerprint, and a alot.send.Sender instance
that is used to send out mail from this account.

Sender:
instances of this class know how to send mail:
they implement a send_mail(mail) method that takes an email.Message object
and sends it. In case the sender is instanciated with a mailbox object
it will store sent mails in that mailbox.Mailbox.
For now, there is only a SendmailSender subclass, that sends your mail
using an external tool. 

See data/ecample.rc for how to define accounts: all
sections whose name starts with "account " are taken to define an account.
If you use SendMailCommand to send mails, it will look for an account where
the address property matches the from-header of that mail.

Hooks
this should later on include methods that look for and call hooks. The idea
is that a user might define either python callables or paths to binaries, and
alot.hooks.get_hook(hookname) retrieves them so that they can be placed in
commands. 
UPDATE: this is currently implemented in alot/settings.py.
See data/example_hooks.py and data/example.rc for how to add your hooks