i3n-bar

#!/usr/bin/env python


import argparse
import sys
import getpass

import i3
import zmq


# Enable daemon mode on Subscription thread:
i3.Subscription.daemon = True


instance = None
debug_enabled = False


def display(msg):
    """ Display a text on stdout and flush it.
    """
    sys.stdout.write('%s\n' % msg)
    sys.stdout.flush()
    debug('Display: %r' % msg)


def debug(msg):
    """ Print debug text on stderr.
    """
    if debug_enabled:
        line = u'[i3n-daemon/%s] %s\n' % (instance, msg)
        sys.stderr.write(line.encode('utf-8'))


def get_current_workspace():
    """ Get the current focused workspace.
    """
    workspaces = [w for w in i3.get_workspaces() if w['focused']]
    assert len(workspaces) == 1, 'Only one workspace should be focused at once'
    return workspaces[0]


def main(args):
    debug(u'i3n daemon is running')
    annotations = {}  # Store annotations for each workspace

    def cb_workspace_change(event, data, subscription):
        """ Callback used when a current workspace is changed.
        """
        data = [w for w in data if w['visible'] and w['output'] == args.output]
        assert len(data) == 1, 'only 1 workspace should match'
        workspace = data[0]
        debug(u'Changed workspace to %s' % workspace['name'])
        display(annotations.get(workspace['name'], ' '))

    i3.Subscription(cb_workspace_change, 'workspace')

    context = zmq.Context()
    if args.slave:
        # Socket used to receive updates from master:
        socket = context.socket(zmq.SUB)
        socket.connect('ipc://%s.slave' % args.ipc)
    else:
        # Socket used to receive updates from client:
        socket = context.socket(zmq.SUB)
        socket.bind('ipc://%s' % args.ipc)

        # Socket used to relay updates to slaves:
        socket_relay = context.socket(zmq.PUB)
        socket_relay.bind('ipc://%s.slave' % args.ipc)

    socket.setsockopt(zmq.SUBSCRIBE, '')

    while True:
        msg = socket.recv_json()
        debug(u'Received message: %r' % msg)
        if msg['type'] == u'set':
            annotations[msg['workspace']] = msg['annotation']
            cur_workspace = get_current_workspace()
            if msg['workspace'] == cur_workspace['name'] and args.output == cur_workspace['output']:
                display(msg['annotation'])
        # Relay message to slave instances:
        if not args.slave:
            debug('Message relayed to slaves')
            socket_relay.send_json(msg)


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('output')
    parser.add_argument('--ipc', default='/tmp/i3n-%s' % getpass.getuser())
    parser.add_argument('--slave', action='store_true', default=False)
    parser.add_argument('-d', '--debug', action='store_true', default=False)
    args = parser.parse_args()
    instance = args.output
    debug_enabled = args.debug
    try:
        main(args)
    except Exception as err:
        debug(u'Fatal error:')
        raise