I didn't like the polling approach, so I did some digging on bluez and DBus. I ended up writing the following script:

#!/usr/bin/python



import dbus

from dbus.mainloop.glib import DBusGMainLoop

import gobject



import subprocess



# ID of the device we care about

DEV_ID = '00_1D_54_AB_DC_72'



dbus_loop = DBusGMainLoop()

bus = dbus.SystemBus(mainloop=dbus_loop)



# Figure out the path to the headset

man = bus.get_object('org.bluez', '/')

iface = dbus.Interface(man, 'org.bluez.Manager')

adapterPath = iface.DefaultAdapter()



headset = bus.get_object('org.bluez', adapterPath + '/dev_' + DEV_ID)

    # ^^^ I'm not sure if that's kosher. But it works.



def cb(iface=None, mbr=None, path=None):



    if ("org.bluez.Headset" == iface and path.find(DEV_ID) > -1):

        print 'iface: %s' % iface

        print 'mbr: %s' % mbr

        print 'path: %s' % path

        print "

"

        print "matched"



        if mbr == "Connected":

            subprocess.call(["clementine", "--play"])

            print 'conn'



        elif mbr == "Disconnected":

            subprocess.call(["clementine", "--stop"])

            print 'dconn'



headset.connect_to_signal("Connected", cb, interface_keyword='iface', member_keyword='mbr', path_keyword='path')

headset.connect_to_signal("Disconnected", cb, interface_keyword='iface', member_keyword='mbr', path_keyword='path')



loop = gobject.MainLoop()

loop.run()