import asyncio, evdev
import itertools
import subprocess

KEY_SPACE = 57
KEY_SYM = 162

keys_pressed = {
    KEY_SPACE: 0,
    KEY_SYM: 0,
}

layouts = ['us', 'ru']
cmd = "dconf write /desktop/lipstick-jolla-home/layout '{layout_code}'"

@asyncio.coroutine
def layout_switcher(device):
    layouts_pool = itertools.cycle(layouts)

    layout_code = next(layouts_pool)
    print('Current layout is {}'.format(layout_code))
    set_layout(layout_code)

    while True:
        events = yield from device.async_read()
        for event in events:
            if event.type == evdev.ecodes.EV_KEY:
                # Sym + space
                if event.code in (KEY_SPACE, KEY_SYM):
                    keys_pressed[event.code] = event.value

        if keys_pressed[KEY_SPACE] and keys_pressed[KEY_SYM]:
            layout_code = next(layouts_pool)
            print('Switching keyboard layout to {}'.format(layout_code))
            set_layout(layout_code)

def set_layout(layout_code):
    layout_cmd = cmd.format(layout_code=layout_code).split()
    subprocess.call(layout_cmd)

keybd = evdev.InputDevice('/dev/input/event3')
asyncio.async(layout_switcher(keybd))

loop = asyncio.get_event_loop()
loop.run_forever()