from _xdo_cffi import ffi, lib

BUTTON_BINDINGS = [
    # left side, top to bottom
    None,
    None,
    None,
    None,

    b'a',
    b'b',
    b'c',
    b'd',

    # right side, top to bottom
    None,
    None,
    None,
    None,

    b'e',
    b'f',
    b'g',
    b'h',

    # scroll strip, up/down
    # even though the Kamvas 22 (2019) has two scroll strips, they both send
    # the same button codes
    None,
    None,
]

def main():
    xdo = lib.xdo_new(ffi.NULL)
    hidraw_path = get_tablet_hidraw()
    hidraw = open(hidraw_path, 'rb')
    while True:
        btn = get_button_press(hidraw)
        print("Got button %d" % (btn,))
        if BUTTON_BINDINGS[btn]:
            lib.xdo_send_keysequence_window(
                xdo, lib.CURRENTWINDOW, BUTTON_BINDINGS[btn], 10)


def get_tablet_hidraw():
    return '/dev/hidraw3'


BUTTON_BITS = {
    0x01: 0,
    0x02: 1,
    0x04: 2,
    0x08: 3,
    0x10: 4,
    0x20: 5,
    0x40: 6,
    0x80: 7,
}

def get_button_press(hidraw):
    while True:
        sequence = hidraw.read(12)
        # don't think there's anything we care about that doesn't start with 0xf7
        if sequence[0] != 0xf7:
            pass
        if sequence[1] == 0xe0: # buttons
            # doesn't seem like the tablet will let you push two buttons at once
            if sequence[4] > 0:
                return BUTTON_BITS[sequence[4]]
            elif sequence[5] > 0:
                # right-side buttons are 8-15, so add 8
                return BUTTON_BITS[sequence[5]] + 8
            else:
                # must be button release (all zeros)
                continue
        elif sequence[1] == 0xf0: # scroll strip
            pass # TODO: implement this


if __name__ == "__main__":
    main()