import os, subprocess, shlex

cmd_debug_events = 'libinput debug-events'
cmd_list_devices = 'libinput list-devices'
cmd_dev_kernel = ''

def run(cmd, check=True):
    'Run subprocess function and return standard output or None'
    # Maintain subprocess compatibility with python 3.4 so use
    # check_output() rather than run().
    try:
        stdout = subprocess.check_output(cmd, universal_newlines=True,
                stderr=(None if check else subprocess.DEVNULL))
    except Exception as e:
        stdout = None
        if check:
            print(str(e), file=sys.stderr)

    return stdout

def get_devices_list():
    'Get list of devices and their attributes (as a dict) from libinput'
    stdout = run(cmd_list_devices.split())

    if stdout:
        dev = {}
        for line in stdout.splitlines():
            line = line.strip()
            if line and ':' in line:
                key, value = line.split(':', maxsplit=1)
                dev[key.strip().lower()] = value.strip()
            elif dev:
                yield dev
                dev = {}

for dev in get_devices_list():
    if dev['device'].find('Touchpad') >= 0:
        cmd_dev_kernel = '--device {}'.format(dev['kernel'])
        break


X_SENS = 60
X_INTERVAL = 60
Y_SENS = 50
Y_INTERVAL = 40

class Gesture:
    def __init__(self):
        self.alt_down = False
        self.clear()

    def begin(self, num):
        self.clear()
        self.num_of_point = num

    def clear(self):
        self.num_of_point = 0
        self.direct = 0
        self.clear_point()

        if self.alt_down:
            os.system('xdotool keyup alt')
        self.alt_down = False


    def clear_point(self):
        self.move_x_axis = self.move_y_axis = 0

    def add_point(self, x, y):
        self.move_x_axis += x
        self.move_y_axis += y
        self.classification()

    def classification(self):
        direct = 0
        #check continous
        if self.move_y_axis < -Y_INTERVAL:
            direct = 1
        elif self.move_y_axis > Y_INTERVAL:
            direct = 2
        if self.move_x_axis < -X_INTERVAL:
            direct = 3
        elif self.move_x_axis > X_INTERVAL:
            direct = 4

        if direct and  direct == self.direct:
            self.c_move(direct)
            return

        direct = 0
        #check first movement
        if self.move_y_axis < -Y_SENS:
            direct = 1
        elif self.move_y_axis > Y_SENS:
            direct = 2
        if self.move_x_axis < -X_SENS:
            direct = 3
        elif self.move_x_axis > X_SENS:
            direct = 4

        if direct:
            self.s_move(direct)
            return

    def c_move(self, direct):
        self.clear_point()
        self.direct = direct
        print('c', self.direct)

        if self.num_of_point == 4:
            if direct == 3:
                os.system('xdotool key Shift+Tab')
            elif direct == 4:
                os.system('xdotool key Tab')

    def s_move(self, direct):
        self.clear_point()
        prev_direct = self.direct
        self.direct = direct

        print('s', self.direct)
        if self.num_of_point == 3:
            if direct == 3:
                os.system('xdotool key alt+Right')
                self.clear()
            elif direct == 4:
                os.system('xdotool key alt+Left')
                self.clear()
        elif self.num_of_point == 4:
            if direct == 1: #up
                self.clear()
                os.system('xdotool key ctrl+alt+Up')
            elif direct == 2:
                self.clear()
                os.system('xdotool key ctrl+alt+Down')
            elif direct == 3:
                os.system('xdotool keydown alt key Shift+Tab')
                self.alt_down = True
            elif direct == 4:
                os.system('xdotool keydown alt key Tab')
                self.alt_down = True

if cmd_dev_kernel:
    command = 'stdbuf -oL -- {} {}'.format(cmd_debug_events, cmd_dev_kernel)
    cmd = subprocess.Popen(shlex.split(command), stdout=subprocess.PIPE,
            bufsize=1, universal_newlines=True)

    gesture = Gesture()

    while True:
        for line in cmd.stdout:
            try:

                line = line.strip().split()
                if line[1] == 'GESTURE_SWIPE_END':
                    gesture.clear()

                elif line[1] == 'GESTURE_SWIPE_BEGIN':
                    gesture.begin(int(line[3]))

                elif line[1] == 'GESTURE_SWIPE_UPDATE':
                    acc_x, acc_y = ''.join(line[4:]).split('(')[0].split('/')[:2]
                    acc_x, acc_y = float(acc_x), float(acc_y)

                    gesture.add_point(acc_x, acc_y)
            except Exception as e:
                print(e)
                gesture.clear()
            # os.system('xdotool keyup alt')