Application Switching and Launch Utility

wintool.py

#! /usr/bin/env python3
"""
USAGE:

1. Put this script somewhere on yout path
2. Assign a keyboard shortcut for opening this script with for your target
   application, e.g.
        Ctrl-Alt-Shift-1 to launch "wintool chrome"
3. Defaults are provided in the APP_PATHS, modify as necessary

Operation:

3 possible behaviors are possible with this script, depending on what
application windows are currently open on the user's desktop.
Using chrome for example:

    a. no chrome windows currently open: launches chrome
    b. chrome windows open, user not focused on a chrome window: focuses on a
       chrome window
    c. user focused on a chrome window: focuses on next chrome window
"""

import os
import re
import subprocess
import sys
from collections import namedtuple

# dictionary of app string: command line invocation of executable
# the app string is provided as the first argument to the command line, e.g.
# wintool chrome
# NOTE: the app string should be a case insensitive substring of the target
# application's WM_CLASS
APP_PATHS = {
    # terminal
    "tilix": "tilix",
    "vim": "gvim",
    "emacs": "emacs",
    # chrome, replace with desired chrome executable
    "chrome": "google-chrome-unstable",
    # music player
    "deadbeef": "deadbeef",
    # file manager
    "nemo": "nemo",
}

Window = namedtuple("Window", ["wid", "wm_class", "title"])


def cmd_output(s):
    # returns the output of the given cmd in lines
    return subprocess.check_output(s.split()).decode("utf-8").splitlines()


def get_app_windows(app=None):
    if app:
        app = app.lower()

    for line in cmd_output("wmctrl -lx"):
        [wid, _, wm_class, _, title] = re.split(r"\s+", line, 4)

        # not interested in desktop
        if title == "Desktop":
            continue

        # perform further filtering by app if necessary
        if app and app not in wm_class.lower():
            continue

        # wids are in hexadecimal
        yield Window(int(wid, 16), wm_class, title)


def get_active_wid():
    # wid for xdotool is in decimal
    return int(cmd_output("xdotool getwindowfocus")[0])


if __name__ == "__main__":
    # not enough args
    if len(sys.argv) == 1:
        exit()

    app = sys.argv[1].lower()

    # get the wid of the current window
    active_wid = get_active_wid()

    app_windows = list(get_app_windows(app))
    if not app_windows:
        # unknown app, exit
        if app not in APP_PATHS:
            exit()

        # launch the program
        os.system(APP_PATHS[app])

    # is current window of the requested type
    focused_idx = None
    for i, w in enumerate(app_windows):
        if w.wid == active_wid:
            focused_idx = i
            break

    if focused_idx is None:
        # focus on first window of requested type
        target_idx = 0
    else:
        # only window open, noop
        if len(app_windows) == 1:
            exit()

        # focus on next window of requested type (with wraparound)
        target_idx = (i + 1) % len(app_windows)

    # do the actual window switching
    subprocess.Popen(["wmctrl", "-ia", str(app_windows[target_idx].wid)])