#!/usr/bin/python3

import subprocess
import argparse
import os
import re
import sys
import fcntl

# Good enough for now :/.

# TODO(ish):
#
# Make assorted detection hacks cleaner.
# Profile and optimize.
# Consider reimplmenting in perl or C.
# Produce more useful error messages :P.

CONFIG_PATH = os.getenv('HOME')+'/.config/keyd/app.conf'
LOCKFILE = os.getenv('HOME')+'/.config/keyd/lockfile'
LOGFILE = os.getenv('HOME')+'/.config/keyd/log'

def die(msg):
    sys.stderr.write('ERROR: ')
    sys.stderr.write(msg)
    sys.stderr.write('\n')
    exit(0)

def assert_env(var):
    if not os.getenv(var):
        raise Exception(f'Missing environment variable {var}')

def run_or_die(cmd, msg=''):
    rc = subprocess.run(['/bin/sh', '-c', cmd],
            stdout=subprocess.DEVNULL,
            stderr=subprocess.DEVNULL).returncode

    if rc != 0:
        die(msg)

def parse_config(path):
    map = {}

    for line in open(path):
        line = line.strip()

        if line.startswith('[') and line.endswith(']'):
            window_class = line[1:-1]

            bindings = []
            map[window_class] = bindings
        elif line == '':
            continue
        elif line.startswith('#'):
            continue
        else:
            bindings.append(line)

    return map

class SwayMonitor():
    def __init__(self, on_window_change):
        assert_env('SWAYSOCK')

        self.on_window_change = on_window_change

    def init(self):
        pass

    def run(self):
        import json
        import subprocess

        swayproc = subprocess.Popen(
            ['swaymsg',
                '--type',
                'subscribe',
                '--monitor',
                '--raw',
                '["window"]'], stdout=subprocess.PIPE)

        for ev in swayproc.stdout:
            data = json.loads(ev)

            try:
                if data['container']['focused'] == True:
                    cls = data['container']['window_properties']['class']
                    self.on_window_change(cls)
            except:
                cls = data['container']['app_id']
                self.on_window_change(cls)
                pass


class XMonitor():
    def __init__(self, on_window_change):
        assert_env('DISPLAY')

        self.on_window_change = on_window_change

    def init(self):
        import Xlib
        import Xlib.display

        self.dpy = Xlib.display.Display()
        self.dpy.screen().root.change_attributes(
            event_mask = Xlib.X.SubstructureNotifyMask|Xlib.X.PropertyChangeMask)

    def run(self):
        last_active_class = ""
        while True:
            self.dpy.next_event()

            try:
                wm_class = self.dpy.get_input_focus().focus.get_wm_class()
                if wm_class:
                    cls = wm_class[1]
                    if cls != last_active_class:
                        last_active_class = cls
                        self.on_window_change(cls)
            except:
                import traceback
                traceback.print_exc()
                pass

# :(
class GnomeMonitor():
    def __init__(self, on_window_change):
        assert_env('GNOME_SETUP_DISPLAY')

        self.on_window_change = on_window_change

        self.extension_dir = os.getenv('HOME') + '/.local/share/gnome-shell/extensions/keyd'
        self.fifo_path = self.extension_dir + '/keyd.fifo'

    def _install(self):
        os.makedirs(self.extension_dir, exist_ok=True)

        extension = '''
        const Shell = imports.gi.Shell;

        // We have to keep an explicit reference around to prevent garbage collection :/.
        let file = imports.gi.Gio.File.new_for_path('%s');
        let pipe = file.append_to_async(0, 0, null, on_pipe_open);

        function send(msg) {
            if (!pipe)
                return;

            try {
                pipe.write(msg, null);
            } catch {
                log('pipe closed, reopening...');
                pipe = null;
                file.append_to_async(0, 0, null, on_pipe_open);
            }
        }

        function on_pipe_open(file, res) {
            log('pipe opened');
            pipe = file.append_to_finish(res);
        }

        function init() {
                Shell.WindowTracker.get_default().connect('notify::focus-app', () => {
                    send(`${global.display.focus_window.get_wm_class()}\n`);
                });

                return { enable: ()=>{}, disable: ()=>{} };
        }
        ''' % (self.fifo_path)

        metadata = '''
        {
                "name": "keyd",
                "description": "Used by keyd to obtain active window information.",
                "uuid": "keyd",
                "shell-version": [ "41" ]
        }
        '''

        open(self.extension_dir + '/metadata.json', 'w').write(metadata)
        open(self.extension_dir + '/extension.js', 'w').write(extension)
        os.mkfifo(self.fifo_path)

    def init(self):
        if not os.path.exists(self.extension_dir):
            print('keyd extension not found, installing...')
            self._install()
            print('Success! Please restart Gnome and rerun this script.')
            exit(0)

        run_or_die('gsettings set org.gnome.shell disable-user-extensions false');
        run_or_die('gnome-extensions enable keyd', 'Failed to enable keyd extension.')

    def run(self):
        for cls in open(self.fifo_path):
            cls = cls.strip()
            self.on_window_change(cls)

def get_monitor(on_window_change):
    monitors = [
        ('Sway', SwayMonitor),
        ('Gnome', GnomeMonitor),
        ('X', XMonitor),
    ]

    for name, mon in monitors:
        try:
            m = mon(on_window_change)
            print(f'{name} detected')
            return m
        except:
            pass

    print('Could not detect app environment :(.')
    sys.exit(-1)

def lock():
    global lockfh
    lockfh = open(LOCKFILE, 'w')
    try:
        fcntl.flock(lockfh, fcntl.LOCK_EX | fcntl.LOCK_NB)
    except:
        die('only one instance may run at a time')

def ping_keyd():
    run_or_die('keyd -e ping',
'could not connect to keyd instance, make sure it is running and you are a member of `keyd`')

def daemonize():
    print('Daemonizing...')

    fh = open(LOGFILE, 'w')

    os.close(1)
    os.close(2)
    os.dup2(fh.fileno(), 1)
    os.dup2(fh.fileno(), 2)

    if os.fork(): exit(0)
    if os.fork(): exit(0)

opt = argparse.ArgumentParser()
opt.add_argument('-v', '--verbose', default=False, action='store_true', help='print window class names in real time (useful for debugging and discovering window classes)')
opt.add_argument('-d', '--daemonize', default=False, action='store_true', help='fork and run in the background')
args = opt.parse_args()

if not os.path.exists(CONFIG_PATH):
    die('could not find app.conf, make sure it is in ~/.config/keyd/app.conf')

bindings = parse_config(CONFIG_PATH)
ping_keyd()
lock()

def normalize_class(s):
     return re.sub('[^A-Za-z0-9]', '-', s).strip('-').lower()

last_mtime = os.path.getmtime(CONFIG_PATH)
def on_window_change(cls):
    global last_mtime
    global bindings

    cls = normalize_class(cls)
    mtime = os.path.getmtime(CONFIG_PATH)

    if mtime != last_mtime:
        print(CONFIG_PATH + ': Updated, reloading config...')
        bindings = parse_config(CONFIG_PATH)
        last_mtime = mtime

    if args.verbose:
        print(f'Active window class: {cls}')

    if cls in bindings:
        # Apply the bindings.
        subprocess.run(['keyd', '-e', *bindings[cls]])


mon = get_monitor(on_window_change)
mon.init()

if args.daemonize:
    daemonize()

mon.run()