dotfiles/hm/desktop/frobar/frobar/updaters.py

#!/usr/bin/env python3

import functools
import logging
import math
import os
import threading
import time

import coloredlogs
import i3ipc
import pyinotify

from frobar.display import Element
from frobar.common import notBusy

coloredlogs.install(level="DEBUG", fmt="%(levelname)s %(message)s")
log = logging.getLogger()

# TODO Sync bar update with PeriodicUpdater updates


class Updater:
    @staticmethod
    def init() -> None:
        PeriodicUpdater.init()
        InotifyUpdater.init()
        notBusy.set()

    def updateText(self, text: Element) -> None:
        print(text)

    def fetcher(self) -> Element:
        return "{} refreshed".format(self)

    def __init__(self) -> None:
        self.lock = threading.Lock()

    def refreshData(self) -> None:
        # TODO OPTI Maybe discard the refresh if there's already another one?
        self.lock.acquire()
        try:
            data = self.fetcher()
        except BaseException as e:
            log.error(e, exc_info=True)
            data = ""
        self.updateText(data)
        self.lock.release()


class PeriodicUpdaterThread(threading.Thread):
    def run(self) -> None:
        # TODO Sync with system clock
        counter = 0
        while True:
            notBusy.set()
            if PeriodicUpdater.intervalsChanged.wait(
                timeout=PeriodicUpdater.intervalStep
            ):
                # ↑ sleeps here
                notBusy.clear()
                PeriodicUpdater.intervalsChanged.clear()
                counter = 0
                for providerList in PeriodicUpdater.intervals.copy().values():
                    for provider in providerList.copy():
                        provider.refreshData()
            else:
                notBusy.clear()
                assert PeriodicUpdater.intervalStep is not None
                counter += PeriodicUpdater.intervalStep
                counter = counter % PeriodicUpdater.intervalLoop
                for interval in PeriodicUpdater.intervals.keys():
                    if counter % interval == 0:
                        for provider in PeriodicUpdater.intervals[interval]:
                            provider.refreshData()


class PeriodicUpdater(Updater):
    """
    Needs to call :func:`PeriodicUpdater.changeInterval` in `__init__`
    """

    intervals: dict[int, set["PeriodicUpdater"]] = dict()
    intervalStep: int | None = None
    intervalLoop: int
    updateThread: threading.Thread = PeriodicUpdaterThread(daemon=True)
    intervalsChanged = threading.Event()

    @staticmethod
    def gcds(*args: int) -> int:
        return functools.reduce(math.gcd, args)

    @staticmethod
    def lcm(a: int, b: int) -> int:
        """Return lowest common multiple."""
        return a * b // math.gcd(a, b)

    @staticmethod
    def lcms(*args: int) -> int:
        """Return lowest common multiple."""
        return functools.reduce(PeriodicUpdater.lcm, args)

    @staticmethod
    def updateIntervals() -> None:
        intervalsList = list(PeriodicUpdater.intervals.keys())
        PeriodicUpdater.intervalStep = PeriodicUpdater.gcds(*intervalsList)
        PeriodicUpdater.intervalLoop = PeriodicUpdater.lcms(*intervalsList)
        PeriodicUpdater.intervalsChanged.set()

    @staticmethod
    def init() -> None:
        PeriodicUpdater.updateThread.start()

    def __init__(self) -> None:
        Updater.__init__(self)
        self.interval: int | None = None

    def changeInterval(self, interval: int) -> None:

        if self.interval is not None:
            PeriodicUpdater.intervals[self.interval].remove(self)

        self.interval = interval

        if interval not in PeriodicUpdater.intervals:
            PeriodicUpdater.intervals[interval] = set()
        PeriodicUpdater.intervals[interval].add(self)

        PeriodicUpdater.updateIntervals()


class InotifyUpdaterEventHandler(pyinotify.ProcessEvent):
    def process_default(self, event: pyinotify.Event) -> None:
        assert event.path in InotifyUpdater.paths

        if 0 in InotifyUpdater.paths[event.path]:
            for provider in InotifyUpdater.paths[event.path][0]:
                provider.refreshData()

        if event.name in InotifyUpdater.paths[event.path]:
            for provider in InotifyUpdater.paths[event.path][event.name]:
                provider.refreshData()


class InotifyUpdater(Updater):
    """
    Needs to call :func:`PeriodicUpdater.changeInterval` in `__init__`
    """

    wm = pyinotify.WatchManager()
    paths: dict[str, dict[str | int, set["InotifyUpdater"]]] = dict()

    @staticmethod
    def init() -> None:
        notifier = pyinotify.ThreadedNotifier(
            InotifyUpdater.wm, InotifyUpdaterEventHandler()
        )
        notifier.start()

    # TODO Mask for folders
    MASK = pyinotify.IN_CREATE | pyinotify.IN_MODIFY | pyinotify.IN_DELETE

    def addPath(self, path: str, refresh: bool = True) -> None:
        path = os.path.realpath(os.path.expanduser(path))

        # Detect if file or folder
        if os.path.isdir(path):
            self.dirpath: str = path
            # 0: Directory watcher
            self.filename: str | int = 0
        elif os.path.isfile(path):
            self.dirpath = os.path.dirname(path)
            self.filename = os.path.basename(path)
        else:
            raise FileNotFoundError("No such file or directory: '{}'".format(path))

        # Register watch action
        if self.dirpath not in InotifyUpdater.paths:
            InotifyUpdater.paths[self.dirpath] = dict()
        if self.filename not in InotifyUpdater.paths[self.dirpath]:
            InotifyUpdater.paths[self.dirpath][self.filename] = set()
        InotifyUpdater.paths[self.dirpath][self.filename].add(self)

        # Add watch
        InotifyUpdater.wm.add_watch(self.dirpath, InotifyUpdater.MASK)

        if refresh:
            self.refreshData()


class ThreadedUpdaterThread(threading.Thread):
    def __init__(self, updater: "ThreadedUpdater") -> None:
        self.updater = updater
        threading.Thread.__init__(self, daemon=True)
        self.looping = True

    def run(self) -> None:
        try:
            while self.looping:
                self.updater.loop()
        except BaseException as e:
            log.error("Error with {}".format(self.updater))
            log.error(e, exc_info=True)
            self.updater.updateText("")


class ThreadedUpdater(Updater):
    """
    Must implement loop(), and call start()
    """

    def __init__(self) -> None:
        Updater.__init__(self)
        self.thread = ThreadedUpdaterThread(self)

    def loop(self) -> None:
        self.refreshData()
        time.sleep(10)

    def start(self) -> None:
        self.thread.start()


class I3Updater(ThreadedUpdater):
    # TODO OPTI One i3 connection for all

    def __init__(self) -> None:
        ThreadedUpdater.__init__(self)
        self.i3 = i3ipc.Connection()
        self.on = self.i3.on
        self.start()

    def loop(self) -> None:
        self.i3.main()


class MergedUpdater(Updater):
    def __init__(self, *args: Updater) -> None:
        raise NotImplementedError("Deprecated, as hacky and currently unused")