PlexKodiConnect/resources/lib/playlists/common.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
from __future__ import absolute_import, division, unicode_literals
from future import standard_library
standard_library.install_aliases()
from builtins import object
from logging import getLogger
import queue
import time
import os
import hashlib

from ..watchdog import events
from ..watchdog.observers import Observer
from ..watchdog.utils.bricks import OrderedSetQueue

from .. import path_ops, variables as v, app
###############################################################################
LOG = getLogger('PLEX.playlists.common')

# These filesystem events are considered similar
SIMILAR_EVENTS = (events.EVENT_TYPE_CREATED, events.EVENT_TYPE_MODIFIED)
###############################################################################


class PlaylistError(Exception):
    """
    The one main exception thrown if anything goes awry
    """
    pass


class Playlist(object):
    """
    Class representing a synced Playlist with info for both Kodi and Plex.
    Attributes:
    Plex:
        plex_id: unicode
        plex_name: unicode
        plex_updatedat: unicode

    Kodi:
        kodi_path: unicode
        kodi_filename: unicode
        kodi_extension: unicode
        kodi_type: unicode
        kodi_hash: unicode

    Testing for a Playlist() returns ONLY True if all the following attributes
    are set; 2 playlists are only equal if all attributes are equal:
        plex_id
        plex_name
        plex_updatedat
        kodi_path
        kodi_filename
        kodi_type
        kodi_hash
    """
    def __init__(self):
        # Plex
        self.plex_id = None
        self.plex_name = None
        self.plex_updatedat = None
        # Kodi
        self._kodi_path = None
        self.kodi_filename = None
        self.kodi_extension = None
        self.kodi_type = None
        self.kodi_hash = None

    def __unicode__(self):
        return ("{{"
                "'plex_id': {self.plex_id}, "
                "'plex_name': '{self.plex_name}', "
                "'kodi_type': '{self.kodi_type}', "
                "'kodi_filename': '{self.kodi_filename}', "
                "'kodi_path': '{self._kodi_path}', "
                "'plex_updatedat': {self.plex_updatedat}, "
                "'kodi_hash': '{self.kodi_hash}'"
                "}}").format(self=self)

    def __repr__(self):
        return self.__unicode__().encode('utf-8')

    def __str__(self):
        return self.__repr__()

    def __bool__(self):
        return (self.plex_id and self.plex_updatedat and self.plex_name and
                self._kodi_path and self.kodi_filename and self.kodi_type and
                self.kodi_hash)

    # Used for comparison of playlists
    @property
    def key(self):
        return (self.plex_id, self.plex_updatedat, self.plex_name,
                self._kodi_path, self.kodi_filename, self.kodi_type,
                self.kodi_hash)

    def __eq__(self, playlist):
        return self.key == playlist.key

    def __ne__(self, playlist):
        return self.key != playlist.key

    @property
    def kodi_path(self):
        return self._kodi_path

    @kodi_path.setter
    def kodi_path(self, path):
        f = path_ops.path.basename(path)
        try:
            self.kodi_filename, self.kodi_extension = f.rsplit('.', 1)
        except ValueError:
            LOG.error('Trying to set invalid path: %s', path)
            raise PlaylistError('Invalid path: %s' % path)
        if path.startswith(v.PLAYLIST_PATH_VIDEO):
            self.kodi_type = v.KODI_TYPE_VIDEO_PLAYLIST
        elif path.startswith(v.PLAYLIST_PATH_MUSIC):
            self.kodi_type = v.KODI_TYPE_AUDIO_PLAYLIST
        else:
            LOG.error('Playlist type not supported for %s', path)
            raise PlaylistError('Playlist type not supported: %s' % path)
        if not self.plex_name:
            self.plex_name = self.kodi_filename
        self._kodi_path = path


def kodi_playlist_hash(path):
    """
    Returns a md5 hash [unicode] using os.stat() st_size and st_mtime for the
    playlist located at path [unicode]
    (size of file in bytes and time of most recent content modification)

    There are probably way more efficient ways out there to do this
    """
    stat = os.stat(path_ops.encode_path(path))
    # stat.st_size is of type long; stat.st_mtime is of type float - hash both
    m = hashlib.md5()
    m.update(repr(stat.st_size))
    m.update(repr(stat.st_mtime))
    return m.hexdigest().decode('utf-8')


class PlaylistQueue(OrderedSetQueue):
    """
    OrderedSetQueue that drops all directory events immediately
    """
    def _put(self, item):
        if item[0].is_directory:
            self.unfinished_tasks -= 1
        else:
            # Can't use super as OrderedSetQueue is old style class
            OrderedSetQueue._put(self, item)


class PlaylistObserver(Observer):
    """
    PKC implementation, overriding the dispatcher. PKC will wait for the
    duration timeout (in seconds) AFTER receiving a filesystem event. A new
    ("non-similar") event will reset the timer.
    Creating and modifying will be regarded as equal.
    """
    def __init__(self, *args, **kwargs):
        super(PlaylistObserver, self).__init__(*args, **kwargs)
        # Drop the same events that get into the queue even if there are other
        # events in between these similar events. Ignore directory events
        # completely
        self._event_queue = PlaylistQueue()

    @staticmethod
    def _pkc_similar_events(event1, event2):
        if event1 == event2:
            return True
        elif (event1.src_path == event2.src_path and
              event1.event_type in SIMILAR_EVENTS and
              event2.event_type in SIMILAR_EVENTS):
            # Set created and modified events to equal
            return True
        return False

    def _dispatch_iterator(self, event_queue, timeout):
        """
        This iterator will block for timeout (seconds) until an event is
        received or raise Queue.Empty.
        """
        event, watch = event_queue.get(block=True, timeout=timeout)
        event_queue.task_done()
        start = time.time()
        while time.time() - start < timeout:
            try:
                new_event, new_watch = event_queue.get(block=False)
            except queue.Empty:
                app.APP.monitor.waitForAbort(0.2)
            else:
                event_queue.task_done()
                start = time.time()
                if self._pkc_similar_events(new_event, event):
                    continue
                else:
                    yield event, watch
                    event, watch = new_event, new_watch
        yield event, watch

    def dispatch_events(self, event_queue, timeout):
        for event, watch in self._dispatch_iterator(event_queue, timeout):
            # This is copy-paste of original code
            with self._lock:
                # To allow unschedule/stop and safe removal of event handlers
                # within event handlers itself, check if the handler is still
                # registered after every dispatch.
                for handler in list(self._handlers.get(watch, [])):
                    if handler in self._handlers.get(watch, []):
                        handler.dispatch(event)