]> git.0d.be Git - django-panik-emissions.git/blob - emissions/models.py
cf4f5c492ed0155cf16dd2beb566e19a3cafe488
[django-panik-emissions.git] / emissions / models.py
1 import datetime
2 import os
3
4 from django.conf import settings
5 from django.core.exceptions import ObjectDoesNotExist
6 from django.forms import fields
7 from django.core.urlresolvers import reverse
8
9 from django.db import models
10 from django.utils.encoding import python_2_unicode_compatible
11 from django.utils.translation import ugettext
12 from django.utils.translation import ugettext_lazy as _
13
14 from django.db.models.signals import pre_save, post_delete
15 from django.dispatch.dispatcher import receiver
16
17 from ckeditor.fields import RichTextField
18 from taggit.managers import TaggableManager
19
20 from .utils import maybe_resize
21
22
23 LICENSES = (
24     ('', _('Unspecified')),
25     ('cc by', _('Creative Commons Attribution')),
26     ('cc by-sa', _('Creative Commons Attribution ShareAlike')),
27     ('cc by-nc', _('Creative Commons Attribution NonCommercial')),
28     ('cc by-nd', _('Creative Commons Attribution NoDerivs')),
29     ('cc by-nc-sa', _('Creative Commons Attribution NonCommercial ShareAlike')),
30     ('cc by-nc-nd', _('Creative Commons Attribution NonCommercial NoDerivs')),
31     ('cc0 / pd', _('Creative Commons Zero / Public Domain')),
32     ('artlibre', _('Art Libre')),
33 )
34
35 PODCAST_SOUND_QUALITY_LIST = (
36     ('standard', _('Standard')),
37     ('high', _('High')),
38     ('highest', _('Highest')),
39 )
40
41
42 class WeekdayMixin(object):
43     DAY_HOUR_START = 5
44
45     def get_weekday(self):
46         weekday = self.datetime.weekday() + 7
47         if self.datetime.time() < datetime.time(self.DAY_HOUR_START, 0):
48             weekday -= 1
49         weekday %= 7
50         return weekday
51
52     def is_on_weekday(self, day): # day is [1..7]
53         week_day = self.datetime.weekday()
54         if self.datetime.hour < self.DAY_HOUR_START:
55             week_day -= 1
56         week_day = (week_day % 7) + 1
57         return week_day == day
58
59
60 @python_2_unicode_compatible
61 class Category(models.Model):
62
63     class Meta:
64         verbose_name = _('Category')
65         verbose_name_plural = _('Categories')
66         ordering = ['title']
67
68     title = models.CharField(_('Title'), max_length=50)
69     slug = models.SlugField(null=True)
70     itunes_category = models.CharField(_('iTunes Category Name'), max_length=100, null=True)
71
72     def sorted_emission(self):
73         return self.emission_set.order_by('title')
74
75     def __str__(self):
76         return self.title
77
78
79 @python_2_unicode_compatible
80 class Colour(models.Model):
81
82     class Meta:
83         verbose_name = _('Colour')
84         verbose_name_plural = _('Colours')
85         ordering = ['title']
86
87     title = models.CharField(_('Title'), max_length=50)
88     slug = models.SlugField(null=True)
89
90     def sorted_emission(self):
91         return self.emission_set.order_by('title')
92
93     def __str__(self):
94         return self.title
95
96
97 @python_2_unicode_compatible
98 class Format(models.Model):
99
100     class Meta:
101         verbose_name = _('Format')
102         verbose_name_plural = _('Formats')
103         ordering = ['title']
104
105     title = models.CharField(_('Title'), max_length=50)
106     slug = models.SlugField(null=True)
107
108     def __str__(self):
109         return self.title
110
111
112 def get_emission_image_path(instance, filename):
113     return os.path.join('images', instance.slug,
114             os.path.basename(filename))
115
116
117 @python_2_unicode_compatible
118 class Emission(models.Model):
119
120     class Meta:
121         verbose_name = _('Emission')
122         verbose_name_plural = _('Emissions')
123         ordering = ['title']
124
125     title = models.CharField(_('Title'), max_length=200)
126     slug = models.SlugField(max_length=200)
127     subtitle = models.CharField(_('Subtitle'), max_length=80, null=True, blank=True)
128     text = RichTextField(_('Description'), null=True)
129     archived = models.BooleanField(_('Archived'), default=False)
130     categories = models.ManyToManyField(Category, verbose_name=_('Categories'), blank=True)
131     colours = models.ManyToManyField(Colour, verbose_name=_('Colours'), blank=True)
132
133     # XXX: languages (models.ManyToManyField(Language))
134
135     duration = models.IntegerField(_('Duration'), default=60,
136             help_text=_('In minutes'))
137
138     default_license = models.CharField(_('Default license for podcasts'),
139             max_length=20, blank=True, default='', choices=LICENSES)
140     podcast_sound_quality = models.CharField(_('Podcast sound quality'),
141             max_length=20, default='standard', choices=PODCAST_SOUND_QUALITY_LIST)
142     email = models.EmailField(_('Email'), max_length=254, null=True, blank=True)
143     website = models.URLField(_('Website'), null=True, blank=True)
144
145     image = models.ImageField(_('Image'),
146             upload_to=get_emission_image_path, max_length=250, null=True, blank=True)
147
148     chat_open = models.DateTimeField(null=True, blank=True)
149
150     # denormalized from Focus
151     got_focus = models.DateTimeField(default=None, null=True, blank=True)
152     has_focus = models.BooleanField(default=False)
153
154     creation_timestamp = models.DateTimeField(auto_now_add=True, null=True)
155     last_update_timestamp = models.DateTimeField(auto_now=True, null=True)
156
157     def get_absolute_url(self):
158         return reverse('emission-view', kwargs={'slug': str(self.slug)})
159
160     def __str__(self):
161         return self.title
162
163     def save(self, *args, **kwargs):
164         super(Emission, self).save(*args, **kwargs)
165         if self.id is not None and self.image:
166             maybe_resize(self.image.path)
167
168     def get_absolute_url(self):
169         return reverse('emission-view',
170                         kwargs={'slug':  str(self.slug)})
171
172     def get_schedules(self):
173         return Schedule.objects.filter(emission=self).order_by('datetime')
174
175     def get_sorted_episodes(self):
176         return self.episode_set.select_related().extra(select={
177                 'first_diffusion': 'emissions_diffusion.datetime',
178                 },
179                 select_params=(False, True),
180                 where=['''datetime = (SELECT MIN(datetime)
181                                         FROM emissions_diffusion
182                                        WHERE episode_id = emissions_episode.id)'''],
183                 tables=['emissions_diffusion'],
184             ).order_by('-first_diffusion')
185
186     def get_sorted_newsitems(self):
187         return self.newsitem_set.select_related().order_by('-date')
188
189     def get_next_planned_date_and_schedule(self, since=None):
190         schedules = self.schedule_set.filter(rerun=False)
191         if not schedules:
192             return None
193         if since is None:
194             since = datetime.datetime.today()
195         possible_dates = []
196         for schedule in schedules:
197             possible_dates.append((schedule.get_next_planned_date(since), schedule))
198         possible_dates.sort(key=lambda x: x[0])
199         return possible_dates[0]
200
201     def get_next_planned_date(self, since=None):
202         result = self.get_next_planned_date_and_schedule(since=since)
203         return result[0] if result else None
204
205     def get_next_planned_duration(self, since=None):
206         result = self.get_next_planned_date_and_schedule(since=since)
207         if not result:
208             return None
209         return result[1].duration or self.duration
210
211 @python_2_unicode_compatible
212 class Schedule(models.Model, WeekdayMixin):
213
214     class Meta:
215         verbose_name = _('Schedule')
216         verbose_name_plural = _('Schedules')
217         ordering = ['datetime']
218
219     WEEK_CHOICES = (
220         (0b1111, _('Every week')),
221         (0b0001, _('First week')),
222         (0b0010, _('Second week')),
223         (0b0100, _('Third week')),
224         (0b1000, _('Fourth week')),
225         (0b0101, _('First and third week')),
226         (0b1010, _('Second and fourth week'))
227     )
228     emission = models.ForeignKey('Emission', verbose_name=u'Emission')
229     datetime = models.DateTimeField()
230     weeks = models.IntegerField(_('Weeks'), default=15, choices=WEEK_CHOICES)
231     rerun = models.BooleanField(_('Rerun'), default=False)
232     duration = models.IntegerField(_('Duration'), null=True, blank=True,
233             help_text=_('In minutes'))
234
235     @property
236     def weeks_string(self):
237         if self.weeks == 0b0001:
238             return ugettext('1st of the month')
239         elif self.weeks == 0b0010:
240             return ugettext('2nd of the month')
241         elif self.weeks == 0b0100:
242             return ugettext('3rd of the month')
243         elif self.weeks == 0b1000:
244             return ugettext('4th of the month')
245         elif self.weeks == 0b0101:
246             return ugettext('1st and 3rd')
247         elif self.weeks == 0b1010:
248             return ugettext('2nd and 4th')
249         return None
250
251     def week_sort_key(self):
252         order = [
253             0b1111, # Every week
254             0b0001, # First week
255             0b0101, # First and third week
256             0b0010, # Second week
257             0b1010, # Second and fourth week
258             0b0100, # Third week
259             0b1000, # Fourth week
260         ]
261         if self.weeks in order:
262             return order.index(self.weeks)
263         return -1
264
265     def get_duration(self):
266         if self.duration:
267             return self.duration
268         else:
269             return self.emission.duration
270
271     def end_datetime(self):
272         return self.datetime + datetime.timedelta(minutes=self.get_duration())
273
274     def match_week(self, week_no):
275         if week_no == 4:
276             # this is the fifth week of the month, only return True for
277             # emissions scheduled every week.
278             return (self.weeks == 0b1111)
279         if (self.weeks & (0b0001<<(week_no)) == 0):
280             return False
281         return True
282
283     def matches(self, dt):
284         weekday = dt.weekday()
285         if dt.hour < self.DAY_HOUR_START:
286             weekday -= 1
287         if weekday != self.get_weekday():
288             return False
289         if self.weeks != 0b1111:
290             week_no = (dt.day-1) // 7
291             if self.match_week(week_no) is False:
292                 return False
293         if dt.time() >= self.datetime.time() and \
294                 dt.time() <= (self.datetime + datetime.timedelta(minutes=self.get_duration())).time():
295             return True
296         return False
297
298     def get_next_planned_date(self, since):
299         possible_dates = []
300         monday_since_date = since - datetime.timedelta(days=since.weekday())
301         start_week_date = self.datetime.replace(
302                 year=monday_since_date.year,
303                 month=monday_since_date.month,
304                 day=monday_since_date.day)
305         start_week_date -= datetime.timedelta(days=start_week_date.weekday())
306         start_week_date += datetime.timedelta(days=self.datetime.weekday())
307         for i in range(6):
308             week_date = start_week_date + datetime.timedelta(days=i*7)
309             if week_date < since:
310                 continue
311             if self.match_week((week_date.day-1)//7):
312                 possible_dates.append(week_date)
313         possible_dates.sort()
314         return possible_dates[0]
315
316
317     def __str__(self):
318         return u'%s at %s' % (self.emission.title,
319                 self.datetime.strftime('%a %H:%M'))
320
321
322 def get_episode_image_path(instance, filename):
323     return os.path.join('images', instance.emission.slug,
324             os.path.basename(filename))
325
326
327 @python_2_unicode_compatible
328 class Episode(models.Model):
329
330     class Meta:
331         verbose_name = _('Episode')
332         verbose_name_plural = _('Episodes')
333         ordering = ['title']
334
335     emission = models.ForeignKey('Emission', verbose_name=_('Emission'))
336     title = models.CharField(_('Title'), max_length=200)
337     slug = models.SlugField(max_length=200)
338     subtitle = models.CharField(_('Subtitle'), max_length=150, null=True, blank=True)
339     text = RichTextField(_('Description'), null=True)
340     tags = TaggableManager(_('Tags'), blank=True)
341     duration = models.IntegerField(_('Duration'), null=True, blank=True,
342             help_text=_('In minutes'))
343
344     image = models.ImageField(_('Image'),
345             upload_to=get_episode_image_path, max_length=250, null=True, blank=True)
346
347     effective_start = models.DateTimeField(null=True, blank=True)
348     effective_end = models.DateTimeField(null=True, blank=True)
349
350     # denormalized from Focus
351     got_focus = models.DateTimeField(default=None, null=True, blank=True)
352     has_focus = models.BooleanField(default=False)
353
354     creation_timestamp = models.DateTimeField(auto_now_add=True, null=True)
355     last_update_timestamp = models.DateTimeField(auto_now=True, null=True)
356
357     # XXX: languages (models.ManyToManyField(Language))
358
359     def __str__(self):
360         return self.title
361
362     def save(self, *args, **kwargs):
363         super(Episode, self).save(*args, **kwargs)
364         if self.id is not None and self.image:
365             maybe_resize(self.image.path)
366
367     def get_duration(self):
368         if self.duration:
369             return self.duration
370         else:
371             return self.emission.duration
372
373     def get_absolute_url(self):
374         return reverse('episode-view',
375                         kwargs={'emission_slug': str(self.emission.slug),
376                                 'slug':  str(self.slug)})
377
378     def has_sound(self):
379         return (self.soundfile_set.count() > 0)
380
381     def get_pige_download_url(self):
382         return '%s/%s-%s-%s.wav' % (
383                 settings.PIGE_DOWNLOAD_BASE_URL,
384                 self.effective_start.strftime('%Y%m%d'),
385                 self.effective_start.strftime('%Hh%Mm%S.%f'),
386                 self.effective_end.strftime('%Hh%Mm%S.%f'))
387
388     _soundfiles = {}
389
390     @classmethod
391     def set_prefetched_soundfiles(cls, soundfiles):
392         cls._soundfiles.update(soundfiles)
393
394     def has_prefetched_soundfile(self):
395         return self.id in self._soundfiles
396
397     def get_prefetched_soundfile(self):
398         return self._soundfiles.get(self.id)
399
400     _main_sound = False
401
402     @property
403     def main_sound(self):
404         if self._main_sound is not False:
405             return self._main_sound
406
407         if self.has_prefetched_soundfile():
408             self._main_sound = self.get_prefetched_soundfile()
409             return self._main_sound
410
411         t = self.soundfile_set.exclude(podcastable=False).exclude(fragment=True)
412         if t:
413             self._main_sound = t[0]
414         else:
415             self._main_sound = None
416
417         return self._main_sound
418
419     @main_sound.setter
420     def main_sound(self, value):
421         self._main_sound = value
422
423     def fragment_sounds(self):
424         return self.soundfile_set.exclude(podcastable=False).exclude(fragment=False)
425
426     def diffusions(self):
427         return Diffusion.objects.filter(episode=self.id).order_by('datetime')
428
429
430 @python_2_unicode_compatible
431 class Diffusion(models.Model, WeekdayMixin):
432
433     class Meta:
434         verbose_name = _('Diffusion')
435         verbose_name_plural = _('Diffusions')
436         ordering = ['datetime']
437
438     episode = models.ForeignKey('Episode', verbose_name=_('Episode'))
439     datetime = models.DateTimeField(_('Date/time'), db_index=True)
440
441     def __str__(self):
442         return u'%s at %02d:%02d' % (self.episode.title, self.datetime.hour,
443                 self.datetime.minute)
444
445     def get_duration(self):
446         return self.episode.get_duration()
447
448     def end_datetime(self):
449         return self.datetime + datetime.timedelta(minutes=self.get_duration())
450
451
452 @python_2_unicode_compatible
453 class Absence(models.Model):
454
455     class Meta:
456         verbose_name = _('Absence')
457         verbose_name_plural = _('Absences')
458
459     emission = models.ForeignKey('Emission', verbose_name=u'Emission')
460     datetime = models.DateTimeField(_('Date/time'), db_index=True)
461
462     def __str__(self):
463         return u'Absence for %s on %s' % (self.emission.title, self.datetime)
464
465
466 def get_sound_path(instance, filename):
467     return os.path.join('sounds.orig', instance.episode.emission.slug,
468             os.path.basename(filename))
469
470
471 @python_2_unicode_compatible
472 class SoundFile(models.Model):
473
474     class Meta:
475         verbose_name = _('Sound file')
476         verbose_name_plural = _('Sound files')
477         ordering = ['creation_timestamp']
478
479     episode = models.ForeignKey('Episode', verbose_name=_('Episode'))
480     file = models.FileField(_('File'), upload_to=get_sound_path, max_length=250)
481     podcastable = models.BooleanField(_('Podcastable'), default=False,
482             db_index=True,
483             help_text=_('The file can be published online according to SABAM rules.'))
484     fragment = models.BooleanField(_('Fragment'), default=False, db_index=True,
485             help_text=_('The file is some segment or extra content, not the complete recording.'))
486     title = models.CharField(_('Title'), max_length=200)
487     duration = models.IntegerField(_('Duration'), null=True, help_text=_('In seconds'))
488
489     format = models.ForeignKey('Format', verbose_name=_('Format'), null=True, blank=True)
490     license = models.CharField(_('License'), max_length=20, blank=True, default='', choices=LICENSES)
491
492     # denormalized from Focus
493     got_focus = models.DateTimeField(default=None, null=True, blank=True)
494     has_focus = models.BooleanField(default=False)
495
496     creation_timestamp = models.DateTimeField(auto_now_add=True, null=True)
497     last_update_timestamp = models.DateTimeField(auto_now=True, null=True)
498
499     def get_format_filename(self, format):
500         return '%s_%05d__%s.%s' % (
501                 self.episode.slug,
502                 self.id,
503                 (self.fragment and '0' or '1'),
504                 format)
505
506     def get_format_path(self, format):
507         if not self.file:
508             return None
509         return '%s/%s' % (os.path.dirname(self.file.path).replace('.orig', ''), self.get_format_filename(format))
510
511     def get_format_url(self, format):
512         if not self.file:
513             return None
514         return '%s/%s' % (os.path.dirname(self.file.url).replace('.orig', ''), self.get_format_filename(format))
515
516     def get_duration_string(self):
517         if not self.duration:
518             return ''
519         return '%d:%02d' % (self.duration/60, self.duration%60)
520
521     def __str__(self):
522         return '%s - %s' % (self.title or self.id, self.episode.title)
523
524
525 @python_2_unicode_compatible
526 class NewsCategory(models.Model):
527
528     class Meta:
529         verbose_name = _('News Category')
530         verbose_name_plural = _('News Categories')
531         ordering = ['title']
532
533     title = models.CharField(_('Title'), max_length=50)
534     slug = models.SlugField(null=True)
535
536     def __str__(self):
537         return self.title
538
539     def get_sorted_newsitems(self):
540         return self.newsitem_set.select_related().order_by('-date')
541
542
543 def get_newsitem_image_path(instance, filename):
544     return os.path.join('images', 'news', instance.slug,
545             os.path.basename(filename))
546
547
548 @python_2_unicode_compatible
549 class NewsItem(models.Model):
550
551     class Meta:
552         verbose_name = _('News Item')
553         verbose_name_plural = _('News Items')
554         ordering = ['title']
555
556     title = models.CharField(_('Title'), max_length=200)
557     slug = models.SlugField(max_length=200)
558     text = RichTextField(_('Description'))
559     date = models.DateField(_('Publication Date'),
560             help_text=_('The news won\'t appear on the website before this date.'))
561     image = models.ImageField(_('Image'),
562             upload_to=get_newsitem_image_path, max_length=250, null=True, blank=True)
563
564     tags = TaggableManager(_('Tags'), blank=True)
565     category = models.ForeignKey('NewsCategory', verbose_name=_('Category'), null=True, blank=True)
566     emission = models.ForeignKey('Emission', verbose_name=_('Emission'), null=True, blank=True)
567
568     expiration_date = models.DateField(_('Expiration Date'), null=True, blank=True)
569     event_date = models.DateField(_('Event Date'), null=True, blank=True,
570             help_text=_('If this is an event, set the date here so it appears in the agenda.'))
571
572     # denormalized from Focus
573     got_focus = models.DateTimeField(default=None, null=True, blank=True)
574     has_focus = models.BooleanField(default=False)
575
576     creation_timestamp = models.DateTimeField(auto_now_add=True, null=True)
577     last_update_timestamp = models.DateTimeField(auto_now=True, null=True)
578
579     def __str__(self):
580         return self.title
581
582     def get_absolute_url(self):
583         return reverse('newsitem-view', kwargs={'slug': str(self.slug)})
584
585
586 @python_2_unicode_compatible
587 class Nonstop(models.Model):
588
589     class Meta:
590         verbose_name = _('Nonstop zone')
591         verbose_name_plural = _('Nonstop zones')
592         ordering = ['title']
593
594     title = models.CharField(_('Title'), max_length=50)
595     slug = models.SlugField()
596
597     start = models.TimeField(_('Start'))
598     end = models.TimeField(_('End'))
599     text = RichTextField(_('Description'), null=True, blank=True)
600     redirect_path = models.CharField(_('Redirect Path'), max_length=200, blank=True)
601
602     def __str__(self):
603         return self.title
604
605
606 @python_2_unicode_compatible
607 class Focus(models.Model):
608     title = models.CharField(_('Alternate Title'), max_length=50,
609             null=True, blank=True)
610     newsitem = models.ForeignKey('NewsItem', verbose_name=_('News Item'),
611             null=True, blank=True)
612     emission = models.ForeignKey('Emission', verbose_name=_('Emission'),
613             null=True, blank=True)
614     episode = models.ForeignKey('Episode', verbose_name=_('Episode'),
615             null=True, blank=True)
616     soundfile = models.ForeignKey('SoundFile', verbose_name=_('Sound file'),
617             null=True, blank=True)
618     page = models.ForeignKey('data.Page', verbose_name=_('Page'),
619             null=True, blank=True)
620     current = models.BooleanField('Current', default=True)
621
622     creation_timestamp = models.DateTimeField(auto_now_add=True, null=True)
623     last_update_timestamp = models.DateTimeField(auto_now=True, null=True)
624
625     def __str__(self):
626         if self.newsitem:
627             return u'Newsitem: %s' % self.newsitem.title
628         if self.emission:
629             return u'Emission: %s' % self.emission.title
630         if self.episode:
631             return u'Episode: %s' % self.episode.title
632         if self.soundfile:
633             return u'Soundfile: %s' % (self.soundfile.title or self.soundfile.episode.title)
634         if self.page:
635             return u'Page: %s' % self.page.title
636         return u'%s' % self.id
637
638     def focus_title(self):
639         if self.title:
640             return self.title
641         if self.newsitem:
642             return self.newsitem.title
643         if self.emission:
644             return self.emission.title
645         if self.page:
646             return self.page.title
647
648         episode = None
649         if self.soundfile:
650             if self.soundfile.fragment and self.soundfile.title:
651                 return self.soundfile.title
652             episode = self.soundfile.episode
653         elif self.episode:
654             episode = self.episode
655
656         if episode:
657             if episode.title:
658                 return episode.title
659             else:
660                 return episode.emission.title
661
662         return None
663
664     def content_image(self):
665         if self.newsitem:
666             return self.newsitem.image
667         if self.emission:
668             return self.emission.image
669         if self.page:
670             from panikombo.models import Topik
671             return Topik.objects.get(page=self.page).image
672
673         episode = None
674         if self.soundfile:
675             episode = self.soundfile.episode
676         elif self.episode:
677             episode = self.episode
678
679         if episode:
680             if episode.image:
681                 return episode.image
682             else:
683                 return episode.emission.image
684
685     def content_category_title(self):
686         if self.newsitem:
687             if self.newsitem.category:
688                 return self.newsitem.category.title
689             return _('News')
690         if self.emission:
691             return _('Emission')
692         if self.episode:
693             return self.episode.emission.title
694         if self.soundfile:
695             return self.soundfile.episode.emission.title
696         if self.page:
697             return 'Topik'
698
699     def get_related_object(self):
700         try:
701             if self.newsitem:
702                 return self.newsitem
703             if self.emission:
704                 return self.emission
705             if self.episode:
706                 return self.episode
707             if self.soundfile:
708                 return self.soundfile
709             if self.page:
710                 from panikombo.models import Topik
711                 return Topik.objects.get(page=self.page)
712         except ObjectDoesNotExist:
713             return None
714
715         return None
716
717
718 def get_playlist_sound_path(instance, filename):
719     return os.path.join('playlists', instance.episode.emission.slug,
720             instance.episode.slug, os.path.basename(filename))
721
722
723 class PlaylistElement(models.Model):
724     episode = models.ForeignKey('Episode', null=True)
725     title = models.CharField(_('Title'), max_length=200)
726     notes = models.CharField(_('Notes'), max_length=200, blank=True, default='')
727     sound = models.FileField(_('Sound'), upload_to=get_playlist_sound_path, max_length=250)
728     order = models.PositiveIntegerField()
729
730     class Meta:
731         verbose_name = _('Playlist Element')
732         verbose_name_plural = _('Playlist Elements')
733         ordering = ['order']
734
735     def shortcut(self):
736         return chr(ord('a')+self.order-1)
737
738
739 @receiver(pre_save, sender=Focus, dispatch_uid='focus_pre_save')
740 def set_focus_on_save(sender, instance, **kwargs):
741     object = instance.get_related_object()
742     must_save = False
743     if instance.current != object.has_focus:
744         object.has_focus = instance.current
745         must_save = True
746     if object and not object.got_focus and instance.current:
747         object.got_focus = datetime.datetime.now()
748         must_save = True
749     if must_save:
750         object.save()
751
752 @receiver(post_delete, sender=Focus, dispatch_uid='focus_post_delete')
753 def remove_focus_on_delete(sender, instance, **kwargs):
754     object = instance.get_related_object()
755     if object and (object.got_focus or object.has_focus):
756         object.got_focus = None
757         object.has_focus = False
758         object.save()