rework the model structure to avoide migration errors

README.rst

@@ -116,6 +116,7 @@ Same as Wagtail Images, a custom model can be used to replace the built in Video
 
     # app.videos.models
     from django.db import models
+    from modelcluster.fields import ParentalKey
     from wagtailvideos.models import AbstractVideo, AbstractVideoTranscode
 
     class AttributedVideo(AbstractVideo):
@@ -137,6 +138,13 @@ Same as Wagtail Images, a custom model can be used to replace the built in Video
             unique_together = (
                 ('video', 'media_format')
             )
+        
+    # Only needed if you are using the text tracks feature
+    class CustomTrackListing(AbstractTrackListing):
+        video = models.OneToOneField(AttributedVideo, related_name='track_listing', on_delete=models.CASCADE)
+
+    class CustomVideoTrack(AbstractVideoTrack):
+        listing = ParentalKey(CustomTrackListing, related_name='tracks', on_delete=models.CASCADE)
 
 
 Video text tracks:

tests/app/models.py

 from django.db import models
-from wagtail.core.models import Page
-from wagtail.core.fields import StreamField
+from modelcluster.fields import ParentalKey
 from wagtail.admin.edit_handlers import StreamFieldPanel
+from wagtail.core.fields import StreamField
+from wagtail.core.models import Page
 
-from wagtailvideos.edit_handlers import VideoChooserPanel
 from wagtailvideos.blocks import VideoChooserBlock
-from wagtailvideos.models import AbstractVideo, AbstractVideoTranscode
-from modelcluster.fields import ParentalKey
+from wagtailvideos.edit_handlers import VideoChooserPanel
+from wagtailvideos.models import (
+    AbstractTrackListing, AbstractVideo, AbstractVideoTrack,
+    AbstractVideoTranscode)
 
 
 class CustomVideoModel(AbstractVideo):
@@ -31,6 +33,14 @@ class CustomVideoTranscode(AbstractVideoTranscode):
         )
 
 
+class CustomTrackListing(AbstractTrackListing):
+    video = models.OneToOneField(CustomVideoModel, related_name='track_listing', on_delete=models.CASCADE)
+
+
+class CustomVideoTrack(AbstractVideoTrack):
+    listing = ParentalKey(CustomTrackListing, related_name='tracks', on_delete=models.CASCADE)
+
+
 class TestPage(Page):
     video_field = models.ForeignKey(
         CustomVideoModel, related_name='+', null=True, blank=True, on_delete=models.SET_NULL)

tests/app/settings.py

@@ -16,7 +16,7 @@ INSTALLED_APPS = [
     'wagtail.snippets',
     'wagtail.images',
     'wagtail.documents',
-    'wagtail.contrib.modeladmin',
+    # 'wagtail.contrib.modeladmin',
 
     'django.contrib.admin',
     'django.contrib.auth',

wagtailvideos/models.py

@@ -15,6 +15,7 @@ from django.core.exceptions import SuspiciousFileOperation
 from django.core.files.base import ContentFile
 from django.db import models
 from django.forms.utils import flatatt
+from django.apps import apps
 from django.urls import reverse
 from django.utils.safestring import mark_safe
 from django.utils.translation import ugettext_lazy as _
@@ -179,6 +180,10 @@ class AbstractVideo(CollectionMember, index.Indexed, models.Model):
     def get_transcode_model(cls):
         return cls.transcodes.rel.related_model
 
+    @classmethod
+    def get_track_listing_model(cls):
+        return cls.track_listing.related.related_model
+
     def video_tag(self, attrs=None):
         if attrs is None:
             attrs = {}
@@ -222,7 +227,6 @@ class AbstractVideo(CollectionMember, index.Indexed, models.Model):
 
     class Meta:
         abstract = True
-        ordering = ['-created_at']
 
 
 class Video(AbstractVideo):
@@ -234,6 +238,9 @@ class Video(AbstractVideo):
         'tags',
     )
 
+    class Meta:
+        ordering = ['-created_at']
+
 
 class TranscodingThread(threading.Thread):
     def __init__(self, transcode, **kwargs):
@@ -319,17 +326,25 @@ class VideoTranscode(AbstractVideoTranscode):
         )
 
 
-class TrackListing(ClusterableModel):
-    video = models.OneToOneField(
-        get_video_model_string(), on_delete=models.CASCADE,
-        related_name='track_listing')
-
+class AbstractTrackListing(ClusterableModel):
     def __str__(self):
         return self.video.title
 
+    @classmethod
+    def get_track_model(cls):
+        return cls.tracks.rel.related_model
 
-class VideoTrack(Orderable):
-    listing = ParentalKey(TrackListing, related_name='tracks', on_delete=models.CASCADE)
+    class Meta:
+        abstract = True
+
+
+class TrackListing(AbstractTrackListing):
+    video = models.OneToOneField(
+        Video, on_delete=models.CASCADE,
+        related_name='track_listing')
+
+
+class AbstractVideoTrack(Orderable):
     # TODO move to TextChoices once django < 3 is dropped
     track_kinds = [
         ('subtitles', 'Subtitles'),
@@ -375,3 +390,10 @@ class VideoTrack(Orderable):
         folder_name = 'video_tracks'
         filename = self.file.field.storage.get_valid_name(filename)
         return os.path.join(folder_name, filename)
+
+    class Meta:
+        abstract = True
+
+
+class VideoTrack(AbstractVideoTrack):
+    listing = ParentalKey(TrackListing, related_name='tracks', on_delete=models.CASCADE)

wagtailvideos/signals.py

@@ -6,7 +6,6 @@ from django.db import transaction
 from django.db.models.signals import post_delete, post_save
 
 from wagtailvideos import ffmpeg, get_video_model
-from wagtailvideos.models import VideoTrack
 
 
 @contextmanager
@@ -68,6 +67,8 @@ def video_post_save(instance, **kwargs):
 def register_signal_handlers():
     Video = get_video_model()
     VideoTranscode = Video.get_transcode_model()
+    TrackListing = Video.get_track_listing_model()
+    VideoTrack = TrackListing.get_track_model()
 
     post_save.connect(video_post_save, sender=Video)
     post_delete.connect(post_delete_file_cleanup, sender=Video)

wagtailvideos/views/videos.py

@@ -16,7 +16,6 @@ from wagtail.search.backends import get_search_backends
 from wagtailvideos import ffmpeg, get_video_model, is_modeladmin_installed
 from wagtailvideos.forms import VideoTranscodeAdminForm, get_video_form
 from wagtailvideos.permissions import permission_policy
-from wagtailvideos.models import TrackListing
 
 if LooseVersion(wagtail.__version__) >= LooseVersion('2.7'):
     from wagtail.admin.auth import PermissionPolicyChecker
@@ -72,7 +71,6 @@ def index(request):
             'videos': page,
             'query_string': query_string,
             'is_searching': bool(query_string),
-
             'search_form': form,
             'popular_tags': popular_tags_for_model(Video),
             'current_collection': current_collection,
@@ -120,7 +118,7 @@ def edit(request, video_id):
             messages.button(reverse('wagtailvideos:delete', args=(video.id,)), _('Delete'))
         ])
     if is_modeladmin_installed():
-        url_helper = AdminURLHelper(TrackListing)
+        url_helper = AdminURLHelper(Video.get_track_listing_model())
         if hasattr(video, 'track_listing'):
             action_url = url_helper.get_action_url('edit', instance_pk=video.track_listing.pk)
         else:

wagtailvideos/wagtail_hooks.py

@@ -22,7 +22,7 @@ Video = get_video_model()
 
 
 class TracksAdmin(ModelAdmin):
-    model = TrackListing
+    model = Video.get_track_listing_model()
     menu_icon = 'openquote'
     menu_label = 'Text tracks'