[migration] Support choose collection

wagtailvideos/migrations/0013_add_choose_permissions.py

+# Generated by Django 3.1.2 on 2022-10-03 22:43
+
+from django.db import migrations
+
+
+def add_choose_permission_to_admin_groups(apps, _schema_editor):
+    ContentType = apps.get_model("contenttypes.ContentType")
+    Permission = apps.get_model("auth.Permission")
+    Group = apps.get_model("auth.Group")
+
+    # Get video content type
+    video_content_type, _created = ContentType.objects.get_or_create(
+        model="video", app_label="wagtailvideos"
+    )
+
+    # Create the Choose permission (if it doesn't already exist)
+    choose_video_permission, _created = Permission.objects.get_or_create(
+        content_type=video_content_type,
+        codename="choose_video",
+        defaults={"name": "Can choose video"},
+    )
+
+    # Assign it to all groups which have "Access the Wagtail admin" permission.
+    # This emulates the previous behaviour, where everyone could choose any video in any Collection
+    # because choosing wasn't permissioned.
+    for group in Group.objects.filter(permissions__codename="access_admin"):
+        group.permissions.add(choose_video_permission)
+
+
+def remove_choose_permission(apps, _schema_editor):
+    """Reverse the above additions of permissions."""
+    ContentType = apps.get_model("contenttypes.ContentType")
+    Permission = apps.get_model("auth.Permission")
+    video_content_type = ContentType.objects.get(
+        model="video",
+        app_label="wagtailvideos",
+    )
+    # This cascades to Group
+    Permission.objects.filter(
+        content_type=video_content_type, codename="choose_video"
+    ).delete()
+
+
+def get_choose_permission(apps):
+    Permission = apps.get_model("auth.Permission")
+    ContentType = apps.get_model("contenttypes.ContentType")
+
+    video_content_type, _created = ContentType.objects.get_or_create(
+        model="video",
+        app_label="wagtailvideos",
+    )
+    return Permission.objects.filter(
+        content_type=video_content_type, codename__in=["choose_video"]
+    ).first()
+
+
+def copy_choose_permission_to_collections(apps, _schema_editor):
+    Collection = apps.get_model("wagtailcore.Collection")
+    Group = apps.get_model("auth.Group")
+    GroupCollectionPermission = apps.get_model("wagtailcore.GroupCollectionPermission")
+
+    root_collection = Collection.objects.get(depth=1)
+
+    permission = get_choose_permission(apps)
+    if permission:
+        for group in Group.objects.filter(permissions=permission):
+            GroupCollectionPermission.objects.create(
+                group=group, collection=root_collection, permission=permission
+            )
+
+
+def remove_choose_permission_from_collections(apps, _schema_editor):
+    GroupCollectionPermission = apps.get_model("wagtailcore.GroupCollectionPermission")
+    choose_permission = get_choose_permission(apps)
+    if choose_permission:
+        GroupCollectionPermission.objects.filter(permission=choose_permission).delete()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("wagtailvideos", "0012_remove_unique_constraint"),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name="video",
+            options={
+                "permissions": [("choose_video", "Can choose video")],
+                "verbose_name": "video",
+                "verbose_name_plural": "videos",
+            },
+        ),
+        migrations.RunPython(
+            add_choose_permission_to_admin_groups, remove_choose_permission
+        ),
+        migrations.RunPython(
+            copy_choose_permission_to_collections,
+            remove_choose_permission_from_collections,
+        ),
+    ]