Automatically register multiple Wagtail tag models

models.py

"""Wagtail models."""

from django.db.models import CASCADE, Model
from modelcluster.contrib.taggit import ClusterTaggableManager
from taggit.models import TaggedItemBase
from wagtail.models import Page, ParentalKey


TAG_FIELDS = [
    ("Tag Category 1", "tag_category_1"),
    ("Tag Category 2", "tag_category_2"),
    ("Tag Category 3", "tag_category_3"),
]


def register_tag_fields(cls: Model):
    """Register tag fields for model."""

    def _model_wrapper(cls: Model):
        """Model wrapper."""
        for verbose_name, field in dict(TAG_FIELDS).items():
            meta_model_fields = {"app_label": cls._meta.app_label}
            meta_model = type("Meta", (), meta_model_fields)
            tag_model_related_name = (
                f"tagged_{cls._meta.model_name.lower()}_{field}_items"
            )
            tag_model_fields = {
                "Meta": meta_model,
                "__module__": cls.__module__,
                "content_object": ParentalKey(
                    f"{cls._meta.app_label}.{cls._meta.model_name}",
                    on_delete=CASCADE,
                    related_name=tag_model_related_name,
                ),
            }
            tag_model_suffix = "".join(word.capitalize() or "_" for word in f"{field}Tag".split("_"))
            tag_model_name = f"{cls._meta.object_name}{tag_model_suffix}"
            tag_model = type(tag_model_name, (TaggedItemBase,), tag_model_fields)
            instance_related_name = f"related_{cls._meta.model_name.lower()}_{field}"
            instance = ClusterTaggableManager(
                through=tag_model,
                blank=True,
                verbose_name=verbose_name,
                related_name=instance_related_name,
            )
            instance.contribute_to_class(cls, field)
        return cls

    return _model_wrapper(cls)


@register_tag_fields
class CustomPage(Page):
    """Custom page."""

    promote_panels = Page.promote_panels + [
        FieldPanel("tag_category_1"),
        FieldPanel("tag_category_2"),
        FieldPanel("tag_category_3"),
    ]