from django.apps import apps
from simple_history.models import HistoricalRecords, registered_models


class ProxyAwareHistoricalRecords(HistoricalRecords):
    # inspired by https://github.com/jazzband/django-simple-history/issues/544
    def _find_base_history(self, opts):
        base_history = None
        for parent_class in opts.parents.keys():
            if hasattr(parent_class, 'history'):
                base_history = parent_class.history.model
        return base_history

    def create_history_model(self, model, inherited):
        opts = model._meta
        if opts.proxy:
            base_history = self._find_base_history(opts)
            if base_history:
                return self.create_proxy_history_model(model, inherited, base_history)

        return super().create_history_model(model, inherited)

    def create_proxy_history_model(self, model, inherited, base_history):
        opts = model._meta
        attrs = {
            '__module__': self.module,
            '_history_excluded_fields': self.excluded_fields,
        }
        app_module = f'{opts.app_label}.models'
        if inherited:
            attrs['__module__'] = model.__module__
        elif model.__module__ != self.module:
            # registered under different app
            attrs['__module__'] = self.module
        elif app_module != self.module:
            # Abuse an internal API because the app registry is loading.
            app = apps.app_configs[opts.app_label]
            models_module = app.name
            attrs['__module__'] = models_module

        attrs.update(
            Meta=type(
                'Meta',
                (),
                {**self.get_meta_options(model), 'proxy': True}
            )
        )
        if self.table_name is not None:
            attrs['Meta'].db_table = self.table_name

        name = self.get_history_model_name(model)
        registered_models[opts.db_table] = model
        return type(str(name), (base_history,), attrs)