[Refactor] Move OfferWizardStepView to separate file (#4174)

* refactor :package: move OfferWizardStepView to separate file

* refactor :package: remove unused offer combinations code

* refactor :package: remove unused get_back_url method

src/oscar/apps/dashboard/offers/views.py

@@ -1,16 +1,12 @@
-import json
-
 from django.conf import settings
 from django.contrib import messages
-from django.core import serializers
-from django.core.serializers.json import DjangoJSONEncoder
 from django.db.models import Count, Q
 from django.http import HttpResponseRedirect
 from django.shortcuts import get_object_or_404, redirect
 from django.urls import reverse
 from django.utils import timezone
 from django.utils.translation import gettext_lazy as _
-from django.views.generic import DeleteView, FormView, ListView
+from django.views.generic import DeleteView, ListView
 
 from oscar.core.loading import get_class, get_classes, get_model
 from oscar.views import sort_queryset
@@ -37,6 +33,7 @@ Benefit = get_model("offer", "Benefit")
         "OfferSearchForm",
     ],
 )
+OfferWizardStepView = get_class("dashboard.offers.wizard_views", "OfferWizardStepView")
 OrderDiscountCSVFormatter = get_class(
     "dashboard.offers.reports", "OrderDiscountCSVFormatter"
 )
@@ -125,197 +122,6 @@ class OfferListView(ListView):
         return ctx
 
 
-class OfferWizardStepView(FormView):
-    wizard_name = "offer_wizard"
-    form_class = None
-    step_name = None
-    update = False
-    url_name = None
-    success_url_name = "dashboard:offer-list"
-
-    # Keep a reference to previous view class to allow checks to be made on
-    # whether prior steps have been completed
-    previous_view = None
-
-    # pylint: disable=attribute-defined-outside-init
-    def dispatch(self, request, *args, **kwargs):
-        if self.update:
-            self.offer = get_object_or_404(ConditionalOffer, id=kwargs["pk"])
-        if not self.is_previous_step_complete(request):
-            messages.warning(
-                request,
-                _("%s step not complete") % (self.previous_view.step_name.title(),),
-            )
-            return HttpResponseRedirect(self.get_back_url())
-        return super().dispatch(request, *args, **kwargs)
-
-    def is_previous_step_complete(self, request):
-        if not self.previous_view:
-            return True
-        return self.previous_view.is_valid(self, request)
-
-    def _key(self, step_name=None, is_object=False):
-        key = step_name if step_name else self.step_name
-        if self.update:
-            key += str(self.offer.id)
-        if is_object:
-            key += "_obj"
-        return key
-
-    def _store_form_kwargs(self, form):
-        session_data = self.request.session.setdefault(self.wizard_name, {})
-
-        # Adjust kwargs to avoid trying to save the range instance
-        form_data = form.cleaned_data.copy()
-        product_range = form_data.get("range")
-        if product_range is not None:
-            form_data["range"] = product_range.id
-
-        combinations = form_data.get("combinations")
-        if combinations is not None:
-            form_data["combination_ids"] = [x.id for x in combinations]
-            del form_data["combinations"]
-
-        form_kwargs = {"data": form_data}
-        json_data = json.dumps(form_kwargs, cls=DjangoJSONEncoder)
-
-        session_data[self._key()] = json_data
-        self.request.session.save()
-
-    def _fetch_form_kwargs(self):
-        session_data = self.request.session.setdefault(self.wizard_name, {})
-        json_data = session_data.get(self._key(self.step_name), None)
-        if json_data:
-            return json.loads(json_data)
-
-        return {}
-
-    def _store_object(self, form):
-        session_data = self.request.session.setdefault(self.wizard_name, {})
-
-        # We don't store the object instance as that is not JSON serialisable.
-        # Instead, we save an alternative form
-        instance = form.save(commit=False)
-        # remove fields that do not exist (yet) on the uncommitted instance, i.e. m2m fields
-        cleanfields = [field.name for field in instance._meta.local_fields]
-
-        json_qs = serializers.serialize("json", [instance], fields=tuple(cleanfields))
-
-        session_data[self._key(is_object=True)] = json_qs
-        self.request.session.save()
-
-    def _fetch_object(self, step_name, request=None):
-        if request is None:
-            request = self.request
-        session_data = request.session.setdefault(self.wizard_name, {})
-        json_qs = session_data.get(self._key(step_name, is_object=True), None)
-        if json_qs:
-            # Recreate model instance from passed data
-            deserialised_obj = list(serializers.deserialize("json", json_qs))
-            return deserialised_obj[0].object
-
-    def _fetch_session_offer(self):
-        """Return the offer instance loaded with the data stored in the session.
-
-        When updating an offer, the updated fields are used with the existing
-        offer data.
-        """
-        offer = self._fetch_object("metadata")
-        if offer is None and self.update:
-            offer = self.offer
-        return offer
-
-    def _flush_session(self):
-        self.request.session[self.wizard_name] = {}
-        self.request.session.save()
-
-    def get_form_kwargs(self, *args, **kwargs):
-        form_kwargs = {}
-        if self.update:
-            form_kwargs["instance"] = self.get_instance()
-        session_kwargs = self._fetch_form_kwargs()
-        form_kwargs.update(session_kwargs)
-        parent_kwargs = super().get_form_kwargs(*args, **kwargs)
-        form_kwargs.update(parent_kwargs)
-        return form_kwargs
-
-    def get_context_data(self, **kwargs):
-        ctx = super().get_context_data(**kwargs)
-        if self.update:
-            ctx["offer"] = self.offer
-        ctx["session_offer"] = self._fetch_session_offer()
-        ctx["title"] = self.get_title()
-        return ctx
-
-    def get_back_url(self):
-        if not self.previous_view:
-            return None
-        if self.update:
-            return reverse(
-                self.previous_view.url_name, kwargs={"pk": self.kwargs["pk"]}
-            )
-        return reverse(self.previous_view.url_name)
-
-    def get_title(self):
-        return self.step_name.title()
-
-    def form_valid(self, form):
-        self._store_form_kwargs(form)
-        self._store_object(form)
-
-        if self.update and "save" in form.data:
-            # Save changes to this offer when updating and pressed save button
-            return self.save_offer(self.offer)
-        else:
-            # Proceed to next page
-            return super().form_valid(form)
-
-    def save_offer(self, offer):
-        # We update the offer with the name/description/offer_type from step 1
-        session_offer = self._fetch_session_offer()
-        offer.name = session_offer.name
-        offer.description = session_offer.description
-        offer.offer_type = session_offer.offer_type
-
-        # Save the related models, then save the offer.
-        # Note than you can save already on the first page of the wizard,
-        # so le'ts check if the benefit and condition exist
-        benefit = self._fetch_object("benefit")
-        if benefit:
-            benefit.save()
-            offer.benefit = benefit
-
-        condition = self._fetch_object("condition")
-        if condition:
-            condition.save()
-            offer.condition = condition
-
-        offer.save()
-
-        self._flush_session()
-
-        if self.update:
-            msg = _("Offer '%s' updated") % offer.name
-        else:
-            msg = _("Offer '%s' created!") % offer.name
-        messages.success(self.request, msg)
-
-        return HttpResponseRedirect(
-            reverse("dashboard:offer-detail", kwargs={"pk": offer.pk})
-        )
-
-    def get_success_url(self):
-        if self.update:
-            return reverse(self.success_url_name, kwargs={"pk": self.kwargs["pk"]})
-        return reverse(self.success_url_name)
-
-    @classmethod
-    def is_valid(cls, current_view, request):
-        if current_view.update:
-            return True
-        return current_view._fetch_object(cls.step_name, request) is not None
-
-
 class OfferMetaDataView(OfferWizardStepView):
     step_name = "metadata"
     form_class = MetaDataForm

src/oscar/apps/dashboard/offers/wizard_views.py

@@ -0,0 +1,191 @@
+import json
+
+from django.contrib import messages
+from django.core import serializers
+from django.core.serializers.json import DjangoJSONEncoder
+from django.http import HttpResponseRedirect
+from django.shortcuts import get_object_or_404
+from django.urls import reverse
+from django.utils.translation import gettext_lazy as _
+from django.views.generic import FormView
+
+from oscar.core.loading import get_model
+
+ConditionalOffer = get_model("offer", "ConditionalOffer")
+
+
+class OfferWizardStepView(FormView):
+    wizard_name = "offer_wizard"
+    form_class = None
+    step_name = None
+    update = False
+    url_name = None
+    success_url_name = "dashboard:offer-list"
+
+    # Keep a reference to previous view class to allow checks to be made on
+    # whether prior steps have been completed
+    previous_view = None
+
+    # pylint: disable=attribute-defined-outside-init
+    def dispatch(self, request, *args, **kwargs):
+        if self.update:
+            self.offer = get_object_or_404(ConditionalOffer, id=kwargs["pk"])
+        if not self.is_previous_step_complete(request):
+            messages.warning(
+                request,
+                _("%s step not complete") % (self.previous_view.step_name.title(),),
+            )
+            return HttpResponseRedirect(reverse(self.previous_view.url_name))
+        return super().dispatch(request, *args, **kwargs)
+
+    def is_previous_step_complete(self, request):
+        if not self.previous_view:
+            return True
+        return self.previous_view.is_valid(self, request)
+
+    def _key(self, step_name=None, is_object=False):
+        key = step_name if step_name else self.step_name
+        if self.update:
+            key += str(self.offer.id)
+        if is_object:
+            key += "_obj"
+        return key
+
+    def _store_form_kwargs(self, form):
+        session_data = self.request.session.setdefault(self.wizard_name, {})
+
+        # Adjust kwargs to avoid trying to save the range instance
+        form_data = form.cleaned_data.copy()
+        product_range = form_data.get("range")
+        if product_range is not None:
+            form_data["range"] = product_range.id
+
+        form_kwargs = {"data": form_data}
+        json_data = json.dumps(form_kwargs, cls=DjangoJSONEncoder)
+
+        session_data[self._key()] = json_data
+        self.request.session.save()
+
+    def _fetch_form_kwargs(self):
+        session_data = self.request.session.setdefault(self.wizard_name, {})
+        json_data = session_data.get(self._key(self.step_name), None)
+        if json_data:
+            return json.loads(json_data)
+
+        return {}
+
+    def _store_object(self, form):
+        session_data = self.request.session.setdefault(self.wizard_name, {})
+
+        # We don't store the object instance as that is not JSON serialisable.
+        # Instead, we save an alternative form
+        instance = form.save(commit=False)
+        # remove fields that do not exist (yet) on the uncommitted instance, i.e. m2m fields
+        cleanfields = [field.name for field in instance._meta.local_fields]
+
+        json_qs = serializers.serialize("json", [instance], fields=tuple(cleanfields))
+
+        session_data[self._key(is_object=True)] = json_qs
+        self.request.session.save()
+
+    def _fetch_object(self, step_name, request=None):
+        if request is None:
+            request = self.request
+        session_data = request.session.setdefault(self.wizard_name, {})
+        json_qs = session_data.get(self._key(step_name, is_object=True), None)
+        if json_qs:
+            # Recreate model instance from passed data
+            deserialised_obj = list(serializers.deserialize("json", json_qs))
+            return deserialised_obj[0].object
+
+    def _fetch_session_offer(self):
+        """Return the offer instance loaded with the data stored in the session.
+
+        When updating an offer, the updated fields are used with the existing
+        offer data.
+        """
+        offer = self._fetch_object("metadata")
+        if offer is None and self.update:
+            offer = self.offer
+        return offer
+
+    def _flush_session(self):
+        self.request.session[self.wizard_name] = {}
+        self.request.session.save()
+
+    def get_form_kwargs(self, *args, **kwargs):
+        form_kwargs = {}
+        if self.update:
+            form_kwargs["instance"] = self.get_instance()
+        session_kwargs = self._fetch_form_kwargs()
+        form_kwargs.update(session_kwargs)
+        parent_kwargs = super().get_form_kwargs(*args, **kwargs)
+        form_kwargs.update(parent_kwargs)
+        return form_kwargs
+
+    def get_context_data(self, **kwargs):
+        ctx = super().get_context_data(**kwargs)
+        if self.update:
+            ctx["offer"] = self.offer
+        ctx["session_offer"] = self._fetch_session_offer()
+        ctx["title"] = self.get_title()
+        return ctx
+
+    def get_title(self):
+        return self.step_name.title()
+
+    def form_valid(self, form):
+        self._store_form_kwargs(form)
+        self._store_object(form)
+
+        if self.update and "save" in form.data:
+            # Save changes to this offer when updating and pressed save button
+            return self.save_offer(self.offer)
+        else:
+            # Proceed to next page
+            return super().form_valid(form)
+
+    def save_offer(self, offer):
+        # We update the offer with the name/description/offer_type from step 1
+        session_offer = self._fetch_session_offer()
+        offer.name = session_offer.name
+        offer.description = session_offer.description
+        offer.offer_type = session_offer.offer_type
+
+        # Save the related models, then save the offer.
+        # Note than you can save already on the first page of the wizard,
+        # so le'ts check if the benefit and condition exist
+        benefit = self._fetch_object("benefit")
+        if benefit:
+            benefit.save()
+            offer.benefit = benefit
+
+        condition = self._fetch_object("condition")
+        if condition:
+            condition.save()
+            offer.condition = condition
+
+        offer.save()
+
+        self._flush_session()
+
+        if self.update:
+            msg = _("Offer '%s' updated") % offer.name
+        else:
+            msg = _("Offer '%s' created!") % offer.name
+        messages.success(self.request, msg)
+
+        return HttpResponseRedirect(
+            reverse("dashboard:offer-detail", kwargs={"pk": offer.pk})
+        )
+
+    def get_success_url(self):
+        if self.update:
+            return reverse(self.success_url_name, kwargs={"pk": self.kwargs["pk"]})
+        return reverse(self.success_url_name)
+
+    @classmethod
+    def is_valid(cls, current_view, request):
+        if current_view.update:
+            return True
+        return current_view._fetch_object(cls.step_name, request) is not None