UI for settings propagation

src/pretix/control/templates/pretixcontrol/event/base.html

@@ -8,7 +8,7 @@
         <a href="{% url 'control:event.index' organizer=request.event.organizer.slug event=request.event.slug %}"
                 {% if url_name == "event.index" %}class="active"{% endif %}>
             <i class="fa fa-dashboard fa-fw"></i>
-            {% trans "Dashboard" %}
+            {% trans "Event dashboard" %}
         </a>
     </li>
     {% if 'can_change_event_settings' in request.eventpermset %}

src/pretix/control/templates/pretixcontrol/event/display.html

@@ -1,18 +1,25 @@
 {% extends "pretixcontrol/event/settings_base.html" %}
 {% load i18n %}
 {% load bootstrap3 %}
+{% load hierarkey_form %}
 {% block inside %}
     <form action="" method="post" class="form-horizontal" enctype="multipart/form-data">
         {% csrf_token %}
         {% bootstrap_form_errors form %}
         <fieldset>
-            <legend>{% trans "Display settings" %}</legend>
-            {% bootstrap_field form.primary_color layout="horizontal" %}
-            {% bootstrap_field form.primary_font layout="horizontal" %}
+            <legend>{% trans "Event page" %}</legend>
             {% bootstrap_field form.logo_image layout="horizontal" %}
             {% bootstrap_field form.frontpage_text layout="horizontal" %}
             {% bootstrap_field form.show_variations_expanded layout="horizontal" %}
         </fieldset>
+        <fieldset>
+            <legend>{% trans "Shop design" %}</legend>
+            {% url "control:organizer.display" organizer=request.organizer.slug as org_url %}
+            {% propagated request.event org_url "primary_color" "primary_font" %}
+                {% bootstrap_field form.primary_color layout="horizontal" %}
+                {% bootstrap_field form.primary_font layout="horizontal" %}
+            {% endpropagated %}
+        </fieldset>
         <div class="form-group submit-group">
             <button type="submit" class="btn btn-primary btn-save">
                 {% trans "Save" %}

src/pretix/control/templatetags/hierarkey_form.py

@@ -0,0 +1,68 @@
+from django import template
+from django.template import Node
+from django.utils.translation import ugettext as _
+
+register = template.Library()
+
+
+class PropagatedNode(Node):
+    def __init__(self, nodelist, event, field_names, url):
+        self.nodelist = nodelist
+        self.event = template.Variable(event)
+        self.field_names = field_names
+        self.url = template.Variable(url)
+
+    def render(self, context):
+        event = self.event.resolve(context)
+        url = self.url.resolve(context)
+        body = self.nodelist.render(context)
+
+        if all([fn not in event.settings._cache() for fn in self.field_names]):
+            body = """
+            <div class="propagated-settings-box">
+                <input type="hidden" name="_settings_ignore" value="{fnames}">
+                <div class="propagated-settings-form blurred">
+                    {body}
+                </div>
+                <div class="propagated-settings-overlay">
+                    <h4><span class="fa fa-link"></span> {text_inh}</h4>
+                    <p>
+                        {text_expl}
+                    </p>
+                    <button class="btn btn-default" name="decouple" value="{fnames}" data-action="unlink">
+                        <span class="fa fa-unlink"></span> {text_unlink}
+                    </button>
+                    <a class="btn btn-default" href="{url}" target="_blank">
+                        <span class="fa fa-group"></span> {text_orga}
+                    </a>
+                </div>
+            </div>
+            """.format(
+                body=body,
+                text_inh=_("Organizer-level settings"),
+                fnames=','.join(self.field_names),
+                text_expl=_(
+                    'These settings are currently set on organizer level. This way, you can easily change them for '
+                    'all of your events at the same time. You can either go to the organizer settings to change them '
+                    'or decouple them from the organizer account to change them for this event individually.'
+                ),
+                text_unlink=_('Change only for this event'),
+                text_orga=_('Change for all events'),
+                url=url
+            )
+
+        return body
+
+
+@register.tag
+def propagated(parser, token):
+    try:
+        tag, event, url, *args = token.split_contents()
+    except ValueError:
+        raise template.TemplateSyntaxError(
+            "%r tag requires at least three arguments" % token.contents.split()[0]
+        )
+
+    nodelist = parser.parse(('endpropagated',))
+    parser.delete_first_token()
+    return PropagatedNode(nodelist, event, [f[1:-1] for f in args], url)

src/pretix/control/views/event.py

@@ -328,11 +328,23 @@ class EventSettingsFormView(EventPermissionRequiredMixin, FormView):
         kwargs['obj'] = self.request.event
         return kwargs
 
+    def _save_decoupled(self, form):
+        # Save fields that are currently only set via the organizer but should be decoupled
+        fields = set()
+        for f in self.request.POST.getlist("decouple"):
+            fields |= set(f.split(","))
+        for f in fields:
+            if f not in form.fields:
+                continue
+            if f not in self.request.event.settings._cache():
+                self.request.event.settings.set(f, self.request.event.settings.get(f))
+
     @transaction.atomic
     def post(self, request, *args, **kwargs):
         form = self.get_form()
         if form.is_valid():
             form.save()
+            self._save_decoupled(form)
             if form.has_changed():
                 self.request.event.log_action(
                     'pretix.event.settings', user=self.request.user, data={
@@ -394,6 +406,7 @@ class DisplaySettings(EventSettingsViewMixin, EventSettingsFormView):
         form = self.get_form()
         if form.is_valid():
             form.save()
+            self._save_decoupled(form)
             if form.has_changed():
                 self.request.event.log_action(
                     'pretix.event.settings', user=self.request.user, data={