Add sub-events and relative date settings (#503)

* Data model

* little crud

* SubEventItemForm etc

* Drop SubEventItem.active, quota editor

* Fix failing tests

* First frontend stuff

* Addons form stuff

* Quota calculation

* net price display on EventIndex

* Add tests, solve some bugs

* Correct quota selection in more places, consolidate pricing logic

* Fix failing quota tests

* Fix TypeError

* Add tests for checkout

* Fixed a bug in QuotaForm

* Prevent immutable cart if a quota was removed from an item

* Add tests for pricing

* Handle waiting list

* Filter in check-in list

* Fixed import lost in rebase

* Fix waiting list widget

* Voucher management

* Voucher redemption

* Fix broken tests

* Add subevents to OrderChangeManager

* Create a subevent during event creation

* Fix bulk voucher creation

* Introduce subevent.active

* Copy from for subevents

* Show active in list

* ICal download for subevents

* Check start and end of presale

* Failing tests / show cart logic

* Test

* Rebase migrations

* REST API integration of sub-events

* Integrate quota calculation into the traditional quota form

* Make subevent argument to add_position optional

* Log-display foo

* pretixdroid and subevents

* Filter by subevent

* Add more tests

* Some mor tests

* Rebase fixes

* More tests

* Relative dates

* Restrict selection in relative datetime widgets

* Filter subevent list

* Re-label has_subevents

* Rebase fixes, subevents in calendar view

* Performance and caching issues

* Refactor calendar templates

* Permission tests

* Calendar fixes and month selection

* subevent selection

* Rename subevents to dates

* Add tests for calendar views

src/pretix/control/templates/pretixcontrol/order/change.html

@@ -81,6 +81,16 @@
                                 {% bootstrap_field position.form.itemvar layout='inline' %}
                             </label>
                         </div>
+                        {% if request.event.has_subevents %}
+                            <div class="radio">
+                                <label>
+                                    <input name="{{ position.form.prefix }}-operation" type="radio" value="subevent"
+                                            {% if position.form.operation.value == "subevent" %}checked="checked"{% endif %}>
+                                    {% trans "Change date to" context "subevent" %}
+                                    {% bootstrap_field position.form.subevent layout='inline' %}
+                                </label>
+                            </div>
+                        {% endif %}
                         <div class="radio">
                             <label>
                                 <input name="{{ position.form.prefix }}-operation" type="radio" value="price"
@@ -128,6 +138,9 @@
                     {% if add_form.addon_to %}
                         {% bootstrap_field add_form.addon_to layout='horizontal' %}
                     {% endif %}
+                    {% if add_form.subevent %}
+                        {% bootstrap_field add_form.subevent layout='horizontal' %}
+                    {% endif %}
                 </div>
             </div>
         </div>

src/pretix/control/templates/pretixcontrol/order/index.html

@@ -184,6 +184,9 @@
                                         {{ line.voucher.code }}
                                     </a>
                                 {% endif %}
+                                {% if line.subevent %}
+                                    <br /><span class="fa fa-calendar"></span> {{ line.subevent.name }} &middot; {{ line.subevent.get_date_range_display }}
+                                {% endif %}
                                 {% if line.has_questions %}
                                     <dl>
                                         {% if line.item.admission and event.settings.attendee_names_asked %}