Fix #163 -- Form to change orders (#191)

src/pretix/control/forms/event.py

@@ -329,6 +329,12 @@ class MailSettingsForm(SettingsForm):
         widget=I18nTextarea,
         help_text=_("Available placeholders: {event}, {url}")
     )
+    mail_text_order_changed = I18nFormField(
+        label=_("Changed order"),
+        required=False,
+        widget=I18nTextarea,
+        help_text=_("Available placeholders: {event}, {url}")
+    )
     mail_text_resend_link = I18nFormField(
         label=_("Resend link"),
         required=False,

src/pretix/control/forms/orders.py

@@ -1,8 +1,10 @@
 from django import forms
+from django.core.exceptions import ValidationError
 from django.db import models
+from django.utils.translation import ugettext_lazy as _
 
 from pretix.base.forms import I18nModelForm
-from pretix.base.models import Order
+from pretix.base.models import Item, Order
 
 
 class ExtendForm(I18nModelForm):
@@ -35,3 +37,54 @@ class CommentForm(I18nModelForm):
                 'class': 'helper-width-100',
             }),
         }
+
+
+class OrderPositionChangeForm(forms.Form):
+    itemvar = forms.ChoiceField()
+    price = forms.DecimalField(
+        required=False,
+        max_digits=10, decimal_places=2,
+        label=_('New price')
+    )
+    operation = forms.ChoiceField(
+        required=False,
+        widget=forms.RadioSelect,
+        choices=(
+            ('product', 'Change product'),
+            ('price', 'Change price'),
+            ('cancel', 'Remove product')
+        )
+    )
+
+    def __init__(self, *args, **kwargs):
+        instance = kwargs.pop('instance')
+        initial = kwargs.get('initial', {})
+        if instance:
+            try:
+                if instance.variation:
+                    initial['itemvar'] = '%d-%d' % (instance.item.pk, instance.variation.pk)
+                elif instance.item:
+                    initial['itemvar'] = str(instance.item.pk)
+            except Item.DoesNotExist:
+                pass
+
+            initial['price'] = instance.price
+
+        kwargs['initial'] = initial
+        super().__init__(*args, **kwargs)
+        choices = []
+        for i in instance.order.event.items.prefetch_related('variations').all():
+            pname = i.name
+            if not i.is_available():
+                pname += ' ({})'.format(_('inactive'))
+            variations = list(i.variations.all())
+            if variations:
+                for v in variations:
+                    choices.append(('%d-%d' % (i.pk, v.pk), '%s – %s' % (pname, v.value)))
+            else:
+                choices.append((str(i.pk), pname))
+        self.fields['itemvar'].choices = choices
+
+    def clean(self):
+        if self.cleaned_data.get('operation') == 'price' and not self.cleaned_data.get('price', '') != '':
+            raise ValidationError(_('You need to enter a price if you want to change the product price.'))

src/pretix/control/forms/vouchers.py

@@ -3,7 +3,6 @@ import copy
 from django import forms
 from django.core.exceptions import ValidationError
 from django.db.models import Q
-from django.forms import model_to_dict
 from django.utils.timezone import now
 from django.utils.translation import ugettext_lazy as _
 

src/pretix/control/logdisplay.py

@@ -1,11 +1,50 @@
+import json
+from decimal import Decimal
+
 from django.dispatch import receiver
+from django.utils import formats
 from django.utils.translation import ugettext_lazy as _
 
+from pretix.base.models import Event, ItemVariation, LogEntry
 from pretix.base.signals import logentry_display
 
 
+def _display_order_changed(event: Event, logentry: LogEntry):
+    data = json.loads(logentry.data)
+
+    text = _('The order has been changed:')
+    if logentry.action_type == 'pretix.event.order.changed.item':
+        old_item = str(event.items.get(pk=data['old_item']))
+        if data['old_variation']:
+            old_item += ' - ' + str(event.itemvariations.get(pk=data['old_variation']))
+        new_item = str(event.items.get(pk=data['new_item']))
+        if data['new_variation']:
+            new_item += ' - ' + str(event.itemvariations.get(pk=data['new_variation']))
+        return text + ' ' + _('{old_item} ({old_price} {currency}) changed to {new_item} ({new_price} {currency}).').format(
+            old_item=old_item, new_item=new_item,
+            old_price=formats.localize(Decimal(data['old_price'])),
+            new_price=formats.localize(Decimal(data['new_price'])),
+            currency=event.currency
+        )
+    elif logentry.action_type == 'pretix.event.order.changed.price':
+        return text + ' ' + _('Price of a position changed from {old_price} {currency} to {new_price} {currency}.').format(
+            old_price=formats.localize(Decimal(data['old_price'])),
+            new_price=formats.localize(Decimal(data['new_price'])),
+            currency=event.currency
+        )
+    elif logentry.action_type == 'pretix.event.order.changed.cancel':
+        old_item = str(event.items.get(pk=data['old_item']))
+        if data['old_variation']:
+            old_item += ' - ' + str(ItemVariation.objects.get(pk=data['old_variation']))
+        return text + ' ' + _('{old_item} ({old_price} {currency}) removed.').format(
+            old_item=old_item,
+            old_price=formats.localize(Decimal(data['old_price'])),
+            currency=event.currency
+        )
+
+
 @receiver(signal=logentry_display, dispatch_uid="pretixcontrol_logentry_display")
-def pretixcontrol_logentry_display(sender, logentry, **kwargs):
+def pretixcontrol_logentry_display(sender: Event, logentry: LogEntry, **kwargs):
     plains = {
         'pretix.event.order.modified': _('The order details have been modified.'),
         'pretix.event.order.unpaid': _('The order has been marked as unpaid.'),
@@ -23,3 +62,6 @@ def pretixcontrol_logentry_display(sender, logentry, **kwargs):
     }
     if logentry.action_type in plains:
         return plains[logentry.action_type]
+
+    if logentry.action_type.startswith('pretix.event.order.changed'):
+        return _display_order_changed(sender, logentry)

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

@@ -16,6 +16,7 @@
             {% bootstrap_field form.mail_text_order_paid layout="horizontal" %}
             {% bootstrap_field form.mail_text_order_free layout="horizontal" %}
             {% bootstrap_field form.mail_text_resend_link layout="horizontal" %}
+            {% bootstrap_field form.mail_text_order_changed layout="horizontal" %}
         </fieldset>
         <fieldset>
             <legend>{% trans "SMTP settings" %}</legend>

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

@@ -0,0 +1,105 @@
+{% extends "pretixcontrol/event/base.html" %}
+{% load i18n %}
+{% load bootstrap3 %}
+{% block title %}
+    {% blocktrans trimmed with code=order.code %}
+        Change order: {{ code }}
+    {% endblocktrans %}
+{% endblock %}
+{% block content %}
+    <h1>
+        {% blocktrans trimmed with code=order.code %}
+            Change order: {{ code }}
+        {% endblocktrans %}
+    </h1>
+    <p>
+        {% blocktrans trimmed %}
+            You can use this tool to change the ordered products or to partially cancel the order. Please keep
+            in mind that changing an order can have several implications, e.g. the payment method fee might change or
+            additional questions can be added to the order that need to be answered by the user.
+        {% endblocktrans %}
+    </p>
+    <p>
+        {% blocktrans trimmed %}
+            The user will receive a notification about the change but in the case of new required questions, the user
+            will not be forced to answer them. You cannot use this form to add something to the order, please create
+            a second order instead.
+        {% endblocktrans %}
+    </p>
+    <p>
+        {% blocktrans trimmed %}
+            If an invoice is attached to the order, a cancellation will be created together with a new invoice.
+        {% endblocktrans %}
+    </p>
+    <div class="alert alert-warning">
+        {% blocktrans trimmed %}
+            Please use this tool carefully. Changes you make here are not reversible. In most cases it is easier to
+            cancel the order completely and create a new one.
+        {% endblocktrans %}
+    </div>
+    <form method="post" class="form-horizontal" href="">
+        {% csrf_token %}
+        {% for position in positions %}
+            <div class="panel panel-default items">
+                <div class="panel-heading">
+                    <h3 class="panel-title">
+                        <strong>{{ position.item.name }}</strong>
+                        {% if position.variation %}
+                            – {{ position.variation }}
+                        {% endif %}
+                    </h3>
+                </div>
+                <div class="panel-body">
+                    <div class="form-inline form-order-change">
+                        {% bootstrap_form_errors position.form %}
+                        {% if position.custom_error %}
+                            <div class="alert alert-danger">
+                                {{ position.custom_error }}
+                            </div>
+                        {% endif %}
+                        <div class="radio">
+                            <label>
+                                <input name="{{ position.form.prefix }}-operation" type="radio" value=""
+                                        {% if not position.form.operation.value %}checked="checked"{% endif %}>
+                                {% trans "Keep unchanged" %}
+                            </label>
+                        </div>
+                        <div class="radio">
+                            <label>
+                                <input name="{{ position.form.prefix }}-operation" type="radio" value="product"
+                                        {% if position.form.operation.value == "product" %}checked="checked"{% endif %}>
+                                {% trans "Change product to" %}
+                                {% bootstrap_field position.form.itemvar layout='inline' %}
+                            </label>
+                        </div>
+                        <div class="radio">
+                            <label>
+                                <input name="{{ position.form.prefix }}-operation" type="radio" value="price"
+                                        {% if position.form.operation.value == "price" %}checked="checked"{% endif %}>
+                                {% trans "Change price to" %}
+                                {% bootstrap_field position.form.price layout='inline' %}
+                            </label>
+                        </div>
+                        <div class="radio">
+                            <label>
+                                <input name="{{ position.form.prefix }}-operation" type="radio" value="cancel"
+                                        {% if position.form.operation.value == "cancel" %}checked="checked"{% endif %}>
+                                {% trans "Remove from order" %}
+                            </label>
+                        </div>
+                    </div>
+                </div>
+            </div>
+        {% endfor %}
+        <div class="form-group submit-group">
+            <a class="btn btn-default btn-lg"
+                    href="{% url "control:event.order" event=request.event.slug organizer=request.event.organizer.slug code=order.code %}">
+                {% trans "Cancel" %}
+            </a>
+            <button class="btn btn-primary btn-save btn-lg" type="submit">
+                {% trans "Perform changes" %}
+            </button>
+            <div class="clearfix"></div>
+        </div>
+    </form>
+{% endblock %}

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

@@ -148,6 +148,14 @@
             </div>
             <div class="panel panel-default items">
                 <div class="panel-heading">
+                    <div class="pull-right">
+                        {% if order.status == "n" and request.eventperm.can_change_orders %}
+                            <a href="{% url "control:event.order.change" event=request.event.slug organizer=request.event.organizer.slug code=order.code %}">
+                                <span class="fa fa-edit"></span>
+                                {% trans "Change products" %}
+                            </a>
+                        {% endif %}
+                    </div>
                     <h3 class="panel-title">
                         {% trans "Ordered items" %}
                     </h3>

src/pretix/control/urls.py

@@ -83,6 +83,8 @@ urlpatterns = [
             name='event.order.extend'),
         url(r'^orders/(?P<code>[0-9A-Z]+)/comment$', orders.OrderComment.as_view(),
             name='event.order.comment'),
+        url(r'^orders/(?P<code>[0-9A-Z]+)/change$', orders.OrderChange.as_view(),
+            name='event.order.change'),
         url(r'^orders/(?P<code>[0-9A-Z]+)/$', orders.OrderDetail.as_view(), name='event.order'),
         url(r'^orders/(?P<code>[0-9A-Z]+)/download/(?P<output>[^/]+)$', orders.OrderDownload.as_view(),
             name='event.order.download'),

src/pretix/control/views/orders.py

@@ -13,7 +13,8 @@ from django.views.generic import DetailView, ListView, TemplateView, View
 
 from pretix.base.i18n import language
 from pretix.base.models import (
-    CachedFile, CachedTicket, EventLock, Invoice, Item, Order, Quota,
+    CachedFile, CachedTicket, EventLock, Invoice, Item, ItemVariation, Order,
+    Quota,
 )
 from pretix.base.services import tickets
 from pretix.base.services.export import export
@@ -22,13 +23,17 @@ from pretix.base.services.invoices import (
     regenerate_invoice,
 )
 from pretix.base.services.mail import SendMailException, mail
-from pretix.base.services.orders import cancel_order, mark_order_paid
+from pretix.base.services.orders import (
+    OrderChangeManager, OrderError, cancel_order, mark_order_paid,
+)
 from pretix.base.services.stats import order_overview
 from pretix.base.signals import (
     register_data_exporters, register_payment_providers,
     register_ticket_outputs,
 )
-from pretix.control.forms.orders import CommentForm, ExporterForm, ExtendForm
+from pretix.control.forms.orders import (
+    CommentForm, ExporterForm, ExtendForm, OrderPositionChangeForm,
+)
 from pretix.control.permissions import EventPermissionRequiredMixin
 from pretix.multidomain.urlreverse import build_absolute_uri
 
@@ -77,6 +82,12 @@ class OrderView(EventPermissionRequiredMixin, DetailView):
             code=self.kwargs['code'].upper()
         )
 
+    def _redirect_back(self):
+        return redirect('control:event.order',
+                        event=self.request.event.slug,
+                        organizer=self.request.event.organizer.slug,
+                        code=self.order.code)
+
     @cached_property
     def order(self):
         return self.get_object()
@@ -441,12 +452,6 @@ class OrderExtend(OrderView):
         else:
             return self.get(*args, **kwargs)
 
-    def _redirect_back(self):
-        return redirect('control:event.order',
-                        event=self.request.event.slug,
-                        organizer=self.request.event.organizer.slug,
-                        code=self.order.code)
-
     def get(self, *args, **kwargs):
         if self.order.status != Order.STATUS_PENDING:
             messages.error(self.request, _('This action is only allowed for pending orders.'))
@@ -462,6 +467,75 @@ class OrderExtend(OrderView):
                           data=self.request.POST if self.request.method == "POST" else None)
 
 
+class OrderChange(OrderView):
+    permission = 'can_change_orders'
+    template_name = 'pretixcontrol/order/change.html'
+
+    def dispatch(self, request, *args, **kwargs):
+        if self.order.status != Order.STATUS_PENDING:
+            messages.error(self.request, _('This action is only allowed for pending orders.'))
+            return self._redirect_back()
+        return super().dispatch(request, *args, **kwargs)
+
+    @cached_property
+    def positions(self):
+        positions = list(self.order.positions.all())
+        for p in positions:
+            p.form = OrderPositionChangeForm(prefix='op-{}'.format(p.pk), instance=p,
+                                             data=self.request.POST if self.request.method == "POST" else None)
+        return positions
+
+    def get_context_data(self, **kwargs):
+        ctx = super().get_context_data(**kwargs)
+        ctx['positions'] = self.positions
+        return ctx
+
+    def post(self, *args, **kwargs):
+        ocm = OrderChangeManager(self.order, self.request.user)
+        form_valid = True
+        for p in self.positions:
+            if not p.form.is_valid():
+                print(p.pk, 'Form invalid')
+                form_valid = False
+                break
+
+            try:
+                if p.form.cleaned_data['operation'] == 'product':
+                    if '-' in p.form.cleaned_data['itemvar']:
+                        itemid, varid = p.form.cleaned_data['itemvar'].split('-')
+                    else:
+                        itemid, varid = p.form.cleaned_data['itemvar'], None
+
+                    item = Item.objects.get(pk=itemid, event=self.request.event)
+                    if varid:
+                        variation = ItemVariation.objects.get(pk=varid, item=item)
+                    else:
+                        variation = None
+                    ocm.change_item(p, item, variation)
+                elif p.form.cleaned_data['operation'] == 'price':
+                    ocm.change_price(p, p.form.cleaned_data['price'])
+                elif p.form.cleaned_data['operation'] == 'cancel':
+                    ocm.cancel(p)
+
+            except OrderError as e:
+                p.custom_error = str(e)
+                form_valid = False
+                break
+
+        if not form_valid:
+            messages.error(self.request, _('An error occured. Please see the details below.'))
+        else:
+            try:
+                ocm.commit()
+            except OrderError as e:
+                messages.error(self.request, str(e))
+            else:
+                messages.success(self.request, _('The order has been changed and the user has been notified.'))
+                return self._redirect_back()
+
+        return self.get(*args, **kwargs)
+
+
 class OverView(EventPermissionRequiredMixin, TemplateView):
     template_name = 'pretixcontrol/orders/overview.html'
     permission = 'can_view_orders'