Fix #599 -- Add API to create orders (#911)

* [WIP] Fix #599 -- Add API to create orders

* Add more validation logic

* Add docs and some validation

* Fix test on MySQl

* Validation is fun, let's do more of it!

* Fix live_issues

src/pretix/base/models/event.py

@@ -545,7 +545,7 @@ class Event(EventMixin, LoggedModel):
     def has_payment_provider(self):
         result = False
         for provider in self.get_payment_providers().values():
-            if provider.is_enabled and provider.identifier != 'free':
+            if provider.is_enabled and provider.identifier not in ('free', 'boxoffice'):
                 result = True
                 break
         return result

src/pretix/base/models/orders.py

@@ -2,7 +2,7 @@ import copy
 import json
 import os
 import string
-from datetime import datetime, time
+from datetime import datetime, time, timedelta
 from decimal import Decimal
 from typing import Any, Dict, List, Union
 
@@ -218,11 +218,42 @@ class Order(LoggedModel):
             self.assign_code()
         if not self.datetime:
             self.datetime = now()
+        if not self.expires:
+            self.set_expires()
         super().save(**kwargs)
 
     def touch(self):
         self.save(update_fields=['last_modified'])
 
+    def set_expires(self, now_dt=None, subevents=None):
+        now_dt = now_dt or now()
+        tz = pytz.timezone(self.event.settings.timezone)
+        exp_by_date = now_dt.astimezone(tz) + timedelta(days=self.event.settings.get('payment_term_days', as_type=int))
+        exp_by_date = exp_by_date.astimezone(tz).replace(hour=23, minute=59, second=59, microsecond=0)
+        if self.event.settings.get('payment_term_weekdays'):
+            if exp_by_date.weekday() == 5:
+                exp_by_date += timedelta(days=2)
+            elif exp_by_date.weekday() == 6:
+                exp_by_date += timedelta(days=1)
+
+        self.expires = exp_by_date
+
+        term_last = self.event.settings.get('payment_term_last', as_type=RelativeDateWrapper)
+        if term_last:
+            if self.event.has_subevents and subevents:
+                term_last = min([
+                    term_last.datetime(se).date()
+                    for se in subevents
+                ])
+            else:
+                term_last = term_last.datetime(self.event).date()
+            term_last = make_aware(datetime.combine(
+                term_last,
+                time(hour=23, minute=59, second=59)
+            ), tz)
+            if term_last < self.expires:
+                self.expires = term_last
+
     @cached_property
     def tax_total(self):
         return (self.positions.aggregate(s=Sum('tax_value'))['s'] or 0) + (self.fees.aggregate(s=Sum('tax_value'))['s'] or 0)