From 3346a8e15b6015e0409ae960b0e22d579771b544 Mon Sep 17 00:00:00 2001
From: Erik Stein <erik@classlibrary.net>
Date: Mon, 27 Aug 2018 15:52:03 +0200
Subject: [PATCH] Added RuntimeMixin.

---
 shared/utils/models/events.py | 114 ++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 shared/utils/models/events.py

diff --git a/shared/utils/models/events.py b/shared/utils/models/events.py
new file mode 100644
index 0000000..8ba820f
--- /dev/null
+++ b/shared/utils/models/events.py
@@ -0,0 +1,114 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+import datetime
+
+from django.conf import settings
+from django.core.exceptions import ValidationError
+from django.db import models
+from django.utils.translation import ugettext_lazy as _
+
+from shared.utils.dateformat import format_partial_date, format_date_range
+
+
+USE_TRANSLATABLE_FIELDS = getattr(settings, 'CONTENT_USE_TRANSLATABLE_FIELDS', False)
+# TODO Implement translatable AutoSlugField: USE_TRANSLATABLE_SLUG_FIELDS = getattr(settings, 'CONTENT_USE_TRANSLATABLE_SLUG_FIELDS', True)
+
+if USE_TRANSLATABLE_FIELDS:
+    from shared.multilingual.utils.fields import TranslatableCharField
+else:
+    TranslatableCharField = models.CharField
+
+
+# FIXME Currently Python cannot handle BC dates
+#       Possibly solution: https://github.com/okfn/datautil/blob/master/datautil/date.py
+MIN_DATE = datetime.date.min
+MAX_DATE = datetime.date.max
+
+
+class RuntimeMixin(models.Model):
+    """Allows a model to have partially defined from-/to-dates;
+    at least one year value must be entered.
+    """
+    from_year_value = models.PositiveIntegerField(_("starting year"), null=True, blank=True)
+    from_month_value = models.PositiveIntegerField(_("starting month"), null=True, blank=True)
+    from_day_value = models.PositiveIntegerField(_("starting day"), null=True, blank=True)
+    _from_sort_date = models.DateField(_("from"), editable=False)
+    until_year_value = models.PositiveIntegerField(_("ending year"), null=True, blank=True)
+    until_month_value = models.PositiveIntegerField(_("ending month"), null=True, blank=True)
+    until_day_value = models.PositiveIntegerField(_("ending day"), null=True, blank=True)
+    _until_sort_date = models.DateField(_("until"), editable=False)
+
+    runtime_text = TranslatableCharField(_("Zeitangabe Textform"),
+        max_length=200, null=True, blank=True,
+        help_text=_("Alternativer Text für die Laufzeitangabe"))
+
+    class Meta:
+        abstract = True
+
+    def clean(self):
+        if not (self.from_year_value or self.until_year_value):
+            raise ValidationError(_('Please enter either a from or an until date year.'))
+
+        # Update from/sort date fields
+        if self.from_year_value:
+            self._from_sort_date = datetime.date(
+                self.from_year_value, self.from_month_value or 1, self.from_day_value or 1)
+        else:
+            self._from_sort_date = MIN_DATE
+
+        if self.until_year_value:
+            self._until_sort_date = datetime.date(
+                self.until_year_value, self.until_month_value or 12, self.until_day_value or 31)
+        else:
+            self._until_sort_date = MAX_DATE
+
+    def save(self, *args, **kwargs):
+        self.full_clean()
+        super(RuntimeMixin, self).save(*args, **kwargs)
+
+    @property
+    def from_date(self):
+        return self._from_sort_date
+
+    @property
+    def until_date(self):
+        return self._until_sort_date
+
+    # TODO Implement @fron_date.setter, @until_date.setter
+
+    def get_from_display(self):
+        return self.runtime_text or format_partial_date(
+            self.from_year_value,
+            self.from_month_value,
+            self.from_day_value)
+    get_from_display.admin_order_field = '_from_sort_date'
+    get_from_display.short_description = _("from")
+
+    def get_until_display(self):
+        if self.runtime_text:
+            return ""
+        else:
+            return format_partial_date(
+                self.until_year_value,
+                self.until_month_value,
+                self.until_day_value)
+    get_until_display.admin_order_field = '_until_sort_date'
+    get_until_display.short_description = _("until")
+
+    def get_runtime_display(self):
+        # TODO Improve
+        if not self.runtime_text and \
+           self.from_day_value and self.from_month_value:
+            return format_date_range(self._from_sort_date, self._until_sort_date)
+        else:
+            f = self.get_from_display()
+            # Single point
+            if self._from_sort_date == self._until_sort_date:
+                return f
+
+            u = self.get_until_display()
+            if f and u:
+                return "{}–{}".format(f, u)
+            else:
+                return f or u