move source bounds to BoundsMixin

src/c3nav/mapdata/models/base.py

@@ -1,6 +1,7 @@
 from collections import OrderedDict
 
 from django.db import models
+from django.utils.translation import ugettext_lazy as _
 
 EDITOR_FORM_MODELS = OrderedDict()
 
@@ -38,3 +39,30 @@ class EditorFormMixin(SerializableMixin, models.Model):
     @property
     def title(self):
         return self._meta.verbose_name+' '+str(self.id)
+
+
+class BoundsMixin(SerializableMixin, models.Model):
+    bottom = models.DecimalField(_('bottom coordinate'), max_digits=6, decimal_places=2)
+    left = models.DecimalField(_('left coordinate'), max_digits=6, decimal_places=2)
+    top = models.DecimalField(_('top coordinate'), max_digits=6, decimal_places=2)
+    right = models.DecimalField(_('right coordinate'), max_digits=6, decimal_places=2)
+
+    class Meta:
+        abstract = True
+
+    @classmethod
+    def max_bounds(cls):
+        result = cls.objects.all().aggregate(models.Min('bottom'), models.Min('left'),
+                                             models.Max('top'), models.Max('right'))
+        return ((float(result['bottom__min']), float(result['left__min'])),
+                (float(result['top__max']), float(result['right__max'])))
+
+    def _serialize(self, section=True, **kwargs):
+        result = super()._serialize(**kwargs)
+        result['bounds'] = self.bounds
+        return result
+
+    @property
+    def bounds(self):
+        # noinspection PyTypeChecker
+        return (float(self.bottom), float(self.left)), (float(self.top), float(self.right))