Show history in sheets (refs #349)

1 files changed, 21 insertions, 4 deletions

diff --git a/ishtar/furnitures/models.py b/ishtar/furnitures/models.py
index 2fe65b598..de519076f 100644
--- a/ishtar/furnitures/models.py
+++ b/ishtar/furnitures/models.py
@@ -174,15 +174,32 @@ class BaseHistorizedItem(models.Model):
         super(BaseHistorizedItem, self).save(*args, **kwargs)
         return True
 
-    def get_previous(self, step, strict=True):
+    def get_previous(self, step=None, date=None, strict=True):
         """
         Get a "step" previous state of the item
         """
+        assert step or date
         historized = self.history.all()
-        assert len(historized) > step
-        assert not hasattr(historized, '_step')
-        item = historized[step]
+        item = None
+        if step:
+            assert len(historized) > step
+            item = historized[step]
+        else:
+            for step, item in enumerate(historized):
+                if item.history_date == date:
+                    break
+            # ended with no match
+            if item.history_date != date:
+                return
         item._step = step
+        if len(historized) != (step + 1):
+            item._previous = historized[step + 1].history_date
+        else:
+            item._previous = None
+        if step > 0:
+            item._next = historized[step - 1].history_date
+        else:
+            item._next = None
         model = self.__class__
         for k in model._meta.get_all_field_names():
             field = model._meta.get_field_by_name(k)[0]