add lesson footer

[edumed.git] / catalogue / models.py

diff --git a/catalogue/models.py b/catalogue/models.py
index 0c3a54c..f1c5377 100644 (file)
--- a/catalogue/models.py
+++ b/catalogue/models.py
@@ -35,7 +35,7 @@ class Section(models.Model):
             lessons = [Lesson.objects.get(slug=part.slug)
                         for part in wldoc.book_info.parts]
         except Lesson.DoesNotExist, e:
-            raise cls.IncompleteError(e)
+            raise cls.IncompleteError(part.slug)
 
         slug = wldoc.book_info.url.slug
         try:
@@ -173,6 +173,24 @@ class Lesson(models.Model):
     def get_syntetic(self):
         return self.section.syntetic_lesson(self.level)
 
+    def get_previous(self):
+        if self.section is None: return None
+        try:
+            return self.section.lesson_set.filter(
+                type=self.type, level=self.level,
+                order__lt=self.order).order_by('-order')[0]
+        except IndexError:
+            return None
+
+    def get_next(self):
+        if self.section is None: return None
+        try:
+            return self.section.lesson_set.filter(
+                type=self.type, level=self.level,
+                order__gt=self.order).order_by('order')[0]
+        except IndexError:
+            return None
+
 
 class Attachment(models.Model):
     slug = models.CharField(max_length=255)