Add weightage for Quiz and Create Grading System App

App Name: grades

Grading System provides with the grade for a given value.
It contains different grade ranges.

Has its own default grading system.
Allows you to modify and add grading system wth grade ranges.

To be done:
- Need to add README
- Good UI
- There are fields like can_be_used and order in models for future use.
- More tests

App name: Yaksh

Now every quiz has a default weightage of 100%, can be changed.
An aggregate is calculated for a given course.
Using grades app a grade is provide to the aggregate value.

1 files changed, 49 insertions, 0 deletions

diff --git a/grades/models.py b/grades/models.py
new file mode 100644
index 0000000..33895bb
--- /dev/null
+++ b/grades/models.py
@@ -0,0 +1,49 @@
+from django.db import models
+from django.contrib.auth.models import User
+
+# Create your models here.
+
+class GradingSystem(models.Model):
+    name = models.CharField(max_length=255, unique=True)
+    description = models.TextField(default='About the grading system!')
+    can_be_used = models.BooleanField(default=False)
+    creator = models.ForeignKey(User, null=True, blank=True)
+
+    def get_grade(self, marks):
+        ranges = self.graderange_set.all()
+        lower_limits = ranges.values_list('lower_limit', flat=True)
+        upper_limits = ranges.values_list('upper_limit', flat=True)
+        lower_limit = self._get_lower_limit(marks, lower_limits)
+        upper_limit = self._get_upper_limit(marks, upper_limits)
+        grade_range = ranges.filter(lower_limit=lower_limit,
+                                    upper_limit=upper_limit).first()
+        if grade_range:
+            return grade_range.grade
+
+    def _get_upper_limit(self, marks, upper_limits):
+        greater_than = [upper_limit for upper_limit in upper_limits
+                        if upper_limit > marks]
+        if greater_than:
+            return min(greater_than, key=lambda x: x-marks)
+
+    def _get_lower_limit(self, marks, lower_limits):
+        less_than = []
+        for lower_limit in lower_limits:
+            if lower_limit == marks:
+                return lower_limit
+            if lower_limit < marks:
+                less_than.append(lower_limit)
+        if less_than:
+            return max(less_than, key=lambda x: x-marks)
+
+    def __str__(self):
+        return self.name.title()
+
+
+class GradeRange(models.Model):
+    system = models.ForeignKey(GradingSystem)
+    order = models.IntegerField(default=0)
+    lower_limit = models.FloatField()
+    upper_limit = models.FloatField()
+    grade = models.CharField(max_length=10)
+    description = models.CharField(max_length=127, null=True, blank=True)