Exercise feature in video lessons

Exercise is same as quiz except for following differences:
- no time limit
- no marks weightage
- no instruction page
- skip denied for a particular time

An attribute 'is_exercise' in Quiz determines whether the quiz is
exercise or not.
Questions contains 'min_time' attribute.
For an exercise a question cannot be skipped for an allotted minimum
time, after which either django or JavaScript makes Next button
available.

Implementation is as such due to complexity of our existing views and
templates.
Also, after min_time, same question with Next button is available to
move on, assuming that solution is present in the video.

1 files changed, 17 insertions, 3 deletions

diff --git a/yaksh/models.py b/yaksh/models.py
index c65e9ef..839043f 100644
--- a/yaksh/models.py
+++ b/yaksh/models.py
@@ -308,6 +308,8 @@ class Quiz(models.Model):
 
     weightage = models.FloatField(default=1.0)
 
+    is_exercise = models.BooleanField(default=False)
+
     creator = models.ForeignKey(User, null=True)
 
     objects = QuizManager()
@@ -747,6 +749,8 @@ class Question(models.Model):
     # Check assignment upload based question
     grade_assignment_upload = models.BooleanField(default=False)
 
+    min_time =  models.IntegerField("time in minutes", default=0)
+
     def consolidate_answer_data(self, user_answer, user=None):
         question_data = {}
         metadata = {}
@@ -1517,15 +1521,25 @@ class AnswerPaper(models.Model):
 
     def time_left(self):
         """Return the time remaining for the user in seconds."""
+        secs = self._get_total_seconds()
+        total = self.question_paper.quiz.duration*60.0
+        remain = max(total - secs, 0)
+        return int(remain)
+
+    def time_left_on_question(self, question):
+        secs = self._get_total_seconds()
+        total = question.min_time*60.0
+        remain = max(total - secs, 0)
+        return int(remain)
+
+    def _get_total_seconds(self):
         dt = timezone.now() - self.start_time
         try:
             secs = dt.total_seconds()
         except AttributeError:
             # total_seconds is new in Python 2.7. :(
             secs = dt.seconds + dt.days*24*3600
-        total = self.question_paper.quiz.duration*60.0
-        remain = max(total - secs, 0)
-        return int(remain)
+        return secs
 
     def _update_marks_obtained(self):
         """Updates the total marks earned by student for this paper."""