Certificate model for tracking certificate statuses

lms/djangoapps/certificates/models.py

@@ -7,71 +7,68 @@ Certificates are created for a student and an offering of a course.
 
 When a certificate is generated, a unique ID is generated so that
 the certificate can be verified later. The ID is a UUID4, so that
-it can't be easily guessed and so that it is unique. Even though
-we save these generated certificates (for later verification), we
-also record the UUID so that if we regenerate the certificate it
-will have the same UUID.
+it can't be easily guessed and so that it is unique. 
 
 Certificates are generated in batches by a cron job, when a
 certificate is available for download the GeneratedCertificate
 table is updated with information that will be displayed
 on the course overview page.
 
-
 '''
 
+class CertificateStatuses(object):
+    unavailable='unavailable'
+    generating='generating'
+    regenerating='regenerating'
+    deleting='deleting'
+    deleted='deleted'
+    downloadable='downloadable'
+    error='error'
 
 class GeneratedCertificate(models.Model):
     user = models.ForeignKey(User)
-    course_id = models.CharField(max_length=255, default=False)
-    certificate_id = models.CharField(max_length=32, default=False)
-    graded_certificate_id = models.CharField(max_length=32, default=False)
-
-    download_url = models.CharField(max_length=128, default=False)
-    graded_download_url = models.CharField(max_length=128, default=False)
-    grade = models.CharField(max_length=5, default=False)
-    key = models.CharField(max_length=32, default=False)
-
-    # enabled should only be true if the student has earned a passing grade
-    # in the course.
-    enabled = models.BooleanField(default=False)
-
-
-def certificate_state_for_student(student):
+    course_id = models.CharField(max_length=255, blank=True, default='')
+    verify_uuid = models.CharField(max_length=32, blank=True, default='')
+    download_uuid = models.CharField(max_length=32, blank=True, default='')
+    download_url = models.CharField(max_length=128, blank=True,  default='')
+    grade = models.CharField(max_length=5, blank=True, default='')
+    key = models.CharField(max_length=32, blank=True, default='')
+    distinction = models.BooleanField(default=False)
+    status = models.CharField(max_length=32, default='unavailable')
+
+    class Meta:
+        unique_together= (('user', 'course_id'),)
+
+def certificate_status_for_student(student, course_id):
     '''
-    This returns a dictionary with a key for state, and other information.
-    The state is one of the following:
+    This returns a dictionary with a key for status, and other information.
+    The status is one of the following:
 
     unavailable  - A student is not eligible for a certificate.
-    generating   - A student has requested a certificate,
-                   but it is not generated yet.
-    downloadable - The certificate has been requested and is
-                   available for download.
-
-    If the state is "downloadable", the dictionary also contains
-    "download_url" and "graded_download_url".
+    generating   - A request has been made to generate a certificate,
+                   but it has not been generated yet.
+    regenerating - A request has been made to regenerate a certificate,
+                   but it has not been generated yet. 
+    deleting     - A request has been made to delete a certificate.
+    
+    deleted      - The certificate has been deleted.
+    downloadable - The certificate is available for download.
+
+    If the status is "downloadable", the dictionary also contains
+    "download_url".
 
     '''
 
     try:
         generated_certificate = GeneratedCertificate.objects.get(
-                user=student)
-        if generated_certificate.enabled:
-            if generated_certificate.download_url:
-                return {
-                      'state': 'downloadable',
-                      'download_url':
-                        generated_certificate.download_url,
-                      'graded_download_url':
-                        generated_certificate.graded_download_url
-                       }
-            else:
-                return {'state': 'generating'}
-        else:
-            # If enabled=False, there is no certificate available
-            # Our output will be the same as if the
-            # GeneratedCertificate did not exist
-            pass
+                user=student, course_id=course_id)
+        if generated_certificate.status == CertificateStatuses.downloadable:
+            return {
+                      'status': CertificateStatuses.downloadable,
+                      'download_url': generated_certificate.download_url,
+                   }
+        else: 
+            return {'status': generated_certificate.status}
     except GeneratedCertificate.DoesNotExist:
         pass
-    return {'state': 'unavailable'}
+    return {'status': 'unavailable'}