Add view_duplicates

Add a way for admins to see duplicate (hence redundant) students
In prehistoric times, students with the same ID were allowed to be created twice
This feature allows admins to see obsolete Student objects

swd/main/urls.py

@@ -78,4 +78,6 @@
     url(r'^admin/get_cor_add', views.get_corr_address, name='get_corr_address'),
     url(r'^admin/delete_students/',views.delete_students, name='delete_students'),
 
+    url(r'^admin/view_duplicates/(?P<end_year>\d+)?/?', views.view_duplicates, name='view_duplicates'),
+
 ] + static(settings.STATIC_URL, document_root=settings.STATIC_ROOT) + static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)

swd/main/views.py

@@ -38,6 +38,68 @@
 
 from calendar import monthrange
 
+@user_passes_test(lambda a: a.is_superuser)
+def view_duplicates(request, end_year:str):
+    """
+    Shows duplicate students from year 2000 to the given end_year (default: current year)
+    URL: admin/view_duplicates/<optional end_year>
+    """
+    students = []
+
+    # If the end year isn't given, default to current year
+    if end_year == None:
+        end_year = datetime.now().year
+
+    years = [2000, int(end_year)+1]
+    for year in range(*years):
+        students.extend(Student.objects.filter(bitsId__startswith=str(year)))
+
+    # students -> list of Student objects in the given range of years
+
+    id_dict = {}
+    duplicate_list = []
+    nulls = []
+    fields = ['admit', 'bDay']
+    for idx, student in enumerate(students):
+        # If student hasn't been seen before
+        # Add to set of ids and continue
+        if not student.bitsId in id_dict:
+            id_dict[student.bitsId] = idx
+            continue
+
+        # At this point we know that `student` has been seen before
+
+        s1 = student
+        s2 = students[id_dict[student.bitsId]]
+
+        # Identify which of s1 and s2 is the inferior duplicate
+        inferior = None
+        master = None
+        for field in fields:
+            f1 = getattr(s1, field)
+            f2 = getattr(s2, field)
+            if f1==None and f2==None: continue
+            if f1!=None and f2!=None: continue
+            if f1:
+                master = s1 
+                inferior = s2
+                break
+            master = s2
+            inferior = s1
+            break
+        if inferior == None:
+            # Contingency in case somehow both objects have all fields
+            nulls.append(s1)
+        else:
+            duplicate_list.append([master, inferior])
+
+    # duplicate_list -> list of [master object, inferior object] lists
+
+    return render(request, "view_duplicates.html", {
+        "students": duplicate_list,
+        "start_year": 2000,
+        "end_year": end_year,
+    })
 
 def noPhD(func):
     def check(request, *args, **kwargs):

swd/templates/view_duplicates.html

@@ -0,0 +1,25 @@
+{% extends 'indexbase.html' %}
+
+{% block content %}
+
+<h3>Duplicate Students from {{ start_year }} to {{ end_year }} ({{ students|length }})</h3>
+
+<table class="centered bordered striped">
+    <tr>
+        <th style="text-align: center">More Details</th>
+        <th style="text-align: center">Less Details (Should be deleted)</th>
+        <th style="text-align: center">Name</th>
+        <th style="text-align: center">ID</th>
+    </tr>
+
+    {% for student_master,student_inferior in students %}
+    <tr align="center">
+        <td><a href="../main/student/{{student_master.pk}}/change/">{{ student_master.pk }}</a></td>
+        <td><a href="../main/student/{{student_inferior.pk}}/change/">{{ student_inferior.pk }}</a></td>
+        <td>{{ student_master.name }}</td>
+        <td>{{ student_master.bitsId }}</td>
+    </tr>
+    {% endfor %}
+</table>
+
+{% endblock %}