add management command to link current and previous questions

Defaults to matching question numbers across sessions but allows
overrides for where there is not a direct match

Fixes #142

Author: struan

crowdsourcer/management/commands/link_questions.py

@@ -0,0 +1,106 @@
+from collections import defaultdict
+
+from django.core.management.base import BaseCommand
+
+import pandas as pd
+
+from crowdsourcer.models import MarkingSession, Question, Section
+
+
+class Command(BaseCommand):
+    help = "set up question links to previous session"
+
+    overrides = {}
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            "--current",
+            action="store",
+            required=True,
+            help="The current session",
+        )
+
+        parser.add_argument(
+            "--previous",
+            action="store",
+            required=True,
+            help="The previous session",
+        )
+
+        parser.add_argument(
+            "--overrides", action="store", help="CSV file with list of link overrides"
+        )
+
+    def get_overrides(self, file):
+        df = pd.read_csv(file)
+
+        overrides = defaultdict(dict)
+        for _, row in df.iterrows():
+            overrides[row["section"]][str(row["current_question"])] = str(
+                row["previous_question"]
+            )
+
+        self.overrides = overrides
+
+    def get_session(self, session_label):
+        try:
+            ms = MarkingSession.objects.get(label=session_label)
+        except MarkingSession.DoesNotExist:
+            ms = None
+
+        return ms
+
+    def setup_sessions(self, *args, **kwargs):
+        setup = True
+
+        for session in ("current", "previous"):
+            ms = self.get_session(kwargs[session])
+            if ms is not None:
+                setattr(self, session, ms)
+            else:
+                setup = False
+                self.stderr.write(
+                    f"Could not find {session} session: {kwargs[session]}"
+                )
+
+        return setup
+
+    def get_questions(self, session):
+        questions = defaultdict(dict)
+
+        for section in Section.objects.filter(marking_session=session):
+            for question in Question.objects.filter(section=section):
+                questions[section.title][question.number_and_part] = question
+
+        return questions
+
+    def handle(self, *args, **kwargs):
+        sessions_exist = self.setup_sessions(*args, **kwargs)
+        if not sessions_exist:
+            return
+
+        if kwargs.get("overrides") is not None:
+            self.get_overrides(kwargs["overrides"])
+
+        current_questions = self.get_questions(self.current)
+        previous_questions = self.get_questions(self.previous)
+
+        for section, questions in current_questions.items():
+            for q_no, question in questions.items():
+                overrides = self.overrides.get(section, None)
+                if overrides is not None and overrides.get(q_no) is not None:
+                    prev_question_no = overrides.get(q_no, q_no)
+                    self.stdout.write(
+                        f"Using previous question {prev_question_no} for {question} in {section}"
+                    )
+                else:
+                    prev_question_no = q_no
+
+                if previous_questions[section].get(prev_question_no) is None:
+                    self.stderr.write(f"No matching question for {q_no} in {section}")
+                    continue
+                else:
+                    prev_question = previous_questions[section][prev_question_no]
+
+                question.previous_question = prev_question
+                question.save()