From e00a2b074bc3a05461a1b674dfc1c3d9f4acfa18 Mon Sep 17 00:00:00 2001
From: Wolfgang Witt <Wolfgang.Witt@campus.lmu.de>
Date: Wed, 24 Mar 2021 12:28:19 +0100
Subject: [PATCH] chore: nudges for ExamRoomRandom have a bigger effect

---
 src/Handler/Utils/Exam.hs | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/src/Handler/Utils/Exam.hs b/src/Handler/Utils/Exam.hs
index 7734e05b5..324fd5498 100644
--- a/src/Handler/Utils/Exam.hs
+++ b/src/Handler/Utils/Exam.hs
@@ -317,9 +317,12 @@ examAutoOccurrence (hash -> seed) rule ExamAutoOccurrenceConfig{..} occurrences
              predToPositive 1 = Nothing
              predToPositive x = Just $ pred x
              extraCapacity :: Natural
-             extraCapacity
-              | restrictedSpace > numUnassignedUsers = restrictedSpace - numUnassignedUsers
-              | otherwise = 0
+             extraUsers :: Natural
+             (extraCapacity, extraUsers)
+              | restrictedSpace > numUnassignedUsers
+              = (restrictedSpace - numUnassignedUsers, 0)
+              | otherwise
+              = (0, numUnassignedUsers - restrictedSpace)
               where
                 restrictedSpace :: Natural
                 restrictedSpace = sum restrictedOccurrences
@@ -337,18 +340,32 @@ examAutoOccurrence (hash -> seed) rule ExamAutoOccurrenceConfig{..} occurrences
              nudgedUnrestrictedOccurrences = nudgedPositiveOccurrences unrestrictedPositiveNudges []
                                             ++ nudgedNegativeOccurrences unrestrictedNegativeNudges []
               where
+                replicateMany :: Int -> [a] -> [a]
+                replicateMany n as = take (n * length as) $ List.cycle as
+                nudgeEffect :: Int
+                nudgeEffect = max 1 $ ceiling $ eaocNudgeSize * fromIntegral extraUsers
                 -- for a positive nudge, add one entry to the front of the list
                 nudgedPositiveOccurrences :: Map ExamOccurrenceId Natural -> [ExamOccurrenceId] -> [ExamOccurrenceId]
                 nudgedPositiveOccurrences nudges acc
                   | null nudges = acc
                   | otherwise = nudgedPositiveOccurrences (Map.mapMaybe predToPositive nudges)
-                                  $ Set.toList (Set.intersection unrestrictedOccurrences $ Map.keysSet nudges) ++ acc
+                                  $ nudgeOccurrences' ++ acc
+                  where
+                    nudgeOccurrences :: [ExamOccurrenceId]
+                    nudgeOccurrences = Set.toList (Set.intersection unrestrictedOccurrences $ Map.keysSet nudges)
+                    nudgeOccurrences' :: [ExamOccurrenceId]
+                    nudgeOccurrences' = replicateMany nudgeEffect nudgeOccurrences
                 -- for a negative nudge, add one entry for every other unrestricted occurrence to the front of the list
                 nudgedNegativeOccurrences :: Map ExamOccurrenceId Natural ->[ExamOccurrenceId] -> [ExamOccurrenceId]
                 nudgedNegativeOccurrences nudges acc
                   | null nudges = acc
                   | otherwise = nudgedNegativeOccurrences (Map.mapMaybe predToPositive nudges)
-                                  $ Set.toList (Set.difference unrestrictedOccurrences $ Map.keysSet nudges) ++ acc
+                                  $ nudgeOccurrences' ++ acc
+                  where
+                    nudgeOccurrences :: [ExamOccurrenceId]
+                    nudgeOccurrences = Set.toList (Set.difference unrestrictedOccurrences $ Map.keysSet nudges)
+                    nudgeOccurrences' :: [ExamOccurrenceId]
+                    nudgeOccurrences' = replicateMany nudgeEffect nudgeOccurrences
              -- fill in users in a random order
              randomlyAssignedUsers :: Map UserId (Maybe ExamOccurrenceId)
              randomlyAssignedUsers = Map.fromList $ fillUnrestricted