Merge pull request #103 from ThommyH/fixWorkingTimeCalculation

Fix working time calculation

app/models/exercise.rb

@@ -82,23 +82,111 @@ class Exercise < ActiveRecord::Base
   def get_quantiles(quantiles)
     quantiles_str = "[" + quantiles.join(",") + "]"
     result = self.class.connection.execute("""
-      SELECT unnest(PERCENTILE_CONT(ARRAY#{quantiles_str}) WITHIN GROUP (ORDER BY working_time))
+            WITH working_time AS
-      FROM
+      (
-          (
+               SELECT   user_id,
-            SELECT user_id,
+                        id,
-                   sum(working_time_new) AS working_time
+                        exercise_id,
-            FROM
+                        Max(score)                                                                                  AS max_score,
-              (SELECT user_id,
+                        (created_at - Lag(created_at) OVER (partition BY user_id, exercise_id ORDER BY created_at)) AS working_time
-                      CASE WHEN working_time >= '0:30:00' THEN '0' ELSE working_time END AS working_time_new
+               FROM     submissions
-               FROM
+               WHERE    exercise_id = #{id}
-                  (SELECT user_id,
+               AND      user_type = 'ExternalUser'
-                          id,
+               GROUP BY user_id,
-                          (created_at - lag(created_at) OVER (PARTITION BY user_id, exercise_id
+                        id,
-                                                              ORDER BY created_at)) AS working_time
+                        exercise_id), max_points AS
-                  FROM submissions
+      (
-                  WHERE exercise_id=#{self.id} AND user_type = 'ExternalUser') AS foo) AS bar
+               SELECT   context_id  AS ex_id,
-            GROUP BY user_id
+                        Sum(weight) AS max_points
-      ) AS foo
+               FROM     files
+               WHERE    context_type = 'Exercise'
+               AND      context_id = #{id}
+               AND      role = 'teacher_defined_test'
+               GROUP BY context_id),
+      -- filter for rows containing max points
+      time_max_score AS
+      (
+             SELECT *
+             FROM   working_time W1,
+                    max_points MS
+             WHERE  w1.exercise_id = ex_id
+             AND    w1.max_score = ms.max_points),
+      -- find row containing the first time max points
+      first_time_max_score AS
+      (
+             SELECT id,
+                    user_id,
+                    exercise_id,
+                    max_score,
+                    working_time,
+                    rn
+             FROM   (
+                             SELECT   id,
+                                      user_id,
+                                      exercise_id,
+                                      max_score,
+                                      working_time,
+                                      Row_number() OVER(partition BY user_id, exercise_id ORDER BY id ASC) AS rn
+                             FROM     time_max_score) T
+             WHERE  rn = 1), times_until_max_points AS
+      (
+             SELECT w.id,
+                    w.user_id,
+                    w.exercise_id,
+                    w.max_score,
+                    w.working_time,
+                    m.id AS reachedmax_at
+             FROM   working_time W,
+                    first_time_max_score M
+             WHERE  w.user_id = m.user_id
+             AND    w.exercise_id = m.exercise_id
+             AND    w.id <= m.id),
+      -- if user never makes it to max points, take all times
+      all_working_times_until_max AS (
+      (
+             SELECT id,
+                    user_id,
+                    exercise_id,
+                    max_score,
+                    working_time
+             FROM   times_until_max_points)
+      UNION ALL
+                (
+                       SELECT id,
+                              user_id,
+                              exercise_id,
+                              max_score,
+                              working_time
+                       FROM   working_time W1
+                       WHERE  NOT EXISTS
+                              (
+                                     SELECT 1
+                                     FROM   first_time_max_score F
+                                     WHERE  f.user_id = w1.user_id
+                                     AND    f.exercise_id = w1.exercise_id))), filtered_times_until_max AS
+      (
+             SELECT user_id,
+                    exercise_id,
+                    max_score,
+                    CASE
+                           WHEN working_time >= '0:30:00' THEN '0'
+                           ELSE working_time
+                    END AS working_time_new
+             FROM   all_working_times_until_max ), result AS
+      (
+               SELECT   e.external_id AS external_user_id,
+                        f.user_id,
+                        exercise_id,
+                        Max(max_score)        AS max_score,
+                        Sum(working_time_new) AS working_time
+               FROM     filtered_times_until_max f,
+                        external_users e
+               WHERE    f.user_id = e.id
+               GROUP BY e.external_id,
+                        f.user_id,
+                        exercise_id )
+      SELECT   unnest(percentile_cont(array#{quantiles_str}) within GROUP (ORDER BY working_time))
+      FROM     result
     """)
     if result.count > 0
       quantiles.each_with_index.map{|q,i| Time.parse(result[i]["unnest"]).seconds_since_midnight}
@@ -133,15 +221,54 @@ class Exercise < ActiveRecord::Base
   def accumulated_working_time_for_only(user)
     user_type = user.external_user? ? "ExternalUser" : "InternalUser"
     Time.parse(self.class.connection.execute("""
-      SELECT sum(working_time_new) AS working_time
+        WITH WORKING_TIME AS
-      FROM
+        (SELECT user_id,
-        (SELECT CASE WHEN working_time >= '0:30:00' THEN '0' ELSE working_time END AS working_time_new
+                           id,
-         FROM
+                           exercise_id,
-            (SELECT id,
+                           max(score) AS max_score,
-                    (created_at - lag(created_at) over (PARTITION BY user_id, exercise_id
+                           (created_at - lag(created_at) OVER (PARTITION BY user_id, exercise_id
-                                                        ORDER BY created_at)) AS working_time
+                                                               ORDER BY created_at)) AS working_time
-            FROM submissions
+                   FROM submissions
-            WHERE exercise_id=#{id} and user_id=#{user.id} and user_type='#{user_type}') AS foo) AS bar
+                   WHERE exercise_id = #{id} AND user_id = #{user.id} AND user_type = '#{user_type}'
+                   GROUP BY user_id, id, exercise_id),
+        MAX_POINTS AS
+        (SELECT context_id AS ex_id, sum(weight) AS max_points FROM files WHERE context_type = 'Exercise' AND context_id = #{id} AND role = 'teacher_defined_test' GROUP BY context_id),
+
+        -- filter for rows containing max points
+        TIME_MAX_SCORE AS
+        (SELECT *
+        FROM WORKING_TIME W1, MAX_POINTS MS
+        WHERE W1.exercise_id = ex_id AND W1.max_score = MS.max_points),
+
+        -- find row containing the first time max points
+        FIRST_TIME_MAX_SCORE AS
+        ( SELECT id,USER_id,exercise_id,max_score,working_time, rn
+          FROM (
+            SELECT id,USER_id,exercise_id,max_score,working_time,
+                ROW_NUMBER() OVER(PARTITION BY user_id, exercise_id ORDER BY id ASC) AS rn
+            FROM TIME_MAX_SCORE) T
+         WHERE rn = 1),
+
+        TIMES_UNTIL_MAX_POINTS AS (
+            SELECT W.id, W.user_id, W.exercise_id, W.max_score, W.working_time, M.id AS reachedmax_at
+            FROM WORKING_TIME W, FIRST_TIME_MAX_SCORE M
+            WHERE W.user_id = M.user_id AND W.exercise_id = M.exercise_id AND W.id <= M.id),
+
+        -- if user never makes it to max points, take all times
+        ALL_WORKING_TIMES_UNTIL_MAX AS
+        ((SELECT id, user_id, exercise_id, max_score, working_time FROM TIMES_UNTIL_MAX_POINTS)
+        UNION ALL
+        (SELECT id, user_id, exercise_id, max_score, working_time FROM WORKING_TIME W1
+         WHERE NOT EXISTS (SELECT 1 FROM FIRST_TIME_MAX_SCORE F WHERE F.user_id = W1.user_id AND F.exercise_id = W1.exercise_id))),
+
+        FILTERED_TIMES_UNTIL_MAX AS
+        (
+        SELECT user_id,exercise_id, max_score, CASE WHEN working_time >= '0:30:00' THEN '0' ELSE working_time END AS working_time_new
+        FROM ALL_WORKING_TIMES_UNTIL_MAX
+        )
+            SELECT e.external_id AS external_user_id, f.user_id, exercise_id, MAX(max_score) AS max_score, sum(working_time_new) AS working_time
+            FROM FILTERED_TIMES_UNTIL_MAX f, EXTERNAL_USERS e
+            WHERE f.user_id = e.id GROUP BY e.external_id, f.user_id, exercise_id
     """).first["working_time"] || "00:00:00").seconds_since_midnight
   end