From 86c4fe316e13afd486a6f4f80047e5649d756142 Mon Sep 17 00:00:00 2001
From: Jonathan Lamothe <jlamothe1980@gmail.com>
Date: Mon, 2 Dec 2019 20:48:09 -0500
Subject: [PATCH] correctly calculate goalie average

---
 ChangeLog.md          |  1 +
 src/Mtlstats/Types.hs |  8 +++++++-
 test/TypesSpec.hs     | 19 ++++++++++++-------
 3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/ChangeLog.md b/ChangeLog.md
index efb1001..6f2c900 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -5,6 +5,7 @@
 - Allow lower case player names
 - Don't show players without points in game report
 - Removed unnecessary goalie statistics from game report
+- Fixed goalie average calculation
 
 ## 0.7.0
 - Shortened views to fit within 25 lines
diff --git a/src/Mtlstats/Types.hs b/src/Mtlstats/Types.hs
index 6997628..c0162e6 100644
--- a/src/Mtlstats/Types.hs
+++ b/src/Mtlstats/Types.hs
@@ -1010,4 +1010,10 @@ addGoalieStats g1 g2 = GoalieStats
 
 -- | Determines a goalie's average goals allowed per game.
 gsAverage :: GoalieStats -> Rational
-gsAverage gs = fromIntegral (gs^.gsGoalsAllowed) / fromIntegral (gs^.gsGames)
+gsAverage gs = let
+  allowed = fromIntegral $ gs^.gsGoalsAllowed
+  mins    = fromIntegral $ gs^.gsMinsPlayed
+  gLen    = fromIntegral gameLength
+  in if mins == 0
+    then 0
+    else allowed / mins * gLen
diff --git a/test/TypesSpec.hs b/test/TypesSpec.hs
index 1744669..4237fd8 100644
--- a/test/TypesSpec.hs
+++ b/test/TypesSpec.hs
@@ -813,15 +813,20 @@ addGoalieStatsSpec = describe "addGoalieStats" $ let
     actual `shouldBe` expected
 
 gsAverageSpec :: Spec
-gsAverageSpec = describe "gsAverage" $ let
-  gs = newGoalieStats
-    & gsGames        .~ 2
-    & gsGoalsAllowed .~ 3
+gsAverageSpec = describe "gsAverage" $ mapM_
+  (\(label, stats, expected) -> context label $
+    it ("should be " ++ show expected) $
+      gsAverage stats `shouldBe` expected)
 
-  expected = 3 % 2
+  --  label,          stats,           expected
+  [ ( "with minutes", gs,              3 % 2    )
+  , ( "no minutes",   newGoalieStats , 0        )
+  ]
 
-  in it ("should be " ++ show expected) $
-    gsAverage gs `shouldBe` expected
+  where
+    gs = newGoalieStats
+      & gsMinsPlayed   .~ 2 * gameLength
+      & gsGoalsAllowed .~ 3
 
 joe :: Player
 joe = newPlayer 2 "Joe" "center"