compute 1rm by choosing the best of multiple specified performances

1 files changed, 16 insertions, 17 deletions

diff --git a/repgoal.hs b/repgoal.hs
index afac135..a1c336c 100755
--- a/repgoal.hs
+++ b/repgoal.hs
@@ -63,36 +63,35 @@ import Brick.Util (fg, bg, on, clamp)
 import Brick.Widgets.Core
 import Brick.Widgets.Table
 
-data ExerciseStats = ExerciseStats {
-  exerciseName :: Text,
+data Performance = Achieved {
   achievedReps :: Integer,
   achievedWeight :: Rational
 }
 
 data ExerciseTarget = ExerciseTarget {
+  exerciseName :: Text,
   targetWeight :: Rational,
-  stats :: ExerciseStats
+  stats :: [Performance]
 }
 
 exercises :: [ExerciseTarget]
 exercises = [
-              ExerciseTarget 345 $ ExerciseStats "Deadlift" 9 315,
-              ExerciseTarget 130 $ ExerciseStats "Press" 9 120
+              ExerciseTarget "Deadlift" 345 $ [Achieved 5 360, Achieved 9 315],
+              ExerciseTarget "Press" 130 $ [Achieved 6 130, Achieved 9 120]
             ]
 
 computeRepGoal :: ExerciseTarget -> (Integer)
 computeRepGoal ExerciseTarget{..} = head $ filter isPR [2..]
   where
-    isPR n = let goal1rm = computeOneRepMax $ stats { achievedReps = n, achievedWeight = targetWeight }
-             in goal1rm > computeOneRepMax stats
-
--- The 1RM estimation formula from Jim Wendler's 5-3-1 Powerlifting
--- manual:
+    isPR n = computeOneRepMax (Achieved n targetWeight) > computeOneRepMax (bestPerformance stats)
 
--- Estimated 1 RM = Weight x Reps x 0.0333 + Weight.
+bestPerformance :: [Performance] -> Performance
+bestPerformance = head . sortBy (flip $ comparing computeOneRepMax)
 
-computeOneRepMax :: ExerciseStats -> Rational
-computeOneRepMax ExerciseStats{..} = achievedWeight * (realToFrac achievedReps * 0.0333 + 1)
+-- The formula from Jim Wendler's 5-3-1:
+-- 1RM = Weight x Reps x 0.0333 + Weight.
+computeOneRepMax :: Performance -> Rational
+computeOneRepMax Achieved{..} = achievedWeight * (realToFrac achievedReps * 0.0333 + 1)
 
 showRational :: Rational -> String
 showRational = printf "%.3f" . (realToFrac :: Rational -> Float)
@@ -103,14 +102,14 @@ drawUI () = [a]
     a = hCenter $ renderTable $ table $
         map str ["Exercise", "Achieved Reps", "Computed 1RM", "Goal Reps", "Goal+1"] : map toRow exercises
     toRow x@ExerciseTarget{..} =
-      let ExerciseStats{..} = stats
+      let best@Achieved{..} = bestPerformance stats
           repGoal = computeRepGoal x
-          goalTo1RM g = computeOneRepMax $ ExerciseStats exerciseName g targetWeight
+          goalTo1RM g = computeOneRepMax $ Achieved g targetWeight
       in
       [
-        txt exerciseName,
+        txt $ exerciseName,
         str $ printf "%d @ %s" achievedReps (showRational achievedWeight),
-        str $ showRational $ computeOneRepMax stats,
+        str $ showRational $ computeOneRepMax best,
         str $ printf "%d @ %s ≈ 1 @ %s" (repGoal) (showRational targetWeight) (showRational (goalTo1RM repGoal)),
         str $ printf "%d @ %s ≈ 1 @ %s" (repGoal + 1) (showRational targetWeight) (showRational (goalTo1RM $ repGoal + 1))
       ]