feat: initial minimax implementation (quite slow!)

Proj2.hs

@@ -49,8 +49,10 @@ module Proj2
 where
 
 import Data.List
+import Data.Ord (comparing)
 import Data.Set qualified as S
 import Debug.Trace
+import Text.XHtml (target)
 
 -- ==== DATA STRUCTURES =======================================================
 
@@ -174,10 +176,22 @@ initialGuess = (bestFirstGuess, allChords)
 --  2. TODO: mini-max?
 --
 nextGuess :: ([Pitch], GameState) -> (Int, Int, Int) -> ([Pitch], GameState)
+-- nextGuess (prevGuess, chords) answer | trace ("calling nextGuess with: " ++ show prevGuess ++ show chords ++ show answer) False = undefined
 nextGuess (prevGuess, chords) answer = (guess, consistentChords)
   where
-    guess : consistentChords = filter consistentWithAnswer chords
-    consistentWithAnswer chord = answer == feedback prevGuess chord
+    consistentChords = filter (consistentWith answer) chords
+    scoredGuesses = map (\x -> (x, averageNumTargets x)) consistentChords
+    guess = fst $ minimumBy (comparing snd) scoredGuesses
+
+    -- helper functions
+    consistentWith answer chord = answer == feedback prevGuess chord
+    averageNumTargets answer = map (`squaredFreqs` consistentChords) consistentChords
+    squaredFreqs answer = map ((^ 2) . length) . group . sort . map (feedback answer)
+    averageFreqs answer chords = sum freqs `div` length freqs
+      where
+        freqs = squaredFreqs answer chords
+
+-- TODO: implement me
 
 -- ==== HELPER FUNCTIONS ======================================================