show validity of hamming code

src/Hamming/App.hs

@@ -29,7 +29,7 @@ module Hamming.App (mainApp, initialState) where
 import Brick.AttrMap (attrMap)
 import Brick.Main (App (..), showFirstCursor)
 import Brick.Util (fg, style)
-import Graphics.Vty.Attributes (bold)
+import Graphics.Vty.Attributes (Attr (..), MaybeDefault (..), bold)
 import Graphics.Vty.Attributes.Color (green, red)
 
 import Hamming.App.Draw
@@ -44,9 +44,15 @@ mainApp = App
   , appHandleEvent  = eventHandler
   , appStartEvent   = return ()
   , appAttrMap      = const $ attrMap (style 0)
-    [ ( marginAttr, fg green    )
-    , ( checkAttr,  style bold )
-    , ( zeroAttr,   fg red     )
+    [ ( marginAttr,  fg green   )
+    , ( checkAttr,   style bold )
+    , ( zeroAttr,    fg red     )
+    , ( validAttr
+      , (style bold) { attrForeColor = SetTo green }
+      )
+    , ( invalidAttr
+      , (style bold) { attrForeColor = SetTo red }
+      )
     ]
   }
 

src/Hamming/App/Widgets.hs

@@ -30,6 +30,8 @@ module Hamming.App.Widgets (
   -- ** Attribute Names
   hammingAttr,
   marginAttr,
+  validAttr,
+  invalidAttr,
   bodyAttr,
   checkAttr,
   zeroAttr,

src/Hamming/App/Widgets/Internal.hs

@@ -35,6 +35,8 @@ module Hamming.App.Widgets.Internal (
   -- ** Attribute Names
   hammingAttr,
   marginAttr,
+  validAttr,
+  invalidAttr,
   bodyAttr,
   checkAttr,
   zeroAttr,
@@ -46,12 +48,16 @@ import Lens.Micro (_2, (^.), (%~))
 import Brick.AttrMap (AttrName, attrName)
 import Brick.Types (Location)
 
+import Hamming
 import Hamming.App.Types
 import Hamming.App.Util
 
 hammingW' :: AppState -> ([[(AttrName, Char)]], Maybe Location)
 hammingW' state = let
-  header = (hammingAttr, ' ') : map (marginAttr,) ['0'..'3']
+  valid = if isValid (state^.hammingCode)
+    then (validAttr, '✓')
+    else (invalidAttr, 'X')
+  header = valid : map (marginAttr,) ['0'..'3']
   body   = hammingBody state
   widget = header : zipWith
     (\n row -> (marginAttr, n) : row)
@@ -65,6 +71,12 @@ hammingAttr = attrName "hamming"
 marginAttr :: AttrName
 marginAttr = hammingAttr <> attrName "margin"
 
+validAttr :: AttrName
+validAttr = marginAttr <> attrName "valid"
+
+invalidAttr :: AttrName
+invalidAttr = marginAttr <> attrName "invalid"
+
 bodyAttr :: AttrName
 bodyAttr = hammingAttr <> attrName "body"