From 80add34b15855932e9201d7426d9df01aa82c845 Mon Sep 17 00:00:00 2001
From: Akshay Nair <phenax5@gmail.com>
Date: Sat, 14 Dec 2024 11:23:35 +0530
Subject: Add key sequence filtering and rendering matched keys

---
 src/Chelleport/KeySequence.hs | 80 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 src/Chelleport/KeySequence.hs

(limited to 'src/Chelleport/KeySequence.hs')

diff --git a/src/Chelleport/KeySequence.hs b/src/Chelleport/KeySequence.hs
new file mode 100644
index 0000000..1d118cd
--- /dev/null
+++ b/src/Chelleport/KeySequence.hs
@@ -0,0 +1,80 @@
+module Chelleport.KeySequence where
+
+import Data.List (isPrefixOf, nub)
+import qualified Data.Map as Map
+import qualified SDL
+
+safeHead :: a -> [a] -> a
+safeHead def [] = def
+safeHead _ (x : _) = x
+
+nextChars :: [Char] -> [[[Char]]] -> Maybe [Char]
+nextChars keys cells =
+  case matches of
+    [] -> Nothing
+    _ -> Just $ nub result
+  where
+    matches = concatMap (filter (isPrefixOf keys)) cells
+    result = concatMap (take 1 . drop (length keys)) matches
+
+isValidKey :: SDL.Keycode -> Bool
+isValidKey key = Map.member key keycodeMapping
+
+generateKeyCells :: (Int, Int) -> [Char] -> [[[Char]]]
+generateKeyCells (rows, columns) hintKeys =
+  (\row -> getCellSeq row <$> [1 .. columns]) <$> [1 .. rows]
+  where
+    getCellSeq x y = [getPrefix1 x y, getPrefix2 x y, getKey x y]
+    getKey _row col = hintKeys !! (col `mod` (columns `div` 2))
+    getPrefix1 _row col
+      | col <= (columns `div` 2) = 'H'
+      | otherwise = 'L'
+    getPrefix2 row _col
+      | row <= (rows `div` 2) = 'K'
+      | otherwise = 'J'
+
+toKeyChar :: SDL.Keycode -> Maybe Char
+toKeyChar key = Map.lookup key keycodeMapping
+
+eventToKeycode :: SDL.KeyboardEventData -> SDL.Keycode
+eventToKeycode = SDL.keysymKeycode . SDL.keyboardEventKeysym
+
+keycodeMapping :: Map.Map SDL.Keycode Char
+keycodeMapping =
+  Map.fromList
+    [ (SDL.KeycodeA, 'A'),
+      (SDL.KeycodeB, 'B'),
+      (SDL.KeycodeC, 'C'),
+      (SDL.KeycodeD, 'D'),
+      (SDL.KeycodeE, 'E'),
+      (SDL.KeycodeF, 'F'),
+      (SDL.KeycodeG, 'G'),
+      (SDL.KeycodeH, 'H'),
+      (SDL.KeycodeI, 'I'),
+      (SDL.KeycodeJ, 'J'),
+      (SDL.KeycodeK, 'K'),
+      (SDL.KeycodeL, 'L'),
+      (SDL.KeycodeM, 'M'),
+      (SDL.KeycodeN, 'N'),
+      (SDL.KeycodeO, 'O'),
+      (SDL.KeycodeP, 'P'),
+      (SDL.KeycodeR, 'R'),
+      (SDL.KeycodeS, 'S'),
+      (SDL.KeycodeT, 'T'),
+      (SDL.KeycodeU, 'U'),
+      (SDL.KeycodeV, 'V'),
+      (SDL.KeycodeW, 'W'),
+      (SDL.KeycodeX, 'X'),
+      (SDL.KeycodeY, 'Y'),
+      (SDL.KeycodeZ, 'Z'),
+      (SDL.Keycode0, '0'),
+      (SDL.Keycode1, '1'),
+      (SDL.Keycode2, '2'),
+      (SDL.Keycode3, '3'),
+      (SDL.Keycode4, '4'),
+      (SDL.Keycode5, '5'),
+      (SDL.Keycode6, '6'),
+      (SDL.Keycode7, '7'),
+      (SDL.Keycode8, '8'),
+      (SDL.Keycode9, '9')
+    ]
-- 
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