basic prompting framework

src/Mtlstats/Actions.hs

@@ -23,6 +23,8 @@ module Mtlstats.Actions
   ( startNewSeason
   , resetYtd
   , startNewGame
+  , addChar
+  , removeChar
   ) where
 
 import Lens.Micro (over, (&), (.~), (?~), (%~))
@@ -44,3 +46,11 @@ startNewGame :: ProgState -> ProgState
 startNewGame
   = (progMode .~ NewGame newGameState)
   . (database . dbGames %~ succ)
+
+-- | Adds a character to the input buffer
+addChar :: Char -> ProgState -> ProgState
+addChar = undefined
+
+-- | Removes a character from the input buffer (if possible)
+removeChar :: ProgState -> ProgState
+removeChar = undefined

src/Mtlstats/Prompt.hs

@@ -0,0 +1,74 @@
+{- |
+
+mtlstats
+Copyright (C) 2019 Rhéal Lamothe
+<rheal.lamothe@gmail.com>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+-}
+
+module Mtlstats.Prompt (
+  -- * Prompt Functions
+  drawPrompt,
+  promptHandler,
+) where
+
+import Control.Monad (when)
+import Control.Monad.Trans.State (gets, modify)
+import Data.Char (isDigit, toUpper)
+import Data.Foldable (forM_)
+import Lens.Micro ((^.), (.~), (?~))
+import Lens.Micro.Extras (view)
+import Text.Read (readMaybe)
+import qualified UI.NCurses as C
+
+import Mtlstats.Actions
+import Mtlstats.Types
+
+-- | Draws the prompt to the screen
+drawPrompt :: Prompt -> ProgState -> C.Update C.CursorMode
+drawPrompt p s = do
+  promptDrawer p s
+  return C.CursorVisible
+
+-- | Event handler for a prompt
+promptHandler :: Prompt -> C.Event -> Action ()
+promptHandler p (C.EventCharacter '\n') = do
+  val <- gets $ view inputBuffer
+  modify $ inputBuffer .~ ""
+  promptAction p val
+promptHandler p (C.EventCharacter c) = let
+  c' = toUpper c
+  in when (promptCharCheck p c') $
+   modify $ addChar c'
+promptHandler _ (C.EventSpecialKey C.KeyBackspace) =
+  modify removeChar
+promptHandler p (C.EventSpecialKey (C.KeyFunction k)) =
+  promptFunctionKey p k
+promptHandler _ _ = return ()
+
+-- | Builds a numeric prompt
+numPrompt
+  :: String
+  -- ^ The prompt string
+  -> (Int -> Action ())
+  -- ^ The callback function for the result
+  -> Prompt
+numPrompt pStr act = Prompt
+  { promptDrawer      = \s -> C.drawString $ pStr ++ s ^. inputBuffer
+  , promptCharCheck   = isDigit
+  , promptAction      = \inStr -> forM_ (readMaybe inStr) act
+  , promptFunctionKey = const $ return ()
+  }

src/Mtlstats/Types.hs

@@ -33,6 +33,7 @@ module Mtlstats.Types (
   PlayerStats (..),
   Goalie (..),
   GoalieStats (..),
+  Prompt (..),
   -- * Lenses
   -- ** ProgState Lenses
   database,
@@ -102,7 +103,7 @@ import Data.Aeson
   )
 import Lens.Micro (Lens', lens, (&), (^.), (.~))
 import Lens.Micro.TH (makeLenses)
-import UI.NCurses (Curses)
+import UI.NCurses (Curses, Update)
 
 -- | Action which maintains program state
 type Action a = StateT ProgState Curses a
@@ -308,6 +309,18 @@ instance ToJSON GoalieStats where
       "losses"        .= l  <>
       "ties"          .= t
 
+-- | Defines a user prompt
+data Prompt = Prompt
+  { promptDrawer      :: ProgState -> Update ()
+  -- ^ Draws the prompt to thr screen
+  , promptCharCheck   :: Char -> Bool
+  -- ^ Determines whether or not the character is valid
+  , promptAction      :: String -> Action ()
+  -- ^ Action to perform when the value is entered
+  , promptFunctionKey :: Integer -> Action ()
+  -- ^ Action to perform when a function key is pressed
+  }
+
 makeLenses ''ProgState
 makeLenses ''GameState
 makeLenses ''Database