Brick: simple editor demo

Brick_Simple_Editor.hs

{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}

module Main where

import           Protolude
import           Prelude (unlines)
import           Brick ((<+>), (<=>))
import qualified Brick as B
import qualified Brick.Focus as BF
import qualified Brick.Widgets.Edit as BE
import qualified Brick.Widgets.Border as BB
import qualified Brick.Widgets.Border.Style as BBS
import qualified Graphics.Vty as V

main :: IO ()
main = do
  let g = St 0 (BF.focusRing [Edit1]) "" (BE.editor Edit1 Nothing "init")
  void $ B.customMain (V.mkVty V.defaultConfig) Nothing app g

data Name = ViewPort1
          | ViewPort2
          | Edit1
          deriving (Eq, Ord, Show)

data Tick = Tick
data St = St { gmScore :: Int
             , gmRing :: BF.FocusRing Name
             , gmText :: Text
             , gmEditor1 :: BE.Editor [Char] Name
             }

app :: B.App St Tick Name
app = B.App { B.appDraw = drawUI
            , B.appChooseCursor = B.showFirstCursor 
            , B.appHandleEvent = handleEvent
            , B.appStartEvent = pure
            , B.appAttrMap = const theMap
            }

handleEvent :: St -> B.BrickEvent Name Tick -> B.EventM Name (B.Next St)
handleEvent (St score r t e) (B.AppEvent Tick) = B.continue $ St (score + 1) r t e
handleEvent s (B.VtyEvent (V.EvKey V.KEsc [])) = B.halt s
handleEvent s (B.VtyEvent e) = do
  r <- BE.handleEditorEvent e (gmEditor1 s)
  B.continue $ s { gmEditor1 = r }
handleEvent s _ = B.continue s


drawUI :: St -> [B.Widget Name]
drawUI g =
  [ ( B.hLimit 50 $
      B.withBorderStyle BBS.unicodeRounded $
      BB.borderWithLabel (B.str "menu") $
      B.padAll 1 $
      B.viewport ViewPort1 B.Vertical $
      B.str "1"
    )
    <+>
    ( -- B.padLeft (B.Pad 2) $
      B.withBorderStyle BBS.unicodeRounded $
      BB.borderWithLabel (B.str "data") $
      B.padAll 1 $
      B.viewport ViewPort2 B.Vertical ( ( B.str "2" )
                                        <=>
                                        ( B.vLimit 5 $
                                          B.withBorderStyle BBS.unicode $
                                          BB.border $                                          
                                          BF.withFocusRing (gmRing g) (BE.renderEditor (B.str . unlines)) (gmEditor1 g)
                                        )
                                      )
    )
  ]


theMap :: B.AttrMap
theMap = B.attrMap V.defAttr 
    [ (BE.editAttr,        V.white `B.on` V.blue)
    , (BE.editFocusedAttr, V.black `B.on` V.yellow)
    ]