.files/nix/configurations/vanadium/home/xmonad/lib/Leanamonad/Layout/ReflectMsg.hs

{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}

module Leanamonad.Layout.ReflectMsg where

import XMonad (
  Resize (Expand, Shrink),
  SomeMessage (SomeMessage),
  fromMessage,
 )

import XMonad.Layout.LayoutModifier (
  LayoutModifier (handleMess, handleMessOrMaybeModifyIt),
  ModifiedLayout (ModifiedLayout),
 )

data ReflectMsg a = ReflectMsg deriving (Show, Read)

reflectMsg :: l a -> ModifiedLayout ReflectMsg l a
reflectMsg = ModifiedLayout ReflectMsg

instance LayoutModifier ReflectMsg a where
  handleMessOrMaybeModifyIt m mess
    | Just Shrink <- fromMessage mess = return . Just . Right $ SomeMessage Expand
    | Just Expand <- fromMessage mess = return . Just . Right $ SomeMessage Shrink
    -- Handle the rest by passing it on
    | otherwise = do
        mm <- handleMess m mess
        return (Left <$> mm)