Switch to List for better performance

app/Main.hs

@@ -5,43 +5,15 @@ module Main where
 import           Brick
 import           Control.Monad
 import qualified Data.Text.IO          as T
-import qualified Graphics.Vty          as Vty
 import           Options.Applicative
 
+import           Profold.App
 import           Profold.Options
 import           Profold.ParseProfFile
-import           Profold.UiState
 
 data UiName = UiViewport
   deriving (Show, Eq, Ord)
 
-myAppDraw :: UiState -> [Widget UiName]
-myAppDraw s = [renderUiState UiViewport s]
-
-myHandleEvent :: UiState -> BrickEvent n e -> EventM n (Next UiState)
-myHandleEvent s (VtyEvent (Vty.EvKey Vty.KEsc _))         = halt s
-myHandleEvent s (VtyEvent (Vty.EvKey Vty.KUp _))          = continue $ moveFocusUp s
-myHandleEvent s (VtyEvent (Vty.EvKey Vty.KDown _))        = continue $ moveFocusDown s
-myHandleEvent s (VtyEvent (Vty.EvKey (Vty.KChar 'q') _))  = halt s
-myHandleEvent s (VtyEvent (Vty.EvKey (Vty.KChar 'k') _))  = continue $ moveFocusUp s
-myHandleEvent s (VtyEvent (Vty.EvKey (Vty.KChar 'j') _))  = continue $ moveFocusDown s
-myHandleEvent s (VtyEvent (Vty.EvKey (Vty.KChar '\t') _)) = continue $ toggleFold s
-myHandleEvent s  _                                        = continue s
-
-myAttrMap :: AttrMap
-myAttrMap = attrMap Vty.defAttr
-  [ ("focused", Vty.defAttr `Vty.withStyle` Vty.reverseVideo)
-  ]
-
-myApp :: App UiState () UiName
-myApp = App
-  { appDraw         = myAppDraw
-  , appChooseCursor = neverShowCursor
-  , appHandleEvent  = myHandleEvent
-  , appStartEvent   = pure
-  , appAttrMap      = const myAttrMap
-  }
-
 main :: IO ()
 main = do
   opts <- execParser options

src/Profold/App.hs

@@ -0,0 +1,83 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module Profold.App
+  ( UiState
+  , newUiState
+  , myApp
+  ) where
+
+import           Brick
+import           Brick.Widgets.List
+import qualified Data.Text          as T
+import qualified Data.Vector        as V
+import qualified Graphics.Vty       as Vty
+
+import           Profold.LineNode
+
+data UiName = UiList
+  deriving (Show, Eq, Ord)
+
+data UiState = UiState
+  { uiInfo :: [T.Text]
+  , uiTree :: LineNode
+  , uiList :: List UiName (Path, LineNode)
+  } deriving (Show)
+
+newUiState :: [T.Text] -> LineNode -> UiState
+newUiState info ln = UiState info ln $ list UiList (flatten ln) 1
+
+toggleFold :: UiState -> UiState
+toggleFold s = case listSelectedElement (uiList s) of
+  Nothing -> s
+  Just (i, (path, _)) ->
+    let newTree = modify toggleIfHasChildren path $ uiTree s
+        newList = listReplace (flatten newTree) (Just i) (uiList s)
+    in  s {uiTree = newTree, uiList = newList}
+  where
+    toggleIfHasChildren ln
+      | V.null $ lineChildren ln = ln
+      | otherwise = ln {lineFolded = not $ lineFolded ln}
+
+renderLine :: Bool -> (Path, LineNode) -> Widget UiName
+renderLine focused (_, ln)
+  | focused = visible $ withDefAttr "focused" widget
+  | otherwise = widget
+  where
+    prefix
+      | V.null $ lineChildren ln = " "
+      | lineFolded ln = "+"
+      | otherwise = "-"
+    widget = padRight Max $ str prefix <+> txt (lineText ln)
+
+renderUiState :: UiState -> Widget UiName
+renderUiState s =
+  let info = vBox $ map (\t -> str " " <+> txt t) $ uiInfo s
+  in  info <=> renderList renderLine True (uiList s)
+
+{- The actual App -}
+
+myAppDraw :: UiState -> [Widget UiName]
+myAppDraw s = [renderUiState s]
+
+myHandleEvent :: UiState -> BrickEvent UiName e -> EventM UiName (Next UiState)
+myHandleEvent s (VtyEvent (Vty.EvKey Vty.KEsc _))         = halt s
+myHandleEvent s (VtyEvent (Vty.EvKey (Vty.KChar 'q') _))  = halt s
+myHandleEvent s (VtyEvent (Vty.EvKey (Vty.KChar '\t') _)) = continue $ toggleFold s
+myHandleEvent s (VtyEvent e) = do
+  newList <- handleListEventVi handleListEvent e (uiList s)
+  continue s{uiList = newList}
+myHandleEvent s _ = continue s
+
+myAttrMap :: AttrMap
+myAttrMap = attrMap Vty.defAttr
+  [ ("focused", Vty.defAttr `Vty.withStyle` Vty.reverseVideo)
+  ]
+
+myApp :: App UiState () UiName
+myApp = App
+  { appDraw         = myAppDraw
+  , appChooseCursor = neverShowCursor
+  , appHandleEvent  = myHandleEvent
+  , appStartEvent   = pure
+  , appAttrMap      = const myAttrMap
+  }

src/Profold/UiState.hs

@@ -1,73 +0,0 @@
-{-# LANGUAGE OverloadedStrings #-}
-
-module Profold.UiState
-  ( UiState
-  , newUiState
-  -- * Modifying
-  , moveFocusUp
-  , moveFocusDown
-  , toggleFold
-  -- * Drawing
-  , renderUiState
-  ) where
-
-import           Brick
-import           Data.Maybe
-import qualified Data.Text        as T
-import qualified Data.Vector      as V
-
-import           Profold.LineNode
-import           Profold.Util
-
-data UiState = UiState
-  { uiInfo    :: [T.Text]
-  , uiTree    :: LineNode
-  , uiFocused :: Path
-  } deriving (Show)
-
-newUiState :: [T.Text] -> LineNode -> UiState
-newUiState info ln = UiState info ln []
-
-moveFocusUp :: UiState -> UiState
-moveFocusUp s =
-  fromMaybe s $ do
-    prev <-
-      fst <$> findSurrounding (\a -> fst a == uiFocused s) $
-      flatten $ uiTree s
-    pure s {uiFocused = fst prev}
-
-moveFocusDown :: UiState -> UiState
-moveFocusDown s =
-  fromMaybe s $ do
-    prev <-
-      snd <$> findSurrounding (\a -> fst a == uiFocused s) $
-      flatten $ uiTree s
-    pure s {uiFocused = fst prev}
-
-toggleFold :: UiState -> UiState
-toggleFold s =
-  s {uiTree = modify toggleFoldIfHasChildren (uiFocused s) (uiTree s)}
-  where
-    toggleFoldIfHasChildren ln
-      | V.null $ lineChildren ln = ln
-      | otherwise = ln {lineFolded = not $ lineFolded ln}
-
-wrapFocused :: Bool -> Widget n -> Widget n
-wrapFocused False = withDefAttr "unfocused"
-wrapFocused True  = visible . withDefAttr "focused"
-
-renderLine :: Bool -> LineNode -> Widget n
-renderLine focused ln =
-  let prefix
-        | V.null $ lineChildren ln = " "
-        | lineFolded ln = "+"
-        | otherwise = "-"
-  in  wrapFocused focused $ padRight Max $ str prefix <+> txt (lineText ln)
-
-renderUiState :: (Show n, Ord n) => n -> UiState -> Widget n
-renderUiState n s =
-  let info = vBox $ map txt $ uiInfo s
-      flat = V.toList $ flatten $ uiTree s
-      focused = uiFocused s
-      rendered = map (\(p, ln) -> renderLine (p == focused) ln) flat
-  in  info <=> viewport n Vertical (vBox rendered)