ghcup-hs/lib-tui/GHCup/Brick/Widgets/Menu.hs

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{-# LANGUAGE CPP #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ViewPatterns #-}
{-# OPTIONS_GHC -Wno-unused-record-wildcards #-}
{-# OPTIONS_GHC -Wno-unused-matches #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE InstanceSigs #-}
{-# LANGUAGE GADTs #-}
{- **************
A general system inspired by Brick.Form. It uses optics instead of microlenses and it is less generic than
Brick.Form, but generic enough to serve our purpose.
A Menu consists in
a) A state value
b) A list of fields. Each field is capable of modifying a part of the state
c) some metadata
A field (type MenuField) consists in
a) a Lens to a part of the Menu state, so the Menu can call that lens to modify its own state
b) an input widget
An input (type FieldInput) consist in
a) some state
b) a validator function
c) a handler and a renderer
We have to use existential types to achive a composable API since every FieldInput has a different
internal type, and every MenuField has a different Lens. For example:
- The menu state is a record (MyRecord {uri: URI, flag : Bool})
- Then, there are two MenuField:
- One MenuField has (Lens' MyRecord URI) and the other has (Lens' MyRecord Bool)
- The MenuFields has FieldInputs with internal state Text and Bool, respectively
- Obviously, the MenuField has to be polimorphic in the Lens' and in the Input internal state,
But we must hide that polimorphisim (existential), in order to store all MenuField in a List
************** -}
module GHCup.Brick.Widgets.Menu where
import qualified GHCup.Brick.Attributes as Attributes
import qualified GHCup.Brick.Common as Common
import Brick
( BrickEvent(..),
EventM,
Widget(..),
(<+>))
import qualified Brick
import qualified Brick.Widgets.Border as Border
import qualified Brick.Widgets.List as L
import qualified Brick.Widgets.Edit as Edit
import Brick.Focus (FocusRing)
import qualified Brick.Focus as F
import Data.Function ( (&))
import Prelude hiding ( appendFile )
import qualified Data.Text as T
import Optics.TH (makeLensesFor)
import qualified Graphics.Vty as Vty
import Optics.State.Operators ((%=), (.=))
import Optics.Optic ((%))
import Optics.State (use)
import GHCup.Types (KeyCombination)
import Optics (Lens', to, lens)
import Optics.Operators ( (^.), (.~) )
import Data.Foldable (foldl')
-- | Just some type synonym to make things explicit
type Formatter n = Bool -> Widget n -> Widget n
-- | A label
type Label = T.Text
-- | A help message of an entry
type HelpMessage = T.Text
-- | A button name
type ButtonName n = n
idFormatter :: Formatter n
idFormatter = const id
-- | An error message
type ErrorMessage = T.Text
data ErrorStatus = Valid | Invalid ErrorMessage
-- | A lens which does nothing. Usefull to defined no-op fields
emptyLens :: Lens' s ()
emptyLens = lens (const ()) (\s _ -> s)
-- | A FieldInput is a pair label-content
-- a - is the type of the field it manipulates
-- b - is its internal state (modified in the gui)
-- n - your application's resource name type
data FieldInput a b n =
FieldInput
{ inputState :: b -- ^ The state of the input field (what's rendered in the screen)
, inputValidator :: b -> Either ErrorMessage a -- ^ A validator function
, inputHelp :: HelpMessage -- ^ The input helpMessage
, inputRender :: Bool
-> ErrorStatus
-> HelpMessage
-> b
-> (Widget n -> Widget n)
-> Widget n -- ^ How to draw the input, with focus a help message and input.
-- A extension function can be applied too
, inputHandler :: BrickEvent n () -> EventM n b () -- ^ The handler
}
makeLensesFor
[ ("inputState", "inputStateL")
, ("inputValidator", "inputValidatorL")
, ("inputName", "inputNameL")
, ("inputHelp", "inputHelpL")
]
''FieldInput
-- | The MenuField is an existential type which stores a Lens' to a part of the Menu state.
-- In also contains a Field input which internal state is hidden
data MenuField s n where
MenuField ::
{ fieldAccesor :: Lens' s a -- ^ A Lens pointing to some part of the state
, fieldInput :: FieldInput a b n -- ^ The input which modifies the state
, fieldLabel :: Label -- ^ The label
, fieldStatus :: ErrorStatus -- ^ Whether the current is valid or not.
, fieldName :: n
} -> MenuField s n
makeLensesFor
[ ("fieldLabel", "fieldLabelL")
, ("fieldStatus", "fieldStatusL")
]
''MenuField
-- | A fancy lens to the help message
fieldHelpMsgL :: Lens' (MenuField s n) HelpMessage
fieldHelpMsgL = lens g s
where g (MenuField {..})= fieldInput ^. inputHelpL
s (MenuField{..}) msg = MenuField {fieldInput = fieldInput & inputHelpL .~ msg , ..}
instance Brick.Named (MenuField s n) n where
getName :: MenuField s n -> n
getName entry = entry & fieldName
{- *****************
CheckBox widget
***************** -}
type CheckBoxField = MenuField
createCheckBoxInput :: FieldInput Bool Bool n
createCheckBoxInput = FieldInput False Right "" checkBoxRender checkBoxHandler
where
border = Border.border . Brick.padRight (Brick.Pad 1) . Brick.padLeft (Brick.Pad 2)
drawBool b =
if b
then border . Brick.withAttr Attributes.installedAttr $ Brick.str Common.installedSign
else border . Brick.withAttr Attributes.notInstalledAttr $ Brick.str Common.notInstalledSign
checkBoxRender focus _ help check f =
let core = f $ drawBool check
in if focus
then core
else core <+> (Brick.padLeft (Brick.Pad 1) . centerV . renderAsHelpMsg $ help)
checkBoxHandler = \case
VtyEvent (Vty.EvKey Vty.KEnter []) -> Brick.modify not
_ -> pure ()
createCheckBoxField :: n -> Lens' s Bool -> CheckBoxField s n
createCheckBoxField name access = MenuField access createCheckBoxInput "" Valid name
{- *****************
Editable widget
***************** -}
type EditableField = MenuField
createEditableInput :: (Ord n, Show n) => n -> (T.Text -> Either ErrorMessage a) -> FieldInput a (Edit.Editor T.Text n) n
createEditableInput name validator = FieldInput initEdit validateEditContent "" drawEdit Edit.handleEditorEvent
where
drawEdit focus errMsg help edi amp =
let
borderBox = amp . Border.border . Brick.padRight Brick.Max
editorRender = Edit.renderEditor (Brick.txt . T.unlines) focus edi
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isEditorEmpty = Edit.getEditContents edi == [mempty]
in case errMsg of
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Valid | isEditorEmpty -> borderBox $ renderAsHelpMsg help
| otherwise -> borderBox editorRender
Invalid msg
| focus && isEditorEmpty -> borderBox $ renderAsHelpMsg help
| focus -> borderBox editorRender
| otherwise -> borderBox $ renderAsErrMsg msg
validateEditContent = validator . T.unlines . Edit.getEditContents
initEdit = Edit.editorText name (Just 1) ""
createEditableField :: (Eq n, Ord n, Show n) => n -> (T.Text -> Either ErrorMessage a) -> Lens' s a -> EditableField s n
createEditableField name validator access = MenuField access input "" Valid name
where
input = createEditableInput name validator
{- *****************
Button widget
***************** -}
type Button = MenuField
createButtonInput :: FieldInput () () n
createButtonInput = FieldInput () Right "" drawButton (const $ pure ())
where drawButton _ _ help _ amp = amp . centerV . renderAsHelpMsg $ help
createButtonField :: n -> Button s n
createButtonField = MenuField emptyLens createButtonInput "" Valid
{- *****************
Utilities
***************** -}
-- | highlights a widget (using List.listSelectedFocusedAttr)
highlighted :: Widget n -> Widget n
highlighted = Brick.withAttr L.listSelectedFocusedAttr
-- | Given a text, crates a highlighted label on focus. An amplifier can be passed
renderAslabel :: T.Text -> Bool -> Widget n
renderAslabel t focus =
if focus
then highlighted $ Brick.txt t
else Brick.txt t
-- | Creates a left align column.
-- Example: |- col2 is align dispite the length of col1
-- row1_col1 row1_col2
-- row2_col1_large row2_col2
leftify :: Int -> Brick.Widget n -> Brick.Widget n
leftify i = Brick.hLimit i . Brick.padRight Brick.Max
-- | center a line in three rows.
centerV :: Widget n -> Widget n
centerV = Brick.padTopBottom 1
-- | render some Text using helpMsgAttr
renderAsHelpMsg :: T.Text -> Widget n
renderAsHelpMsg = Brick.withAttr Attributes.helpMsgAttr . Brick.txt
-- | render some Text using errMsgAttr
renderAsErrMsg :: T.Text -> Widget n
renderAsErrMsg = Brick.withAttr Attributes.errMsgAttr . Brick.txt
{- *****************
Menu widget
***************** -}
-- | A menu is a list of Fields and a state. Informally we can think about s in terms of the record type returned by
-- a form.
data Menu s n
= Menu
{ menuFields :: [MenuField s n] -- ^ The datatype representing the list of entries. Precisely, any array-like data type is highly unconvinient.
, menuState :: s
, menuButtons :: [Button s n] -- ^ The buttons. Commonly, the handlers for buttons are defined outside the menu handler.
, menuFocusRing :: FocusRing n -- ^ The focus ring with the resource name for each entry and each button, in the order you want to loop them.
, menuExitKey :: KeyCombination -- ^ The key to exit the Menu
, menuName :: n -- ^ The resource Name.
}
makeLensesFor
[ ("menuFields", "menuFieldsL"), ("menuState", "menuStateL")
, ("menuButtons", "menuButtonsL"), ("menuFocusRing", "menuFocusRingL")
, ("menuExitKey", "menuExitKeyL"), ("menuName", "menuNameL")
]
''Menu
createMenu :: n -> s -> KeyCombination -> [Button s n] -> [MenuField s n] -> Menu s n
createMenu n initial exitK buttons fields = Menu fields initial buttons ring exitK n
where ring = F.focusRing $ [field & fieldName | field <- fields] ++ [button & fieldName | button <- buttons]
handlerMenu :: forall n e s. Eq n => BrickEvent n e -> EventM n (Menu s n) ()
handlerMenu ev =
case ev of
VtyEvent (Vty.EvKey (Vty.KChar '\t') []) -> menuFocusRingL %= F.focusNext
VtyEvent (Vty.EvKey Vty.KBackTab []) -> menuFocusRingL %= F.focusPrev
VtyEvent (Vty.EvKey Vty.KDown []) -> menuFocusRingL %= F.focusNext
VtyEvent (Vty.EvKey Vty.KUp []) -> menuFocusRingL %= F.focusPrev
VtyEvent e -> do
focused <- use $ menuFocusRingL % to F.focusGetCurrent
fields <- use menuFieldsL
case focused of
Nothing -> pure ()
Just n -> do
updated_fields <- updateFields n (VtyEvent e) fields
menuFieldsL .= updated_fields
_ -> pure ()
where
updateFields :: n -> BrickEvent n () -> [MenuField s n] -> EventM n (Menu s n) [MenuField s n]
updateFields n e [] = pure []
updateFields n e (x@(MenuField {fieldInput = i@(FieldInput {..}) , ..}):xs) =
if Brick.getName x == n
then do
newb <- Brick.nestEventM' inputState (inputHandler e)
let newField = MenuField {fieldInput = (FieldInput {inputState=newb, ..}) , ..}
case inputValidator newb of
Left errmsg -> pure $ (newField & fieldStatusL .~ Invalid errmsg):xs
Right a -> menuStateL % fieldAccesor .= a >> pure ((newField & fieldStatusL .~ Valid):xs)
else fmap (x:) (updateFields n e xs)
drawMenu :: (Eq n, Ord n, Show n, Brick.Named (MenuField s n) n) => Menu s n -> Widget n
drawMenu menu =
Brick.vBox
[ Brick.vBox buttonWidgets
, Common.separator
, Brick.withVScrollBars Brick.OnRight
$ Brick.viewport (menu ^. menuNameL) Brick.Vertical
$ Brick.vBox fieldWidgets
, Brick.txt " "
, Brick.padRight Brick.Max $
Brick.txt "Press "
<+> Common.keyToWidget (menu ^. menuExitKeyL)
<+> Brick.txt " to go back"
]
where
drawField amp focus (MenuField { fieldInput = FieldInput {..}, ..}) =
let input = inputRender focus fieldStatus inputHelp inputState (amp focus)
in if focus
then Brick.visible input
else input
fieldLabels = [field & fieldLabel | field <- menu ^. menuFieldsL]
buttonLabels = [button & fieldLabel | button <- menu ^. menuButtonsL]
allLabels = fieldLabels ++ buttonLabels
maxWidth = foldl' max 5 (fmap Brick.textWidth allLabels)
-- A list of functions which draw a highlighted label with right padding at the left of a widget.
amplifiers =
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let labelsWidgets = fmap renderAslabel fieldLabels
in fmap (\f b -> ((centerV . leftify (maxWidth + 10) $ f b) <+>) ) labelsWidgets
drawFields = fmap drawField amplifiers
fieldWidgets = zipWith (F.withFocusRing (menu ^. menuFocusRingL)) drawFields (menu ^. menuFieldsL)
buttonAmplifiers =
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let buttonAsWidgets = fmap renderAslabel buttonLabels
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in fmap (\f b -> ((leftify (maxWidth + 10) . Border.border $ f b) <+>) ) buttonAsWidgets
drawButtons = fmap drawField buttonAmplifiers
buttonWidgets = zipWith (F.withFocusRing (menu ^. menuFocusRingL)) drawButtons (menu ^. menuButtonsL)