shrub/pkg/hs/urbit-king/lib/Urbit/Vere/Term/Logic.hs
2020-10-05 13:26:46 -04:00

160 lines
4.2 KiB
Haskell

{-|
Tracks terminal state so that new terminal connections can be brought
up to speed.
-}
module Urbit.Vere.Term.Logic
( SpinnerCause(..), St, Ev(..), Ef(..)
, init
, step
, drawState
, fromTermEv
, toTermEv
) where
import Urbit.Prelude hiding (init)
import Data.Sequence (Seq((:<|)))
import qualified Urbit.Arvo as Arvo
import qualified Urbit.Vere.Term.API as Term
--------------------------------------------------------------------------------
data SpinnerCause = User | Event Text
deriving (Show)
type SpinnerState = Maybe SpinnerCause
{-|
%line -- Output a line above the edit line.
%spin -- Set the spinner state.
%bell -- Ring a bell (no change to the state).
%draw -- Redraw the current line (no change to the state).
%move -- Move the cursor position.
%edit -- Set the edit line, moving the cursor to the end.
%more -- Write the edit line to history, and clear it.
-}
data Ev
= EvLine Text
| EvSlog (Atom, Tank)
| EvSpin SpinnerState
| EvMove Word
| EvBell
| EvDraw
| EvEdit Text
| EvMore
deriving (Show)
data Ef
= EfClear
| EfWrite Text
| EfShift Int
| EfRing
| EfSpin SpinnerState
deriving (Show)
data History
= HistoryText !Text
| HistorySlog !(Atom, Tank)
deriving (Show)
data St = St
{ sHistory :: !(Seq History)
, sLine :: !Text
, sCurPos :: !Word
, sSpinner :: !SpinnerState
}
deriving (Show)
--------------------------------------------------------------------------------
init :: St
init = St mempty "" 0 Nothing
{-|
When we process `EvMore`, we need to append a newline to the end of
the current line. During normal play, the ENTER key inserts the
newline for us, so we need to recreate that newline when we rebuild
the state for a new terminal connection.
-}
step :: St -> Ev -> St
step st@St{..} = \case
EvLine t -> st & recordText t
EvSlog s -> st & recordSlog s
EvSpin s -> st { sSpinner = s }
EvMove w -> st { sCurPos = min w (word $ length sLine) }
EvEdit t -> st { sLine = t, sCurPos = word (length t) }
EvMore -> st { sLine = "", sCurPos = 0 } & recordText (sLine <> "\n")
EvBell -> st
EvDraw -> st
where
word :: Integral i => i -> Word
word = fromIntegral
recordText :: Text -> St -> St
recordText !t st@St{..} = st {
sHistory = trim (sHistory |> (HistoryText t))
}
recordSlog :: (Atom, Tank) -> St -> St
recordSlog !t st@St{..} = st {
sHistory = trim (sHistory |> (HistorySlog t))
}
trim :: Seq a -> Seq a
trim s | length s < 20 = s
trim (_ :<| s) = s
trim s = s
drawState :: St -> [Ev]
drawState St{..} = hist <> out <> cur <> spin
where
hist = drawHistory <$> toList sHistory
out = if null sLine then [] else [EvEdit sLine]
cur = if 0 == sCurPos then [] else [EvMove $ fromIntegral $ sCurPos]
spin = maybe [] (singleton . EvSpin . Just) sSpinner
drawHistory (HistoryText t) = EvLine t
drawHistory (HistorySlog s) = EvSlog s
-- Conversion ------------------------------------------------------------------
fromBlit :: Arvo.Blit -> Maybe Ev
fromBlit = \case
Arvo.Hop w -> Just $ EvMove $ fromIntegral w
Arvo.Bel () -> Just EvBell
Arvo.Clr () -> Just EvDraw
Arvo.Lin s -> Just $ EvEdit (pack s)
Arvo.Mor () -> Just EvMore
_ -> Nothing
toCause :: Maybe Cord -> SpinnerCause
toCause Nothing = User
toCause (Just (Cord c)) = Event c
fromCause :: SpinnerCause -> Maybe Cord
fromCause User = Nothing
fromCause (Event t) = Just (Cord t)
fromTermEv :: Term.Ev -> [Ev]
fromTermEv = \case
Term.Blits bs -> catMaybes (fromBlit <$> bs)
Term.Trace t -> [EvLine $ unCord t]
Term.Blank -> [EvLine ""]
Term.Spinr s -> [EvSpin $ toCause <$> s]
Term.Slog s -> [EvSlog s]
toTermEv :: Ev -> Term.Ev
toTermEv = \case
EvLine "" -> Term.Blank
EvLine t -> Term.Trace (Cord t)
EvSlog s -> Term.Slog s
EvSpin s -> Term.Spinr (fromCause <$> s)
EvMove w -> Term.Blits [Arvo.Hop $ fromIntegral w]
EvBell -> Term.Blits [Arvo.Bel ()]
EvDraw -> Term.Blits [Arvo.Clr ()]
EvEdit t -> Term.Blits [Arvo.Lin $ unpack t]
EvMore -> Term.Blits [Arvo.Mor ()]