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module Terminal (
TerminalOutput,
TerminalLine,
TerminalFootnote(..),
initTerminalOutput,
newLine,
redrawLine,
newFootnote,
terminalHandle,
terminalBlinkStatus,
) where
import Control.Concurrent
import Control.Concurrent.STM
import Control.Monad
import Data.Function
import Data.Text (Text)
import Data.Text qualified as T
import Data.Text.IO qualified as T
import System.IO
data TerminalOutput = TerminalOutput
{ outHandle :: Handle
, outNumLines :: MVar Int
, outNextFootnote :: MVar Int
, outBlinkVar :: TVar Bool
}
instance Eq TerminalOutput where
(==) = (==) `on` outNumLines
data TerminalLine = TerminalLine
{ lineOutput :: TerminalOutput
, lineNum :: Int
}
deriving (Eq)
data TerminalFootnote = TerminalFootnote
{ tfLine :: TerminalLine
, tfNumber :: Int
}
deriving (Eq)
initTerminalOutput :: IO TerminalOutput
initTerminalOutput = do
outHandle <- return stdout
outNumLines <- newMVar 0
outNextFootnote <- newMVar 1
outBlinkVar <- newTVarIO False
void $ forkIO $ forever $ do
threadDelay 500000
atomically $ writeTVar outBlinkVar . not =<< readTVar outBlinkVar
return TerminalOutput {..}
newLine :: TerminalOutput -> Text -> IO TerminalLine
newLine lineOutput@TerminalOutput {..} text = do
modifyMVar outNumLines $ \lineNum -> do
T.putStrLn text
hFlush outHandle
return ( lineNum + 1, TerminalLine {..} )
redrawLine :: TerminalLine -> Text -> IO ()
redrawLine TerminalLine {..} text = do
let TerminalOutput {..} = lineOutput
withMVar outNumLines $ \total -> do
let moveBy = total - lineNum
T.putStr $ "\ESC[s\ESC[" <> T.pack (show moveBy) <> "F" <> text <> "\ESC[u"
hFlush outHandle
newFootnote :: TerminalOutput -> Text -> IO TerminalFootnote
newFootnote tout@TerminalOutput {..} text = do
modifyMVar outNextFootnote $ \tfNumber -> do
tfLine <- newLine tout $ "[" <> T.pack (show tfNumber) <> "] " <> text
hFlush outHandle
return ( tfNumber + 1, TerminalFootnote {..} )
terminalHandle :: TerminalOutput -> Handle
terminalHandle = outHandle
terminalBlinkStatus :: TerminalOutput -> STM Bool
terminalBlinkStatus TerminalOutput {..} = readTVar outBlinkVar
|