{-# LANGUAGE CPP               #-}
{-# LANGUAGE LambdaCase        #-}
{-# LANGUAGE OverloadedStrings #-}

#include "version-compatibility-macros.h"

-- | __Warning:__ Internal module. May change arbitrarily between versions.
module Data.Text.Prettyprint.Doc.Render.Terminal.Internal where



import           Control.Applicative
import           Data.Maybe
import           Data.Semigroup
import           Data.Text              (Text)
import qualified Data.Text              as T
import qualified Data.Text.Lazy         as TL
import qualified Data.Text.Lazy.Builder as TLB
import qualified Data.Text.Lazy.IO      as TL
import qualified System.Console.ANSI    as ANSI
import           System.IO              (Handle, stdout)

import Data.Text.Prettyprint.Doc
import Data.Text.Prettyprint.Doc.Render.Util.Panic
import Data.Text.Prettyprint.Doc.Render.Util.StackMachine

#if !(APPLICATIVE_MONAD)
import Control.Applicative
#endif



-- $setup
--
-- (Definitions for the doctests)
--
-- >>> :set -XOverloadedStrings
-- >>> import qualified Data.Text.Lazy.IO as TL
-- >>> import qualified Data.Text.Lazy as TL
-- >>> import Data.Text.Prettyprint.Doc.Render.Terminal



-- | The 8 ANSI terminal colors.
data Color = Black | Red | Green | Yellow | Blue | Magenta | Cyan | White
    deriving (Eq, Ord, Show)

-- | Dull or vivid coloring, as supported by ANSI terminals.
data Intensity = Vivid | Dull
    deriving (Eq, Ord, Show)

-- | Foreground (text) or background (paper) color
data Layer = Foreground | Background
    deriving (Eq, Ord, Show)

data Bold       = Bold       deriving (Eq, Ord, Show)
data Underlined = Underlined deriving (Eq, Ord, Show)
data Italicized = Italicized deriving (Eq, Ord, Show)

-- | Style the foreground with a vivid color.
color :: Color -> AnsiStyle
color c = mempty { ansiForeground = Just (Vivid, c) }

-- | Style the background with a vivid color.
bgColor :: Color -> AnsiStyle
bgColor c =  mempty { ansiBackground = Just (Vivid, c) }

-- | Style the foreground with a dull color.
colorDull :: Color -> AnsiStyle
colorDull c =  mempty { ansiForeground = Just (Dull, c) }

-- | Style the background with a dull color.
bgColorDull :: Color -> AnsiStyle
bgColorDull c =  mempty { ansiBackground = Just (Dull, c) }

-- | Render in __bold__.
bold :: AnsiStyle
bold = mempty { ansiBold = Just Bold }

-- | Render in /italics/.
italicized :: AnsiStyle
italicized = mempty { ansiItalics = Just Italicized }

-- | Render underlined.
underlined :: AnsiStyle
underlined = mempty { ansiUnderlining = Just Underlined }



-- | @('renderLazy' doc)@ takes the output @doc@ from a rendering function
-- and transforms it to lazy text, including ANSI styling directives for things
-- like colorization.
--
-- ANSI color information will be discarded by this function unless you are
-- running on a Unix-like operating system. This is due to a technical
-- limitation in Windows ANSI support.
--
-- With a bit of trickery to make the ANSI codes printable, here is an example
-- that would render colored in an ANSI terminal:
--
-- >>> let render = TL.putStrLn . TL.replace "\ESC" "\\e" . renderLazy . layoutPretty defaultLayoutOptions
-- >>> let doc = annotate (color Red) ("red" <+> align (vsep [annotate (color Blue <> underlined) ("blue+u" <+> annotate bold "bold" <+> "blue+u"), "red"]))
-- >>> render (unAnnotate doc)
-- red blue+u bold blue+u
--     red
-- >>> render doc
-- \e[0;91mred \e[0;94;4mblue+u \e[0;94;1;4mbold\e[0;94;4m blue+u\e[0;91m
--     red\e[0m
--
-- Run the above via @echo -e '...'@ in your terminal to see the coloring.
renderLazy :: SimpleDocStream AnsiStyle -> TL.Text
renderLazy doc
  = let (resultBuilder, remainingStyles) = execStackMachine [mempty] (build doc)
    in case remainingStyles of
        [] -> error ("There is no empty style left at the end of rendering" ++
                     " (but there should be). Please report this as a bug.")
        [_] -> TLB.toLazyText resultBuilder
        xs -> error ("There are " <> show (length xs) <> " styles left at the" ++
                     "end of rendering (there should be only 1). Please report" ++
                     " this as a bug.")

build :: SimpleDocStream AnsiStyle -> StackMachine TLB.Builder AnsiStyle ()
build = \case
    SFail -> panicUncaughtFail
    SEmpty -> pure ()
    SChar c x -> do
        writeOutput (TLB.singleton c)
        build x
    SText _l t x -> do
        writeOutput (TLB.fromText t)
        build x
    SLine i x -> do
        writeOutput (TLB.singleton '\n')
        writeOutput (TLB.fromText (T.replicate i " "))
        build x
    SAnnPush s x -> do
        currentStyle <- unsafePeekStyle
        let newStyle = s <> currentStyle
        writeOutput (styleToRaw newStyle)
        pushStyle newStyle
        build x
    SAnnPop x -> do
        _currentStyle <- unsafePopStyle
        newStyle <- unsafePeekStyle
        writeOutput (styleToRaw newStyle)
        build x

-- | Begin rendering in a certain style. Instead of using this type directly,
-- consider using the 'Semigroup' instance to create new styles out of the smart
-- constructors, such as
--
-- @
-- style = 'color' 'Green' '<>' 'bold'
-- styledDoc = 'annotate' style "hello world"
-- @
data AnsiStyle = SetAnsiStyle
    { ansiForeground  :: Maybe (Intensity, Color) -- ^ Set the foreground color, or keep the old one.
    , ansiBackground  :: Maybe (Intensity, Color) -- ^ Set the background color, or keep the old one.
    , ansiBold        :: Maybe Bold               -- ^ Switch on boldness, or don’t do anything.
    , ansiItalics     :: Maybe Italicized         -- ^ Switch on italics, or don’t do anything.
    , ansiUnderlining :: Maybe Underlined         -- ^ Switch on underlining, or don’t do anything.
    } deriving (Eq, Ord, Show)

-- | Keep the first decision for each of foreground color, background color,
-- boldness, italication, and underlining.
--
-- Example:
--
-- @
-- 'color' 'Red' '<>' 'color' 'Green'
-- @
--
-- is red.
instance Semigroup AnsiStyle where
    cs1 <> cs2 = SetAnsiStyle
        { ansiForeground  = ansiForeground  cs1 <|> ansiForeground  cs2
        , ansiBackground  = ansiBackground  cs1 <|> ansiBackground  cs2
        , ansiBold        = ansiBold        cs1 <|> ansiBold        cs2
        , ansiItalics     = ansiItalics     cs1 <|> ansiItalics     cs2
        , ansiUnderlining = ansiUnderlining cs1 <|> ansiUnderlining cs2 }

instance Monoid AnsiStyle where
    mempty = SetAnsiStyle Nothing Nothing Nothing Nothing Nothing
    mappend = (<>)

styleToRaw :: AnsiStyle -> TLB.Builder
styleToRaw = TLB.fromString . ANSI.setSGRCode . stylesToSgrs
  where
    stylesToSgrs :: AnsiStyle -> [ANSI.SGR]
    stylesToSgrs (SetAnsiStyle fg bg b i u) = catMaybes
        [ Just ANSI.Reset
        , fmap (\(intensity, c) -> ANSI.SetColor ANSI.Foreground (convertIntensity intensity) (convertColor c)) fg
        , fmap (\(intensity, c) -> ANSI.SetColor ANSI.Background (convertIntensity intensity) (convertColor c)) bg
        , fmap (\_              -> ANSI.SetConsoleIntensity ANSI.BoldIntensity) b
        , fmap (\_              -> ANSI.SetItalicized True) i
        , fmap (\_              -> ANSI.SetUnderlining ANSI.SingleUnderline) u
        ]

    convertIntensity :: Intensity -> ANSI.ColorIntensity
    convertIntensity = \case
        Vivid -> ANSI.Vivid
        Dull  -> ANSI.Dull

    convertColor :: Color -> ANSI.Color
    convertColor = \case
        Black   -> ANSI.Black
        Red     -> ANSI.Red
        Green   -> ANSI.Green
        Yellow  -> ANSI.Yellow
        Blue    -> ANSI.Blue
        Magenta -> ANSI.Magenta
        Cyan    -> ANSI.Cyan
        White   -> ANSI.White



-- | @('renderStrict' sdoc)@ takes the output @sdoc@ from a rendering and
-- transforms it to strict text.
renderStrict :: SimpleDocStream AnsiStyle -> Text
renderStrict = TL.toStrict . renderLazy

-- | @('renderIO' h sdoc)@ writes @sdoc@ to the file @h@.
--
-- >>> renderIO System.IO.stdout (layoutPretty defaultLayoutOptions "hello\nworld")
-- hello
-- world
renderIO :: Handle -> SimpleDocStream AnsiStyle -> IO ()
renderIO h sdoc = TL.hPutStrLn h (renderLazy sdoc)

-- | @('putDoc' doc)@ prettyprints document @doc@ to standard output using
-- 'defaultLayoutOptions'.
--
-- >>> putDoc ("hello" <+> "world")
-- hello world
--
-- @
-- 'putDoc' = 'hPutDoc' 'stdout'
-- @
putDoc :: Doc AnsiStyle -> IO ()
putDoc = hPutDoc stdout

-- | Like 'putDoc', but instead of using 'stdout', print to a user-provided
-- handle, e.g. a file or a socket using 'defaultLayoutOptions'.
--
-- > main = withFile "someFile.txt" (\h -> hPutDoc h (vcat ["vertical", "text"]))
--
-- @
-- 'hPutDoc' h doc = 'renderIO' h ('layoutPretty' 'defaultLayoutOptions' doc)
-- @
hPutDoc :: Handle -> Doc AnsiStyle -> IO ()
hPutDoc h doc = renderIO h (layoutPretty defaultLayoutOptions doc)