This module is part of Chatty.
  Copyleft (c) 2014 Marvin Cohrs

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  Please share Antisplice with everyone you like.

  Chatty is free software: you can redistribute it and/or modify
  it under the terms of the GNU Affero General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  Chatty is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  GNU Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License
  along with Chatty. If not, see <http://www.gnu.org/licenses/>.

-- | Provides an 'ExtendedPrinter' that handles colours using HTML output.
module Text.Chatty.Extended.HTML where

import Text.Chatty.Printer
import Text.Chatty.Expansion
import Text.Chatty.Extended.Printer
import Control.Monad
import Control.Monad.Trans.Class
import Control.Monad.IO.Class

-- | An 'ExtendedPrinter' for HTML output.
newtype HtmlPrinterT m a = HtmlPrinter { runHtmlPrinterT :: m a }

instance Monad m => Monad (HtmlPrinterT m) where
  return = HtmlPrinter . return
  (HtmlPrinter p) >>= f = HtmlPrinter $ do p' <- p; runHtmlPrinterT (f p')

instance MonadTrans HtmlPrinterT where
  lift = HtmlPrinter

instance Functor m => Functor (HtmlPrinterT m) where
  fmap f (HtmlPrinter p) = HtmlPrinter $ fmap f p

instance MonadIO m => MonadIO (HtmlPrinterT m) where
  liftIO = lift . liftIO

instance MonadPrinter m => MonadPrinter (HtmlPrinterT m) where
  mprint = lift . mprint . concatMap maskHtml
  mnoecho = lift . mnoecho . concatMap maskHtml
  mflush = lift mflush
  mnomask = lift . mnomask

instance MonadPrinter m => ExtendedPrinter (HtmlPrinterT m) where
  estart c =  lift $ mprint $ concat ["<span style=\"color: #", hexColour c, ";\">"]
  efin = lift $ mprint "</span>"

instance (Functor m,MonadExpand m) => MonadExpand (HtmlPrinterT m) where
  expand = lift . expand <=< liftM (replay.snd) . runRecorderT . runHtmlPrinterT . expandClr

-- | Convert the given character to its HTML representation.
maskHtml :: Char -> String
maskHtml '&' = "&amp;"
maskHtml '<' = "&lt;"
maskHtml '>' = "&gt;"
--maskHtml ' ' = "&nbsp;"
maskHtml c = [c]

-- | Convert the given colour to its CSS representation.
hexColour (Dull Green) = "007F00"
hexColour (Vivid Green) = "00FF00"
hexColour (Dull Red) = "7F0000"
hexColour (Vivid Red) = "FF0000"
hexColour (Dull Yellow) = "7F7F00"
hexColour (Vivid Yellow) = "FFFF00"
hexColour (Dull Blue) = "00007F"
hexColour (Vivid Blue) = "0000FF"
hexColour (Dull Black) = "000000"
hexColour (Vivid Black) = "606060"
hexColour (Dull White) = "909090"
hexColour (Vivid White) = "FFFFFF"
hexColour (Dull Cyan) = "007F7F"
hexColour (Vivid Cyan) = "00FFFF"
hexColour (Dull Magenta) = "7F007F"
hexColour (Vivid Magenta) = "FF00FF"