{-# LANGUAGE NoImplicitPrelude #-}
{- |
   Module      : Text.Pandoc.Writers.Textile
   Copyright   : Copyright (C) 2010-2019 John MacFarlane
   License     : GNU GPL, version 2 or above

   Maintainer  : John MacFarlane <jgm@berkeley.edu>
   Stability   : alpha
   Portability : portable

Conversion of 'Pandoc' documents to Textile markup.

Textile:  <http://thresholdstate.com/articles/4312/the-textile-reference-manual>
-}
module Text.Pandoc.Writers.Textile ( writeTextile ) where
import Prelude
import Control.Monad.State.Strict
import Data.Char (isSpace)
import Data.List (intercalate)
import Data.Text (Text, pack)
import Text.Pandoc.Class (PandocMonad, report)
import Text.Pandoc.Definition
import Text.Pandoc.ImageSize
import Text.Pandoc.Logging
import Text.Pandoc.Options
import Text.DocLayout (render, literal)
import Text.Pandoc.Shared
import Text.Pandoc.Templates (renderTemplate)
import Text.Pandoc.Writers.Shared
import Text.Pandoc.XML (escapeStringForXML)

data WriterState = WriterState {
    stNotes     :: [String]        -- Footnotes
  , stListLevel :: [Char]          -- String at beginning of list items, e.g. "**"
  , stStartNum  :: Maybe Int       -- Start number if first list item
  , stUseTags   :: Bool            -- True if we should use HTML tags because we're in a complex list
  }

type TW = StateT WriterState

-- | Convert Pandoc to Textile.
writeTextile :: PandocMonad m => WriterOptions -> Pandoc -> m Text
writeTextile opts document =
  evalStateT (pandocToTextile opts document)
            WriterState { stNotes = [],
                          stListLevel = [],
                          stStartNum = Nothing,
                          stUseTags = False }

-- | Return Textile representation of document.
pandocToTextile :: PandocMonad m
                => WriterOptions -> Pandoc -> TW m Text
pandocToTextile opts (Pandoc meta blocks) = do
  metadata <- metaToContext opts
                 (fmap (literal . pack) . blockListToTextile opts)
                 (fmap (literal . pack) . inlineListToTextile opts) meta
  body <- blockListToTextile opts blocks
  notes <- gets $ unlines . reverse . stNotes
  let main = pack $ body ++ if null notes then "" else "\n\n" ++ notes
  let context = defField "body" main metadata
  return $
    case writerTemplate opts of
         Nothing  -> main
         Just tpl -> render Nothing $ renderTemplate tpl context

withUseTags :: PandocMonad m => TW m a -> TW m a
withUseTags action = do
  oldUseTags <- gets stUseTags
  modify $ \s -> s { stUseTags = True }
  result <- action
  modify $ \s -> s { stUseTags = oldUseTags }
  return result

-- | Escape one character as needed for Textile.
escapeCharForTextile :: Char -> String
escapeCharForTextile x = case x of
                         '&'      -> "&amp;"
                         '<'      -> "&lt;"
                         '>'      -> "&gt;"
                         '"'      -> "&quot;"
                         '*'      -> "&#42;"
                         '_'      -> "&#95;"
                         '@'      -> "&#64;"
                         '+'      -> "&#43;"
                         '-'      -> "&#45;"
                         '|'      -> "&#124;"
                         '\x2014' -> " -- "
                         '\x2013' -> " - "
                         '\x2019' -> "'"
                         '\x2026' -> "..."
                         c        -> [c]

-- | Escape string as needed for Textile.
escapeStringForTextile :: String -> String
escapeStringForTextile = concatMap escapeCharForTextile

-- | Convert Pandoc block element to Textile.
blockToTextile :: PandocMonad m
               => WriterOptions -- ^ Options
               -> Block         -- ^ Block element
               -> TW m String

blockToTextile _ Null = return ""

blockToTextile opts (Div attr bs) = do
  let startTag = render Nothing $ tagWithAttrs "div" attr
  let endTag = "</div>"
  contents <- blockListToTextile opts bs
  return $ startTag ++ "\n\n" ++ contents ++ "\n\n" ++ endTag ++ "\n"

blockToTextile opts (Plain inlines) =
  inlineListToTextile opts inlines

-- title beginning with fig: indicates that the image is a figure
blockToTextile opts (Para [Image attr txt (src,'f':'i':'g':':':tit)]) = do
  capt <- blockToTextile opts (Para txt)
  im <- inlineToTextile opts (Image attr txt (src,tit))
  return $ im ++ "\n" ++ capt

blockToTextile opts (Para inlines) = do
  useTags <- gets stUseTags
  listLevel <- gets stListLevel
  contents <- inlineListToTextile opts inlines
  return $ if useTags
              then "<p>" ++ contents ++ "</p>"
              else contents ++ if null listLevel then "\n" else ""

blockToTextile opts (LineBlock lns) =
  blockToTextile opts $ linesToPara lns

blockToTextile _ b@(RawBlock f str)
  | f == Format "html" || f == Format "textile" = return str
  | otherwise                                   = do
      report $ BlockNotRendered b
      return ""

blockToTextile _ HorizontalRule = return "<hr />\n"

blockToTextile opts (Header level (ident,classes,keyvals) inlines) = do
  contents <- inlineListToTextile opts inlines
  let identAttr = if null ident then "" else '#':ident
  let attribs = if null identAttr && null classes
                   then ""
                   else "(" ++ unwords classes ++ identAttr ++ ")"
  let lang = maybe "" (\x -> "[" ++ x ++ "]") $ lookup "lang" keyvals
  let styles = maybe "" (\x -> "{" ++ x ++ "}") $ lookup "style" keyvals
  let prefix = 'h' : show level ++ attribs ++ styles ++ lang ++ ". "
  return $ prefix ++ contents ++ "\n"

blockToTextile _ (CodeBlock (_,classes,_) str) | any (all isSpace) (lines str) =
  return $ "<pre"  ++ classes' ++ ">\n" ++ escapeStringForXML str ++
           "\n</pre>\n"
    where classes' = if null classes
                        then ""
                        else " class=\"" ++ unwords classes ++ "\""

blockToTextile _ (CodeBlock (_,classes,_) str) =
  return $ "bc" ++ classes' ++ ". " ++ str ++ "\n\n"
    where classes' = if null classes
                        then ""
                        else "(" ++ unwords classes ++ ")"

blockToTextile opts (BlockQuote bs@[Para _]) = do
  contents <- blockListToTextile opts bs
  return $ "bq. " ++ contents ++ "\n\n"

blockToTextile opts (BlockQuote blocks) = do
  contents <- blockListToTextile opts blocks
  return $ "<blockquote>\n\n" ++ contents ++ "\n</blockquote>\n"

blockToTextile opts (Table [] aligns widths headers rows') |
         all (==0) widths = do
  hs <- mapM (liftM (("_. " ++) . stripTrailingNewlines) . blockListToTextile opts) headers
  let cellsToRow cells = "|" ++ intercalate "|" cells ++ "|"
  let header = if all null headers then "" else cellsToRow hs ++ "\n"
  let blocksToCell (align, bs) = do
        contents <- stripTrailingNewlines <$> blockListToTextile opts bs
        let alignMarker = case align of
                               AlignLeft    -> "<. "
                               AlignRight   -> ">. "
                               AlignCenter  -> "=. "
                               AlignDefault -> ""
        return $ alignMarker ++ contents
  let rowToCells = mapM blocksToCell . zip aligns
  bs <- mapM rowToCells rows'
  let body = unlines $ map cellsToRow bs
  return $ header ++ body

blockToTextile opts (Table capt aligns widths headers rows') = do
  let alignStrings = map alignmentToString aligns
  captionDoc <- if null capt
                   then return ""
                   else do
                      c <- inlineListToTextile opts capt
                      return $ "<caption>" ++ c ++ "</caption>\n"
  let percent w = show (truncate (100*w) :: Integer) ++ "%"
  let coltags = if all (== 0.0) widths
                   then ""
                   else unlines $ map
                         (\w -> "<col width=\"" ++ percent w ++ "\" />") widths
  head' <- if all null headers
              then return ""
              else do
                 hs <- tableRowToTextile opts alignStrings 0 headers
                 return $ "<thead>\n" ++ hs ++ "\n</thead>\n"
  body' <- zipWithM (tableRowToTextile opts alignStrings) [1..] rows'
  return $ "<table>\n" ++ captionDoc ++ coltags ++ head' ++
            "<tbody>\n" ++ unlines body' ++ "</tbody>\n</table>\n"

blockToTextile opts x@(BulletList items) = do
  oldUseTags <- gets stUseTags
  let useTags = oldUseTags || not (isSimpleList x)
  if useTags
     then do
        contents <- withUseTags $ mapM (listItemToTextile opts) items
        return $ "<ul>\n" ++ vcat contents ++ "\n</ul>\n"
     else do
        modify $ \s -> s { stListLevel = stListLevel s ++ "*" }
        level <- gets $ length . stListLevel
        contents <- mapM (listItemToTextile opts) items
        modify $ \s -> s { stListLevel = init (stListLevel s) }
        return $ vcat contents ++ (if level > 1 then "" else "\n")

blockToTextile opts x@(OrderedList attribs@(start, _, _) items) = do
  oldUseTags <- gets stUseTags
  let useTags = oldUseTags || not (isSimpleList x)
  if useTags
     then do
        contents <- withUseTags $ mapM (listItemToTextile opts) items
        return $ "<ol" ++ listAttribsToString attribs ++ ">\n" ++ vcat contents ++
                   "\n</ol>\n"
     else do
        modify $ \s -> s { stListLevel = stListLevel s ++ "#"
                         , stStartNum = if start > 1
                                           then Just start
                                           else Nothing }
        level <- gets $ length . stListLevel
        contents <- mapM (listItemToTextile opts) items
        modify $ \s -> s { stListLevel = init (stListLevel s),
                           stStartNum = Nothing }
        return $ vcat contents ++ (if level > 1 then "" else "\n")

blockToTextile opts (DefinitionList items) = do
  contents <- withUseTags $ mapM (definitionListItemToTextile opts) items
  return $ "<dl>\n" ++ vcat contents ++ "\n</dl>\n"

-- Auxiliary functions for lists:

-- | Convert ordered list attributes to HTML attribute string
listAttribsToString :: ListAttributes -> String
listAttribsToString (startnum, numstyle, _) =
  let numstyle' = camelCaseToHyphenated $ show numstyle
  in  (if startnum /= 1
          then " start=\"" ++ show startnum ++ "\""
          else "") ++
      (if numstyle /= DefaultStyle
          then " style=\"list-style-type: " ++ numstyle' ++ ";\""
          else "")

-- | Convert bullet or ordered list item (list of blocks) to Textile.
listItemToTextile :: PandocMonad m
                  => WriterOptions -> [Block] -> TW m String
listItemToTextile opts items = do
  contents <- blockListToTextile opts items
  useTags <- gets stUseTags
  if useTags
     then return $ "<li>" ++ contents ++ "</li>"
     else do
       marker <- gets stListLevel
       mbstart <- gets stStartNum
       case mbstart of
            Just n -> do
              modify $ \s -> s{ stStartNum = Nothing }
              return $ marker ++ show n ++ " " ++ contents
            Nothing -> return $ marker ++ " " ++ contents

-- | Convert definition list item (label, list of blocks) to Textile.
definitionListItemToTextile :: PandocMonad m
                            => WriterOptions
                             -> ([Inline],[[Block]])
                             -> TW m String
definitionListItemToTextile opts (label, items) = do
  labelText <- inlineListToTextile opts label
  contents <- mapM (blockListToTextile opts) items
  return $ "<dt>" ++ labelText ++ "</dt>\n" ++
          intercalate "\n" (map (\d -> "<dd>" ++ d ++ "</dd>") contents)

-- | True if the list can be handled by simple wiki markup, False if HTML tags will be needed.
isSimpleList :: Block -> Bool
isSimpleList x =
  case x of
       BulletList items                 -> all isSimpleListItem items
       OrderedList (_, sty, _) items    -> all isSimpleListItem items &&
                                            sty `elem` [DefaultStyle, Decimal]
       _                                -> False

-- | True if list item can be handled with the simple wiki syntax.  False if
--   HTML tags will be needed.
isSimpleListItem :: [Block] -> Bool
isSimpleListItem []  = True
isSimpleListItem [x] =
  case x of
       Plain _         -> True
       Para  _         -> True
       BulletList _    -> isSimpleList x
       OrderedList _ _ -> isSimpleList x
       _               -> False
isSimpleListItem [x, y] | isPlainOrPara x =
  case y of
       BulletList _    -> isSimpleList y
       OrderedList _ _ -> isSimpleList y
       _               -> False
isSimpleListItem _ = False

isPlainOrPara :: Block -> Bool
isPlainOrPara (Plain _) = True
isPlainOrPara (Para  _) = True
isPlainOrPara _         = False

-- | Concatenates strings with line breaks between them.
vcat :: [String] -> String
vcat = intercalate "\n"

-- Auxiliary functions for tables. (TODO: these are common to HTML, MediaWiki,
-- and Textile writers, and should be abstracted out.)

tableRowToTextile :: PandocMonad m
                  => WriterOptions
                  -> [String]
                  -> Int
                  -> [[Block]]
                  -> TW m String
tableRowToTextile opts alignStrings rownum cols' = do
  let celltype = if rownum == 0 then "th" else "td"
  let rowclass = case rownum of
                      0 -> "header"
                      x | x `rem` 2 == 1 -> "odd"
                      _ -> "even"
  cols'' <- zipWithM
            (\alignment item -> tableItemToTextile opts celltype alignment item)
            alignStrings cols'
  return $ "<tr class=\"" ++ rowclass ++ "\">\n" ++ unlines cols'' ++ "</tr>"

alignmentToString :: Alignment -> [Char]
alignmentToString alignment = case alignment of
                                 AlignLeft    -> "left"
                                 AlignRight   -> "right"
                                 AlignCenter  -> "center"
                                 AlignDefault -> "left"

tableItemToTextile :: PandocMonad m
                   => WriterOptions
                   -> String
                   -> String
                   -> [Block]
                   -> TW m String
tableItemToTextile opts celltype align' item = do
  let mkcell x = "<" ++ celltype ++ " align=\"" ++ align' ++ "\">" ++
                    x ++ "</" ++ celltype ++ ">"
  contents <- blockListToTextile opts item
  return $ mkcell contents

-- | Convert list of Pandoc block elements to Textile.
blockListToTextile :: PandocMonad m
                   => WriterOptions -- ^ Options
                   -> [Block]       -- ^ List of block elements
                   -> TW m String
blockListToTextile opts blocks =
  vcat <$> mapM (blockToTextile opts) blocks

-- | Convert list of Pandoc inline elements to Textile.
inlineListToTextile :: PandocMonad m
                    => WriterOptions -> [Inline] -> TW m String
inlineListToTextile opts lst =
  concat <$> mapM (inlineToTextile opts) lst

-- | Convert Pandoc inline element to Textile.
inlineToTextile :: PandocMonad m => WriterOptions -> Inline -> TW m String

inlineToTextile opts (Span _ lst) =
  inlineListToTextile opts lst

inlineToTextile opts (Emph lst) = do
  contents <- inlineListToTextile opts lst
  return $ if '_' `elem` contents
              then "<em>" ++ contents ++ "</em>"
              else "_" ++ contents ++ "_"

inlineToTextile opts (Strong lst) = do
  contents <- inlineListToTextile opts lst
  return $ if '*' `elem` contents
              then "<strong>" ++ contents ++ "</strong>"
              else "*" ++ contents ++ "*"

inlineToTextile opts (Strikeout lst) = do
  contents <- inlineListToTextile opts lst
  return $ if '-' `elem` contents
              then "<del>" ++ contents ++ "</del>"
              else "-" ++ contents ++ "-"

inlineToTextile opts (Superscript lst) = do
  contents <- inlineListToTextile opts lst
  return $ if '^' `elem` contents
              then "<sup>" ++ contents ++ "</sup>"
              else "[^" ++ contents ++ "^]"

inlineToTextile opts (Subscript lst) = do
  contents <- inlineListToTextile opts lst
  return $ if '~' `elem` contents
              then "<sub>" ++ contents ++ "</sub>"
              else "[~" ++ contents ++ "~]"

inlineToTextile opts (SmallCaps lst) = inlineListToTextile opts lst

inlineToTextile opts (Quoted SingleQuote lst) = do
  contents <- inlineListToTextile opts lst
  return $ "'" ++ contents ++ "'"

inlineToTextile opts (Quoted DoubleQuote lst) = do
  contents <- inlineListToTextile opts lst
  return $ "\"" ++ contents ++ "\""

inlineToTextile opts (Cite _  lst) = inlineListToTextile opts lst

inlineToTextile _ (Code _ str) =
  return $ if '@' `elem` str
           then "<tt>" ++ escapeStringForXML str ++ "</tt>"
           else "@" ++ str ++ "@"

inlineToTextile _ (Str str) = return $ escapeStringForTextile str

inlineToTextile _ (Math _ str) =
  return $ "<span class=\"math\">" ++ escapeStringForXML str ++ "</span>"

inlineToTextile opts il@(RawInline f str)
  | f == Format "html" || f == Format "textile" = return str
  | (f == Format "latex" || f == Format "tex") &&
     isEnabled Ext_raw_tex opts                 = return str
  | otherwise                                   = do
      report $ InlineNotRendered il
      return ""

inlineToTextile _ LineBreak = return "\n"

inlineToTextile _ SoftBreak = return " "

inlineToTextile _ Space = return " "

inlineToTextile opts (Link (_, cls, _) txt (src, _)) = do
  label <- case txt of
                [Code _ s]
                 | s == src -> return "$"
                [Str s]
                 | s == src -> return "$"
                _           -> inlineListToTextile opts txt
  let classes = if null cls || cls == ["uri"] && label == "$"
                   then ""
                   else "(" ++ unwords cls ++ ")"
  return $ "\"" ++ classes ++ label ++ "\":" ++ src

inlineToTextile opts (Image attr@(_, cls, _) alt (source, tit)) = do
  alt' <- inlineListToTextile opts alt
  let txt = if null tit
               then if null alt'
                       then ""
                       else "(" ++ alt' ++ ")"
               else "(" ++ tit ++ ")"
      classes = if null cls
                   then ""
                   else "(" ++ unwords cls ++ ")"
      showDim dir = let toCss str = Just $ show dir ++ ":" ++ str ++ ";"
                    in case dimension dir attr of
                         Just (Percent a) -> toCss $ show (Percent a)
                         Just dim         -> toCss $ showInPixel opts dim ++ "px"
                         Nothing          -> Nothing
      styles = case (showDim Width, showDim Height) of
                 (Just w, Just h)   -> "{" ++ w ++ h ++ "}"
                 (Just w, Nothing)  -> "{" ++ w ++ "height:auto;}"
                 (Nothing, Just h)  -> "{" ++ "width:auto;" ++ h ++ "}"
                 (Nothing, Nothing) -> ""
  return $ "!" ++ classes ++ styles ++ source ++ txt ++ "!"

inlineToTextile opts (Note contents) = do
  curNotes <- gets stNotes
  let newnum = length curNotes + 1
  contents' <- blockListToTextile opts contents
  let thisnote = "fn" ++ show newnum ++ ". " ++ contents' ++ "\n"
  modify $ \s -> s { stNotes = thisnote : curNotes }
  return $ "[" ++ show newnum ++ "]"
  -- note - may not work for notes with multiple blocks