{-
Copyright (C) 2007-2015 John MacFarlane <jgm@berkeley.edu>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-}

{- |
   Module      : Text.Pandoc.Writers.Man
   Copyright   : Copyright (C) 2007-2015 John MacFarlane
   License     : GNU GPL, version 2 or above

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

Conversion of 'Pandoc' documents to groff man page format.

-}
module Text.Pandoc.Writers.Man ( writeMan) where
import Control.Monad.Except (throwError)
import Control.Monad.State
import Data.List (intercalate, intersperse, stripPrefix)
import Data.Maybe (fromMaybe)
import Text.Pandoc.Builder (deleteMeta)
import Text.Pandoc.Class (PandocMonad, report)
import Text.Pandoc.Definition
import Text.Pandoc.Error
import Text.Pandoc.Logging
import Text.Pandoc.Options
import Text.Pandoc.Pretty
import Text.Pandoc.Shared
import Text.Pandoc.Templates
import Text.Pandoc.Writers.Math
import Text.Pandoc.Writers.Shared
import Text.Printf (printf)

type Notes = [[Block]]
data WriterState = WriterState { stNotes     :: Notes
                               , stHasTables :: Bool }

-- | Convert Pandoc to Man.
writeMan :: PandocMonad m => WriterOptions -> Pandoc -> m String
writeMan opts document = evalStateT (pandocToMan opts document) (WriterState [] False)

-- | Return groff man representation of document.
pandocToMan :: PandocMonad m => WriterOptions -> Pandoc -> StateT WriterState m String
pandocToMan opts (Pandoc meta blocks) = do
  let colwidth = if writerWrapText opts == WrapAuto
                    then Just $ writerColumns opts
                    else Nothing
  let render' = render colwidth
  titleText <- inlineListToMan opts $ docTitle meta
  let title' = render' titleText
  let setFieldsFromTitle =
       case break (== ' ') title' of
           (cmdName, rest) -> case break (=='(') cmdName of
                                   (xs, '(':ys) | not (null ys) &&
                                                  last ys == ')' ->
                                     defField "title" xs .
                                     defField "section" (init ys) .
                                     case splitBy (=='|') rest of
                                          (ft:hds) ->
                                            defField "footer" (trim ft) .
                                            defField "header"
                                               (trim $ concat hds)
                                          [] -> id
                                   _  -> defField "title" title'
  metadata <- metaToJSON opts
              (fmap (render colwidth) . blockListToMan opts)
              (fmap (render colwidth) . inlineListToMan opts)
              $ deleteMeta "title" meta
  body <- blockListToMan opts blocks
  notes <- gets stNotes
  notes' <- notesToMan opts (reverse notes)
  let main = render' $ body $$ notes' $$ text ""
  hasTables <- gets stHasTables
  let context = defField "body" main
              $ setFieldsFromTitle
              $ defField "has-tables" hasTables
              $ defField "hyphenate" True
              $ defField "pandoc-version" pandocVersion
              $ metadata
  case writerTemplate opts of
       Nothing  -> return main
       Just tpl -> return $ renderTemplate' tpl context

-- | Return man representation of notes.
notesToMan :: PandocMonad m => WriterOptions -> [[Block]] -> StateT WriterState m Doc
notesToMan opts notes =
  if null notes
     then return empty
     else mapM (\(num, note) -> noteToMan opts num note) (zip [1..] notes) >>=
          return . (text ".SH NOTES" $$) . vcat

-- | Return man representation of a note.
noteToMan :: PandocMonad m => WriterOptions -> Int -> [Block] -> StateT WriterState m Doc
noteToMan opts num note = do
  contents <- blockListToMan opts note
  let marker = cr <> text ".SS " <> brackets (text (show num))
  return $ marker $$ contents

-- | Association list of characters to escape.
manEscapes :: [(Char, String)]
manEscapes = [ ('\160', "\\ ")
             , ('\'', "\\[aq]")
             , ('’', "'")
             , ('\x2014', "\\[em]")
             , ('\x2013', "\\[en]")
             , ('\x2026', "\\&...")
             ] ++ backslashEscapes "-@\\"

-- | Escape special characters for Man.
escapeString :: String -> String
escapeString = escapeStringUsing manEscapes

-- | Escape a literal (code) section for Man.
escapeCode :: String -> String
escapeCode = concat . intersperse "\n" . map escapeLine . lines  where
  escapeLine codeline =
    case escapeStringUsing (manEscapes ++ backslashEscapes "\t ") codeline of
      a@('.':_) -> "\\&" ++ a
      b         -> b

-- We split inline lists into sentences, and print one sentence per
-- line.  groff/troff treats the line-ending period differently.
-- See http://code.google.com/p/pandoc/issues/detail?id=148.

-- | Returns the first sentence in a list of inlines, and the rest.
breakSentence :: [Inline] -> ([Inline], [Inline])
breakSentence [] = ([],[])
breakSentence xs =
  let isSentenceEndInline (Str ys@(_:_)) | last ys == '.' = True
      isSentenceEndInline (Str ys@(_:_)) | last ys == '?' = True
      isSentenceEndInline (LineBreak)    = True
      isSentenceEndInline _              = False
      (as, bs) = break isSentenceEndInline xs
  in  case bs of
           []             -> (as, [])
           [c]            -> (as ++ [c], [])
           (c:Space:cs)   -> (as ++ [c], cs)
           (c:SoftBreak:cs) -> (as ++ [c], cs)
           (Str ".":Str (')':ys):cs) -> (as ++ [Str ".", Str (')':ys)], cs)
           (x@(Str ('.':')':_)):cs) -> (as ++ [x], cs)
           (LineBreak:x@(Str ('.':_)):cs) -> (as ++[LineBreak], x:cs)
           (c:cs)         -> (as ++ [c] ++ ds, es)
              where (ds, es) = breakSentence cs

-- | Split a list of inlines into sentences.
splitSentences :: [Inline] -> [[Inline]]
splitSentences xs =
  let (sent, rest) = breakSentence xs
  in  if null rest then [sent] else sent : splitSentences rest

-- | Convert Pandoc block element to man.
blockToMan :: PandocMonad m
           => WriterOptions -- ^ Options
           -> Block         -- ^ Block element
           -> StateT WriterState m Doc
blockToMan _ Null = return empty
blockToMan opts (Div _ bs) = blockListToMan opts bs
blockToMan opts (Plain inlines) =
  liftM vcat $ mapM (inlineListToMan opts) $ splitSentences inlines
blockToMan opts (Para inlines) = do
  contents <- liftM vcat $ mapM (inlineListToMan opts) $
    splitSentences inlines
  return $ text ".PP" $$ contents
blockToMan opts (LineBlock lns) =
  blockToMan opts $ linesToPara lns
blockToMan _ b@(RawBlock f str)
  | f == Format "man" = return $ text str
  | otherwise         = do
      report $ BlockNotRendered b
      return empty
blockToMan _ HorizontalRule = return $ text ".PP" $$ text "   *   *   *   *   *"
blockToMan opts (Header level _ inlines) = do
  contents <- inlineListToMan opts inlines
  let heading = case level of
                  1 -> ".SH "
                  _ -> ".SS "
  return $ text heading <> contents
blockToMan _ (CodeBlock _ str) = return $
  text ".IP" $$
  text ".nf" $$
  text "\\f[C]" $$
  text (escapeCode str) $$
  text "\\f[]" $$
  text ".fi"
blockToMan opts (BlockQuote blocks) = do
  contents <- blockListToMan opts blocks
  return $ text ".RS" $$ contents $$ text ".RE"
blockToMan opts (Table caption alignments widths headers rows) =
  let aligncode AlignLeft    = "l"
      aligncode AlignRight   = "r"
      aligncode AlignCenter  = "c"
      aligncode AlignDefault = "l"
  in do
  caption' <- inlineListToMan opts caption
  modify $ \st -> st{ stHasTables = True }
  let iwidths = if all (== 0) widths
                   then repeat ""
                   else map (printf "w(%0.1fn)" . (70 *)) widths
  -- 78n default width - 8n indent = 70n
  let coldescriptions = text $ intercalate " "
                        (zipWith (\align width -> aligncode align ++ width)
                        alignments iwidths) ++ "."
  colheadings <- mapM (blockListToMan opts) headers
  let makeRow cols = text "T{" $$
                     (vcat $ intersperse (text "T}@T{") cols) $$
                     text "T}"
  let colheadings' = if all null headers
                        then empty
                        else makeRow colheadings $$ char '_'
  body <- mapM (\row -> do
                         cols <- mapM (blockListToMan opts) row
                         return $ makeRow cols) rows
  return $ text ".PP" $$ caption' $$
           text ".TS" $$ text "tab(@);" $$ coldescriptions $$
           colheadings' $$ vcat body $$ text ".TE"

blockToMan opts (BulletList items) = do
  contents <- mapM (bulletListItemToMan opts) items
  return (vcat contents)
blockToMan opts (OrderedList attribs items) = do
  let markers = take (length items) $ orderedListMarkers attribs
  let indent = 1 + (maximum $ map length markers)
  contents <- mapM (\(num, item) -> orderedListItemToMan opts num indent item) $
              zip markers items
  return (vcat contents)
blockToMan opts (DefinitionList items) = do
  contents <- mapM (definitionListItemToMan opts) items
  return (vcat contents)

-- | Convert bullet list item (list of blocks) to man.
bulletListItemToMan :: PandocMonad m => WriterOptions -> [Block] -> StateT WriterState m Doc
bulletListItemToMan _ [] = return empty
bulletListItemToMan opts ((Para first):rest) =
  bulletListItemToMan opts ((Plain first):rest)
bulletListItemToMan opts ((Plain first):rest) = do
  first' <- blockToMan opts (Plain first)
  rest' <- blockListToMan opts rest
  let first'' = text ".IP \\[bu] 2" $$ first'
  let rest''  = if null rest
                   then empty
                   else text ".RS 2" $$ rest' $$ text ".RE"
  return (first'' $$ rest'')
bulletListItemToMan opts (first:rest) = do
  first' <- blockToMan opts first
  rest' <- blockListToMan opts rest
  return $ text "\\[bu] .RS 2" $$ first' $$ rest' $$ text ".RE"

-- | Convert ordered list item (a list of blocks) to man.
orderedListItemToMan :: PandocMonad m
                     => WriterOptions -- ^ options
                     -> String   -- ^ order marker for list item
                     -> Int      -- ^ number of spaces to indent
                     -> [Block]  -- ^ list item (list of blocks)
                     -> StateT WriterState m Doc
orderedListItemToMan _ _ _ [] = return empty
orderedListItemToMan opts num indent ((Para first):rest) =
  orderedListItemToMan opts num indent ((Plain first):rest)
orderedListItemToMan opts num indent (first:rest) = do
  first' <- blockToMan opts first
  rest' <- blockListToMan opts rest
  let num' = printf ("%" ++ show (indent - 1) ++ "s") num
  let first'' = text (".IP \"" ++ num' ++ "\" " ++ show indent) $$ first'
  let rest''  = if null rest
                   then empty
                   else text ".RS 4" $$ rest' $$ text ".RE"
  return $ first'' $$ rest''

-- | Convert definition list item (label, list of blocks) to man.
definitionListItemToMan :: PandocMonad m
                        => WriterOptions
                        -> ([Inline],[[Block]])
                        -> StateT WriterState m Doc
definitionListItemToMan opts (label, defs) = do
  labelText <- inlineListToMan opts label
  contents <- if null defs
                 then return empty
                 else liftM vcat $ forM defs $ \blocks -> do
                        (first, rest) <- case blocks of
                          ((Para x):y) -> return (Plain x,y)
                          (x:y)        -> return (x,y)
                          []           -> throwError $ PandocSomeError "blocks is null"
                        rest' <- liftM vcat $
                                  mapM (\item -> blockToMan opts item) rest
                        first' <- blockToMan opts first
                        return $ first' $$ text ".RS" $$ rest' $$ text ".RE"
  return $ text ".TP" $$ nowrap (text ".B " <> labelText) $$ contents

-- | Convert list of Pandoc block elements to man.
blockListToMan :: PandocMonad m
               => WriterOptions -- ^ Options
               -> [Block]       -- ^ List of block elements
               -> StateT WriterState m Doc
blockListToMan opts blocks =
  mapM (blockToMan opts) blocks >>= (return . vcat)

-- | Convert list of Pandoc inline elements to man.
inlineListToMan :: PandocMonad m => WriterOptions -> [Inline] -> StateT WriterState m Doc
inlineListToMan opts lst = mapM (inlineToMan opts) lst >>= (return . hcat)

-- | Convert Pandoc inline element to man.
inlineToMan :: PandocMonad m => WriterOptions -> Inline -> StateT WriterState m Doc
inlineToMan opts (Span _ ils) = inlineListToMan opts ils
inlineToMan opts (Emph lst) = do
  contents <- inlineListToMan opts lst
  return $ text "\\f[I]" <> contents <> text "\\f[]"
inlineToMan opts (Strong lst) = do
  contents <- inlineListToMan opts lst
  return $ text "\\f[B]" <> contents <> text "\\f[]"
inlineToMan opts (Strikeout lst) = do
  contents <- inlineListToMan opts lst
  return $ text "[STRIKEOUT:" <> contents <> char ']'
inlineToMan opts (Superscript lst) = do
  contents <- inlineListToMan opts lst
  return $ char '^' <> contents <> char '^'
inlineToMan opts (Subscript lst) = do
  contents <- inlineListToMan opts lst
  return $ char '~' <> contents <> char '~'
inlineToMan opts (SmallCaps lst) = inlineListToMan opts lst -- not supported
inlineToMan opts (Quoted SingleQuote lst) = do
  contents <- inlineListToMan opts lst
  return $ char '`' <> contents <> char '\''
inlineToMan opts (Quoted DoubleQuote lst) = do
  contents <- inlineListToMan opts lst
  return $ text "\\[lq]" <> contents <> text "\\[rq]"
inlineToMan opts (Cite _ lst) =
  inlineListToMan opts lst
inlineToMan _ (Code _ str) =
  return $ text $ "\\f[C]" ++ escapeCode str ++ "\\f[]"
inlineToMan _ (Str str@('.':_)) =
  return $ afterBreak "\\&" <> text (escapeString str)
inlineToMan _ (Str str) = return $ text $ escapeString str
inlineToMan opts (Math InlineMath str) =
  lift (texMathToInlines InlineMath str) >>= inlineListToMan opts
inlineToMan opts (Math DisplayMath str) = do
  contents <- lift (texMathToInlines DisplayMath str) >>= inlineListToMan opts
  return $ cr <> text ".RS" $$ contents $$ text ".RE"
inlineToMan _ il@(RawInline f str)
  | f == Format "man" = return $ text str
  | otherwise         = do
      report $ InlineNotRendered il
      return empty
inlineToMan _ LineBreak = return $
  cr <> text ".PD 0" $$ text ".P" $$ text ".PD" <> cr
inlineToMan _ SoftBreak = return space
inlineToMan _ Space = return space
inlineToMan opts (Link _ txt (src, _)) = do
  linktext <- inlineListToMan opts txt
  let srcSuffix = fromMaybe src (stripPrefix "mailto:" src)
  return $ case txt of
           [Str s]
             | escapeURI s == srcSuffix ->
                                 char '<' <> text srcSuffix <> char '>'
           _                  -> linktext <> text " (" <> text src <> char ')'
inlineToMan opts (Image attr alternate (source, tit)) = do
  let txt = if (null alternate) || (alternate == [Str ""]) ||
               (alternate == [Str source]) -- to prevent autolinks
               then [Str "image"]
               else alternate
  linkPart <- inlineToMan opts (Link attr txt (source, tit))
  return $ char '[' <> text "IMAGE: " <> linkPart <> char ']'
inlineToMan _ (Note contents) = do
  -- add to notes in state
  modify $ \st -> st{ stNotes = contents : stNotes st }
  notes <- gets stNotes
  let ref = show $ (length notes)
  return $ char '[' <> text ref <> char ']'