{-# LANGUAGE LambdaCase        #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ViewPatterns      #-}
{- |
   Module      : Text.Pandoc.Writers.Man
   Copyright   : Copyright (C) 2007-2022 John MacFarlane
   License     : GNU GPL, version 2 or above

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

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

-}
module Text.Pandoc.Writers.Man ( writeMan ) where
import Control.Monad.State.Strict
import Data.List (intersperse)
import Data.List.NonEmpty (nonEmpty)
import Data.Maybe (fromMaybe)
import Data.Text (Text)
import qualified Data.Text as T
import Text.Pandoc.Builder (deleteMeta)
import Text.Pandoc.Class.PandocMonad (PandocMonad, report)
import Text.Pandoc.Definition
import Text.Pandoc.Logging
import Text.Pandoc.Options
import Text.DocLayout
import Text.Pandoc.Shared
import Text.Pandoc.Templates (renderTemplate)
import Text.Pandoc.Writers.Math
import Text.Pandoc.Writers.Shared
import Text.Pandoc.Writers.Roff
import Text.Printf (printf)

-- | Convert Pandoc to Man.
writeMan :: PandocMonad m => WriterOptions -> Pandoc -> m Text
writeMan opts document =
  evalStateT (pandocToMan opts document) defaultWriterState

-- | Return roff man representation of document.
pandocToMan :: PandocMonad m => WriterOptions -> Pandoc -> StateT WriterState m Text
pandocToMan opts (Pandoc meta blocks) = do
  let colwidth = if writerWrapText opts == WrapAuto
                    then Just $ writerColumns opts
                    else Nothing
  titleText <- inlineListToMan opts $ docTitle meta
  let title' = render Nothing titleText
  let setFieldsFromTitle =
       case T.break (== ' ') title' of
           (cmdName, rest) -> case T.break (=='(') cmdName of
                                   (xs, ys) | "(" `T.isPrefixOf` ys
                                                && ")" `T.isSuffixOf` ys ->
                                     defField "title" xs .
                                     defField "section" (T.init $ T.drop 1 ys) .
                                     case T.splitOn "|" rest of
                                          (ft:hds) ->
                                            defField "footer" (T.strip ft) .
                                            defField "header"
                                               (T.strip $ mconcat hds)
                                          [] -> id
                                   _  -> defField "title" title'
  metadata <- metaToContext opts
              (blockListToMan opts)
              (fmap chomp . inlineListToMan opts)
              $ deleteMeta "title" meta
  body <- blockListToMan opts blocks
  notes <- gets stNotes
  notes' <- notesToMan opts (reverse notes)
  let main = body $$ notes' $$ text ""
  hasTables <- gets stHasTables
  let context = defField "body" main
              $ setFieldsFromTitle
              $ defField "has-tables" hasTables
              $ defField "hyphenate" True
              $ defField "pandoc-version" pandocVersion metadata
  return $ render colwidth $
    case writerTemplate opts of
       Nothing  -> main
       Just tpl -> renderTemplate tpl context

escString :: WriterOptions -> Text -> Text
escString _ = escapeString AsciiOnly -- for better portability

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

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

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

-- | Convert Pandoc block element to man.
blockToMan :: PandocMonad m
           => WriterOptions -- ^ Options
           -> Block         -- ^ Block element
           -> StateT WriterState m (Doc Text)
blockToMan _ Null = return empty
blockToMan opts (Div _ bs) = blockListToMan opts bs
blockToMan opts (Plain inlines) =
  splitSentences <$> inlineListToMan opts inlines
blockToMan opts (Para inlines) = do
  contents <- inlineListToMan opts inlines
  return $ text ".PP" $$ splitSentences contents
blockToMan opts (LineBlock lns) =
  blockToMan opts $ linesToPara lns
blockToMan _ b@(RawBlock f str)
  | f == Format "man" = return $ literal str
  | otherwise         = do
      report $ BlockNotRendered b
      return empty
blockToMan _ HorizontalRule = return $ literal ".PP" $$ literal "   *   *   *   *   *"
blockToMan opts (Header level _ inlines) = do
  contents <- inlineListToMan opts inlines
  let heading = case level of
                  1 -> ".SH "
                  _ -> ".SS "
  return $ nowrap $ literal heading <> contents
blockToMan opts (CodeBlock _ str) = return $
  literal ".IP" $$
  literal ".nf" $$
  literal "\\f[C]" $$
  ((case T.uncons str of
    Just ('.',_) -> literal "\\&"
    _            -> mempty) <>
   literal (escString opts str)) $$
  literal "\\f[R]" $$
  literal ".fi"
blockToMan opts (BlockQuote blocks) = do
  contents <- blockListToMan opts blocks
  return $ literal ".RS" $$ contents $$ literal ".RE"
blockToMan opts (Table _ blkCapt specs thead tbody tfoot) =
  let (caption, alignments, widths, headers, rows) = toLegacyTable blkCapt specs thead tbody tfoot
      aligncode AlignLeft    = "l"
      aligncode AlignRight   = "r"
      aligncode AlignCenter  = "c"
      aligncode AlignDefault = "l"
  in do
  caption' <- inlineListToMan opts caption
  modify $ \st -> st{ stHasTables = True }
  let iwidths = if all (== 0) widths
                   then repeat ""
                   else map (T.pack . printf "w(%0.1fn)" . (70 *)) widths
  -- 78n default width - 8n indent = 70n
  let coldescriptions = literal $ T.unwords
                        (zipWith (\align width -> aligncode align <> width)
                        alignments iwidths) <> "."
  colheadings <- mapM (blockListToMan opts) headers
  let makeRow cols = literal "T{" $$
                     vcat (intersperse (literal "T}@T{") cols) $$
                     literal "T}"
  let colheadings' = if all null headers
                        then empty
                        else makeRow colheadings $$ char '_'
  body <- mapM (\row -> do
                         cols <- mapM (blockListToMan opts) row
                         return $ makeRow cols) rows
  return $ literal ".PP" $$ caption' $$
           literal ".TS" $$ literal "tab(@);" $$ coldescriptions $$
           colheadings' $$ vcat body $$ literal ".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 + maybe 0 maximum (nonEmpty (map T.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 Text)
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'' = literal ".IP \\[bu] 2" $$ first'
  let rest''  = if null rest
                   then empty
                   else literal ".RS 2" $$ rest' $$ literal ".RE"
  return (first'' $$ rest'')
bulletListItemToMan opts (first:rest) = do
  first' <- blockToMan opts first
  rest' <- blockListToMan opts rest
  return $ literal "\\[bu] .RS 2" $$ first' $$ rest' $$ literal ".RE"

-- | Convert ordered list item (a list of blocks) to man.
orderedListItemToMan :: PandocMonad m
                     => WriterOptions -- ^ options
                     -> Text   -- ^ order marker for list item
                     -> Int      -- ^ number of spaces to indent
                     -> [Block]  -- ^ list item (list of blocks)
                     -> StateT WriterState m (Doc Text)
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'' = literal (".IP \"" <> T.pack num' <> "\" " <> tshow indent) $$ first'
  let rest''  = if null rest
                   then empty
                   else literal ".RS 4" $$ rest' $$ literal ".RE"
  return $ first'' $$ rest''

-- | Convert definition list item (label, list of blocks) to man.
definitionListItemToMan :: PandocMonad m
                        => WriterOptions
                        -> ([Inline],[[Block]])
                        -> StateT WriterState m (Doc Text)
definitionListItemToMan opts (label, defs) = do
  -- in most man pages, option and other code in option lists is boldface,
  -- but not other things, so we try to reproduce this style:
  labelText <- inlineListToMan opts label
  contents <- if null defs
                 then return empty
                 else liftM vcat $ forM defs $ \case
                          (x:xs) -> do
                            first' <- blockToMan opts $
                                      case x of
                                           Para y -> Plain y
                                           _      -> x
                            rest' <- liftM vcat $ mapM
                                        (\item -> blockToMan opts item) xs
                            return $ first' $$
                                     if null xs
                                        then empty
                                        else literal ".RS" $$ rest' $$ literal ".RE"
                          [] -> return empty
  return $ literal ".TP" $$ nowrap labelText $$ contents

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

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

-- | Convert Pandoc inline element to man.
inlineToMan :: PandocMonad m => WriterOptions -> Inline -> StateT WriterState m (Doc Text)
inlineToMan opts (Span _ ils) = inlineListToMan opts ils
inlineToMan opts (Emph lst) =
  withFontFeature 'I' (inlineListToMan opts lst)
-- Underline is not supported, so treat the same as Emph
inlineToMan opts (Underline lst) =
  withFontFeature 'I' (inlineListToMan opts lst)
inlineToMan opts (Strong lst) =
  withFontFeature 'B' (inlineListToMan opts lst)
inlineToMan opts (Strikeout lst) = do
  contents <- inlineListToMan opts lst
  return $ literal "[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 $ literal "\\[lq]" <> contents <> literal "\\[rq]"
inlineToMan opts (Cite _ lst) =
  inlineListToMan opts lst
inlineToMan opts (Code _ str) =
  -- note that the V font is specially defined in the default man template
  withFontFeature 'V' (return (literal $ escString opts str))
inlineToMan opts (Str str@(T.uncons -> Just ('.',_))) =
  return $ afterBreak "\\&" <> literal (escString opts str)
inlineToMan opts (Str str) = return $ literal $ escString opts 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 <> literal ".RS" $$ contents $$ literal ".RE"
inlineToMan _ il@(RawInline f str)
  | f == Format "man" = return $ literal str
  | otherwise         = do
      report $ InlineNotRendered il
      return empty
inlineToMan _ LineBreak = return $
  cr <> literal ".PD 0" $$ literal ".P" $$ literal ".PD" <> cr
inlineToMan _ SoftBreak = return space
inlineToMan _ Space = return space
inlineToMan opts (Link _ txt (src, _))
  | not (isURI src) = inlineListToMan opts txt -- skip relative links
  | otherwise       = do
  linktext <- inlineListToMan opts txt
  let srcSuffix = fromMaybe src (T.stripPrefix "mailto:" src)
  return $ case txt of
           [Str s]
             | escapeURI s == srcSuffix ->
                                 char '<' <> literal srcSuffix <> char '>'
           _                  -> linktext <> literal " (" <> literal 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 '[' <> literal "IMAGE: " <> linkPart <> char ']'
inlineToMan _ (Note contents) = do
  -- add to notes in state
  modify $ \st -> st{ stNotes = contents : stNotes st }
  notes <- gets stNotes
  let ref = tshow (length notes)
  return $ char '[' <> literal ref <> char ']'
