-- Create pandoc.1 man and pandoc_markdown.5 man pages from README
import Text.Pandoc
import Data.ByteString.UTF8 (toString, fromString)
import Data.Char (toUpper)
import qualified Data.ByteString as B
import Control.Monad
import System.FilePath
import System.Environment (getArgs)
import Text.Pandoc.Shared (normalize)

main = do
  rmContents <- liftM toString $ B.readFile "README"
  let (Pandoc meta blocks) = readMarkdown def rmContents
  let manBlocks = removeSect [Str "Wrappers"]
                $ removeSect [Str "Pandoc's",Space,Str "markdown"] blocks
  let syntaxBlocks = extractSect [Str "Pandoc's",Space,Str "markdown"] blocks
  args <- getArgs
  let verbose = "--verbose" `elem` args
  makeManPage verbose ("man" </> "man1" </> "pandoc.1")
      meta manBlocks
  makeManPage verbose ("man" </> "man5" </> "pandoc_markdown.5")
      meta syntaxBlocks

makeManPage :: Bool -> FilePath -> Meta -> [Block] -> IO ()
makeManPage verbose page meta blocks = do
  let templ = page <.> "template"
  manTemplate <- liftM toString $ B.readFile templ
  writeManPage page manTemplate (Pandoc meta blocks)
  when verbose $ putStrLn $ "Created " ++ page

writeManPage :: FilePath -> String -> Pandoc -> IO ()
writeManPage page templ doc = do
  let opts = def{ writerStandalone = True
                , writerTemplate = templ }
  let manPage = writeMan opts $
                    bottomUp (concatMap removeLinks) $
                    bottomUp  capitalizeHeaders doc
  B.writeFile page $ fromString manPage

removeLinks :: Inline -> [Inline]
removeLinks (Link l _) = l
removeLinks x = [x]

capitalizeHeaders :: Block -> Block
capitalizeHeaders (Header 1 xs) = Header 1 $ bottomUp capitalize xs
capitalizeHeaders x = x

capitalize :: Inline -> Inline
capitalize (Str xs) = Str $ map toUpper xs
capitalize x = x

removeSect :: [Inline] -> [Block] -> [Block]
removeSect ils (Header 1 x:xs) | normalize x == normalize ils =
  dropWhile (not . isHeader1) xs
removeSect ils (x:xs) = x : removeSect ils xs
removeSect _ [] = []

extractSect :: [Inline] -> [Block] -> [Block]
extractSect ils (Header 1 z:xs) | normalize z == normalize ils =
  bottomUp promoteHeader $ takeWhile (not . isHeader1) xs
    where promoteHeader (Header n x) = Header (n-1) x
          promoteHeader x            = x
extractSect ils (x:xs) = extractSect ils xs
extractSect _ [] = []

isHeader1 :: Block -> Bool
isHeader1 (Header 1 _) = True
isHeader1 _            = False