{-# LANGUAGE CPP #-}

module Main where
import Data.Spreadsheet as S
import Control.Monad.Exception.Asynchronous.Lazy as AsExc
import Control.Monad (liftM)
import Data.Monoid (mempty)
import Data.Char (toUpper)
import Data.List (isSuffixOf)
import Text.Pandoc.JSON
import Text.Pandoc.Definition
import Text.Pandoc.Builder (Inlines, Blocks, toList, fromList, table, para, str)

#if defined(INLINE_MARKDOWN)
import Text.Pandoc.Readers.Markdown
import Text.Pandoc.Options
#endif


main :: IO ()
main = toJSONFilter placeTable

placeTable :: Block -> IO [Block]
placeTable (CodeBlock (_, cls, kvs) txt) | "table" `elem` cls = do
  csv <- case lookup "file" kvs of
           Just name -> readFile name
           Nothing   -> return ""
  let header = case lookup "header" kvs of
                 Just "yes" -> True
                 _ -> False
  let toAlign c = case toUpper c of
                    'L' -> AlignLeft
                    'R' -> AlignRight
                    'C' -> AlignCenter
                    _   -> AlignDefault
  let aligns = case lookup "aligns" kvs of
                 Just as -> map toAlign as
                 Nothing -> repeat AlignDefault
  let capt = case lookup "caption" kvs of
               Just c  -> strToInlines c
               Nothing -> mempty
  let qc   = case lookup "quotechar" kvs of
               Just q  -> head q
               Nothing -> '"'
  let sep  = case lookup "delimiter" kvs of
               Just d  -> if head d == '\\'
                             then case head (tail d) of
                                    't' -> '\t'
                                    's' -> ' '
                                    _   -> '\\'
                             else head d
               Nothing -> ','
  let s' = if null txt
             then csv
             else txt ++ "\n" ++ csv
  let s = if isSuffixOf "\n" s'
             then s'
             else s' ++ "\n"
  return $ toList $ csvToTable header aligns capt qc sep s
placeTable a = return [a]


-- | Convert a CSV String to a Pandoc Table
simpleCsvToTable :: String -> Blocks
simpleCsvToTable s = csvToTable False (repeat AlignDefault) mempty '"' ',' s

-- | Convert a bunch of options and a CSV String to a Pandoc Table
csvToTable :: Bool        -- ^ interpret first row as headers
           -> [Alignment] -- ^ table column alignments
           -> Inlines     -- ^ table caption
           -> Char        -- ^ csv quotation character like "
           -> Char        -- ^ csv field separator like ,
           -> String      -- ^ csv string to parse
           -> Blocks
csvToTable header aligns caption qc sep s =
  table caption cellspecs (map strToBlocks headers) $ (map . map) strToBlocks rows
  where
    exc = S.fromString qc sep s
    rows' = case  exception exc of
              Nothing -> result exc
              Just e  -> [["Error parsing CSV: " ++ e]]
    (headers, rows) = if header && length rows' > 0
                         then (head rows', tail rows')
                         else ([], rows')
    cols = if null rows' then 0 else length $ head rows'
    cellspecs = zip aligns $ replicate cols 0


strToInlines :: String -> Inlines
strToInlines s =
#if defined(INLINE_MARKDOWN)
 case readMarkdown def s of
                   Right (Pandoc _ bs) -> fromList $ extractIns $ head bs
                   Left e -> str $ show e
  where
    extractIns (Para ins) = ins
    extractIns _ = []
#else
  str s
#endif

strToBlocks :: String -> Blocks
strToBlocks s =
#if defined(INLINE_MARKDOWN)
  case readMarkdown def s of
    Right (Pandoc _ bs) -> fromList bs
    Left e -> para $ str $ show e
#else
  para $ str s
#endif