-- | Module with function to read file in with pandoc and discard everything superfluous.
module Data.Text.WordCount.FileRead ( processFile
                                    , globFile
                                    ) where

import           Control.Monad             ((<=<))
import           Control.Monad.IO.Class    (liftIO)
import qualified Data.ByteString.Lazy      as BSL
import qualified Data.Text                 as T
import qualified Data.Text.IO              as TIO
import           Filesystem.Path.CurrentOS as F
import           System.FilePath.Glob
import           Text.Pandoc               hiding (glob)

-- | Process files given a filename glob
globFile :: String -> IO T.Text
globFile str = do
    files <- glob str
    fmap T.concat . sequence $ fmap runIOorExplode $ fmap processFile files

-- | Process a file given a filename. Return text only, discarding superflouous material.
processFile :: String -> PandocIO T.Text
processFile filepath = (T.filter goodChar) <$> case (extension . decodeString $ filepath) of
    (Just "md") -> (writePlain def <=< fmap filterCode . (readMarkdown def =<<)) <$> liftIO $ TIO.readFile filepath
    (Just "dbk") -> (writePlain def <=< fmap filterCode . (readDocBook def =<<)) <$> liftIO $ TIO.readFile filepath
    (Just "docx") -> (writePlain def <=< fmap filterCode . (readDocx def =<<)) $ liftIO $ BSL.readFile filepath
    (Just "epub") -> (writePlain def <=< fmap filterCode . (readEPUB def =<<)) $ liftIO $ BSL.readFile filepath
    (Just "html") -> (writePlain def <=< fmap filterCode . (readHtml def =<<)) $ liftIO $ TIO.readFile filepath
    (Just "tex") -> (writePlain def <=< fmap filterCode . (readLaTeX def =<<)) $ liftIO $ TIO.readFile filepath
    (Just "xml") -> (writePlain def <=< fmap filterCode . (readOPML def =<<)) $ liftIO $ TIO.readFile filepath
    (Just "odt") -> (writePlain def <=< fmap filterCode . (readOdt def =<<)) $ liftIO $ BSL.readFile filepath
    (Just "rst") -> (writePlain def <=< fmap filterCode . (readRST def =<<)) $ liftIO $ TIO.readFile filepath
    (Just "textile") -> (writePlain def <=< fmap filterCode . (readTextile def =<<)) $ liftIO $ TIO.readFile filepath
    _ -> liftIO $ TIO.readFile filepath

goodChar :: Char -> Bool
goodChar = not . flip any (".,?_()![]{}*&$#" :: String) . (==)

-- | Filter out code and tables from the document
filterCode :: Pandoc -> Pandoc
filterCode (Pandoc meta content) = Pandoc meta $ filter rightBlock content
    where rightBlock CodeBlock { } = False
          rightBlock Table { }     = False
          rightBlock _             = True