{-# LANGUAGE NamedFieldPuns #-}
{- LANGUAGE OverloadedStrings #-}
module Article (
      Article(..)
    , at
  ) where

import Control.Monad.State (evalState, state)
import Data.Text (Text, pack)
import System.FilePath ((</>))
import System.Posix.Types (FileID)
import System.Posix.Files (FileStatus, getFileStatus, fileID)

data Article = Article {
      urlPath :: Text
    , fileStatus :: FileStatus
    , title :: String
    , preview :: String
  }

parseBegining :: Int -> String -> (String, String)
parseBegining linesCount = evalState (do
    first <- state $ splitAt 1
    second <- state $ splitAt linesCount
    return (unlines first, unlines second)
  ) . lines

at :: Int -> FilePath -> IO (FileID, Article)
at linesCount filePath = do
  fileStatus <- getFileStatus filePath
  (title, preview) <- parseBegining linesCount <$> readFile filePath
  return (
        fileID fileStatus
      , Article {
              urlPath = pack $ "/" </> filePath
            , fileStatus
            , title
            , preview
          }
    )