hablo/src/Arguments.hs

{-# LANGUAGE NamedFieldPuns #-}
module Arguments (
      Arguments(..)
    , configuration
  ) where

import Options.Applicative
import System.FilePath.Posix (dropTrailingPathSeparator, isValid)

data Arguments = Arguments {
      sourceDir :: FilePath
    , blogName :: Maybe String
    , previewCountArg :: Int
  }

arguments :: Parser Arguments
arguments = Arguments
  <$> argument directory (metavar "INPUT_DIR")
  <*> option (optional str) (
          metavar "BLOG_NAME"
        <> value Nothing
        <> short 'n'
        <> long "name"
        <> help "name of the blog"
      )
  <*> option auto (
          metavar "PREVIEW_COUNT"
        <> value 3
        <> short 'p'
        <> long "preview-count"
        <> help "number of articles listed on the page of each category"
      )

directory :: ReadM FilePath
directory = eitherReader $ \path ->
  if isValid path
    then Right $ dropTrailingPathSeparator path
    else Left "This string doesn't represent a valid path"

configuration :: IO Arguments
configuration =
  execParser $
    info (arguments <**> helper)
      ( fullDesc
      )