{-# LANGUAGE NoImplicitPrelude #-}

-- | Names for packages.

module Stack.Types.PackageName
  ( packageNameArgument
  ) where

import qualified Options.Applicative as O
import           Stack.Prelude

-- | An argument which accepts a template name of the format
-- @foo.hsfiles@.
packageNameArgument :: O.Mod O.ArgumentFields PackageName
                    -> O.Parser PackageName
packageNameArgument =
  O.argument
    (do s <- O.str
        either O.readerError pure (p s))
 where
  p s =
    case parsePackageName s of
      Just x -> Right x
      Nothing -> Left $ unlines
        [ "Expected valid package name, but got: " ++ s
        , "Package names consist of one or more alphanumeric words separated \
          \by hyphens."
        , "To avoid ambiguity with version numbers, each of these words must \
          \contain at least one letter."
        ]