{-# LANGUAGE DeriveGeneric #-}
module Distribution.Client.Types.OverwritePolicy where

import Distribution.Client.Compat.Prelude
import Prelude ()

import qualified Distribution.Compat.CharParsing as P
import qualified Text.PrettyPrint                as PP

data OverwritePolicy
    = NeverOverwrite
    | AlwaysOverwrite
  deriving (Show, Eq, Generic, Bounded, Enum)

instance Binary OverwritePolicy
instance Structured OverwritePolicy

instance Parsec OverwritePolicy where
    parsec = do
        name <- P.munch1 isAlpha
        case name of
            "always" -> pure AlwaysOverwrite
            "never"  -> pure NeverOverwrite
            _        -> P.unexpected $ "OverwritePolicy: " ++ name

instance Pretty OverwritePolicy where
    pretty NeverOverwrite  = PP.text "never"
    pretty AlwaysOverwrite = PP.text "always"