module CLI (
      Invocation(..)
    , Mode(..)
    , invoked
  ) where

import Options.Applicative (
      Parser, auto, execParser, flag, fullDesc, header, help, helper, info
    , infoOption, long, option, short, value
  )
import Control.Applicative ((<**>), optional)
import Data.Monoid ((<>))
import Data.Time (Day)
import Data.Version (showVersion)
import qualified Paths_pilu as Pilu (version)

data Mode = Inventory | Schedule

data Invocation = Invocation {
      mode :: Mode
    , date :: Maybe Day
  }

versionStr :: String
versionStr = showVersion Pilu.version

version :: Parser (Invocation -> Invocation)
version =
  infoOption versionStr
  (short 'v' <> long "version" <> help "Show the version number")

invocation :: Parser Invocation
invocation = Invocation
  <$> flag Schedule Inventory
      (short 'i' <> long "inventory" <> help "Show a full inventory")
  <*> option (optional auto) (
          value Nothing
        <> short 'd'
        <> long "date"
        <> help "Evaluate the situation at that date"
      )

invoked :: IO Invocation
invoked = execParser $
  info
    (invocation <**> version <**> helper)
    (fullDesc <> header ("Pilu v" ++ versionStr))