module Options.Utils
       ( rCI
       , rTime
       , pRange
       ) where

import Options.Applicative

import Data.Char
import Data.Maybe
import Data.List
import Text.Read

import Data.Time

import Thermoprint.Client (Range(..))

rCI :: (Read a, Show a) => ReadM a
rCI = eitherReader rRep'
  where
    rRep' str = case mapMaybe readMaybe $ cases str of
      []  -> Left $ "Could not parse `" ++ str ++ "'"
      [x] -> Right x
      xs  -> Left $ "Ambiguous parse for `" ++ str ++ "': " ++ show xs
    cases []     = []
    cases (c:cs) = [(c':cs') | c' <- [toLower c, toUpper c], cs' <- cases cs]

rTime :: ReadM UTCTime
rTime = eitherReader rTime'
  where
    rTime' str = maybe (Left $ "Could not parse `" ++ str ++ "' as a specification of time -- try the output of `date -u +'%Y-%m-%d %H:%M:%S' \"" ++ str ++ "\"`") Right
      . foldr (<|>) Nothing
      $ map (flip (parseTimeM True defaultTimeLocale) str) ( "%c" : "%s" : perms' [ [time, date, timezone] | time <- ["%T", "%X", "%I:%M:%S", "%r", "%X%Q", "%I:%M:%S%Q %p"], date <- ["%x", "%F"], timezone <- ["%z", "%Z"]] )
    perms' :: [[String]] -> [String]
    perms' = map unwords . concatMap subsequences . concatMap permutations

pRange :: ReadM a
          -> Mod OptionFields a -- ^ Modifiers applied to both min & max
          -> Mod OptionFields a -- ^ Modifiers for minimum
          -> Mod OptionFields a -- ^ Modifiers for maximum
          -> Parser (Maybe (Range a))
pRange r both min max = toRange <$> optional (option r (both <> min)) <*> optional (option r (both <> max))
  where
    toRange Nothing Nothing = Nothing
    toRange (Just min) Nothing = Just $ Min min
    toRange Nothing (Just max) = Just $ Max max
    toRange (Just min) (Just max) = Just $ min `Through` max