{-# LANGUAGE CPP             #-}
{-# LANGUAGE RecordWildCards #-}

module Configuration.Dotenv.Scheme.Helpers
  ( joinEnvs
  , matchValueAndType
  , missingDotenvs
  , missingSchemeEnvs
  , sepWithCommas
  , showMissingDotenvs
  , showMissingSchemeEnvs
  )
  where

#if !MIN_VERSION_base(4,8,0)
import Data.Functor ((<$>))
import Control.Applicative ((<*>))
#endif
import Data.List

import Configuration.Dotenv.Scheme.Types

matchValueAndType
  :: [(Env, (String, String))]
  -> [(String, EnvType)]
matchValueAndType =
  let getValueAndType (Env{..}, (_, value)) = (value, envType)
   in map getValueAndType

joinEnvs
  :: [Env]
  -> [(String, String)]
  -> [(Env, (String, String))]
joinEnvs =
  let sameName (Env{..}, (name,_)) = envName == name
   in joinBy sameName

joinBy :: ((a,b) -> Bool) -> [a] -> [b] -> [(a,b)]
joinBy p xs ys =
  let cartesianProduct = (,) <$> xs <*> ys
   in filter p cartesianProduct

missingDotenvs
  :: [Env]
  -> [(Env, (String, String))]
  -> [Env]
missingDotenvs =
  let sameName envOne envTwo = envName envOne == envName envTwo
   in missingLeft sameName

missingLeft :: (a -> a -> Bool) -> [a] -> [(a,b)] -> [a]
missingLeft p xs xys =
  let getAllLeft = map fst xys
   in deleteFirstsBy p xs getAllLeft

missingSchemeEnvs
  :: [(String, String)]
  -> [(Env, (String, String))]
  -> [(String, String)]
missingSchemeEnvs =
  let sameName (nameOne,_) (nameTwo,_) = nameOne == nameTwo
   in missingRight sameName

missingRight :: (b -> b -> Bool) -> [b] -> [(a,b)] -> [b]
missingRight p ys xys =
  let getAllRight = map snd xys
   in deleteFirstsBy p ys getAllRight

sepWithCommas :: [String] -> String
sepWithCommas = intercalate ", "

showMissingDotenvs :: [Env] -> String
showMissingDotenvs = sepWithCommas . map envName

showMissingSchemeEnvs :: [(String, String)] -> String
showMissingSchemeEnvs = sepWithCommas . map fst