Embed.hs

{-# LANGUAGE FlexibleContexts #-}

-- | These helper functions are usually used with 'Data.FileEmbed.embedFile'.
module Octane.Utility.Embed (decodeBimap, decodeMap, decodeSet) where

import Data.Function ((&))

import qualified Data.Aeson as Aeson
import qualified Data.Bimap as Bimap
import qualified Data.ByteString as StrictBytes
import qualified Data.Map.Strict as Map
import qualified Data.Maybe as Maybe
import qualified Data.Set as Set


-- | Decodes some bytes into a bidirection map. The bytes are assumed to be a
-- JSON object mapping values to keys. That means the resulting bimap is
-- 'Bimap.twist'ed from what you might expect.
--
-- >>> decodeBimap "{ \"value\": \"key\" }" :: Bimap.Bimap String String
-- fromList [("key","value")]
decodeBimap
    :: (Aeson.FromJSON (Map.Map b a), Ord a, Ord b)
    => StrictBytes.ByteString
    -> Bimap.Bimap a b
decodeBimap bytes = bytes
    & Aeson.decodeStrict
    & Maybe.fromMaybe Map.empty
    & Map.toList
    & Bimap.fromList
    & Bimap.twist


-- | Decodes some bytes into a map. The bytes are assumed to be a JSON object
-- mapping keys to values.
--
-- >>> decodeMap "{ \"key\": \"value\" }" :: Map.Map String String
-- fromList [("key","value")]
decodeMap
    :: (Aeson.FromJSON (Map.Map a b))
    => StrictBytes.ByteString
    -> Map.Map a b
decodeMap bytes = bytes
    & Aeson.decodeStrict
    & Maybe.fromMaybe Map.empty


-- | Decodes some bytes into a set. The bytes are assumed to be a JSON array.
--
-- >>> decodeSet "[\"element\"]" :: Set.Set String
-- fromList ["element"]
decodeSet
    :: (Aeson.FromJSON a, Ord a)
    => StrictBytes.ByteString
    -> Set.Set a
decodeSet bytes = bytes
    & Aeson.decodeStrict
    & Maybe.fromMaybe Set.empty