-- SPDX-FileCopyrightText: 2018 obsidian.systems
-- SPDX-FileCopyrightText: 2020 Tocqueville Group
--
-- SPDX-License-Identifier: LicenseRef-MIT-obsidian-systems

-- | Module that defines helper types and functions that are related
-- to Micheline.
module Morley.Micheline.Json
  ( StringEncode (..)
  , TezosBigNum
  , TezosInt64
  , TezosMutez (..)
  ) where

import Data.Aeson (FromJSON, ToJSON, parseJSON, toEncoding, toJSON)
import qualified Data.Aeson.Encoding as AE
import qualified Data.Aeson.Types as Aeson
import Data.Bits (Bits)
import Data.Typeable (typeRep)
import Fmt (Buildable(..))
import qualified Text.Show as T

import Tezos.Core (Mutez, mkMutez', mutezToInt64)

printAsString :: Show a => a -> Aeson.Value
printAsString a = Aeson.String $ show a

parseAsString :: forall a. (Read a, Typeable a) => Aeson.Value -> Aeson.Parser a
parseAsString = Aeson.withText (T.show $ typeRep (Proxy :: Proxy a)) $ \txt ->
  maybe (fail "Failed to parse string") pure $ readMaybe (toString txt)

parseStringEncodedIntegral :: (Read a, Typeable a) => Aeson.Value -> Aeson.Parser (StringEncode a)
parseStringEncodedIntegral x = StringEncode <$> parseAsString x

newtype StringEncode a = StringEncode { unStringEncode :: a }
  deriving stock (Generic, Eq, Ord, Bounded, Read, Show)
  deriving newtype (Enum, Num, Integral, Bits, Real, NFData, Hashable)

type TezosBigNum = StringEncode Integer

instance FromJSON TezosBigNum where
  parseJSON = parseStringEncodedIntegral

instance ToJSON TezosBigNum where
  toJSON (StringEncode x) = Aeson.String $ show x
  toEncoding (StringEncode x) = AE.integerText x

type TezosInt64 = StringEncode Int64

instance FromJSON TezosInt64 where
  parseJSON = parseStringEncodedIntegral

instance Buildable TezosInt64 where
  build = show

instance ToJSON TezosInt64 where
  toJSON (StringEncode x) = Aeson.String $ show x
  toEncoding (StringEncode x) = AE.int64Text x

newtype TezosMutez = TezosMutez { unTezosMutez :: Mutez }
  deriving stock (Show, Eq, Ord)

instance ToJSON TezosMutez where
  toJSON = printAsString . mutezToInt64 . unTezosMutez

instance FromJSON TezosMutez where
  parseJSON v = do
    i <- parseAsString @Int64 v
    either (fail . toString) (pure . TezosMutez) $ mkMutez' i