{-# LANGUAGE OverloadedStrings #-}
module Main where

import qualified Data.ASN1.BinaryEncoding as ASN1
import qualified Data.ASN1.Encoding       as ASN1
import qualified Data.ASN1.Error          as ASN1
import qualified Data.ASN1.Parse          as ASN1P
import qualified Data.ASN1.Types          as ASN1
import qualified Data.ByteString          as BS
import           Data.Maybe               (fromMaybe)
import           Debug.Trace              (trace)

-- import Hash2Pub.Fedichord

-- encoding values as ASN.1 types is done using Data.ASN1.Prim
someASN1 :: [ASN1.ASN1]
someASN1 = ASN1.Start ASN1.Sequence : ASN1.ASN1String (ASN1.asn1CharacterString ASN1.Visible domain) : ASN1.ASN1String (ASN1.asn1CharacterString ASN1.UTF8 unicode) : fmap ASN1.IntVal xs <> [ASN1.End ASN1.Sequence]
  where
    domain = "domains.are.ascii.on.ly"
    unicode = "Hähä, but unicode string!"
    xs = [ 23, 42, 2342 ]

asn1AsDer :: [ASN1.ASN1] -> BS.ByteString
asn1AsDer = ASN1.encodeASN1' ASN1.DER

derToAsn1 :: BS.ByteString -> Either ASN1.ASN1Error [ASN1.ASN1]
derToAsn1 = ASN1.decodeASN1' ASN1.DER

getUnicodeField :: [ASN1.ASN1] -> String
getUnicodeField (ASN1.Start ASN1.Sequence : _ : ASN1.ASN1String strASN1 : _) = fromMaybe "" $ ASN1.asn1CharacterToString strASN1

testParser :: ASN1P.ParseASN1 String
testParser = do
    foo <- ASN1P.onNextContainer ASN1.Sequence getAll
    pure $ show foo

getAll :: ASN1P.ParseASN1 [ASN1.ASN1]
getAll = ASN1P.getMany ASN1P.getNext

--stringParser asn1obj =
--    fmap (fromMaybe "" $ ASN1.asn1CharacterToString) ASN1P.getNext

main = do
    print someASN1
    print $ asn1AsDer someASN1
    print $ derToAsn1 . asn1AsDer $ someASN1
    putStrLn $ getUnicodeField someASN1
    print $ ASN1.decodeASN1Repr' ASN1.DER $ asn1AsDer someASN1
    putStrLn "\nLet's try a real parser combinator:"
    print $ ASN1P.runParseASN1State testParser someASN1