{-# LANGUAGE OverloadedStrings #-}
module Main where

import qualified Data.ASN1.Encoding as ASN1 -- asn1-encoding package
import qualified Data.ASN1.BinaryEncoding as ASN1
import qualified Data.ASN1.Error as ASN1
import qualified Data.ASN1.Types as ASN1 -- asn1-types package
import qualified Data.ASN1.Parse as ASN1P
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) : map 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
    return $ 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