module Data.Attoparsec.NBT where

import Prelude hiding (take)
import Control.Applicative hiding (empty)
import Control.Monad.Error
import Data.Attoparsec
import Data.Attoparsec.Combinator
import Data.Serialize.Get (runGet, getWord8, getWord16be, getWord32be, getWord64be)
import Data.NBT

data ParseError = ParseError String

type Fallible = Either ParseError

parseTag :: Parser (Fallible Tag)
parseTag =  parseEnd
        <|> parseByte
        <|> parseShort

parseEnd :: Parser (Fallible Tag)
parseEnd = do
    word8 0x00
    return $ Right TAG_End

parseByte :: Parser (Fallible Tag)
parseByte = do
    word8 0x01
    b <- anyWord8
    return $ Right (TAG_Byte $ fromIntegral b)

parseShort :: Parser (Fallible Tag)
parseShort = do
    word8 0x02
    s <- take 2
    case runGet getWord16be s of
        Left e -> return $ Left (ParseError "Failed to parse short.")
        Right a -> return $ Right (TAG_Short $ fromIntegral a)