{-# LANGUAGE
    TypeOperators
  , UnicodeSyntax
  #-}
module Rakka.Attachment
    ( Attachment(..)
    )
    where
import Control.Arrow
import Control.Arrow.ArrowList
import Control.Arrow.ListArrow
import Control.Arrow.Unicode
import System.IO.Unsafe
import Text.XML.HXT.Arrow.ReadDocument
import Text.XML.HXT.Arrow.WriteDocument
import Text.XML.HXT.Arrow.XmlArrow
import Text.XML.HXT.Arrow.XmlState
import Text.XML.HXT.DOM.TypeDefs

class Attachment τ where
    serializeToXmlTree     ∷ (ArrowChoice (⇝), ArrowXml (⇝)) ⇒ τ ⇝ XmlTree
    deserializeFromXmlTree ∷ (ArrowChoice (⇝), ArrowXml (⇝)) ⇒ XmlTree ⇝ τ

    -- FIXME: String? Am I okay with that?
    serializeToString ∷ τ → String
    serializeToString attachment
        = do [xmlStr] ← runLA ( constA attachment
                                ⋙
                                serializeToXmlTree
                                ⋙
                                writeDocumentToString [ withIndent yes ]
                              ) ()
             return xmlStr

    deserializeFromString ∷ String → τ
    deserializeFromString source
        = unsafePerformIO $
          do [ret] ← runX ( setErrorMsgHandler False fail
                            ⋙
                            readString [ withValidate        no
                                       , withCheckNamespaces yes
                                       , withRemoveWS        yes
                                       ] source
                            ⋙
                            deserializeFromXmlTree
                          )
             return ret