import Html.App exposing (beginnerProgram)
import Html exposing (text, div, button)
import Html.Events exposing (onClick)
import Json.Decode as Decode exposing ((:=), decodeString)


main =
    beginnerProgram
        { view = view
        , model = "Attempt to decode."
        , update = update
        }


type Msg
    = DecodeJson


update msg model =
    case msg of
        DecodeJson ->
            let
                decodedResult =
                    decodeString decoder faultyJsonString
            in
                model


view model =
    div []
        [ text faultyJsonString
        , button [ onClick DecodeJson ]
            [ text model ]
        ]


type Decoded
    = Decoded { id : Int, contained : List Decoded }


faultyJsonString =
    "{\"id\":1,\"contained\":[{\"id\":2,\"contained\":[{\"id\":3,\"contained\":[]}]}]}"


decoder =
    Decode.object2 (\id contained -> Decoded { id = id, contained = contained })
        ("id" := Decode.int)
        ("contained" := Decode.list decoder)