di_in_elm_5.elm

executeWith : String -> ScoresTagger msg -> Score -> Cmd msg
executeWith uri tagger score =
  let
    tagHighScores = highScoreTagger tagger
    storeScore = storeScoreTask uri
    getScores = getScoresTask uri
  in
    storeScore score
      |> Task.andThen (\_ -> getScores)
      |> Task.attempt tagHighScores

storeScoreTask : String -> Score -> Task Http.Error ()
storeScoreTask uri score =
  Http.post uri (Http.jsonBody <| encode score) (Json.succeed ())
    |> Http.toTask
    |> Task.onError (\_ -> Task.succeed ())

getScoresTask : String -> Task Http.Error (List Score)
getScoresTask uri =
  Http.get uri (Json.list scoreDecoder)
    |> Http.toTask

highScoreTagger : ScoresTagger msg -> Result Http.Error (List Score) -> msg
highScoreTagger tagger result =
  case result of
    Ok scores ->
      tagger scores
    Err _ ->
      tagger []

scoreDecoder : Decoder Score
decoder =
  Json.field "score" Json.int

encode : Score -> Value
encode score =
  Encode.object
    [ ( "score", Encode.int score )
    ]