updateRoute : Route -> Model -> (Model, List (Cmd msg))
updateRoute route model = (model, [Navigation.newUrl <| path route])

createPost: Model -> (Model, List (Cmd msg))
createPost model =
    let
        post = { id = List.length model.posts + 1 |> toString
               , title = model.form.postTitle
               , body = model.form.postBody }
    in
        ({ model | posts = (::) post model.posts}, [Cmd.none])

resetForm : Model -> (Model, List (Cmd msg))
resetForm model =
    ({model | form = { email = "", password = "", passwordAgain = "", postTitle = "", postBody = "" }}, [Cmd.none])

update: Msg -> Model -> (Model, Cmd Msg)
update msg model =
    case msg of
        OnLocationChange location ->
            ({model| route = parseLocation location}, [Cmd.none])
                |> andThen reroute
                |> Tuple.mapSecond batch

        UpdateRoute route ->
            updateRoute route model
                |> Tuple.mapSecond batch

        OnInput form ->
            ({ model | form = form }, Cmd.none)

        SignUp ->
            updateRoute LoginRoute model
                |> Tuple.mapSecond batch

        Login ->
            ({ model | user = Just { email = model.form.email }}, [Cmd.none])
                |> andThen resetForm
                |> andThen reroute
                |> Tuple.mapSecond batch

        Logout ->
            ({ model | user = Nothing }, [Cmd.none])
                |> andThen (updateRoute HomeRoute)
                |> Tuple.mapSecond batch

        CreatePost ->
            createPost model
                |> andThen resetForm
                |> andThen (updateRoute HomeRoute)
                |> Tuple.mapSecond batch