import Dict exposing (Dict)
import Html exposing (Html, div, text, input, ul, li)
import Html.Events exposing (..)
import Task exposing (Task)
import String

---------------------------

main =
  Html.program
    { init = init
    , view = view viewSuggestion
    , update = update getSuggestions
    , subscriptions = subscriptions
    }

---------------------------

data : List String
data =
  [ "Arizona"
  , "Arkansas"
  , "California"
  , "Colorado"
  , "Delaware"
  , "Florida"
  , "New York"
  , "New Jersey"
  , "Pennsylvania"
  , "Texas" ]

attemptedSuggestions : String -> Result String (List suggestion) -> Msg suggestion
attemptedSuggestions query result =
    case result of
        Ok suggestions ->
            AddSuggestions query suggestions
        Err _ ->
            NoOp

getSuggestions : String -> Task String (List String)
getSuggestions query =
  if String.trim query == ""
  then
    Task.fail "No Query"
  else
    (data
    |> List.filter (String.startsWith query)
    |> Task.succeed)


---------------------------

type alias Model suggestion =
  { cache : Dict String (List suggestion)
  , query : String
  }


type Msg suggestion
  = Query String
  | AddSuggestions String (List suggestion)
  | NoOp



init : (Model suggestion, Cmd (Msg suggestion))
init =
  ( { cache = Dict.empty
    , query = ""
    }
  , Cmd.none )


subscriptions : Model suggestion -> Sub (Msg suggestion)
subscriptions model =
  Sub.none


update : (String -> Task String (List suggestion))
      -> Msg suggestion
      -> Model suggestion
      -> (Model suggestion, Cmd (Msg suggestion))
update getSuggestions msg model =
  case msg of
    Query query ->
      let cmd =
        Task.attempt (attemptedSuggestions query) (getSuggestions query)
      in
        ( { model | query = query }
        , cmd )

    AddSuggestions query suggestions ->
      ( { model | cache = Dict.insert query suggestions model.cache }
      , Cmd.none )

    NoOp ->
      ( model
      , Cmd.none )


view : (suggestion -> Html (Msg suggestion)) -> Model suggestion -> Html (Msg suggestion)
view viewSuggestion model =
  let suggestions =
        case Dict.get model.query model.cache of
          Nothing ->
            []
          Just results ->
            results

  in
    div
      []
      [ input
          [ onInput Query ]
          [ ]

      , div
          []
          ( List.map viewSuggestion suggestions ) ]


viewSuggestion : String -> Html a
viewSuggestion suggestion =
  div
    []
    [ text suggestion ]