module ElmHub exposing (..)

import Html exposing (..)
import Html.Attributes exposing (class, target, href, property, defaultValue)
import Html.Events exposing (..)
import Auth
import Json.Decode exposing (Decoder)
import Json.Decode.Pipeline exposing (..)


getQueryString : String -> String
getQueryString query =
    -- See https://developer.github.com/v3/search/#example for how to customize!
    "access_token="
        ++ Auth.token
        ++ "&q="
        ++ query
        ++ "+language:elm&sort=stars&order=desc"


responseDecoder : Decoder (List SearchResult)
responseDecoder =
    Json.Decode.at [ "items" ] (Json.Decode.list searchResultDecoder)


searchResultDecoder : Decoder SearchResult
searchResultDecoder =
    decode SearchResult
        |> required "id" Json.Decode.int
        |> required "full_name" Json.Decode.string
        |> required "stargazers_count" Json.Decode.int


type alias Model =
    { query : String
    , results : List SearchResult
    , errorMessage : Maybe String
    }


type alias SearchResult =
    { id : Int
    , name : String
    , stars : Int
    }


initialModel : Model
initialModel =
    { query = "tutorial"
    , results = []
    , errorMessage = Nothing
    }


view : Model -> Html Msg
view model =
    div [ class "content" ]
        [ header []
            [ h1 [] [ text "ElmHub" ]
            , span [ class "tagline" ] [ text "Like GitHub, but for Elm things." ]
            ]
        , input [ class "search-query", onInput SetQuery, defaultValue model.query ] []
        , button [ class "search-button", onClick Search ] [ text "Search" ]
        , viewErrorMessage model.errorMessage
        , ul [ class "results" ] (List.map viewSearchResult model.results)
        ]


viewErrorMessage : Maybe String -> Html a
viewErrorMessage errorMessage =
    case errorMessage of
        Just message ->
            div [ class "error" ] [ text message ]

        Nothing ->
            text ""


viewSearchResult : SearchResult -> Html Msg
viewSearchResult result =
    li []
        [ span [ class "star-count" ] [ text (toString result.stars) ]
        , a [ href ("https://github.com/" ++ result.name), target "_blank" ]
            [ text result.name ]
        , button [ class "hide-result", onClick (DeleteById result.id) ]
            [ text "X" ]
        ]


type Msg
    = Search
    | SetQuery String
    | DeleteById Int
    | HandleSearchResponse (List SearchResult)
    | HandleSearchError (Maybe String)


update : (String -> Cmd Msg) -> Msg -> Model -> ( Model, Cmd Msg )
update searchFeed msg model =
    case msg of
        Search ->
            ( model, searchFeed (getQueryString model.query) )

        SetQuery query ->
            ( { model | query = query }, Cmd.none )

        HandleSearchResponse results ->
            ( { model | results = results }, Cmd.none )

        HandleSearchError error ->
            ( { model | errorMessage = error }, Cmd.none )

        DeleteById idToDelete ->
            let
                newResults =
                    model.results
                        |> List.filter (\{ id } -> id /= idToDelete)

                newModel =
                    { model | results = newResults }
            in
                ( newModel, Cmd.none )


decodeGithubResponse : Json.Decode.Value -> Msg
decodeGithubResponse value =
    -- TODO use Json.Decode.DecodeValue to decode the response into a Msg.
    --
    -- Hint: look at the definition of Msg and
    -- the definition of responseDecoder
    HandleSearchError (Just "TODO decode the response!")