Elm HN Client

HackerNews.elm

module HackerNews exposing (..)

import Html exposing (..)
import Html.Attributes exposing (..)
import Http
import Json.Decode as Decode exposing (Decoder, field)


-- MODELS


type AppState
    = ViewingAll
    | Reading


type alias Model =
    { stories : List Story
    , appState : AppState
    , storyIds : List Int
    }


type alias Story =
    { by : String
    , descendants : Int
    , id : Int
    , kids : List Int
    , score : Int
    , time : Int
    , title : String
    , url : String
    }


initialModel : Model
initialModel =
    { stories =
        [ { by = "dhouston"
          , descendants = 71
          , id = 8863
          , kids = [ 8952, 9224, 8917, 8884, 8887, 8943, 8869, 8958, 9005, 9671, 8940, 9067, 8908, 9055, 8865, 8881, 8872, 8873, 8955, 10403, 8903, 8928, 9125, 8998, 8901, 8902, 8907, 8894, 8878, 8870, 8980, 8934, 8876 ]
          , score = 111
          , time = 1175714200
          , title = "My YC app: Dropbox - Throw away your USB drive"
          , url = "http://www.getdropbox.com/u/2/screencast.html"
          }
        , { by = "thelarkinn"
          , descendants = 257
          , id = 14779881
          , kids = []
          , score = 845
          , time = 1500165816
          , title = "Apache Foundation disallows use of the Facebook “BSD+Patent” license"
          , url = "https://issues.apache.org/jira/browse/LEGAL-303?focusedCommentId=16088663&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-16088663"
          }
        ]
    , appState = ViewingAll
    , storyIds = []
    }



-- API CONSTANTS


apiGetItem : Int -> String
apiGetItem id =
    "https://hacker-news.firebaseio.com/v0/item/" ++ (toString id) ++ ".json"


apiTopStoriesUrl : String
apiTopStoriesUrl =
    "https://hacker-news.firebaseio.com/v0/topstories.json"



-- UPDATES


type Msg
    = Top (Result Http.Error (List Int))
    | TopStories (Result Http.Error (List Story))


update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
    case msg of
        Top (Ok topStories) ->
            ( model, Cmd.batch (fetchTopStories topStories) )

        Top (Err error) ->
            let
                _ =
                    Debug.log "ERROR: " error
            in
                ( model, Cmd.none )

        TopStories (Ok allStories) ->
            let
                _ =
                    Debug.log "All Stories: " allStories
            in
                model ! [ Cmd.none ]

        TopStories (Err error) ->
            let
                _ =
                    Debug.log "ERROR: " error
            in
                model ! [ Cmd.none ]



-- DECODERS/ENCODERS


storyDecoder : Decoder Story
storyDecoder =
    Decode.map8 Story
        (field "by" Decode.string)
        (field "descendants" Decode.int)
        (field "id" Decode.int)
        (field "kids" (Decode.list Decode.int))
        (field "score" Decode.int)
        (field "time" Decode.int)
        (field "title" Decode.string)
        (field "url" Decode.string)



-- COMMANDS


fetchStoryById topStoryId =
    (Decode.list storyDecoder)
        |> Http.get (apiGetItem topStoryId)
        |> Http.send TopStories


fetchTopStories topStoriesIds =
    List.map fetchStoryById topStoriesIds


getTopStories : Cmd Msg
getTopStories =
    (Decode.list Decode.int)
        |> Http.get apiTopStoriesUrl
        |> Http.send Top



-- VIEW


viewHeader : Html msg
viewHeader =
    header []
        [ h1 [ class "h1" ] [ text "Hacker News" ]
        ]


viewFooter : Html msg
viewFooter =
    footer [ class "footer" ]
        [ div [ class "has-text-centered" ]
            [ p [] [ text "Visit ", a [ href "https://news.ycombinator.com/", target "_blank" ] [ text "Hacker News" ] ]
            , p [] [ text "Powered by ", a [ href "http://elm-lang.org/", target "_blank" ] [ text "Elm" ], text "." ]
            , p [] [ a [ href "https://github.com/dillonchanis", class "icon" ] [ i [ class "fa fa-github" ] [] ] ]
            ]
        ]


viewStoryPostInfo : Story -> Html msg
viewStoryPostInfo story =
    div []
        [ p [ class "text-muted" ]
            [ text ((toString story.score) ++ " points by ")
            , a [ href ("https://news.ycombinator.com/user?id=" ++ story.by) ] [ text story.by ]
            , span [ class "text-muted" ] [ text (" | " ++ (toString story.descendants) ++ " comments") ]
            ]
        ]


viewSingleStory : Story -> Html msg
viewSingleStory story =
    li [ class "story-item elevation" ]
        [ h2 [ class "h2" ] [ text story.title ]
        , viewStoryPostInfo story
        ]


viewStoryList : List Story -> Html msg
viewStoryList stories =
    let
        storyList =
            List.map viewSingleStory stories
    in
        ul [] storyList


view : Model -> Html msg
view model =
    div []
        [ section [ class "section" ]
            [ div [ class "container" ] [ viewHeader, viewStoryList model.stories, viewStory model.storyIds ] ]
        , viewFooter
        ]


init : ( Model, Cmd Msg )
init =
    ( initialModel, getTopStories )


main : Program Never Model Msg
main =
    Html.program
        { init = init
        , view = view
        , update = update
        , subscriptions = (always Sub.none)
        }