Add part7

intro/part7/src/Page/Home.elm

@@ -0,0 +1,259 @@
+module Page.Home exposing (Model, Msg, init, subscriptions, toSession, update, view)
+
+{-| The homepage. You can get here via either the / or /#/ routes.
+-}
+
+import Article
+import Article.Feed as Feed
+import Article.FeedSources as FeedSources exposing (FeedSources, Source(..))
+import Article.Tag as Tag exposing (Tag)
+import Html exposing (..)
+import Html.Attributes exposing (attribute, class, classList, href, id, placeholder)
+import Html.Events exposing (onClick)
+import Http
+import Loading
+import Log
+import Page
+import Session exposing (Session)
+import Task exposing (Task)
+import Time
+import Viewer.Cred as Cred exposing (Cred)
+
+
+
+-- MODEL
+
+
+type alias Model =
+    { session : Session
+    , timeZone : Time.Zone
+
+    -- Loaded independently from server
+    , tags : Status (List Tag)
+    , feed : Status Feed.Model
+    }
+
+
+type Status a
+    = Loading
+    | LoadingSlowly
+    | Loaded a
+    | Failed
+
+
+init : Session -> ( Model, Cmd Msg )
+init session =
+    let
+        feedSources =
+            case Session.cred session of
+                Just cred ->
+                    FeedSources.fromLists (YourFeed cred) [ GlobalFeed ]
+
+                Nothing ->
+                    FeedSources.fromLists GlobalFeed []
+
+        loadTags =
+            Tag.list
+                |> Http.toTask
+    in
+    ( { session = session
+      , timeZone = Time.utc
+      , tags = Loading
+      , feed = Loading
+      }
+    , Cmd.batch
+        [ Feed.init session feedSources
+            |> Task.attempt CompletedFeedLoad
+        , Tag.list
+            |> Http.send CompletedTagsLoad
+        , Task.perform GotTimeZone Time.here
+        , Task.perform (\_ -> PassedSlowLoadThreshold) Loading.slowThreshold
+        ]
+    )
+
+
+
+-- VIEW
+
+
+view : Model -> { title : String, content : Html Msg }
+view model =
+    { title = "Conduit"
+    , content =
+        div [ class "home-page" ]
+            [ viewBanner
+            , div [ class "container page" ]
+                [ div [ class "row" ]
+                    [ div [ class "col-md-9" ] <|
+                        case model.feed of
+                            Loaded feed ->
+                                viewFeed model.timeZone feed
+
+                            Loading ->
+                                []
+
+                            LoadingSlowly ->
+                                [ Loading.icon ]
+
+                            Failed ->
+                                [ Loading.error "feed" ]
+                    , div [ class "col-md-3" ] <|
+                        case model.tags of
+                            Loaded tags ->
+                                [ div [ class "sidebar" ] <|
+                                    [ p [] [ text "Popular Tags" ]
+                                    , viewTags tags
+                                    ]
+                                ]
+
+                            Loading ->
+                                []
+
+                            LoadingSlowly ->
+                                [ Loading.icon ]
+
+                            Failed ->
+                                [ Loading.error "tags" ]
+                    ]
+                ]
+            ]
+    }
+
+
+viewBanner : Html msg
+viewBanner =
+    div [ class "banner" ]
+        [ div [ class "container" ]
+            [ h1 [ class "logo-font" ] [ text "conduit" ]
+            , p [] [ text "A place to share your knowledge." ]
+            ]
+        ]
+
+
+viewFeed : Time.Zone -> Feed.Model -> List (Html Msg)
+viewFeed timeZone feed =
+    div [ class "feed-toggle" ]
+        [ Feed.viewFeedSources feed |> Html.map GotFeedMsg ]
+        :: (Feed.viewArticles timeZone feed |> List.map (Html.map GotFeedMsg))
+
+
+viewTags : List Tag -> Html Msg
+viewTags tags =
+    div [ class "tag-list" ] (List.map viewTag tags)
+
+
+viewTag : Tag -> Html Msg
+viewTag tagName =
+    a
+        [ class "tag-pill tag-default"
+        , onClick (ClickedTag tagName)
+
+        -- The RealWorld CSS requires an href to work properly.
+        , href ""
+        ]
+        [ text (Tag.toString tagName) ]
+
+
+
+-- UPDATE
+
+
+type Msg
+    = ClickedTag Tag
+    | CompletedFeedLoad (Result Http.Error Feed.Model)
+    | CompletedTagsLoad (Result Http.Error (List Tag))
+    | GotTimeZone Time.Zone
+    | GotFeedMsg Feed.Msg
+    | GotSession Session
+    | PassedSlowLoadThreshold
+
+
+update : Msg -> Model -> ( Model, Cmd Msg )
+update msg model =
+    case msg of
+        ClickedTag tagName ->
+            let
+                subCmd =
+                    Feed.selectTag (Session.cred model.session) tagName
+            in
+            ( model, Cmd.map GotFeedMsg subCmd )
+
+        CompletedFeedLoad (Ok feed) ->
+            ( { model | feed = Loaded feed }, Cmd.none )
+
+        CompletedFeedLoad (Err error) ->
+            ( { model | feed = Failed }, Cmd.none )
+
+        CompletedTagsLoad (Ok tags) ->
+            ( { model | tags = Loaded tags }, Cmd.none )
+
+        CompletedTagsLoad (Err error) ->
+            ( { model | tags = Failed }
+            , Log.error
+            )
+
+        GotFeedMsg subMsg ->
+            case model.feed of
+                Loaded feed ->
+                    let
+                        ( newFeed, subCmd ) =
+                            Feed.update (Session.cred model.session) subMsg feed
+                    in
+                    ( { model | feed = Loaded newFeed }
+                    , Cmd.map GotFeedMsg subCmd
+                    )
+
+                Loading ->
+                    ( model, Log.error )
+
+                LoadingSlowly ->
+                    ( model, Log.error )
+
+                Failed ->
+                    ( model, Log.error )
+
+        GotTimeZone tz ->
+            ( { model | timeZone = tz }, Cmd.none )
+
+        GotSession session ->
+            ( { model | session = session }, Cmd.none )
+
+        PassedSlowLoadThreshold ->
+            let
+                -- If any data is still Loading, change it to LoadingSlowly
+                -- so `view` knows to render a spinner.
+                feed =
+                    case model.feed of
+                        Loading ->
+                            LoadingSlowly
+
+                        other ->
+                            other
+
+                tags =
+                    case model.tags of
+                        Loading ->
+                            LoadingSlowly
+
+                        other ->
+                            other
+            in
+            ( { model | feed = feed, tags = tags }, Cmd.none )
+
+
+
+-- SUBSCRIPTIONS
+
+
+subscriptions : Model -> Sub Msg
+subscriptions model =
+    Session.changes GotSession (Session.navKey model.session)
+
+
+
+-- EXPORT
+
+
+toSession : Model -> Session
+toSession model =
+    model.session