Update intro/part8

intro/part8/src/Article/Feed.elm

@@ -2,11 +2,12 @@ module Article.Feed
     exposing
         ( Model
         , Msg
+        , decoder
         , init
-        , selectTag
         , update
         , viewArticles
-        , viewFeedSources
+        , viewPagination
+        , viewTabs
         )
 
 import Api
@@ -16,12 +17,11 @@ import Article.Slug as ArticleSlug exposing (Slug)
 import Article.Tag as Tag exposing (Tag)
 import Author
 import Avatar exposing (Avatar)
-import Browser.Dom as Dom
 import Html exposing (..)
 import Html.Attributes exposing (attribute, class, classList, href, id, placeholder, src)
 import Html.Events exposing (onClick)
 import Http
-import HttpBuilder exposing (RequestBuilder, withExpect, withQueryParams)
+import HttpBuilder exposing (RequestBuilder)
 import Json.Decode as Decode exposing (Decoder)
 import Json.Decode.Pipeline exposing (required)
 import Page
@@ -32,6 +32,7 @@ import Session exposing (Session)
 import Task exposing (Task)
 import Time
 import Timestamp
+import Url exposing (Url)
 import Username exposing (Username)
 import Viewer exposing (Viewer)
 import Viewer.Cred as Cred exposing (Cred)
@@ -59,37 +60,29 @@ overkill, so we use simpler APIs instead.
 
 
 type Model
-    = Model InternalModel
+    = Model Internals
 
 
 {-| This should not be exposed! We want to benefit from the guarantee that only
 this module can create or alter this model. This way if it ever ends up in
 a surprising state, we know exactly where to look: this module.
 -}
-type alias InternalModel =
+type alias Internals =
     { session : Session
     , errors : List String
     , articles : PaginatedList (Article Preview)
-    , sources : FeedSources
     , isLoading : Bool
     }
 
 
-init : Session -> FeedSources -> Task Http.Error Model
+init : Session -> PaginatedList (Article Preview) -> Model
-init session sources =
+init session articles =
-    let
+    Model
-        fromArticles articles =
+        { session = session
-            Model
+        , errors = []
-                { session = session
+        , articles = articles
-                , errors = []
+        , isLoading = False
-                , articles = articles
+        }
-                , sources = sources
-                , isLoading = False
-                }
-    in
-    FeedSources.selected sources
-        |> fetch (Session.cred session) 1
-        |> Task.map fromArticles
 
 
 
@@ -97,7 +90,7 @@ init session sources =
 
 
 viewArticles : Time.Zone -> Model -> List (Html Msg)
-viewArticles timeZone (Model { articles, sources, session }) =
+viewArticles timeZone (Model { articles, session, errors }) =
     let
         maybeCred =
             Session.cred session
@@ -105,14 +98,8 @@ viewArticles timeZone (Model { articles, sources, session }) =
         articlesHtml =
             PaginatedList.values articles
                 |> List.map (viewPreview maybeCred timeZone)
-
-        feedSource =
-            FeedSources.selected sources
-
-        pagination =
-            PaginatedList.view ClickedFeedPage articles (limit feedSource)
     in
-    List.append articlesHtml [ pagination ]
+    Page.viewErrors ClickedDismissErrors errors :: articlesHtml
 
 
 viewPreview : Maybe Cred -> Time.Zone -> Article Preview -> Html Msg
@@ -167,85 +154,43 @@ viewPreview maybeCred timeZone article =
             [ h1 [] [ text title ]
             , p [] [ text description ]
             , span [] [ text "Read more..." ]
+            , ul [ class "tag-list" ]
+                (List.map viewTag (Article.metadata article).tags)
             ]
         ]
 
 
-viewFeedSources : Model -> Html Msg
+viewTabs :
-viewFeedSources (Model { sources, isLoading, errors }) =
+    List ( String, msg )
-    let
+    -> ( String, msg )
-        errorsHtml =
+    -> List ( String, msg )
-            Page.viewErrors ClickedDismissErrors errors
+    -> Html msg
-    in
+viewTabs before selected after =
     ul [ class "nav nav-pills outline-active" ] <|
         List.concat
-            [ List.map (viewFeedSource False) (FeedSources.before sources)
+            [ List.map (viewTab []) before
-            , [ viewFeedSource True (FeedSources.selected sources) ]
+            , [ viewTab [ class "active" ] selected ]
-            , List.map (viewFeedSource False) (FeedSources.after sources)
+            , List.map (viewTab []) after
-            , [ errorsHtml ]
             ]
 
 
-viewFeedSource : Bool -> Source -> Html Msg
+viewTab : List (Attribute msg) -> ( String, msg ) -> Html msg
-viewFeedSource isSelected source =
+viewTab attrs ( name, msg ) =
     li [ class "nav-item" ]
-        [ a
+        [ -- Note: The RealWorld CSS requires an href to work properly.
-            [ classList [ ( "nav-link", True ), ( "active", isSelected ) ]
+          a (class "nav-link" :: onClick msg :: href "" :: attrs)
-            , onClick (ClickedFeedSource source)
+            [ text name ]
-
-            -- The RealWorld CSS requires an href to work properly.
-            , href ""
-            ]
-            [ text (sourceName source) ]
         ]
 
 
-selectTag : Maybe Cred -> Tag -> Cmd Msg
+viewPagination : (Int -> msg) -> Model -> Html msg
-selectTag maybeCred tag =
+viewPagination toMsg (Model feed) =
-    let
+    PaginatedList.view toMsg feed.articles
-        source =
-            TagFeed tag
-    in
-    fetch maybeCred 1 source
-        |> Task.attempt (CompletedFeedLoad source)
 
 
-sourceName : Source -> String
+viewTag : String -> Html msg
-sourceName source =
+viewTag tagName =
-    case source of
+    li [ class "tag-default tag-pill tag-outline" ] [ text tagName ]
-        YourFeed _ ->
-            "Your Feed"
-
-        GlobalFeed ->
-            "Global Feed"
-
-        TagFeed tagName ->
-            "#" ++ Tag.toString tagName
-
-        FavoritedFeed username ->
-            "Favorited Articles"
-
-        AuthorFeed username ->
-            "My Articles"
-
-
-limit : Source -> Int
-limit feedSource =
-    case feedSource of
-        YourFeed _ ->
-            10
-
-        GlobalFeed ->
-            10
-
-        TagFeed tagName ->
-            10
-
-        FavoritedFeed username ->
-            5
-
-        AuthorFeed username ->
-            5
 
 
 
@@ -256,10 +201,7 @@ type Msg
     = ClickedDismissErrors
     | ClickedFavorite Cred Slug
     | ClickedUnfavorite Cred Slug
-    | ClickedFeedPage Int
-    | ClickedFeedSource Source
     | CompletedFavorite (Result Http.Error (Article Preview))
-    | CompletedFeedLoad Source (Result Http.Error (PaginatedList (Article Preview)))
 
 
 update : Maybe Cred -> Msg -> Model -> ( Model, Cmd Msg )
@@ -268,32 +210,6 @@ update maybeCred msg (Model model) =
         ClickedDismissErrors ->
             ( Model { model | errors = [] }, Cmd.none )
 
-        ClickedFeedSource source ->
-            ( Model { model | isLoading = True }
-            , source
-                |> fetch maybeCred 1
-                |> Task.attempt (CompletedFeedLoad source)
-            )
-
-        CompletedFeedLoad source (Ok articles) ->
-            ( Model
-                { model
-                    | articles = articles
-                    , sources = FeedSources.select source model.sources
-                    , isLoading = False
-                }
-            , Cmd.none
-            )
-
-        CompletedFeedLoad _ (Err error) ->
-            ( Model
-                { model
-                    | errors = Api.addServerError model.errors
-                    , isLoading = False
-                }
-            , Cmd.none
-            )
-
         ClickedFavorite cred slug ->
             fave Article.favorite cred slug model
 
@@ -310,72 +226,6 @@ update maybeCred msg (Model model) =
             , Cmd.none
             )
 
-        ClickedFeedPage page ->
-            let
-                source =
-                    FeedSources.selected model.sources
-            in
-            ( Model model
-            , fetch maybeCred page source
-                |> Task.andThen (\articles -> Task.map (\_ -> articles) scrollToTop)
-                |> Task.attempt (CompletedFeedLoad source)
-            )
-
-
-scrollToTop : Task x ()
-scrollToTop =
-    Dom.setViewport 0 0
-        -- It's not worth showing the user anything special if scrolling fails.
-        -- If anything, we'd log this to an error recording service.
-        |> Task.onError (\_ -> Task.succeed ())
-
-
-fetch : Maybe Cred -> Int -> Source -> Task Http.Error (PaginatedList (Article Preview))
-fetch maybeCred page feedSource =
-    let
-        articlesPerPage =
-            limit feedSource
-
-        offset =
-            (page - 1) * articlesPerPage
-
-        params =
-            [ ( "limit", String.fromInt articlesPerPage )
-            , ( "offset", String.fromInt offset )
-            ]
-    in
-    Task.map (PaginatedList.mapPage (\_ -> page)) <|
-        case feedSource of
-            YourFeed cred ->
-                params
-                    |> buildFromQueryParams (Just cred) (Api.url [ "articles", "feed" ])
-                    |> Cred.addHeader cred
-                    |> HttpBuilder.toRequest
-                    |> Http.toTask
-
-            GlobalFeed ->
-                list maybeCred params
-
-            TagFeed tagName ->
-                list maybeCred (( "tag", Tag.toString tagName ) :: params)
-
-            FavoritedFeed username ->
-                list maybeCred (( "favorited", Username.toString username ) :: params)
-
-            AuthorFeed username ->
-                list maybeCred (( "author", Username.toString username ) :: params)
-
-
-list :
-    Maybe Cred
-    -> List ( String, String )
-    -> Task Http.Error (PaginatedList (Article Preview))
-list maybeCred params =
-    buildFromQueryParams maybeCred (Api.url [ "articles" ]) params
-        |> Cred.addHeaderIfAvailable maybeCred
-        |> HttpBuilder.toRequest
-        |> Http.toTask
-
 
 replaceArticle : Article a -> Article a -> Article a
 replaceArticle newArticle oldArticle =
@@ -390,29 +240,24 @@ replaceArticle newArticle oldArticle =
 -- SERIALIZATION
 
 
-decoder : Maybe Cred -> Decoder (PaginatedList (Article Preview))
+decoder : Maybe Cred -> Int -> Decoder (PaginatedList (Article Preview))
-decoder maybeCred =
+decoder maybeCred resultsPerPage =
     Decode.succeed PaginatedList.fromList
-        |> required "articlesCount" Decode.int
+        |> required "articlesCount" (pageCountDecoder resultsPerPage)
         |> required "articles" (Decode.list (Article.previewDecoder maybeCred))
 
 
-
+pageCountDecoder : Int -> Decoder Int
--- REQUEST
+pageCountDecoder resultsPerPage =
-
+    Decode.int
-
+        |> Decode.map (\total -> ceiling (toFloat total / toFloat resultsPerPage))
-buildFromQueryParams : Maybe Cred -> String -> List ( String, String ) -> RequestBuilder (PaginatedList (Article Preview))
-buildFromQueryParams maybeCred url queryParams =
-    HttpBuilder.get url
-        |> withExpect (Http.expectJson (decoder maybeCred))
-        |> withQueryParams queryParams
 
 
 
 -- INTERNAL
 
 
-fave : (Slug -> Cred -> Http.Request (Article Preview)) -> Cred -> Slug -> InternalModel -> ( Model, Cmd Msg )
+fave : (Slug -> Cred -> Http.Request (Article Preview)) -> Cred -> Slug -> Internals -> ( Model, Cmd Msg )
 fave toRequest cred slug model =
     ( Model model
     , toRequest slug cred

intro/part8/src/Page/Home.elm

@@ -3,20 +3,25 @@ module Page.Home exposing (Model, Msg, init, subscriptions, toSession, update, v
 {-| The homepage. You can get here via either the / or /#/ routes.
 -}
 
-import Article
+import Api
+import Article exposing (Article, Preview)
 import Article.Feed as Feed
 import Article.FeedSources as FeedSources exposing (FeedSources, Source(..))
 import Article.Tag as Tag exposing (Tag)
+import Browser.Dom as Dom
 import Html exposing (..)
 import Html.Attributes exposing (attribute, class, classList, href, id, placeholder)
 import Html.Events exposing (onClick)
 import Http
+import HttpBuilder
 import Loading
 import Log
 import Page
+import PaginatedList exposing (PaginatedList)
 import Session exposing (Session)
 import Task exposing (Task)
 import Time
+import Username exposing (Username)
 import Viewer.Cred as Cred exposing (Cred)
 
 
@@ -27,6 +32,8 @@ import Viewer.Cred as Cred exposing (Cred)
 type alias Model =
     { session : Session
     , timeZone : Time.Zone
+    , feedTab : FeedTab
+    , feedPage : Int
 
     -- Loaded independently from server
     , tags : Status (List Tag)
@@ -41,28 +48,35 @@ type Status a
     | Failed
 
 
+type FeedTab
+    = YourFeed Cred
+    | GlobalFeed
+    | TagFeed Tag
+
+
 init : Session -> ( Model, Cmd Msg )
 init session =
     let
-        feedSources =
+        feedTab =
             case Session.cred session of
                 Just cred ->
-                    FeedSources.fromLists (YourFeed cred) [ GlobalFeed ]
+                    YourFeed cred
 
                 Nothing ->
-                    FeedSources.fromLists GlobalFeed []
+                    GlobalFeed
 
         loadTags =
-            Tag.list
+            Http.toTask Tag.list
-                |> Http.toTask
     in
     ( { session = session
       , timeZone = Time.utc
+      , feedTab = feedTab
+      , feedPage = 1
       , tags = Loading
       , feed = Loading
       }
     , Cmd.batch
-        [ Feed.init session feedSources
+        [ fetchFeed session feedTab 1
             |> Task.attempt CompletedFeedLoad
         , Tag.list
             |> Http.send CompletedTagsLoad
@@ -87,7 +101,17 @@ view model =
                     [ div [ class "col-md-9" ] <|
                         case model.feed of
                             Loaded feed ->
-                                viewFeed model.timeZone feed
+                                [ div [ class "feed-toggle" ] <|
+                                    List.concat
+                                        [ [ viewTabs
+                                                (Session.cred model.session)
+                                                model.feedTab
+                                          ]
+                                        , Feed.viewArticles model.timeZone feed
+                                            |> List.map (Html.map GotFeedMsg)
+                                        , [ Feed.viewPagination ClickedFeedPage feed ]
+                                        ]
+                                ]
 
                             Loading ->
                                 []
@@ -130,11 +154,58 @@ viewBanner =
         ]
 
 
-viewFeed : Time.Zone -> Feed.Model -> List (Html Msg)
+
-viewFeed timeZone feed =
+-- TABS
-    div [ class "feed-toggle" ]
+
-        [ Feed.viewFeedSources feed |> Html.map GotFeedMsg ]
+
-        :: (Feed.viewArticles timeZone feed |> List.map (Html.map GotFeedMsg))
+viewTabs : Maybe Cred -> FeedTab -> Html Msg
+viewTabs maybeCred tab =
+    case tab of
+        YourFeed cred ->
+            Feed.viewTabs [] (yourFeed cred) [ globalFeed ]
+
+        GlobalFeed ->
+            let
+                otherTabs =
+                    case maybeCred of
+                        Just cred ->
+                            [ yourFeed cred ]
+
+                        Nothing ->
+                            []
+            in
+            Feed.viewTabs otherTabs globalFeed []
+
+        TagFeed tag ->
+            let
+                otherTabs =
+                    case maybeCred of
+                        Just cred ->
+                            [ yourFeed cred, globalFeed ]
+
+                        Nothing ->
+                            [ globalFeed ]
+            in
+            Feed.viewTabs otherTabs (tagFeed tag) []
+
+
+yourFeed : Cred -> ( String, Msg )
+yourFeed cred =
+    ( "Your Feed", ClickedTab (YourFeed cred) )
+
+
+globalFeed : ( String, Msg )
+globalFeed =
+    ( "Global Feed", ClickedTab GlobalFeed )
+
+
+tagFeed : Tag -> ( String, Msg )
+tagFeed tag =
+    ( "#" ++ Tag.toString tag, ClickedTab (TagFeed tag) )
+
+
+
+-- TAGS
 
 
 viewTags : List Tag -> Html Msg
@@ -160,6 +231,8 @@ viewTag tagName =
 
 type Msg
     = ClickedTag Tag
+    | ClickedTab FeedTab
+    | ClickedFeedPage Int
     | CompletedFeedLoad (Result Http.Error Feed.Model)
     | CompletedTagsLoad (Result Http.Error (List Tag))
     | GotTimeZone Time.Zone
@@ -171,12 +244,28 @@ type Msg
 update : Msg -> Model -> ( Model, Cmd Msg )
 update msg model =
     case msg of
-        ClickedTag tagName ->
+        ClickedTag tag ->
             let
-                subCmd =
+                feedTab =
-                    Feed.selectTag (Session.cred model.session) tagName
+                    TagFeed tag
             in
-            ( model, Cmd.map GotFeedMsg subCmd )
+            ( { model | feedTab = feedTab }
+            , fetchFeed model.session feedTab 1
+                |> Task.attempt CompletedFeedLoad
+            )
+
+        ClickedTab tab ->
+            ( { model | feedTab = tab }
+            , fetchFeed model.session tab 1
+                |> Task.attempt CompletedFeedLoad
+            )
+
+        ClickedFeedPage page ->
+            ( { model | feedPage = page }
+            , fetchFeed model.session model.feedTab page
+                |> Task.andThen (\feed -> Task.map (\_ -> feed) scrollToTop)
+                |> Task.attempt CompletedFeedLoad
+            )
 
         CompletedFeedLoad (Ok feed) ->
             ( { model | feed = Loaded feed }, Cmd.none )
@@ -242,6 +331,53 @@ update msg model =
 
 
 
+-- HTTP
+
+
+fetchFeed : Session -> FeedTab -> Int -> Task Http.Error Feed.Model
+fetchFeed session feedTabs page =
+    let
+        maybeCred =
+            Session.cred session
+
+        builder =
+            case feedTabs of
+                YourFeed cred ->
+                    Api.url [ "articles", "feed" ]
+                        |> HttpBuilder.get
+                        |> Cred.addHeader cred
+
+                GlobalFeed ->
+                    Api.url [ "articles" ]
+                        |> HttpBuilder.get
+                        |> Cred.addHeaderIfAvailable maybeCred
+
+                TagFeed tag ->
+                    Api.url [ "articles" ]
+                        |> HttpBuilder.get
+                        |> Cred.addHeaderIfAvailable maybeCred
+                        |> HttpBuilder.withQueryParam "tag" (Tag.toString tag)
+    in
+    builder
+        |> HttpBuilder.withExpect (Http.expectJson (Feed.decoder maybeCred articlesPerPage))
+        |> PaginatedList.fromRequestBuilder articlesPerPage page
+        |> Task.map (Feed.init session)
+
+
+articlesPerPage : Int
+articlesPerPage =
+    10
+
+
+scrollToTop : Task x ()
+scrollToTop =
+    Dom.setViewport 0 0
+        -- It's not worth showing the user anything special if scrolling fails.
+        -- If anything, we'd log this to an error recording service.
+        |> Task.onError (\_ -> Task.succeed ())
+
+
+
 -- SUBSCRIPTIONS
 
 

intro/part8/src/Page/Profile.elm

@@ -3,6 +3,8 @@ module Page.Profile exposing (Model, Msg, init, subscriptions, toSession, update
 {-| An Author's profile.
 -}
 
+import Api
+import Article exposing (Article, Preview)
 import Article.Feed as Feed
 import Article.FeedSources as FeedSources exposing (FeedSources, Source(..))
 import Author exposing (Author(..), FollowedAuthor, UnfollowedAuthor)
@@ -10,9 +12,11 @@ import Avatar exposing (Avatar)
 import Html exposing (..)
 import Html.Attributes exposing (..)
 import Http
+import HttpBuilder exposing (RequestBuilder)
 import Loading
 import Log
 import Page
+import PaginatedList exposing (PaginatedList)
 import Profile exposing (Profile)
 import Route
 import Session exposing (Session)
@@ -31,6 +35,8 @@ type alias Model =
     { session : Session
     , timeZone : Time.Zone
     , errors : List String
+    , feedTab : FeedTab
+    , feedPage : Int
 
     -- Loaded independently from server
     , author : Status Author
@@ -38,6 +44,11 @@ type alias Model =
     }
 
 
+type FeedTab
+    = MyArticles
+    | FavoritedArticles
+
+
 type Status a
     = Loading Username
     | LoadingSlowly Username
@@ -54,6 +65,8 @@ init session username =
     ( { session = session
       , timeZone = Time.utc
       , errors = []
+      , feedTab = defaultFeedTab
+      , feedPage = 1
       , author = Loading username
       , feed = Loading username
       }
@@ -62,16 +75,68 @@ init session username =
             |> Http.toTask
             |> Task.mapError (Tuple.pair username)
             |> Task.attempt CompletedAuthorLoad
-        , defaultFeedSources username
+        , fetchFeed session defaultFeedTab username 1
-            |> Feed.init session
-            |> Task.mapError (Tuple.pair username)
-            |> Task.attempt CompletedFeedLoad
         , Task.perform GotTimeZone Time.here
         , Task.perform (\_ -> PassedSlowLoadThreshold) Loading.slowThreshold
         ]
     )
 
 
+currentUsername : Model -> Username
+currentUsername model =
+    case model.author of
+        Loading username ->
+            username
+
+        LoadingSlowly username ->
+            username
+
+        Loaded author ->
+            Author.username author
+
+        Failed username ->
+            username
+
+
+defaultFeedTab : FeedTab
+defaultFeedTab =
+    MyArticles
+
+
+
+-- HTTP
+
+
+fetchFeed : Session -> FeedTab -> Username -> Int -> Cmd Msg
+fetchFeed session feedTabs username page =
+    let
+        maybeCred =
+            Session.cred session
+
+        ( extraParamName, extraParamVal ) =
+            case feedTabs of
+                MyArticles ->
+                    ( "author", Username.toString username )
+
+                FavoritedArticles ->
+                    ( "favorited", Username.toString username )
+    in
+    Api.url [ "articles" ]
+        |> HttpBuilder.get
+        |> HttpBuilder.withExpect (Http.expectJson (Feed.decoder maybeCred articlesPerPage))
+        |> HttpBuilder.withQueryParam extraParamName extraParamVal
+        |> Cred.addHeaderIfAvailable maybeCred
+        |> PaginatedList.fromRequestBuilder articlesPerPage page
+        |> Task.map (Feed.init session)
+        |> Task.mapError (Tuple.pair username)
+        |> Task.attempt CompletedFeedLoad
+
+
+articlesPerPage : Int
+articlesPerPage =
+    5
+
+
 
 -- VIEW
 
@@ -145,7 +210,13 @@ view model =
                     , case model.feed of
                         Loaded feed ->
                             div [ class "container" ]
-                                [ div [ class "row" ] [ viewFeed model.timeZone feed ] ]
+                                [ div [ class "row" ]
+                                    [ div [ class "col-xs-12 col-md-10 offset-md-1" ] <|
+                                        div [ class "articles-toggle" ]
+                                            [ viewTabs model.feedTab ]
+                                            :: (Feed.viewArticles model.timeZone feed |> List.map (Html.map GotFeedMsg))
+                                    ]
+                                ]
 
                         Loading _ ->
                             text ""
@@ -202,15 +273,27 @@ defaultTitle =
 
 
 
--- FEED
+-- TABS
 
 
-viewFeed : Time.Zone -> Feed.Model -> Html Msg
+viewTabs : FeedTab -> Html Msg
-viewFeed timeZone feed =
+viewTabs tab =
-    div [ class "col-xs-12 col-md-10 offset-md-1" ] <|
+    case tab of
-        div [ class "articles-toggle" ]
+        MyArticles ->
-            [ Feed.viewFeedSources feed |> Html.map GotFeedMsg ]
+            Feed.viewTabs [] myArticles [ favoritedArticles ]
-            :: (Feed.viewArticles timeZone feed |> List.map (Html.map GotFeedMsg))
+
+        FavoritedArticles ->
+            Feed.viewTabs [ myArticles ] favoritedArticles []
+
+
+myArticles : ( String, Msg )
+myArticles =
+    ( "My Articles", ClickedTab MyArticles )
+
+
+favoritedArticles : ( String, Msg )
+favoritedArticles =
+    ( "Favorited Articles", ClickedTab FavoritedArticles )
 
 
 
@@ -221,6 +304,7 @@ type Msg
     = ClickedDismissErrors
     | ClickedFollow Cred UnfollowedAuthor
     | ClickedUnfollow Cred FollowedAuthor
+    | ClickedTab FeedTab
     | CompletedFollowChange (Result Http.Error Author)
     | CompletedAuthorLoad (Result ( Username, Http.Error ) Author)
     | CompletedFeedLoad (Result ( Username, Http.Error ) Feed.Model)
@@ -248,6 +332,11 @@ update msg model =
                 |> Http.send CompletedFollowChange
             )
 
+        ClickedTab tab ->
+            ( { model | feedTab = tab }
+            , fetchFeed model.session tab (currentUsername model) 1
+            )
+
         CompletedFollowChange (Ok newAuthor) ->
             ( { model | author = Loaded newAuthor }
             , Cmd.none
@@ -335,12 +424,3 @@ subscriptions model =
 toSession : Model -> Session
 toSession model =
     model.session
-
-
-
--- INTERNAL
-
-
-defaultFeedSources : Username -> FeedSources
-defaultFeedSources username =
-    FeedSources.fromLists (AuthorFeed username) [ FavoritedFeed username ]

intro/part8/src/PaginatedList.elm

@@ -1,8 +1,11 @@
-module PaginatedList exposing (PaginatedList, fromList, map, mapPage, page, total, values, view)
+module PaginatedList exposing (PaginatedList, fromList, fromRequestBuilder, map, page, total, values, view)
 
 import Html exposing (Html, a, li, text, ul)
 import Html.Attributes exposing (class, classList, href)
 import Html.Events exposing (onClick)
+import Http
+import HttpBuilder exposing (RequestBuilder)
+import Task exposing (Task)
 
 
 
@@ -54,29 +57,18 @@ map transform (PaginatedList info) =
     PaginatedList { info | values = List.map transform info.values }
 
 
-mapPage : (Int -> Int) -> PaginatedList a -> PaginatedList a
-mapPage transform (PaginatedList info) =
-    PaginatedList { info | page = transform info.page }
-
-
 
 -- VIEW
 
 
-view : (Int -> msg) -> PaginatedList a -> Int -> Html msg
+view : (Int -> msg) -> PaginatedList a -> Html msg
-view toMsg list resultsPerPage =
+view toMsg (PaginatedList info) =
     let
-        totalPages =
-            ceiling (toFloat (total list) / toFloat resultsPerPage)
-
-        activePage =
-            page list
-
         viewPageLink currentPage =
-            pageLink toMsg currentPage (currentPage == activePage)
+            pageLink toMsg currentPage (currentPage == info.page)
     in
-    if totalPages > 1 then
+    if info.total > 1 then
-        List.range 1 totalPages
+        List.range 1 info.total
             |> List.map viewPageLink
             |> ul [ class "pagination" ]
 
@@ -96,3 +88,31 @@ pageLink toMsg targetPage isActive =
             ]
             [ text (String.fromInt targetPage) ]
         ]
+
+
+
+-- HTTP
+
+
+{-| I considered accepting a record here so I don't mess up the argument order.
+-}
+fromRequestBuilder :
+    Int
+    -> Int
+    -> RequestBuilder (PaginatedList a)
+    -> Task Http.Error (PaginatedList a)
+fromRequestBuilder resultsPerPage pageNumber builder =
+    let
+        offset =
+            (pageNumber - 1) * resultsPerPage
+
+        params =
+            [ ( "limit", String.fromInt resultsPerPage )
+            , ( "offset", String.fromInt offset )
+            ]
+    in
+    builder
+        |> HttpBuilder.withQueryParams params
+        |> HttpBuilder.toRequest
+        |> Http.toTask
+        |> Task.map (\(PaginatedList info) -> PaginatedList { info | page = pageNumber })