module Article exposing ( Article , Full , Preview , author , body , favorite , favoriteButton , fetch , fromPreview , fullDecoder , mapAuthor , metadata , previewDecoder , slug , unfavorite , unfavoriteButton , url ) {-| The interface to the Article data structure. This includes: - The Article type itself - Ways to make HTTP requests to retrieve and modify articles - Ways to access information about an article - Converting between various types -} import Api import Article.Body as Body exposing (Body) import Article.Slug as Slug exposing (Slug) import Article.Tag as Tag exposing (Tag) import Author exposing (Author) import Html exposing (Attribute, Html, i) import Html.Attributes exposing (class) import Html.Events exposing (stopPropagationOn) import Http import HttpBuilder exposing (RequestBuilder, withBody, withExpect, withQueryParams) import Json.Decode as Decode exposing (Decoder, bool, int, list, string) import Json.Decode.Pipeline exposing (custom, hardcoded, required) import Json.Encode as Encode import Markdown import Profile exposing (Profile) import Time import Timestamp import Username as Username exposing (Username) import Viewer exposing (Viewer) import Viewer.Cred as Cred exposing (Cred) -- TYPES {-| An article, optionally with an article body. To see the difference between { extraInfo : a } and { extraInfo : Maybe Body }, consider the difference between the "view individual article" page (which renders one article, including its body) and the "article feed" - which displays multiple articles, but without bodies. This definition for `Article` means we can write: viewArticle : Article Full -> Html msg viewFeed : List (Article Preview) -> Html msg This indicates that `viewArticle` requires an article _with a `body` present_, wereas `viewFeed` accepts articles with no bodies. (We could also have written it as `List (Article a)` to specify that feeds can accept either articles that have `body` present or not. Either work, given that feeds do not attempt to read the `body` field from articles.) This is an important distinction, because in Request.Article, the `feed` function produces `List (Article Preview)` because the API does not return bodies. Those articles are useful to the feed, but not to the individual article view. -} type Article a = Article Internals a type alias Internals = { slug : Slug , author : Author , metadata : Metadata } type Preview = Preview type Full = Full Body -- INFO author : Article a -> Author author (Article internals _) = internals.author metadata : Article a -> Metadata metadata (Article internals _) = internals.metadata slug : Article a -> Slug slug (Article internals _) = internals.slug body : Article Full -> Body body (Article _ (Full extraInfo)) = extraInfo -- TRANSFORM {-| This is the only way you can transform an existing article: you can change its author (e.g. to follow or unfollow them). All other article data necessarily comes from the server! We can tell this for sure by looking at the types of the exposed functions in this module. -} mapAuthor : (Author -> Author) -> Article a -> Article a mapAuthor transform (Article info extras) = Article { info | author = transform info.author } extras fromPreview : Body -> Article Preview -> Article Full fromPreview newBody (Article info Preview) = Article info (Full newBody) -- SERIALIZATION previewDecoder : Maybe Cred -> Decoder (Article Preview) previewDecoder maybeCred = Decode.succeed Article |> custom (internalsDecoder maybeCred) |> hardcoded Preview fullDecoder : Maybe Cred -> Decoder (Article Full) fullDecoder maybeCred = Decode.succeed Article |> custom (internalsDecoder maybeCred) |> required "body" (Decode.map Full Body.decoder) internalsDecoder : Maybe Cred -> Decoder Internals internalsDecoder maybeCred = Decode.succeed Internals |> required "slug" Slug.decoder |> required "author" (Author.decoder maybeCred) |> custom metadataDecoder type alias Metadata = { description : String , title : String , tags : List String , favorited : Bool , favoritesCount : Int , createdAt : Time.Posix } metadataDecoder : Decoder Metadata metadataDecoder = {- 👉 TODO: replace the calls to `hardcoded` with calls to `required` in order to decode these fields: --- "description" -------> description : String --- "title" -------------> title : String --- "tagList" -----------> tags : List String --- "favorited" ---------> favorited : Bool --- "favoritesCount" ----> favoritesCount : Int Once this is done, the articles in the feed should look normal again. 💡 HINT: Order matters! These must be decoded in the same order as the order of the fields in `type alias Metadata` above. ☝️ -} Decode.succeed Metadata |> hardcoded "(needs decoding!)" |> hardcoded "(needs decoding!)" |> hardcoded [] |> hardcoded False |> hardcoded 0 |> required "createdAt" Timestamp.iso8601Decoder -- SINGLE fetch : Maybe Cred -> Slug -> Http.Request (Article Full) fetch maybeCred articleSlug = let expect = fullDecoder maybeCred |> Decode.field "article" |> Http.expectJson in url articleSlug [] |> HttpBuilder.get |> HttpBuilder.withExpect expect |> Cred.addHeaderIfAvailable maybeCred |> HttpBuilder.toRequest -- FAVORITE favorite : Slug -> Cred -> Http.Request (Article Preview) favorite articleSlug cred = buildFavorite HttpBuilder.post articleSlug cred unfavorite : Slug -> Cred -> Http.Request (Article Preview) unfavorite articleSlug cred = buildFavorite HttpBuilder.delete articleSlug cred buildFavorite : (String -> RequestBuilder a) -> Slug -> Cred -> Http.Request (Article Preview) buildFavorite builderFromUrl articleSlug cred = let expect = previewDecoder (Just cred) |> Decode.field "article" |> Http.expectJson in builderFromUrl (url articleSlug [ "favorite" ]) |> Cred.addHeader cred |> withExpect expect |> HttpBuilder.toRequest {-| This is a "build your own element" API. You pass it some configuration, followed by a `List (Attribute msg)` and a `List (Html msg)`, just like any standard Html element. -} favoriteButton : Cred -> msg -> List (Attribute msg) -> List (Html msg) -> Html msg favoriteButton _ msg attrs kids = toggleFavoriteButton "btn btn-sm btn-outline-primary" msg attrs kids unfavoriteButton : Cred -> msg -> List (Attribute msg) -> List (Html msg) -> Html msg unfavoriteButton _ msg attrs kids = toggleFavoriteButton "btn btn-sm btn-primary" msg attrs kids toggleFavoriteButton : String -> msg -> List (Attribute msg) -> List (Html msg) -> Html msg toggleFavoriteButton classStr msg attrs kids = Html.button (class classStr :: onClickStopPropagation msg :: attrs) (i [ class "ion-heart" ] [] :: kids) onClickStopPropagation : msg -> Attribute msg onClickStopPropagation msg = stopPropagationOn "click" (Decode.succeed ( msg, True )) -- URLS url : Slug -> List String -> String url articleSlug paths = allArticlesUrl (Slug.toString articleSlug :: paths) allArticlesUrl : List String -> String allArticlesUrl paths = Api.url ("articles" :: paths)