feat: Finish chapter 7

PhotoGroove/index.html

@@ -39,21 +39,7 @@
     <script src="http://elm-in-action.com/pasta.js"></script>
     <script src="app.js"></script> <!-- PhotoGroove.elm will get compiled into app.js --!>
     <script>
-      var app = Elm.PhotoGroove.init({
-        node: document.getElementById("app"),
-        flags: Pasta.version
-      }); // Elm object comes from app.js
-
-      app.ports.setFilters.subscribe(function(options) {
-        requestAnimationFrame(function() {
-           Pasta.apply(document.getElementById("main-canvas"), options);
-        });
-      });
-
-      Pasta.addActivityListener(function(activity) {
-        console.log("Got some activity to send to Elm:", activity);
-        app.ports.activityChanges.send(activity);
-      });
+      var app = Elm.PhotoFolders.init({ node: document.getElementById("app"), }); // Elm object comes from app.js
     </script>
   </body>
 </html>

PhotoGroove/src/PhotoFolders.elm

@@ -0,0 +1,258 @@
+module PhotoFolders exposing (main)
+
+import Browser
+import Dict exposing (Dict)
+import Html exposing (..)
+import Html.Attributes exposing (class, src)
+import Html.Events exposing (onClick)
+import Http
+import Json.Decode as Decode exposing (Decoder, int, list, string)
+import Json.Decode.Pipeline exposing (required)
+
+type Folder =
+    Folder
+        { name : String
+        , photoUrls : List String
+        , subfolders : List Folder
+        , expanded : Bool
+        }
+
+type alias Model =
+    { selectedPhotoUrl : Maybe String
+    , photos : Dict String Photo
+    , root : Folder
+    }
+
+initialModel : Model
+initialModel =
+    { selectedPhotoUrl = Nothing
+    , photos = Dict.empty
+    , root = Folder { name = "Loading...", expanded = True, photoUrls = [], subfolders = [] }
+    }
+
+init : () -> ( Model, Cmd Msg )
+init _ =
+    ( initialModel
+    , Http.get
+        { url = "http://elm-in-action.com/folders/list"
+        , expect = Http.expectJson GotInitialModel modelDecoder 
+        }
+    )
+
+modelDecoder : Decoder Model
+modelDecoder =
+    Decode.map2
+        (\photos root ->
+            { photos = photos, root = root, selectedPhotoUrl = Nothing }
+        )
+        modelPhotosDecoder
+        folderDecoder
+
+type Msg
+    = ClickedPhoto String
+    | GotInitialModel (Result Http.Error Model)
+    | ClickedFolder FolderPath
+
+update : Msg -> Model -> ( Model, Cmd Msg )
+update msg model =
+    case msg of
+        ClickedFolder path ->
+            ( { model | root = toggleExpanded path model.root }, Cmd.none )
+
+        ClickedPhoto url ->
+            ( { model | selectedPhotoUrl = Just url }, Cmd.none )
+
+        GotInitialModel (Ok newModel) ->
+            ( newModel, Cmd.none )
+
+        GotInitialModel (Err _) ->
+            ( model, Cmd.none  )
+
+view : Model -> Html Msg
+view model =
+    let
+        photoByUrl : String -> Maybe Photo
+        photoByUrl url =
+            Dict.get url model.photos
+
+        selectedPhoto : Html Msg
+        selectedPhoto =
+            case Maybe.andThen photoByUrl model.selectedPhotoUrl of
+                Just photo ->
+                    viewSelectedPhoto photo
+
+                Nothing ->
+                    text ""
+    in
+    div [ class "content" ]
+        [ div [ class "folders" ] 
+            [ h1 [] [ text "Folders" ]
+            , viewFolder End model.root
+            ]
+        , div [ class "selected-photo"] [ selectedPhoto ] 
+        ]
+
+main : Program () Model Msg
+main =
+    Browser.element
+        { init = init
+        , view = view
+        , update = update
+        , subscriptions = \_ -> Sub.none
+        }
+
+type alias Photo =
+    { title : String
+    , size : Int
+    , relatedUrls : List String
+    , url : String
+    }
+
+viewPhoto : String -> Html Msg
+viewPhoto url =
+    div [ class "photo", onClick (ClickedPhoto url) ]
+        [ text url ]
+
+viewSelectedPhoto : Photo -> Html Msg
+viewSelectedPhoto photo =
+    div
+        [ class "selected-photo" ]
+        [ h2 [] [ text photo.title]
+        , img [ src (urlPrefix ++ "photos/" ++ photo.url ++ "/full") ] []
+        , span [] [ text (String.fromInt photo.size ++ "KB") ]
+        , h3 [] [ text "Related" ]
+        , div [ class "related-photos" ]
+            (List.map viewRelatedPhoto photo.relatedUrls)
+        ]
+
+viewRelatedPhoto : String -> Html Msg
+viewRelatedPhoto url =
+    img
+        [ class "related-photo" 
+        , onClick (ClickedPhoto url)
+        , src (urlPrefix ++ "photos/" ++ url ++ "/thumb")
+        ]
+        []
+
+viewFolder : FolderPath -> Folder -> Html Msg
+viewFolder path (Folder folder) =
+    let
+        viewSubfolder : Int -> Folder -> Html Msg
+        viewSubfolder index subfolder =
+            viewFolder (appendIndex index path) subfolder
+
+        folderLabel =
+            label [ onClick (ClickedFolder path) ] [ text folder.name ]
+    in
+    if folder.expanded then
+        let
+            contents =
+                List.append
+                    (List.indexedMap viewSubfolder folder.subfolders)
+                    (List.map viewPhoto folder.photoUrls)
+        in
+        div [ class "folder expanded" ]
+            [ folderLabel
+            , div [ class "contents" ] contents
+            ]
+    else 
+        div [ class "folder collapsed" ] [ folderLabel ]
+
+appendIndex : Int -> FolderPath -> FolderPath
+appendIndex index path =
+    case path of
+        End ->
+            Subfolder index End
+
+        Subfolder subfolderIndex remainingPath ->
+            Subfolder subfolderIndex (appendIndex index remainingPath)
+
+urlPrefix : String
+urlPrefix =
+    "http://elm-in-action.com/"
+
+type FolderPath
+    = End
+    | Subfolder Int FolderPath
+
+toggleExpanded : FolderPath -> Folder -> Folder
+toggleExpanded path (Folder folder) =
+    case path of
+        End ->
+            Folder { folder | expanded = not folder.expanded }
+
+        Subfolder targetIndex remainingPath ->
+            let
+                subfolders : List Folder
+                subfolders =
+                    List.indexedMap transform folder.subfolders
+
+                transform : Int -> Folder -> Folder
+                transform currentIndex currentSubfolder =
+                    if currentIndex == targetIndex then
+                        toggleExpanded remainingPath currentSubfolder
+
+                    else
+                        currentSubfolder 
+            in
+            Folder { folder | subfolders = subfolders }
+
+type alias JsonPhoto =
+    { title : String
+    , size : Int
+    , relatedUrls : List String
+    }
+
+jsonPhotoDecoder : Decoder JsonPhoto
+jsonPhotoDecoder =
+    Decode.succeed JsonPhoto
+        |> required "title" string
+        |> required "size" int
+        |> required "related_photos" (list string)
+
+finishPhoto : ( String, JsonPhoto ) -> ( String, Photo )
+finishPhoto ( url, json ) =
+    ( url
+    , { url = url
+      , size = json.size
+      , title = json.title
+      , relatedUrls = json.relatedUrls
+      }
+    )
+
+fromPairs : List ( String, JsonPhoto ) -> Dict String Photo
+fromPairs pairs =
+    pairs
+        |> List.map finishPhoto
+        |> Dict.fromList
+
+photosDecoder : Decoder (Dict String Photo)
+photosDecoder =
+    Decode.keyValuePairs jsonPhotoDecoder
+        |> Decode.map fromPairs
+
+folderDecoder : Decoder Folder
+folderDecoder =
+    Decode.succeed folderFromJson
+        |> required "name" string
+        |> required "photos" photosDecoder
+        |> required "subfolders" (Decode.lazy (\_ -> list folderDecoder))
+
+folderFromJson : String -> Dict String Photo -> List Folder -> Folder
+folderFromJson name photos subfolders =
+    Folder 
+        { name = name
+        , expanded = True
+        , subfolders = subfolders
+        , photoUrls = Dict.keys photos
+        }
+
+modelPhotosDecoder : Decoder (Dict String Photo)
+modelPhotosDecoder =
+    Decode.succeed modelPhotosFromJson
+        |> required "photos" photosDecoder
+        |> required "subfolders" (Decode.lazy (\_ -> list modelPhotosDecoder))
+
+modelPhotosFromJson : Dict String Photo -> List (Dict String Photo) -> Dict String Photo
+modelPhotosFromJson folderPhotos subfolderPhotos =
+    List.foldl Dict.union folderPhotos subfolderPhotos