feat: Unit card previews [FC-0083]

src/library-authoring/components/BaseCard.scss

@@ -1,6 +1,7 @@
 .library-item-card {
   .pgn__card {
-    height: 100%
+    height: 100%;
+    min-width: 15rem;
   }
 
   .library-item-header {

src/library-authoring/components/BaseCard.tsx

@@ -17,6 +17,7 @@ type BaseCardProps = {
   itemType: string;
   displayName: string;
   description?: string;
+  preview?: React.ReactNode;
   numChildren?: number;
   tags: ContentHitTags;
   actions: React.ReactNode;
@@ -70,10 +71,10 @@ const BaseCard = ({
         />
         <Card.Body className="w-100">
           <Card.Section>
-            <div className="text-truncate h3 mt-2">
+            <div className="text-truncate h3 mt-1">
               <Highlight text={displayName} />
             </div>
-            <Highlight text={description} />
+            {props.preview || <Highlight text={description} />}
           </Card.Section>
         </Card.Body>
         <Card.Footer className="mt-auto">

src/library-authoring/components/ContainerCard.test.tsx

@@ -1,9 +1,10 @@
 import userEvent from '@testing-library/user-event';
 
 import {
-  initializeMocks, render as baseRender, screen,
+  initializeMocks, render as baseRender, screen, waitFor,
 } from '../../testUtils';
 import { LibraryProvider } from '../common/context/LibraryContext';
+import { mockContentLibrary, mockGetContainerChildren } from '../data/api.mocks';
 import { type ContainerHit, PublishStatus } from '../../search-manager';
 import ContainerCard from './ContainerCard';
 
@@ -33,6 +34,9 @@ const containerHitSample: ContainerHit = {
   publishStatus: PublishStatus.Published,
 };
 
+mockContentLibrary.applyMock();
+mockGetContainerChildren.applyMock();
+
 const render = (ui: React.ReactElement, showOnlyPublished: boolean = false) => baseRender(ui, {
   extraWrapper: ({ children }) => (
     <LibraryProvider
@@ -80,4 +84,37 @@ describe('<ContainerCard />', () => {
     //   '/library/lb:org1:Demo_Course/container/container-display-name-123',
     // );
   });
+
+  it('should render no child blocks in card preview', async () => {
+    render(<ContainerCard hit={containerHitSample} />);
+
+    expect(screen.queryByTitle('text block')).not.toBeInTheDocument();
+    expect(screen.queryByText('+0')).not.toBeInTheDocument();
+  });
+
+  it('should render <=5 child blocks in card preview', async () => {
+    const containerWith5Children = {
+      ...containerHitSample,
+      usageKey: mockGetContainerChildren.fiveChildren,
+    };
+    render(<ContainerCard hit={containerWith5Children} />);
+
+    await waitFor(() => {
+      expect(screen.getAllByTitle('text block').length).toBe(5);
+    });
+    expect(screen.queryByText('+0')).not.toBeInTheDocument();
+  });
+
+  it('should render >5 child blocks with +N in card preview', async () => {
+    const containerWith6Children = {
+      ...containerHitSample,
+      usageKey: mockGetContainerChildren.sixChildren,
+    };
+    render(<ContainerCard hit={containerWith6Children} />);
+
+    await waitFor(() => {
+      expect(screen.getAllByTitle('text block').length).toBe(4);
+    });
+    expect(screen.queryByText('+2')).toBeInTheDocument();
+  });
 });

src/library-authoring/components/ContainerCard.tsx

@@ -1,20 +1,23 @@
-import { useCallback } from 'react';
+import { ReactNode, useCallback } from 'react';
 import { FormattedMessage, useIntl } from '@edx/frontend-platform/i18n';
 import {
   ActionRow,
   Dropdown,
   Icon,
   IconButton,
+  Stack,
 } from '@openedx/paragon';
 import { MoreVert } from '@openedx/paragon/icons';
 import { Link } from 'react-router-dom';
 
+import { getItemIcon, getComponentStyleColor } from '../../generic/block-type-utils';
 import { type ContainerHit, PublishStatus } from '../../search-manager';
 import { useComponentPickerContext } from '../common/context/ComponentPickerContext';
 import { useLibraryContext } from '../common/context/LibraryContext';
 import { useSidebarContext } from '../common/context/SidebarContext';
-import { useLibraryRoutes } from '../routes';
 import BaseCard from './BaseCard';
+import { useContainerChildren } from '../data/apiHooks';
+import { useLibraryRoutes } from '../routes';
 import messages from './messages';
 
 type ContainerMenuProps = {
@@ -49,6 +52,59 @@ const ContainerMenu = ({ hit } : ContainerMenuProps) => {
   );
 };
 
+type ContainerCardPreviewProps = {
+  containerId: string;
+  showMaxChildren?: number;
+};
+
+const ContainerCardPreview = ({ containerId, showMaxChildren = 5 }: ContainerCardPreviewProps) => {
+  const { data, isLoading, isError } = useContainerChildren(containerId);
+  if (isLoading || isError) {
+    return null;
+  }
+
+  const hiddenChildren = data.length - showMaxChildren;
+  return (
+    <Stack direction="horizontal" gap={2}>
+      {
+        data.slice(0, showMaxChildren).map(({ id, blockType, displayName }, idx) => {
+          let blockPreview: ReactNode;
+          let classNames;
+
+          if (idx < showMaxChildren - 1 || hiddenChildren <= 0) {
+            // Show the first N-1 blocks as item icons
+            // (or all N blocks if no hidden children)
+            classNames = `rounded p-1 ${getComponentStyleColor(blockType)}`;
+            blockPreview = (
+              <Icon
+                src={getItemIcon(blockType)}
+                screenReaderText={blockType}
+                title={displayName}
+              />
+            );
+          } else {
+            // Container has more blocks than can fit in the preview, so show "+N"
+            blockPreview = (
+              <FormattedMessage
+                {...messages.containerPreviewMoreBlocks}
+                values={{ count: hiddenChildren + 1 }}
+              />
+            );
+          }
+          return (
+            <div
+              key={`container-card-preview-block-${id}`}
+              className={classNames}
+            >
+              {blockPreview}
+            </div>
+          );
+        })
+      }
+    </Stack>
+  );
+};
+
 type ContainerCardProps = {
   hit: ContainerHit,
 };
@@ -90,6 +146,7 @@ const ContainerCard = ({ hit } : ContainerCardProps) => {
     <BaseCard
       itemType={itemType}
       displayName={displayName}
+      preview={<ContainerCardPreview containerId={unitId} />}
       tags={tags}
       numChildren={numChildrenCount}
       actions={!componentPickerMode && (

src/library-authoring/components/messages.ts

@@ -176,5 +176,10 @@ const messages = defineMessages({
     defaultMessage: 'This component can be synced in courses after publish.',
     description: 'Alert text of the modal to confirm publish a component in a library.',
   },
+  containerPreviewMoreBlocks: {
+    id: 'course-authoring.library-authoring.component.container-card-preview.more-blocks',
+    defaultMessage: '+{count}',
+    description: 'Count shown when a container has more blocks than will fit on the card preview.',
+  },
 });
 export default messages;

src/library-authoring/data/api.mocks.ts

@@ -498,6 +498,56 @@ mockGetContainerMetadata.applyMock = () => {
   jest.spyOn(api, 'getContainerMetadata').mockImplementation(mockGetContainerMetadata);
 };
 
+/**
+ * Mock for `getContainerChildren()`
+ *
+ * This mock returns a fixed response for the given container ID.
+ */
+export async function mockGetContainerChildren(containerId: string): Promise<api.LibraryBlockMetadata[]> {
+  let numChildren: number;
+  switch (containerId) {
+    case mockGetContainerChildren.fiveChildren:
+      numChildren = 5;
+      break;
+    case mockGetContainerChildren.sixChildren:
+      numChildren = 6;
+      break;
+    default:
+      numChildren = 0;
+      break;
+  }
+  return Promise.resolve(
+    Array(numChildren).fill(mockGetContainerChildren.childTemplate).map((child, idx) => (
+      {
+        ...child,
+        // Generate a unique ID for each child block to avoid "duplicate key" errors in tests
+        id: `lb:org1:Demo_course:html:text-${idx}`,
+      }
+    )),
+  );
+}
+mockGetContainerChildren.fiveChildren = 'lct:org1:Demo_Course:unit:unit-5';
+mockGetContainerChildren.sixChildren = 'lct:org1:Demo_Course:unit:unit-6';
+mockGetContainerChildren.childTemplate = {
+  id: 'lb:org1:Demo_course:html:text',
+  blockType: 'html',
+  defKey: 'def_key',
+  displayName: 'text block',
+  lastPublished: null,
+  publishedBy: null,
+  lastDraftCreated: null,
+  lastDraftCreatedBy: null,
+  hasUnpublishedChanges: false,
+  created: null,
+  modified: null,
+  tagsCount: 0,
+  collections: [] as api.CollectionMetadata[],
+} satisfies api.LibraryBlockMetadata;
+/** Apply this mock. Returns a spy object that can tell you if it's been called. */
+mockGetContainerChildren.applyMock = () => {
+  jest.spyOn(api, 'getContainerChildren').mockImplementation(mockGetContainerChildren);
+};
+
 /**
  * Mock for `getXBlockOLX()`
  *

src/library-authoring/data/api.ts

@@ -111,6 +111,10 @@ export const getLibraryContainersApiUrl = (libraryId: string) => `${getApiBaseUr
  * Get the URL for the container detail api.
  */
 export const getLibraryContainerApiUrl = (containerId: string) => `${getApiBaseUrl()}/api/libraries/v2/containers/${containerId}/`;
+/**
+ * Get the URL for a single container children api.
+ */
+export const getLibraryContainerChildrenApiUrl = (containerId: string) => `${getLibraryContainerApiUrl(containerId)}children/`;
 
 export interface ContentLibrary {
   id: string;
@@ -616,3 +620,12 @@ export async function updateContainerMetadata(
   const client = getAuthenticatedHttpClient();
   await client.patch(getLibraryContainerApiUrl(containerId), snakeCaseObject(containerData));
 }
+
+/**
+ * Fetch a library container's children's metadata.
+ */
+export async function getContainerChildren(containerId: string): Promise<LibraryBlockMetadata[]> {
+  const client = getAuthenticatedHttpClient();
+  const { data } = await client.get(getLibraryContainerChildrenApiUrl(containerId));
+  return camelCaseObject(data);
+}

src/library-authoring/data/apiHooks.test.tsx

@@ -13,6 +13,7 @@ import {
   getLibraryCollectionApiUrl,
   getBlockTypesMetaDataUrl,
   getLibraryContainerApiUrl,
+  getLibraryContainerChildrenApiUrl,
 } from './api';
 import {
   useCommitLibraryChanges,
@@ -23,6 +24,7 @@ import {
   useCollection,
   useBlockTypesMetadata,
   useContainer,
+  useContainerChildren,
 } from './apiHooks';
 
 let axiosMock;
@@ -152,4 +154,79 @@ describe('library api hooks', () => {
     expect(result.current.data).toEqual({ testData: 'test-value' });
     expect(axiosMock.history.get[0].url).toEqual(url);
   });
+
+  it('should get container children', async () => {
+    const containerId = 'lct:lib:org:unit:unit1';
+    const url = getLibraryContainerChildrenApiUrl(containerId);
+
+    axiosMock.onGet(url).reply(200, [
+      {
+        id: 'lb:org1:Demo_course:html:text',
+        block_type: 'html',
+        def_key: 'def_key',
+        display_name: 'text block',
+        last_published: null,
+        published_by: null,
+        last_draft_created: null,
+        last_draft_created_by: null,
+        has_unpublished_changes: false,
+        created: null,
+        modified: null,
+        tags_count: 0,
+        collections: ['col1', 'col2'],
+      },
+      {
+        id: 'lb:org1:Demo_course:video:video1',
+        block_type: 'video',
+        def_key: 'def_key',
+        display_name: 'video block',
+        last_published: null,
+        published_by: null,
+        last_draft_created: null,
+        last_draft_created_by: null,
+        has_unpublished_changes: false,
+        created: null,
+        modified: null,
+        tags_count: 0,
+        collections: ['col2'],
+      },
+    ]);
+    const { result } = renderHook(() => useContainerChildren(containerId), { wrapper });
+    await waitFor(() => {
+      expect(result.current.isLoading).toBeFalsy();
+    });
+    expect(result.current.data).toEqual([
+      {
+        id: 'lb:org1:Demo_course:html:text',
+        blockType: 'html',
+        defKey: 'def_key',
+        displayName: 'text block',
+        lastPublished: null,
+        publishedBy: null,
+        lastDraftCreated: null,
+        lastDraftCreatedBy: null,
+        hasUnpublishedChanges: false,
+        created: null,
+        modified: null,
+        tagsCount: 0,
+        collections: ['col1', 'col2'],
+      },
+      {
+        id: 'lb:org1:Demo_course:video:video1',
+        blockType: 'video',
+        defKey: 'def_key',
+        displayName: 'video block',
+        lastPublished: null,
+        publishedBy: null,
+        lastDraftCreated: null,
+        lastDraftCreatedBy: null,
+        hasUnpublishedChanges: false,
+        created: null,
+        modified: null,
+        tagsCount: 0,
+        collections: ['col2'],
+      },
+    ]);
+    expect(axiosMock.history.get[0].url).toEqual(url);
+  });
 });