1 files changed, 98 insertions, 0 deletions
diff --git a/src/context/today-card-layout.ts b/src/context/today-card-layout.ts
new file mode 100644
index 0000000..54f66ec
--- /dev/null
+++ b/src/context/today-card-layout.ts
@@ -0,0 +1,98 @@
+import { getContext, setContext } from 'svelte';
+
+import type { TodayPage } from '@jet-app/app-store/api/models';
+import {
+    type TodayCardShelf,
+    isTodayCardShelf,
+} from '~/components/jet/shelf/TodayCardShelf.svelte';
+
+/**
+ * Describes the configuration of the card layout within a {@linkcode TodayCardShelf}
+ */
+interface LayoutConfiguration {
+    wrap: {
+        shouldStretchFirstCard: boolean;
+    };
+    nowrap: {
+        shouldStretchFirstCard: boolean;
+    };
+}
+
+const LAYOUT_CONFIGURATION_FALLBACK: LayoutConfiguration = Object.freeze({
+    wrap: {
+        shouldStretchFirstCard: true,
+    },
+    nowrap: {
+        shouldStretchFirstCard: true,
+    },
+});
+
+type TodayCardLayoutStore = WeakMap<TodayCardShelf, LayoutConfiguration>;
+type TodayCardLayoutStoreContext = TodayCardLayoutStore | undefined;
+
+const TODAY_CARD_LAYOUT_CONTEXT_ID = 'today-card-layout-context';
+
+/**
+ * Store the {@linkcode LayoutConfiguration} for each {@linkcode TodayCardShelf} in a
+ * {@linkcode TodayPage} in "context", so it can be retrieved at the shelf-component level
+ *
+ * This is necessary because the layout of the cards within each shelf of a {@linkcode TodayPage}
+ * is only knowable given information about the shelves that were rendered before it
+ *
+ * The information about the shelf layout is persisted through the "context" API so that the
+ * rendering of a {@linkcode TodayPage} can defer to the "default" page component, which requires
+ * that we pass no additional arguments into each shelf component
+ *
+ * {@linkcode getTodayCardLayoutConfiguration} can be used to look up the {@linkcode LayoutConfiguration}
+ * stored for a given {@linkcode TodayCardShelf}
+ */
+export function setTodayCardLayoutContext(page: Pick<TodayPage, 'shelves'>) {
+    const store: TodayCardLayoutStore = new WeakMap();
+
+    let shouldStretchFirstCardMultiline = false;
+    let shouldStretchFirstCardInline = false;
+
+    for (const shelf of page.shelves) {
+        // Skip any non-`TodayCard` shelves
+        if (!isTodayCardShelf(shelf)) {
+            continue;
+        }
+
+        store.set(shelf, {
+            wrap: {
+                shouldStretchFirstCard: shouldStretchFirstCardMultiline,
+            },
+            nowrap: {
+                shouldStretchFirstCard: shouldStretchFirstCardInline,
+            },
+        });
+
+        // In the multi-line card configuration, shelves with two or three cards in them will
+        // require that the next shelf swaps to stretching the cards at the opposite end
+        if (shelf.items.length === 2 || shelf.items.length === 3) {
+            shouldStretchFirstCardMultiline = !shouldStretchFirstCardMultiline;
+        }
+
+        // In the "inline" card configuration, each shelf should always alternate which end the
+        // card is stretched on
+        shouldStretchFirstCardInline = !shouldStretchFirstCardInline;
+    }
+
+    setContext<TodayCardLayoutStoreContext>(
+        TODAY_CARD_LAYOUT_CONTEXT_ID,
+        store,
+    );
+}
+
+/**
+ * Retrieve the {@linkcode LayoutConfiguration} for a given {@linkcode TodayCardShelf}
+ */
+export function getTodayCardLayoutConfiguration(
+    shelf: TodayCardShelf,
+): LayoutConfiguration {
+    const todayCardLayout = getContext<TodayCardLayoutStoreContext>(
+        TODAY_CARD_LAYOUT_CONTEXT_ID,
+    );
+
+    return todayCardLayout?.get(shelf) ?? LAYOUT_CONFIGURATION_FALLBACK;
+}