2 files changed, 112 insertions, 50 deletions
diff --git a/src/lib/Data/AniList/cacheHydration.ts b/src/lib/Data/AniList/cacheHydration.ts
new file mode 100644
index 00000000..434d2a82
--- /dev/null
+++ b/src/lib/Data/AniList/cacheHydration.ts
@@ -0,0 +1,48 @@
+import { browser } from "$app/environment";
+import anime from "$stores/anime";
+import lastPruneTimes from "$stores/lastPruneTimes";
+import manga from "$stores/manga";
+import localforage from "localforage";
+
+type MediaCacheKind = "anime" | "manga";
+
+interface StoredLastPruneTimes {
+	anime: number;
+	chapters: number;
+	manga: number;
+}
+
+const hydration = new Map<MediaCacheKind, Promise<void>>();
+
+const isStoredLastPruneTimes = (
+	value: unknown,
+): value is StoredLastPruneTimes =>
+	typeof value === "object" &&
+	value !== null &&
+	typeof (value as StoredLastPruneTimes).anime === "number" &&
+	typeof (value as StoredLastPruneTimes).chapters === "number" &&
+	typeof (value as StoredLastPruneTimes).manga === "number";
+
+export const hydrateMediaListCache = (kind: MediaCacheKind) => {
+	if (!browser) return Promise.resolve();
+
+	const existing = hydration.get(kind);
+
+	if (existing) return existing;
+
+	const promise = (async () => {
+		const [cache, pruneTimes] = await Promise.all([
+			localforage.getItem<string>(kind),
+			localforage.getItem<StoredLastPruneTimes>("lastPruneTimes"),
+		]);
+
+		if (typeof cache === "string" && cache.length)
+			(kind === "anime" ? anime : manga).set(cache);
+
+		if (isStoredLastPruneTimes(pruneTimes)) lastPruneTimes.set(pruneTimes);
+	})();
+
+	hydration.set(kind, promise);
+
+	return promise;
+};
diff --git a/src/lib/Data/AniList/media.ts b/src/lib/Data/AniList/media.ts
index f2a4aad6..d8315b19 100644
--- a/src/lib/Data/AniList/media.ts
+++ b/src/lib/Data/AniList/media.ts
@@ -233,6 +233,21 @@ const assignDefaultOptions = (options: CollectionOptions) => {
 	return nonNullOptions;
 };
 
+const inFlightCollections = new Map<string, Promise<Media[]>>();
+
+const collectionKey = (
+	type: Type,
+	userId: number,
+	options: CollectionOptions,
+) =>
+	JSON.stringify({
+		type,
+		userId,
+		includeCompleted: options.includeCompleted,
+		all: options.all,
+		includeRelations: options.includeRelations,
+	});
+
 export const mediaListCollection = async (
 	anilistAuthorisation: AniListAuthorisation,
 	userIdentity: UserIdentity,
@@ -274,61 +289,60 @@ export const mediaListCollection = async (
 	if (mediaCache !== undefined && mediaCache !== "")
 		return parseJsonStringOrDefault<Media[]>(mediaCache, []);
 
-	const userIdResponse = await (
-		await fetch("https://graphql.anilist.co", {
-			method: "POST",
-			headers: {
-				Authorization: `${anilistAuthorisation.tokenType} ${anilistAuthorisation.accessToken}`,
-				"Content-Type": "application/json",
-				Accept: "application/json",
-			},
-			body: JSON.stringify({
-				query: collectionQueryTemplate(type, userIdentity.id, options),
-			}),
-		})
-	).json();
+	const key = collectionKey(type, userIdentity.id, options);
+	const existing = inFlightCollections.get(key);
 
-	if (
-		!userIdResponse["data"] ||
-		!userIdResponse["data"]["MediaListCollection"] ||
-		!userIdResponse["data"]["MediaListCollection"]["lists"]
-	)
-		return [];
+	if (existing) return existing;
 
-	if (mediaCache === "")
-		if (type === Type.Anime)
-			anime.set(
-				JSON.stringify(
-					flattenLists(
-						userIdResponse["data"]["MediaListCollection"]["lists"],
-						options.all,
-					),
-				),
-			);
-		else
-			manga.set(
-				JSON.stringify(
-					flattenLists(
-						userIdResponse["data"]["MediaListCollection"]["lists"],
-						options.all,
-					),
-				),
-			);
+	const request = (async () => {
+		const userIdResponse = await (
+			await fetch("https://graphql.anilist.co", {
+				method: "POST",
+				headers: {
+					Authorization: `${anilistAuthorisation.tokenType} ${anilistAuthorisation.accessToken}`,
+					"Content-Type": "application/json",
+					Accept: "application/json",
+				},
+				body: JSON.stringify({
+					query: collectionQueryTemplate(type, userIdentity.id, options),
+				}),
+			})
+		).json();
 
-	if (options.addNotification)
-		options.addNotification(
-			getOptions({
-				heading: options.notificationType
-					? options.notificationType
-					: Type[type],
-				description: "Re-cached media lists from AniList",
-			}),
+		if (
+			!userIdResponse["data"] ||
+			!userIdResponse["data"]["MediaListCollection"] ||
+			!userIdResponse["data"]["MediaListCollection"]["lists"]
+		)
+			return [];
+
+		const flattened = flattenLists(
+			userIdResponse["data"]["MediaListCollection"]["lists"],
+			options.all,
 		);
 
-	return flattenLists(
-		userIdResponse["data"]["MediaListCollection"]["lists"],
-		options.all,
-	);
+		if (mediaCache === "")
+			if (type === Type.Anime) anime.set(JSON.stringify(flattened));
+			else manga.set(JSON.stringify(flattened));
+
+		if (options.addNotification)
+			options.addNotification(
+				getOptions({
+					heading: options.notificationType
+						? options.notificationType
+						: Type[type],
+					description: "Re-cached media lists from AniList",
+				}),
+			);
+
+		return flattened;
+	})().finally(() => {
+		inFlightCollections.delete(key);
+	});
+
+	inFlightCollections.set(key, request);
+
+	return request;
 };
 
 export const publicMediaListCollection = async (