Batch LibreTranslate furnidata translations via the array API

Translate deduplicated texts in batches of 48 with 4 parallel workers
instead of one request per string, serve cached hits locally, and
persist results so rebuilds never re-call the API for the same text.

src/lib/services/furni-data-i18n.ts

@@ -169,6 +169,114 @@ async function translateWithLibre(
 	}
 }
 
+const LIBRE_BATCH_SIZE = 48;
+const LIBRE_CONCURRENCY = 4;
+
+/**
+ * Translate many texts in one go using LibreTranslate's array API
+ * (q accepts string[] → translatedText: string[]). Deduplicates input,
+ * serves everything already in the cache, then fetches the rest in
+ * parallel batches. Returns a map of trimmed source text → translation.
+ * Texts whose batch failed are simply absent from the result.
+ */
+async function translateManyWithLibre(
+	texts: Iterable<string>,
+	targetLang: string,
+): Promise<Map<string, string>> {
+	const result = new Map<string, string>();
+	if (targetLang === "en") return result;
+
+	const cache = await loadLibreCache();
+	const pending = new Set<string>();
+	for (const raw of texts) {
+		const trimmed = raw.trim();
+		if (!trimmed) continue;
+		const key = `${targetLang}|${trimmed}`;
+		const cached = cache.get(key);
+		if (cached !== undefined) {
+			result.set(trimmed, cached);
+			continue;
+		}
+		pending.add(trimmed);
+	}
+	if (pending.size === 0) return result;
+
+	const chunks: string[][] = [];
+	let current: string[] = [];
+	for (const text of pending) {
+		current.push(text);
+		if (current.length >= LIBRE_BATCH_SIZE) {
+			chunks.push(current);
+			current = [];
+		}
+	}
+	if (current.length > 0) chunks.push(current);
+
+	const url = await getLibreTranslateUrl();
+	let failures = 0;
+	let nextChunk = 0;
+	const worker = async (): Promise<void> => {
+		while (true) {
+			const i = nextChunk++;
+			if (i >= chunks.length) return;
+			const chunk = chunks[i];
+			try {
+				const res = await fetch(`${url}/translate`, {
+					method: "POST",
+					headers: { "Content-Type": "application/json" },
+					body: JSON.stringify({
+						q: chunk,
+						source: "en",
+						target: targetLang,
+						format: "text",
+					}),
+					signal: AbortSignal.timeout(30_000),
+				});
+				if (!res.ok) {
+					failures++;
+					logger.warn(
+						`[furni-i18n] LibreTranslate batch ${targetLang} failed: ${res.status}`,
+					);
+					continue;
+				}
+				const data = (await res.json()) as {
+					translatedText?: string[] | string;
+				};
+				const out = Array.isArray(data.translatedText)
+					? data.translatedText
+					: typeof data.translatedText === "string"
+						? [data.translatedText]
+						: [];
+				for (let j = 0; j < chunk.length; j++) {
+					const translated =
+						typeof out[j] === "string" && out[j] ? out[j] : chunk[j];
+					result.set(chunk[j], translated);
+					cache.set(`${targetLang}|${chunk[j]}`, translated);
+				}
+			} catch (err) {
+				failures++;
+				logger.warn(`[furni-i18n] LibreTranslate batch error (${targetLang})`, {
+					error: (err as Error).message,
+				});
+			}
+		}
+	};
+	await Promise.all(
+		Array.from({ length: Math.min(LIBRE_CONCURRENCY, chunks.length) }, () =>
+			worker(),
+		),
+	);
+
+	if (failures > 0) {
+		logger.warn(
+			`[furni-i18n] LibreTranslate ${targetLang}: ${failures}/${chunks.length} batches failed`,
+		);
+	}
+	// Persist whatever succeeded so rebuilds don't re-call the API.
+	await saveLibreCache();
+	return result;
+}
+
 function lookupTranslation(
 	map: Map<string, Translation>,
 	classname: string,
@@ -189,6 +297,19 @@ function lookupTranslation(
 	return undefined;
 }
 
+/**
+ * A language mapped to hotel "com" only carries English names, so it must
+ * NOT be treated as a real translation — fall through to LibreTranslate for
+ * those (pl/ru/ar/ja). Shared by the full build and the single-import patch
+ * so both paths stay in sync.
+ */
+function officialIsRealTranslation(
+	lang: string,
+	hotel: HabboGamedataHotel,
+): boolean {
+	return lang === "en" || hotel !== "com";
+}
+
 async function fetchTranslationsForHotel(
 	hotel: HabboGamedataHotel,
 ): Promise<Map<string, Translation>> {
@@ -318,59 +439,65 @@ export async function buildLocalizedFurniDataFiles(): Promise<
 				const cloned = cloneFurniData(
 					master as unknown as Record<string, unknown>,
 				);
-				let translatedRoom = 0;
-				let translatedWall = 0;
+				const officialIsReal = officialIsRealTranslation(lang, hotel);
 
+				// Pass 1 — apply official translations directly and collect the
+				// texts that need LibreTranslate (customs, or languages whose
+				// hotel only provides English) so they can be batch-translated.
+				const pendingRefs: Array<{
+					entry: Record<string, unknown>;
+					field: "name" | "description";
+					section: "roomitemtypes" | "wallitemtypes";
+				}> = [];
+				const pendingTexts = new Set<string>();
 				for (const section of ["roomitemtypes", "wallitemtypes"] as const) {
 					const arr = cloned[section]?.furnitype;
 					if (!Array.isArray(arr)) continue;
-					// A language mapped to hotel "com" only carries English names,
-					// so it must NOT be treated as a real translation — fall through
-					// to LibreTranslate for those (pl/ru/ar/ja).
-					const officialIsReal = lang === "en" || hotel !== "com";
 					for (const entry of arr) {
 						const cn =
 							typeof entry.classname === "string" ? entry.classname : "";
 						if (!cn) continue;
 						const t = lookupTranslation(map, cn);
-						let didTranslate = false;
-						// Prefer the official Habbo translation when it carries content;
-						// otherwise fall back to LibreTranslate (customs, or languages
-						// whose hotel only provides English) so every entry gets a
-						// localized name/description rather than staying English.
 						if (officialIsReal && t?.name) {
 							entry.name = t.name;
-							didTranslate = true;
 						} else if (
 							lang !== "en" &&
 							typeof entry.name === "string" &&
 							entry.name.trim()
 						) {
-							const translated = await translateWithLibre(entry.name, lang);
-							if (translated && translated !== entry.name) {
-								entry.name = translated;
-								didTranslate = true;
-							}
+							pendingTexts.add(entry.name.trim());
+							pendingRefs.push({ entry, field: "name", section });
 						}
 						if (officialIsReal && t?.description) {
 							entry.description = t.description;
-							didTranslate = true;
 						} else if (
 							lang !== "en" &&
 							typeof entry.description === "string" &&
 							entry.description.trim()
 						) {
-							const translated = await translateWithLibre(
-								entry.description,
-								lang,
-							);
-							if (translated && translated !== entry.description) {
-								entry.description = translated;
-								didTranslate = true;
-							}
+							pendingTexts.add(entry.description.trim());
+							pendingRefs.push({ entry, field: "description", section });
 						}
-						if (didTranslate) {
-							if (section === "roomitemtypes") translatedRoom++;
+					}
+				}
+
+				// Pass 2 — batch-translate everything pending in a handful of
+				// parallel requests instead of one HTTP call per text.
+				const translations = await translateManyWithLibre(pendingTexts, lang);
+
+				let translatedRoom = 0;
+				let translatedWall = 0;
+				if (pendingRefs.length > 0) {
+					const counted = new Set<Record<string, unknown>>();
+					for (const ref of pendingRefs) {
+						const original = ref.entry[ref.field];
+						if (typeof original !== "string") continue;
+						const translated = translations.get(original.trim());
+						if (translated === undefined || translated === original) continue;
+						ref.entry[ref.field] = translated;
+						if (!counted.has(ref.entry)) {
+							counted.add(ref.entry);
+							if (ref.section === "roomitemtypes") translatedRoom++;
 							else translatedWall++;
 						}
 					}
@@ -445,6 +572,7 @@ export async function patchLocalizedFurniDataEntries(
 
 		for (const { lang, hotel, map } of maps) {
 			try {
+				const officialIsReal = officialIsRealTranslation(lang, hotel);
 				const targets = await getLocalizedWritePaths(lang);
 				// Load the existing language file if present, otherwise clone master.
 				let data: Record<string, { furnitype: Array<Record<string, unknown>> }>;
@@ -465,6 +593,10 @@ export async function patchLocalizedFurniDataEntries(
 							const cn =
 								typeof entry.classname === "string" ? entry.classname : "";
 							if (!cn) continue;
+							// Only real official translations count here — English names
+							// from a com-mapped hotel must not be written over the file
+							// as if they were localized.
+							if (!officialIsReal) continue;
 							const t = lookupTranslation(map, cn);
 							if (t?.name) entry.name = t.name;
 							if (t?.description) entry.description = t.description;
@@ -487,7 +619,7 @@ export async function patchLocalizedFurniDataEntries(
 						const origDesc =
 							wantedEntry.description ??
 							(typeof entry.description === "string" ? entry.description : "");
-						if (t?.name) {
+						if (officialIsReal && t?.name) {
 							entry.name = t.name;
 							didPatch = true;
 						} else if (lang !== "en" && origName) {
@@ -497,7 +629,7 @@ export async function patchLocalizedFurniDataEntries(
 								didPatch = true;
 							}
 						}
-						if (t?.description) {
+						if (officialIsReal && t?.description) {
 							entry.description = t.description;
 							didPatch = true;
 						} else if (lang !== "en" && origDesc) {
@@ -546,13 +678,17 @@ export async function patchLocalizedFurniDataEntries(
 					if (!found || !foundSection) continue;
 					const clone = { ...found };
 					const t = lookupTranslation(map, classname);
-					if (t?.name) clone.name = t.name;
+					if (officialIsReal && t?.name) clone.name = t.name;
 					else if (lang !== "en") {
 						const src =
 							name ?? (typeof found.name === "string" ? found.name : "") ?? "";
-						if (src) clone.name = await translateWithLibre(src, lang);
+						if (src) {
+							const translated = await translateWithLibre(src, lang);
+							if (translated !== src) clone.name = translated;
+						}
 					}
-					if (t?.description) clone.description = t.description;
+					if (officialIsReal && t?.description)
+						clone.description = t.description;
 					else if (lang !== "en") {
 						const src =
 							description ??
@@ -560,7 +696,10 @@ export async function patchLocalizedFurniDataEntries(
 								? found.description
 								: "") ??
 							"";
-						if (src) clone.description = await translateWithLibre(src, lang);
+						if (src) {
+							const translated = await translateWithLibre(src, lang);
+							if (translated !== src) clone.description = translated;
+						}
 					}
 					if (!data[foundSection]) data[foundSection] = { furnitype: [] };
 					data[foundSection].furnitype.push(clone);