From 0a9ce84cf21695ea17bab71d3b005965b0416f5b Mon Sep 17 00:00:00 2001
From: Elian Doran <contact@eliandoran.me>
Date: Mon, 29 Dec 2025 19:10:14 +0200
Subject: [PATCH] feat(client/pdf): respect locale

---
 .../src/widgets/type_widgets/file/Pdf.tsx       |  9 ++++++---
 packages/pdfjs-viewer/src/custom.ts             | 17 ++++++++++++++---
 .../src/{history.ts => persistence.ts}          |  6 +++++-
 3 files changed, 25 insertions(+), 7 deletions(-)
 rename packages/pdfjs-viewer/src/{history.ts => persistence.ts} (88%)

diff --git a/apps/client/src/widgets/type_widgets/file/Pdf.tsx b/apps/client/src/widgets/type_widgets/file/Pdf.tsx
index 5d2767bb9..fcce704cf 100644
--- a/apps/client/src/widgets/type_widgets/file/Pdf.tsx
+++ b/apps/client/src/widgets/type_widgets/file/Pdf.tsx
@@ -5,6 +5,7 @@ import FBlob from "../../../entities/fblob";
 import FNote from "../../../entities/fnote";
 import server from "../../../services/server";
 import { useViewModeConfig } from "../../collections/NoteList";
+import { useTriliumOption } from "../../react/hooks";
 
 const VARIABLE_WHITELIST = new Set([
     "root-background",
@@ -21,6 +22,7 @@ export default function PdfPreview({ note, blob, componentId }: {
     const iframeRef = useRef<HTMLIFrameElement>(null);
     const { onLoad } = useStyleInjection(iframeRef);
     const historyConfig = useViewModeConfig(note, "pdfHistory");
+    const [ locale ] = useTriliumOption("locale");
 
     useEffect(() => {
         function handleMessage(event: MessageEvent) {
@@ -51,10 +53,11 @@ export default function PdfPreview({ note, blob, componentId }: {
         <iframe
             ref={iframeRef}
             class="pdf-preview"
-            src={`pdfjs/web/viewer.html?file=../../api/notes/${note.noteId}/open`}
+            src={`pdfjs/web/viewer.html?file=../../api/notes/${note.noteId}/open&lang=${locale}`}
             onLoad={() => {
-                if (iframeRef.current?.contentWindow) {
-                    iframeRef.current.contentWindow.TRILIUM_VIEW_HISTORY_STORE = historyConfig.config;
+                const win = iframeRef.current?.contentWindow;
+                if (win) {
+                    win.TRILIUM_VIEW_HISTORY_STORE = historyConfig.config;
                 }
                 onLoad();
             }}
diff --git a/packages/pdfjs-viewer/src/custom.ts b/packages/pdfjs-viewer/src/custom.ts
index 22caff2b6..aab78afc9 100644
--- a/packages/pdfjs-viewer/src/custom.ts
+++ b/packages/pdfjs-viewer/src/custom.ts
@@ -1,15 +1,15 @@
-import interceptViewHistory from "./history";
+import interceptPersistence from "./persistence";
 
 const LOG_EVENT_BUS = false;
 
 async function main() {
+    interceptPersistence(getCustomAppOptions());
+
     // Wait for the PDF viewer application to be available.
     while (!window.PDFViewerApplication) {
         await new Promise(r => setTimeout(r, 50));
     }
-
     const app = window.PDFViewerApplication;
-    interceptViewHistory();
 
     if (LOG_EVENT_BUS) {
         patchEventBus();
@@ -20,6 +20,17 @@ async function main() {
     await app.initializedPromise;
 };
 
+function getCustomAppOptions() {
+    const urlParams = new URLSearchParams(window.location.search);
+
+    return {
+        localeProperties: {
+            // Read from URL query
+            lang: urlParams.get("lang") || "en"
+        }
+    };
+}
+
 function manageSave() {
     const app = window.PDFViewerApplication;
     const storage = app.pdfDocument.annotationStorage;
diff --git a/packages/pdfjs-viewer/src/history.ts b/packages/pdfjs-viewer/src/persistence.ts
similarity index 88%
rename from packages/pdfjs-viewer/src/history.ts
rename to packages/pdfjs-viewer/src/persistence.ts
index 21c2966d4..965b5a54b 100644
--- a/packages/pdfjs-viewer/src/history.ts
+++ b/packages/pdfjs-viewer/src/persistence.ts
@@ -1,4 +1,4 @@
-export default function interceptViewHistory() {
+export default function interceptViewHistory(customOptions?: object) {
     const originalSetItem = Storage.prototype.setItem;
     Storage.prototype.setItem = function (key: string, value: string) {
         if (key === "pdfjs.history") {
@@ -11,6 +11,10 @@ export default function interceptViewHistory() {
 
     const originalGetItem = Storage.prototype.getItem;
     Storage.prototype.getItem = function (key: string) {
+        if (key === "pdfjs.preferences") {
+            return JSON.stringify(customOptions);
+        }
+
         if (key === "pdfjs.history") {
             return JSON.stringify(window.TRILIUM_VIEW_HISTORY_STORE || {});
         }