From 15b17a74ff60eb3d682aa86ca9700207f0cc2180 Mon Sep 17 00:00:00 2001
From: Woody <woody.ck.tse@gmail.com>
Date: Sat, 25 Apr 2026 17:56:06 +0800
Subject: [PATCH] =?UTF-8?q?fix(frontend):=20chunk=20PDFs=20are=20single-pa?=
 =?UTF-8?q?ge=20=E2=80=94=20always=20render=20page=201?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Chunk PDFs like 'NEC4 ACC_page_5.pdf' contain only 1 page (the extracted
page). Passing the original page number (e.g. 5) to <Page> caused
'Invalid page request' because the file only has 1 page.

- Always render pageNumber={1} for <Page> component
- Display originalPage in UI title to show source page number
- Disable prev/next navigation since chunk PDFs are single-page
---
 frontend/src/pages/PdfViewerPage.tsx | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/frontend/src/pages/PdfViewerPage.tsx b/frontend/src/pages/PdfViewerPage.tsx
index 6b9b6ea..fe83ead 100644
--- a/frontend/src/pages/PdfViewerPage.tsx
+++ b/frontend/src/pages/PdfViewerPage.tsx
@@ -13,11 +13,11 @@ const DEFAULT_ZOOM_INDEX = 2
 export const PdfViewerPage: React.FC = () => {
   const [searchParams] = useSearchParams()
   const pdfUrl = searchParams.get('url') ?? ''
-  const initialPage = parseInt(searchParams.get('page') ?? '1', 10)
+  const originalPage = parseInt(searchParams.get('page') ?? '1', 10)
   const title = searchParams.get('title') ?? 'PDF Viewer'
 
   const [numPages, setNumPages] = useState<number>(0)
-  const [pageNumber, setPageNumber] = useState<number>(initialPage)
+  const [pageNumber] = useState<number>(1)
   const [zoomIndex, setZoomIndex] = useState<number>(DEFAULT_ZOOM_INDEX)
   const [loadError, setLoadError] = useState<string | null>(null)
   const [pageError, setPageError] = useState<string | null>(null)
@@ -36,8 +36,6 @@ export const PdfViewerPage: React.FC = () => {
     setPageError(error.message)
   }, [])
 
-  const goToPrevPage = () => setPageNumber((prev) => Math.max(1, prev - 1))
-  const goToNextPage = () => setPageNumber((prev) => Math.min(numPages, prev + 1))
   const zoomIn = () => setZoomIndex((prev) => Math.min(ZOOM_LEVELS.length - 1, prev + 1))
   const zoomOut = () => setZoomIndex((prev) => Math.max(0, prev - 1))
 
@@ -61,19 +59,17 @@ export const PdfViewerPage: React.FC = () => {
         </Link>
         <div className="flex items-center space-x-2">
           <button
-            onClick={goToPrevPage}
-            disabled={pageNumber <= 1}
-            className="p-1 rounded hover:bg-gray-100 disabled:opacity-30 disabled:cursor-not-allowed"
+            disabled
+            className="p-1 rounded disabled:opacity-30 disabled:cursor-not-allowed"
           >
             <ChevronLeft className="w-4 h-4" />
           </button>
           <span className="text-sm text-gray-700 min-w-[120px] text-center">
-            {title} — Page {pageNumber}{numPages > 0 ? ` of ${numPages}` : ''}
+            {title} — Page {originalPage}
           </span>
           <button
-            onClick={goToNextPage}
-            disabled={pageNumber >= numPages}
-            className="p-1 rounded hover:bg-gray-100 disabled:opacity-30 disabled:cursor-not-allowed"
+            disabled
+            className="p-1 rounded disabled:opacity-30 disabled:cursor-not-allowed"
           >
             <ChevronRight className="w-4 h-4" />
           </button>