improvement(files): fit-width previews and chip-chrome viewer controls (#5002)

* improvement(files): fit-width previews and chip-chrome viewer controls

- PDF and DOCX previews now treat 100% zoom as fit-to-width instead of
  capping at the page's natural print size, removing the dead gutters in
  wide panels (pdf.js re-renders the canvas at the target width and DOCX
  uses CSS zoom, so both stay crisp)
- PreviewToolbar page/zoom controls move from 24px ghost Buttons with
  off-token labels to canonical emcn chips (icon-only Chip pills, text-sm
  --text-body value labels)
- XLSX sheet tabs move from underline-style ghost Buttons to a chip
  cluster using the active pill state
- Audio preview swaps the music emoji for the lucide Music icon on
  design-system tokens

* improvement(files): debounce PDF panel-resize re-rasterisation

With fit-to-width every pageWidth change re-rasterises all page canvases,
so per-tick updates during a panel-divider drag re-rendered the document
continuously. First measurement still applies immediately.

* fix(files): don't let a zero-width first measurement consume the immediate resize slot

A hidden container reports zero width from the ResizeObserver; treating
that as the initial measurement pushed the real first width onto the
debounce path and delayed initial render.

* improvement(files): module cleanup — dedupe media previews, debounce docx refits

- Merge the near-identical AudioPreview/VideoPreview into one MediaPreview
  (shared fetch/blob-URL/error/loading path; only the player differs)
- Debounce docx resize refits the same way the PDF preview debounces width
  measurements (the initial fit comes from the render path, not the observer)
- Document the load-bearing buffer copy in pdf-viewer (pdf.js transfers and
  detaches the ArrayBuffer it receives)

apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/docx-preview.tsx

@@ -16,11 +16,14 @@ const DOCX_ZOOM_MIN = 25
 const DOCX_ZOOM_MAX = 400
 const DOCX_ZOOM_STEP = 20
 const DOCX_ZOOM_WHEEL_SENSITIVITY = 0.005
+const DOCX_RESIZE_DEBOUNCE_MS = 150
 
 /**
  * Fit the rendered docx pages to the host container width using a CSS scale.
  * The library renders `<section class="docx">` at the document's natural page
- * width (in cm), which overflows narrow panels.
+ * width (in cm), which overflows narrow panels. 100% zoom means fit-to-width —
+ * pages upscale past their natural print size in wide panels (CSS zoom of HTML
+ * stays crisp), matching the PDF preview's semantics.
  */
 function fitDocxToContainer(host: HTMLElement, viewport: HTMLElement, zoomPercent: number) {
   const wrapper = host.querySelector<HTMLElement>('.docx-wrapper')
@@ -48,7 +51,7 @@ function fitDocxToContainer(host: HTMLElement, viewport: HTMLElement, zoomPercen
     Number.parseFloat(wrapperStyle.paddingLeft) + Number.parseFloat(wrapperStyle.paddingRight)
   const naturalWrapperWidth = naturalPageWidth + horizontalPadding
   const available = viewport.clientWidth
-  const fitScale = Math.min(1, available / naturalWrapperWidth)
+  const fitScale = available / naturalWrapperWidth
   const scale = fitScale * (zoomPercent / 100)
   const scaledWrapperWidth = naturalWrapperWidth * scale
 
@@ -95,12 +98,25 @@ export const DocxPreview = memo(function DocxPreview({
     fitDocxToContainer(container, scrollContainer, zoomPercentRef.current)
   }, [])
 
+  /**
+   * Resize refits are debounced: each one re-queries the rendered pages and
+   * recomputes the fit scale, so per-tick refits during a panel-divider drag
+   * would thrash layout continuously (the initial fit is applied directly by
+   * the render path, not this observer). Mirrors the PDF preview's debounce.
+   */
   useEffect(() => {
     const scrollContainer = scrollContainerRef.current
     if (!scrollContainer) return
-    const observer = new ResizeObserver(() => applyPostRenderStyling())
+    let debounce: ReturnType<typeof setTimeout> | undefined
+    const observer = new ResizeObserver(() => {
+      clearTimeout(debounce)
+      debounce = setTimeout(() => applyPostRenderStyling(), DOCX_RESIZE_DEBOUNCE_MS)
+    })
     observer.observe(scrollContainer)
-    return () => observer.disconnect()
+    return () => {
+      clearTimeout(debounce)
+      observer.disconnect()
+    }
   }, [applyPostRenderStyling])
 
   const applyZoomAt = useCallback(

apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/file-viewer.tsx

@@ -2,6 +2,7 @@
 
 import { memo, useCallback, useEffect, useMemo, useRef, useState } from 'react'
 import { createLogger } from '@sim/logger'
+import { Music } from 'lucide-react'
 import dynamic from 'next/dynamic'
 import type { WorkspaceFileRecord } from '@/lib/uploads/contexts/workspace'
 import { getFileExtension } from '@/lib/uploads/utils/file-utils'
@@ -102,11 +103,11 @@ export function FileViewer({
   }
 
   if (category === 'audio-previewable') {
-    return <AudioPreview key={file.id} file={file} workspaceId={workspaceId} />
+    return <MediaPreview key={file.id} file={file} workspaceId={workspaceId} kind='audio' />
   }
 
   if (category === 'video-previewable') {
-    return <VideoPreview key={file.id} file={file} workspaceId={workspaceId} />
+    return <MediaPreview key={file.id} file={file} workspaceId={workspaceId} kind='video' />
   }
 
   if (category === 'docx-previewable') {
@@ -176,12 +177,21 @@ function useBlobUrl(workspaceId: string, fileId: string, fileKey: string) {
   return { fileData, isLoading, error, blobUrl, replaceBlobUrl }
 }
 
-const AudioPreview = memo(function AudioPreview({
+const MEDIA_FALLBACK_MIME = { audio: 'audio/mpeg', video: 'video/mp4' } as const
+
+/**
+ * Shared blob-backed preview for audio and video files — the fetch, blob-URL
+ * lifecycle, and error/loading handling are identical; only the rendered
+ * player differs.
+ */
+const MediaPreview = memo(function MediaPreview({
   file,
   workspaceId,
+  kind,
 }: {
   file: WorkspaceFileRecord
   workspaceId: string
+  kind: 'audio' | 'video'
 }) {
   const {
     fileData,
@@ -193,55 +203,31 @@ const AudioPreview = memo(function AudioPreview({
 
   useEffect(() => {
     if (!fileData) return
-    replaceBlobUrl(URL.createObjectURL(new Blob([fileData], { type: file.type || 'audio/mpeg' })))
-  }, [file.type, fileData, replaceBlobUrl])
+    replaceBlobUrl(
+      URL.createObjectURL(new Blob([fileData], { type: file.type || MEDIA_FALLBACK_MIME[kind] }))
+    )
+  }, [file.type, fileData, kind, replaceBlobUrl])
 
   const error = blobUrl !== null ? null : resolvePreviewError(fetchError, null)
-  if (error) return <PreviewError label='audio' error={error} />
+  if (error) return <PreviewError label={kind} error={error} />
 
   if (isLoading && !blobUrl) {
     return <PreviewLoadingFrame className='h-full' tone='surface' />
   }
 
-  return (
-    <div className='flex h-full flex-col items-center justify-center gap-4 bg-[var(--surface-1)] p-8'>
-      <div className='flex flex-col items-center gap-2 text-center'>
-        <div className='text-[32px]'>🎵</div>
-        <p className='font-medium text-[14px] text-[var(--text-primary)]'>{file.name}</p>
+  if (kind === 'audio') {
+    return (
+      <div className='flex h-full flex-col items-center justify-center gap-4 bg-[var(--surface-1)] p-8'>
+        <div className='flex flex-col items-center gap-2 text-center'>
+          <Music className='size-[32px] text-[var(--text-muted)]' strokeWidth={1.5} />
+          <p className='font-medium text-[14px] text-[var(--text-primary)]'>{file.name}</p>
+        </div>
+        {blobUrl && (
+          // biome-ignore lint/a11y/useMediaCaption: audio from workspace files
+          <audio src={blobUrl} controls className='w-full max-w-[480px]' />
+        )}
       </div>
-      {blobUrl && (
-        // biome-ignore lint/a11y/useMediaCaption: audio from workspace files
-        <audio src={blobUrl} controls className='w-full max-w-[480px]' />
-      )}
-    </div>
-  )
-})
-
-const VideoPreview = memo(function VideoPreview({
-  file,
-  workspaceId,
-}: {
-  file: WorkspaceFileRecord
-  workspaceId: string
-}) {
-  const {
-    fileData,
-    isLoading,
-    error: fetchError,
-    blobUrl,
-    replaceBlobUrl,
-  } = useBlobUrl(workspaceId, file.id, file.key)
-
-  useEffect(() => {
-    if (!fileData) return
-    replaceBlobUrl(URL.createObjectURL(new Blob([fileData], { type: file.type || 'video/mp4' })))
-  }, [file.type, fileData, replaceBlobUrl])
-
-  const error = blobUrl !== null ? null : resolvePreviewError(fetchError, null)
-  if (error) return <PreviewError label='video' error={error} />
-
-  if (isLoading && !blobUrl) {
-    return <PreviewLoadingFrame className='h-full' tone='surface' />
+    )
   }
 
   return (

apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/pdf-viewer.tsx

@@ -28,8 +28,8 @@ const PDF_ZOOM_MIN = 0.5
 const PDF_ZOOM_MAX = 3
 const PDF_ZOOM_DEFAULT = 1
 const PDF_ZOOM_STEP = 1.25
-const PDF_PAGE_MAX_WIDTH = 816
 const PDF_VIEWER_PADDING = 24
+const PDF_RESIZE_DEBOUNCE_MS = 150
 
 export type PdfDocumentSource =
   | { kind: 'url'; url: string }
@@ -66,25 +66,53 @@ export const PdfViewerCore = memo(function PdfViewerCore({ source, filename }: P
   const [loadError, setLoadError] = useState<string | null>(null)
 
   const sourceValue = source.kind === 'url' ? source.url : source.buffer
+  /**
+   * The buffer copy (`slice(0)`) is load-bearing: pdf.js transfers — and
+   * detaches — the ArrayBuffer it receives to its worker, so handing over the
+   * caller's buffer would leave it unusable on the next render or remount.
+   */
   const file = useMemo(
     () => (source.kind === 'url' ? source.url : { data: new Uint8Array(source.buffer.slice(0)) }),
     [sourceValue]
   )
 
+  /**
+   * The first non-zero measurement applies immediately so the document renders
+   * without delay (a hidden container reports zero width and must not consume
+   * the immediate slot); subsequent ones (panel-divider drags) are debounced
+   * because every pageWidth change makes pdf.js re-rasterise all page canvases
+   * — per-tick updates during a drag would re-render the whole document
+   * continuously.
+   */
   useEffect(() => {
     const container = containerRef.current
     if (!container) return
+    let hasMeasured = false
+    let debounce: ReturnType<typeof setTimeout> | undefined
     const observer = new ResizeObserver(([entry]) => {
-      setContainerWidth(entry.contentRect.width)
+      const { width } = entry.contentRect
+      if (!hasMeasured) {
+        if (width <= 0) return
+        hasMeasured = true
+        setContainerWidth(width)
+        return
+      }
+      clearTimeout(debounce)
+      debounce = setTimeout(() => setContainerWidth(width), PDF_RESIZE_DEBOUNCE_MS)
     })
     observer.observe(container)
-    return () => observer.disconnect()
+    return () => {
+      clearTimeout(debounce)
+      observer.disconnect()
+    }
   }, [])
 
-  const pageWidth =
-    containerWidth > 0
-      ? Math.min(containerWidth - 2 * PDF_VIEWER_PADDING, PDF_PAGE_MAX_WIDTH)
-      : undefined
+  /**
+   * 100% zoom fits the page to the panel width (pdf.js re-renders the canvas
+   * at the target width, so upscaling past the page's natural print size
+   * stays crisp). Matches the DOCX preview's fit-to-width semantics.
+   */
+  const pageWidth = containerWidth > 0 ? containerWidth - 2 * PDF_VIEWER_PADDING : undefined
   pageWidthRef.current = pageWidth
 
   const applyZoomAt = useCallback((next: number, anchorX: number, anchorY: number) => {

apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/preview-toolbar.tsx

@@ -1,5 +1,5 @@
 import { ChevronLeft, ChevronRight, ZoomIn, ZoomOut } from 'lucide-react'
-import { Button } from '@/components/emcn'
+import { Chip } from '@/components/emcn'
 import { cn } from '@/lib/core/utils/cn'
 
 interface PreviewNavigationControls {
@@ -31,14 +31,14 @@ export function PreviewToolbar({ navigation, zoom, className }: PreviewToolbarPr
   return (
     <div
       className={cn(
-        'flex shrink-0 items-center justify-between border-[var(--border)] border-b bg-[var(--surface-1)] px-3 py-1.5',
+        'flex shrink-0 items-center justify-between border-[var(--border)] border-b bg-[var(--surface-1)] px-2 py-1',
         className
       )}
     >
-      <div className='flex items-center gap-1'>
+      <div className='flex items-center'>
         {navigation && <PreviewNavigationControls {...navigation} />}
       </div>
-      <div className='flex items-center gap-1'>{zoom && <PreviewZoomControls {...zoom} />}</div>
+      <div className='flex items-center'>{zoom && <PreviewZoomControls {...zoom} />}</div>
     </div>
   )
 }
@@ -54,29 +54,21 @@ function PreviewNavigationControls({
 }: PreviewNavigationControls) {
   return (
     <>
-      <Button
-        variant='ghost'
-        size='sm'
+      <Chip
+        leftIcon={ChevronLeft}
         onClick={onPrevious}
         disabled={!canPrevious}
-        className='size-6 p-0 text-[var(--text-icon)]'
         aria-label={`Previous ${label}`}
-      >
-        <ChevronLeft className='size-[14px]' />
-      </Button>
-      <span className='min-w-[5rem] text-center text-[12px] text-[var(--text-secondary)]'>
+      />
+      <span className='min-w-[4.5rem] text-center text-[var(--text-body)] text-sm'>
         {total > 0 ? `${current} / ${total}` : '0 / 0'}
       </span>
-      <Button
-        variant='ghost'
-        size='sm'
+      <Chip
+        leftIcon={ChevronRight}
         onClick={onNext}
         disabled={!canNext}
-        className='size-6 p-0 text-[var(--text-icon)]'
         aria-label={`Next ${label}`}
-      >
-        <ChevronRight className='size-[14px]' />
-      </Button>
+      />
     </>
   )
 }
@@ -92,39 +84,13 @@ function PreviewZoomControls({
   return (
     <>
       {onReset && (
-        <Button
-          variant='ghost'
-          size='sm'
-          onClick={onReset}
-          className='h-6 px-2 text-[11px]'
-          aria-label='Reset zoom'
-        >
+        <Chip onClick={onReset} aria-label='Reset zoom'>
           Reset
-        </Button>
+        </Chip>
       )}
-      <Button
-        variant='ghost'
-        size='sm'
-        onClick={onZoomOut}
-        disabled={!canZoomOut}
-        className='size-6 p-0 text-[var(--text-icon)]'
-        aria-label='Zoom out'
-      >
-        <ZoomOut className='size-[14px]' />
-      </Button>
-      <span className='min-w-[3rem] text-center text-[12px] text-[var(--text-secondary)]'>
-        {label}
-      </span>
-      <Button
-        variant='ghost'
-        size='sm'
-        onClick={onZoomIn}
-        disabled={!canZoomIn}
-        className='size-6 p-0 text-[var(--text-icon)]'
-        aria-label='Zoom in'
-      >
-        <ZoomIn className='size-[14px]' />
-      </Button>
+      <Chip leftIcon={ZoomOut} onClick={onZoomOut} disabled={!canZoomOut} aria-label='Zoom out' />
+      <span className='min-w-[3.25rem] text-center text-[var(--text-body)] text-sm'>{label}</span>
+      <Chip leftIcon={ZoomIn} onClick={onZoomIn} disabled={!canZoomIn} aria-label='Zoom in' />
     </>
   )
 }

apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/xlsx-preview.tsx

@@ -4,8 +4,7 @@ import { memo, useEffect, useRef, useState } from 'react'
 import { createLogger } from '@sim/logger'
 import { toError } from '@sim/utils/errors'
 import type { WorkBook } from 'xlsx'
-import { Button } from '@/components/emcn'
-import { cn } from '@/lib/core/utils/cn'
+import { Chip } from '@/components/emcn'
 import type { WorkspaceFileRecord } from '@/lib/uploads/contexts/workspace'
 import { DataTable } from './data-table'
 import { PreviewError, PreviewLoadingFrame, resolvePreviewError } from './preview-shared'
@@ -115,23 +114,17 @@ export const XlsxPreview = memo(function XlsxPreview({
 
   return (
     <div className='flex flex-1 flex-col overflow-hidden'>
-      <div className='flex shrink-0 items-center justify-between border-[var(--border)] border-b bg-[var(--surface-1)]'>
-        <div className='flex gap-0'>
+      <div className='flex shrink-0 items-center border-[var(--border)] border-b bg-[var(--surface-1)] px-2 py-1'>
+        <div className='flex items-center overflow-x-auto'>
           {sheetNames.map((name, i) => (
-            <Button
+            <Chip
               key={name}
-              variant='ghost'
-              size='sm'
+              active={i === activeSheet}
               onClick={() => setActiveSheet(i)}
-              className={cn(
-                'rounded-none px-3 py-1.5 text-[12px]',
-                i === activeSheet
-                  ? 'border-[var(--brand-secondary)] border-b-2 font-medium text-[var(--text-primary)]'
-                  : 'text-[var(--text-muted)] hover:text-[var(--text-secondary)]'
-              )}
+              className='shrink-0'
             >
               {name}
-            </Button>
+            </Chip>
           ))}
         </div>
       </div>