feat: add error, empty, and oversize states to html viewer

apps/x/apps/renderer/src/App.tsx

@@ -1425,10 +1425,11 @@ function App() {
     }
     const requestId = (fileLoadRequestIdRef.current += 1)
     const pathToLoad = selectedPath
-    // For HTML files, clear stale content immediately so the viewer shows
+    // HtmlFileViewer self-loads (with size check, error states, etc.)
-    // its loading state instead of rendering the previous file's bytes.
+    // Skip the generic loader so we don't double-fetch large files.
     if (pathToLoad.toLowerCase().endsWith('.html') || pathToLoad.toLowerCase().endsWith('.htm')) {
       setFileContent('')
+      return
     }
     let cancelled = false
     ;(async () => {
@@ -4827,7 +4828,7 @@ function App() {
                   </div>
                 ) : selectedPath?.toLowerCase().endsWith('.html') || selectedPath?.toLowerCase().endsWith('.htm') ? (
                   <div className="flex-1 min-h-0 overflow-hidden">
-                    <HtmlFileViewer html={fileContent} path={selectedPath} />
+                    <HtmlFileViewer path={selectedPath} />
                   </div>
                 ) : (
                   <div className="flex-1 overflow-auto p-4">

apps/x/apps/renderer/src/components/html-file-viewer.tsx

@@ -1,33 +1,114 @@
 import { useEffect, useState } from 'react'
-import { Loader2Icon } from 'lucide-react'
+import { AlertCircleIcon, ExternalLinkIcon, FileTextIcon, Loader2Icon } from 'lucide-react'
+
+const MAX_SIZE_BYTES = 5 * 1024 * 1024
+
+type ViewerState =
+  | { kind: 'loading' }
+  | { kind: 'loaded'; html: string }
+  | { kind: 'empty' }
+  | { kind: 'tooLarge'; sizeMB: number }
+  | { kind: 'error'; message: string }
 
 interface HtmlFileViewerProps {
-  html: string
   path: string
 }
 
-export function HtmlFileViewer({ html, path }: HtmlFileViewerProps) {
+export function HtmlFileViewer({ path }: HtmlFileViewerProps) {
+  const [state, setState] = useState<ViewerState>({ kind: 'loading' })
   const [iframeLoaded, setIframeLoaded] = useState(false)
 
   useEffect(() => {
+    let cancelled = false
+    setState({ kind: 'loading' })
     setIframeLoaded(false)
-  }, [path, html])
 
-  const showSpinner = !html || !iframeLoaded
+    ;(async () => {
+      try {
+        const stat = await window.ipc.invoke('workspace:stat', { path })
+        if (cancelled) return
+        if (stat.kind !== 'file') {
+          setState({ kind: 'error', message: 'Selected path is not a file.' })
+          return
+        }
+        if (stat.size > MAX_SIZE_BYTES) {
+          setState({ kind: 'tooLarge', sizeMB: stat.size / (1024 * 1024) })
+          return
+        }
+        const result = await window.ipc.invoke('workspace:readFile', { path })
+        if (cancelled) return
+        if (!result.data || result.data.trim() === '') {
+          setState({ kind: 'empty' })
+          return
+        }
+        setState({ kind: 'loaded', html: result.data })
+      } catch (err) {
+        if (cancelled) return
+        const message = err instanceof Error ? err.message : String(err)
+        setState({ kind: 'error', message })
+      }
+    })()
+
+    return () => {
+      cancelled = true
+    }
+  }, [path])
+
+  if (state.kind === 'error') {
+    return (
+      <div className="flex h-full w-full flex-col items-center justify-center gap-2 px-6 text-center text-muted-foreground">
+        <AlertCircleIcon className="size-6 text-destructive" />
+        <p className="text-sm font-medium text-foreground">Could not load preview</p>
+        <p className="max-w-md text-xs">{state.message}</p>
+        <p className="text-xs opacity-60">{path}</p>
+      </div>
+    )
+  }
+
+  if (state.kind === 'empty') {
+    return (
+      <div className="flex h-full w-full flex-col items-center justify-center gap-2 text-muted-foreground">
+        <FileTextIcon className="size-6" />
+        <p className="text-sm">This file is empty</p>
+      </div>
+    )
+  }
+
+  if (state.kind === 'tooLarge') {
+    return (
+      <div className="flex h-full w-full flex-col items-center justify-center gap-3 px-6 text-center text-muted-foreground">
+        <FileTextIcon className="size-6" />
+        <p className="text-sm font-medium text-foreground">File too large to preview</p>
+        <p className="text-xs">
+          {state.sizeMB.toFixed(1)} MB — preview limit is {(MAX_SIZE_BYTES / (1024 * 1024)).toFixed(0)} MB.
+        </p>
+        <button
+          type="button"
+          onClick={() => {
+            void window.ipc.invoke('shell:openPath', { path })
+          }}
+          className="inline-flex items-center gap-1.5 rounded-md border border-border bg-background px-3 py-1.5 text-xs font-medium text-foreground hover:bg-accent"
+        >
+          <ExternalLinkIcon className="size-3.5" />
+          Open in system
+        </button>
+      </div>
+    )
+  }
 
   return (
     <div className="relative h-full w-full">
-      {html && (
+      {state.kind === 'loaded' && (
         <iframe
           key={path}
-          srcDoc={html}
+          srcDoc={state.html}
           sandbox="allow-scripts"
           className="h-full w-full border-0 bg-white"
           title="HTML preview"
           onLoad={() => setIframeLoaded(true)}
         />
       )}
-      {showSpinner && (
+      {(state.kind === 'loading' || !iframeLoaded) && (
         <div className="absolute inset-0 flex flex-col items-center justify-center gap-3 bg-background text-muted-foreground">
           <Loader2Icon className="size-6 animate-spin" />
           <p className="text-sm">Rendering preview…</p>