feat(admin/exports): inline preview modal with copy-to-clipboard (#631)

Follow-up to #623. The Lightroom TXT export now shows the filename list
in a modal with a "Copy to clipboard" button instead of triggering a
.txt file download — saves the "open file → select all → copy" dance
admins were doing anyway. CSV export takes the same path (paste straight
into Sheets / Excel).

The modal keeps a "Download as file" button so admins who want the file
(sharing with colleagues, archiving, post-processing tooling) aren't
worse off than before — fully additive.

XMP (ZIP archive) and JSON exports keep their direct download path. A
textarea preview is the wrong UI for a binary archive, and JSON is
structured tool input where the file form is the natural mode.

Implementation:

- ExportPreviewModal — readonly textarea, copy + download buttons,
  monospace font for filename lists, click-to-select-all on the textarea
  for browsers that block clipboard writes (older Safari, hardened
  sandboxes — the catch falls through to a "select and copy manually"
  toast instead of silent failure).
- photosService.exportPhotosAsText — same backend endpoint as
  exportPhotos but resolves the blob.text() and returns
  { content, filename } instead of triggering a download. Preserves
  the existing exportPhotos for the XMP / JSON paths.
- PhotoExportMenu — PREVIEW_FORMATS = ['txt', 'csv']; non-preview
  formats keep the direct-download flow unchanged.
- EN + DE i18n entries.

No backend changes. No new endpoints. No breaking changes for callers
of photosService.exportPhotos.

frontend/src/components/admin/ExportPreviewModal.tsx

@@ -0,0 +1,129 @@
+import React, { useState } from 'react';
+import { X, Copy, Check, Download } from 'lucide-react';
+import { useTranslation } from 'react-i18next';
+import { toast } from 'react-toastify';
+import { Button, Card } from '../common';
+
+interface ExportPreviewModalProps {
+  format: 'txt' | 'csv';
+  content: string;
+  filename: string;
+  onClose: () => void;
+}
+
+/**
+ * Inline preview for text-based photo exports (#631).
+ *
+ * Daniel reported in #623 that the Lightroom TXT export was effectively
+ * unusable as a file download — admins re-open the file, select-all, copy,
+ * paste into Lightroom's search field. He suggested a modal with a
+ * copy-to-clipboard button as a follow-up. Same workflow applies to the
+ * CSV export (paste straight into Sheets / Excel).
+ *
+ * The modal preserves the file-download path so admins who want the file
+ * (sharing with colleagues, archiving, post-processing tooling) aren't
+ * worse off. XMP (ZIP archive) and JSON exports stay direct downloads —
+ * neither makes sense as a textarea preview.
+ */
+export const ExportPreviewModal: React.FC<ExportPreviewModalProps> = ({
+  format,
+  content,
+  filename,
+  onClose,
+}) => {
+  const { t } = useTranslation();
+  const [copied, setCopied] = useState(false);
+
+  const handleCopy = async () => {
+    try {
+      await navigator.clipboard.writeText(content);
+      setCopied(true);
+      toast.success(t('export.preview.copied', 'Copied to clipboard.'));
+      setTimeout(() => setCopied(false), 2000);
+    } catch {
+      // Some browsers (older Safari, hardened sandboxes) reject
+      // clipboard writes. Fall back to manual select-all so the admin
+      // can Cmd/Ctrl+C themselves; doesn't fail silently.
+      toast.error(
+        t('export.preview.copyFailed', 'Clipboard write blocked. Select the text and copy manually.'),
+      );
+    }
+  };
+
+  const handleDownload = () => {
+    const blob = new Blob([content], {
+      type: format === 'csv' ? 'text/csv;charset=utf-8' : 'text/plain;charset=utf-8',
+    });
+    const url = window.URL.createObjectURL(blob);
+    const link = document.createElement('a');
+    link.href = url;
+    link.download = filename;
+    document.body.appendChild(link);
+    link.click();
+    document.body.removeChild(link);
+    window.URL.revokeObjectURL(url);
+  };
+
+  const titleKey = format === 'csv' ? 'export.preview.titleCsv' : 'export.preview.titleTxt';
+  const titleDefault = format === 'csv' ? 'CSV export' : 'Lightroom filename list';
+  const helpKey = format === 'csv'
+    ? 'export.preview.helpCsv'
+    : 'export.preview.helpTxt';
+  const helpDefault = format === 'csv'
+    ? 'Paste into a spreadsheet (Google Sheets, Excel, Numbers) — the first row is the column header.'
+    : 'Paste into Lightroom\'s filename search. The list is comma-separated with no extension so it matches a catalog that holds RAW files.';
+
+  return (
+    <div className="fixed inset-0 bg-black/50 flex items-center justify-center z-50 p-4">
+      <Card className="max-w-2xl w-full">
+        <div className="flex items-center justify-between mb-3">
+          <h2 className="text-xl font-semibold text-neutral-900 dark:text-neutral-100">
+            {t(titleKey, titleDefault)}
+          </h2>
+          <button
+            onClick={onClose}
+            className="text-neutral-400 hover:text-neutral-600 dark:hover:text-neutral-300"
+            aria-label={t('common.close', 'Close')}
+          >
+            <X className="w-5 h-5" />
+          </button>
+        </div>
+
+        <p className="text-sm text-neutral-600 dark:text-neutral-400 mb-3">
+          {t(helpKey, helpDefault)}
+        </p>
+
+        <textarea
+          readOnly
+          value={content}
+          onClick={(e) => (e.target as HTMLTextAreaElement).select()}
+          className="w-full h-64 p-3 rounded-md border border-neutral-300 dark:border-neutral-600 bg-neutral-50 dark:bg-neutral-900 text-sm font-mono text-neutral-900 dark:text-neutral-100 mb-4"
+        />
+
+        <div className="flex gap-2 justify-between items-center">
+          <span className="text-xs text-neutral-500 dark:text-neutral-400 font-mono truncate">
+            {filename}
+          </span>
+          <div className="flex gap-2">
+            <Button
+              variant="outline"
+              onClick={handleDownload}
+              leftIcon={<Download className="w-4 h-4" />}
+            >
+              {t('export.preview.download', 'Download as file')}
+            </Button>
+            <Button
+              variant="primary"
+              onClick={handleCopy}
+              leftIcon={copied ? <Check className="w-4 h-4" /> : <Copy className="w-4 h-4" />}
+            >
+              {copied
+                ? t('export.preview.copiedShort', 'Copied')
+                : t('export.preview.copyButton', 'Copy to clipboard')}
+            </Button>
+          </div>
+        </div>
+      </Card>
+    </div>
+  );
+};

frontend/src/components/admin/PhotoExportMenu.tsx

@@ -4,6 +4,13 @@ import { useTranslation } from 'react-i18next';
 import { useMutation } from '@tanstack/react-query';
 import { toast } from 'react-toastify';
 import { photosService, ExportOptions, FeedbackFilters } from '../../services/photos.service';
+import { ExportPreviewModal } from './ExportPreviewModal';
+
+// TXT + CSV render through the preview modal (with copy-to-clipboard and a
+// fallback download button). XMP is a ZIP archive — no textarea preview makes
+// sense. JSON stays a direct download because operators consuming it want a
+// file for tooling. See #631.
+const PREVIEW_FORMATS: ReadonlyArray<'txt' | 'csv'> = ['txt', 'csv'];
 
 interface PhotoExportMenuProps {
   eventId: number;
@@ -47,6 +54,11 @@ export const PhotoExportMenu: React.FC<PhotoExportMenuProps> = ({
 }) => {
   const { t } = useTranslation();
   const [isOpen, setIsOpen] = useState(false);
+  const [preview, setPreview] = useState<{
+    format: 'txt' | 'csv';
+    content: string;
+    filename: string;
+  } | null>(null);
 
   const exportMutation = useMutation({
     mutationFn: (options: ExportOptions) => photosService.exportPhotos(eventId, options),
@@ -59,6 +71,21 @@ export const PhotoExportMenu: React.FC<PhotoExportMenuProps> = ({
     }
   });
 
+  const previewMutation = useMutation({
+    mutationFn: ({ options, format }: { options: ExportOptions; format: 'txt' | 'csv' }) =>
+      photosService.exportPhotosAsText(eventId, options).then((result) => ({
+        ...result,
+        format,
+      })),
+    onSuccess: (result) => {
+      setPreview(result);
+      setIsOpen(false);
+    },
+    onError: (error: Error) => {
+      toast.error(t('export.error', 'Export failed: ') + error.message);
+    },
+  });
+
   const handleExport = (format: 'txt' | 'csv' | 'xmp' | 'json') => {
     const options: ExportOptions = {
       format,
@@ -96,7 +123,11 @@ export const PhotoExportMenu: React.FC<PhotoExportMenuProps> = ({
       };
     }
 
-    exportMutation.mutate(options);
+    if ((PREVIEW_FORMATS as readonly string[]).includes(format)) {
+      previewMutation.mutate({ options, format: format as 'txt' | 'csv' });
+    } else {
+      exportMutation.mutate(options);
+    }
   };
 
   const hasSelection = selectedPhotoIds.length > 0;
@@ -108,13 +139,14 @@ export const PhotoExportMenu: React.FC<PhotoExportMenuProps> = ({
   );
 
   const isDisabled = disabled || (!hasSelection && !hasFilters);
+  const isWorking = exportMutation.isPending || previewMutation.isPending;
 
   return (
     <div className="relative">
       <button
         type="button"
         onClick={() => setIsOpen(!isOpen)}
-        disabled={isDisabled || exportMutation.isPending}
+        disabled={isDisabled || isWorking}
         className={`
           inline-flex items-center gap-2 px-4 py-2 rounded-lg border font-medium text-sm
           transition-colors
@@ -124,7 +156,7 @@ export const PhotoExportMenu: React.FC<PhotoExportMenuProps> = ({
           }
         `}
       >
-        {exportMutation.isPending ? (
+        {isWorking ? (
           <Loader2 className="w-4 h-4 animate-spin" />
         ) : (
           <Download className="w-4 h-4" />
@@ -162,7 +194,7 @@ export const PhotoExportMenu: React.FC<PhotoExportMenuProps> = ({
                   <button
                     key={format.value}
                     onClick={() => handleExport(format.value as 'txt' | 'csv' | 'xmp' | 'json')}
-                    disabled={exportMutation.isPending}
+                    disabled={isWorking}
                     className="w-full flex items-start gap-3 px-3 py-2 rounded-md hover:bg-neutral-50 dark:hover:bg-neutral-700 text-left transition-colors"
                   >
                     <Icon className="w-5 h-5 text-neutral-500 dark:text-neutral-400 mt-0.5" />
@@ -187,6 +219,15 @@ export const PhotoExportMenu: React.FC<PhotoExportMenuProps> = ({
           {t('export.hint', 'Select photos or apply filters to export')}
         </p>
       )}
+
+      {preview && (
+        <ExportPreviewModal
+          format={preview.format}
+          content={preview.content}
+          filename={preview.filename}
+          onClose={() => setPreview(null)}
+        />
+      )}
     </div>
   );
 };

frontend/src/components/admin/index.ts

@@ -19,6 +19,7 @@ export { PhotoFilters } from './PhotoFilters';
 export { PasswordResetModal } from './PasswordResetModal';
 export { PublishGalleryDialog } from './PublishGalleryDialog';
 export { DuplicateEventDialog } from './DuplicateEventDialog';
+export { ExportPreviewModal } from './ExportPreviewModal';
 export { AdminAuthenticatedImage } from './AdminAuthenticatedImage';
 export { AdminAuthenticatedVideo } from './AdminAuthenticatedVideo';
 export { ThemeCustomizerEnhanced } from './ThemeCustomizerEnhanced';

frontend/src/i18n/locales/de.json

@@ -2920,7 +2920,18 @@
     "exportFiltered": "Gefilterte Fotos exportieren",
     "hint": "Fotos auswählen oder Filter anwenden zum Exportieren",
     "exportSelected_one": "{{count}} ausgewähltes exportieren",
-    "exportSelected_other": "{{count}} ausgewählte exportieren"
+    "exportSelected_other": "{{count}} ausgewählte exportieren",
+    "preview": {
+      "titleTxt": "Dateinamen-Liste für Lightroom",
+      "titleCsv": "CSV-Export",
+      "helpTxt": "In das Lightroom-Dateinamensuchfeld einfügen. Die Liste ist kommagetrennt und ohne Dateiendung, damit sie auch zu einem Katalog mit RAW-Dateien passt.",
+      "helpCsv": "In eine Tabellenkalkulation einfügen (Google Sheets, Excel, Numbers) – die erste Zeile ist die Spaltenüberschrift.",
+      "copyButton": "In die Zwischenablage kopieren",
+      "copiedShort": "Kopiert",
+      "copied": "In die Zwischenablage kopiert.",
+      "copyFailed": "Zugriff auf die Zwischenablage blockiert. Bitte den Text markieren und manuell kopieren.",
+      "download": "Als Datei herunterladen"
+    }
   },
   "clientAccess": {
     "title": "Kundenzugang",

frontend/src/i18n/locales/en.json

@@ -2989,7 +2989,18 @@
     "exportFiltered": "Export filtered photos",
     "hint": "Select photos or apply filters to export",
     "exportSelected_one": "Export {{count}} selected",
-    "exportSelected_other": "Export {{count}} selected"
+    "exportSelected_other": "Export {{count}} selected",
+    "preview": {
+      "titleTxt": "Lightroom filename list",
+      "titleCsv": "CSV export",
+      "helpTxt": "Paste into Lightroom's filename search. The list is comma-separated with no extension so it matches a catalog that holds RAW files.",
+      "helpCsv": "Paste into a spreadsheet (Google Sheets, Excel, Numbers) — the first row is the column header.",
+      "copyButton": "Copy to clipboard",
+      "copiedShort": "Copied",
+      "copied": "Copied to clipboard.",
+      "copyFailed": "Clipboard write blocked. Select the text and copy manually.",
+      "download": "Download as file"
+    }
   },
   "photoSort": {
     "defaultSort": "Default Photo Sort",

frontend/src/services/photos.service.ts

@@ -295,6 +295,35 @@ class PhotosService {
     window.URL.revokeObjectURL(url);
   }
 
+  // Same endpoint as `exportPhotos` but returns the text content + filename
+  // instead of triggering a download. Used by the ExportPreviewModal (#631)
+  // for TXT / CSV formats where the admin wants to paste rather than save.
+  // XMP (ZIP archive) and JSON keep using exportPhotos — a textarea is the
+  // wrong UI for binary archives and structured tool input.
+  async exportPhotosAsText(
+    eventId: number,
+    options: ExportOptions
+  ): Promise<{ content: string; filename: string }> {
+    const response = await api.post(
+      `/admin/photo-export/${eventId}/export`,
+      options,
+      { responseType: 'blob' }
+    );
+
+    const contentDisposition = response.headers['content-disposition'];
+    let filename = `export_${Date.now()}`;
+    if (contentDisposition) {
+      const filenameMatch = contentDisposition.match(/filename="?([^";\n]+)"?/);
+      if (filenameMatch) {
+        filename = filenameMatch[1];
+      }
+    }
+
+    const blob = response.data as Blob;
+    const content = await blob.text();
+    return { content, filename };
+  }
+
   async getExportFormats(): Promise<ExportFormat[]> {
     const response = await api.get('/admin/photo-export/export-formats');
     return response.data.data;