feat: Add CSV download functionality for filtered dataset entries

src/app/api/download-metadata-csv/route.ts

@@ -0,0 +1,53 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { downloadFilteredEntries } from '@/app/actions/download-filtered-entries';
+import { requireAdmin } from '@/lib/auth';
+
+interface FilterParams {
+  speakerId?: string;
+  modelName?: string;
+  dialect?: string;
+  iteration?: number;
+  utteranceId?: string;
+}
+
+export async function POST(request: NextRequest) {
+  try {
+    const resultAdmin = await requireAdmin();
+    if (!resultAdmin.authenticated || !resultAdmin.admin) {
+      return NextResponse.json(
+        { error: 'Unauthorized' },
+        { status: 401 }
+      );
+    }
+
+    const body = await request.json();
+    const { datasetId, filters } = body;
+
+    if (!datasetId) {
+      return NextResponse.json(
+        { error: 'datasetId is required' },
+        { status: 400 }
+      );
+    }
+
+    // Get filtered entries data from server action
+    const result = await downloadFilteredEntries(datasetId, filters || {});
+
+    const fileName = `dataset-${datasetId}-metadata-${new Date().toISOString().split('T')[0]}.csv`;
+
+    return new NextResponse(result.csvContent, {
+      status: 200,
+      headers: {
+        'Content-Type': 'text/csv',
+        'Content-Disposition': `attachment; filename="${fileName}"`,
+        'Content-Length': Buffer.byteLength(result.csvContent).toString(),
+      },
+    });
+  } catch (error) {
+    console.error('Error downloading CSV:', error);
+    return NextResponse.json(
+      { error: 'Failed to download CSV file' },
+      { status: 500 }
+    );
+  }
+}