Support multi-file upload for municipal receipts

Upload panel now accepts multiple PDFs at once (drag-drop or file picker),
shows a file queue with individual remove buttons, and displays per-file
results after processing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/pages/ServiciosMunicipales.tsx

@@ -150,10 +150,10 @@ export default function ServiciosMunicipales() {
   const [loading, setLoading] = useState(true);
 
   // Upload state
-  const [uploadedFile, setUploadedFile] = useState<File | null>(null);
+  const [uploadedFiles, setUploadedFiles] = useState<File[]>([]);
   const [isDragging, setIsDragging] = useState(false);
   const [isUploading, setIsUploading] = useState(false);
-  const [uploadResult, setUploadResult] = useState<MunicipalReceiptUploadResult | null>(null);
+  const [uploadResults, setUploadResults] = useState<MunicipalReceiptUploadResult[]>([]);
   const fileInputRef = useRef<HTMLInputElement>(null);
 
   const loadData = useCallback(async () => {
@@ -205,34 +205,41 @@ export default function ServiciosMunicipales() {
     : 0;
 
   // Upload handlers
-  const handleFile = useCallback((files: FileList | null) => {
+  const handleFiles = useCallback((files: FileList | null) => {
     if (!files) return;
-    const pdf = Array.from(files).find((f) => f.type === 'application/pdf');
-    if (pdf) {
-      setUploadedFile(pdf);
-      setUploadResult(null);
+    const pdfs = Array.from(files).filter((f) => f.type === 'application/pdf');
+    if (pdfs.length > 0) {
+      setUploadedFiles((prev) => [...prev, ...pdfs]);
+      setUploadResults([]);
     }
   }, []);
 
+  const removeFile = (index: number) => {
+    setUploadedFiles((prev) => prev.filter((_, i) => i !== index));
+  };
+
   const handleUpload = async () => {
-    if (!uploadedFile) return;
+    if (uploadedFiles.length === 0) return;
     setIsUploading(true);
-    setUploadResult(null);
-    try {
-      const { data } = await uploadMunicipalReceipt(uploadedFile);
-      setUploadResult(data);
-      setUploadedFile(null);
-      await loadData();
-    } catch (err) {
-      setUploadResult({
-        imported: 0,
-        updated: 0,
-        errors: [err instanceof Error ? err.message : 'Error al subir archivo'],
-        receipt: null,
-      });
-    } finally {
-      setIsUploading(false);
+    setUploadResults([]);
+    const results: MunicipalReceiptUploadResult[] = [];
+    for (const file of uploadedFiles) {
+      try {
+        const { data } = await uploadMunicipalReceipt(file);
+        results.push(data);
+      } catch (err) {
+        results.push({
+          imported: 0,
+          updated: 0,
+          errors: [`${file.name}: ${err instanceof Error ? err.message : 'Error al subir'}`],
+          receipt: null,
+        });
+      }
     }
+    setUploadResults(results);
+    setUploadedFiles([]);
+    await loadData();
+    setIsUploading(false);
   };
 
   const formatFileSize = (bytes: number): string => {
@@ -511,7 +518,7 @@ export default function ServiciosMunicipales() {
       <section className="space-y-3">
         <h2 className="text-base font-semibold font-heading flex items-center gap-2 text-muted-foreground uppercase tracking-wider">
           <FileText className="w-4 h-4" />
-          Subir Recibo
+          Subir Recibos
         </h2>
         <Card>
           <CardContent className="p-6 space-y-4">
@@ -519,12 +526,12 @@ export default function ServiciosMunicipales() {
             <div
               onDragOver={(e) => { e.preventDefault(); setIsDragging(true); }}
               onDragLeave={(e) => { e.preventDefault(); setIsDragging(false); }}
-              onDrop={(e) => { e.preventDefault(); setIsDragging(false); handleFile(e.dataTransfer.files); }}
+              onDrop={(e) => { e.preventDefault(); setIsDragging(false); handleFiles(e.dataTransfer.files); }}
               onClick={() => fileInputRef.current?.click()}
               role="button"
               tabIndex={0}
               onKeyDown={(e) => e.key === 'Enter' && fileInputRef.current?.click()}
-              aria-label="Seleccionar archivo PDF"
+              aria-label="Seleccionar archivos PDF"
               className={[
                 'border-2 border-dashed rounded-lg p-8',
                 'flex flex-col items-center justify-center gap-3',
@@ -541,11 +548,11 @@ export default function ServiciosMunicipales() {
               <div className="text-center">
                 <p className="text-sm font-medium">
                   {isDragging
-                    ? 'Suelta el archivo aquí'
-                    : 'Arrastra el PDF aquí o toca para seleccionar'}
+                    ? 'Suelta los archivos aquí'
+                    : 'Arrastra PDFs aquí o toca para seleccionar'}
                 </p>
                 <p className="text-xs text-muted-foreground mt-1">
-                  Solo archivos PDF · Recibo Municipal de Belén
+                  Solo archivos PDF · Múltiples archivos soportados
                 </p>
               </div>
             </div>
@@ -554,34 +561,48 @@ export default function ServiciosMunicipales() {
               ref={fileInputRef}
               type="file"
               accept="application/pdf"
+              multiple
               className="hidden"
-              onChange={(e) => handleFile(e.target.files)}
+              onChange={(e) => handleFiles(e.target.files)}
             />
 
-            {/* Selected file */}
-            {uploadedFile && (
-              <div className="flex items-center justify-between gap-3 p-2.5 rounded-lg bg-muted/50 border border-border">
-                <div className="flex items-center gap-2.5 min-w-0">
-                  <FileText className="w-4 h-4 text-muted-foreground flex-shrink-0" />
-                  <div className="min-w-0">
-                    <p className="text-sm font-medium truncate">{uploadedFile.name}</p>
-                    <p className="text-xs text-muted-foreground">{formatFileSize(uploadedFile.size)}</p>
-                  </div>
+            {/* File list */}
+            {uploadedFiles.length > 0 && (
+              <div className="space-y-2">
+                <p className="text-sm text-muted-foreground font-medium">
+                  {uploadedFiles.length}{' '}
+                  {uploadedFiles.length === 1 ? 'archivo en cola' : 'archivos en cola'}
+                </p>
+                <div className="space-y-1.5">
+                  {uploadedFiles.map((file, i) => (
+                    <div
+                      key={i}
+                      className="flex items-center justify-between gap-3 p-2.5 rounded-lg bg-muted/50 border border-border"
+                    >
+                      <div className="flex items-center gap-2.5 min-w-0">
+                        <FileText className="w-4 h-4 text-muted-foreground flex-shrink-0" />
+                        <div className="min-w-0">
+                          <p className="text-sm font-medium truncate">{file.name}</p>
+                          <p className="text-xs text-muted-foreground">{formatFileSize(file.size)}</p>
+                        </div>
+                      </div>
+                      <button
+                        onClick={() => removeFile(i)}
+                        className="flex-shrink-0 p-1 rounded hover:bg-destructive/10 hover:text-destructive transition-colors cursor-pointer focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
+                        aria-label={`Eliminar ${file.name}`}
+                      >
+                        <X className="w-3.5 h-3.5" />
+                      </button>
+                    </div>
+                  ))}
                 </div>
-                <button
-                  onClick={() => setUploadedFile(null)}
-                  className="flex-shrink-0 p-1 rounded hover:bg-destructive/10 hover:text-destructive transition-colors cursor-pointer focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
-                  aria-label={`Eliminar ${uploadedFile.name}`}
-                >
-                  <X className="w-3.5 h-3.5" />
-                </button>
               </div>
             )}
 
             {/* Submit */}
             <Button
               onClick={handleUpload}
-              disabled={!uploadedFile || isUploading}
+              disabled={uploadedFiles.length === 0 || isUploading}
               className="w-full"
             >
               {isUploading ? (
@@ -589,43 +610,48 @@ export default function ServiciosMunicipales() {
               ) : (
                 <Upload className="w-4 h-4 mr-2" />
               )}
-              {isUploading ? 'Extrayendo datos...' : 'Subir Recibo'}
+              {isUploading ? 'Extrayendo datos...' : `Subir ${uploadedFiles.length > 1 ? `${uploadedFiles.length} Recibos` : 'Recibo'}`}
             </Button>
 
-            {/* Upload result */}
-            {uploadResult && (
-              <div
-                className={[
-                  'rounded-lg border p-4 space-y-2',
-                  uploadResult.errors.length > 0 && !uploadResult.receipt
-                    ? 'border-destructive/50 bg-destructive/5'
-                    : 'border-emerald-500/50 bg-emerald-500/5',
-                ].join(' ')}
-              >
-                <div className="flex items-center gap-2">
-                  {uploadResult.receipt ? (
-                    <CheckCircle2 className="w-4 h-4 text-emerald-500" />
-                  ) : (
-                    <AlertTriangle className="w-4 h-4 text-amber-500" />
-                  )}
-                  <span className="text-sm font-medium">
-                    {uploadResult.imported > 0 && 'Recibo importado'}
-                    {uploadResult.updated > 0 && 'Recibo actualizado'}
-                    {!uploadResult.receipt && 'Error al procesar'}
-                  </span>
-                </div>
-                {uploadResult.receipt && (
-                  <div className="flex items-center justify-between text-xs">
-                    <span className="text-muted-foreground">
-                      {periodLabel(uploadResult.receipt.period)}
-                    </span>
-                    <span data-sensitive className="font-mono font-medium">
-                      {formatCRC(uploadResult.receipt.total)}
-                    </span>
+            {/* Upload results */}
+            {uploadResults.length > 0 && (
+              <div className="space-y-2">
+                {uploadResults.map((result, i) => (
+                  <div
+                    key={i}
+                    className={[
+                      'rounded-lg border p-3 space-y-1',
+                      result.errors.length > 0 && !result.receipt
+                        ? 'border-destructive/50 bg-destructive/5'
+                        : 'border-emerald-500/50 bg-emerald-500/5',
+                    ].join(' ')}
+                  >
+                    <div className="flex items-center gap-2">
+                      {result.receipt ? (
+                        <CheckCircle2 className="w-4 h-4 text-emerald-500 flex-shrink-0" />
+                      ) : (
+                        <AlertTriangle className="w-4 h-4 text-amber-500 flex-shrink-0" />
+                      )}
+                      <span className="text-sm font-medium">
+                        {result.imported > 0 && 'Recibo importado'}
+                        {result.updated > 0 && 'Recibo actualizado'}
+                        {!result.receipt && 'Error al procesar'}
+                      </span>
+                    </div>
+                    {result.receipt && (
+                      <div className="flex items-center justify-between text-xs pl-6">
+                        <span className="text-muted-foreground">
+                          {periodLabel(result.receipt.period)}
+                        </span>
+                        <span data-sensitive className="font-mono font-medium">
+                          {formatCRC(result.receipt.total)}
+                        </span>
+                      </div>
+                    )}
+                    {result.errors.map((err, j) => (
+                      <p key={j} className="text-xs text-destructive pl-6">{err}</p>
+                    ))}
                   </div>
-                )}
-                {uploadResult.errors.map((err, i) => (
-                  <p key={i} className="text-xs text-destructive">{err}</p>
                 ))}
               </div>
             )}