/**
 * Update the specified resource in storage.
 */
public function update(Request $request, SuratMasuk $suratMasuk)
{
    $user = auth()->user();

    // Authorization: pembuat bisa update sebelum disposisi, admin bisa update apapun
    if (!$suratMasuk->canBeModifiedBy($user)) {
        return redirect()->back()->with('error', 'Anda tidak memiliki akses untuk mengupdate surat ini.');
    }

    // TU satuan: validasi tujuan harus ke atasan langsung (kecuali admin)
    if (($user->isTU() || $user->isOperatorTU()) && !$user->isSETUM() && !$user->isAdmin()) {
        $tujuanId = $request->input('tujuan_akhir_id');
        if ($tujuanId && $tujuanId != $user->superior_id) {
            return redirect()->back()->with('error', 'TU hanya dapat mengirim surat ke atasan langsung.');
        }
    }

    $action   = $request->input('action');
    $isDraft  = $action === 'draft';
    $isUpdate = $action === 'update';

    // Validasi ringan di Laravel untuk UX (pesan langsung tanpa round-trip Node)
    if ($isDraft) {
        $validated = $request->validate([
            'nomor_surat'     => 'nullable|string|max:255',
            'tanggal_surat'   => 'nullable|date',
            'asal_surat'      => 'nullable|string|max:255',
            'perihal'         => 'nullable|string',
            'kategori_id'     => 'nullable|exists:kategori_surat,id',
            'tujuan_akhir_id' => 'nullable|exists:users,id',
            'sifat'           => 'nullable|in:biasa,segera,sangat_segera,rahasia',
            'is_kilat'        => 'nullable|boolean',
            'keterangan'      => 'nullable|string',
            'file_surat'      => 'nullable|file|mimes:pdf|max:30720',
        ]);
    } elseif ($isUpdate) {
        $validated = $request->validate([
            'nomor_surat'   => 'nullable|string|max:255',
            'tanggal_surat' => 'nullable|date',
            'asal_surat'    => 'nullable|string|max:255',
            'perihal'       => 'nullable|string',
            'kategori_id'   => 'nullable|exists:kategori_surat,id',
            'sifat'         => 'nullable|in:biasa,segera,sangat_segera,rahasia',
            'is_kilat'      => 'nullable|boolean',
            'keterangan'    => 'nullable|string',
            'file_surat'    => 'nullable|file|mimes:pdf|max:30720',
        ]);
    } else {
        // Mode kirim
        $validated = $request->validate([
            'nomor_surat'     => 'required|string|max:255',
            'tanggal_surat'   => 'required|date',
            'asal_surat'      => 'required|string|max:255',
            'perihal'         => 'required|string',
            'kategori_id'     => 'required|exists:kategori_surat,id',
            'tujuan_akhir_id' => 'required|exists:users,id',
            'sifat'           => 'nullable|in:biasa,segera,sangat_segera,rahasia',
            'is_kilat'        => 'nullable|boolean',
            'keterangan'      => 'nullable|string',
            'file_surat'      => 'nullable|file|mimes:pdf|max:30720',
        ]);
    }

    $validated['is_kilat'] = $request->has('is_kilat') ? '1' : '0';

    try {
        $nodeApi = new NodeApiService();

        // Handle file upload ke S3 dahulu, lalu kirim path ke Node
        if ($request->hasFile('file_surat')) {
            $filePath = $request->file('file_surat')->store('surat-masuk', 's3');
            $validated['file_surat_path'] = $filePath;
        }

        $payload = array_filter([
            'nomor_surat'      => $validated['nomor_surat'] ?? null,
            'asal_surat'       => $validated['asal_surat'] ?? null,
            'perihal'          => $validated['perihal'] ?? null,
            'tanggal_surat'    => $validated['tanggal_surat'] ?? null,
            'kategori_id'      => $validated['kategori_id'] ?? null,
            'sifat'            => $validated['sifat'] ?? null,
            'is_kilat'         => $validated['is_kilat'],
            'keterangan'       => $validated['keterangan'] ?? null,
            'tujuan_akhir_id'  => $validated['tujuan_akhir_id'] ?? null,
            'file_surat_path'  => $validated['file_surat_path'] ?? null,
        ], fn($v) => !is_null($v));

        $response = $nodeApi->put("/api/surat-masuk/{$suratMasuk->id}", $payload);

        if (!$response->successful()) {
            $errorMsg = $response->json('message') ?? $response->body();
            return redirect()->back()->withInput()->with('error', 'Gagal: ' . $errorMsg);
        }

        $successMessage = $response->json('message') ?? 'Surat masuk berhasil diperbarui.';

        if ($isDraft) {
            return redirect()->route('surat-masuk.index')->with('success', $successMessage);
        }

        return redirect()->route('surat-masuk.show', $suratMasuk)->with('success', $successMessage);

    } catch (\Exception $e) {
        return redirect()->back()
            ->withInput()
            ->with('error', 'Gagal memperbarui surat masuk: ' . $e->getMessage());
    }
}