// export_privateKey.dart

import 'package:flutter/material.dart';
import 'dart:typed_data';
import 'dart:convert';
import 'package:pointycastle/export.dart' as crypto;
import 'package:file_picker/file_picker.dart';

class ExportationClePriveePage extends StatefulWidget {
  const ExportationClePriveePage({super.key});

  @override
  _ExportationClePriveePageState createState() => _ExportationClePriveePageState();
}

class _ExportationClePriveePageState extends State<ExportationClePriveePage> {
  final TextEditingController _passwordController = TextEditingController();

  Future<void> _exportPrivateKey() async {
    // Replace with your actual private key retrieval logic
    final String privateKeyPem = 'Votre clé privée ici';

    // Get the password from the user input
    final password = _passwordController.text;
    if (password.isEmpty) {
      // Show error message
      return;
    }

    // Encrypt the private key using AES-256
    final encryptedData = _encryptPrivateKey(privateKeyPem, password);

    // Let the user pick a file location
    final outputFile = await FilePicker.platform.saveFile(
      dialogTitle: 'Enregistrer la clé privée chiffrée',
      fileName: 'private_key_encrypted.aes',
    );

    if (outputFile != null) {
      // Write the encrypted data to the file
      // Use appropriate file I/O methods (not shown here)
      // ...
      // Show a confirmation dialog or message
      showDialog(
        context: context,
        builder: (context) => AlertDialog(
          title: const Text('Clé Exportée'),
          content: const Text('La clé privée chiffrée a été exportée avec succès.'),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(context),
              child: const Text('OK'),
            ),
          ],
        ),
      );
    }
  }

  Uint8List _encryptPrivateKey(String privateKey, String password) {
    // Encryption logic using AES-256
    final key = crypto.PBKDF2KeyDerivator(crypto.HMac(crypto.SHA256Digest(), 64))
        .process(Uint8List.fromList(utf8.encode(password)));

    final params = crypto.PaddedBlockCipherParameters(
      crypto.ParametersWithIV(crypto.KeyParameter(key), Uint8List(16)), // Initialization Vector
      null,
    );
    final cipher = crypto.PaddedBlockCipher('AES/CBC/PKCS7');
    cipher.init(true, params);

    final input = Uint8List.fromList(utf8.encode(privateKey));
    final output = cipher.process(input);

    return output;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.black,
      appBar: AppBar(
        title: const Text('Exportation de la Clé Privée'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          children: [
            const Text(
              'Entrez un mot de passe pour chiffrer la clé privée:',
              style: TextStyle(color: Colors.white),
            ),
            TextField(
              controller: _passwordController,
              obscureText: true,
              style: const TextStyle(color: Colors.white),
              decoration: const InputDecoration(
                hintText: 'Mot de passe',
                hintStyle: TextStyle(color: Colors.grey),
              ),
            ),
            const SizedBox(height: 20),
            ElevatedButton(
              onPressed: _exportPrivateKey,
              child: const Text('Exporter la Clé Privée Chiffrée'),
            ),
          ],
        ),
      ),
    );
  }
}