import 'dart:convert';
import 'dart:io';

import 'package:dartssh2/dartssh2.dart';
import 'package:flutter/material.dart';

// for ed2219 key generation
import 'package:cryptography/cryptography.dart';
import 'package:flutter/services.dart';

// secret storage
import 'package:flutter_secure_storage/flutter_secure_storage.dart';

void main() {
  runApp(const MyApp());
}

Future<OpenSSHEd25519KeyPair> generateKeyPair() async {
  final algorithm = Ed25519();

  // Generate a key pair
  final cryptographyKeyPair = await algorithm.newKeyPair();

  final privateKey = await cryptographyKeyPair.extractPrivateKeyBytes();
  final publicKey = (await cryptographyKeyPair.extractPublicKey()).bytes;

  final dartsshKeyPair = OpenSSHEd25519KeyPair(
    Uint8List.fromList(publicKey),
    Uint8List.fromList(privateKey + publicKey),
    "",
  );

  return dartsshKeyPair;
}

String encodePublicKey(OpenSSHEd25519KeyPair keyPair, {String comment = ''}) {
  final publicKeyBytes = keyPair.toPublicKey().encode();
  return "ssh-ed25519 ${base64.encode(publicKeyBytes)} $comment";
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
      ),
      home: const MyHomePage(title: 'LeineLab e.V. Key App'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int navIndex = 0;
  OpenSSHEd25519KeyPair? keyPair;
  String _output = '';
  String key = '';

  Future<void> _incrementCounter() async {
    if (navIndex == 0) {
      SSHSocket? socket;

      try {
        socket = await SSHSocket.connect(
          '192.168.2.123',
          22,
          timeout: const Duration(seconds: 0, milliseconds: 500),
        );
      } on SocketException {
        setState(() {
          _output = "SocketException: Could not connect to the server.";
        });
        return;
      }

      try {
        final client = SSHClient(
          socket,
          username: 'test',
          //onPasswordRequest: () => '123456',
          identities: List.of(keyPair != null ? [keyPair!] : []),
        );

        final uptime = await client.run('uptime');
        setState(() {
          _output = utf8.decode(uptime);
        });
      } catch (e) {
        setState(() {
          _output = "Error: $e";
        });
        return;
      }
    } else {
      // Generate a key pair

      final generatedKeyPair =
          await generateKeyPair(); // local variable avoids downcast to ? ptr
      keyPair = generatedKeyPair;

      setState(() {
        key = encodePublicKey(generatedKeyPair, comment: "leinelab-app-key");
      });

      await SystemChannels.platform.invokeMethod<void>(
        'Clipboard.setData',
        <String, dynamic>{'text': key},
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    final String outputText = _output.isNotEmpty
        ? 'Output: $_output'
        : 'Press the button to run a command.';

    final bodyComponentMain = Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          Text('Current output:'),
          Text(outputText, style: Theme.of(context).textTheme.headlineMedium),
        ],
      ),
    );

    final bodyComponentInfo = Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[Center(child: Text('Info\n\n$key'))],
      ),
    );

    var bodyComponent = bodyComponentMain;

    if (navIndex == 0) {
      // Main page
      bodyComponent = bodyComponentMain;
    } else if (navIndex == 1) {
      // Info page
      bodyComponent = bodyComponentInfo;
    } else {
      throw Exception('Unknown navIndex: $navIndex');
    }

    return Scaffold(
      appBar: AppBar(backgroundColor: Colors.amber, title: Text(widget.title)),
      body: bodyComponent,
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ),
      drawer: Drawer(
        child: ListView(
          padding: EdgeInsets.zero,
          children: <Widget>[
            DrawerHeader(
              decoration: BoxDecoration(color: Colors.amber),
              child: Text(
                widget.title,
                style: TextStyle(color: Colors.black, fontSize: 24),
              ),
            ),
            ListTile(
              title: const Text('Main Page'),
              onTap: () {
                setState(() {
                  navIndex = 0;
                });
                Navigator.pop(context);
              },
            ),
            ListTile(
              title: const Text('Info Page'),
              onTap: () {
                setState(() {
                  navIndex = 1;
                });
                Navigator.pop(context);
              },
            ),
          ],
        ),
      ),
    );
  }
}