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});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // TRY THIS: Try running your application with "flutter run". You'll see
        // the application has a purple toolbar. Then, without quitting the app,
        // try changing the seedColor in the colorScheme below to Colors.green
        // and then invoke "hot reload" (save your changes or press the "hot
        // reload" button in a Flutter-supported IDE, or press "r" if you used
        // the command line to start the app).
        //
        // Notice that the counter didn't reset back to zero; the application
        // state is not lost during the reload. To reset the state, use hot
        // restart instead.
        //
        // This works for code too, not just values: Most code changes can be
        // tested with just a hot reload.
        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});

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

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

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

  Future<void> _incrementCounter() async {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });

    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

      keyPair = await generateKeyPair();

      setState(() {
        // private to hex string
        // key = privateKey
        //     .map((byte) => byte.toRadixString(16).padLeft(2, '0'))
        //     .join('');

        if (keyPair != null) {
          key = encodePublicKey(keyPair!, comment: "leinelab-app-key");
        } else {
          key = "No key pair generated.";
        }
      });

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

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.

    final String outputText = _output.isNotEmpty
        ? 'Output: $_output'
        : 'Press the button to run a command.';

    final bodyComponentMain = Center(
      // Center is a layout widget. It takes a single child and positions it
      // in the middle of the parent.
      child: Column(
        // Column is also a layout widget. It takes a list of children and
        // arranges them vertically. By default, it sizes itself to fit its
        // children horizontally, and tries to be as tall as its parent.
        //
        // Column has various properties to control how it sizes itself and
        // how it positions its children. Here we use mainAxisAlignment to
        // center the children vertically; the main axis here is the vertical
        // axis because Columns are vertical (the cross axis would be
        // horizontal).
        //
        // TRY THIS: Invoke "debug painting" (choose the "Toggle Debug Paint"
        // action in the IDE, or press "p" in the console), to see the
        // wireframe for each widget.
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          Text('Current output:'),
          Text(outputText, style: Theme.of(context).textTheme.headlineMedium),
        ],
      ),
    );

    final bodyComponentInfo = Center(
      // Center is a layout widget. It takes a single child and positions it
      // in the middle of the parent.
      child: Column(
        // Column is also a layout widget. It takes a list of children and
        // arranges them vertically. By default, it sizes itself to fit its
        // children horizontally, and tries to be as tall as its parent.
        //
        // Column has various properties to control how it sizes itself and
        // how it positions its children. Here we use mainAxisAlignment to
        // center the children vertically; the main axis here is the vertical
        // axis because Columns are vertical (the cross axis would be
        // horizontal).
        //
        // TRY THIS: Invoke "debug painting" (choose the "Toggle Debug Paint"
        // action in the IDE, or press "p" in the console), to see the
        // wireframe for each widget.
        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(
        // TRY THIS: Try changing the color here to a specific color (to
        // Colors.amber, perhaps?) and trigger a hot reload to see the AppBar
        // change color while the other colors stay the same.
        backgroundColor: Colors.amber,
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: bodyComponent,
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.,
      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: () {
                // Update the state of the app
                // ...
                // Then close the drawer
                setState(() {
                  navIndex = 0; // Example of changing the navigation index
                });
                Navigator.pop(context);
              },
            ),
            ListTile(
              title: const Text('Info Page'),
              onTap: () {
                // Update the state of the app
                // ...
                // Then close the drawer
                setState(() {
                  navIndex = 1; // Example of changing the navigation index
                });
                Navigator.pop(context);
              },
            ),
          ],
        ),
      ),
    );
  }
}