import 'dart:io';

import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'slide_controller.dart';

void main() => runApp(const PptRemoteApp());

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'PPT Remote',
      theme: ThemeData.dark(useMaterial3: true).copyWith(
        colorScheme: ColorScheme.fromSeed(
          seedColor: Colors.deepOrange,
          brightness: Brightness.dark,
        ),
      ),
      home: const ConnectScreen(),
    );
  }
}

// ─── Connect Screen ───────────────────────────────────────────────────────────

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

  @override
  State<ConnectScreen> createState() => _ConnectScreenState();
}

class _ConnectScreenState extends State<ConnectScreen> {
  final _hostController = TextEditingController(text: '192.168.1.100');
  final _portController = TextEditingController(text: '8765');

  @override
  void initState() {
    super.initState();
    _loadPrefs();
  }

  Future<void> _loadPrefs() async {
    final prefs = await SharedPreferences.getInstance();
    setState(() {
      _hostController.text = prefs.getString('host') ?? '192.168.1.100';
      _portController.text = prefs.getString('port') ?? '8765';
    });
  }

  bool _checking = false;
  String? _checkError;

  Future<void> _connect() async {
    final host = _hostController.text.trim();
    final port = _portController.text.trim();
    final portNum = int.tryParse(port) ?? 8765;

    setState(() {
      _checking = true;
      _checkError = null;
    });

    // Probe the HTTP endpoint before opening a WebSocket
    final reachable = await _checkServer(host, portNum);
    if (!mounted) return;

    if (!reachable) {
      setState(() {
        _checking = false;
        _checkError = 'Cannot reach $host:$portNum\n'
            'Make sure the server is running and both devices are on the same Wi-Fi.';
      });
      return;
    }

    final prefs = await SharedPreferences.getInstance();
    await prefs.setString('host', host);
    await prefs.setString('port', port);

    setState(() => _checking = false);
    if (!mounted) return;

    Navigator.of(context).push(MaterialPageRoute(
      builder: (_) => RemoteScreen(host: host, port: portNum),
    ));
  }

  /// Tries a plain TCP connection to host:port with a 3-second timeout.
  Future<bool> _checkServer(String host, int port) async {
    try {
      final socket = await Socket.connect(host, port,
          timeout: const Duration(seconds: 3));
      socket.destroy();
      return true;
    } catch (_) {
      return false;
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('PPT Remote')),
      body: Padding(
        padding: const EdgeInsets.all(24),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Icon(Icons.slideshow, size: 72, color: Colors.deepOrange),
            const SizedBox(height: 32),
            TextField(
              controller: _hostController,
              decoration: const InputDecoration(
                labelText: 'Server IP',
                border: OutlineInputBorder(),
                prefixIcon: Icon(Icons.computer),
              ),
              keyboardType: TextInputType.url,
            ),
            const SizedBox(height: 16),
            TextField(
              controller: _portController,
              decoration: const InputDecoration(
                labelText: 'Port',
                border: OutlineInputBorder(),
                prefixIcon: Icon(Icons.settings_ethernet),
              ),
              keyboardType: TextInputType.number,
            ),
            const SizedBox(height: 32),
            if (_checkError != null)
              Padding(
                padding: const EdgeInsets.only(bottom: 16),
                child: Row(
                  children: [
                    const Icon(Icons.error_outline, color: Colors.redAccent),
                    const SizedBox(width: 8),
                    Expanded(
                      child: Text(
                        _checkError!,
                        style: const TextStyle(color: Colors.redAccent),
                      ),
                    ),
                  ],
                ),
              ),
            FilledButton.icon(
              onPressed: _checking ? null : _connect,
              icon: _checking
                  ? const SizedBox(
                      width: 18,
                      height: 18,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : const Icon(Icons.wifi),
              label: Text(_checking ? 'Checking...' : 'Connect'),
              style: FilledButton.styleFrom(
                minimumSize: const Size.fromHeight(52),
              ),
            ),
          ],
        ),
      ),
    );
  }
}