import 'dart:async';
import 'package:flutter/material.dart';
import 'package:votianlt_app/services/developer.dart' as developer;
import 'package:votianlt_app/services/websocket_service.dart';
import 'package:votianlt_app/services/dart_mq.dart';

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

  @override
  State<OfflineBanner> createState() => _OfflineBannerState();
}

class _OfflineBannerState extends State<OfflineBanner> {
  final StompService _stompService = StompService();
  DartMQSubscription? _connSub;
  Timer? _countdownTimer;
  int _secondsToRetry = 15;
  bool _hadConnection = false; // Track if we ever had a successful connection

  @override
  void initState() {
    super.initState();
    // Check if we're already connected (e.g., coming back to this screen)
    _hadConnection = _stompService.isConnected && _stompService.isAuthenticated;
    // Initialize countdown based on current connection state
    _onConnectionChange(_stompService.isConnected && _stompService.isAuthenticated);
    _connSub = DartMQ().subscribe<bool>(MQTopics.connectionStatus, _onConnectionChange);
  }

  void _onConnectionChange(bool isConnected) {
    if (!mounted) return;
    if (isConnected) {
      _hadConnection = true; // Mark that we had a successful connection
      _stopCountdown();
      setState(() {});
    } else {
      _startCountdown();
    }
  }

  void _startCountdown() {
    _stopCountdown();
    setState(() {
      _secondsToRetry = 15;
    });
    _countdownTimer = Timer.periodic(const Duration(seconds: 1), (_) async {
      if (!mounted) return;
      if (_stompService.isConnected) {
        _stopCountdown();
        return;
      }

      // Decrement until 0, then attempt reconnect
      if (_secondsToRetry > 1) {
        setState(() {
          _secondsToRetry = _secondsToRetry - 1;
        });
        return;
      }

      // Show 0 for one tick and try to reconnect now
      setState(() {
        _secondsToRetry = 0;
      });

      try {
        // Only auto-reconnect if we already know the target; discovery remains user-initiated
        await _stompService.connect();
      } catch (e, stackTrace) {
        developer.log('Auto-reconnect attempt failed: $e', name: 'OfflineBanner');
        developer.log('Stack trace: $stackTrace', name: 'OfflineBanner');
      }

      if (!mounted) return;
      if (!_stompService.isConnected) {
        // Still offline -> reset countdown for next attempt
        setState(() {
          _secondsToRetry = 15;
        });
      }
    });
  }

  void _stopCountdown() {
    _countdownTimer?.cancel();
    _countdownTimer = null;
  }

  @override
  void dispose() {
    _stopCountdown();
    _connSub?.cancel();
    _connSub = null;
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final isOnline = _stompService.isConnected && _stompService.isAuthenticated;
    if (isOnline) return const SizedBox.shrink();

    // Different messages for initial connection vs connection lost
    final String title;
    final String subtitle;
    final IconData icon;
    final Color? bgColor;
    final Color? iconColor;
    final Color? titleColor;
    final Color? subtitleColor;

    if (_hadConnection) {
      // Connection was lost
      title = 'Offline – Verbindung verloren';
      subtitle = 'Verbindung wird wiederhergestellt.';
      icon = Icons.wifi_off;
      bgColor = Colors.red[50];
      iconColor = Colors.red[700];
      titleColor = Colors.red[900];
      subtitleColor = Colors.red[800];
    } else {
      // Initial connection attempt
      title = 'Verbinde mit Server...';
      subtitle = 'Bitte warten.';
      icon = Icons.sync;
      bgColor = Colors.orange[50];
      iconColor = Colors.orange[700];
      titleColor = Colors.orange[900];
      subtitleColor = Colors.orange[800];
    }

    return Container(
      width: double.infinity,
      padding: const EdgeInsets.symmetric(vertical: 10, horizontal: 12),
      color: bgColor,
      child: Row(
        children: [
          Icon(icon, color: iconColor),
          const SizedBox(width: 8),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              mainAxisSize: MainAxisSize.min,
              children: [
                Text(
                  title,
                  style: TextStyle(
                    color: titleColor,
                    fontWeight: FontWeight.w700,
                  ),
                ),
                const SizedBox(height: 2),
                Text(
                  subtitle,
                  style: TextStyle(
                    color: subtitleColor,
                    fontSize: 12,
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}