import 'dart:async';
import 'dart:convert';

import 'package:flutter/foundation.dart';
import 'package:http/http.dart' as http;

import '../database/app_database.dart';
import '../models/remote_command.dart';
import '../services/remote_sync_service.dart';
import '../utils/app_config.dart';

class RemoteSyncViewModel extends ChangeNotifier {
  final RemoteSyncService syncService;

  RemoteSyncViewModel({required this.syncService}) {
    _eventSubscription = syncService.events.listen(_onEvent);
  }

  StreamSubscription<RemoteSyncEvent>? _eventSubscription;

  List<RemoteSyncEvent> _recentEvents = [];

  List<RemoteSyncEvent> get recentEvents => _recentEvents;

  bool _isSyncing = false;
  bool get isSyncing => _isSyncing;

  bool _isConfigured = false;
  bool get isConfigured => _isConfigured;

  DateTime? _lastSyncAt;
  DateTime? get lastSyncAt => _lastSyncAt;

  String? _lastError;
  String? get lastError => _lastError;

  String? _venueId;
  String? get venueId => _venueId;

  List<ProcessedRemoteCommandRow> _activity = [];
  List<ProcessedRemoteCommandRow> get activity => _activity;

  bool _isRegistering = false;
  bool get isRegistering => _isRegistering;

  String? _registrationError;
  String? get registrationError => _registrationError;

  Future<void> init() async {
    _isConfigured = await syncService.isConfigured;
    _venueId = await syncService.venueId;
    _lastSyncAt = await syncService.lastSuccessfulSyncAt;
    await loadActivity();
    if (_isConfigured) {
      syncService.startPeriodicSync();
    }
    notifyListeners();
  }

  Future<void> refreshStatus() async {
    _isConfigured = await syncService.isConfigured;
    _venueId = await syncService.venueId;
    notifyListeners();
  }

  Future<void> syncNow() async {
    _isSyncing = true;
    _lastError = null;
    notifyListeners();

    await syncService.sync();

    _isSyncing = syncService.isSyncing;
    _lastSyncAt = await syncService.lastSuccessfulSyncAt;
    await loadActivity();
    notifyListeners();
  }

  Future<void> loadActivity() async {
    try {
      _activity = await syncService.getRecentActivity();
    } catch (e) {
      debugPrint('RemoteSyncViewModel: loadActivity error: $e');
    }
  }

  Future<bool> registerDevice({
    required String venueId,
    required String deviceName,
    required String registrationCode,
  }) async {
    _isRegistering = true;
    _registrationError = null;
    notifyListeners();

    try {
      final response = await http.post(
        Uri.parse('$kRemoteServerUrl/devices/register'),
        headers: {'Content-Type': 'application/json'},
        body: jsonEncode({
          'venueId': venueId,
          'name': deviceName,
          'registrationCode': registrationCode,
        }),
      ).timeout(const Duration(seconds: 15));

      if (response.statusCode == 201) {
        final data = jsonDecode(response.body) as Map<String, dynamic>;
        final deviceId = data['deviceId'] as String;
        final token = data['token'] as String;

        await syncService.setCredentials(
          deviceId: deviceId,
          token: token,
          venueId: venueId,
          serverUrl: kRemoteServerUrl,
        );

        _isConfigured = true;
        _venueId = venueId;
        _isRegistering = false;
        notifyListeners();

        syncService.startPeriodicSync();
        await syncNow();

        return true;
      } else {
        final body = response.body;
        String message;
        try {
          final errorData = jsonDecode(body) as Map<String, dynamic>;
          message = errorData['message'] as String? ?? 'Registration failed';
        } catch (_) {
          message = 'Registration failed (HTTP ${response.statusCode})';
        }
        _registrationError = message;
        _isRegistering = false;
        notifyListeners();
        return false;
      }
    } catch (e) {
      debugPrint('RemoteSyncViewModel: registration error: $e');
      _registrationError = e.toString();
      _isRegistering = false;
      notifyListeners();
      return false;
    }
  }

  Future<void> unlink() async {
    syncService.stopPeriodicSync();
    await syncService.clearCredentials();
    _isConfigured = false;
    _venueId = null;
    _lastSyncAt = null;
    _lastError = null;
    _recentEvents = [];
    _activity = [];
    notifyListeners();
  }

  void startSync() {
    syncService.startPeriodicSync();
    syncNow();
  }

  void _onEvent(RemoteSyncEvent event) {
    _recentEvents = [event, ..._recentEvents.take(49)];
    _lastSyncAt = DateTime.now();

    if (event.type == RemoteSyncEventType.syncFailed) {
      _lastError = event.message;
    } else if (event.type == RemoteSyncEventType.syncCompleted) {
      _lastError = null;
    }

    notifyListeners();
  }

  void pause() {
    syncService.pause();
  }

  void resume() {
    syncService.resume();
    syncNow();
  }

  @override
  void dispose() {
    _eventSubscription?.cancel();
    syncService.dispose();
    super.dispose();
  }
}