import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:test_sa/controllers/api_routes/api_manager.dart';
import 'package:test_sa/controllers/api_routes/urls.dart';
import 'package:test_sa/modules/notification_setting/models/notification_preference_model.dart';

class NotificationSettingProvider extends ChangeNotifier {
  // State management
  bool _isLoading = false;
  bool _isLoadingMore = false;
  bool _isSaving = false;
  String? _errorMessage;
  List<NotificationTemplate> _templates = [];

  // Pagination
  int _currentPage = 1;
  final int _pageSize = 10;
  int _totalRecords = 0;
  bool _hasMoreData = true;

  // Getters
  bool get isLoading => _isLoading;
  bool get isLoadingMore => _isLoadingMore;
  bool get isSaving => _isSaving;
  String? get errorMessage => _errorMessage;
  List<NotificationTemplate> get templates => _templates;
  bool get hasMoreData => _hasMoreData;
  bool get isEmpty => _templates.isEmpty && !_isLoading;

  // Check if there are any modified templates
  bool get hasChanges => _templates.any((template) => template.isModified);

  /// Load initial notification preferences
  Future<void> loadNotificationPreferences({bool refresh = false}) async {
    if (refresh) {
      reset();
    }

    if (_isLoading || _isLoadingMore) return;

    _isLoading = _currentPage == 1;
    _errorMessage = null;
    notifyListeners();

    try {
      final body = {
        'pageNumber': _currentPage,
        'pageSize': _pageSize,
      };

      http.Response response = await ApiManager.instance.post(
        URLs.getNotificationPreferences,
        body: body,
        showToast: false,
      );

      if (response.statusCode >= 200 && response.statusCode < 300) {
        final jsonData = json.decode(response.body);
        final notificationResponse = NotificationPreferenceResponse.fromJson(jsonData);

        if (notificationResponse.isSuccess == true && notificationResponse.data != null) {
          _totalRecords = notificationResponse.totalRows ?? 0;

          if (notificationResponse.data!.isNotEmpty) {
            _templates.addAll(notificationResponse.data!);
            _currentPage++;
            _hasMoreData = _templates.length < _totalRecords;
          } else {
            _hasMoreData = false;
          }
        } else {
          _errorMessage = notificationResponse.message ?? 'Failed to load notification preferences';
          _hasMoreData = false;
        }
      } else {
        _errorMessage = 'Failed to load notification preferences';
        _hasMoreData = false;
      }
    } catch (error) {
      _errorMessage = 'An error occurred while loading data';
      print('Error in loadNotificationPreferences: $error');
    } finally {
      _isLoading = false;
      notifyListeners();
    }
  }

  /// Load more data for pagination
  Future<void> loadMoreData() async {
    if (_isLoadingMore || !_hasMoreData || _isLoading) return;

    _isLoadingMore = true;
    notifyListeners();

    try {
      final body = {
        'pageNumber': _currentPage,
        'pageSize': _pageSize,
      };

      http.Response response = await ApiManager.instance.post(
        URLs.getNotificationPreferences,
        body: body,
        showToast: false,
      );

      if (response.statusCode >= 200 && response.statusCode < 300) {
        final jsonData = json.decode(response.body);
        final notificationResponse = NotificationPreferenceResponse.fromJson(jsonData);

        if (notificationResponse.isSuccess == true && notificationResponse.data != null) {
          if (notificationResponse.data!.isNotEmpty) {
            _templates.addAll(notificationResponse.data!);
            _currentPage++;
            _hasMoreData = _templates.length < _totalRecords;
          } else {
            _hasMoreData = false;
          }
        } else {
          _hasMoreData = false;
        }
      } else {
        _hasMoreData = false;
      }
    } catch (error) {
      print('Error in loadMoreData: $error');
    } finally {
      _isLoadingMore = false;
      notifyListeners();
    }
  }

  /// Update enable/disable state for a template
  void updateTemplateState(int index, bool isDisabled) {
    if (index < 0 || index >= _templates.length) {
      return;
    }

    final template = _templates[index];

    // Note: mandatory flag only applies to channel preferences, not to enable/disable toggle
    // Users can always enable/disable notifications

    _templates[index] = template.copyWith(
      isDisabled: isDisabled,
      isModified: true,
    );
    notifyListeners();
  }

  /// Update selected channels for a template
  void updateTemplateChannels(int index, List<int> channelIds) {
    if (index < 0 || index >= _templates.length) return;

    final template = _templates[index];

    _templates[index] = template.copyWith(
      selectedChannelIds: channelIds,
      isModified: true,
    );
    _templates[index].selectedChannelIds = channelIds;
    notifyListeners();
  }

  /// Save all modified preferences
  Future<bool> savePreferences() async {
    if (!hasChanges) return true;

    _isSaving = true;
    _errorMessage = null;
    notifyListeners();

    try {
      final preferences = _templates.where((t) => t.isModified).map((template) {
        return {
          'notificationTemplateId': template.notificationTemplateId,
          'disabled': template.isDisabled ?? false,
          'channels': template.selectedChannelIds,
        };
      }).toList();

      if (preferences.isEmpty) {
        _isSaving = false;
        notifyListeners();
        return true;
      }

      // Use ApiManager's postList method for array body
      http.Response response = await ApiManager.instance.postList(
        URLs.saveNotificationPreferences,
        body: preferences,
        showToast: true,
      );

      if (response.statusCode >= 200 && response.statusCode < 300) {
        // Reset modification flags after successful save
        for (var i = 0; i < _templates.length; i++) {
          _templates[i] = _templates[i].copyWith(isModified: false);
        }

        _isSaving = false;
        notifyListeners();
        return true;
      } else {
        _errorMessage = 'Failed to save preferences';
        _isSaving = false;
        notifyListeners();
        return false;
      }
    } catch (error) {
      _errorMessage = 'An error occurred while saving';
      _isSaving = false;
      notifyListeners();
      print('Error in savePreferences: $error');
      return false;
    }
  }

  /// Reset provider state
  void reset() {
    _templates.clear();
    _currentPage = 1;
    _hasMoreData = true;
    _totalRecords = 0;
    _isLoading = false;
    _isLoadingMore = false;
    _errorMessage = null;
  }

  /// Retry loading after error
  Future<void> retry() async {
    reset();
    await loadNotificationPreferences();
  }
}