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import 'dart:io';
import 'dart:convert';
import 'package:http/http.dart' as http;
import 'package:flutter/material.dart';
import 'package:device_info/device_info.dart';
import 'package:flutter/services.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:study_app/models/user.dart';
import 'constants.dart' as Constants;

class LoginProvider extends ChangeNotifier {
  bool _isLoading = true;
  bool get isLoading => _isLoading;

  Map<String, dynamic> _deviceDetails = {};
  Map<String, dynamic> get deviceDetails => _deviceDetails;

  User _user = User();
  User get user => _user;

  Future<void> login() async {
    _checkIsUserLoggedIn();

    if (_deviceDetails.isEmpty) {
      print("[INFO] NEW USER DEVICE DETECTED");
      print("[INFO] LOGGING IN...");
      _getDeviceDetails();
      try {
        if (_deviceDetails.isNotEmpty) {
          // post request to server
          print(_deviceDetails);
          Map<String, String> requestBody = {
            'device_id': _deviceDetails['deviceID']!
          };

          http.Response response = await http
              .post(Uri.parse(Constants.LOGIN_ENDPOINT), body: requestBody);
          _user = userFromJson(response.body);
          _deviceDetails['userID'] = _user.data!.userId!;
          _deviceDetails['userName'] = _user.data!.name!;
          _deviceDetails['token'] = _user.data!.token!;
          _saveLoginDetails(_deviceDetails);
          print("[INFO] USER LOGGED IN SUCCESSFULLY");
        }
      } catch (error) {
        print("[INFO] ERROR WHILE FETCHING DEVICE DETAILS: $error");
      }
    } else {
      print("[INFO] THIS USER DEVICE IS ALREADY LOGGED IN");
      print("[INFO] FETCHING EXISTING USER DETAILS");
      // fetch _user again from post api.
      Map<String, dynamic> requestBody = {
        'device_id': _deviceDetails['deviceID']!
      };

      http.Response response = await http
          .post(Uri.parse(Constants.LOGIN_ENDPOINT), body: requestBody);
      _user = userFromJson(response.body);
    }
    _isLoading = false;
    notifyListeners();
  }

  Future<void> _getDeviceDetails() async {
    final DeviceInfoPlugin deviceInfoPlugin = DeviceInfoPlugin();
    try {
      if (Platform.isAndroid) {
        AndroidDeviceInfo deviceInfo = await deviceInfoPlugin.androidInfo;
        _deviceDetails['deviceName'] = deviceInfo.model;
        _deviceDetails['deviceVersion'] = deviceInfo.version.toString();
        _deviceDetails['deviceID'] = deviceInfo.androidId;
      } else if (Platform.isIOS) {
        IosDeviceInfo deviceInfo = await deviceInfoPlugin.iosInfo;
        _deviceDetails['deviceName'] = deviceInfo.name;
        _deviceDetails['deviceVersion'] = deviceInfo.systemVersion;
        _deviceDetails['deviceID'] = deviceInfo.identifierForVendor;
      }
    } on PlatformException {
      print("[INFO] Cannot get Device Information");
    }
    notifyListeners();
  }

  Future<void> _saveLoginDetails(Map<String, dynamic> deviceID) async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    prefs.setString(Constants.LOGGED_IN_USER, json.encode(deviceID));
  }

  Future<void> _checkIsUserLoggedIn() async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    _deviceDetails = json.decode(prefs.getString(Constants.LOGGED_IN_USER)!)
        as Map<String, dynamic>;
    notifyListeners();
  }
}