doctor_app_flutter/lib/util/date-utils.dart

import 'package:intl/intl.dart';

class DateUtils {

  static String convertStringToDateFormat(String date, String dateFormat) {
    DateTime dateTime = DateTime.parse(date);
    return DateFormat(dateFormat).format(dateTime);
  }

  static convertDateFromServerFormat(String str, dateFormat) {
    const start = "/Date(";

    const end = "+0300)";

    final startIndex = str.indexOf(start);

    final endIndex = str.indexOf(end, startIndex + start.length);

    var date = new DateTime.fromMillisecondsSinceEpoch(
        int.parse(str.substring(startIndex + start.length, endIndex)));

    return DateFormat(dateFormat).format(date);
  }

  static String differenceBetweenDateAndCurrentInYearMonthDay(DateTime firstDate) {
    DateTime now = DateTime.now();
    // now = now.add(Duration(days: 400, minutes: 0));
    var difference = firstDate.difference(now);

    int years = now.year - firstDate.year;
    int months = now.month - firstDate.month;
    int days = now.day - firstDate.day;

    if (months < 0 || (months == 0 && days < 0)) {
      years--;
      months += (days < 0 ? 11 : 12);
    }
    if (days < 0) {
      final monthAgo = new DateTime(now.year, now.month - 1, firstDate.day);
      days = now.difference(monthAgo).inDays + 1;
    }


    return "$days Days, $months Months, $years Years";
  }

  static String differenceBetweenDateAndCurrent(DateTime firstDate) {
    DateTime now = DateTime.now();
    // DateTime now = nows.add(Duration(days: 400, minutes: 25, hours: 0));
    var difference = now.difference(firstDate);

    int minutesInDays = difference.inMinutes;
    int hoursInDays = minutesInDays ~/ 60;
    int minutes = minutesInDays % 60;
    int days = hoursInDays ~/ 24;
    int hours = hoursInDays % 24;

    double hoursInOneDay = difference.inHours / difference.inDays;

    return "$days Days, $hours HR, $minutes Min";
  }

  static String differenceBetweenServerDateAndCurrent(String str) {
    const start = "/Date(";

    const end = "+0300)";

    final startIndex = str.indexOf(start);

    final endIndex = str.indexOf(end, startIndex + start.length);

    var date = new DateTime.fromMillisecondsSinceEpoch(
        int.parse(str.substring(startIndex + start.length, endIndex)));
    return differenceBetweenDateAndCurrent(date);
  }
}