Container(
                              width: MediaQuery.sizeOf(context).width - 200,
                              height: 500,
                              padding: EdgeInsets.all(10),
                              decoration: BoxDecoration(
                                borderRadius: const BorderRadius.all(Radius.circular(20)),
                                boxShadow: [
                                  const BoxShadow(color: Colors.black54),
                                  BoxShadow(color: Colors.white, spreadRadius: -5, blurRadius: 5, offset: Offset.fromDirection(1, 5)),
                                ],
                              ),
                              child: c.SfCalendar(
                                initialDisplayDate: startday,
                                cellEndPadding: 0,
                                view: c.CalendarView.week,
                                firstDayOfWeek: DateTime.now().weekday,
                                onViewChanged: (dates) async {
                                  if (dates.visibleDates.first != startday) {
                                    startday = dates.visibleDates.first;
                                    await getdata();
                                  }
                                },
                                headerStyle: c.CalendarHeaderStyle(
                                  textAlign: TextAlign.center,
                                  backgroundColor: Colors.transparent,
                                  textStyle: const TextStyle(color: Colors.black87, fontWeight: FontWeight.bold),
                                ),
                                viewHeaderStyle: c.ViewHeaderStyle(
                                  dateTextStyle: const TextStyle(color: Colors.black87, fontWeight: FontWeight.bold),
                                  dayTextStyle: const TextStyle(color: Colors.black87, fontWeight: FontWeight.bold),
                                ),
                                blackoutDatesTextStyle: const TextStyle(color: Colors.black87, fontWeight: FontWeight.bold),
                                appointmentBuilder: (context, calendarAppointmentDetails) {
                                  return Container(
                                    alignment: Alignment.center,
                                    decoration: BoxDecoration(color: Colors.grey, borderRadius: const BorderRadius.all(Radius.circular(5))),
                                    child: Text(
                                      " ${calendarAppointmentDetails.appointments.first.name} ${DateFormat.Hm().format(calendarAppointmentDetails.appointments.first.from)}-${DateFormat.Hm().format(calendarAppointmentDetails.appointments.first.to)}",
                                      style: const TextStyle(color: Colors.black87, fontWeight: FontWeight.bold),
                                      textAlign: TextAlign.center,
                                    ),
                                  );
                                },
                                dataSource: ReservationDataSource(reservations),
                                timeSlotViewSettings: c.TimeSlotViewSettings(
                                  timeFormat: 'H:mm',
                                  timeIntervalHeight: 20,
                                  timeInterval: const Duration(minutes: 30),
                                  timeTextStyle: const TextStyle(fontSize: 11, color: Colors.black87, fontWeight: FontWeight.bold),
                                ),
                                onTap: (calendarTapDetails) {
                                  if (calendarTapDetails.appointments == null) {
                                    selectedreserve = -1;
                                    account = -1;
                                    dates.text = DateFormat.yMMMd().format(calendarTapDetails.date!);
                                    hours.text = DateFormat.Hm().format(calendarTapDetails.date!);
                                    datee.text = DateFormat.yMMMd().format(calendarTapDetails.date!.add(Duration(minutes: 30)));
                                    houre.text = DateFormat.Hm().format(calendarTapDetails.date!.add(Duration(minutes: 30)));

                                    setState(() {});
                                  } else {
                                    selectedreserve = calendarTapDetails.appointments?.first.id;
                                    account = calendarTapDetails.appointments?.first.acc;
                                    dates.text = DateFormat.yMMMd().format(calendarTapDetails.appointments?.first.from);
                                    hours.text = DateFormat.Hm().format(calendarTapDetails.appointments?.first.from);
                                    datee.text = DateFormat.yMMMd().format(calendarTapDetails.appointments?.first.to);
                                    houre.text = DateFormat.Hm().format(calendarTapDetails.appointments?.first.to);

                                    setState(() {});
                                  }
                                },
                              ),
                            ),

class ReservationDataSource extends c.CalendarDataSource {
  ReservationDataSource(List<Reservation> source) {
    appointments = source;
  }

  @override
  DateTime getStartTime(int index) {
    return appointments![index].from;
  }

  @override
  DateTime getEndTime(int index) {
    return appointments![index].to;
  }

  @override
  bool isAllDay(int index) {
    return appointments![index].isAllDay;
  }
}

class Reservation {
  Reservation(this.id, this.acc, this.name, this.from, this.to);

  var id;
  var acc;
  var name;
  var from;
  var to;
  bool isAllDay = false;
}

[Add the Stack Traces here]