Wrong fire date UILocalNotification - fire date is one hour ahead - ios

Question

I want to set a UILocalNotification to go off at a certain time. The app deals with restaurant bookings. If a booking is made and the appointment is greater than 2 hours from now, then I want to show the notification 2 hours before it. If it is greater than 1 hour then I was to show it 1 hour before hand, else I want to show it 15 mins before hand. The dificulty Im having is that my UILocalNotification fire time is wrong by + 1 hour. Below is the code used:
[self setLocalNotificationWithAlertBody:#"Alert Body goes here" AndWithBookingDateString:#"2015-09-07 19:45:00"];//the booking time
-(void)setLocalNotificationWithAlertBody:(NSString *)body AndWithBookingDateString:(NSString *)dateString{
NSLog(#"Date String %#",dateString);
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:#"GMT"]];
[dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:#"en_US_POSIX"]];
[dateFormatter setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
NSDate *dateFromString = [[NSDate alloc] init];
dateFromString = [dateFormatter dateFromString:dateString];
NSLog(#"Date from String %#",[dateFormatter dateFromString:dateString]);
[self setLocalNotificationWithAlertBody:body AndWithBookingDate:dateFromString];
}
-(void)setLocalNotificationWithAlertBody: (NSString *) body AndWithBookingDate: (NSDate *)date{
NSDate *currentDate = [NSDate date];
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSHourCalendarUnit
fromDate:currentDate
toDate:date
options:0];
UILocalNotification* localNotification = [[UILocalNotification alloc] init];
NSInteger hour = [components hour];
if (components.hour>=2) {//remind the user 2 hours before hand if booking is made greater than 2 hours
NSTimeInterval secondsPerHour = (60 * 60)*2;//two hours before appointment
NSDate *givenDate = date; // what you have already
NSDate *earlierDate = [givenDate dateByAddingTimeInterval:-secondsPerHour];
NSLog(#"\n\n Greater than 2 hours %# \n\n",earlierDate);
localNotification.fireDate=earlierDate;
localNotification.alertBody = [NSString stringWithFormat:#"%# %#",body,[self getDeviceShortDateFromString:[NSString stringWithFormat:#"%#",date] WithFormat:#"yyyy-MM-dd HH:mm:ss ZZZZZ"]];
}
else if (components.hour>1) {
NSTimeInterval secondsPerHour = 60 * 60;
NSDate *givenDate = date; // what you have already
NSDate *earlierDate = [givenDate dateByAddingTimeInterval:-secondsPerHour];
NSLog(#"\n\n Greater than an hour %# \n\n",earlierDate);
localNotification.fireDate=earlierDate;
localNotification.alertBody = [NSString stringWithFormat:#"%# %#",body,[self getDeviceShortDateFromString:[NSString stringWithFormat:#"%#",date] WithFormat:#"yyyy-MM-dd HH:mm:ss ZZZZZ"]];
}
else{
NSTimeInterval secondsPer15mins = 15 * 60;
NSDate *givenDate = date; // what you have already
NSDate *earlierDate = [givenDate dateByAddingTimeInterval:-secondsPer15mins];
NSLog(#"\n\n Less than one hour %# \n",earlierDate);
localNotification.fireDate=earlierDate;
localNotification.alertBody = [NSString stringWithFormat:#"%# %#",body,[self getDeviceShortDateFromString:[NSString stringWithFormat:#"%#",date] WithFormat:#"yyyy-MM-dd HH:mm:ss ZZZZZ"]];
}
localNotification.userInfo = #{#"key" : body};
[[UIApplication sharedApplication] scheduleLocalNotification:localNotification];
NSLog(#"Fire date %#",localNotification.fireDate);
NSLog(#"Notification--->: %#", localNotification);
}
-(NSString *)getDeviceShortDateFromString: (NSString *) date WithFormat: (NSString *)format{
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:#"en_US_POSIX"]];
[dateFormatter setDateFormat:format];
NSDate * tempDate =[dateFormatter dateFromString: date];
NSDateFormatter *dateFormatter2 = [[NSDateFormatter alloc] init];
[dateFormatter2 setDateFormat:#"MMM yyyy"];
if (tempDate == nil) {
return #" ";
}
return [dateFormatter2 stringFromDate:tempDate];
}
The fire date is logging as:
Fire date 2015-09-07 17:45:00 +0000
But the local notification is wrong:
Notification--->: <UIConcreteLocalNotification: 0x174178300>{fire date = Monday 7 September 2015 18:45:00 Irish Summer Time, time zone = (null), repeat interval = 0, repeat count = UILocalNotificationInfiniteRepeatCount, next fire date = Monday 7 September 2015 18:45:00 Irish Summer Time, user info = {
key = "Alert Body Goes here";
}}
The appointment was booked greater than 2 hours so the notification should be going off at 5:45 but it doesnt go off until 6:45. Any help is greatly appreciated.
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Answer 1

For scaleable apps that rely on location specific results, ensure that your location specific properties always point to the users relative location. In your case, you just overlooked a simple setting:
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:#"GMT"]];
For you, this is +1 hour, but for others it will vary some will be ahead and some will be behind, because your basing the fireDate on GMT's time.
I would simply alter this to be [NSTimeZone systemTimeZone]