I have a problem that i don't really know how to solve.
Background:
I'm developing a exercise app with Xamarin (native, Xamarin.Android & Xamarin.iOS).
The user will have to schedule when they are suppose to exercise, for example 2 pm every Thursday. The user gets an local local notification at 2 pm, that says "Hey - exercise". Afterwards the user are supposed to register the training session in the training log (Fitness journal, don't know the correct word).
I have all of that implemented but here is
The problem
Every night (8 pm) a user has planned to work out, an local notification should fire if there is no entry in the diary. The notification is suppose to say "No entry in the log."
I can see two ways how to solve this, but I wanna hear if you have any suggestions.
My customer don't have a lot of money, so a time-efficient solution is preferable.
1. possible solution
When a user schedule his/hers training set two alarms. One at 2 pm (that says "Hey exercise"), and another at 8 pm (that says "No entry in the log").
When a user add a entry in the log, find and dismiss the 8 pm notification.
2. possible solution
Try to wake the app at 8 pm every night and check if today was scheduled and if there are any entry in the training log. If scheduled but no entry -> fire local notification. Otherwise do nothing.
The problem with this solution is that I don't know how to wake the app at a specific time, from the background. I've not implemented remote push-notifications, so a silent remote push notification is not possible I think (with the customers budget).
I've tried with "background fetch", but no success there and I've read it's unreliable.
So any thoughts?
Am I missing anything obvious?
I really appreciate your thoughts!
Thanks 