push notification C#

We want developer C# how have experience in FCM and APNS to implement the needed function in one library in our project and to provide simple interface functions to othere developer to use it in implementation The interface should be simple like publish Course (Course ID) publish event (Event ID) Publish Event (EventID, SQL Condition to select users .. ) Something like this interface It should be clear and documented And it should use FCM for android and APNS for iOS all things related to the notifications storing the notification table delete from it clearing it all things related to notifications , storing the notifications for all users depending on the condition insert all where condition ….. also Web notifications the clients will be android, Ios, web