Generate auto-increment values in a composite primary key not first field in the innoDB table

The essence of the problem was that MyISAM tables have this ability and not for innoDB.

There is a table

messages
user_id INT
message_id INT

How to make so that when you insert into a table the values of the user_id, the value for message_id is generated
automatically?

Should be something like this

user_id	message_id
1	1
1	2
1	3
2	1
2	2
2	3

Made a trigger before insert which sets the value of the message_id as maximally id + 1,
everything works as it should, but after the insertion I do not know what message_id recorded the trigger.

The option of calculating the message_id and then insert (in two queries) is not suitable.