three functions (press, double-click, long press) in one button

[Jerson]

Well, I guess, you need to wait anyway to determine a double press. So, one option left is to reduce the waiting time from 1sec to maybe 300mS.

Second option would be to selectively look for a single press, double press or long press where applicable and thus save the common routine which determines all three modes.

[Mike, K8LH]

I think "short" press, "long" press (>1 second), and "longer" press (>2 seconds) might work better since you can act on the "release" switch state. I would also use a piezo speaker or something similar for audible feedback. Generate a single short beep on the "new press" state, a double beep at the one second timeout, and a triple beep at the 2 second timeout.

Cheerful regards, Mike