Does practicing masturbation during the day, with the assumption that it is nighttime, invalidate the fast?

The fast is broken by the emission of semen through masturbation, and you are required to make up that day, even if you were unaware of the entry of the fasting time. However, if semen was not emitted, then the fast is valid, and you are not required to make up the day. Nevertheless, you must repent from masturbation because it is a sin.