2 Suggestions

[ZiadMohammed]

Maybe night vision is not important for some members but Flash bang is important like what san said everything is possible, watch the video.

[Tamer]

In every game that has night vision, I never use them.

I don't see flash bang here

Everything is possible in programming.
Here

I've also created this type of thingy for my server, long time

This video doesn't show the full story. A flashbang is a device that will make everyone looking towards it blind. What you see at the video is just a grenade with the blast effect (health loss effect) removed and replaced with a screen flashing effect. This won't function as a flash bang, A flashbang should give the blinding effect to all players facing the flashbang. The one at the video will work if you are close enough to the grenade and in range of the explosion.

Making a proper a flashbang at SA-MP is not impossible, however it is quite hard to do right now. Because there's no proper physics simulation at SA-MP (yet) there is a guy working on that, however It won't be complete anytime soon and by physics I mean bouncing off walls and actually detecting surface collisions. These hard to do right now at SA-MP since these calculations must be done server side.

So there won't be flashbangs as of yet and I find nightvision completely useless (plus it's buggy)