Realistic mob eyesight

Hello everyone,

I was wondering if there is a plugin that makes it so mobs can only see you if they are looking directly at you or you are in a 5 block radius of them without shifting. If you shift and sneak up behind a mob you will be able to stealth kill (1 hit kill) it without it attracting other mobs but if you get spotted in the line of sight of a mob then it will attract mobs in a radius of 10 blocks.

Thank you for the help! I only really need the line of sight aspect

-pewax