How to automate sending out discount coupon if user has shared a post on social media?

Hey

Not sure it is possible, so I ask this great community :)

We want to give 50% discount to our customers whom have shared info about it in social media- Friends of friends who also share should get 50%

I know I can ask customers to send me proof (screenshot) they have shared among their friends on social media, and then I send them an email back containing the discount coupon…

But can't this be automated? Like if they share it and they automatically get the coupon…. wonder so I…

How to automate sending out discount coupon if user has shared a post on social media?