Understanding and building a social network algorithm

I am not sure if this is the right platform to ask this question. But my problem is this: I have a bookstore and x have no customers (x is huge).

A client can tell me a good or bad book (not recommended). I have internal logic for collective books together, so if a client says that the book is bad, he says that such books are also bad and do not show it.

I oblige and hide these books. Clients can also interact with each other and have a mutual confidence level between them. A case arises when client A says that book X1 is bad. Therefore, the blacklist is X1, X2, X3, X4, etc.

But his client friend B says the X3 is good. So, now I need to show X3 to A. I thought to build a social network for all my clients based on their interaction and be able to calculate the level of mutual confidence. Therefore, in the above senario, if the level of mutual trust is very high, X3 to A will be displayed, otherwise I will not show X3 on A.

I wanted me to start social networking and assign wt. to the path between two nodes (my clients). Please offer me some good pointers where I can start. Any book, websites, etc.

thank