What to do if there is no officially delivered API, and you really want to expand the capabilities of the application?

Question

API

It is required to write a host bot (analogous to ghost++ for Warcraft 3) that will be able to create games over the network and track statistics in them. There is no semblance of an API to help in this matter. How can you get out of this situation? In general, in relation not only to games, there is some kind of application - a program for Windows. I wanted to expand its capabilities, not to write a complete analogue with "its own additional functions". How can this be done and what are the techniques? Interested in absolutely any options, including the most labor-intensive. Thank you.

Answer 1

1) Reverse engineering to understand how the game code is used to create the game, Then:
2) Dll Injection to control the game process directly, or more reverse engineering to recreate the actions needed to create the game in your program.