Custom Application for mac OS

We need a program that is able to do, auto clicking, auto mouse cursor movements, and auto typing. I am trying to make an application that is able to message people in my "iMessage" application, automatically. I have thousands of open conversation that I would need to be e, there is only one general message I would need to send to these people. I am just unable to manually do it and I need a program that can do it automatically.