Custom Keyboard like Gboard for Android

Question

I'm looking for references to do a keyboard app like Gboard. I checked GitHub and googled for custom keyboard for android code and I still don't know what to do.

I came across AnySoftKeyboard but it seems complicated and I think it's not what I'm looking for.

I don't need the keyboard to be that customised, I want to have a search functionality when a user clicked on a key from the keyboard, it will show an input field where the user can type any text and automatically search on the internet about the typedText and display the searches then user can share it as part of the text he/she will send to the recipient.