feature: Separation of interface and impl

[konghaiya]

Is your feature request related to a problem? Please describe.

Separation of interface and impl.

Describe the solution you'd like

The interface needs to be separated from the concrete implementation. Interfaces are mainly declarations and definitions (in the form of pure virtual classes), Impl is a concrete implementation.

Describe alternatives you've considered

Additional context

[RingsC]

This also can be one of #11, because refactor the inferfaces of some classes can improve the code quality, and readability.