How to use Class Reference Classes within the Craft framework for plugin development
You may already be aware of this, but the Class Reference is a complete breakdown of the Craft core. Everything that exists within the craft/app folder is documented here.

Craft is built upon the Yii framework. If you dig deep enough, many roads lead back to Yii queries. Fortunately, you'll rarely have to dig that deep! Craft has abstracted away much of the raw Yii commands into all of its Base classes.

Continuing from there, pretty much everything else that happens in Craft is layered upon the Base classes. You'll notice that most of the common components (Services, Controllers, Records, etc) contain a Base class, and all other classes are extended from there. In general, you can think of the Craft core as being "one big plugin"... In fact, when Craft 3 is released, this will be even more true.

It's important to note that your plugin won't need all of these components. Many plugins require only a few of these components to meet their needs. In your case, you may only need a Service, a Controller, a Record, a Model, and a Variable.



Beyond that, I'll skip any recommendations for your specific plugin project. My intention was only to respond to the general purpose of your question... I'd highly recommend opening a separate question with specific points about what you are setting out to accomplish.