Implement UI/UX and backend in terms of SRP

[timGalk]

The majority of functions contain the complex logic that makes impossible to develop new features

[xhoneybear]

Please specify what exactly. I have no issues with creating new features, it's a matter of rearranging the code every now and then to accommodate to the changes. It facilitates good design by itself. But we can work on that if you provide more details.