Different types one form?

Question

Ruby on Rails

Help solve the problem...
There are 3 types of material
News, Article, Video
All three have essentially the same fields, but each has 3-4 different fields specific only to a certain type.
Since I have a type choice in Post, respectively, and there is only one form, but dumping all this into one form is crazy.
And there was a problem with validation. For example, I fill in the news type and I don’t need the test fields, it is needed for the Video type, and it is written in the validation that it is mandatory.
How to make it so that when choosing a type there would be only the necessary fields and validation of these particular fields?
Or as an option to divide it all into 3 different forms.
For example, create /news/add and make a type selection in the view, if the type is news, then we render the news form.
How to help me decide.

Answer 1

Don't make life difficult for yourself. Divide into different models, and common fields during rendering can be moved to partial.

Answer 2

It is better to spread the KMC into different classes and can be derived from the base class if necessary.