I would gladly host a class entitled "How to Craft a Shopify App" if enough developers wanted to make the effort to chug some beers and learn how to do it. I can spin them inside out, upside down, left-handed, embedded, purple, striped and polka-dotted... but none of that matters to the crowd that wants to be able to do that if I don't offer.
Glad I at least kicked you in the right direction... all the best!