How does one go about making a complex mod for Minecraft?

Well, me and my friends love playing Strategy, citybuilder, and RTS games. We also love playing Tekkit. I'm beginning to get into learning Python as my first code language, and I had the most amazing idea: an evony inspired mod for minecraft! Unfortunately, I'm unsure if my limited knowledge of Python will help me with a mod for a Javascript based game like minecraft, and I'm not in the mood to learn Javascript and Python at the same time.

So, my question is, simply, how do you do it?

I'm hoping that a program exists that assists with mod-writing (like an Adobe Dreamweaver sort of thing but for writing minecraft mods) but if that isn't a thing, then where could I learn how to create mods for minecraft?

It sounds like a really interesting project for the summer and any information you guys can provide would be greatly appreciated!

I highly recommend just learning JavaScript and then another language of your choice. Python is amazing but won't help you that much when coding in Java. You don't need special software to code in unlike other coding languages, all you need is a simple word program of your choice for example notepad. It can be executed as scripts and jar files. As JavaScript is so simple the software needed is minimal.