I have been working in this script until it generated a hello world that compiles into an apk. It is available in this gist:

gist.github.com/vokimon/38f1f6d2ce1b90bcb2676de2d51e520d

Hope it is useful, but consider I am an Android newbie, so for sure it can be improved a lot. Please, send me any updates you make to it.