elgg editor

Is there a tool / sotftware out there that support programming / customizing elgg?  I assume it would support PHP, but a little more customize to elgg.  since it has been a long time for me to do any kind of programming, i am very outdated.  the last thing i touched was Eclipse when I was programming java and customizing open source.  is there something like Eclipse, but specifically for elgg?  

thanks,