New to round cube. Build list of contacts from current sent and rcvd email?

[berkeleydb]

I am new to roundcube and trying to help a local organization rebuild their contact list after a webmail host change went badly.   I'm doing this for a Mexican organization while on vacation down here.

Is there a way from roundcube or via local scriipt to scrape inbox and sent mail for the to or from email address ?
The alternative is to rebuild contacts by hand... but there are over 1000 so I'd prefer to find a way to let the software work for me.