Up front: I have JIRA Software 7.0.4 on-premises with ScriptRunner, Misc Custom Fields, and all the usual add-ons people will say this would be impossible without.
I'd like to be able to determine how much time has passed since an assignee has interacted with an issue. LastUpdated-by is one thing, and the difference between the issue's overall last updated date and today is another thing, but the important metric is how long it's taking for an assignee to respond to a ticket, even if a non-assignee is updating fields (delayed fixVersions) or adding comments ("Anybody home?").
The ultimate goal is to have something like an email alert be triggered for any issue where "assignee hasn't responded in 30+ days".
I'd like to avoid using transitions and special statuses when waiting for a response from someone, since that's workflow-specific and I'd really rather have something that can work system-wide.
Does anyone have ideas for how to achieve this kind of thing?