As of now,
1. The automation accepts a profile url, saves in database
2. Scans posts of that profile
3. Scans interacting people of those posts
4. Sends a defined DM to each interacting actors.
5. Periodically hourly basis, it scans DB record for the latest profile URL and do step 2 to step 5.
Caveats
Things that may appear as problem or are problems (not complex, just not implemented yet, need direction)
1. It sends a message for each interaction, a single person may have interacted in multiple posts, gets multiple message
2. It checks for all historical post for the given profiles
3. No message sent event is tracked, on the next periodical trigger, those who received message will receive again.