Scheduled sending of an email (cron-like functionality)

[dumblob]

Motivation

E-mail services evolved over time and for practical business people tell me they expect an email service offering scheduled sending (to get "higher" in Monday's unread emails; to send marketing stuff prepared earlier; to not disturb your better half, etc.).

Envisioned solution

1. part: Email composure shall have a "split send button" - the second half being more or advanced opening a simple "panel" with few buttons and a date & time chooser. Buttons could be predefined prefill options: deschedule (cancelling any scheduling immediately - i.e. not first after "save" or whatever "form confirmation") 5 minutes later 1 hour later 24 hours later.

   The panel could be collapsing/uncollapsing in the page - the good old tags <details> & <summary> would be my first go-to option 😉 (or in worst case a modal which I dislike due to poor user friendliness especially on mobile devices and other usability issues etc.).

2. part: A GUI interface for editing & cancelling already scheduled emails. Maybe just tagging the given emails in the drafts folder listing (and when opened for editing, then auto-expand the more panel using <details open>...</details> and greying-out the default send button until a user chooses deschedule as described above).

Remarks

What to do with the schedule itself in case the user opens a scheduled email from the drafts folder and press send (i.e. sends it immediately). One option is to make "normal send" and "scheduled send" mutually exclusive (this must be also reflected in the UI by greying out the buttons etc.) in which case we wouldn't need to implement anything special - the used would need to first press deschedule in the extended menu and then finally she would be allowed to press send.

Then there is of course another option - to let the user send the scheduled draft without cancelling schedule (i.e. not mutually exclusive) and thus the email would be sent out immediately but at the same time remained in the drafts folder until the scheduled interval fires.

This is a tough thing to decide IMHO - in the end I tend to slightly prefer the former as it sound a bit simpler (the principle of least surprise for the user).

Related: #572 (also requires cron-like backend)

[dumblob]

Closing in favor of #576 (which I did not find in the tracker for some reason).