frequency of draft save timer to 5 seconds, ensure it runs when tapping back

[tomholub]

We shouldn't actually be encrypting the draft every second. We should only be encrypting a draft if the content changed from last second to the next.

And even then, we should probably change it to check once in 5 seconds, and one last time when we tap the back icon. I'll file a separate issue.

Originally posted by @tomholub in #970 (comment)

[ivan-ushakov]

Maybe we don't need to encrypt draft until we leave compose screen?

[tomholub]

That's not ideal - maybe internet is available in the beginning but not at the end - it would be better to have at least something saved. But if we ensure to save the draft when leaving the screen, then we can do a higher timer, say 5 seconds.

[ivan-ushakov]

Well, since we have local DB, this should not be a problem. We could always restore draft from DB

[tomholub]

You're suggesting offline functionality. Good suggestion - we'll eventually do that. At this moment though, I don't want to complicate the app with having more than one place to save (and read) drafts.

[ivan-ushakov]

You are right, looks like we encrypt draw only when message text is changed. So if I type 100 symbols, I will have 100 encrypt calls

[tomholub]

Hopefully not? If you typed it in 10 seconds, then you should have 2-3 encrypt calls max.

[ivan-ushakov]

We have draft check each second:

@objc private func startTimer() {
    saveDraftTimer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { [weak self] _ in
        self?.saveDraftIfNeeded()
    }
    saveDraftTimer?.fire()
}

Inside this check we just compare new and old messages (not only text, but also subject and recipients). So if I type new symbol each second, this check will return true and encrypt new message

[tomholub]

Yes, that's it currently. In this issue it will be changed to once in 5 seconds, and on more run on back tap.

But first, I'll probably disable all draft functionality and do a release. It's giving us too much trouble.

[ivan-ushakov]

OK, I was thinking about UI test fix, but if you need to have new release then let's disable draft