Will this work with JMAP as well?

Yes, anything we add for IMAP, we should check JMAP support as well. Overall, it is built on top of IMAP, so it should work but please check if the new Scheduled folder is OK for JMAP.

Overall, the code is good but I have one concern - it only sends out while you are actively using Cypht and it seems to warn of unsent/scheduled messages each time you leave a page (onbeforeunload). That would be annoying for the end user. I believe this comment #576 (comment) proposes using sendAt support from jmap servers or scheduled send - if it is supported, we use it, if not, we fallback to a more annoying option. At any rate, it should be configurable.

This could be fully-supported in the Cypht-Tiki integration where there could be a Tiki command run periodically in the scheduler that checks and sends scheduled messages.

@kroky I added a commit to fix issue concerning onbeforeunload event and also add the option to change schedule time or send the message immediately. Can you check please.

@amaninyumu1 If you need help with JMAP, please reach out to @Shadow243 as he set up a JMAP server for testing.

@amaninyumu1 "This branch has conflicts that must be resolved"

@amaninyumu1 This branch has conflicts that must be resolved

Hello @marclaporte , @kroky I resolved the conflicts. please review

There are still conflicts and I believe big part of the reason is #1266 - @jacob-js , can you check if some handlers in this PR need to be updated according to the router changes you did in 1266?

$mailbox = new Hm_Mailbox($server_id, $user_config, $session, $config); for this new way of initializing Mailbox triggers unexpected errors like:
$mailbox->connect() : Uncaught Error: Call to a member function connect() on null while the $mailbox variable and the connection are not null after inspection
$mailbox->send_message($from[0]['email'], $recipients, $msg_content, $delivery_receipt); : PHP Fatal error: Uncaught Error: Call to undefined method Hm_IMAP::send_message(). Is there a new way to send messages with Hm_Mailbox. thanks
@kroky or @mercihabam can have an opinion here.

@amaninyumu1 you cannot use send_message method on an IMAP account - what would it mean? Mailbox on top of SMTP or EWS can send out emails and send_message is OK there but not on an IMAP account. For IMAP, there is store_message which stores a message in a specific folder. Please check your calling code.

@kroky the message is already stored in the scheduled folder I would like to implement the send now functionality for scheduled messages I use IMAP account

You can't send through an IMAP account. Use its corresponding SMTP or EWS account stored in a profile or use the default SMTP account. Show error if there is no configured account to send from.

@kroky I think this method is better for sending a message $mailbox = Hm_SMTP_List::connect($profile['smtp_id'], false); as with IMAP account you cannot send a message directly. thanks