feat: IMAP Email Channel (#3298)

This change allows the user to configure both IMAP and SMTP for an email inbox. IMAP enables the user to see emails in Chatwoot. And user can use SMTP to reply to an email conversation.

Users can use the default settings to send and receive emails for email inboxes if both IMAP and SMTP are disabled.

Fixes #2520

app/mailers/conversation_reply_mailer.rb

@@ -1,4 +1,5 @@
 class ConversationReplyMailer < ApplicationMailer
+  include ConversationReplyMailerHelper
   default from: ENV.fetch('MAILER_SENDER_EMAIL', 'Chatwoot <accounts@chatwoot.com>')
   layout :choose_layout
 
@@ -12,16 +13,7 @@ class ConversationReplyMailer < ApplicationMailer
     new_messages = @conversation.messages.chat.where('id >= ?', last_queued_id)
     @messages = recap_messages + new_messages
     @messages = @messages.select(&:email_reply_summarizable?)
-    mail({
-           to: @contact&.email,
-           from: from_email_with_name,
-           reply_to: reply_email,
-           subject: mail_subject,
-           message_id: custom_message_id,
-           in_reply_to: in_reply_to_email,
-           cc: cc_bcc_emails[0],
-           bcc: cc_bcc_emails[1]
-         })
+    prepare_mail(true)
   end
 
   def reply_without_summary(conversation, last_queued_id)
@@ -34,14 +26,7 @@ class ConversationReplyMailer < ApplicationMailer
     @messages = @messages.reject { |m| m.template? && !m.input_csat? }
     return false if @messages.count.zero?
 
-    mail({
-           to: @contact&.email,
-           from: from_email_with_name,
-           reply_to: reply_email,
-           subject: mail_subject,
-           message_id: custom_message_id,
-           in_reply_to: in_reply_to_email
-         })
+    prepare_mail(false)
   end
 
   def email_reply(message)
@@ -49,17 +34,7 @@ class ConversationReplyMailer < ApplicationMailer
 
     init_conversation_attributes(message.conversation)
     @message = message
-
-    reply_mail_object = mail({
-                               to: @contact&.email,
-                               from: from_email_with_name,
-                               reply_to: reply_email,
-                               subject: mail_subject,
-                               message_id: custom_message_id,
-                               in_reply_to: in_reply_to_email,
-                               cc: cc_bcc_emails[0],
-                               bcc: cc_bcc_emails[1]
-                             })
+    reply_mail_object = prepare_mail(true)
 
     message.update(source_id: reply_mail_object.message_id)
   end
@@ -86,6 +61,7 @@ class ConversationReplyMailer < ApplicationMailer
     @contact = @conversation.contact
     @agent = @conversation.assignee
     @inbox = @conversation.inbox
+    @channel = @inbox.channel
   end
 
   def should_use_conversation_email_address?