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

spec/mailers/conversation_reply_mailer_spec.rb

@@ -154,6 +154,32 @@ RSpec.describe ConversationReplyMailer, type: :mailer do
       end
     end
 
+    context 'when smtp enabled for email channel' do
+      let(:smtp_email_channel) do
+        create(:channel_email, smtp_enabled: true, smtp_address: 'smtp.gmail.com', smtp_port: 587, smtp_email: 'smtp@gmail.com',
+                               smtp_password: 'password', smtp_domain: 'smtp.gmail.com', account: account)
+      end
+      let(:conversation) { create(:conversation, assignee: agent, inbox: smtp_email_channel.inbox, account: account).reload }
+      let(:message) { create(:message, conversation: conversation, account: account, message_type: 'outgoing', content: 'Outgoing Message 2') }
+
+      it 'use smtp mail server' do
+        mail = described_class.email_reply(message)
+        expect(mail.delivery_method.settings.empty?).to be false
+        expect(mail.delivery_method.settings[:address]).to eq 'smtp.gmail.com'
+        expect(mail.delivery_method.settings[:port]).to eq 587
+      end
+    end
+
+    context 'when smtp disabled for email channel', :test do
+      let(:conversation) { create(:conversation, assignee: agent, inbox: email_channel.inbox, account: account).reload }
+      let(:message) { create(:message, conversation: conversation, account: account, message_type: 'outgoing', content: 'Outgoing Message 2') }
+
+      it 'use default mail server' do
+        mail = described_class.email_reply(message)
+        expect(mail.delivery_method.settings).to be_empty
+      end
+    end
+
     context 'when custom domain and email is not enabled' do
       let(:inbox) { create(:inbox, account: account) }
       let(:inbox_member) { create(:inbox_member, user: agent, inbox: inbox) }