FEATURE: Use group SMTP job and mailer instead of UserNotifications change (#13489)

This PR backtracks a fair bit on this one https://github.com/discourse/discourse/pull/13220/files.

Instead of sending the group SMTP email for each user via `UserNotifications`, we are changing to send only one email with the existing `Jobs::GroupSmtpEmail` job and `GroupSmtpMailer`. We are changing this job and mailer along with `PostAlerter` to make the first topic allowed user the `to_address` for the email and any other `topic_allowed_users` to be the CC address on the email. This is to cut down on emails sent via SMTP, which is subject to daily limits from providers such as Gmail. We log these details in the `EmailLog` table now.

In addition to this, we have changed `PostAlerter` to no longer rely on incoming email email addresses for sending the `GroupSmtpEmail` job. This was unreliable as a user's email could have changed in the meantime. Also it was a little overcomplicated to use the incoming email records -- it is far simpler to reason about to just use topic allowed users.

This also adds a fix to include cc_addresses in the EmailLog.addressed_to_user scope.

spec/jobs/regular/group_smtp_email_spec.rb

@@ -4,63 +4,91 @@ require 'rails_helper'
 
 RSpec.describe Jobs::GroupSmtpEmail do
   fab!(:post) do
-    topic = Fabricate(:topic)
+    topic = Fabricate(:topic, title: "Help I need support")
     Fabricate(:post, topic: topic)
     Fabricate(:post, topic: topic)
   end
-  fab!(:group) { Fabricate(:imap_group) }
+  fab!(:group) { Fabricate(:smtp_group, name: "support-group", full_name: "Support Group") }
   fab!(:recipient_user) { Fabricate(:user, email: "test@test.com") }
   let(:post_id) { post.id }
   let(:args) do
     {
       group_id: group.id,
       post_id: post_id,
-      email: "test@test.com"
+      email: "test@test.com",
+      cc_emails: ["otherguy@test.com", "cormac@lit.com"]
     }
   end
 
   before do
-    SiteSetting.reply_by_email_address = "test+%{reply_key}@incoming.com"
-    SiteSetting.manual_polling_enabled = true
-    SiteSetting.reply_by_email_enabled = true
     SiteSetting.enable_smtp = true
+    SiteSetting.manual_polling_enabled = true
+    SiteSetting.reply_by_email_address = "test+%{reply_key}@test.com"
+    SiteSetting.reply_by_email_enabled = true
   end
 
   it "sends an email using the GroupSmtpMailer and Email::Sender" do
     message = Mail::Message.new(body: "hello", to: "myemail@example.invalid")
-    GroupSmtpMailer.expects(:send_mail).with(group, "test@test.com", post).returns(message)
-    Email::Sender.expects(:new).with(message, :group_smtp, recipient_user).returns(stub(send: nil))
+    GroupSmtpMailer.expects(:send_mail).with(group, "test@test.com", post, ["otherguy@test.com", "cormac@lit.com"]).returns(message)
     subject.execute(args)
   end
 
-  it "creates an IncomingEmail record to avoid double processing via IMAP" do
+  it "creates an EmailLog record with the correct details" do
     subject.execute(args)
-    incoming = IncomingEmail.find_by(post_id: post.id, user_id: post.user_id, topic_id: post.topic_id)
-    expect(incoming).not_to eq(nil)
-    expect(incoming.message_id).to eq("topic/#{post.topic_id}/#{post.id}@test.localhost")
-    expect(incoming.created_via).to eq(IncomingEmail.created_via_types[:group_smtp])
+    email_log = EmailLog.find_by(post_id: post.id, topic_id: post.topic_id, user_id: recipient_user.id)
+    expect(email_log).not_to eq(nil)
+    expect(email_log.message_id).to eq("topic/#{post.topic_id}/#{post.id}@test.localhost")
   end
 
-  it "creates a PostReplyKey and correctly uses it for the email reply_key substitution" do
+  it "creates an IncomingEmail record with the correct details to avoid double processing IMAP" do
     subject.execute(args)
-    incoming = IncomingEmail.find_by(post_id: post.id, user_id: post.user_id, topic_id: post.topic_id)
+    incoming_email = IncomingEmail.find_by(post_id: post.id, topic_id: post.topic_id, user_id: post.user.id)
+    expect(incoming_email).not_to eq(nil)
+    expect(incoming_email.message_id).to eq("topic/#{post.topic_id}/#{post.id}@test.localhost")
+    expect(incoming_email.created_via).to eq(IncomingEmail.created_via_types[:group_smtp])
+    expect(incoming_email.to_addresses).to eq("test@test.com")
+    expect(incoming_email.cc_addresses).to eq("otherguy@test.com;cormac@lit.com")
+    expect(incoming_email.subject).to eq("Re: Help I need support")
+  end
+
+  it "does not create a post reply key, it always replies to the group email_username" do
+    subject.execute(args)
+    email_log = EmailLog.find_by(post_id: post.id, topic_id: post.topic_id, user_id: recipient_user.id)
     post_reply_key = PostReplyKey.where(user_id: recipient_user, post_id: post.id).first
-    expect(post_reply_key).not_to eq(nil)
-    expect(incoming.raw).to include("Reply-To: Discourse <test+#{post_reply_key.reply_key}@incoming.com>")
+    expect(post_reply_key).to eq(nil)
+    expect(email_log.raw).not_to include("Reply-To: Support Group via Discourse <#{group.email_username}")
+    expect(email_log.raw).to include("From: Support Group via Discourse <#{group.email_username}")
   end
 
-  it "has the from_address and the to_addresses and subject filled in correctly" do
+  it "falls back to the group name if full name is blank" do
+    group.update(full_name: "")
     subject.execute(args)
-    incoming = IncomingEmail.find_by(post_id: post.id, user_id: post.user_id, topic_id: post.topic_id)
-    expect(incoming.to_addresses).to eq("test@test.com")
-    expect(incoming.subject).to include("Re: This is a test topic")
-    expect(incoming.from_address).to eq("discourseteam@ponyexpress.com")
+    email_log = EmailLog.find_by(post_id: post.id, topic_id: post.topic_id, user_id: recipient_user.id)
+    expect(email_log.raw).to include("From: support-group via Discourse <#{group.email_username}")
+  end
+
+  it "has the group_smtp_id and the to_address filled in correctly" do
+    subject.execute(args)
+    email_log = EmailLog.find_by(post_id: post.id, topic_id: post.topic_id, user_id: recipient_user.id)
+    expect(email_log.to_address).to eq("test@test.com")
+    expect(email_log.smtp_group_id).to eq(group.id)
+  end
+
+  context "when there are cc_addresses" do
+    let!(:cormac_user) { Fabricate(:user, email: "cormac@lit.com") }
+
+    it "has the cc_addresses and cc_user_ids filled in correctly" do
+      subject.execute(args)
+      email_log = EmailLog.find_by(post_id: post.id, topic_id: post.topic_id, user_id: recipient_user.id)
+      expect(email_log.cc_addresses).to eq("otherguy@test.com;cormac@lit.com")
+      expect(email_log.cc_user_ids).to eq([cormac_user.id])
+    end
   end
 
   context "when the post in the argument is the OP" do
     let(:post_id) { post.topic.posts.first.id }
     it "aborts and does not send a group SMTP email; the OP is the one that sent the email in the first place" do
-      expect { subject.execute(args) }.not_to(change { IncomingEmail.count })
+      expect { subject.execute(args) }.not_to(change { EmailLog.count })
     end
   end
 end