FIX: Improve participant display in group SMTP emails (#13539)

This PR makes several changes to the group SMTP email contents to make it look more like a support inbox message.

* Remove the context posts, they only add clutter to the email and replies
* Display email addresses of staged users instead of odd generated usernames
* Add a "please reply above this line" message to sent emails

spec/jobs/regular/group_smtp_email_spec.rb

@@ -3,10 +3,10 @@
 require 'rails_helper'
 
 RSpec.describe Jobs::GroupSmtpEmail do
+  fab!(:topic) { Fabricate(:private_message_topic, title: "Help I need support") }
   fab!(:post) do
-    topic = Fabricate(:topic, title: "Help I need support")
-    Fabricate(:post, topic: topic)
-    Fabricate(:post, topic: topic)
+    Fabricate(:post, topic: topic, raw: "some first post content")
+    Fabricate(:post, topic: topic, raw: "this is the second post reply")
   end
   fab!(:group) { Fabricate(:smtp_group, name: "support-group", full_name: "Support Group") }
   fab!(:recipient_user) { Fabricate(:user, email: "test@test.com") }
@@ -19,12 +19,19 @@ RSpec.describe Jobs::GroupSmtpEmail do
       cc_emails: ["otherguy@test.com", "cormac@lit.com"]
     }
   end
+  let(:staged1) { Fabricate(:staged, email: "otherguy@test.com") }
+  let(:staged2) { Fabricate(:staged, email: "cormac@lit.com") }
+  let(:normaluser) { Fabricate(:user, email: "justanormalguy@test.com", username: "normaluser") }
 
   before do
     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
+    TopicAllowedGroup.create(group: group, topic: topic)
+    TopicAllowedUser.create(user: staged1, topic: topic)
+    TopicAllowedUser.create(user: staged2, topic: topic)
+    TopicAllowedUser.create(user: normaluser, topic: topic)
   end
 
   it "sends an email using the GroupSmtpMailer and Email::Sender" do
@@ -33,6 +40,55 @@ RSpec.describe Jobs::GroupSmtpEmail do
     subject.execute(args)
   end
 
+  it "includes a 'reply above this line' message" 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.as_mail_message.html_part.to_s).to include(I18n.t("user_notifications.reply_above_line"))
+  end
+
+  it "does not include context posts" 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.as_mail_message.text_part.to_s).not_to include(I18n.t("user_notifications.previous_discussion"))
+    expect(email_log.as_mail_message.text_part.to_s).not_to include("some first post content")
+  end
+
+  it "includes the participants in the correct format" 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.as_mail_message.text_part.to_s).to include("Support Group")
+    expect(email_log.as_mail_message.text_part.to_s).to include("otherguy@test.com")
+    expect(email_log.as_mail_message.text_part.to_s).to include("cormac@lit.com")
+    expect(email_log.as_mail_message.text_part.to_s).to include("normaluser")
+  end
+
+  it "creates an EmailLog record with the correct details" 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).not_to eq(nil)
+    expect(email_log.message_id).to eq("topic/#{post.topic_id}/#{post.id}@test.localhost")
+  end
+
+  it "creates an IncomingEmail record with the correct details to avoid double processing IMAP" do
+    subject.execute(args)
+    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).to eq(nil)
+    expect(email_log.raw_headers).not_to include("Reply-To: Support Group via Discourse <#{group.email_username}")
+    expect(email_log.raw_headers).to include("From: Support Group via Discourse <#{group.email_username}")
+  end
+
   it "creates an EmailLog record with the correct details" do
     subject.execute(args)
     email_log = EmailLog.find_by(post_id: post.id, topic_id: post.topic_id, user_id: recipient_user.id)
@@ -64,7 +120,7 @@ RSpec.describe Jobs::GroupSmtpEmail do
     group.update(full_name: "")
     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.raw).to include("From: support-group via Discourse <#{group.email_username}")
+    expect(email_log.raw_headers).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
@@ -75,13 +131,11 @@ RSpec.describe Jobs::GroupSmtpEmail do
   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])
+      expect(email_log.cc_user_ids).to match_array([staged1.id, staged2.id])
     end
   end