discourse/spec/components/email/receiver_spec.rb

# frozen_string_literal: true

require "rails_helper"
require "email/receiver"

describe Email::Receiver do

  before do
    SiteSetting.email_in = true
    SiteSetting.reply_by_email_address = "reply+%{reply_key}@bar.com"
    SiteSetting.alternative_reply_by_email_addresses = "alt+%{reply_key}@bar.com"
  end

  def process(email_name)
    Email::Receiver.new(email(email_name)).process!
  end

  it "raises an EmptyEmailError when 'mail_string' is blank" do
    expect { Email::Receiver.new(nil) }.to raise_error(Email::Receiver::EmptyEmailError)
    expect { Email::Receiver.new("") }.to raise_error(Email::Receiver::EmptyEmailError)
  end

  it "raises a ScreenedEmailError when email address is screened" do
    ScreenedEmail.expects(:should_block?).with("screened@mail.com").returns(true)
    expect { process(:screened_email) }.to raise_error(Email::Receiver::ScreenedEmailError)
  end

  it "raises EmailNotAllowed when email address is not on allowlist" do
    SiteSetting.allowed_email_domains = "example.com|bar.com"
    Fabricate(:group, incoming_email: "some_group@bar.com")
    expect { process(:blocklist_allowlist_email) }.to raise_error(Email::Receiver::EmailNotAllowed)
  end

  it "raises EmailNotAllowed when email address is on blocklist" do
    SiteSetting.blocked_email_domains = "email.com|mail.com"
    Fabricate(:group, incoming_email: "some_group@bar.com")
    expect { process(:blocklist_allowlist_email) }.to raise_error(Email::Receiver::EmailNotAllowed)
  end

  it "raises an UserNotFoundError when staged users are disabled" do
    SiteSetting.enable_staged_users = false
    expect { process(:user_not_found) }.to raise_error(Email::Receiver::UserNotFoundError)
  end

  it "raises an AutoGeneratedEmailError when the mail is auto generated" do
    expect { process(:auto_generated_precedence) }.to raise_error(Email::Receiver::AutoGeneratedEmailError)
    expect { process(:auto_generated_header) }.to raise_error(Email::Receiver::AutoGeneratedEmailError)
  end

  it "raises a NoBodyDetectedError when the body is blank" do
    expect { process(:no_body) }.to raise_error(Email::Receiver::NoBodyDetectedError)
  end

  it "raises a NoSenderDetectedError when the From header is missing" do
    expect { process(:no_from) }.to raise_error(Email::Receiver::NoSenderDetectedError)
  end

  it "raises an InactiveUserError when the sender is inactive" do
    Fabricate(:user, email: "inactive@bar.com", active: false)
    expect { process(:inactive_sender) }.to raise_error(Email::Receiver::InactiveUserError)
  end

  it "raises a SilencedUserError when the sender has been silenced" do
    Fabricate(:user, email: "silenced@bar.com", silenced_till: 1.year.from_now)
    expect { process(:silenced_sender) }.to raise_error(Email::Receiver::SilencedUserError)
  end

  it "doesn't raise an InactiveUserError when the sender is staged" do
    user = Fabricate(:user, email: "staged@bar.com", active: false, staged: true)
    post = Fabricate(:post)

    post_reply_key = Fabricate(:post_reply_key,
      user: user,
      post: post,
      reply_key: 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'
    )

    expect { process(:staged_sender) }.not_to raise_error
  end

  it "raises a BadDestinationAddress when destinations aren't matching any of the incoming emails" do
    expect { process(:bad_destinations) }.to raise_error(Email::Receiver::BadDestinationAddress)
  end

  it "raises an OldDestinationError when notification is too old" do
    SiteSetting.disallow_reply_by_email_after_days = 2

    topic = Fabricate(:topic, id: 424242)
    post  = Fabricate(:post, topic: topic, id: 123456)
    user  = Fabricate(:user, email: "discourse@bar.com")

    expect { process(:old_destination) }.to raise_error(
      Email::Receiver::BadDestinationAddress
    )

    IncomingEmail.destroy_all
    post.update!(created_at: 3.days.ago)

    expect { process(:old_destination) }.to raise_error(
      Email::Receiver::OldDestinationError
    )

    SiteSetting.disallow_reply_by_email_after_days = 0
    IncomingEmail.destroy_all

    expect { process(:old_destination) }.to raise_error(
      Email::Receiver::BadDestinationAddress
    )
  end

  context "bounces" do
    it "raises a BouncerEmailError" do
      expect { process(:bounced_email) }.to raise_error(Email::Receiver::BouncedEmailError)
      expect(IncomingEmail.last.is_bounce).to eq(true)

      expect { process(:bounced_email_multiple_status_codes) }.to raise_error(Email::Receiver::BouncedEmailError)
      expect(IncomingEmail.last.is_bounce).to eq(true)
    end

    describe "creating whisper post in PMs for staged users" do
      let(:email_address) { "linux-admin@b-s-c.co.jp" }
      fab!(:user1) { Fabricate(:user) }
      let(:user2) { Fabricate(:staged, email: email_address) }
      let(:topic) { Fabricate(:topic, archetype: 'private_message', category_id: nil, user: user1, allowed_users: [user1, user2]) }
      let(:post) { create_post(topic: topic, user: user1) }

      before do
        SiteSetting.enable_staged_users = true
        SiteSetting.enable_whispers = true
      end

      def create_post_reply_key(value)
        Fabricate(:post_reply_key,
          reply_key: value,
          user: user2,
          post: post
        )
      end

      it "when bounce without verp" do
        create_post_reply_key("4f97315cc828096c9cb34c6f1a0d6fe8")

        expect { process(:bounced_email) }.to raise_error(Email::Receiver::BouncedEmailError)
        post = Post.last
        expect(post.whisper?).to eq(true)
        expect(post.raw).to eq(I18n.t("system_messages.email_bounced", email: email_address, raw: "Your email bounced").strip)
        expect(IncomingEmail.last.is_bounce).to eq(true)
      end

      it "when bounce with verp" do
        SiteSetting.reply_by_email_address = "foo+%{reply_key}@discourse.org"
        bounce_key = "14b08c855160d67f2e0c2f8ef36e251e"
        create_post_reply_key(bounce_key)
        Fabricate(:email_log, to_address: email_address, user: user2, bounce_key: bounce_key, post: post)

        expect { process(:hard_bounce_via_verp) }.to raise_error(Email::Receiver::BouncedEmailError)
        post = Post.last
        expect(post.whisper?).to eq(true)
        expect(post.raw).to eq(I18n.t("system_messages.email_bounced", email: email_address, raw: "Your email bounced").strip)
        expect(IncomingEmail.last.is_bounce).to eq(true)
      end
    end
  end

  it "logs a blank error" do
    Email::Receiver.any_instance.stubs(:process_internal).raises(RuntimeError, "")
    process(:existing_user) rescue RuntimeError
    expect(IncomingEmail.last.error).to eq("RuntimeError")
  end

  it "matches the correct user" do
    user = Fabricate(:user)
    email_log = Fabricate(:email_log, to_address: user.email, user: user, bounce_key: nil)
    email, name = Email::Receiver.new(email(:existing_user)).parse_from_field
    expect(email).to eq("existing@bar.com")
    expect(name).to eq("Foo Bar")
  end

  it "strips null bytes from the subject" do
    expect do
      process(:null_byte_in_subject)
    end.to raise_error(Email::Receiver::BadDestinationAddress)
  end

  context "bounces to VERP" do

    let(:bounce_key) { "14b08c855160d67f2e0c2f8ef36e251e" }
    let(:bounce_key_2) { "b542fb5a9bacda6d28cc061d18e4eb83" }
    fab!(:user) { Fabricate(:user, email: "linux-admin@b-s-c.co.jp") }
    let!(:email_log) { Fabricate(:email_log, to_address: user.email, user: user, bounce_key: bounce_key) }
    let!(:email_log_2) { Fabricate(:email_log, to_address: user.email, user: user, bounce_key: bounce_key_2) }

    it "deals with soft bounces" do
      expect { process(:soft_bounce_via_verp) }.to raise_error(Email::Receiver::BouncedEmailError)

      email_log.reload
      expect(email_log.bounced).to eq(true)
      expect(email_log.user.user_stat.bounce_score).to eq(SiteSetting.soft_bounce_score)
    end

    it "deals with hard bounces" do
      expect { process(:hard_bounce_via_verp) }.to raise_error(Email::Receiver::BouncedEmailError)

      email_log.reload
      expect(email_log.bounced).to eq(true)
      expect(email_log.user.user_stat.bounce_score).to eq(SiteSetting.hard_bounce_score)

      expect { process(:hard_bounce_via_verp_2) }.to raise_error(Email::Receiver::BouncedEmailError)

      email_log_2.reload
      expect(email_log_2.user.user_stat.bounce_score).to eq(SiteSetting.hard_bounce_score * 2)
      expect(email_log_2.bounced).to eq(true)
    end

    it "works when the final recipient is different" do
      expect { process(:verp_bounce_different_final_recipient) }.to raise_error(Email::Receiver::BouncedEmailError)

      email_log.reload
      expect(email_log.bounced).to eq(true)
      expect(email_log.user.user_stat.bounce_score).to eq(SiteSetting.soft_bounce_score)
    end

    it "sends a system message once they reach the 'bounce_score_threshold'" do
      expect(user.active).to eq(true)

      user.user_stat.bounce_score = SiteSetting.bounce_score_threshold - 1
      user.user_stat.save!

      SystemMessage.expects(:create_from_system_user).with(user, :email_revoked)

      expect { process(:hard_bounce_via_verp) }.to raise_error(Email::Receiver::BouncedEmailError)
    end
  end

  context "reply" do

    let(:reply_key) { "4f97315cc828096c9cb34c6f1a0d6fe8" }
    fab!(:category) { Fabricate(:category) }
    fab!(:user) { Fabricate(:user, email: "discourse@bar.com") }
    fab!(:topic) { create_topic(category: category, user: user) }
    fab!(:post) { create_post(topic: topic) }

    let!(:post_reply_key) do
      Fabricate(:post_reply_key,
        reply_key: reply_key,
        user: user,
        post: post
      )
    end

    let :topic_user do
      TopicUser.find_by(topic_id: topic.id, user_id: user.id)
    end

    it "uses MD5 of 'mail_string' there is no message_id" do
      mail_string = email(:missing_message_id)
      expect { Email::Receiver.new(mail_string).process! }.to change { IncomingEmail.count }
      expect(IncomingEmail.last.message_id).to eq(Digest::MD5.hexdigest(mail_string))
    end

    it "raises a ReplyUserNotMatchingError when the email address isn't matching the one we sent the notification to" do
      Fabricate(:user, email: "someone_else@bar.com")
      expect { process(:reply_user_not_matching) }.to raise_error(Email::Receiver::ReplyUserNotMatchingError)
    end

    it "raises a FromReplyByAddressError when the email is from the reply by email address" do
      expect { process(:from_reply_by_email_address) }.to raise_error(Email::Receiver::FromReplyByAddressError)
    end

    it "accepts reply from secondary email address" do
      Fabricate(:secondary_email, email: "someone_else@bar.com", user: user)

      expect { process(:reply_user_not_matching) }
        .to change { topic.posts.count }

      post = Post.last

      expect(post.raw).to eq(
        "Lorem ipsum dolor sit amet, consectetur adipiscing elit."
      )

      expect(post.user).to eq(user)
    end

    it "raises a ReplyNotAllowedError when user without permissions is replying" do
      Fabricate(:user, email: "bob@bar.com")
      category.set_permissions(admins: :full)
      category.save
      expect { process(:reply_user_not_matching_but_known) }.to raise_error(Email::Receiver::ReplyNotAllowedError)
    end

    it "raises a TopicNotFoundError when the topic was deleted" do
      topic.update_columns(deleted_at: 1.day.ago)
      expect { process(:reply_user_matching) }.to raise_error(Email::Receiver::TopicNotFoundError)
    end

    context "a closed topic" do

      before do
        topic.update_columns(closed: true)
      end

      it "raises a TopicClosedError when the topic was closed" do
        expect { process(:reply_user_matching) }.to raise_error(Email::Receiver::TopicClosedError)
      end

      it "Can watch topics via the watch command" do
        # TODO support other locales as well, the tricky thing is that these string live in
        # client.yml not on server yml so it is a bit tricky to find

        topic.update_columns(closed: true)
        process(:watch)
        expect(topic_user.notification_level).to eq(NotificationLevels.topic_levels[:watching])
      end

      it "Can mute topics via the mute command" do
        process(:mute)
        expect(topic_user.notification_level).to eq(NotificationLevels.topic_levels[:muted])
      end

      it "can track a topic via the track command" do
        process(:track)
        expect(topic_user.notification_level).to eq(NotificationLevels.topic_levels[:tracking])
      end
    end

    it "raises an InvalidPost when there was an error while creating the post" do
      expect { process(:too_small) }.to raise_error(Email::Receiver::TooShortPost)
    end

    it "raises an InvalidPost when there are too may mentions" do
      SiteSetting.max_mentions_per_post = 1
      Fabricate(:user, username: "user1")
      Fabricate(:user, username: "user2")
      expect { process(:too_many_mentions) }.to raise_error(Email::Receiver::InvalidPost)
    end

    it "raises an InvalidPostAction when they aren't allowed to like a post" do
      topic.update_columns(archived: true)
      expect { process(:like) }.to raise_error(Email::Receiver::InvalidPostAction)
    end

    it "works" do
      expect { process(:text_reply) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("This is a text reply :)\n\nEmail parsing should not break because of a UTF-8 character: ’")
      expect(topic.posts.last.via_email).to eq(true)
      expect(topic.posts.last.cooked).not_to match(/<br/)

      expect { process(:html_reply) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("This is a **HTML** reply ;)")
    end

    it "automatically elides gmail quotes" do
      SiteSetting.always_show_trimmed_content = true
      expect { process(:gmail_html_reply) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("This is a **GMAIL** reply ;)\n\n<details class='elided'>\n<summary title='Show trimmed content'>&#183;&#183;&#183;</summary>\n\nThis is the *elided* part!\n\n</details>")
    end

    it "doesn't process email with same message-id more than once" do
      expect do
        process(:text_reply)
        process(:text_reply)
      end.to change { topic.posts.count }.by(1)
    end

    it "handles different encodings correctly" do
      expect { process(:hebrew_reply) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("שלום! מה שלומך היום?")

      expect { process(:chinese_reply) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("您好！ 你今天好吗？")

      expect { process(:reply_with_weird_encoding) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("This is a reply with a weird encoding.")

      expect { process(:reply_with_8bit_encoding) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("hab vergessen kritische zeichen einzufügen:\näöüÄÖÜß")
    end

    it "prefers text over html when site setting is disabled" do
      SiteSetting.incoming_email_prefer_html = false
      expect { process(:text_and_html_reply) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("This is the *text* part.")
    end

    it "prefers html over text when site setting is enabled" do
      SiteSetting.incoming_email_prefer_html = true
      expect { process(:text_and_html_reply) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq('This is the **html** part.')
    end

    it "uses text when prefer_html site setting is enabled but no html is available" do
      SiteSetting.incoming_email_prefer_html = true
      expect { process(:text_reply) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("This is a text reply :)\n\nEmail parsing should not break because of a UTF-8 character: ’")
    end

    it "removes the 'on <date>, <contact> wrote' quoting line" do
      expect { process(:on_date_contact_wrote) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("This is the actual reply.")
    end

    it "removes the 'Previous Replies' marker" do
      expect { process(:previous_replies) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("This will not include the previous discussion that is present in this email.")
    end

    it "handles multiple paragraphs" do
      expect { process(:paragraphs) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("Do you like liquorice?\n\nI really like them. One could even say that I am *addicted* to liquorice. Anf if\nyou can mix it up with some anise, then I'm in heaven ;)")
    end

    it "handles invalid from header" do
      expect { process(:invalid_from_1) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("This email was sent with an invalid from header field.")
    end

    it "raises a NoSenderDetectedError when the From header doesn't contain an email address" do
      expect { process(:invalid_from_2) }.to raise_error(Email::Receiver::NoSenderDetectedError)
    end

    it "doesn't raise an AutoGeneratedEmailError when the mail is auto generated but is allowlisted" do
      SiteSetting.auto_generated_allowlist = "foo@bar.com|discourse@bar.com"
      expect { process(:auto_generated_allowlisted) }.to change { topic.posts.count }
    end

    it "doesn't raise an AutoGeneratedEmailError when block_auto_generated_emails is disabled" do
      SiteSetting.block_auto_generated_emails = false
      expect { process(:auto_generated_unblocked) }.to change { topic.posts.count }
    end

    it "allows staged users to reply to a restricted category" do
      user.update_columns(staged: true)

      category.email_in = "category@bar.com"
      category.email_in_allow_strangers = true
      category.set_permissions(Group[:trust_level_4] => :full)
      category.save!

      expect { process(:staged_reply_restricted) }.to change { topic.posts.count }
    end

    it "posts a reply to the topic when the post was deleted" do
      post.update_columns(deleted_at: 1.day.ago)
      expect { process(:reply_user_matching) }.to change { topic.posts.count }
      expect(topic.ordered_posts.last.reply_to_post_number).to be_nil
    end

    describe 'Unsubscribing via email' do
      let(:last_email) { ActionMailer::Base.deliveries.last }

      describe 'unsubscribe_subject.eml' do
        it 'sends an email asking the user to confirm the unsubscription' do
          expect { process("unsubscribe_subject") }.to change { ActionMailer::Base.deliveries.count }.by(1)
          expect(last_email.to.length).to eq 1
          expect(last_email.from.length).to eq 1
          expect(last_email.from).to include "noreply@#{Discourse.current_hostname}"
          expect(last_email.to).to include "discourse@bar.com"
          expect(last_email.subject).to eq I18n.t(:"unsubscribe_mailer.subject_template").gsub("%{site_title}", SiteSetting.title)
        end

        it 'does nothing unless unsubscribe_via_email is turned on' do
          SiteSetting.unsubscribe_via_email = false
          before_deliveries = ActionMailer::Base.deliveries.count
          expect { process("unsubscribe_subject") }.to raise_error { Email::Receiver::BadDestinationAddress }
          expect(before_deliveries).to eq ActionMailer::Base.deliveries.count
        end
      end

      describe 'unsubscribe_body.eml' do
        it 'sends an email asking the user to confirm the unsubscription' do
          expect { process("unsubscribe_body") }.to change { ActionMailer::Base.deliveries.count }.by(1)
          expect(last_email.to.length).to eq 1
          expect(last_email.from.length).to eq 1
          expect(last_email.from).to include "noreply@#{Discourse.current_hostname}"
          expect(last_email.to).to include "discourse@bar.com"
          expect(last_email.subject).to eq I18n.t(:"unsubscribe_mailer.subject_template").gsub("%{site_title}", SiteSetting.title)
        end

        it 'does nothing unless unsubscribe_via_email is turned on' do
          SiteSetting.unsubscribe_via_email = false
          before_deliveries = ActionMailer::Base.deliveries.count
          expect { process("unsubscribe_body") }.to raise_error { Email::Receiver::InvalidPost }
          expect(before_deliveries).to eq ActionMailer::Base.deliveries.count
        end
      end

      it "raises an UnsubscribeNotAllowed and does not send an unsubscribe email" do
        before_deliveries = ActionMailer::Base.deliveries.count
        expect { process(:unsubscribe_new_user) }.to raise_error { Email::Receiver::UnsubscribeNotAllowed }
        expect(before_deliveries).to eq ActionMailer::Base.deliveries.count
      end
    end

    it "handles inline reply" do
      expect { process(:inline_reply) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("And this is *my* reply :+1:")
    end

    it "retrieves the first part of multiple replies" do
      expect { process(:inline_mixed_replies) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("> WAT <https://bar.com/users/wat> November 28\n>\n> This is the previous post.\n\nAnd this is *my* reply :+1:\n\n> This is another post.\n\nAnd this is **another** reply.")
    end

    it "strips mobile/webmail signatures" do
      expect { process(:iphone_signature) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("This is not the signature you're looking for.")
    end

    it "strips 'original message' context" do
      expect { process(:original_message) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("This is a reply :)")
    end

    it "add the 'elided' part of the original message only for private messages" do
      topic.update_columns(category_id: nil, archetype: Archetype.private_message)
      topic.allowed_users << user
      topic.save

      expect { process(:original_message) }.to change { topic.posts.count }
      expect(topic.posts.last.raw).to eq("This is a reply :)\n\n<details class='elided'>\n<summary title='Show trimmed content'>&#183;&#183;&#183;</summary>\n\n---Original Message---\nThis part should not be included\n\n</details>")
    end

    it "doesn't include the 'elided' part of the original message when always_show_trimmed_content is disabled" do
      SiteSetting.always_show_trimmed_content = false
      expect { process(:original_message) }.to change { topic.posts.count }.from(1).to(2)
      expect(topic.posts.last.raw).to eq("This is a reply :)")
    end

    it "adds the 'elided' part of the original message for public replies when always_show_trimmed_content is enabled" do
      SiteSetting.always_show_trimmed_content = true
      expect { process(:original_message) }.to change { topic.posts.count }.from(1).to(2)
      expect(topic.posts.last.raw).to eq("This is a reply :)\n\n<details class='elided'>\n<summary title='Show trimmed content'>&#183;&#183;&#183;</summary>\n\n---Original Message---\nThis part should not be included\n\n</details>")
    end

    it "supports attached images in TEXT part" do
      SiteSetting.incoming_email_prefer_html = false

      expect { process(:no_body_with_image) }.to change { topic.posts.count }

      post = topic.posts.last
      upload = post.uploads.first

      expect(post.raw).to include(
        "![#{upload.original_filename}|#{upload.width}x#{upload.height}](#{upload.short_url})"
      )

      expect { process(:inline_image) }.to change { topic.posts.count }

      post = topic.posts.last
      upload = post.uploads.first

      expect(post.raw).to include(
        "![#{upload.original_filename}|#{upload.width}x#{upload.height}](#{upload.short_url})"
      )
    end

    it "supports attached images in HTML part" do
      SiteSetting.incoming_email_prefer_html = true

      expect { process(:inline_image) }.to change { topic.posts.count }

      post = topic.posts.last
      upload = post.uploads.last

      expect(post.raw).to eq(<<~MD.chomp)
      **Before**

      ![#{upload.original_filename}|#{upload.width}x#{upload.height}](#{upload.short_url})

      *After*
      MD
    end

    it "supports attached images in signature" do
      SiteSetting.incoming_email_prefer_html = true
      SiteSetting.always_show_trimmed_content = true

      expect { process(:body_with_image) }.to change { topic.posts.count }

      post = topic.posts.last
      upload = post.uploads.last

      expect(post.raw).to eq(<<~MD.chomp)
      This is a **GMAIL** reply ;)

      <details class='elided'>
      <summary title='Show trimmed content'>&#183;&#183;&#183;</summary>

      ![logo.png|300x200](upload://qUm0DGR49PAZshIi7HxMd3cAlzn.png)

      </details>
      MD
    end

    it "supports attachments" do
      SiteSetting.authorized_extensions = "txt|jpg"
      expect { process(:attached_txt_file) }.to change { topic.posts.count }
      post = topic.posts.last
      upload = post.uploads.first

      expect(post.raw).to eq(<<~MD.chomp)
      Please find some text file attached.

      [#{upload.original_filename}|attachment](#{upload.short_url}) (20 Bytes)
      MD

      expect { process(:apple_mail_attachment) }.to change { topic.posts.count }
      post = topic.posts.last
      upload = post.uploads.first

      expect(post.raw).to eq(<<~MD.chomp)
      Picture below.

      ![#{upload.original_filename}|#{upload.width}x#{upload.height}](#{upload.short_url})

      Picture above.
      MD
    end

    it "works with removed attachments" do
      SiteSetting.authorized_extensions = "jpg"

      expect { process(:removed_attachments) }.to change { topic.posts.count }
      post = topic.posts.last
      expect(post.uploads).to be_empty
    end

    it "supports eml attachments" do
      SiteSetting.authorized_extensions = "eml"
      expect { process(:attached_eml_file) }.to change { topic.posts.count }
      post = topic.posts.last
      upload = post.uploads.first

      expect(post.raw).to eq(<<~MD.chomp)
      Please find the eml file attached.

      [#{upload.original_filename}|attachment](#{upload.short_url}) (193 Bytes)
      MD
    end

    context "when attachment is rejected" do
      it "sends out the warning email" do
        expect { process(:attached_txt_file) }.to change { EmailLog.count }.by(1)
        expect(EmailLog.last.email_type).to eq("email_reject_attachment")
        expect(topic.posts.last.uploads.size).to eq 0
      end

      it "doesn't send out the warning email if sender is staged user" do
        user.update_columns(staged: true)
        expect { process(:attached_txt_file) }.not_to change { EmailLog.count }
        expect(topic.posts.last.uploads.size).to eq 0
      end

      it "creates the post with attachment missing message" do
        missing_attachment_regex = Regexp.escape(I18n.t('emails.incoming.missing_attachment', filename: "text.txt"))
        expect { process(:attached_txt_file) }.to change { topic.posts.count }
        post = topic.posts.last
        expect(post.raw).to match(/#{missing_attachment_regex}/)
        expect(post.uploads.size).to eq 0
      end
    end

    it "supports emails with just an attachment" do
      SiteSetting.authorized_extensions = "pdf"
      expect { process(:attached_pdf_file) }.to change { topic.posts.count }
      post = topic.posts.last
      upload = post.uploads.last

      expect(post.raw).to include(
        "[#{upload.original_filename}|attachment](#{upload.short_url}) (64 KB)"
      )
    end

    it "supports liking via email" do
      expect { process(:like) }.to change(PostAction, :count)
    end

    it "ensures posts aren't dated in the future" do
      # PostCreator doesn't provide sub-second accuracy for created_at
      now = freeze_time Time.zone.now.round

      expect { process(:from_the_future) }.to change { topic.posts.count }
      expect(topic.posts.last.created_at).to eq_time(now)
    end

    it "accepts emails with wrong reply key if the system knows about the forwarded email" do
      Fabricate(:user, email: "bob@bar.com")
      Fabricate(:incoming_email,
                raw: <<~RAW,
                  Return-Path: <discourse@bar.com>
                  From: Alice <discourse@bar.com>
                  To: dave@bar.com, reply+4f97315cc828096c9cb34c6f1a0d6fe8@bar.com
                  CC: carol@bar.com, bob@bar.com
                  Subject: Hello world
                  Date: Fri, 15 Jan 2016 00:12:43 +0100
                  Message-ID: <10@foo.bar.mail>
                  Mime-Version: 1.0
                  Content-Type: text/plain; charset=UTF-8
                  Content-Transfer-Encoding: quoted-printable

                  This post was created by email.
                RAW
                from_address: "discourse@bar.com",
                to_addresses: "dave@bar.com;reply+4f97315cc828096c9cb34c6f1a0d6fe8@bar.com",
                cc_addresses: "carol@bar.com;bob@bar.com",
                topic: topic,
                post: post,
                user: user)

      expect { process(:reply_user_not_matching_but_known) }.to change { topic.posts.count }
    end

    it "re-enables user's PM email notifications when user replies to a private topic" do
      topic.update_columns(category_id: nil, archetype: Archetype.private_message)
      topic.allowed_users << user
      topic.save

      user.user_option.update_columns(email_messages_level: UserOption.email_level_types[:never])
      expect { process(:reply_user_matching) }.to change { topic.posts.count }
      user.reload
      expect(user.user_option.email_messages_level).to eq(UserOption.email_level_types[:always])
    end

  end

  shared_examples "creates topic with forwarded message as quote" do |destination, address|
    it "creates topic with forwarded message as quote" do
      expect { process(:forwarded_email_1) }.to change(Topic, :count)

      topic = Topic.last
      if destination == :category
        expect(topic.category).to eq(Category.where(email_in: address).first)
      else
        expect(topic.archetype).to eq(Archetype.private_message)
        expect(topic.allowed_groups).to eq(Group.where(incoming_email: address))
      end

      post = Post.last

      expect(post.user.email).to eq("ba@bar.com")
      expect(post.raw).to eq(<<~EOF.chomp
        @team, can you have a look at this email below?

        [quote]
        From: Some One &lt;some@one\\.com&gt;
        To: Ba Bar &lt;ba@bar\\.com&gt;
        Date: Mon, 1 Dec 2016 00:13:37 \\+0100
        Subject: Discoursing much?

        Hello Ba Bar,

        Discoursing much today?

        XoXo
        [/quote]
      EOF
      )
    end
  end

  context "new message to a group" do

    fab!(:group) { Fabricate(:group, incoming_email: "team@bar.com|meat@bar.com") }

    it "handles encoded display names" do
      expect { process(:encoded_display_name) }.to change(Topic, :count)

      topic = Topic.last
      expect(topic.title).to eq("I need help")
      expect(topic.private_message?).to eq(true)
      expect(topic.allowed_groups).to include(group)

      user = topic.user
      expect(user.staged).to eq(true)
      expect(user.username).to eq("random.name")
      expect(user.name).to eq("Случайная Имя")
    end

    it "handles email with no subject" do
      expect { process(:no_subject) }.to change(Topic, :count)
      expect(Topic.last.title).to eq("This topic needs a title")
    end

    it "invites everyone in the chain but emails configured as 'incoming' (via reply, group or category)" do
      expect { process(:cc) }.to change(Topic, :count)

      topic = Topic.last

      emails = topic.allowed_users.joins(:user_emails).pluck(:"user_emails.email")
      expect(emails).to contain_exactly("someone@else.com", "discourse@bar.com", "wat@bar.com")

      expect(topic.topic_users.count).to eq(3)
    end

    it "invites users with a secondary email in the chain" do
      user1 = Fabricate(:user,
        trust_level: SiteSetting.email_in_min_trust,
        user_emails: [
          Fabricate.build(:secondary_email, email: "discourse@bar.com"),
          Fabricate.build(:secondary_email, email: "someone@else.com"),
        ]
      )

      user2 = Fabricate(:user,
        trust_level: SiteSetting.email_in_min_trust,
        user_emails: [
          Fabricate.build(:secondary_email, email: "team@bar.com"),
          Fabricate.build(:secondary_email, email: "wat@bar.com"),
        ]
      )

      expect { process(:cc) }.to change(Topic, :count)
      expect(Topic.last.allowed_users).to contain_exactly(user1, user2)
    end

    it "cap the number of staged users created per email" do
      SiteSetting.maximum_staged_users_per_email = 1
      expect { process(:cc) }.to change(Topic, :count)
      expect(Topic.last.ordered_posts[-1].post_type).to eq(Post.types[:moderator_action])
    end

    describe "when 'find_related_post_with_key' is disabled" do
      before do
        SiteSetting.find_related_post_with_key = false
      end

      it "associates email replies using both 'In-Reply-To' and 'References' headers" do
        expect { process(:email_reply_1) }
          .to change(Topic, :count).by(1) & change(Post, :count).by(3)

        topic = Topic.last
        ordered_posts = topic.ordered_posts

        expect(ordered_posts.first.raw).to eq('This is email reply **1**.')

        ordered_posts[1..-1].each do |post|
          expect(post.action_code).to eq('invited_user')
          expect(post.user.email).to eq('one@foo.com')

          expect(%w{two three}.include?(post.custom_fields["action_code_who"]))
            .to eq(true)
        end

        expect { process(:email_reply_2) }.to change { topic.posts.count }.by(1)
        expect { process(:email_reply_3) }.to change { topic.posts.count }.by(1)
        ordered_posts[1..-1].each(&:trash!)
        expect { process(:email_reply_4) }.to change { topic.posts.count }.by(1)
      end
    end

    it "supports any kind of attachments when 'allow_all_attachments_for_group_messages' is enabled" do
      SiteSetting.allow_all_attachments_for_group_messages = true
      expect { process(:attached_rb_file) }.to change(Topic, :count)

      post = Topic.last.first_post
      upload = post.uploads.first

      expect(post.raw).to include(
        "[#{upload.original_filename}|attachment](#{upload.short_url}) (#{upload.filesize} Bytes)"
      )
    end

    it "reenables user's PM email notifications when user emails new topic to group" do
      user = Fabricate(:user, email: "existing@bar.com")
      user.user_option.update_columns(email_messages_level: UserOption.email_level_types[:never])
      expect { process(:group_existing_user) }.to change(Topic, :count)
      user.reload
      expect(user.user_option.email_messages_level).to eq(UserOption.email_level_types[:always])
    end

    context "with forwarded emails behaviour set to create replies" do
      before do
        Fabricate(:group, incoming_email: "some_group@bar.com")
        SiteSetting.forwarded_emails_behaviour = "create_replies"
      end

      it "handles forwarded emails" do
        expect { process(:forwarded_email_1) }.to change(Topic, :count)

        forwarded_post, last_post = *Post.last(2)

        expect(forwarded_post.user.email).to eq("some@one.com")
        expect(last_post.user.email).to eq("ba@bar.com")

        expect(forwarded_post.raw).to match(/XoXo/)
        expect(last_post.raw).to match(/can you have a look at this email below/)

        expect(last_post.post_type).to eq(Post.types[:regular])
      end

      it "handles weirdly forwarded emails" do
        group.add(Fabricate(:user, email: "ba@bar.com"))
        group.save

        SiteSetting.forwarded_emails_behaviour = "create_replies"
        expect { process(:forwarded_email_2) }.to change(Topic, :count)

        forwarded_post, last_post = *Post.last(2)

        expect(forwarded_post.user.email).to eq("some@one.com")
        expect(last_post.user.email).to eq("ba@bar.com")

        expect(forwarded_post.raw).to match(/XoXo/)
        expect(last_post.raw).to match(/can you have a look at this email below/)

        expect(last_post.post_type).to eq(Post.types[:whisper])
      end

      # Who thought this was a good idea?!
      it "doesn't blow up with localized email headers" do
        expect { process(:forwarded_email_3) }.to change(Topic, :count)
      end

      it "adds a small action post to explain who forwarded the email when the sender didn't write anything" do
        expect { process(:forwarded_email_4) }.to change(Topic, :count)

        forwarded_post, last_post = *Post.last(2)

        expect(forwarded_post.user.email).to eq("some@one.com")
        expect(forwarded_post.raw).to match(/XoXo/)

        expect(last_post.user.email).to eq("ba@bar.com")
        expect(last_post.post_type).to eq(Post.types[:small_action])
        expect(last_post.action_code).to eq("forwarded")
      end
    end

    context "with forwarded emails behaviour set to quote" do
      before do
        SiteSetting.forwarded_emails_behaviour = "quote"
      end

      include_examples "creates topic with forwarded message as quote", :group, "team@bar.com|meat@bar.com"
    end

    context "when message sent to a group has no key and find_related_post_with_key is enabled" do
      let!(:topic) do
        process(:email_reply_1)
        Topic.last
      end

      it "creates a reply when the sender and referenced message id are known" do
        expect { process(:email_reply_2) }.to change { topic.posts.count }.by(1).and change { Topic.count }.by(0)
      end

      it "creates a new topic when the sender is not known" do
        IncomingEmail.where(message_id: '34@foo.bar.mail').update(cc_addresses: 'three@foo.com')
        expect { process(:email_reply_2) }.to change { topic.posts.count }.by(0).and change { Topic.count }.by(1)
      end

      it "creates a new topic when the referenced message id is not known" do
        IncomingEmail.where(message_id: '34@foo.bar.mail').update(message_id: '99@foo.bar.mail')
        expect { process(:email_reply_2) }.to change { topic.posts.count }.by(0).and change { Topic.count }.by(1)
      end
    end
  end

  context "new topic in a category" do

    fab!(:category) { Fabricate(:category, email_in: "category@bar.com|category@foo.com", email_in_allow_strangers: false) }

    it "raises a StrangersNotAllowedError when 'email_in_allow_strangers' is disabled" do
      expect { process(:new_user) }.to raise_error(Email::Receiver::StrangersNotAllowedError)
    end

    it "raises an InsufficientTrustLevelError when user's trust level isn't enough" do
      Fabricate(:user, email: "existing@bar.com", trust_level: 3)
      SiteSetting.email_in_min_trust = 4
      expect { process(:existing_user) }.to raise_error(Email::Receiver::InsufficientTrustLevelError)
    end

    it "works" do
      user = Fabricate(:user, email: "existing@bar.com", trust_level: SiteSetting.email_in_min_trust)
      group = Fabricate(:group)

      group.add(user)
      group.save

      category.set_permissions(group => :create_post)
      category.save!

      # raises an InvalidAccess when the user doesn't have the privileges to create a topic
      expect { process(:existing_user) }.to raise_error(Discourse::InvalidAccess)

      category.update_columns(email_in_allow_strangers: true)

      # allows new user to create a topic
      expect { process(:new_user) }.to change(Topic, :count)
    end

    it "creates visible topic for ham" do
      SiteSetting.email_in_spam_header = 'none'

      Fabricate(:user, email: "existing@bar.com", trust_level: SiteSetting.email_in_min_trust)
      expect { process(:existing_user) }.to change { Topic.count }.by(1) # Topic created

      topic = Topic.last
      expect(topic.visible).to eq(true)

      post = Post.last
      expect(post.hidden).to eq(false)
      expect(post.hidden_at).to eq(nil)
      expect(post.hidden_reason_id).to eq(nil)
    end

    it "creates hidden topic for X-Spam-Flag" do
      SiteSetting.email_in_spam_header = 'X-Spam-Flag'

      user = Fabricate(:user, email: "existing@bar.com", trust_level: SiteSetting.email_in_min_trust)
      expect { process(:spam_x_spam_flag) }.to change { ReviewableQueuedPost.count }.by(1)
      expect(user.reload.silenced?).to be(true)
    end

    it "creates hidden topic for X-Spam-Status" do
      SiteSetting.email_in_spam_header = 'X-Spam-Status'

      user = Fabricate(:user, email: "existing@bar.com", trust_level: SiteSetting.email_in_min_trust)
      expect { process(:spam_x_spam_status) }.to change { ReviewableQueuedPost.count }.by(1)
      expect(user.reload.silenced?).to be(true)
    end

    it "creates hidden topic for X-SES-Spam-Verdict" do
      SiteSetting.email_in_spam_header = 'X-SES-Spam-Verdict'

      user = Fabricate(:user, email: "existing@bar.com", trust_level: SiteSetting.email_in_min_trust)
      expect { process(:spam_x_ses_spam_verdict) }.to change { ReviewableQueuedPost.count }.by(1)
      expect(user.reload.silenced?).to be(true)
    end

    it "creates hidden topic for failed Authentication-Results header" do
      SiteSetting.email_in_authserv_id = 'example.com'

      user = Fabricate(:user, email: "existing@bar.com", trust_level: SiteSetting.email_in_min_trust)
      expect { process(:dmarc_fail) }.to change { ReviewableQueuedPost.count }.by(1)
      expect(user.reload.silenced?).to be(false)
    end

    it "adds the 'elided' part of the original message when always_show_trimmed_content is enabled" do
      SiteSetting.always_show_trimmed_content = true

      Fabricate(:user, email: "existing@bar.com", trust_level: SiteSetting.email_in_min_trust)
      expect { process(:forwarded_email_to_category) }.to change { Topic.count }.by(1) # Topic created

      new_post, = Post.last
      expect(new_post.raw).to include("Hi everyone, can you have a look at the email below?", "<summary title='Show trimmed content'>&#183;&#183;&#183;</summary>", "Discoursing much today?")
    end

    it "works when approving is enabled" do
      SiteSetting.approve_unless_trust_level = 4

      Fabricate(:user, email: "tl3@bar.com", trust_level: TrustLevel[3])
      Fabricate(:user, email: "tl4@bar.com", trust_level: TrustLevel[4])

      category.set_permissions(Group[:trust_level_4] => :full)
      category.save!

      Group.refresh_automatic_group!(:trust_level_4)

      expect { process(:tl3_user) }.to raise_error(Email::Receiver::InvalidPost)
      expect { process(:tl4_user) }.to change(Topic, :count)
    end

    it "ignores by case-insensitive title" do
      SiteSetting.ignore_by_title = "foo"
      expect { process(:ignored) }.to_not change(Topic, :count)
    end

    it "associates email from a secondary address with user" do
      user = Fabricate(:user,
        trust_level: SiteSetting.email_in_min_trust,
        user_emails: [
          Fabricate.build(:secondary_email, email: "existing@bar.com")
        ]
      )

      expect { process(:existing_user) }.to change(Topic, :count).by(1)

      topic = Topic.last

      expect(topic.posts.last.raw)
        .to eq("Hey, this is a topic from an existing user ;)")

      expect(topic.user).to eq(user)
    end
  end

  context "new topic in a category that allows strangers" do

    fab!(:category) { Fabricate(:category, email_in: "category@bar.com|category@foo.com", email_in_allow_strangers: true) }

    it "lets an email in from a stranger" do
      expect { process(:new_user) }.to change(Topic, :count)
    end

    it "lets an email in from a high-TL user" do
      Fabricate(:user, email: "tl4@bar.com", trust_level: TrustLevel[4])
      expect { process(:tl4_user) }.to change(Topic, :count)
    end

    it "fails on email from a low-TL user" do
      SiteSetting.email_in_min_trust = 4
      Fabricate(:user, email: "tl3@bar.com", trust_level: TrustLevel[3])
      expect { process(:tl3_user) }.to raise_error(Email::Receiver::InsufficientTrustLevelError)
    end

  end

  context "#reply_by_email_address_regex" do

    before do
      SiteSetting.reply_by_email_address = nil
      SiteSetting.alternative_reply_by_email_addresses = nil
    end

    it "it maches nothing if there is not reply_by_email_address" do
      expect(Email::Receiver.reply_by_email_address_regex).to eq(/$a/)
    end

    it "uses 'reply_by_email_address' site setting" do
      SiteSetting.reply_by_email_address = "foo+%{reply_key}@bar.com"
      expect(Email::Receiver.reply_by_email_address_regex).to eq(/foo\+?(\h{32})?@bar\.com/)
    end

    it "uses 'alternative_reply_by_email_addresses' site setting" do
      SiteSetting.alternative_reply_by_email_addresses = "alt.foo+%{reply_key}@bar.com"
      expect(Email::Receiver.reply_by_email_address_regex).to eq(/alt\.foo\+?(\h{32})?@bar\.com/)
    end

    it "combines both 'reply_by_email' settings" do
      SiteSetting.reply_by_email_address = "foo+%{reply_key}@bar.com"
      SiteSetting.alternative_reply_by_email_addresses = "alt.foo+%{reply_key}@bar.com"
      expect(Email::Receiver.reply_by_email_address_regex).to eq(/foo\+?(\h{32})?@bar\.com|alt\.foo\+?(\h{32})?@bar\.com/)
    end

  end

  context "check_address" do
    before do
      SiteSetting.reply_by_email_address = "foo+%{reply_key}@bar.com"
    end

    it "returns nil when the key is invalid" do
      expect(Email::Receiver.check_address('fake@fake.com')).to be_nil
      expect(Email::Receiver.check_address('foo+4f97315cc828096c9cb34c6f1a0d6fe8@bar.com')).to be_nil
    end

    context "with a valid reply" do
      it "returns the destination when the key is valid" do
        post_reply_key = Fabricate(:post_reply_key,
          reply_key: '4f97315cc828096c9cb34c6f1a0d6fe8'
        )

        dest = Email::Receiver.check_address('foo+4f97315cc828096c9cb34c6f1a0d6fe8@bar.com')

        expect(dest).to eq(post_reply_key)
      end
    end
  end

  context "staged users" do
    before do
      SiteSetting.enable_staged_users = true
    end

    shared_examples "does not create staged users" do |email_name, expected_exception|
      it "does not create staged users" do
        staged_user_count = User.where(staged: true).count
        User.expects(:create).never
        User.expects(:create!).never

        if expected_exception
          expect { process(email_name) }.to raise_error(expected_exception)
        else
          process(email_name)
        end

        expect(User.where(staged: true).count).to eq(staged_user_count)
      end
    end

    shared_examples "cleans up staged users" do |email_name, expected_exception|
      it "cleans up staged users" do
        staged_user_count = User.where(staged: true).count
        expect { process(email_name) }.to raise_error(expected_exception)
        expect(User.where(staged: true).count).to eq(staged_user_count)
      end
    end

    context "when email address is screened" do
      before do
        ScreenedEmail.expects(:should_block?).with("screened@mail.com").returns(true)
      end

      include_examples "does not create staged users", :screened_email, Email::Receiver::ScreenedEmailError
    end

    context "when the mail is auto generated" do
      include_examples "does not create staged users", :auto_generated_header, Email::Receiver::AutoGeneratedEmailError
    end

    context "when email is a bounced email" do
      include_examples "does not create staged users", :bounced_email, Email::Receiver::BouncedEmailError
    end

    context "when the body is blank" do
      include_examples "does not create staged users", :no_body, Email::Receiver::NoBodyDetectedError
    end

    context "when unsubscribe via email is not allowed" do
      include_examples "does not create staged users", :unsubscribe_new_user, Email::Receiver::UnsubscribeNotAllowed
    end

    context "when From email address is not on allowlist" do
      before do
        SiteSetting.allowed_email_domains = "example.com|bar.com"
        Fabricate(:group, incoming_email: "some_group@bar.com")
      end

      include_examples "does not create staged users", :blocklist_allowlist_email, Email::Receiver::EmailNotAllowed
    end

    context "when From email address is on blocklist" do
      before do
        SiteSetting.blocked_email_domains = "email.com|mail.com"
        Fabricate(:group, incoming_email: "some_group@bar.com")
      end

      include_examples "does not create staged users", :blocklist_allowlist_email, Email::Receiver::EmailNotAllowed
    end

    context "blocklist and allowlist for To and Cc" do
      before do
        Fabricate(:group, incoming_email: "some_group@bar.com")
      end

      it "does not create staged users for email addresses not on allowlist" do
        SiteSetting.allowed_email_domains = "mail.com|example.com"
        process(:blocklist_allowlist_email)

        expect(User.find_by_email("alice@foo.com")).to be_nil
        expect(User.find_by_email("bob@foo.com")).to be_nil
        expect(User.find_by_email("carol@example.com")).to be_present
      end

      it "does not create staged users for email addresses on blocklist" do
        SiteSetting.blocked_email_domains = "email.com|foo.com"
        process(:blocklist_allowlist_email)

        expect(User.find_by_email("alice@foo.com")).to be_nil
        expect(User.find_by_email("bob@foo.com")).to be_nil
        expect(User.find_by_email("carol@example.com")).to be_present
      end
    end

    context "when destinations aren't matching any of the incoming emails" do
      include_examples "does not create staged users", :bad_destinations, Email::Receiver::BadDestinationAddress
    end

    context "when email is sent to category" do
      context "when email is sent by a new user and category does not allow strangers" do
        fab!(:category) { Fabricate(:category, email_in: "category@foo.com", email_in_allow_strangers: false) }

        include_examples "does not create staged users", :new_user, Email::Receiver::StrangersNotAllowedError
      end

      context "when email has no date" do
        fab!(:category) { Fabricate(:category, email_in: "category@foo.com", email_in_allow_strangers: true) }

        it "includes the translated string in the error" do
          expect { process(:no_date) }.to raise_error(Email::Receiver::InvalidPost).with_message(I18n.t("system_messages.email_reject_invalid_post_specified.date_invalid"))
        end

        include_examples "does not create staged users", :no_date, Email::Receiver::InvalidPost
      end

      context "with forwarded emails behaviour set to quote" do
        before do
          SiteSetting.forwarded_emails_behaviour = "quote"
        end

        context "with a category which allows strangers" do
          fab!(:category) { Fabricate(:category, email_in: "team@bar.com", email_in_allow_strangers: true) }
          include_examples "creates topic with forwarded message as quote", :category, "team@bar.com"
        end

        context "with a category which doesn't allow strangers" do
          fab!(:category) { Fabricate(:category, email_in: "team@bar.com", email_in_allow_strangers: false) }
          include_examples "cleans up staged users", :forwarded_email_1, Email::Receiver::StrangersNotAllowedError
        end
      end
    end

    context "email is a reply" do
      let(:reply_key) { "4f97315cc828096c9cb34c6f1a0d6fe8" }
      fab!(:category) { Fabricate(:category) }
      fab!(:user) { Fabricate(:user, email: "discourse@bar.com") }
      fab!(:user2) { Fabricate(:user, email: "someone_else@bar.com") }
      fab!(:topic) { create_topic(category: category, user: user) }
      fab!(:post) { create_post(topic: topic, user: user) }

      let!(:post_reply_key) do
        Fabricate(:post_reply_key, reply_key: reply_key, user: user, post: post)
      end

      context "when the email address isn't matching the one we sent the notification to" do
        include_examples "does not create staged users", :reply_user_not_matching, Email::Receiver::ReplyUserNotMatchingError
      end

      context "with forwarded emails behaviour set to create replies" do
        before do
          SiteSetting.forwarded_emails_behaviour = "create_replies"
        end

        context "when a reply contains a forwareded email" do
          include_examples "does not create staged users", :reply_and_forwarded
        end

        context "forwarded email to category that doesn't allow strangers" do
          before do
            category.update!(email_in: "team@bar.com", email_in_allow_strangers: false)
          end

          include_examples "cleans up staged users", :forwarded_email_1, Email::Receiver::StrangersNotAllowedError
        end
      end
    end

    context "replying without key is allowed" do
      fab!(:group) { Fabricate(:group, incoming_email: "team@bar.com") }
      let!(:topic) do
        SiteSetting.find_related_post_with_key = false
        process(:email_reply_1)
        Topic.last
      end

      context "when the topic was deleted" do
        before do
          topic.update_columns(deleted_at: 1.day.ago)
        end

        include_examples "cleans up staged users", :email_reply_staged, Email::Receiver::TopicNotFoundError
      end

      context "when the topic was closed" do
        before do
          topic.update_columns(closed: true)
        end

        include_examples "cleans up staged users", :email_reply_staged, Email::Receiver::TopicClosedError
      end

      context "when they aren't allowed to like a post" do
        before do
          topic.update_columns(archived: true)
        end

        include_examples "cleans up staged users", :email_reply_like, Email::Receiver::InvalidPostAction
      end
    end

    it "does not remove the incoming email record when staged users are deleted" do
      expect { process(:bad_destinations) }.to change { IncomingEmail.count }
        .and raise_error(Email::Receiver::BadDestinationAddress)
      expect(IncomingEmail.last.message_id).to eq("9@foo.bar.mail")
    end
  end

  context "mailing list mirror" do
    fab!(:category) { Fabricate(:mailinglist_mirror_category) }

    before do
      SiteSetting.block_auto_generated_emails = true
    end

    it "should allow creating topic even when email is autogenerated" do
      expect { process(:mailinglist) }.to change { Topic.count }
      expect(IncomingEmail.last.is_auto_generated).to eq(false)
    end

    it "should allow replying without reply key" do
      process(:mailinglist)
      topic = Topic.last

      expect { process(:mailinglist_reply) }.to change { topic.posts.count }
    end

    it "should skip validations for staged users" do
      Fabricate(:user, email: "alice@foo.com", staged: true)
      expect { process(:mailinglist_short_message) }.to change { Topic.count }
    end

    it "should skip validations for regular users" do
      Fabricate(:user, email: "alice@foo.com")
      expect { process(:mailinglist_short_message) }.to change { Topic.count }
    end

    context "read-only category" do
      before do
        category.set_permissions(everyone: :readonly)
        category.save!

        Fabricate(:user, email: "alice@foo.com")
        Fabricate(:user, email: "bob@bar.com")
      end

      it "should allow creating topic within read-only category" do
        expect { process(:mailinglist) }.to change { Topic.count }
      end

      it "should allow replying within read-only category" do
        process(:mailinglist)
        topic = Topic.last

        expect { process(:mailinglist_reply) }.to change { topic.posts.count }
      end
    end

    it "ignores unsubscribe email" do
      SiteSetting.unsubscribe_via_email = true
      Fabricate(:user, email: "alice@foo.com")

      expect { process("mailinglist_unsubscribe") }.to_not change { ActionMailer::Base.deliveries.count }
    end

    it "ignores dmarc fails" do
      expect { process("mailinglist_dmarc_fail") }.to change { Topic.count }

      post = Topic.last.first_post
      expect(post.hidden).to eq(false)
      expect(post.hidden_reason_id).to be_nil
    end
  end

  it "tries to fix unparsable email addresses in To and CC headers" do
    expect { process(:unparsable_email_addresses) }.to raise_error(Email::Receiver::BadDestinationAddress)

    email = IncomingEmail.last
    expect(email.to_addresses).to eq("foo@bar.com")
    expect(email.cc_addresses).to eq("bob@example.com;carol@example.com")
  end

  context "#select_body" do

    let(:email) {
      <<~EOF
      MIME-Version: 1.0
      Date: Tue, 01 Jan 2019 00:00:00 +0300
      Subject: An email with whitespaces
      From: Foo <foo@discourse.org>
      To: bar@discourse.org
      Content-Type: text/plain; charset="UTF-8"

          This is a line that will be stripped
          This is another line that will be stripped

      This is a line that will not be touched.
      This is another line that will not be touched.

      * list

        * sub-list

      - list

        - sub-list

      + list

        + sub-list

      [code]
        1.upto(10).each do |i|
          puts i
        end

      ```
        # comment
      [/code]

          This is going to be stripped too.

      ```
        1.upto(10).each do |i|
          puts i
        end

      [/code]
        # comment
      ```

              This is going to be stripped too.

      Bye!
      EOF
    }

    let(:stripped_text) {
      <<~EOF
      This is a line that will be stripped
      This is another line that will be stripped

      This is a line that will not be touched.
      This is another line that will not be touched.

      * list

        * sub-list

      - list

        - sub-list

      + list

        + sub-list

      [code]
        1.upto(10).each do |i|
          puts i
        end

      ```
        # comment
      [/code]

      This is going to be stripped too.

      ```
        1.upto(10).each do |i|
          puts i
        end

      [/code]
        # comment
      ```

      This is going to be stripped too.

      Bye!
      EOF
    }

    it "strips lines if strip_incoming_email_lines is enabled" do
      SiteSetting.strip_incoming_email_lines = true

      receiver = Email::Receiver.new(email)
      text, elided, format = receiver.select_body
      expect(text).to eq(stripped_text)
    end

    it "works with empty mail body" do
      SiteSetting.strip_incoming_email_lines = true

      email = <<~EOF
        Date: Tue, 01 Jan 2019 00:00:00 +0300
        Subject: An email with whitespaces
        From: Foo <foo@discourse.org>
        To: bar@discourse.org
        Content-Type: text/plain; charset="UTF-8"

        --
        my signature

      EOF

      receiver = Email::Receiver.new(email)
      text, _elided, _format = receiver.select_body
      expect(text).to be_blank
    end
  end

  describe "replying to digest" do
    fab!(:user) { Fabricate(:user) }
    fab!(:digest_message_id) { "7402d8ae-1c6e-44bc-9948-48e007839bcc@localhost" }
    fab!(:email_log) { Fabricate(:email_log,
      user: user,
      email_type: 'digest',
      to_address: user.email,
      message_id: digest_message_id
    )}
    let(:email) {
      <<~EOF
      MIME-Version: 1.0
      Date: Tue, 01 Jan 2019 00:00:00 +0300
      From: someone <#{user.email}>
      To: Discourse <#{SiteSetting.notification_email}>
      Message-ID: <CANtGPwC3ZmWSxnnEuJHfosbtc9d0-ZV02b_7KuyircDt4peDC2@mail.gmail.com>
      In-Reply-To: <#{digest_message_id}>
      Subject: Re: [Discourse] Summary
      References: <#{digest_message_id}>
      Content-Type: text/plain; charset="UTF-8"

      hello there! I like the digest!

      EOF
    }

    before do
      Jobs.run_immediately!
    end

    it 'returns a ReplyToDigestError' do
      expect { Email::Receiver.new(email).process! }.to raise_error(Email::Receiver::ReplyToDigestError)
    end
  end

  context "find_related_post" do

    let(:user) { Fabricate(:user) }
    let(:group) { Fabricate(:group, users: [user]) }

    let (:email_1) { <<~EOF
      MIME-Version: 1.0
      Date: Wed, 01 Jan 2019 12:00:00 +0200
      Message-ID: <7aN1uwcokt2xkfG3iYrpKmiuVhy4w9b5@mail.gmail.com>
      Subject: Lorem ipsum dolor sit amet
      From: Dan Ungureanu <dan@discourse.org>
      To: team-test@discourse.org
      Content-Type: text/plain; charset="UTF-8"

      Lorem ipsum dolor sit amet, consectetur adipiscing elit. Maecenas
      semper, erat tempor sodales commodo, mi diam tempus lorem, in vehicula
      leo libero quis lacus. Nullam justo nunc, sagittis nec metus placerat,
      auctor condimentum neque. Sed risus purus, fermentum eget purus
      porttitor, finibus efficitur orci. Integer tempus mi nec odio
      elementum pulvinar. Pellentesque sed fringilla nulla, ac mollis quam.
      Vivamus semper lacinia scelerisque. Cras urna magna, porttitor nec
      libero quis, congue viverra sapien. Nulla sodales ac tellus a
      suscipit.
      EOF
    }

    let (:post_2) {
      incoming_email = IncomingEmail.find_by(message_id: "7aN1uwcokt2xkfG3iYrpKmiuVhy4w9b5@mail.gmail.com")

      PostCreator.create(user,
        raw: "Vestibulum rutrum tortor vitae arcu varius, non vestibulum ipsum tempor. Integer nibh libero, dignissim eu velit vel, interdum posuere mi. Aliquam erat volutpat. Pellentesque id nulla ultricies, eleifend ipsum non, fringilla purus. Aliquam pretium dolor lobortis urna volutpat, vel consectetur arcu porta. In non erat quis nibh gravida pharetra consequat vel risus. Aliquam rutrum consectetur est ac posuere. Praesent mattis nunc risus, a molestie lectus accumsan porta.",
        topic_id: incoming_email.topic_id
      )
    }

    let (:email_3) { <<~EOF
      MIME-Version: 1.0
      Date: Wed, 01 Jan 2019 12:00:00 +0200
      References: <7aN1uwcokt2xkfG3iYrpKmiuVhy4w9b5@mail.gmail.com> <topic/#{post_2.topic_id}/#{post_2.id}@test.localhost>
      In-Reply-To: <topic/#{post_2.topic_id}/#{post_2.id}@test.localhost>
      Message-ID: <w1vdxT8ebJjZQQp7XyDdEJaSscE9qRjr@mail.gmail.com>
      Subject: Re: Lorem ipsum dolor sit amet
      From: Dan Ungureanu <dan@discourse.org>
      To: team-test@discourse.org
      Content-Type: text/plain; charset="UTF-8"

      Integer mattis suscipit facilisis. Ut ullamcorper libero at faucibus
      sodales. Ut suscipit elit ac dui porta consequat. Suspendisse potenti.
      Nam ut accumsan dui, eget commodo sapien. Etiam ultrices elementum
      cursus. Vivamus et diam et orci lobortis porttitor. Aliquam
      scelerisque ex a imperdiet ornare. Donec interdum laoreet posuere.
      Nulla sagittis, velit id posuere sollicitudin, elit nunc laoreet
      libero, vitae aliquet tortor eros at est. Donec vitae massa vehicula,
      aliquet libero non, porttitor ipsum. Phasellus pellentesque sodales
      lacus eu sagittis. Aliquam ut condimentum nisi. Nulla in placerat
      felis. Sed pellentesque, massa auctor venenatis gravida, risus lorem
      iaculis mi, at hendrerit nisi turpis sit amet metus. Nulla egestas
      ante eget nisi luctus consectetur.
      EOF
    }

    def receive(email_string)
      Email::Receiver.new(email_string,
        destinations: [group]
      ).process!
    end

    it "makes all posts in same topic" do
      expect { receive(email_1) }.to change { Topic.count }.by(1).and change { Post.where(post_type: Post.types[:regular]).count }.by(1)
      expect { post_2 }.to change { Topic.count }.by(0).and change { Post.where(post_type: Post.types[:regular]).count }.by(1)
      expect { receive(email_3) }.to change { Topic.count }.by(0).and change { Post.where(post_type: Post.types[:regular]).count }.by(1)
    end
  end
end