discourse/spec/components/topic_view_spec.rb

# frozen_string_literal: true

require 'rails_helper'
require 'topic_view'

describe TopicView do

  fab!(:user) { Fabricate(:user) }
  fab!(:moderator) { Fabricate(:moderator) }
  fab!(:admin) { Fabricate(:admin) }
  fab!(:topic) { Fabricate(:topic) }
  fab!(:evil_trout) { Fabricate(:evil_trout) }
  fab!(:first_poster) { topic.user }
  fab!(:anonymous) { Fabricate(:anonymous) }

  let(:topic_view) { TopicView.new(topic.id, evil_trout) }

  context "preload" do
    it "allows preloading of data" do
      preloaded_topic_view = nil
      preloader = lambda do |view|
        preloaded_topic_view = view
      end

      TopicView.on_preload(&preloader)

      expect(preloaded_topic_view).to eq(nil)
      topic_view
      expect(preloaded_topic_view).to eq(topic_view)

      TopicView.cancel_preload(&preloader)
    end
  end

  it "raises a not found error if the topic doesn't exist" do
    expect { TopicView.new(1231232, evil_trout) }.to raise_error(Discourse::NotFound)
  end

  it "accepts a topic or a topic id" do
    expect(TopicView.new(topic, evil_trout).topic).to eq(topic)
    expect(TopicView.new(topic.id, evil_trout).topic).to eq(topic)
  end

  # see also spec/controllers/topics_controller_spec.rb TopicsController::show::permission errors
  it "raises an error if the user can't see the topic" do
    Guardian.any_instance.expects(:can_see?).with(topic).returns(false)
    expect { topic_view }.to raise_error(Discourse::InvalidAccess)
  end

  it "handles deleted topics" do
    topic.trash!(admin)
    expect { TopicView.new(topic.id, user) }.to raise_error(Discourse::InvalidAccess)
    expect { TopicView.new(topic.id, admin) }.not_to raise_error
  end

  context "filter options" do
    fab!(:p0) { Fabricate(:post, topic: topic) }
    fab!(:p1) { Fabricate(:post, topic: topic, post_type: Post.types[:moderator_action]) }
    fab!(:p2) { Fabricate(:post, topic: topic, post_type: Post.types[:small_action]) }

    it "omits moderator actions and small posts when only_regular is set" do
      tv = TopicView.new(topic.id, nil)
      expect(tv.filtered_post_ids).to eq([p0.id, p1.id, p2.id])

      tv = TopicView.new(topic.id, nil, only_regular: true)
      expect(tv.filtered_post_ids).to eq([p0.id])
    end

    it "omits the first post when exclude_first is set" do
      tv = TopicView.new(topic.id, nil, exclude_first: true)
      expect(tv.filtered_post_ids).to eq([p0.id, p1.id, p2.id])
    end
  end

  context 'custom filters' do
    fab!(:p0) { Fabricate(:post, topic: topic) }
    fab!(:p1) { Fabricate(:post, topic: topic, wiki: true) }

    it 'allows to register custom filters' do
      tv = TopicView.new(topic.id, evil_trout, { filter: 'wiki' })
      expect(tv.filter_posts({ filter: "wiki" })).to eq([p0, p1])

      TopicView.add_custom_filter("wiki") do |posts, topic_view|
        posts.where(wiki: true)
      end

      tv = TopicView.new(topic.id, evil_trout, { filter: 'wiki' })
      expect(tv.filter_posts).to eq([p1])

      tv = TopicView.new(topic.id, evil_trout, { filter: 'whatever' })
      expect(tv.filter_posts).to eq([p0, p1])

      ensure
        TopicView.instance_variable_set(:@custom_filters, {})
    end
  end

  context "setup_filtered_posts" do
    describe "filters posts with ignored users" do
      fab!(:ignored_user) { Fabricate(:ignored_user, user: evil_trout, ignored_user: user) }
      let!(:post) { Fabricate(:post, topic: topic, user: first_poster) }
      let!(:post2) { Fabricate(:post, topic: topic, user: evil_trout) }
      let!(:post3) { Fabricate(:post, topic: topic, user: user) }

      it "filters out ignored user posts" do
        tv = TopicView.new(topic.id, evil_trout)
        expect(tv.filtered_post_ids).to eq([post.id, post2.id])
      end

      it "returns nil for next_page" do
        tv = TopicView.new(topic.id, evil_trout)
        expect(tv.next_page).to eq(nil)
      end

      describe "when an ignored user made the original post" do
        let!(:post) { Fabricate(:post, topic: topic, user: user) }

        it "filters out ignored user posts only" do
          tv = TopicView.new(topic.id, evil_trout)
          expect(tv.filtered_post_ids).to eq([post.id, post2.id])
        end
      end

      describe "when an anonymous user made a post" do
        let!(:post4) { Fabricate(:post, topic: topic, user: anonymous) }

        it "filters out ignored user posts only" do
          tv = TopicView.new(topic.id, evil_trout)
          expect(tv.filtered_post_ids).to eq([post.id, post2.id, post4.id])
        end
      end

      describe "when an anonymous (non signed-in) user is viewing a Topic" do
        let!(:post4) { Fabricate(:post, topic: topic, user: anonymous) }

        it "filters out ignored user posts only" do
          tv = TopicView.new(topic.id, nil)
          expect(tv.filtered_post_ids).to eq([post.id, post2.id, post3.id, post4.id])
        end
      end

      describe "when a staff user is ignored" do
        let!(:admin) { Fabricate(:user, admin: true) }
        let!(:admin_ignored_user) { Fabricate(:ignored_user, user: evil_trout, ignored_user: admin) }
        let!(:post4) { Fabricate(:post, topic: topic, user: admin) }

        it "filters out ignored user excluding the staff user" do
          tv = TopicView.new(topic.id, evil_trout)
          expect(tv.filtered_post_ids).to eq([post.id, post2.id, post4.id])
        end
      end
    end
  end

  context "chunk_size" do
    it "returns `chunk_size` by default" do
      expect(TopicView.new(topic.id, evil_trout).chunk_size).to eq(TopicView.chunk_size)
    end

    it "returns `print_chunk_size` when print param is true" do
      tv = TopicView.new(topic.id, evil_trout, print: true)
      expect(tv.chunk_size).to eq(TopicView.print_chunk_size)
    end
  end

  context "with a few sample posts" do
    fab!(:p1) { Fabricate(:post, topic: topic, user: first_poster, percent_rank: 1) }
    fab!(:p2) { Fabricate(:post, topic: topic, user: evil_trout, percent_rank: 0.5) }
    fab!(:p3) { Fabricate(:post, topic: topic, user: first_poster, percent_rank: 0) }

    it "it can find the best responses" do

      best2 = TopicView.new(topic.id, evil_trout, best: 2)
      expect(best2.posts.count).to eq(2)
      expect(best2.posts[0].id).to eq(p2.id)
      expect(best2.posts[1].id).to eq(p3.id)

      topic.update_status('closed', true, admin)
      expect(topic.posts.count).to eq(4)

      # should not get the status post
      best = TopicView.new(topic.id, nil, best: 99)
      expect(best.posts.count).to eq(2)
      expect(best.filtered_post_ids.size).to eq(3)
      expect(best.posts.pluck(:id)).to match_array([p2.id, p3.id])

      # should get no results for trust level too low
      best = TopicView.new(topic.id, nil, best: 99, min_trust_level: evil_trout.trust_level + 1)
      expect(best.posts.count).to eq(0)

      # should filter out the posts with a score that is too low
      best = TopicView.new(topic.id, nil, best: 99, min_score: 99)
      expect(best.posts.count).to eq(0)

      # should filter out everything if min replies not met
      best = TopicView.new(topic.id, nil, best: 99, min_replies: 99)
      expect(best.posts.count).to eq(0)

      # should punch through posts if the score is high enough
      p2.update_column(:score, 100)

      best = TopicView.new(topic.id, nil, best: 99, bypass_trust_level_score: 100, min_trust_level: evil_trout.trust_level + 1)
      expect(best.posts.count).to eq(1)

      # 0 means ignore
      best = TopicView.new(topic.id, nil, best: 99, bypass_trust_level_score: 0, min_trust_level: evil_trout.trust_level + 1)
      expect(best.posts.count).to eq(0)

      # If we restrict to posts a moderator liked, return none
      best = TopicView.new(topic.id, nil, best: 99, only_moderator_liked: true)
      expect(best.posts.count).to eq(0)

      # It doesn't count likes from admins
      PostActionCreator.like(admin, p3)
      best = TopicView.new(topic.id, nil, best: 99, only_moderator_liked: true)
      expect(best.posts.count).to eq(0)

      # It should find the post liked by the moderator
      PostActionCreator.like(moderator, p2)
      best = TopicView.new(topic.id, nil, best: 99, only_moderator_liked: true)
      expect(best.posts.count).to eq(1)

    end

    it "raises NotLoggedIn if the user isn't logged in and is trying to view a private message" do
      Topic.any_instance.expects(:private_message?).returns(true)
      expect { TopicView.new(topic.id, nil) }.to raise_error(Discourse::NotLoggedIn)
    end

    context 'log_check_personal_message is enabled' do
      fab!(:group) { Fabricate(:group) }
      fab!(:private_message) { Fabricate(:private_message_topic, allowed_groups: [group]) }

      before do
        SiteSetting.log_personal_messages_views = true
        evil_trout.admin = true
      end

      it "logs view if Admin views personal message for other user/group" do
        allowed_user = private_message.topic_allowed_users.first.user
        TopicView.new(private_message.id, allowed_user)
        expect(UserHistory.where(action: UserHistory.actions[:check_personal_message]).count).to eq(0)

        TopicView.new(private_message.id, evil_trout)
        expect(UserHistory.where(action: UserHistory.actions[:check_personal_message]).count).to eq(1)
      end

      it "does not log personal message view for group he belongs to" do
        group.users << evil_trout
        TopicView.new(private_message.id, evil_trout)
        expect(UserHistory.where(action: UserHistory.actions[:check_personal_message]).count).to eq(0)
      end

      it "does not log personal message view for his own personal message" do
        private_message.allowed_users << evil_trout
        TopicView.new(private_message.id, evil_trout)
        expect(UserHistory.where(action: UserHistory.actions[:check_personal_message]).count).to eq(0)
      end

      it "does not log personal message view if user can't see the message" do
        expect { TopicView.new(private_message.id, user) }.to raise_error(Discourse::InvalidAccess)
        expect(UserHistory.where(action: UserHistory.actions[:check_personal_message]).count).to eq(0)
      end

      it "does not log personal message view if there exists a similar log in previous hour" do
        2.times { TopicView.new(private_message.id, evil_trout) }
        expect(UserHistory.where(action: UserHistory.actions[:check_personal_message]).count).to eq(1)

        freeze_time (2.hours.from_now)

        TopicView.new(private_message.id, evil_trout)
        expect(UserHistory.where(action: UserHistory.actions[:check_personal_message]).count).to eq(2)
      end
    end

    it "provides an absolute url" do
      expect(topic_view.absolute_url).to eq("http://test.localhost/t/#{topic.slug}/#{topic.id}")
    end

    context 'subfolder' do
      it "provides the correct absolute url" do
        set_subfolder "/forum"
        expect(topic_view.absolute_url).to eq("http://test.localhost/forum/t/#{topic.slug}/#{topic.id}")
      end
    end

    it "provides a summary of the first post" do
      expect(topic_view.summary).to be_present
    end

    describe "#get_canonical_path" do
      fab!(:topic) { Fabricate(:topic) }
      let(:path) { "/1234" }

      before do
        topic.stubs(:relative_url).returns(path)
        TopicView.any_instance.stubs(:find_topic).with(1234).returns(topic)
      end

      it "generates canonical path correctly" do
        expect(TopicView.new(1234, user).canonical_path).to eql(path)
        expect(TopicView.new(1234, user, page: 5).canonical_path).to eql("/1234?page=5")
      end

      it "generates a canonical correctly for paged results" do
        5.times { |i| Fabricate(:post, post_number: i + 1, topic: topic) }

        expect(TopicView.new(1234, user, post_number: 5, limit: 2)
          .canonical_path).to eql("/1234?page=3")
      end

      it "generates canonical path correctly by skipping whisper posts" do
        2.times { |i| Fabricate(:post, post_number: i + 1, topic: topic) }
        2.times { |i| Fabricate(:whisper, post_number: i + 3, topic: topic) }
        Fabricate(:post, post_number: 5, topic: topic)

        expect(TopicView.new(1234, user, post_number: 5, limit: 2)
          .canonical_path).to eql("/1234?page=2")
      end

      it "generates canonical path correctly for mega topics" do
        2.times { |i| Fabricate(:post, post_number: i + 1, topic: topic) }
        2.times { |i| Fabricate(:whisper, post_number: i + 3, topic: topic) }
        Fabricate(:post, post_number: 5, topic: topic)

        expect(TopicView.new(1234, user, post_number: 5, limit: 2, is_mega_topic: true)
          .canonical_path).to eql("/1234?page=3")
      end
    end

    describe "#next_page" do
      let!(:post) { Fabricate(:post, topic: topic, user: user) }
      let!(:post2) { Fabricate(:post, topic: topic, user: user) }
      let!(:post3) { Fabricate(:post, topic: topic, user: user) }
      let!(:post4) { Fabricate(:post, topic: topic, user: user) }
      let!(:post5) { Fabricate(:post, topic: topic, user: user) }

      before do
        TopicView.stubs(:chunk_size).returns(2)
      end

      it "should return the next page" do
        expect(TopicView.new(topic.id, user, { post_number: post.post_number }).next_page).to eql(3)
      end
    end

    context '.post_counts_by_user' do
      it 'returns the two posters with their appropriate counts' do
        Fabricate(:post, topic: topic, user: evil_trout, post_type: Post.types[:whisper])
        # Should not be counted
        Fabricate(:post, topic: topic, user: evil_trout, post_type: Post.types[:whisper], action_code: 'assign')

        expect(TopicView.new(topic.id, admin).post_counts_by_user.to_a).to match_array([[first_poster.id, 2], [evil_trout.id, 2]])

        expect(TopicView.new(topic.id, first_poster).post_counts_by_user.to_a).to match_array([[first_poster.id, 2], [evil_trout.id, 1]])
      end

      it "doesn't return counts for posts with authors who have been deleted" do
        p2.user_id = nil
        p2.save!

        expect(topic_view.post_counts_by_user.to_a).to match_array([[first_poster.id, 2]])
      end
    end

    context '.participants' do
      it 'returns the two participants hashed by id' do
        expect(topic_view.participants.to_a).to match_array([[first_poster.id, first_poster], [evil_trout.id, evil_trout]])
      end
    end

    context '.all_post_actions' do
      it 'is blank at first' do
        expect(topic_view.all_post_actions).to be_blank
      end

      it 'returns the like' do
        PostActionCreator.like(evil_trout, p1)
        expect(topic_view.all_post_actions[p1.id][PostActionType.types[:like]]).to be_present
      end
    end

    context '.read?' do
      it 'tracks correctly' do
        # anon is assumed to have read everything
        expect(TopicView.new(topic.id).read?(1)).to eq(true)

        # random user has nothing
        expect(topic_view.read?(1)).to eq(false)

        evil_trout.created_at = 2.days.ago

        # a real user that just read it should have it marked
        PostTiming.process_timings(evil_trout, topic.id, 1, [[1, 1000]])
        expect(TopicView.new(topic.id, evil_trout).read?(1)).to eq(true)
        expect(TopicView.new(topic.id, evil_trout).topic_user).to be_present
      end
    end

    context "#user_post_bookmarks" do
      let!(:user) { Fabricate(:user) }
      let!(:bookmark1) { Fabricate(:bookmark, post: Fabricate(:post, topic: topic), user: user) }
      let!(:bookmark2) { Fabricate(:bookmark, post: Fabricate(:post, topic: topic), user: user) }
      let!(:bookmark3) { Fabricate(:bookmark, post: Fabricate(:post, topic: topic)) }

      it "returns all the bookmarks in the topic for a user" do
        expect(TopicView.new(topic.id, user).user_post_bookmarks.pluck(:id)).to match_array(
          [bookmark1.id, bookmark2.id]
        )
      end
    end

    context "#first_post_bookmark_reminder_at" do
      let!(:user) { Fabricate(:user) }
      let!(:bookmark1) { Fabricate(:bookmark_next_business_day_reminder, post: topic.first_post, user: user) }

      it "gets the first post bookmark reminder at for the user" do
        expect(TopicView.new(topic.id, user).first_post_bookmark_reminder_at).to eq_time(bookmark1.reminder_at)
      end

      context "when the topic is deleted" do
        it "gets the first post bookmark reminder at for the user" do
          topic_view = TopicView.new(topic, user)
          PostDestroyer.new(Fabricate(:admin), topic.first_post).destroy
          topic.reload
          expect(topic_view.first_post_bookmark_reminder_at).to eq_time(bookmark1.reminder_at)
        end
      end
    end

    context '.topic_user' do
      it 'returns nil when there is no user' do
        expect(TopicView.new(topic.id, nil).topic_user).to be_blank
      end
    end

    context '#recent_posts' do
      before do
        24.times do |t| # our let()s have already created 3
          Fabricate(:post, topic: topic, user: first_poster, created_at: t.seconds.from_now)
        end
      end

      it 'returns at most 25 recent posts ordered newest first' do
        recent_posts = topic_view.recent_posts

        # count
        expect(recent_posts.count).to eq(25)

        # ordering
        expect(recent_posts.include?(p1)).to eq(false)
        expect(recent_posts.include?(p3)).to eq(true)
        expect(recent_posts.first.created_at).to be > recent_posts.last.created_at
      end
    end

  end

  context 'whispers' do
    it "handles their visibility properly" do
      p1 = Fabricate(:post, topic: topic, user: evil_trout)
      p2 = Fabricate(:post, topic: topic, user: evil_trout, post_type: Post.types[:whisper])
      p3 = Fabricate(:post, topic: topic, user: evil_trout)

      ch_posts = TopicView.new(topic.id, evil_trout).posts
      expect(ch_posts.map(&:id)).to eq([p1.id, p2.id, p3.id])

      anon_posts = TopicView.new(topic.id).posts
      expect(anon_posts.map(&:id)).to eq([p1.id, p3.id])

      admin_posts = TopicView.new(topic.id, moderator).posts
      expect(admin_posts.map(&:id)).to eq([p1.id, p2.id, p3.id])
    end
  end

  context '#posts' do

    # Create the posts in a different order than the sort_order
    let!(:p5) { Fabricate(:post, topic: topic, user: evil_trout) }
    let!(:p2) { Fabricate(:post, topic: topic, user: evil_trout) }
    let!(:p6) { Fabricate(:post, topic: topic, user: user, deleted_at: Time.now) }
    let!(:p4) { Fabricate(:post, topic: topic, user: evil_trout, deleted_at: Time.now) }
    let!(:p1) { Fabricate(:post, topic: topic, user: first_poster) }
    let!(:p7) { Fabricate(:post, topic: topic, user: evil_trout, deleted_at: Time.now) }
    let!(:p3) { Fabricate(:post, topic: topic, user: first_poster) }

    before do
      TopicView.stubs(:chunk_size).returns(3)

      # Update them to the sort order we're checking for
      [p1, p2, p3, p4, p5, p6, p7].each_with_index do |p, idx|
        p.sort_order = idx + 1
        p.save
      end
      p6.user_id = nil # user got nuked
      p6.save!
    end

    describe "contains_gaps?" do
      it "works" do
        # does not contain contains_gaps with default filtering
        expect(topic_view.contains_gaps?).to eq(false)
        # contains contains_gaps when filtered by username" do
        expect(TopicView.new(topic.id, evil_trout, username_filters: ['eviltrout']).contains_gaps?).to eq(true)
        # contains contains_gaps when filtered by summary
        expect(TopicView.new(topic.id, evil_trout, filter: 'summary').contains_gaps?).to eq(true)
        # contains contains_gaps when filtered by best
        expect(TopicView.new(topic.id, evil_trout, best: 5).contains_gaps?).to eq(true)
      end
    end

    it "#restricts to correct topic" do
      t2 = Fabricate(:topic)

      category = Fabricate(:category, name: "my test")
      category.set_permissions(Group[:admins] => :full)
      category.save

      topic.category_id = category.id
      topic.save!

      expect {
        TopicView.new(topic.id, evil_trout).posts.count
      }.to raise_error(Discourse::InvalidAccess)

      expect(TopicView.new(t2.id, evil_trout, post_ids: [p1.id, p2.id]).posts.count).to eq(0)

    end

    describe '#filter_posts_paged' do
      before { TopicView.stubs(:chunk_size).returns(2) }

      it 'returns correct posts for all pages' do
        expect(topic_view.filter_posts_paged(1)).to eq([p1, p2])
        expect(topic_view.filter_posts_paged(2)).to eq([p3, p5])
        expect(topic_view.filter_posts_paged(3)).to eq([])
        expect(topic_view.filter_posts_paged(100)).to eq([])
      end
    end

    describe '#filter_posts_by_post_number' do
      def create_topic_view(post_number)
        TopicView.new(
          topic.id,
          evil_trout,
          filter_post_number: post_number,
          asc: asc
        )
      end

      describe 'ascending' do
        let(:asc) { true }

        it 'should return the right posts' do
          topic_view = create_topic_view(p3.post_number)

          expect(topic_view.posts).to eq([p5])

          topic_view = create_topic_view(p6.post_number)
          expect(topic_view.posts).to eq([])
        end
      end

      describe 'descending' do
        let(:asc) { false }

        it 'should return the right posts' do
          topic_view = create_topic_view(p7.post_number)

          expect(topic_view.posts).to eq([p5, p3, p2])

          topic_view = create_topic_view(p2.post_number)

          expect(topic_view.posts).to eq([p1])
        end
      end
    end

    describe "filter_posts_near" do

      def topic_view_near(post, show_deleted = false)
        TopicView.new(topic.id, evil_trout, post_number: post.post_number, show_deleted: show_deleted)
      end

      it "snaps to the lower boundary" do
        near_view = topic_view_near(p1)
        expect(near_view.desired_post).to eq(p1)
        expect(near_view.posts).to eq([p1, p2, p3])
        expect(near_view.contains_gaps?).to eq(false)
      end

      it "snaps to the upper boundary" do
        near_view = topic_view_near(p5)
        expect(near_view.desired_post).to eq(p5)
        expect(near_view.posts).to eq([p2, p3, p5])
        expect(near_view.contains_gaps?).to eq(false)
      end

      it "returns the posts in the middle" do
        near_view = topic_view_near(p2)
        expect(near_view.desired_post).to eq(p2)
        expect(near_view.posts).to eq([p1, p2, p3])
        expect(near_view.contains_gaps?).to eq(false)
      end

      describe 'when post_number is too large' do
        it "snaps to the lower boundary" do
          near_view = TopicView.new(topic.id, evil_trout,
            post_number: 99999999,
          )

          expect(near_view.desired_post).to eq(p2)
          expect(near_view.posts).to eq([p2, p3, p5])
          expect(near_view.contains_gaps?).to eq(false)
        end
      end

      it "gaps deleted posts to an admin" do
        evil_trout.admin = true
        near_view = topic_view_near(p3)
        expect(near_view.desired_post).to eq(p3)
        expect(near_view.posts).to eq([p2, p3, p5])
        expect(near_view.gaps.before).to eq(p5.id => [p4.id])
        expect(near_view.gaps.after).to eq(p5.id => [p6.id, p7.id])
      end

      it "returns deleted posts to an admin with show_deleted" do
        evil_trout.admin = true
        near_view = topic_view_near(p3, true)
        expect(near_view.desired_post).to eq(p3)
        expect(near_view.posts).to eq([p2, p3, p4])
        expect(near_view.contains_gaps?).to eq(false)
      end

      it "gaps deleted posts by nuked users to an admin" do
        evil_trout.admin = true
        near_view = topic_view_near(p5)
        expect(near_view.desired_post).to eq(p5)
        # note: both p4 and p6 get skipped
        expect(near_view.posts).to eq([p2, p3, p5])
        expect(near_view.gaps.before).to eq(p5.id => [p4.id])
        expect(near_view.gaps.after).to eq(p5.id => [p6.id, p7.id])
      end

      it "returns deleted posts by nuked users to an admin with show_deleted" do
        evil_trout.admin = true
        near_view = topic_view_near(p5, true)
        expect(near_view.desired_post).to eq(p5)
        expect(near_view.posts).to eq([p4, p5, p6])
        expect(near_view.contains_gaps?).to eq(false)
      end

      context "when 'posts per page' exceeds the number of posts" do
        before { TopicView.stubs(:chunk_size).returns(100) }

        it 'returns all the posts' do
          near_view = topic_view_near(p5)
          expect(near_view.posts).to eq([p1, p2, p3, p5])
          expect(near_view.contains_gaps?).to eq(false)
        end

        it 'gaps deleted posts to admins' do
          evil_trout.admin = true
          near_view = topic_view_near(p5)
          expect(near_view.posts).to eq([p1, p2, p3, p5])
          expect(near_view.gaps.before).to eq(p5.id => [p4.id])
          expect(near_view.gaps.after).to eq(p5.id => [p6.id, p7.id])
        end

        it 'returns deleted posts to admins' do
          evil_trout.admin = true
          near_view = topic_view_near(p5, true)
          expect(near_view.posts).to eq([p1, p2, p3, p4, p5, p6, p7])
          expect(near_view.contains_gaps?).to eq(false)
        end
      end
    end
  end

  context "page_title" do
    fab!(:tag1) { Fabricate(:tag) }
    fab!(:tag2) { Fabricate(:tag, topic_count: 2) }
    fab!(:op_post) { Fabricate(:post, topic: topic) }
    fab!(:post1) { Fabricate(:post, topic: topic) }
    fab!(:whisper) { Fabricate(:post, topic: topic, post_type: Post.types[:whisper]) }

    subject { TopicView.new(topic.id, evil_trout).page_title }

    context "when a post number is specified" do
      context "admins" do
        it "see post number and username for all posts" do
          title = TopicView.new(topic.id, admin, post_number: 0).page_title
          expect(title).to eq(topic.title)
          title = TopicView.new(topic.id, admin, post_number: 1).page_title
          expect(title).to eq(topic.title)

          title = TopicView.new(topic.id, admin, post_number: 2).page_title
          expect(title).to eq("#{topic.title} - #2 by #{post1.user.username}")
          title = TopicView.new(topic.id, admin, post_number: 3).page_title
          expect(title).to eq("#{topic.title} - #3 by #{whisper.user.username}")
        end
      end

      context "regular users" do
        it "see post number and username for regular posts" do
          title = TopicView.new(topic.id, evil_trout, post_number: 0).page_title
          expect(title).to eq(topic.title)
          title = TopicView.new(topic.id, evil_trout, post_number: 1).page_title
          expect(title).to eq(topic.title)

          title = TopicView.new(topic.id, evil_trout, post_number: 2).page_title
          expect(title).to eq("#{topic.title} - #2 by #{post1.user.username}")
        end

        it "see only post number for whisper posts" do
          title = TopicView.new(topic.id, evil_trout, post_number: 3).page_title
          expect(title).to eq("#{topic.title} - #3")
          post2 = Fabricate(:post, topic: topic)
          topic.reload
          title = TopicView.new(topic.id, evil_trout, post_number: 3).page_title
          expect(title).to eq("#{topic.title} - #3")
          title = TopicView.new(topic.id, evil_trout, post_number: 4).page_title
          expect(title).to eq("#{topic.title} - #4 by #{post2.user.username}")
        end
      end
    end

    context "uncategorized topic" do
      context "topic_page_title_includes_category is false" do
        before { SiteSetting.topic_page_title_includes_category = false }
        it { should eq(topic.title) }
      end

      context "topic_page_title_includes_category is true" do
        before { SiteSetting.topic_page_title_includes_category = true }
        it { should eq(topic.title) }

        context "tagged topic" do
          before { topic.tags << [tag1, tag2] }

          context "tagging enabled" do
            before { SiteSetting.tagging_enabled = true }

            it { should start_with(topic.title) }
            it { should_not include(tag1.name) }
            it { should end_with(tag2.name) } # tag2 has higher topic count
          end

          context "tagging disabled" do
            before { SiteSetting.tagging_enabled = false }

            it { should start_with(topic.title) }
            it { should_not include(tag1.name) }
            it { should_not include(tag2.name) }
          end
        end
      end
    end

    context "categorized topic" do
      let(:category) { Fabricate(:category) }

      before { topic.update(category_id: category.id) }

      context "topic_page_title_includes_category is false" do
        before { SiteSetting.topic_page_title_includes_category = false }
        it { should eq(topic.title) }
      end

      context "topic_page_title_includes_category is true" do
        before { SiteSetting.topic_page_title_includes_category = true }
        it { should start_with(topic.title) }
        it { should end_with(category.name) }

        context "tagged topic" do
          before do
            SiteSetting.tagging_enabled = true
            topic.tags << [tag1, tag2]
          end

          it { should start_with(topic.title) }
          it { should end_with(category.name) }
          it { should_not include(tag1.name) }
          it { should_not include(tag2.name) }
        end
      end
    end
  end

  describe '#filtered_post_stream' do
    let!(:post) { Fabricate(:post, topic: topic, user: first_poster) }
    let!(:post2) { Fabricate(:post, topic: topic, user: evil_trout) }
    let!(:post3) { Fabricate(:post, topic: topic, user: first_poster) }

    it 'should return the right columns' do
      expect(topic_view.filtered_post_stream).to eq([
        [post.id, 0],
        [post2.id, 0],
        [post3.id, 0]
      ])
    end

    describe 'for mega topics' do
      it 'should return the right columns' do
        begin
          original_const = TopicView::MEGA_TOPIC_POSTS_COUNT
          TopicView.send(:remove_const, "MEGA_TOPIC_POSTS_COUNT")
          TopicView.const_set("MEGA_TOPIC_POSTS_COUNT", 2)

          expect(topic_view.filtered_post_stream).to eq([
            post.id,
            post2.id,
            post3.id
          ])
        ensure
          TopicView.send(:remove_const, "MEGA_TOPIC_POSTS_COUNT")
          TopicView.const_set("MEGA_TOPIC_POSTS_COUNT", original_const)
        end
      end
    end
  end

  describe '#filtered_post_id' do
    it 'should return the right id' do
      post = Fabricate(:post, topic: topic)

      expect(topic_view.filtered_post_id(nil)).to eq(nil)
      expect(topic_view.filtered_post_id(post.post_number)).to eq(post.id)
    end
  end

  describe '#first_post_id and #last_post_id' do
    let!(:p3) { Fabricate(:post, topic: topic) }
    let!(:p2) { Fabricate(:post, topic: topic) }
    let!(:p1) { Fabricate(:post, topic: topic) }

    before do
      [p1, p2, p3].each_with_index do |post, index|
        post.update!(sort_order: index + 1)
      end
    end

    it 'should return the right id' do
      expect(topic_view.first_post_id).to eq(p1.id)
      expect(topic_view.last_post_id).to eq(p3.id)
    end
  end

  describe '#read_time' do
    let!(:post) { Fabricate(:post, topic: topic) }

    before do
      PostCreator.create!(Discourse.system_user, topic_id: topic.id, raw: "![image|100x100](upload://upload.png)")
      topic_view.topic.reload
    end

    it 'should return the right read time' do
      SiteSetting.read_time_word_count = 500
      expect(topic_view.read_time).to eq(1)

      SiteSetting.read_time_word_count = 0
      expect(topic_view.read_time).to eq(nil)
    end
  end

  describe '#image_url' do
    fab!(:op_upload) { Fabricate(:image_upload) }
    fab!(:post3_upload) { Fabricate(:image_upload) }

    fab!(:post1) { Fabricate(:post, topic: topic) }
    fab!(:post2) { Fabricate(:post, topic: topic) }
    fab!(:post3) { Fabricate(:post, topic: topic).tap { |p| p.update_column(:image_upload_id, post3_upload.id) }.reload }

    def topic_view_for_post(post_number)
      TopicView.new(topic.id, evil_trout, post_number: post_number)
    end

    context "when op has an image" do
      before do
        topic.update_column(:image_upload_id, op_upload.id)
        post1.update_column(:image_upload_id, op_upload.id)
      end

      it "uses the topic image as a fallback when posts have no image" do
        expect(topic_view_for_post(1).image_url).to end_with(op_upload.url)
        expect(topic_view_for_post(2).image_url).to end_with(op_upload.url)
        expect(topic_view_for_post(3).image_url).to end_with(post3_upload.url)
      end
    end

    context "when op has no image" do
      it "returns nil when posts have no image" do
        expect(topic_view_for_post(1).image_url).to eq(nil)
        expect(topic_view_for_post(2).image_url).to eq(nil)
        expect(topic_view_for_post(3).image_url).to end_with(post3_upload.url)
      end
    end
  end

  describe '#show_read_indicator?' do
    let(:topic) { Fabricate(:topic) }
    let(:pm_topic) { Fabricate(:private_message_topic) }

    it "shows read indicator for private messages" do
      group = Fabricate(:group, users: [admin], publish_read_state: true)
      pm_topic.topic_allowed_groups = [Fabricate.build(:topic_allowed_group, group: group)]

      topic_view = TopicView.new(pm_topic.id, admin)
      expect(topic_view.show_read_indicator?).to be_truthy
    end

    it "does not show read indicator if groups do not have read indicator enabled" do
      topic_view = TopicView.new(pm_topic.id, admin)
      expect(topic_view.show_read_indicator?).to be_falsey
    end

    it "does not show read indicator for topics with allowed groups" do
      group = Fabricate(:group, users: [admin], publish_read_state: true)
      topic.topic_allowed_groups = [Fabricate.build(:topic_allowed_group, group: group)]

      topic_view = TopicView.new(topic.id, admin)
      expect(topic_view.show_read_indicator?).to be_falsey
    end
  end
end