Add Xapian indexing attachment prominence checks

We need to check attachment prominence while updating the Xapian search
index for events.

To achieve the `IncomingMessae#get_body_for_quoting` method needed to be
split, as it was being used for both indexing and displaying the body as
text.

app/models/incoming_message.rb

@@ -579,9 +579,13 @@ def get_body_for_html_display(collapse_quoted_sections = true)
     text.html_safe
   end
 
+  def get_body_for_indexing # rubocop:disable Naming/AccessorMethodName
+    return '' if Ability.guest.cannot?(:read, get_main_body_text_part)
+    get_body_for_text_display
+  end
 
   # Returns text of email for using in quoted section when replying
-  def get_body_for_quoting
+  def get_body_for_text_display # rubocop:disable Naming/AccessorMethodName
     # Get the body text with emails and quoted sections removed
     text = get_main_body_text_folded.dup
     text.gsub!("FOLDED_QUOTED_SECTION", " ")
@@ -622,6 +626,8 @@ def get_attachment_text_clipped
   def _extract_text
     # Extract text from each attachment
     self.get_attachments_for_display.reduce('') { |memo, attachment|
+      return memo if Ability.guest.cannot?(:read, attachment)
+
       memo += MailHandler.get_attachment_text_one_file(attachment.content_type,
                                                        attachment.default_body,
                                                        attachment.charset)
@@ -634,11 +640,11 @@ def _get_attachment_text_internal
 
   # Returns text for indexing
   def get_text_for_indexing_full
-    return get_body_for_quoting + "\n\n" + get_attachment_text_full
+    return get_body_for_indexing + "\n\n" + get_attachment_text_full
   end
   # Used for excerpts in search results, when loading full text would be too slow
   def get_text_for_indexing_clipped
-    return get_body_for_quoting + "\n\n" + get_attachment_text_clipped
+    return get_body_for_indexing + "\n\n" + get_attachment_text_clipped
   end
 
   # Has message arrived "recently"?

app/models/outgoing_message.rb

@@ -330,7 +330,7 @@ def prepare_message_for_resend
   def quoted_part_to_append_to_email
     if message_type == 'followup' && !incoming_message_followup.nil?
       quoted = "\n\n-----Original Message-----\n\n"
-      quoted += incoming_message_followup.get_body_for_quoting
+      quoted += incoming_message_followup.get_body_for_text_display
       quoted += "\n"
     else
       ""

app/views/admin_general/_to_do_list.html.erb

@@ -17,11 +17,11 @@
             <tr>
               <td class="link">
                 <% if item.is_a? IncomingMessage %>
-                  <% if item.get_body_for_quoting.gsub(/[[:space:]]/, "").size == 0 %>
+                  <% if item.get_body_for_text_display.gsub(/[[:space:]]/, "").size == 0 %>
                     <%= link_to "(no body)", admin_raw_email_path(item.raw_email_id) %>
                   <% else %>
                     <%= link_to admin_raw_email_path(item.raw_email_id) do %>
-                      <%= excerpt(item.get_body_for_quoting, "", :radius => 60) %>
+                      <%= excerpt(item.get_body_for_text_display, "", :radius => 60) %>
                     <% end %>
                   <% end %>
                 <% elsif item.is_a? InfoRequest %>

app/views/request/_incoming_correspondence.text.erb

@@ -8,7 +8,7 @@
 
 <%= render_prominence(incoming_message.get_main_body_text_part, format: :text) -%>
 <% if can?(:read, incoming_message.get_main_body_text_part) %>
-<%= incoming_message.get_body_for_quoting %>
+<%= incoming_message.get_body_for_text_display %>
 <% end %>
 <% incoming_message.get_attachments_for_display.each do |a| %>
 <%= _('Attachment:') %> <% if can?(:read, a) %><%= a.display_filename %> (<%= a.display_size %>)<% end %> <%= render_prominence(a, format: :text) -%>

spec/models/incoming_message_spec.rb

@@ -403,11 +403,35 @@
 
   end
 
-  describe '#get_body_for_quoting' do
+  describe '#get_body_for_indexing' do
+    subject { incoming_message.get_body_for_indexing }
+
+    let(:incoming_message) { FactoryBot.build(:incoming_message) }
+
+    context 'guest can read main body part' do
+      it 'returns body for text display' do
+        is_expected.to eq('hereisthetext')
+      end
+    end
+
+    context 'guest cannot read main body part' do
+      before do
+        ability = Object.new.extend(CanCan::Ability)
+        ability.cannot :read, incoming_message.get_main_body_text_part
+        allow(Ability).to receive(:guest).and_return(ability)
+      end
+
+      it 'returns blank string' do
+        is_expected.to eq ''
+      end
+    end
+  end
+
+  describe '#get_body_for_text_display' do
 
     it 'does not incorrectly cache without the FOLDED_QUOTED_SECTION marker' do
       message = FactoryBot.create(:plain_incoming_message)
-      message.get_body_for_quoting
+      message.get_body_for_text_display
       expect(message.get_main_body_text_folded).
         to include('FOLDED_QUOTED_SECTION')
     end