feat: guessed mail don't go to holding pen

Now, the 'Guessing' mechanism will be used when a mail is
received. If there is only one guess produced by this mechanism,
then the mail will go straight to that guess's IR

app/mailers/request_mailer.rb

@@ -235,35 +235,47 @@ def requests_matching_email(email)
     InfoRequest.matching_incoming_email(addresses)
   end
 
+  def send_to_holding_pen(email, raw_email, opts)
+    opts[:rejected_reason] =
+    _("Could not identify the request from the email address")
+    request = InfoRequest.holding_pen_request
+    request.receive(email, raw_email, opts)
+  end
+
   # Member function, called on the new class made in self.receive above
   def receive(email, raw_email, source = :mailin)
     opts = { source: source }
 
-    # Find which info requests the email is for
-    reply_info_requests = requests_matching_email(email)
+    # Only check mail that doesn't have spam in the header
+    return if SpamAddress.spam?(MailHandler.get_all_addresses(email))
 
-    # Nothing found OR multiple different info requests, so save in holding pen
-    if reply_info_requests.empty? || reply_info_requests.count > 1
-      opts[:rejected_reason] =
-        _("Could not identify the request from the email address")
-      request = InfoRequest.holding_pen_request
+    # Find exact matches for info requests
+    exact_info_requests = requests_matching_email(email)
 
-      unless SpamAddress.spam?(MailHandler.get_all_addresses(email))
-        request.receive(email, raw_email, opts)
-      end
-      return
+    # Find any guesses for info requests
+    unless exact_info_requests.count == 1
+      guessed_info_requests = Guess.guessed_info_requests(email)
     end
 
-    # Send the message to each request, to be archived with it
-    reply_info_requests.each do |reply_info_request|
-      # If environment variable STOP_DUPLICATES is set, don't send message with same id again
-      if ENV['STOP_DUPLICATES']
-        if reply_info_request.already_received?(email, raw_email)
-          raise "message #{ email.message_id } already received by request"
-        end
+    # If there is only one info request matching mail, it gets attached to the
+    # request to be archived with it
+    if exact_info_requests.count == 1 || guessed_info_requests.count == 1
+      info_request = exact_info_requests.first || guessed_info_requests.first
+
+      if exact_info_requests.empty? && guessed_info_requests.count == 1
+        info_request.log_event(
+          'redeliver_incoming',
+          editor: 'automatic',
+          destination_request: info_request,
+        )
       end
 
-      reply_info_request.receive(email, raw_email, opts)
+      info_request.receive(email, raw_email, opts)
+
+    else
+      # Otherwise, if there are no matching IRs, multiple IRs, or multiple IR
+      # guesses, we send the mail to the holding pen
+      send_to_holding_pen(email, raw_email, opts)
     end
   end
 

app/models/guess.rb

@@ -6,6 +6,29 @@
 class Guess
   attr_reader :info_request, :components
 
+  # The percentage similarity the id or idhash much fulfil
+  THRESHOLD = 0.8
+
+  ##
+  # Return InfoRequest which we guess should receive an incoming message based
+  # on a threshold.
+  #
+  def self.guessed_info_requests(email)
+    # Match the email address in the message without matching the hash
+    email_addresses = MailHandler.get_all_addresses(email)
+    guesses = InfoRequest.guess_by_incoming_email(email_addresses)
+
+    guesses_reaching_threshold = guesses.select do |ir_guess|
+      id_score = ir_guess.id_score
+      idhash_score = ir_guess.idhash_score
+
+      (id_score == 1 && idhash_score >= THRESHOLD) ||
+        (id_score >= THRESHOLD && idhash_score == 1)
+    end
+
+    guesses_reaching_threshold.map(&:info_request).uniq
+  end
+
   def initialize(info_request, **components)
     @info_request = info_request
     @components = components

spec/integration/admin_spec.rb

@@ -127,26 +127,6 @@
         expect(page).to have_content "Only the authority can reply to this request"
       end
     end
-
-    it "guesses a misdirected request" do
-      info_request = FactoryBot.create(:info_request,
-                                       allow_new_responses_from: 'authority_only',
-                                       handle_rejected_responses: 'holding_pen')
-      mail_to = "request-#{info_request.id}-asdfg@example.com"
-      receive_incoming_mail('incoming-request-plain.email', email_to: mail_to)
-      interesting_email = last_holding_pen_mail
-
-      # now we add another message to the queue, which we're not interested in
-      receive_incoming_mail('incoming-request-plain.email',
-                            email_to: info_request.incoming_email,
-                            email_from: "")
-      expect(holding_pen_messages.length).to eq(2)
-      using_session(@admin) do
-        visit admin_raw_email_path interesting_email
-        expect(page).to have_content "Could not identify the request"
-        expect(page).to have_content info_request.title
-      end
-    end
   end
 
   describe 'generating an upload url' do

spec/mailers/request_mailer_spec.rb

@@ -24,6 +24,25 @@
       deliveries.clear
     end
 
+    it "should append it to the appropriate request if there is only one guess of information request" do
+      ir = info_requests(:fancy_dog_request)
+      expect(ir.incoming_messages.count).to eq(1) # in the fixture
+      receive_incoming_mail(
+        'incoming-request-plain.email',
+        email_to: "request-#{ir.id}-#{ir.idhash}a@localhost"
+      )
+      expect(ir.incoming_messages.count).to eq(2) # one more arrives
+      expect(ir.info_request_events[-1].incoming_message_id).not_to be_nil
+      expect(ir.info_request_events[-2].params[:editor]).to eq("automatic")
+
+      deliveries = ActionMailer::Base.deliveries
+      expect(deliveries.size).to eq(1)
+      mail = deliveries[0]
+      # to the user who sent fancy_dog_request
+      expect(mail.to).to eq(['bob@localhost'])
+      deliveries.clear
+    end
+
     it "should store mail in holding pen and send to admin when the email is not to any information request" do
       ir = info_requests(:fancy_dog_request)
       expect(ir.incoming_messages.count).to eq(1)

spec/models/guess_spec.rb

@@ -5,6 +5,46 @@
     FactoryBot.create(:info_request, id: 100, idhash: '4e637388')
   end
 
+  describe '.guessed_info_requests' do
+    subject(:guesses) { described_class.guessed_info_requests(email) }
+
+    let(:email) do
+      mail = Mail.new
+      mail.to address
+      mail
+    end
+
+    let(:info_request) { FactoryBot.create(:info_request, id: 4566) }
+    let!(:other_info_request) { FactoryBot.create(:info_request) }
+
+    let(:id) { info_request.id }
+    let(:hash) { info_request.idhash }
+
+    context 'with email matching ID and ID hash' do
+      let(:address) { info_request.incoming_email }
+
+      it 'return matching InfoRequest' do
+        is_expected.to match_array([info_request])
+      end
+    end
+
+    context 'with email matching ID and almost ID hash' do
+      let(:address) { "request-#{id}-#{hash[0...-1]}}z@localhost" }
+
+      it 'return guessed InfoRequest' do
+        is_expected.to match_array([info_request])
+      end
+    end
+
+    context 'with email matching ID hash and almost ID' do
+      let(:address) { "request-#{id.to_s[0...-1]}-#{hash}@localhost" }
+
+      it 'return guessed InfoRequest' do
+        is_expected.to match_array([info_request])
+      end
+    end
+  end
+
   describe 'with a subject line given' do
     let(:guess) { described_class.new(info_request, subject: 'subject_line') }