Don't email provider for duplicate claims

If a claimant submits multiple claims we don't want to email the
provider to verify these duplicates.

app/forms/journeys/further_education_payments/claim_submission_form.rb

@@ -4,7 +4,11 @@ class ClaimSubmissionForm < ::ClaimSubmissionBaseForm
       def save
         super
 
-        ClaimMailer.further_education_payment_provider_verification_email(claim).deliver_later
+        unless Policies::FurtherEducationPayments.duplicate_claim?(claim)
+          ClaimMailer.further_education_payment_provider_verification_email(claim).deliver_later
+        end
+
+        true
       end
 
       private

app/models/policies/further_education_payments.rb

@@ -28,5 +28,20 @@ def notify_reply_to_id
     def verification_due_date_for_claim(claim)
       (claim.created_at + 2.weeks).to_date
     end
+
+    def duplicate_claim?(claim)
+      Eligibility
+        .joins(:claim)
+        .where(school_id: claim.eligibility.school_id)
+        .merge(
+          Claim.where(
+            first_name: claim.first_name,
+            surname: claim.surname,
+            email_address: claim.email_address
+          )
+          .where.not(id: claim.id)
+        )
+        .exists?
+    end
   end
 end

spec/forms/journeys/further_education_payments/claim_submission_form_spec.rb

@@ -83,5 +83,20 @@
         )
       )
     end
+
+    it "doesn't email the provider if the claim is a duplicate" do
+      allow(ClaimVerifierJob).to receive(:perform_later)
+
+      allow(ClaimMailer).to(
+        receive(:further_education_payment_provider_verification_email)
+      ).and_return(double(deliver_later: nil))
+
+      2.times { described_class.new(journey_session: journey_session).save }
+
+      expect(ClaimMailer).to(
+        have_received(:further_education_payment_provider_verification_email)
+        .exactly(1).times
+      )
+    end
   end
 end

spec/models/policies/further_education_payments_spec.rb

@@ -0,0 +1,88 @@
+require "rails_helper"
+
+RSpec.describe Policies::FurtherEducationPayments do
+  describe ".duplicate_claim?" do
+    subject { described_class.duplicate_claim?(candidate_claim) }
+
+    let(:existing_claim) do
+      create(
+        :claim,
+        policy: Policies::FurtherEducationPayments,
+        eligibility: eligibility_1,
+        first_name: "Edna",
+        surname: "Krabappel",
+        email_address: "[email protected]"
+      )
+    end
+
+    let(:eligibility_1) do
+      create(
+        :further_education_payments_eligibility,
+        school: create(:school)
+      )
+    end
+
+    let(:eligibility_2) do
+      create(
+        :further_education_payments_eligibility,
+        school: school
+      )
+    end
+
+    let(:candidate_claim) do
+      create(
+        :claim,
+        policy: Policies::FurtherEducationPayments,
+        eligibility: eligibility_2,
+        first_name: first_name,
+        surname: surname,
+        email_address: email_address
+      )
+    end
+
+    context "when the schools are different" do
+      let(:first_name) { existing_claim.first_name }
+      let(:surname) { existing_claim.surname }
+      let(:email_address) { existing_claim.email_address }
+      let(:school) { create(:school) }
+
+      it { is_expected.to be false }
+    end
+
+    context "when the first names are different" do
+      let(:first_name) { existing_claim.first_name + "different" }
+      let(:surname) { existing_claim.surname }
+      let(:email_address) { existing_claim.email_address }
+      let(:school) { existing_claim.eligibility.school }
+
+      it { is_expected.to be false }
+    end
+
+    context "when the last names are different" do
+      let(:first_name) { existing_claim.first_name }
+      let(:surname) { existing_claim.surname + "different" }
+      let(:email_address) { existing_claim.email_address }
+      let(:school) { existing_claim.eligibility.school }
+
+      it { is_expected.to be false }
+    end
+
+    context "when the email_address addresses are different" do
+      let(:first_name) { existing_claim.first_name }
+      let(:surname) { existing_claim.surname }
+      let(:email_address) { "different" + existing_claim.email_address }
+      let(:school) { existing_claim.eligibility.school }
+
+      it { is_expected.to be false }
+    end
+
+    context "when the details match" do
+      let(:first_name) { existing_claim.first_name }
+      let(:surname) { existing_claim.surname }
+      let(:email_address) { existing_claim.email_address }
+      let(:school) { existing_claim.eligibility.school }
+
+      it { is_expected.to be true }
+    end
+  end
+end