Send email confirmation when BTC payment is confirmed

app/jobs/btcpay_check_donation_job.rb

@@ -4,15 +4,19 @@ class BtcpayCheckDonationJob < ApplicationJob
   def perform(donation)
     return if donation.completed?
 
-    invoice = BtcpayManager::FetchInvoice.call(invoice_id: donation.btcpay_invoice_id)
+    invoice = BtcpayManager::FetchInvoice.call(
+      invoice_id: donation.btcpay_invoice_id
+    )
 
     case invoice["status"]
     when "Settled"
-      # TODO use time from actual payment confirmation
       donation.paid_at = DateTime.now
       donation.payment_status = "settled"
       donation.save!
-      # TODO send email
+
+      NotificationMailer.with(user: donation.user)
+                        .bitcoin_donation_confirmed
+                        .deliver_later
     when "Processing"
       re_enqueue_job(donation)
     end

app/mailers/notification_mailer.rb

@@ -23,4 +23,11 @@ class NotificationMailer < ApplicationMailer
     @subject = "New invitations added to your account"
     mail to: @user.email, subject: @subject
   end
+
+  def bitcoin_donation_confirmed
+    @user = params[:user]
+    @donation = params[:donation]
+    @subject = "Donation confirmed"
+    mail to: @user.email, subject: @subject
+  end
 end

app/views/notification_mailer/bitcoin_donation_confirmed.text.erb

@@ -0,0 +1,11 @@
+Hi <%= @user.display_name.presence || @user.cn %>,
+
+Your bitcoin donation has been confirmed successfully. <3
+
+Thank you so much for helping us with keeping the lights on, as well as with continually improving our services for you!
+
+You can find all of your past financial contributions on this page:
+
+<%= contributions_donations_url %>
+
+Have a nice day!

spec/jobs/btcpay_check_donation_job_spec.rb

@@ -6,12 +6,20 @@ RSpec.describe BtcpayCheckDonationJob, type: :job do
 
   let(:donation) do
     user.donations.create!(
-      donation_method: "btcpay", btcpay_invoice_id: "K4e31MhbLKmr3D7qoNYRd3",
+      donation_method: "btcpay",
+      btcpay_invoice_id: "K4e31MhbLKmr3D7qoNYRd3",
       paid_at: nil, payment_status: "processing",
       fiat_amount: 120, fiat_currency: "USD"
     )
   end
 
+  before do
+    allow_any_instance_of(User).to receive(:ldap_entry).and_return({
+      uid: user.cn, ou: user.ou, mail: user.email, admin: nil,
+      display_name: nil
+    })
+  end
+
   after(:each) do
     clear_enqueued_jobs
     clear_performed_jobs
@@ -48,16 +56,24 @@ RSpec.describe BtcpayCheckDonationJob, type: :job do
     end
 
     it "updates the donation record" do
-      perform_enqueued_jobs { job }
+      perform_enqueued_jobs(only: described_class) { job }
-
       donation.reload
       expect(donation.paid_at).not_to be_nil
       expect(donation.payment_status).to eq("settled")
     end
 
+    it "notifies the user via email" do
+      perform_enqueued_jobs(only: described_class) { job }
+      expect(enqueued_jobs.size).to eq(1)
+      job = enqueued_jobs.select{|j| j['job_class'] == "ActionMailer::MailDeliveryJob"}.first
+      expect(job['arguments'][0]).to eq('NotificationMailer')
+      expect(job['arguments'][1]).to eq('bitcoin_donation_confirmed')
+      expect(job['arguments'][3]['params']['user']['_aj_globalid']).to eq('gid://akkounts/User/1')
+    end
+
     it "does not enqueue itself again" do
       expect_any_instance_of(described_class).not_to receive(:re_enqueue_job)
-      perform_enqueued_jobs { job }
+      perform_enqueued_jobs(only: described_class) { job }
     end
   end
 end