Add available credit on the admin customer page

app/queries/customers_with_balance_query.rb

@@ -12,7 +12,8 @@ class CustomersWithBalanceQuery
       joins(left_join_complete_orders).
       group("customers.id").
       select("customers.*").
-      select("#{outstanding_balance_sum} AS balance_value")
+      select("#{outstanding_balance_sum} AS balance_value").
+      select("#{available_credit} AS credit_value")
   end
 
   private
@@ -34,4 +35,21 @@ class CustomersWithBalanceQuery
   def outstanding_balance_sum
     "SUM(#{OutstandingBalanceQuery.new.statement})::float"
   end
+
+  def available_credit
+    <<~SQL.squish
+      CASE WHEN EXISTS (#{available_credit_subquery}) THEN (#{available_credit_subquery})#{' '}
+      ELSE 0.00 END
+    SQL
+  end
+
+  def available_credit_subquery
+    <<~SQL.squish
+      SELECT balance
+      FROM customer_account_transactions
+      WHERE customer_account_transactions.customer_id = customers.id
+      ORDER BY id desc
+      LIMIT 1
+    SQL
+  end
 end

app/serializers/api/admin/customer_with_balance_serializer.rb

@@ -7,14 +7,18 @@ module Api
     # columns to instance methods. This way, the `balance_value` alias on that class ends up being
     # `object.balance_value` here.
     class CustomerWithBalanceSerializer < CustomerSerializer
-      attributes :balance, :balance_status
+      attributes :balance, :balance_status, :available_credit
 
-      delegate :balance_value, to: :object
+      delegate :balance_value, :credit_value, to: :object
 
       def balance
         Spree::Money.new(balance_value, currency: CurrentConfig.get(:currency)).to_s
       end
 
+      def available_credit
+        Spree::Money.new(object.credit_value).to_s
+      end
+
       def balance_status
         if balance_value.positive?
           "credit_owed"

app/views/admin/customers/index.html.haml

@@ -73,6 +73,7 @@
             %th.bill_address{ 'ng-show' => 'columns.bill_address.visible' }=t('admin.customers.index.bill_address')
             %th.ship_address{ 'ng-show' => 'columns.ship_address.visible' }=t('admin.customers.index.ship_address')
             %th.balance{ 'ng-show' => 'columns.balance.visible' }=t('admin.customers.index.balance')
+            %th.credit{ 'ng-show' => 'columns.credit.visible' }=t('admin.customers.index.credit')
         %tbody
           %tr.customer{ 'ng-repeat' => "customer in filteredCustomers = ( customers | filter:quickSearch | orderBy: sorting.predicate:sorting.reverse ) | limitTo:customerLimit track by customer.id", 'ng-class-even' => "'even'", 'ng-class-odd' => "'odd'", :id => "c_{{customer.id}}" }
             -# %td.bulk
@@ -98,6 +99,8 @@
             %td.balance.align-center{ 'ng-show' => 'columns.balance.visible'}
               %span.state.white-space-nowrap{ 'ng-class' => 'customer.balance_status', 'ng-bind' => 'displayBalanceStatus(customer)' }
               %span{ 'ng-bind' => '::customer.balance' }
+            %td.balance.align-center{ 'ng-show' => 'columns.credit.visible'}
+              %span{ 'ng-bind' => '::customer.available_credit' }
             %td.actions
               %a{ 'ng-click' => "deleteCustomer(customer)", :class => "delete-customer icon-trash no-text" }
 

config/locales/en.yml

@@ -877,6 +877,7 @@ en:
         bill_address: "Billing Address"
         ship_address: "Shipping Address"
         balance: "Balance"
+        credit: "Available Credit"
         update_address_success: "Address updated successfully."
         update_address_error: "Sorry! Please input all of the required fields!"
         edit_bill_address: "Edit Billing Address"

lib/open_food_network/column_preference_defaults.rb

@@ -36,7 +36,8 @@ module OpenFoodNetwork
         tags: { name: I18n.t("admin.tags"), visible: true },
         bill_address: { name: I18n.t("#{node}.bill_address"), visible: true },
         ship_address: { name: I18n.t("#{node}.ship_address"), visible: true },
-        balance: { name: I18n.t("#{node}.balance"), visible: true }
+        balance: { name: I18n.t("#{node}.balance"), visible: true },
+        credit: { name: I18n.t("#{node}.credit"), visible: true }
       }
     end
 

spec/queries/customers_with_balance_query_spec.rb

@@ -210,5 +210,32 @@ RSpec.describe CustomersWithBalanceQuery do
         expect(customer.balance_value).to eq(0)
       end
     end
+
+    context "with customer payments" do
+      # TODO should not be needed, need to add this to seed somehow
+      let!(:payment_method) {
+        create(
+          :payment_method,
+          name: CustomerAccountTransaction::DEFAULT_PAYMENT_METHOD_NAME,
+          distributors: [customer.enterprise]
+        )
+      }
+
+      it 'returns the customer available credit' do
+        create(:customer_account_transaction, customer:, amount: 10.00)
+        create(:customer_account_transaction, customer:, amount: -2.00)
+        create(:customer_account_transaction, customer:, amount: 5.00)
+
+        customer_result = result.first
+        expect(customer_result.credit_value).to eq(13.00)
+      end
+    end
+
+    context "with no customer payments" do
+      it 'returns 0 for the customer available credit' do
+        customer_result = result.first
+        expect(customer_result.credit_value).to eq(0.00)
+      end
+    end
   end
 end

spec/serializers/api/admin/customer_with_balance_serializer_spec.rb

@@ -16,6 +16,19 @@ RSpec.describe Api::Admin::CustomerWithBalanceSerializer do
     end
   end
 
+  describe '#available_credit' do
+    let(:customer) { double(Customer, credit_value: 5.3) }
+    let(:money) { instance_double(Spree::Money, to_s: "$5.30") }
+
+    before do
+      allow(Spree::Money).to receive(:new).with(5.3) { money }
+    end
+
+    it 'returns the available_credit as a money amount' do
+      expect(serialized_customer.available_credit).to eq("$5.30")
+    end
+  end
+
   describe '#balance_status' do
     context 'when the balance_value is positive' do
       let(:customer) { double(Customer, balance_value: 1) }