Add SAN discount for upgrades

lib/sanbase/stripe/stripe_api.ex

@@ -200,10 +200,14 @@ defmodule Sanbase.StripeApi do
 
   def upgrade_downgrade(db_subscription, plan) do
     with {:ok, params} <- get_upgrade_downgrade_subscription_params(db_subscription, plan),
+         {:ok, stripe_subscription} <- retrieve_subscription(db_subscription.stripe_id),
          # Remove coupon for free basic API subscription
-         {:ok, params} <- maybe_remove_coupon(params, db_subscription, plan),
-         {:ok, stripe_subscription} <- update_subscription(db_subscription.stripe_id, params) do
-      {:ok, stripe_subscription}
+         {:ok, params} <- maybe_remove_coupon(params, db_subscription, plan, stripe_subscription),
+         # Add SAN holder coupon if user has 1000+ SAN and no existing discount
+         {:ok, params} <- maybe_add_san_coupon(params, db_subscription, stripe_subscription),
+         {:ok, updated_stripe_subscription} <-
+           update_subscription(db_subscription.stripe_id, params) do
+      {:ok, updated_stripe_subscription}
     end
   end
 
@@ -257,24 +261,34 @@ defmodule Sanbase.StripeApi do
 
   # Helpers
 
-  defp maybe_remove_coupon(params, db_subscription, _plan) do
-    with {:ok, stripe_subscription} <- retrieve_subscription(db_subscription.stripe_id) do
-      percent_off =
-        get_in(stripe_subscription, [
-          Access.key!(:discount),
-          Access.key!(:coupon),
-          Access.key!(:percent_off)
-        ])
-
-      is_basic_plan? = fn plan_id ->
-        plan_id in Sanbase.Billing.Subscription.ProPlus.basic_api_plans()
-      end
-
-      if is_basic_plan?.(db_subscription.plan_id) and percent_off == 100.0 do
-        {:ok, Map.put(params, :coupon, nil)}
-      else
-        {:ok, params}
-      end
+  defp maybe_remove_coupon(params, db_subscription, _plan, stripe_subscription) do
+    percent_off =
+      get_in(stripe_subscription, [
+        Access.key(:discount),
+        Access.key(:coupon),
+        Access.key(:percent_off)
+      ])
+
+    is_basic_plan? = fn plan_id ->
+      plan_id in Sanbase.Billing.Subscription.ProPlus.basic_api_plans()
+    end
+
+    if is_basic_plan?.(db_subscription.plan_id) and percent_off == 100.0 do
+      {:ok, Map.put(params, :coupon, nil)}
+    else
+      {:ok, params}
+    end
+  end
+
+  defp maybe_add_san_coupon(params, db_subscription, stripe_subscription) do
+    has_discount? = not is_nil(stripe_subscription.discount)
+    user = db_subscription.user
+    san_balance = User.san_balance_or_zero(user)
+
+    if not has_discount? and san_balance >= 1000 do
+      {:ok, Map.put(params, :coupon, "SAN_HOLDER_1000")}
+    else
+      {:ok, params}
     end
   end
 

test/sanbase/billing/subscription_test.exs

@@ -126,6 +126,113 @@ defmodule Sanbase.Billing.SubscriptionTest do
     end
   end
 
+  describe "#update_subscription - SAN discount on upgrade" do
+    test "applies SAN discount when user has 1000+ SAN and no existing coupon", context do
+      user = insert(:user, email: "test@example.com", san_balance: Decimal.new(1000))
+      subscription = insert(:subscription_pro_sanbase, user: user, stripe_id: "sub_test_upgrade")
+      new_plan = context.plans.plan_pro_sanbase_yearly
+
+      stripe_sub_no_discount =
+        StripeApiTestResponse.retrieve_subscription_resp(stripe_id: "sub_test_upgrade") |> elem(1)
+
+      test_pid = self()
+
+      with_mocks([
+        {Stripe.Subscription, [],
+         [
+           retrieve: fn _stripe_id, _opts -> {:ok, stripe_sub_no_discount} end,
+           update: fn _stripe_id, params, _opts ->
+             send(test_pid, {:update_params, params})
+             StripeApiTestResponse.update_subscription_resp()
+           end
+         ]}
+      ]) do
+        {:ok, _updated} = Subscription.update_subscription(subscription, new_plan)
+
+        assert_receive {:update_params, params}
+        assert params[:coupon] == "SAN_HOLDER_1000"
+      end
+    end
+
+    test "does not apply coupon when subscription already has a discount", context do
+      user = insert(:staked_user, email: "test@example.com")
+      subscription = insert(:subscription_pro_sanbase, user: user, stripe_id: "sub_test_upgrade")
+      new_plan = context.plans.plan_pro_sanbase_yearly
+
+      stripe_sub_with_discount =
+        StripeApiTestResponse.retrieve_subscription_resp(stripe_id: "sub_test_upgrade")
+        |> elem(1)
+        |> Map.put(:discount, %{coupon: %{id: "existing_coupon", percent_off: 10}})
+
+      test_pid = self()
+
+      with_mocks([
+        {Stripe.Subscription, [],
+         [
+           retrieve: fn _stripe_id, _opts -> {:ok, stripe_sub_with_discount} end,
+           update: fn _stripe_id, params, _opts ->
+             send(test_pid, {:update_params, params})
+             StripeApiTestResponse.update_subscription_resp()
+           end
+         ]}
+      ]) do
+        {:ok, _updated} = Subscription.update_subscription(subscription, new_plan)
+
+        assert_receive {:update_params, params}
+        refute Map.has_key?(params, :coupon)
+      end
+    end
+
+    test "does not apply coupon when user has less than 1000 SAN", context do
+      user = insert(:user, email: "test@example.com", san_balance: Decimal.new(500))
+      subscription = insert(:subscription_pro_sanbase, user: user, stripe_id: "sub_test_upgrade")
+      new_plan = context.plans.plan_pro_sanbase_yearly
+
+      stripe_sub_no_discount =
+        StripeApiTestResponse.retrieve_subscription_resp(stripe_id: "sub_test_upgrade") |> elem(1)
+
+      test_pid = self()
+
+      with_mocks([
+        {Stripe.Subscription, [],
+         [
+           retrieve: fn _stripe_id, _opts -> {:ok, stripe_sub_no_discount} end,
+           update: fn _stripe_id, params, _opts ->
+             send(test_pid, {:update_params, params})
+             StripeApiTestResponse.update_subscription_resp()
+           end
+         ]}
+      ]) do
+        {:ok, _updated} = Subscription.update_subscription(subscription, new_plan)
+
+        assert_receive {:update_params, params}
+        refute Map.has_key?(params, :coupon)
+      end
+    end
+
+    test "upgrade works for user without SAN balance (no regression)", context do
+      user = insert(:user, email: "test@example.com")
+      subscription = insert(:subscription_pro_sanbase, user: user, stripe_id: "sub_test_upgrade")
+      new_plan = context.plans.plan_pro_sanbase_yearly
+
+      stripe_sub_no_discount =
+        StripeApiTestResponse.retrieve_subscription_resp(stripe_id: "sub_test_upgrade") |> elem(1)
+
+      with_mocks([
+        {Stripe.Subscription, [],
+         [
+           retrieve: fn _stripe_id, _opts -> {:ok, stripe_sub_no_discount} end,
+           update: fn _stripe_id, _params, _opts ->
+             StripeApiTestResponse.update_subscription_resp()
+           end
+         ]}
+      ]) do
+        result = Subscription.update_subscription(subscription, new_plan)
+        assert {:ok, _updated} = result
+      end
+    end
+  end
+
   describe "#sync_subscription_with_stripe" do
     setup(context) do
       stripe_base_subscription =