api: add coupon support (#289)

api/api.go

@@ -255,6 +255,7 @@ func (h *Handler) serveSubscribe(w http.ResponseWriter, r *http.Request) error {
 				Effective:    p.Effective,
 				Features:     fs,
 				AutomaticTax: sr.Tax.Automatic,
+				Coupon:       p.Coupon,
 			})
 		}
 	}
@@ -349,6 +350,7 @@ func (h *Handler) servePhase(w http.ResponseWriter, r *http.Request) error {
 					Automatic: p.AutomaticTax,
 				},
 				Current: apitypes.Period(s.Current),
+				Coupon:  p.Coupon,
 			})
 		}
 	}

api/api_test.go

@@ -29,7 +29,25 @@ var (
 	mpfs = refs.MustParseFeaturePlans
 )
 
-func newTestClient(t *testing.T) *tier.Client {
+type testClient struct {
+	t *testing.T
+	*tier.Client
+	cc *control.Client
+}
+
+func (tc *testClient) createCoupon(ctx context.Context, code string) {
+	tc.t.Helper()
+	var f stripe.Form
+	f.Set("amount_off", 1)
+	f.Set("currency", "usd")
+	f.Set("duration", "once")
+	f.Set("id", code)
+	if err := tc.cc.Stripe.Do(ctx, "POST", "/v1/coupons", f, nil); err != nil {
+		tc.t.Fatal(err)
+	}
+}
+
+func newTestClient(t *testing.T) *testClient {
 	sc := stroke.Client(t)
 	sc = stroke.WithAccount(t, sc)
 	cc := &control.Client{
@@ -45,7 +63,7 @@ func newTestClient(t *testing.T) *tier.Client {
 		BaseURL:    s.URL,
 		HTTPClient: s.Client(),
 	}
-	return tc
+	return &testClient{t, tc, cc}
 }
 
 func newTestClientWithStripe(t *testing.T, fakeStripe http.HandlerFunc) *tier.Client {
@@ -418,6 +436,8 @@ func TestPhase(t *testing.T) {
 		t.Fatal(err)
 	}
 
+	tc.createCoupon(ctx, "coupon_test")
+
 	cases := []struct {
 		phases []tier.Phase
 		want   apitypes.PhaseResponse
@@ -426,6 +446,7 @@ func TestPhase(t *testing.T) {
 			phases: []tier.Phase{{
 				Trial:    true,
 				Features: []string{"plan:test@0"},
+				Coupon:   "coupon_test",
 			}, {
 				Effective: now.AddDate(0, 0, 14),
 				Trial:     false,
@@ -437,6 +458,7 @@ func TestPhase(t *testing.T) {
 				Features:  mpfs("feature:x@plan:test@0"),
 				Plans:     mpps("plan:test@0"),
 				Trial:     true,
+				Coupon:    "coupon_test",
 			},
 		},
 		{

api/apitypes/apitypes.go

@@ -24,6 +24,7 @@ type Phase struct {
 	Trial     bool      `json:"trial,omitempty"`
 	Effective time.Time `json:"effective,omitempty"`
 	Features  []string  `json:"features,omitempty"`
+	Coupon    string    `json:"coupon,omitempty"`
 }
 
 type Taxation struct {
@@ -49,6 +50,7 @@ type PhaseResponse struct {
 	Trial     bool               `json:"trial,omitempty"`
 	Tax       Taxation           `json:"tax,omitempty"`
 	Current   Period             `json:"current,omitempty"`
+	Coupon    string             `json:"coupon,omitempty"`
 }
 
 func (pr PhaseResponse) MarshalJSON() ([]byte, error) {
@@ -59,12 +61,14 @@ func (pr PhaseResponse) MarshalJSON() ([]byte, error) {
 		End       any `json:"end,omitempty"`
 		Current   any `json:"current,omitempty"`
 		Tax       any `json:"tax,omitempty"`
+		Coupon    any `json:"coupon,omitempty"`
 	}{
 		Alias:     (*Alias)(&pr),
 		Effective: nilIfZero(pr.Effective),
 		End:       nilIfZero(pr.End),
 		Current:   nilIfZero(pr.Current),
 		Tax:       nilIfZero(pr.Tax),
+		Coupon:    nilIfZero(pr.Coupon),
 	})
 }
 

control/schedule.go

@@ -87,6 +87,8 @@ type Phase struct {
 	Plans []refs.Plan
 
 	AutomaticTax bool
+
+	Coupon string
 }
 
 // Valid reports if the Phase is one that would be retured from the Stripe API.
@@ -117,6 +119,7 @@ type subscription struct {
 	Features     []Feature
 	AutomaticTax bool // TODO(bmizerany): cheange to tax.Applied
 	Current      Period
+	Coupon       string
 }
 
 func (c *Client) lookupSubscription(ctx context.Context, org, name string) (sub subscription, err error) {
@@ -154,6 +157,11 @@ func (c *Client) lookupSubscription(ctx context.Context, org, name string) (sub
 		} `json:"automatic_tax"`
 		CurrentPeriodStart int64 `json:"current_period_start"`
 		CurrentPeriodEnd   int64 `json:"current_period_end"`
+		Discount           struct {
+			Coupon struct {
+				ID string
+			}
+		}
 	}
 
 	// TODO(bmizerany): cache the subscription ID and looked it up
@@ -195,6 +203,7 @@ func (c *Client) lookupSubscription(ctx context.Context, org, name string) (sub
 			Effective: timeUnix(v.CurrentPeriodStart),
 			End:       timeUnix(v.CurrentPeriodEnd),
 		},
+		Coupon: v.Discount.Coupon.ID,
 	}
 	if v.TrialEnd > 0 {
 		s.TrialEnd = time.Unix(v.TrialEnd, 0)
@@ -266,6 +275,7 @@ type stripeSubSchedule struct {
 		Items    []struct {
 			Price stripePrice
 		}
+		Coupon string
 	}
 }
 
@@ -353,6 +363,8 @@ func (c *Client) lookupPhases(ctx context.Context, org string, s subscription, n
 			Trial: p.TrialEnd > 0,
 
 			AutomaticTax: s.AutomaticTax,
+
+			Coupon: p.Coupon,
 		}
 		all = append(all, p)
 		if p.Current {
@@ -403,6 +415,12 @@ func subscriptionToPhases(org string, s subscription) []Phase {
 		})
 	}
 
+	for i := range ps {
+		if ps[i].Current {
+			ps[i].Coupon = s.Coupon
+		}
+	}
+
 	return ps
 }
 
@@ -467,6 +485,9 @@ func addPhases(ctx context.Context, c *Client, f *stripe.Form, update bool, name
 
 		f.Set("phases", i, "metadata[tier.subscription]", name)
 		f.Set("phases", i, "trial", p.Trial)
+		if p.Coupon != "" {
+			f.Set("phases", i, "coupon", p.Coupon)
+		}
 
 		if i == 0 {
 			if update {