feat(payment): 新增 Creem 支付接入

backend/internal/handler/payment_webhook_handler.go

@@ -67,6 +67,12 @@ func (h *PaymentWebhookHandler) AirwallexWebhook(c *gin.Context) {
 	h.handleNotify(c, payment.TypeAirwallex)
 }
 
+// CreemWebhook 处理 Creem Webhook 事件。
+// POST /api/v1/payment/webhook/creem
+func (h *PaymentWebhookHandler) CreemWebhook(c *gin.Context) {
+	h.handleNotify(c, payment.TypeCreem)
+}
+
 // handleNotify is the shared logic for all provider webhook handlers.
 func (h *PaymentWebhookHandler) handleNotify(c *gin.Context, providerKey string) {
 	var rawBody string
@@ -172,6 +178,21 @@ func extractOutTradeNo(rawBody, providerKey string) string {
 		if err := json.Unmarshal([]byte(rawBody), &payload); err == nil {
 			return strings.TrimSpace(payload.Data.Object.MerchantOrderID)
 		}
+	case payment.TypeCreem:
+		var payload struct {
+			Object struct {
+				RequestID string `json:"request_id"`
+			} `json:"object"`
+			Data struct {
+				RequestID string `json:"request_id"`
+			} `json:"data"`
+		}
+		if err := json.Unmarshal([]byte(rawBody), &payload); err == nil {
+			if id := strings.TrimSpace(payload.Object.RequestID); id != "" {
+				return id
+			}
+			return strings.TrimSpace(payload.Data.RequestID)
+		}
 	}
 	// For other providers (Stripe, Alipay direct, WxPay direct), the registry
 	// typically has only one instance, so no instance lookup is needed.
@@ -214,12 +235,12 @@ const (
 
 // writeSuccessResponse 返回各支付服务商要求的成功响应。
 // 微信支付需要 JSON {"code":"SUCCESS","message":"成功"}；
-// Stripe 和空中云汇接受空 200，其它服务商接受纯文本 "success"。
+// Stripe、空中云汇和 Creem 接受空 200，其它服务商接受纯文本 "success"。
 func writeSuccessResponse(c *gin.Context, providerKey string) {
 	switch providerKey {
 	case payment.TypeWxpay:
 		c.JSON(http.StatusOK, wxpaySuccessResponse{Code: wxpaySuccessCode, Message: wxpaySuccessMessage})
-	case payment.TypeStripe, payment.TypeAirwallex:
+	case payment.TypeStripe, payment.TypeAirwallex, payment.TypeCreem:
 		c.String(http.StatusOK, "")
 	default:
 		c.String(http.StatusOK, "success")

backend/internal/handler/payment_webhook_handler_test.go

@@ -54,6 +54,13 @@ func TestWriteSuccessResponse(t *testing.T) {
 			wantContentType: "text/plain",
 			wantBody:        "",
 		},
+		{
+			name:            "creem returns empty 200",
+			providerKey:     payment.TypeCreem,
+			wantCode:        http.StatusOK,
+			wantContentType: "text/plain",
+			wantBody:        "",
+		},
 		{
 			name:            "easypay returns plain text success",
 			providerKey:     "easypay",
@@ -178,6 +185,18 @@ func TestExtractOutTradeNo(t *testing.T) {
 			rawBody:     `{"name":"payment_intent.succeeded","data":{"object":{"merchant_order_id":"sub2_awx_123"}}}`,
 			want:        "sub2_awx_123",
 		},
+		{
+			name:        "creem checkout.completed payload",
+			providerKey: payment.TypeCreem,
+			rawBody:     `{"eventType":"checkout.completed","object":{"id":"ch_1","request_id":"sub2_creem_1"}}`,
+			want:        "sub2_creem_1",
+		},
+		{
+			name:        "creem type/data envelope",
+			providerKey: payment.TypeCreem,
+			rawBody:     `{"type":"checkout.completed","data":{"id":"ch_1","request_id":"sub2_creem_2"}}`,
+			want:        "sub2_creem_2",
+		},
 	}
 
 	for _, tt := range tests {

backend/internal/payment/currency.go

@@ -64,6 +64,22 @@ func NormalizePaymentCurrency(raw string) (string, error) {
 	return currency, nil
 }
 
+// CreemDefaultCurrency 是 Creem 实例未配置币种时使用的币种。Creem 商品只支持 USD 和 EUR，
+// 不能沿用全局默认的 CNY。
+const CreemDefaultCurrency = "USD"
+
+// NormalizeCreemCurrency 校验 Creem 实例币种，空值回落到 USD。
+func NormalizeCreemCurrency(raw string) (string, error) {
+	currency := strings.ToUpper(strings.TrimSpace(raw))
+	if currency == "" {
+		return CreemDefaultCurrency, nil
+	}
+	if currency != "USD" && currency != "EUR" {
+		return "", fmt.Errorf("creem currency must be USD or EUR")
+	}
+	return currency, nil
+}
+
 func CurrencyMinorUnit(currency string) int {
 	return paymentCurrencyAmountUnitFor(currency).apiMinorUnit
 }