feat(pay-v2): P8 Task3 订阅创建 + 首期激活(subscription.created)+ 端点

internal/handler/gateway.go

@@ -62,6 +62,39 @@ func (h *GatewayHandler) CreateOrder(c *gin.Context) {
 	util.RespondSuccess(c, res)
 }
 
+// CreateSubscription POST /api/v2/subscriptions —— 建订阅,返回 {sub_id, order_no, session:{render_type, payload}}。
+// biz_system 非空 → 校验 HMAC 签名(复用 v1 verifyBizSign,与 CreateOrder 同惯例)。
+func (h *GatewayHandler) CreateSubscription(c *gin.Context) {
+	raw, err := io.ReadAll(http.MaxBytesReader(c.Writer, c.Request.Body, maxOrderBodyBytes))
+	if err != nil {
+		util.RespondError(c, http.StatusBadRequest, "bad_request", "请求体过大或读取失败")
+		return
+	}
+	var req createV2Request
+	if err := json.Unmarshal(raw, &req); err != nil {
+		util.RespondError(c, http.StatusBadRequest, "bad_request", "参数格式错误")
+		return
+	}
+	if req.SKU == "" || req.Method == "" {
+		util.RespondError(c, http.StatusBadRequest, "bad_request", "缺少 sku 或 method")
+		return
+	}
+	if req.BizSystem != "" {
+		if err := verifyBizSign(c, req.BizSystem, raw); err != nil {
+			util.RespondError(c, http.StatusUnauthorized, "unauthorized", err.Error())
+			return
+		}
+	}
+	res, err := h.g.CreateSubscription(c.Request.Context(), gateway.CreateSubscriptionInput{
+		SKU: req.SKU, Method: req.Method, BizSystem: req.BizSystem, BizRef: req.BizRef, ReturnURL: req.ReturnURL,
+	})
+	if err != nil {
+		h.writeCreateErr(c, "建订阅", req.Method, err)
+		return
+	}
+	util.RespondSuccess(c, res)
+}
+
 // GetStatus GET /api/v2/orders/:order_no
 func (h *GatewayHandler) GetStatus(c *gin.Context) {
 	v, err := h.g.GetOrder(c.Param("order_no"))
@@ -158,6 +191,8 @@ func (h *GatewayHandler) writeCreateErr(c *gin.Context, action, method string, e
 		util.RespondError(c, http.StatusConflict, "currency_mismatch", "该支付方式结算币种与订单不符,请换一种支付方式")
 	case errors.Is(err, gateway.ErrNoSettleCurrency):
 		util.RespondError(c, http.StatusServiceUnavailable, "no_settle_currency", "该支付方式配置不完整,暂不可用")
+	case errors.Is(err, provider.ErrNotSupported):
+		util.RespondError(c, http.StatusBadRequest, "method_not_recurring", "该支付方式不支持订阅")
 	default:
 		log.Printf("[v2 order] %s失败 method=%s: %v", action, method, err)
 		util.RespondError(c, http.StatusInternalServerError, "create_failed", action+"失败,请稍后重试")