feat(payment): support placeholder orders for GMPay and EPay

src/model/dao/mdb_table_init.go

@@ -163,9 +163,9 @@ func seedDefaultSettings() {
 	defaults := []mdb.Setting{
 		{Group: mdb.SettingGroupSystem, Key: mdb.SettingKeyAmountPrecision, Value: "2", Type: mdb.SettingTypeInt},
 		{Group: mdb.SettingGroupSystem, Key: mdb.SettingKeySystemLogLevel, Value: mdb.SettingDefaultSystemLogLevel, Type: mdb.SettingTypeString},
-		{Group: mdb.SettingGroupEpay, Key: mdb.SettingKeyEpayDefaultToken, Value: "usdt", Type: mdb.SettingTypeString},
+		{Group: mdb.SettingGroupEpay, Key: mdb.SettingKeyEpayDefaultToken, Value: "", Type: mdb.SettingTypeString},
 		{Group: mdb.SettingGroupEpay, Key: mdb.SettingKeyEpayDefaultCurrency, Value: "cny", Type: mdb.SettingTypeString},
-		{Group: mdb.SettingGroupEpay, Key: mdb.SettingKeyEpayDefaultNetwork, Value: "tron", Type: mdb.SettingTypeString},
+		{Group: mdb.SettingGroupEpay, Key: mdb.SettingKeyEpayDefaultNetwork, Value: "", Type: mdb.SettingTypeString},
 		{Group: mdb.SettingGroupOkPay, Key: mdb.SettingKeyOkPayEnabled, Value: "false", Type: mdb.SettingTypeBool},
 		{Group: mdb.SettingGroupOkPay, Key: mdb.SettingKeyOkPayAPIURL, Value: "https://api.okaypay.me/shop/", Type: mdb.SettingTypeString},
 		{Group: mdb.SettingGroupOkPay, Key: mdb.SettingKeyOkPayCallbackURL, Value: okPayCallbackURL, Type: mdb.SettingTypeString},

src/model/dao/mdb_table_init_test.go

@@ -95,6 +95,63 @@ func TestSeedDefaultSettingsIncludesSystemLogLevel(t *testing.T) {
 	}
 }
 
+func TestSeedDefaultSettingsUsesEmptyEpayTokenAndNetwork(t *testing.T) {
+	db := setupSeedSettingsTestDB(t)
+	Mdb = db
+
+	seedDefaultSettings()
+
+	rows := make(map[string]mdb.Setting)
+	for _, key := range []string{
+		mdb.SettingKeyEpayDefaultToken,
+		mdb.SettingKeyEpayDefaultCurrency,
+		mdb.SettingKeyEpayDefaultNetwork,
+	} {
+		var row mdb.Setting
+		if err := Mdb.Where("`key` = ?", key).Take(&row).Error; err != nil {
+			t.Fatalf("load %s seed: %v", key, err)
+		}
+		rows[key] = row
+	}
+	if rows[mdb.SettingKeyEpayDefaultToken].Value != "" {
+		t.Fatalf("epay.default_token seed = %q, want empty", rows[mdb.SettingKeyEpayDefaultToken].Value)
+	}
+	if rows[mdb.SettingKeyEpayDefaultNetwork].Value != "" {
+		t.Fatalf("epay.default_network seed = %q, want empty", rows[mdb.SettingKeyEpayDefaultNetwork].Value)
+	}
+	if rows[mdb.SettingKeyEpayDefaultCurrency].Value != "cny" {
+		t.Fatalf("epay.default_currency seed = %q, want cny", rows[mdb.SettingKeyEpayDefaultCurrency].Value)
+	}
+}
+
+func TestSeedDefaultSettingsDoesNotOverwriteExistingEpayDefaults(t *testing.T) {
+	db := setupSeedSettingsTestDB(t)
+	Mdb = db
+	for _, row := range []mdb.Setting{
+		{Group: mdb.SettingGroupEpay, Key: mdb.SettingKeyEpayDefaultToken, Value: "usdt", Type: mdb.SettingTypeString},
+		{Group: mdb.SettingGroupEpay, Key: mdb.SettingKeyEpayDefaultNetwork, Value: "tron", Type: mdb.SettingTypeString},
+	} {
+		if err := Mdb.Create(&row).Error; err != nil {
+			t.Fatalf("precreate %s: %v", row.Key, err)
+		}
+	}
+
+	seedDefaultSettings()
+
+	for key, want := range map[string]string{
+		mdb.SettingKeyEpayDefaultToken:   "usdt",
+		mdb.SettingKeyEpayDefaultNetwork: "tron",
+	} {
+		var row mdb.Setting
+		if err := Mdb.Where("`key` = ?", key).Take(&row).Error; err != nil {
+			t.Fatalf("load %s seed: %v", key, err)
+		}
+		if row.Value != want {
+			t.Fatalf("%s value = %q, want existing %q", key, row.Value, want)
+		}
+	}
+}
+
 func TestSeedDefaultSettingsDoesNotOverwriteSystemLogLevel(t *testing.T) {
 	db := setupSeedSettingsTestDB(t)
 	Mdb = db

src/model/data/order_admin_data.go

@@ -105,12 +105,12 @@ func CountOrdersByStatus() (map[int]int64, error) {
 	return out, nil
 }
 
-// CloseOrderManually transitions a pending order to expired. Only
-// touches rows currently in StatusWaitPay so idempotent / safe.
+// CloseOrderManually transitions a pending order to expired. It covers both
+// payable orders and placeholder orders waiting for token/network selection.
 func CloseOrderManually(tradeID string) (bool, error) {
 	result := dao.Mdb.Model(&mdb.Orders{}).
 		Where("trade_id = ?", tradeID).
-		Where("status = ?", mdb.StatusWaitPay).
+		Where("status IN ?", []int{mdb.StatusWaitPay, mdb.StatusWaitSelect}).
 		Update("status", mdb.StatusExpired)
 	return result.RowsAffected > 0, result.Error
 }

src/model/data/order_data.go

@@ -209,7 +209,7 @@ func SaveCallBackOrdersResp(order *mdb.Orders) error {
 func UpdateOrderIsExpirationById(id uint64, expirationCutoff time.Time) (bool, error) {
 	result := dao.Mdb.Model(mdb.Orders{}).
 		Where("id = ?", id).
-		Where("status = ?", mdb.StatusWaitPay).
+		Where("status IN ?", []int{mdb.StatusWaitPay, mdb.StatusWaitSelect}).
 		Where("created_at <= ?", expirationCutoff).
 		Update("status", mdb.StatusExpired)
 	return result.RowsAffected > 0, result.Error
@@ -225,6 +225,15 @@ func CountActiveSubOrders(parentTradeId string) (int64, error) {
 	return count, err
 }
 
+// CountSubOrders counts all sub-orders ever created under a parent.
+func CountSubOrders(parentTradeId string) (int64, error) {
+	var count int64
+	err := dao.Mdb.Model(&mdb.Orders{}).
+		Where("parent_trade_id = ?", parentTradeId).
+		Count(&count).Error
+	return count, err
+}
+
 // GetSubOrderByTokenNetwork finds an existing active sub-order matching token+network under a parent.
 func GetSubOrderByTokenNetwork(parentTradeId string, token string, network string) (*mdb.Orders, error) {
 	order := new(mdb.Orders)
@@ -288,6 +297,61 @@ func MarkOrderSelected(tradeId string) error {
 		Update("is_selected", true).Error
 }
 
+// CompleteWaitSelectOrder fills a placeholder order with concrete chain fields
+// and makes it payable. It only updates status=WaitSelect rows so concurrent
+// switch-network attempts cannot overwrite a payable order.
+func CompleteWaitSelectOrder(tradeID string, network string, token string, receiveAddress string, actualAmount float64) (bool, error) {
+	result := dao.Mdb.Model(&mdb.Orders{}).
+		Where("trade_id = ?", tradeID).
+		Where("status = ?", mdb.StatusWaitSelect).
+		Updates(map[string]interface{}{
+			"status":          mdb.StatusWaitPay,
+			"network":         strings.ToLower(strings.TrimSpace(network)),
+			"token":           strings.ToUpper(strings.TrimSpace(token)),
+			"receive_address": receiveAddress,
+			"actual_amount":   actualAmount,
+			"is_selected":     false,
+			"created_at":      time.Now(),
+		})
+	return result.RowsAffected > 0, result.Error
+}
+
+// CompleteWaitSelectOkPayOrderWithTransaction converts a placeholder parent
+// directly into an OkPay order. It intentionally does not create a local chain
+// lock because OkPay owns the hosted payment target.
+func CompleteWaitSelectOkPayOrderWithTransaction(tx *gorm.DB, tradeID string, token string, actualAmount float64) (bool, error) {
+	result := tx.Model(&mdb.Orders{}).
+		Where("trade_id = ?", tradeID).
+		Where("status = ?", mdb.StatusWaitSelect).
+		Updates(map[string]interface{}{
+			"status":          mdb.StatusWaitPay,
+			"network":         mdb.PaymentProviderOkPay,
+			"token":           strings.ToUpper(strings.TrimSpace(token)),
+			"receive_address": "OKPAY",
+			"actual_amount":   actualAmount,
+			"is_selected":     false,
+			"pay_provider":    mdb.PaymentProviderOkPay,
+			"created_at":      time.Now(),
+		})
+	return result.RowsAffected > 0, result.Error
+}
+
+// MarkProviderSwitchParentSelectedWithTransaction marks a switch-network parent
+// as selected for a hosted payment provider. It intentionally does not fill
+// chain fields or create a transaction lock; the provider child order carries
+// the concrete payment target.
+func MarkProviderSwitchParentSelectedWithTransaction(tx *gorm.DB, tradeID string) (bool, error) {
+	result := tx.Model(&mdb.Orders{}).
+		Where("trade_id = ?", tradeID).
+		Where("status IN ?", []int{mdb.StatusWaitPay, mdb.StatusWaitSelect}).
+		Updates(map[string]interface{}{
+			"status":      mdb.StatusWaitPay,
+			"is_selected": true,
+			"created_at":  time.Now(),
+		})
+	return result.RowsAffected > 0, result.Error
+}
+
 // ExpireOrderByTradeID marks a waiting order as expired. Used to retire failed
 // child-order attempts that should not remain selectable/reusable.
 func ExpireOrderByTradeID(tradeId string) error {

src/model/data/provider_order_data.go

@@ -4,6 +4,7 @@ import (
 	"github.com/GMWalletApp/epusdt/model/dao"
 	"github.com/GMWalletApp/epusdt/model/mdb"
 	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
 )
 
 func GetProviderOrderByTradeIDAndProvider(tradeID string, provider string) (*mdb.ProviderOrder, error) {
@@ -20,8 +21,27 @@ func CreateProviderOrderWithTransaction(tx *gorm.DB, row *mdb.ProviderOrder) err
 	return tx.Model(row).Create(row).Error
 }
 
+func UpsertProviderOrderCreatingWithTransaction(tx *gorm.DB, row *mdb.ProviderOrder) error {
+	return tx.Clauses(clause.OnConflict{
+		Columns: []clause.Column{{Name: "trade_id"}, {Name: "provider"}},
+		DoUpdates: clause.AssignmentColumns([]string{
+			"provider_order_id",
+			"pay_url",
+			"amount",
+			"coin",
+			"status",
+			"notify_raw",
+			"updated_at",
+		}),
+	}).Create(row).Error
+}
+
 func UpdateProviderOrderCreated(tradeID string, provider string, providerOrderID string, payURL string) error {
-	return dao.Mdb.Model(&mdb.ProviderOrder{}).
+	return UpdateProviderOrderCreatedWithTransaction(dao.Mdb, tradeID, provider, providerOrderID, payURL)
+}
+
+func UpdateProviderOrderCreatedWithTransaction(tx *gorm.DB, tradeID string, provider string, providerOrderID string, payURL string) error {
+	return tx.Model(&mdb.ProviderOrder{}).
 		Where("trade_id = ?", tradeID).
 		Where("provider = ?", provider).
 		Updates(map[string]interface{}{

src/model/mdb/orders_mdb.go

@@ -1,15 +1,24 @@
 package mdb
 
 const (
-	StatusWaitPay     = 1
-	StatusPaySuccess  = 2
-	StatusExpired     = 3
+	StatusWaitPay    = 1
+	StatusPaySuccess = 2
+	StatusExpired    = 3
+	// StatusWaitSelect is a placeholder order waiting for the payer to choose
+	// token+network or a hosted provider such as OkPay. It is not payable until
+	// switch-network moves it to StatusWaitPay.
+	StatusWaitSelect  = 4
 	CallBackConfirmOk = 1
 	CallBackConfirmNo = 2
 )
 
 const (
+	// PaymentTypeEpay is the normalized special payment_type value. Orders
+	// matching it case-insensitively use the legacy EPay callback shape.
 	PaymentTypeEpay = "Epay"
+	// PaymentTypeGmpay is the normalized default for GMPay-created orders.
+	// It uses the default GMPay JSON callback shape.
+	PaymentTypeGmpay = "Gmpay"
 )
 
 const (
@@ -19,9 +28,10 @@ const (
 	// PaymentProviderOkPay means this concrete order record is settled through
 	// the third-party OkayPay/OkPay hosted checkout flow.
 	//
-	// In the current design this is typically used by a switch-network-created
-	// child order, while the parent order keeps its original merchant-facing
-	// semantics and callback behavior.
+	// It can be used by a status=4 parent completed in place on first
+	// switch-network, or by a switch-network-created child order after the
+	// parent is already concrete. Merchant callback shape is still controlled by
+	// PaymentType, not by this provider value.
 	PaymentProviderOkPay = "okpay"
 )
 
@@ -36,21 +46,23 @@ type Orders struct {
 	ReceiveAddress     string  `gorm:"column:receive_address" json:"receive_address" example:"TTestTronAddress001"`
 	Token              string  `gorm:"column:token" json:"token" example:"USDT"`
 	Network            string  `gorm:"column:network" json:"network" example:"tron"`
-	// 订单状态 1=等待支付 2=支付成功 3=已过期
-	Status      int    `gorm:"column:status;default:1" json:"status" enums:"1,2,3" example:"1"`
+	// 订单状态 1=等待支付 2=支付成功 3=已过期 4=等待选择支付网络/币种
+	Status      int    `gorm:"column:status;default:1" json:"status" enums:"1,2,3,4" example:"1"`
 	NotifyUrl   string `gorm:"column:notify_url" json:"notify_url" example:"https://example.com/notify"`
 	RedirectUrl string `gorm:"column:redirect_url" json:"redirect_url" example:"https://example.com/success"`
 	Name        string `gorm:"column:name" json:"name" example:"VIP月卡"`
 	CallbackNum int    `gorm:"column:callback_num;default:0" json:"callback_num" example:"0"`
 	// 回调确认状态 1=回调成功 2=未回调/回调失败
-	CallBackConfirm int    `gorm:"column:callback_confirm;default:2" json:"callback_confirm" enums:"1,2" example:"2"`
-	IsSelected      bool   `gorm:"column:is_selected;default:false" json:"is_selected" example:"false"`
-	PaymentType     string `gorm:"column:payment_type" json:"payment_type" example:"Epay"`
+	CallBackConfirm int  `gorm:"column:callback_confirm;default:2" json:"callback_confirm" enums:"1,2" example:"2"`
+	IsSelected      bool `gorm:"column:is_selected;default:false" json:"is_selected" example:"false"`
+	// PaymentType is not a channel selector. "Epay" changes callback format
+	// to legacy EPay case-insensitively; "Gmpay" uses GMPay JSON.
+	PaymentType string `gorm:"column:payment_type" json:"payment_type" example:"Epay"`
 	// PayProvider identifies how this specific order row is collected.
 	//
 	// Semantics:
-	//   - parent orders and regular chain child orders use on_chain
-	//   - third-party hosted checkout child orders use their provider name
+	//   - chain parent orders and regular chain child orders use on_chain
+	//   - third-party hosted checkout rows use their provider name
 	//     (for example okpay)
 	//
 	// Existing rows default to on_chain for backward compatibility so upgrades

src/model/mdb/provider_order.go

@@ -9,8 +9,8 @@ const (
 )
 
 // ProviderOrder stores provider-specific checkout data for one internal order
-// row. For OkPay this is expected to bind to the concrete child order created
-// by switch-network, not to the parent merchant order.
+// row. For OkPay this can bind either to a status=4 parent completed in place
+// or to a concrete child order created by later switch-network calls.
 //
 // Binding rules:
 //   - trade_id always points to orders.trade_id

src/model/request/order_request.go

@@ -6,14 +6,18 @@ import "github.com/gookit/validate"
 type CreateTransactionRequest struct {
 	OrderId     string  `json:"order_id" form:"order_id" validate:"required|maxLen:32" example:"ORD20260416001"`
 	Currency    string  `json:"currency" form:"currency" validate:"required" example:"cny"` // 法币 如：cny
-	Token       string  `json:"token" form:"token" validate:"required" example:"usdt"`      // 币种 如：usdt、ton
-	Network     string  `json:"network" form:"network" validate:"required" example:"tron"`  // 网络 如：ton、tron
+	Token       string  `json:"token" form:"token" example:"usdt"`                          // 币种 如：usdt、ton；可与 network 同时缺省创建占位订单
+	Network     string  `json:"network" form:"network" example:"tron"`                      // 网络 如：ton、tron；可与 token 同时缺省创建占位订单
 	Amount      float64 `json:"amount" form:"amount" validate:"required|isFloat|gt:0.01" example:"100.00"`
 	NotifyUrl   string  `json:"notify_url" form:"notify_url" validate:"required" example:"https://example.com/notify"`
 	Signature   string  `json:"signature" form:"signature" validate:"required" example:"a1b2c3d4e5f6..."`
 	RedirectUrl string  `json:"redirect_url" form:"redirect_url" example:"https://example.com/success"`
 	Name        string  `json:"name" form:"name" example:"VIP月卡"`
-	PaymentType string  `json:"payment_type" form:"payment_type" example:"Epay"`
+	// PaymentType is a compatibility flag, not a gateway selector. Only
+	// "Epay" (case-insensitive) switches callback format to legacy EPay;
+	// empty or any other value is stored as "Gmpay" and uses GMPay JSON.
+	// It is optional for GMPay, but must be included in the signature when sent.
+	PaymentType string `json:"payment_type" form:"payment_type" example:"Epay"`
 }
 
 func (r CreateTransactionRequest) Translates() map[string]string {

src/model/response/order_response.go

@@ -9,6 +9,7 @@ type CreateTransactionResponse struct {
 	ActualAmount   float64 `json:"actual_amount" example:"14.2857"`                                                 //  订单实际需要支付的金额，按 system.amount_precision 保留小数
 	ReceiveAddress string  `json:"receive_address" example:"TTestTronAddress001"`                                   //  收款钱包地址
 	Token          string  `json:"token" example:"USDT"`                                                            // 所属币种 TRX USDT......
+	Status         int     `json:"status" enums:"1,2,3,4" example:"1"`                                              // 订单状态 1=等待支付 2=支付成功 3=已过期 4=等待选择支付网络/币种
 	ExpirationTime int64   `json:"expiration_time" example:"1713264600"`                                            // 过期时间 时间戳
 	PaymentUrl     string  `json:"payment_url" example:"https://pay.example.com/checkout/3nQ9pL2xV7sK1mR8cT4yB_aZ"` // 收银台地址
 }

src/model/response/pay_response.go

@@ -1,24 +1,26 @@
 package response
 
 type CheckoutCounterResponse struct {
-	TradeId        string  `json:"trade_id" example:"3nQ9pL2xV7sK1mR8cT4yB_aZ"`   //  epusdt订单号
-	Amount         float64 `json:"amount" example:"100.0000"`                     //  订单金额，按 system.amount_precision 保留小数 法币金额
-	ActualAmount   float64 `json:"actual_amount" example:"14.2857"`               //  订单实际需要支付的金额，按 system.amount_precision 保留小数 加密货币金额
-	Token          string  `json:"token" example:"USDT"`                          //  所属币种 TRX USDT......
-	Currency       string  `json:"currency" example:"CNY"`                        //  法币币种 CNY USD ...
-	ReceiveAddress string  `json:"receive_address" example:"TTestTronAddress001"` //  收款钱包地址
-	Network        string  `json:"network" example:"tron"`                        //  网络 TRON ETH ...
-	ExpirationTime int64   `json:"expiration_time" example:"1713264600"`          // 过期时间 时间戳
+	TradeId        string  `json:"trade_id" example:"3nQ9pL2xV7sK1mR8cT4yB_aZ"`     //  epusdt订单号
+	Amount         float64 `json:"amount" example:"100.0000"`                       //  订单金额，按 system.amount_precision 保留小数 法币金额
+	ActualAmount   float64 `json:"actual_amount" example:"14.2857"`                 //  订单实际需要支付的金额；status=4 占位订单返回 0
+	Token          string  `json:"token" example:"USDT"`                            //  所属币种；status=4 占位订单为空
+	Currency       string  `json:"currency" example:"CNY"`                          //  法币币种 CNY USD ...
+	ReceiveAddress string  `json:"receive_address" example:"TTestTronAddress001"`   //  收款钱包地址；status=4 占位订单为空
+	Network        string  `json:"network" example:"tron"`                          //  网络 TRON ETH；status=4 占位订单为空
+	Status         int     `json:"status" enums:"1,2,3,4" example:"1"`              // 订单状态 1=等待支付 2=支付成功 3=已过期 4=等待选择支付网络/币种；status=4 时前端应引导选择链上 token/network 或 OkPay
+	PaymentType    string  `json:"payment_type" enums:"gmpay,epay" example:"gmpay"` // 支付接入类型；底层 Epay/Gmpay 转为小写 epay/gmpay 返回
+	ExpirationTime int64   `json:"expiration_time" example:"1713264600"`            // 过期时间 时间戳
 	RedirectUrl    string  `json:"redirect_url" example:"https://example.com/success"`
-	PaymentUrl     string  `json:"payment_url" example:"https://pay.example.com/checkout/3nQ9pL2xV7sK1mR8cT4yB_aZ"` // 支付链接；链上订单通常为本地收银台，OkPay 子订单为第三方 payLink
+	PaymentUrl     string  `json:"payment_url" example:"https://pay.example.com/checkout/3nQ9pL2xV7sK1mR8cT4yB_aZ"` // 支付链接；链上订单为空，OkPay 订单为第三方 payLink
 	CreatedAt      int64   `json:"created_at" example:"1713264000"`                                                 // 订单创建时间 时间戳
-	IsSelected     bool    `json:"is_selected" example:"false"`
+	IsSelected     bool    `json:"is_selected" example:"false"`                                                     // 是否已选择当前支付方式；status=4 占位订单和刚补全的占位父单为 false
 }
 
 type CheckStatusResponse struct {
 	TradeId string `json:"trade_id" example:"3nQ9pL2xV7sK1mR8cT4yB_aZ"` //  epusdt订单号
-	// 订单状态 1=等待支付 2=支付成功 3=已过期
-	Status int `json:"status" enums:"1,2,3" example:"1"`
+	// 订单状态 1=等待支付 2=支付成功 3=已过期 4=等待选择支付网络/币种
+	Status int `json:"status" enums:"1,2,3,4" example:"1"`
 }
 
 type ManualPaymentResponse struct {

src/model/response/support_response.go

@@ -7,9 +7,9 @@ type NetworkTokenSupport struct {
 }
 
 type EpayPublicConfig struct {
-	DefaultToken    string `json:"default_token" example:"usdt"`
-	DefaultCurrency string `json:"default_currency" example:"cny"`
-	DefaultNetwork  string `json:"default_network" example:"tron"`
+	DefaultToken    string `json:"default_token" example:""`       // EPay default token; empty means submit.php can create a status=4 placeholder when request token/network are also absent.
+	DefaultCurrency string `json:"default_currency" example:"cny"` // EPay default fiat currency; falls back to cny when unset.
+	DefaultNetwork  string `json:"default_network" example:""`     // EPay default network; empty means submit.php can create a status=4 placeholder when request token/network are also absent.
 }
 
 type SitePublicConfig struct {

src/model/service/okpay_service_test.go

@@ -102,6 +102,79 @@ func TestHandleOkPayNotifySendsPaymentNotificationOnSuccess(t *testing.T) {
 	}
 }
 
+func TestHandleOkPayNotifySettlesPlaceholderParent(t *testing.T) {
+	cleanup := testutil.SetupTestDatabases(t)
+	defer cleanup()
+
+	const (
+		shopID          = "okpay-shop-placeholder"
+		shopToken       = "okpay-shop-placeholder-token"
+		parentTradeID   = "okpay-placeholder-parent-001"
+		providerOrderID = "okpay-placeholder-provider-001"
+	)
+
+	if err := data.SetSetting(mdb.SettingGroupOkPay, mdb.SettingKeyOkPayShopID, shopID, mdb.SettingTypeString); err != nil {
+		t.Fatalf("seed okpay shop id: %v", err)
+	}
+	if err := data.SetSetting(mdb.SettingGroupOkPay, mdb.SettingKeyOkPayShopToken, shopToken, mdb.SettingTypeString); err != nil {
+		t.Fatalf("seed okpay shop token: %v", err)
+	}
+
+	parent := &mdb.Orders{
+		TradeId:        parentTradeID,
+		OrderId:        "merchant-okpay-placeholder-parent-001",
+		Amount:         1,
+		Currency:       "CNY",
+		ActualAmount:   0.15,
+		ReceiveAddress: "OKPAY",
+		Token:          "USDT",
+		Network:        mdb.PaymentProviderOkPay,
+		Status:         mdb.StatusWaitPay,
+		IsSelected:     true,
+		PaymentType:    mdb.PaymentTypeGmpay,
+		PayProvider:    mdb.PaymentProviderOkPay,
+	}
+	if err := dao.Mdb.Create(parent).Error; err != nil {
+		t.Fatalf("seed parent order: %v", err)
+	}
+	if err := dao.Mdb.Create(&mdb.ProviderOrder{
+		TradeId:         parentTradeID,
+		Provider:        mdb.PaymentProviderOkPay,
+		ProviderOrderID: providerOrderID,
+		Amount:          0.15,
+		Coin:            "USDT",
+		Status:          mdb.ProviderOrderStatusPending,
+	}).Error; err != nil {
+		t.Fatalf("seed provider order: %v", err)
+	}
+
+	form := okPayNotifyTestForm(shopID, shopToken, providerOrderID, parentTradeID, "0.15000000", "USDT")
+	if err := HandleOkPayNotify(form, "placeholder-okpay-form"); err != nil {
+		t.Fatalf("handle okpay notify: %v", err)
+	}
+
+	reloadedParent, err := data.GetOrderInfoByTradeId(parentTradeID)
+	if err != nil {
+		t.Fatalf("reload parent: %v", err)
+	}
+	if reloadedParent.Status != mdb.StatusPaySuccess {
+		t.Fatalf("parent status = %d, want %d", reloadedParent.Status, mdb.StatusPaySuccess)
+	}
+	if reloadedParent.PayBySubId != 0 {
+		t.Fatalf("parent pay_by_sub_id = %d, want 0", reloadedParent.PayBySubId)
+	}
+	if reloadedParent.Token != "USDT" || reloadedParent.Network != mdb.PaymentProviderOkPay || reloadedParent.ReceiveAddress != "OKPAY" || reloadedParent.ActualAmount != 0.15 {
+		t.Fatalf("okpay parent fields changed: token=%q network=%q address=%q actual=%v", reloadedParent.Token, reloadedParent.Network, reloadedParent.ReceiveAddress, reloadedParent.ActualAmount)
+	}
+	providerRow, err := data.GetProviderOrderByTradeIDAndProvider(parentTradeID, mdb.PaymentProviderOkPay)
+	if err != nil {
+		t.Fatalf("reload provider row: %v", err)
+	}
+	if providerRow.Status != mdb.ProviderOrderStatusPaid {
+		t.Fatalf("provider status = %q, want %q", providerRow.Status, mdb.ProviderOrderStatusPaid)
+	}
+}
+
 func okPayNotifyTestForm(shopID, shopToken, providerOrderID, tradeID, amount, coin string) map[string]string {
 	form := map[string]string{
 		"code":              "200",

src/model/service/order_service.go

@@ -70,15 +70,44 @@ func ensureEnabledOrderAsset(network, token string) (*mdb.ChainToken, error) {
 	return tokenRow, nil
 }
 
+func validateCreateTransactionTokenNetwork(token, network string) error {
+	if (token == "") != (network == "") {
+		return constant.ParamsMarshalErr
+	}
+	return nil
+}
+
+func buildCreateTransactionResponse(order *mdb.Orders) *response.CreateTransactionResponse {
+	return &response.CreateTransactionResponse{
+		TradeId:        order.TradeId,
+		OrderId:        order.OrderId,
+		Amount:         order.Amount,
+		Currency:       order.Currency,
+		ActualAmount:   order.ActualAmount,
+		ReceiveAddress: order.ReceiveAddress,
+		Token:          order.Token,
+		Status:         order.Status,
+		ExpirationTime: carbon.Now().AddMinutes(config.GetOrderExpirationTime()).Timestamp(),
+		PaymentUrl:     fmt.Sprintf("%s/pay/checkout-counter/%s", config.GetAppUri(), order.TradeId),
+	}
+}
+
 // CreateTransaction creates a new payment order.
 func CreateTransaction(req *request.CreateTransactionRequest, apiKey *mdb.ApiKey) (*response.CreateTransactionResponse, error) {
 	token := strings.ToUpper(strings.TrimSpace(req.Token))
 	currency := strings.ToUpper(strings.TrimSpace(req.Currency))
 	network := strings.ToLower(strings.TrimSpace(req.Network))
+	if err := validateCreateTransactionTokenNetwork(token, network); err != nil {
+		return nil, err
+	}
 	notifyURL := strings.TrimSpace(req.NotifyUrl)
 	if err := security.ValidatePublicHTTPURL(notifyURL); err != nil {
 		return nil, constant.NotifyURLErr
 	}
+	paymentType := mdb.PaymentTypeGmpay
+	if strings.EqualFold(req.PaymentType, mdb.PaymentTypeEpay) {
+		paymentType = mdb.PaymentTypeEpay
+	}
 
 	gCreateTransactionLock.Lock()
 	defer gCreateTransactionLock.Unlock()
@@ -93,6 +122,32 @@ func CreateTransaction(req *request.CreateTransactionRequest, apiKey *mdb.ApiKey
 		return nil, constant.OrderAlreadyExists
 	}
 
+	decimalPayAmount := decimal.NewFromFloat(payAmount)
+	if decimalPayAmount.Cmp(decimal.NewFromFloat(CnyMinimumPaymentAmount)) == -1 {
+		return nil, constant.PayAmountErr
+	}
+
+	if token == "" && network == "" {
+		tradeID := GenerateCode()
+		order := &mdb.Orders{
+			TradeId:     tradeID,
+			OrderId:     req.OrderId,
+			Amount:      payAmount,
+			Currency:    currency,
+			Status:      mdb.StatusWaitSelect,
+			NotifyUrl:   notifyURL,
+			RedirectUrl: req.RedirectUrl,
+			Name:        req.Name,
+			PaymentType: paymentType,
+			PayProvider: mdb.PaymentProviderOnChain,
+			ApiKeyID:    apiKeyID(apiKey),
+		}
+		if err = data.CreateOrderWithTransaction(dao.Mdb, order); err != nil {
+			return nil, err
+		}
+		return buildCreateTransactionResponse(order), nil
+	}
+
 	if !data.IsChainEnabled(network) {
 		return nil, constant.ChainNotEnabled
 	}
@@ -105,11 +160,7 @@ func CreateTransaction(req *request.CreateTransactionRequest, apiKey *mdb.ApiKey
 		return nil, constant.RateAmountErr
 	}
 
-	decimalPayAmount := decimal.NewFromFloat(payAmount)
 	decimalTokenAmount := decimalPayAmount.Mul(decimal.NewFromFloat(rate))
-	if decimalPayAmount.Cmp(decimal.NewFromFloat(CnyMinimumPaymentAmount)) == -1 {
-		return nil, constant.PayAmountErr
-	}
 	if decimalTokenAmount.Cmp(decimal.NewFromFloat(UsdtMinimumPaymentAmount)) == -1 {
 		return nil, constant.PayAmountErr
 	}
@@ -146,7 +197,7 @@ func CreateTransaction(req *request.CreateTransactionRequest, apiKey *mdb.ApiKey
 		NotifyUrl:      notifyURL,
 		RedirectUrl:    req.RedirectUrl,
 		Name:           req.Name,
-		PaymentType:    req.PaymentType,
+		PaymentType:    paymentType,
 		PayProvider:    mdb.PaymentProviderOnChain,
 		ApiKeyID:       apiKeyID(apiKey),
 	}
@@ -161,19 +212,7 @@ func CreateTransaction(req *request.CreateTransactionRequest, apiKey *mdb.ApiKey
 		return nil, err
 	}
 
-	expirationTime := carbon.Now().AddMinutes(config.GetOrderExpirationTime()).Timestamp()
-	resp := &response.CreateTransactionResponse{
-		TradeId:        order.TradeId,
-		OrderId:        order.OrderId,
-		Amount:         order.Amount,
-		Currency:       order.Currency,
-		ActualAmount:   order.ActualAmount,
-		ReceiveAddress: order.ReceiveAddress,
-		Token:          order.Token,
-		ExpirationTime: expirationTime,
-		PaymentUrl:     fmt.Sprintf("%s/pay/checkout-counter/%s", config.GetAppUri(), order.TradeId),
-	}
-	return resp, nil
+	return buildCreateTransactionResponse(order), nil
 }
 
 // OrderProcessing marks an order as paid and releases its sqlite reservation.
@@ -206,15 +245,21 @@ func OrderProcessing(req *request.OrderProcessingRequest) error {
 		return err
 	}
 
-	if err = data.UnLockTransaction(req.Network, req.ReceiveAddress, req.Token, req.Amount); err != nil {
-		log.Sugar.Warnf("[order] unlock transaction after pay success failed, trade_id=%s, err=%v", req.TradeId, err)
-	}
-
 	// Load order to check parent-child relationship
 	order, err := data.GetOrderInfoByTradeId(req.TradeId)
 	if err != nil {
+		if strings.TrimSpace(req.Network) != "" && strings.TrimSpace(req.ReceiveAddress) != "" && strings.TrimSpace(req.Token) != "" && req.Amount > 0 {
+			if unlockErr := data.UnLockTransaction(req.Network, req.ReceiveAddress, req.Token, req.Amount); unlockErr != nil {
+				log.Sugar.Warnf("[order] fallback unlock transaction after pay success failed, trade_id=%s, err=%v", req.TradeId, unlockErr)
+			}
+		}
 		return fmt.Errorf("load paid order failed, trade_id=%s: %w", req.TradeId, err)
 	}
+	if hasTransactionLock(order) {
+		if err = data.UnLockTransaction(order.Network, order.ReceiveAddress, order.Token, order.ActualAmount); err != nil {
+			log.Sugar.Warnf("[order] unlock transaction after pay success failed, trade_id=%s, err=%v", order.TradeId, err)
+		}
+	}
 
 	// Parent order paid directly: expire all sub-orders and release their locks
 	if order.ParentTradeId == "" {
@@ -232,8 +277,10 @@ func OrderProcessing(req *request.OrderProcessingRequest) error {
 					log.Sugar.Warnf("[order] expire provider order failed, trade_id=%s, provider=%s, err=%v", sub.TradeId, sub.PayProvider, err)
 				}
 			}
-			if err = data.UnLockTransaction(sub.Network, sub.ReceiveAddress, sub.Token, sub.ActualAmount); err != nil {
-				log.Sugar.Warnf("[order] unlock sub-order transaction failed, trade_id=%s, err=%v", sub.TradeId, err)
+			if hasTransactionLock(&sub) {
+				if err = data.UnLockTransaction(sub.Network, sub.ReceiveAddress, sub.Token, sub.ActualAmount); err != nil {
+					log.Sugar.Warnf("[order] unlock sub-order transaction failed, trade_id=%s, err=%v", sub.TradeId, err)
+				}
 			}
 		}
 		return nil
@@ -284,8 +331,10 @@ func OrderProcessing(req *request.OrderProcessingRequest) error {
 	}
 
 	// Release parent's own wallet lock
-	if err = data.UnLockTransaction(parent.Network, parent.ReceiveAddress, parent.Token, parent.ActualAmount); err != nil {
-		log.Sugar.Warnf("[order] unlock parent transaction failed, parent_trade_id=%s, err=%v", parent.TradeId, err)
+	if hasTransactionLock(parent) {
+		if err = data.UnLockTransaction(parent.Network, parent.ReceiveAddress, parent.Token, parent.ActualAmount); err != nil {
+			log.Sugar.Warnf("[order] unlock parent transaction failed, parent_trade_id=%s, err=%v", parent.TradeId, err)
+		}
 	}
 
 	// Release sibling locks after their status transitions commit.
@@ -295,8 +344,10 @@ func OrderProcessing(req *request.OrderProcessingRequest) error {
 				log.Sugar.Warnf("[order] expire sibling provider order failed, trade_id=%s, provider=%s, err=%v", sib.TradeId, sib.PayProvider, err)
 			}
 		}
-		if err = data.UnLockTransaction(sib.Network, sib.ReceiveAddress, sib.Token, sib.ActualAmount); err != nil {
-			log.Sugar.Warnf("[order] unlock sibling transaction failed, trade_id=%s, err=%v", sib.TradeId, err)
+		if hasTransactionLock(&sib) {
+			if err = data.UnLockTransaction(sib.Network, sib.ReceiveAddress, sib.Token, sib.ActualAmount); err != nil {
+				log.Sugar.Warnf("[order] unlock sibling transaction failed, trade_id=%s, err=%v", sib.TradeId, err)
+			}
 		}
 	}
 
@@ -448,9 +499,20 @@ func isOnChainOrder(payProvider string) bool {
 	return payProvider == "" || payProvider == mdb.PaymentProviderOnChain
 }
 
-const MaxSubOrders = 2
+func hasTransactionLock(order *mdb.Orders) bool {
+	return order != nil &&
+		isOnChainOrder(order.PayProvider) &&
+		strings.TrimSpace(order.Network) != "" &&
+		strings.TrimSpace(order.ReceiveAddress) != "" &&
+		strings.TrimSpace(order.Token) != "" &&
+		order.ActualAmount > 0
+}
 
-// SwitchNetwork creates or returns an existing sub-order for a different token+network.
+const MaxSubOrders = 1
+
+// SwitchNetwork completes a status=4 placeholder in place, or creates/returns
+// an existing sub-order for a different payment target once the parent is
+// already concrete.
 func SwitchNetwork(req *request.SwitchNetworkRequest) (*response.CheckoutCounterResponse, error) {
 	gCreateTransactionLock.Lock()
 	defer gCreateTransactionLock.Unlock()
@@ -469,7 +531,7 @@ func SwitchNetwork(req *request.SwitchNetworkRequest) (*response.CheckoutCounter
 	if parent.ParentTradeId != "" {
 		return nil, constant.CannotSwitchSubOrder
 	}
-	if parent.Status != mdb.StatusWaitPay {
+	if parent.Status != mdb.StatusWaitPay && parent.Status != mdb.StatusWaitSelect {
 		return nil, constant.OrderNotWaitPay
 	}
 
@@ -477,6 +539,10 @@ func SwitchNetwork(req *request.SwitchNetworkRequest) (*response.CheckoutCounter
 		return switchToOkPay(parent, token)
 	}
 
+	if parent.Status == mdb.StatusWaitSelect {
+		return completeWaitSelectOrder(parent, token, network)
+	}
+
 	// 2. Same token+network as parent → mark selected and return
 	if strings.EqualFold(parent.Token, token) && strings.EqualFold(parent.Network, network) {
 		_ = data.MarkOrderSelected(parent.TradeId)
@@ -497,8 +563,9 @@ func SwitchNetwork(req *request.SwitchNetworkRequest) (*response.CheckoutCounter
 		return buildCheckoutResponse(existing), nil
 	}
 
-	// 4. Check sub-order limit
-	count, err := data.CountActiveSubOrders(parent.TradeId)
+	// 4. Only one sub-order may ever be created under a parent. Existing
+	// active sub-orders are reused above; any other target after that is blocked.
+	count, err := data.CountSubOrders(parent.TradeId)
 	if err != nil {
 		return nil, err
 	}
@@ -585,7 +652,63 @@ func SwitchNetwork(req *request.SwitchNetworkRequest) (*response.CheckoutCounter
 	return buildCheckoutResponse(subOrder), nil
 }
 
+func completeWaitSelectOrder(parent *mdb.Orders, token string, network string) (*response.CheckoutCounterResponse, error) {
+	if !data.IsChainEnabled(network) {
+		return nil, constant.ChainNotEnabled
+	}
+	if _, err := ensureEnabledOrderAsset(network, token); err != nil {
+		return nil, err
+	}
+
+	rate := config.GetRateForCoin(strings.ToLower(token), strings.ToLower(parent.Currency))
+	if rate <= 0 {
+		return nil, constant.RateAmountErr
+	}
+	decimalPayAmount := decimal.NewFromFloat(parent.Amount)
+	decimalTokenAmount := decimalPayAmount.Mul(decimal.NewFromFloat(rate))
+	if decimalTokenAmount.Cmp(decimal.NewFromFloat(UsdtMinimumPaymentAmount)) == -1 {
+		return nil, constant.PayAmountErr
+	}
+
+	walletAddress, err := data.GetAvailableWalletAddressByNetwork(network)
+	if err != nil {
+		return nil, err
+	}
+	if len(walletAddress) <= 0 {
+		return nil, constant.NotAvailableWalletAddress
+	}
+
+	amount := math.MustParsePrecFloat64(decimalTokenAmount.InexactFloat64(), data.GetAmountPrecision())
+	availableAddress, availableAmount, err := ReserveAvailableWalletAndAmount(parent.TradeId, network, token, amount, walletAddress)
+	if err != nil {
+		return nil, err
+	}
+	if availableAddress == "" {
+		return nil, constant.NotAvailableAmountErr
+	}
+
+	updated, err := data.CompleteWaitSelectOrder(parent.TradeId, network, token, availableAddress, availableAmount)
+	if err != nil {
+		_ = data.UnLockTransactionByTradeId(parent.TradeId)
+		return nil, err
+	}
+	if !updated {
+		_ = data.UnLockTransactionByTradeId(parent.TradeId)
+		return nil, constant.OrderStatusConflict
+	}
+
+	order, err := data.GetOrderInfoByTradeId(parent.TradeId)
+	if err != nil {
+		return nil, err
+	}
+	return buildCheckoutResponse(order), nil
+}
+
 func buildCheckoutResponse(order *mdb.Orders) *response.CheckoutCounterResponse {
+	paymentType := mdb.PaymentTypeGmpay
+	if strings.EqualFold(order.PaymentType, mdb.PaymentTypeEpay) {
+		paymentType = mdb.PaymentTypeEpay
+	}
 	return &response.CheckoutCounterResponse{
 		TradeId:        order.TradeId,
 		Amount:         order.Amount,
@@ -594,14 +717,93 @@ func buildCheckoutResponse(order *mdb.Orders) *response.CheckoutCounterResponse
 		Currency:       order.Currency,
 		ReceiveAddress: order.ReceiveAddress,
 		Network:        order.Network,
+		Status:         order.Status,
+		PaymentType:    strings.ToLower(paymentType),
 		ExpirationTime: order.CreatedAt.AddMinutes(config.GetOrderExpirationTime()).TimestampMilli(),
 		RedirectUrl:    order.RedirectUrl,
-		PaymentUrl:     fmt.Sprintf("%s/pay/checkout-counter/%s", config.GetAppUri(), order.TradeId),
 		CreatedAt:      order.CreatedAt.TimestampMilli(),
 		IsSelected:     order.IsSelected,
 	}
 }
 
+func completeWaitSelectOkPayOrder(parent *mdb.Orders, token string) (*response.CheckoutCounterResponse, error) {
+	rate := config.GetRateForCoin(strings.ToLower(token), strings.ToLower(parent.Currency))
+	if rate <= 0 {
+		return nil, constant.RateAmountErr
+	}
+	decimalPayAmount := decimal.NewFromFloat(parent.Amount)
+	decimalTokenAmount := decimalPayAmount.Mul(decimal.NewFromFloat(rate))
+	if decimalTokenAmount.Cmp(decimal.NewFromFloat(UsdtMinimumPaymentAmount)) == -1 {
+		return nil, constant.PayAmountErr
+	}
+
+	amount := math.MustParsePrecFloat64(decimalTokenAmount.InexactFloat64(), data.GetAmountPrecision())
+	returnURL := strings.TrimSpace(parent.RedirectUrl)
+	if returnURL == "" {
+		returnURL = data.GetOkPayReturnURL()
+	}
+	if returnURL == "" {
+		returnURL = fmt.Sprintf("%s/pay/checkout-counter/%s", config.GetAppUri(), parent.TradeId)
+	}
+
+	tx := dao.Mdb.Begin()
+	providerRow := &mdb.ProviderOrder{
+		TradeId:         parent.TradeId,
+		Provider:        mdb.PaymentProviderOkPay,
+		ProviderOrderID: "",
+		PayURL:          "",
+		Amount:          amount,
+		Coin:            token,
+		Status:          mdb.ProviderOrderStatusCreating,
+		NotifyRaw:       "",
+	}
+	if err := data.UpsertProviderOrderCreatingWithTransaction(tx, providerRow); err != nil {
+		tx.Rollback()
+		return nil, err
+	}
+	if err := tx.Commit().Error; err != nil {
+		tx.Rollback()
+		return nil, err
+	}
+
+	okpayOrder, err := createOkPayDepositOrder(parent.TradeId, amount, token, returnURL)
+	if err != nil {
+		_ = data.MarkProviderOrderFailed(parent.TradeId, mdb.PaymentProviderOkPay)
+		return nil, constant.PaymentProviderCreateErr
+	}
+
+	finalizeTx := dao.Mdb.Begin()
+	if err = data.UpdateProviderOrderCreatedWithTransaction(finalizeTx, parent.TradeId, mdb.PaymentProviderOkPay, okpayOrder.ProviderOrderID, okpayOrder.PayURL); err != nil {
+		finalizeTx.Rollback()
+		_ = data.MarkProviderOrderFailed(parent.TradeId, mdb.PaymentProviderOkPay)
+		return nil, err
+	}
+	updated, err := data.CompleteWaitSelectOkPayOrderWithTransaction(finalizeTx, parent.TradeId, token, amount)
+	if err != nil {
+		finalizeTx.Rollback()
+		_ = data.MarkProviderOrderFailed(parent.TradeId, mdb.PaymentProviderOkPay)
+		return nil, err
+	}
+	if !updated {
+		finalizeTx.Rollback()
+		_ = data.MarkProviderOrderFailed(parent.TradeId, mdb.PaymentProviderOkPay)
+		return nil, constant.OrderStatusConflict
+	}
+	if err = finalizeTx.Commit().Error; err != nil {
+		finalizeTx.Rollback()
+		_ = data.MarkProviderOrderFailed(parent.TradeId, mdb.PaymentProviderOkPay)
+		return nil, err
+	}
+
+	order, err := data.GetOrderInfoByTradeId(parent.TradeId)
+	if err != nil {
+		return nil, err
+	}
+	resp := buildCheckoutResponse(order)
+	resp.PaymentUrl = okpayOrder.PayURL
+	return resp, nil
+}
+
 func switchToOkPay(parent *mdb.Orders, token string) (*response.CheckoutCounterResponse, error) {
 	if !data.GetOkPayEnabled() {
 		return nil, constant.PaymentProviderNotEnabled
@@ -613,6 +815,29 @@ func switchToOkPay(parent *mdb.Orders, token string) (*response.CheckoutCounterR
 		return nil, constant.PaymentProviderNotSupport
 	}
 
+	if parent.Status == mdb.StatusWaitSelect {
+		return completeWaitSelectOkPayOrder(parent, token)
+	}
+
+	if parent.PayProvider == mdb.PaymentProviderOkPay && strings.EqualFold(parent.Token, token) {
+		providerRow, err := data.GetProviderOrderByTradeIDAndProvider(parent.TradeId, mdb.PaymentProviderOkPay)
+		if err != nil {
+			return nil, err
+		}
+		if providerRow.ID == 0 || strings.TrimSpace(providerRow.PayURL) == "" {
+			return nil, constant.SystemErr
+		}
+		_ = data.MarkOrderSelected(parent.TradeId)
+		_ = data.RefreshOrderExpiration(parent.TradeId)
+		order, err := data.GetOrderInfoByTradeId(parent.TradeId)
+		if err != nil {
+			return nil, err
+		}
+		resp := buildCheckoutResponse(order)
+		resp.PaymentUrl = providerRow.PayURL
+		return resp, nil
+	}
+
 	existing, err := data.GetSubOrderByTokenPayProvider(parent.TradeId, token, mdb.PaymentProviderOkPay)
 	if err != nil {
 		return nil, err
@@ -625,16 +850,21 @@ func switchToOkPay(parent *mdb.Orders, token string) (*response.CheckoutCounterR
 		if providerRow.ID == 0 || strings.TrimSpace(providerRow.PayURL) == "" {
 			return nil, constant.SystemErr
 		}
-		_ = data.MarkOrderSelected(parent.TradeId)
+		updated, markErr := data.MarkProviderSwitchParentSelectedWithTransaction(dao.Mdb, parent.TradeId)
+		if markErr != nil {
+			return nil, markErr
+		}
+		if !updated {
+			return nil, constant.OrderStatusConflict
+		}
 		_ = data.MarkOrderSelected(existing.TradeId)
-		_ = data.RefreshOrderExpiration(parent.TradeId)
 		existing.IsSelected = true
 		resp := buildCheckoutResponse(existing)
 		resp.PaymentUrl = providerRow.PayURL
 		return resp, nil
 	}
 
-	count, err := data.CountActiveSubOrders(parent.TradeId)
+	count, err := data.CountSubOrders(parent.TradeId)
 	if err != nil {
 		return nil, err
 	}
@@ -711,14 +941,33 @@ func switchToOkPay(parent *mdb.Orders, token string) (*response.CheckoutCounterR
 		_ = data.ExpireOrderByTradeID(subTradeID)
 		return nil, constant.PaymentProviderCreateErr
 	}
-	if err = data.UpdateProviderOrderCreated(subTradeID, mdb.PaymentProviderOkPay, okpayOrder.ProviderOrderID, okpayOrder.PayURL); err != nil {
+
+	finalizeTx := dao.Mdb.Begin()
+	if err = data.UpdateProviderOrderCreatedWithTransaction(finalizeTx, subTradeID, mdb.PaymentProviderOkPay, okpayOrder.ProviderOrderID, okpayOrder.PayURL); err != nil {
+		finalizeTx.Rollback()
+		_ = data.MarkProviderOrderFailed(subTradeID, mdb.PaymentProviderOkPay)
+		_ = data.ExpireOrderByTradeID(subTradeID)
+		return nil, err
+	}
+	updated, err := data.MarkProviderSwitchParentSelectedWithTransaction(finalizeTx, parent.TradeId)
+	if err != nil {
+		finalizeTx.Rollback()
+		_ = data.MarkProviderOrderFailed(subTradeID, mdb.PaymentProviderOkPay)
+		_ = data.ExpireOrderByTradeID(subTradeID)
+		return nil, err
+	}
+	if !updated {
+		finalizeTx.Rollback()
+		_ = data.MarkProviderOrderFailed(subTradeID, mdb.PaymentProviderOkPay)
+		_ = data.ExpireOrderByTradeID(subTradeID)
+		return nil, constant.OrderStatusConflict
+	}
+	if err = finalizeTx.Commit().Error; err != nil {
+		finalizeTx.Rollback()
 		_ = data.MarkProviderOrderFailed(subTradeID, mdb.PaymentProviderOkPay)
 		_ = data.ExpireOrderByTradeID(subTradeID)
 		return nil, err
 	}
-
-	_ = data.MarkOrderSelected(parent.TradeId)
-	_ = data.RefreshOrderExpiration(parent.TradeId)
 
 	resp := buildCheckoutResponse(subOrder)
 	resp.PaymentUrl = okpayOrder.PayURL

src/model/service/order_service_test.go

@@ -87,6 +87,85 @@ func TestCreateTransactionRejectsPrivateNotifyURL(t *testing.T) {
 	}
 }
 
+func TestCreateTransactionCreatesWaitSelectPlaceholderWithoutTokenNetwork(t *testing.T) {
+	cleanup := testutil.SetupTestDatabases(t)
+	defer cleanup()
+
+	req := newCreateTransactionRequest("order_wait_select_1", 12.34)
+	req.Token = ""
+	req.Network = ""
+	resp, err := CreateTransaction(req, nil)
+	if err != nil {
+		t.Fatalf("create placeholder transaction: %v", err)
+	}
+	if resp.Status != mdb.StatusWaitSelect {
+		t.Fatalf("response status = %d, want %d", resp.Status, mdb.StatusWaitSelect)
+	}
+	if resp.Token != "" || resp.ReceiveAddress != "" || resp.ActualAmount != 0 {
+		t.Fatalf("placeholder chain fields = token %q address %q actual %.4f", resp.Token, resp.ReceiveAddress, resp.ActualAmount)
+	}
+
+	order, err := data.GetOrderInfoByTradeId(resp.TradeId)
+	if err != nil {
+		t.Fatalf("reload placeholder order: %v", err)
+	}
+	if order.Status != mdb.StatusWaitSelect {
+		t.Fatalf("order status = %d, want %d", order.Status, mdb.StatusWaitSelect)
+	}
+	if order.PaymentType != mdb.PaymentTypeGmpay {
+		t.Fatalf("placeholder payment_type = %q, want %q", order.PaymentType, mdb.PaymentTypeGmpay)
+	}
+	if order.Token != "" || order.Network != "" || order.ReceiveAddress != "" || order.ActualAmount != 0 {
+		t.Fatalf("placeholder order has chain fields: %+v", order)
+	}
+
+	var locks int64
+	if err := dao.RuntimeDB.Model(&mdb.TransactionLock{}).Where("trade_id = ?", resp.TradeId).Count(&locks).Error; err != nil {
+		t.Fatalf("count transaction locks: %v", err)
+	}
+	if locks != 0 {
+		t.Fatalf("placeholder lock count = %d, want 0", locks)
+	}
+}
+
+func TestCreateTransactionRejectsPartialTokenNetwork(t *testing.T) {
+	cleanup := testutil.SetupTestDatabases(t)
+	defer cleanup()
+
+	req := newCreateTransactionRequest("order_partial_token_network_1", 1)
+	req.Token = ""
+	if _, err := CreateTransaction(req, nil); err != constant.ParamsMarshalErr {
+		t.Fatalf("missing token error = %v, want %v", err, constant.ParamsMarshalErr)
+	}
+
+	req = newCreateTransactionRequest("order_partial_token_network_2", 1)
+	req.Network = ""
+	if _, err := CreateTransaction(req, nil); err != constant.ParamsMarshalErr {
+		t.Fatalf("missing network error = %v, want %v", err, constant.ParamsMarshalErr)
+	}
+}
+
+func TestCreateTransactionNormalizesEpayPaymentTypeCase(t *testing.T) {
+	cleanup := testutil.SetupTestDatabases(t)
+	defer cleanup()
+
+	req := newCreateTransactionRequest("order_epay_payment_type_1", 1)
+	req.Token = ""
+	req.Network = ""
+	req.PaymentType = "epay"
+	resp, err := CreateTransaction(req, nil)
+	if err != nil {
+		t.Fatalf("create epay-compatible transaction: %v", err)
+	}
+	order, err := data.GetOrderInfoByTradeId(resp.TradeId)
+	if err != nil {
+		t.Fatalf("reload order: %v", err)
+	}
+	if order.PaymentType != mdb.PaymentTypeEpay {
+		t.Fatalf("payment_type = %q, want %q", order.PaymentType, mdb.PaymentTypeEpay)
+	}
+}
+
 func TestCreateTransactionAssignsIncrementedAmountsAndLocks(t *testing.T) {
 	cleanup := testutil.SetupTestDatabases(t)
 	defer cleanup()
@@ -459,6 +538,146 @@ func TestSwitchNetworkCreatesTonSubOrderAndRawLock(t *testing.T) {
 	}
 }
 
+func TestSwitchNetworkCompletesWaitSelectPlaceholderInPlace(t *testing.T) {
+	cleanup := testutil.SetupTestDatabases(t)
+	defer cleanup()
+
+	if err := data.SetSetting("rate", "rate.forced_rate_list", `{"cny":{"usdt":0.1}}`, "json"); err != nil {
+		t.Fatalf("set forced rate: %v", err)
+	}
+	if _, err := data.AddWalletAddress("TWaitSelectAddress001"); err != nil {
+		t.Fatalf("add tron wallet: %v", err)
+	}
+
+	req := newCreateTransactionRequest("order_wait_select_switch_1", 10)
+	req.Token = ""
+	req.Network = ""
+	parentResp, err := CreateTransaction(req, nil)
+	if err != nil {
+		t.Fatalf("create placeholder: %v", err)
+	}
+	if parentResp.Status != mdb.StatusWaitSelect {
+		t.Fatalf("parent response status = %d, want %d", parentResp.Status, mdb.StatusWaitSelect)
+	}
+
+	switched, err := SwitchNetwork(&request.SwitchNetworkRequest{
+		TradeId: parentResp.TradeId,
+		Token:   "USDT",
+		Network: mdb.NetworkTron,
+	})
+	if err != nil {
+		t.Fatalf("switch placeholder to tron/usdt: %v", err)
+	}
+	if switched.TradeId != parentResp.TradeId {
+		t.Fatalf("switch returned trade_id = %q, want parent %q", switched.TradeId, parentResp.TradeId)
+	}
+	if switched.Status != mdb.StatusWaitPay {
+		t.Fatalf("switch status = %d, want %d", switched.Status, mdb.StatusWaitPay)
+	}
+	if switched.IsSelected {
+		t.Fatal("switch is_selected = true, want false")
+	}
+	if switched.PaymentUrl != "" {
+		t.Fatalf("switch payment_url = %q, want empty for unselected chain parent", switched.PaymentUrl)
+	}
+	if switched.Token != "USDT" || switched.Network != mdb.NetworkTron || switched.ReceiveAddress != "TWaitSelectAddress001" {
+		t.Fatalf("switch chain fields = token %q network %q address %q", switched.Token, switched.Network, switched.ReceiveAddress)
+	}
+	if got := fmt.Sprintf("%.2f", switched.ActualAmount); got != "1.00" {
+		t.Fatalf("switch actual amount = %s, want 1.00", got)
+	}
+
+	parent, err := data.GetOrderInfoByTradeId(parentResp.TradeId)
+	if err != nil {
+		t.Fatalf("reload parent: %v", err)
+	}
+	if parent.Status != mdb.StatusWaitPay || parent.ParentTradeId != "" {
+		t.Fatalf("parent status/parent_trade_id = %d/%q", parent.Status, parent.ParentTradeId)
+	}
+	if parent.IsSelected {
+		t.Fatal("parent is_selected = true, want false")
+	}
+	if parent.PaymentType != mdb.PaymentTypeGmpay {
+		t.Fatalf("parent payment_type = %q, want %q", parent.PaymentType, mdb.PaymentTypeGmpay)
+	}
+	count, err := data.CountActiveSubOrders(parent.TradeId)
+	if err != nil {
+		t.Fatalf("count sub orders: %v", err)
+	}
+	if count != 0 {
+		t.Fatalf("active sub-order count = %d, want 0", count)
+	}
+	lockTradeID, err := data.GetTradeIdByWalletAddressAndAmountAndToken(mdb.NetworkTron, parent.ReceiveAddress, parent.Token, parent.ActualAmount)
+	if err != nil {
+		t.Fatalf("lookup parent lock: %v", err)
+	}
+	if lockTradeID != parent.TradeId {
+		t.Fatalf("parent lock trade_id = %q, want %q", lockTradeID, parent.TradeId)
+	}
+}
+
+func TestSwitchNetworkAfterWaitSelectCompletionUsesExistingSubOrderFlow(t *testing.T) {
+	cleanup := testutil.SetupTestDatabases(t)
+	defer cleanup()
+
+	if err := data.SetSetting("rate", "rate.forced_rate_list", `{"cny":{"usdt":0.1}}`, "json"); err != nil {
+		t.Fatalf("set forced rate: %v", err)
+	}
+	if _, err := data.AddWalletAddress("TWaitSelectAddress002"); err != nil {
+		t.Fatalf("add tron wallet: %v", err)
+	}
+	if _, err := data.AddWalletAddressWithNetwork(mdb.NetworkEthereum, "0xA1B2c3D4e5F60718293aBcDeF001122334455668"); err != nil {
+		t.Fatalf("add ethereum wallet: %v", err)
+	}
+
+	req := newCreateTransactionRequest("order_wait_select_reswitch_1", 10)
+	req.Token = ""
+	req.Network = ""
+	parentResp, err := CreateTransaction(req, nil)
+	if err != nil {
+		t.Fatalf("create placeholder: %v", err)
+	}
+	first, err := SwitchNetwork(&request.SwitchNetworkRequest{
+		TradeId: parentResp.TradeId,
+		Token:   "USDT",
+		Network: mdb.NetworkTron,
+	})
+	if err != nil {
+		t.Fatalf("first switch: %v", err)
+	}
+
+	second, err := SwitchNetwork(&request.SwitchNetworkRequest{
+		TradeId: parentResp.TradeId,
+		Token:   "USDT",
+		Network: mdb.NetworkEthereum,
+	})
+	if err != nil {
+		t.Fatalf("second switch: %v", err)
+	}
+	if second.TradeId == first.TradeId {
+		t.Fatalf("second switch trade_id = parent %q, want sub-order", second.TradeId)
+	}
+	if second.Network != mdb.NetworkEthereum || second.Token != "USDT" {
+		t.Fatalf("second switch token/network = %s/%s", second.Token, second.Network)
+	}
+	count, err := data.CountActiveSubOrders(parentResp.TradeId)
+	if err != nil {
+		t.Fatalf("count active sub orders: %v", err)
+	}
+	if count != 1 {
+		t.Fatalf("active sub-order count = %d, want 1", count)
+	}
+
+	_, err = SwitchNetwork(&request.SwitchNetworkRequest{
+		TradeId: parentResp.TradeId,
+		Token:   "USDT",
+		Network: mdb.NetworkBsc,
+	})
+	if err != constant.SubOrderLimitExceeded {
+		t.Fatalf("third switch error = %v, want %v", err, constant.SubOrderLimitExceeded)
+	}
+}
+
 func TestSwitchNetworkRejectsUnsupportedTonToken(t *testing.T) {
 	cleanup := testutil.SetupTestDatabases(t)
 	defer cleanup()
@@ -1219,7 +1438,6 @@ func TestOrderProcessingSubOrderExpiresSiblingsAndReleasesLocks(t *testing.T) {
 		t.Fatalf("create parent order: %v", err)
 	}
 
-	// Create two sub-orders on different networks.
 	subEthResp, err := SwitchNetwork(&request.SwitchNetworkRequest{
 		TradeId: parentResp.TradeId,
 		Token:   "usdt",
@@ -1229,13 +1447,29 @@ func TestOrderProcessingSubOrderExpiresSiblingsAndReleasesLocks(t *testing.T) {
 		t.Fatalf("switch to ethereum sub-order: %v", err)
 	}
 
-	subBscResp, err := SwitchNetwork(&request.SwitchNetworkRequest{
-		TradeId: parentResp.TradeId,
-		Token:   "usdt",
-		Network: mdb.NetworkBsc,
-	})
-	if err != nil {
-		t.Fatalf("switch to bsc sub-order: %v", err)
+	bscTradeID := GenerateCode()
+	bscAddress := strings.ToLower("0xBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB")
+	subBsc := &mdb.Orders{
+		TradeId:         bscTradeID,
+		OrderId:         bscTradeID,
+		ParentTradeId:   parentResp.TradeId,
+		Amount:          parentResp.Amount,
+		Currency:        parentResp.Currency,
+		ActualAmount:    subEthResp.ActualAmount,
+		ReceiveAddress:  bscAddress,
+		Token:           "USDT",
+		Network:         mdb.NetworkBsc,
+		Status:          mdb.StatusWaitPay,
+		IsSelected:      true,
+		CallBackConfirm: mdb.CallBackConfirmOk,
+		PaymentType:     mdb.PaymentTypeGmpay,
+		PayProvider:     mdb.PaymentProviderOnChain,
+	}
+	if err := dao.Mdb.Create(subBsc).Error; err != nil {
+		t.Fatalf("seed bsc sibling sub-order: %v", err)
+	}
+	if err := data.LockTransaction(mdb.NetworkBsc, bscAddress, "USDT", bscTradeID, subBsc.ActualAmount, time.Hour); err != nil {
+		t.Fatalf("lock bsc sibling amount: %v", err)
 	}
 
 	// Pay the Ethereum sub-order.
@@ -1252,12 +1486,12 @@ func TestOrderProcessingSubOrderExpiresSiblingsAndReleasesLocks(t *testing.T) {
 	}
 
 	// BSC sibling must be expired.
-	subBsc, err := data.GetOrderInfoByTradeId(subBscResp.TradeId)
+	reloadedBsc, err := data.GetOrderInfoByTradeId(subBsc.TradeId)
 	if err != nil {
 		t.Fatalf("reload bsc sub-order: %v", err)
 	}
-	if subBsc.Status != mdb.StatusExpired {
-		t.Fatalf("bsc sibling status = %d, want %d (expired)", subBsc.Status, mdb.StatusExpired)
+	if reloadedBsc.Status != mdb.StatusExpired {
+		t.Fatalf("bsc sibling status = %d, want %d (expired)", reloadedBsc.Status, mdb.StatusExpired)
 	}
 
 	// Parent runtime lock must be released.
@@ -1272,7 +1506,7 @@ func TestOrderProcessingSubOrderExpiresSiblingsAndReleasesLocks(t *testing.T) {
 
 	// BSC sibling runtime lock must be released.
 	sibLock, err := data.GetTradeIdByWalletAddressAndAmountAndToken(
-		mdb.NetworkBsc, subBscResp.ReceiveAddress, subBscResp.Token, subBscResp.ActualAmount)
+		mdb.NetworkBsc, subBsc.ReceiveAddress, subBsc.Token, subBsc.ActualAmount)
 	if err != nil {
 		t.Fatalf("check bsc sibling runtime lock: %v", err)
 	}

src/model/service/pay_service.go

@@ -1,8 +1,11 @@
 package service
 
 import (
+	"strings"
+
 	"github.com/GMWalletApp/epusdt/config"
 	"github.com/GMWalletApp/epusdt/model/data"
+	"github.com/GMWalletApp/epusdt/model/mdb"
 	"github.com/GMWalletApp/epusdt/model/response"
 	"github.com/GMWalletApp/epusdt/util/constant"
 )
@@ -20,6 +23,10 @@ func GetCheckoutCounterByTradeId(tradeId string) (*response.CheckoutCounterRespo
 	if orderInfo.ID <= 0 {
 		return nil, ErrOrder
 	}
+	paymentType := mdb.PaymentTypeGmpay
+	if strings.EqualFold(orderInfo.PaymentType, mdb.PaymentTypeEpay) {
+		paymentType = mdb.PaymentTypeEpay
+	}
 
 	resp := &response.CheckoutCounterResponse{
 		TradeId:        orderInfo.TradeId,
@@ -29,10 +36,21 @@ func GetCheckoutCounterByTradeId(tradeId string) (*response.CheckoutCounterRespo
 		Currency:       orderInfo.Currency,
 		ReceiveAddress: orderInfo.ReceiveAddress,
 		Network:        orderInfo.Network,
+		Status:         orderInfo.Status,
+		PaymentType:    strings.ToLower(paymentType),
 		ExpirationTime: orderInfo.CreatedAt.AddMinutes(config.GetOrderExpirationTime()).TimestampMilli(),
 		RedirectUrl:    orderInfo.RedirectUrl,
 		CreatedAt:      orderInfo.CreatedAt.TimestampMilli(),
 		IsSelected:     orderInfo.IsSelected,
 	}
+	if orderInfo.PayProvider == mdb.PaymentProviderOkPay {
+		providerRow, rowErr := data.GetProviderOrderByTradeIDAndProvider(orderInfo.TradeId, mdb.PaymentProviderOkPay)
+		if rowErr != nil {
+			return nil, rowErr
+		}
+		if providerRow.ID > 0 {
+			resp.PaymentUrl = providerRow.PayURL
+		}
+	}
 	return resp, nil
 }