feat(billing): 火山方舟视频计费 - 支持真实 Token 预授权与结算

Refs #228

Co-authored-by: MasterChiefCN <49179444+MasterChiefCN@users.noreply.github.com>

backend/internal/repository/finance.go

@@ -387,7 +387,9 @@ func (r *Repository) BillingUsage(orderID string) (*BillingUsage, error) {
 
 func billingUsage(db *gorm.DB, orderID string) (*BillingUsage, error) {
 	var log model.ApiCallLog
-	err := db.Where("billing_order_id = ? AND billable = ? AND status = ? AND usage_available = ?", orderID, true, model.ApiCallStatusSucceeded, true).
+	// 异步视频的真实 usage 由非计费的轮询请求返回；订单本身已经限定了归属，
+	// 结算应读取同订单最新的成功 usage，而不是只看创建请求。
+	err := db.Where("billing_order_id = ? AND status = ? AND usage_available = ?", orderID, model.ApiCallStatusSucceeded, true).
 		Order("created_at desc").First(&log).Error
 	if errors.Is(err, gorm.ErrRecordNotFound) {
 		return nil, ErrBillingUsageUnavailable
@@ -615,6 +617,9 @@ func tokenUsageAmount(order model.BillingOrder, usage *BillingUsage) (int64, err
 	if usage == nil {
 		return 0, ErrBillingUsageUnavailable
 	}
+	if order.Capability == "video" && usage.OutputTokens <= 0 {
+		return 0, ErrBillingUsageUnavailable
+	}
 	input := usage.InputTokens - usage.CachedTokens
 	if input < 0 {
 		input = 0

backend/internal/repository/finance_token_test.go

@@ -0,0 +1,101 @@
+package repository
+
+import (
+	"errors"
+	"testing"
+
+	"infinite-canvas/backend/internal/model"
+
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+)
+
+func TestTokenUsageAmountSettlesArkVideoCompletionTokens(t *testing.T) {
+	amount, err := tokenUsageAmount(model.BillingOrder{
+		Capability:                   "video",
+		OutputTokenPriceMicrocredits: 16_000_000,
+		MultiplierBasisPoints:        10_000,
+	}, &BillingUsage{OutputTokens: 108900})
+	if err != nil {
+		t.Fatalf("tokenUsageAmount() error = %v", err)
+	}
+	if amount != 1_742_400 {
+		t.Fatalf("tokenUsageAmount() = %d", amount)
+	}
+}
+
+func TestBillingUsageReadsAsyncVideoPollUsage(t *testing.T) {
+	db, err := gorm.Open(sqlite.Open("file:finance-token-poll?mode=memory&cache=shared"), &gorm.Config{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := db.AutoMigrate(&model.ApiCallLog{}); err != nil {
+		t.Fatal(err)
+	}
+	if err := db.Create(&model.ApiCallLog{
+		ID: "poll-log-1", BillingOrderID: "order-1", RequestKind: "poll", Billable: false,
+		Status: model.ApiCallStatusSucceeded, UsageAvailable: true, OutputTokens: 108900,
+	}).Error; err != nil {
+		t.Fatal(err)
+	}
+	usage, err := billingUsage(db, "order-1")
+	if err != nil {
+		t.Fatalf("billingUsage() error = %v", err)
+	}
+	if usage.OutputTokens != 108900 {
+		t.Fatalf("billingUsage() = %#v", usage)
+	}
+}
+
+func TestTokenUsageAmountRejectsVideoWithoutOutputUsage(t *testing.T) {
+	_, err := tokenUsageAmount(model.BillingOrder{Capability: "video", OutputTokenPriceMicrocredits: 16_000_000, MultiplierBasisPoints: 10_000}, &BillingUsage{})
+	if !errors.Is(err, ErrBillingUsageUnavailable) {
+		t.Fatalf("tokenUsageAmount() error = %v", err)
+	}
+}
+
+func TestSettleArkVideoTokenOrderFromPollUsage(t *testing.T) {
+	db, err := gorm.Open(sqlite.Open("file:finance-token-settle?mode=memory&cache=shared"), &gorm.Config{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := db.AutoMigrate(&model.CreditAccount{}, &model.BillingOrder{}, &model.ApiCallLog{}, &model.CreditLedgerEntry{}); err != nil {
+		t.Fatal(err)
+	}
+	const reserved = int64(1_916_640)
+	if err := db.Create(&model.CreditAccount{UserID: "user-1", ReservedMicrocredits: reserved}).Error; err != nil {
+		t.Fatal(err)
+	}
+	if err := db.Create(&model.BillingOrder{
+		ID: "order-1", UserID: "user-1", IdempotencyKey: "task:task-1", Capability: "video", BillingMode: "token",
+		AmountMicrocredits: reserved, ReservedAmountMicrocredits: reserved, OutputTokenPriceMicrocredits: 16_000_000,
+		MultiplierBasisPoints: 10_000, Status: model.BillingStatusRunning,
+	}).Error; err != nil {
+		t.Fatal(err)
+	}
+	if err := db.Create(&model.ApiCallLog{
+		ID: "poll-log-1", BillingOrderID: "order-1", RequestKind: "poll", Billable: false,
+		Status: model.ApiCallStatusSucceeded, UsageAvailable: true, OutputTokens: 108900,
+	}).Error; err != nil {
+		t.Fatal(err)
+	}
+
+	repo := &Repository{db: db}
+	if err := repo.SettleBillingOrder("order-1", "ark-task-1"); err != nil {
+		t.Fatalf("SettleBillingOrder() error = %v", err)
+	}
+	var order model.BillingOrder
+	if err := db.First(&order, "id = ?", "order-1").Error; err != nil {
+		t.Fatal(err)
+	}
+	if order.Status != model.BillingStatusSettled || order.ActualAmountMicrocredits != 1_742_400 || order.RefundedAmountMicrocredits != 174_240 {
+		t.Fatalf("settled order = %#v", order)
+	}
+	var account model.CreditAccount
+	if err := db.First(&account, "user_id = ?", "user-1").Error; err != nil {
+		t.Fatal(err)
+	}
+	if account.AvailableMicrocredits != 174_240 || account.ReservedMicrocredits != 0 {
+		t.Fatalf("settled account = %#v", account)
+	}
+}