feat(*): 模型计费与渠道目录 - 支持视频 Token 报价结算和稳定模型展示

backend/internal/kernel/token_billing.go

@@ -0,0 +1,41 @@
+package kernel
+
+import (
+	"errors"
+	"math/big"
+)
+
+var (
+	ErrInvalidTokenBilling  = errors.New("invalid token billing parameters")
+	ErrTokenBillingOverflow = errors.New("token billing amount overflows int64")
+)
+
+type TokenBillingTerm struct {
+	Tokens            int64
+	PriceMicrocredits int64
+}
+
+// TokenBillingAmount 按每百万 Token 单价及万分比倍率汇总费用，只对最终微积分金额上取整。
+func TokenBillingAmount(multiplierBPS int64, terms ...TokenBillingTerm) (int64, error) {
+	if multiplierBPS <= 0 {
+		return 0, ErrInvalidTokenBilling
+	}
+	var total, product big.Int
+	for _, term := range terms {
+		if term.Tokens < 0 || term.PriceMicrocredits < 0 {
+			return 0, ErrInvalidTokenBilling
+		}
+		product.Mul(big.NewInt(term.Tokens), big.NewInt(term.PriceMicrocredits))
+		total.Add(&total, &product)
+	}
+	total.Mul(&total, big.NewInt(multiplierBPS))
+	var remainder big.Int
+	total.QuoRem(&total, big.NewInt(10_000_000_000), &remainder)
+	if remainder.Sign() != 0 {
+		total.Add(&total, big.NewInt(1))
+	}
+	if !total.IsInt64() {
+		return 0, ErrTokenBillingOverflow
+	}
+	return total.Int64(), nil
+}