feat: enhance tiered billing functionality and UI components

- Introduced new fields for billing mode and expression in the Pricing model.
- Implemented dynamic pricing breakdown component to display tiered billing details.
- Updated various components to support and render tiered billing information.
- Enhanced pricing calculation logic to accommodate dynamic pricing scenarios.
- Added tests for new billing expression functionalities and UI components.

model/pricing.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/QuantumNous/new-api/common"
 	"github.com/QuantumNous/new-api/constant"
+	"github.com/QuantumNous/new-api/setting/billing_setting"
 	"github.com/QuantumNous/new-api/setting/ratio_setting"
 	"github.com/QuantumNous/new-api/types"
 )
@@ -32,6 +33,8 @@ type Pricing struct {
 	AudioCompletionRatio   *float64                `json:"audio_completion_ratio,omitempty"`
 	EnableGroup            []string                `json:"enable_groups"`
 	SupportedEndpointTypes []constant.EndpointType `json:"supported_endpoint_types"`
+	BillingMode            string                  `json:"billing_mode,omitempty"`
+	BillingExpr            string                  `json:"billing_expr,omitempty"`
 	PricingVersion         string                  `json:"pricing_version,omitempty"`
 }
 
@@ -319,6 +322,12 @@ func updatePricing() {
 			audioCompletionRatio := ratio_setting.GetAudioCompletionRatio(model)
 			pricing.AudioCompletionRatio = &audioCompletionRatio
 		}
+		if billingMode := billing_setting.GetBillingMode(model); billingMode == "tiered_expr" {
+			pricing.BillingMode = billingMode
+			if expr, ok := billing_setting.GetBillingExpr(model); ok {
+				pricing.BillingExpr = expr
+			}
+		}
 		pricingMap = append(pricingMap, pricing)
 	}