优化

src/modules/first-leg/utils/priceEstimate.test.mjs

@@ -0,0 +1,34 @@
+import assert from 'node:assert/strict'
+import test from 'node:test'
+import { createPriceEstimateBreakdown } from './priceEstimate.ts'
+
+test('explains KG estimates and selects volume weight when it is larger', () => {
+  assert.deepEqual(createPriceEstimateBreakdown(16, 0.6, 'KG'), {
+    actualLabel: '实际毛重',
+    actualQuantity: 16,
+    convertedLabel: '体积重量',
+    convertedQuantity: 100.2,
+    convertedFormula: '0.6 m³ × 167',
+    chargeableLabel: '计费重量',
+    basisLabel: '采用体积重量',
+  })
+})
+
+test('explains CBM estimates and selects the larger converted quantity', () => {
+  const result = createPriceEstimateBreakdown(400, 1, 'CBM')
+
+  assert.equal(result?.actualLabel, '实际体积')
+  assert.equal(result?.convertedLabel, '重量折算体积')
+  assert.equal(result?.convertedQuantity, 400 / 363)
+  assert.equal(result?.convertedFormula, '400 KG ÷ 363')
+  assert.equal(result?.chargeableLabel, '计费体积')
+  assert.equal(result?.basisLabel, '采用重量折算体积')
+})
+
+test('does not invent an explanation for an unsupported charge unit', () => {
+  assert.equal(createPriceEstimateBreakdown(16, 0.6, 'PALLET'), null)
+})
+
+test('keeps floating point artifacts out of the displayed formula', () => {
+  assert.equal(createPriceEstimateBreakdown(16, 0.1 + 0.2, 'KG')?.convertedFormula, '0.3 m³ × 167')
+})

src/modules/first-leg/utils/priceEstimate.ts

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+const KG_PER_CBM = 167
+const KG_PER_BILLABLE_CBM = 363
+
+function formatFormulaNumber(value: number) {
+  return value.toLocaleString('zh-CN', { maximumFractionDigits: 6, useGrouping: false })
+}
+
+export interface PriceEstimateBreakdown {
+  actualLabel: string
+  actualQuantity: number
+  convertedLabel: string
+  convertedQuantity: number
+  convertedFormula: string
+  chargeableLabel: string
+  basisLabel: string
+}
+
+/**
+ * Explains the server's current first-leg chargeable-quantity rules. The server
+ * response remains authoritative for the final chargeable quantity and amount.
+ */
+export function createPriceEstimateBreakdown(
+  actualWeightKg: number,
+  actualVolumeCbm: number,
+  chargeUnit: string,
+): PriceEstimateBreakdown | null {
+  if (chargeUnit === 'KG') {
+    const volumeWeightKg = actualVolumeCbm * KG_PER_CBM
+    return {
+      actualLabel: '实际毛重',
+      actualQuantity: actualWeightKg,
+      convertedLabel: '体积重量',
+      convertedQuantity: volumeWeightKg,
+      convertedFormula: `${formatFormulaNumber(actualVolumeCbm)} m³ × ${KG_PER_CBM}`,
+      chargeableLabel: '计费重量',
+      basisLabel: actualWeightKg >= volumeWeightKg ? '采用实际毛重' : '采用体积重量',
+    }
+  }
+
+  if (chargeUnit === 'CBM') {
+    const convertedVolumeCbm = actualWeightKg / KG_PER_BILLABLE_CBM
+    return {
+      actualLabel: '实际体积',
+      actualQuantity: actualVolumeCbm,
+      convertedLabel: '重量折算体积',
+      convertedQuantity: convertedVolumeCbm,
+      convertedFormula: `${formatFormulaNumber(actualWeightKg)} KG ÷ ${KG_PER_BILLABLE_CBM}`,
+      chargeableLabel: '计费体积',
+      basisLabel: actualVolumeCbm >= convertedVolumeCbm ? '采用实际体积' : '采用重量折算体积',
+    }
+  }
+
+  return null
+}