fix issue

apps/edr-freight-api/src/modules/rule-engine/services/rates.duplicate-pattern.spec.ts

@@ -0,0 +1,138 @@
+import { ConflictException } from '@nestjs/common';
+
+import { RatesService } from './rates.service';
+import type { Rate } from '../entities/rate.entity';
+
+/**
+ * One rate per lane + scope, whatever the unit.
+ *
+ * Pricing resolves a single rate for a (type, container type, leg) and then
+ * applies whatever unit it carries — it has no way to choose between a
+ * per-container and a per-wagon row for the same 20ft lane, and used to bill
+ * whichever the database happened to return first. So the unit is NOT part of a
+ * rate's identity: changing how a lane is billed means editing its rate.
+ */
+describe('RatesService — one rate per pattern', () => {
+  const DJ = '11111111-1111-4000-8000-000000000001';
+  const ET = '11111111-1111-4000-8000-000000000002';
+  const CT20 = '11111111-1111-4000-8000-000000000003';
+
+  const existing = (over: Partial<Rate> = {}): Rate =>
+    ({
+      id: 'rate-existing',
+      rateType: 'CONTAINER_IMPORT',
+      rateUnit: 'PER_WAGON',
+      rateValue: 1690,
+      containerTypeId: CT20,
+      cargoTypeId: null,
+      tradeDirection: 'IMPORT',
+      originYardId: DJ,
+      destinationYardId: ET,
+      status: 'LIVE',
+      ...over,
+    }) as Rate;
+
+  const dto = {
+    appliesTo: 'CONTAINER',
+    trigger: 'ALWAYS',
+    tradeDirection: 'IMPORT',
+    containerTypeId: CT20,
+    originYardId: DJ,
+    destinationYardId: ET,
+    rateValue: 845,
+    rateUnit: 'PER_CONTAINER',
+  };
+
+  let repository: { findByPattern: jest.Mock; create: jest.Mock };
+  let service: RatesService;
+
+  beforeEach(() => {
+    repository = {
+      findByPattern: jest.fn().mockResolvedValue(null),
+      create: jest.fn(async (r) => ({ id: 'rate-new', ...r })),
+    };
+    service = new RatesService(
+      repository as never,
+      {
+        findById: jest.fn(async (id: string) => ({
+          id,
+          country: id === DJ ? 'Djibouti' : 'Ethiopia',
+          label: id === DJ ? 'Doraleh' : 'Gelan',
+        })),
+      } as never,
+      { findById: jest.fn().mockResolvedValue(null) } as never,
+    );
+  });
+
+  it('refuses a second rate on the same lane that only differs by unit', async () => {
+    repository.findByPattern.mockResolvedValue(existing());
+
+    await expect(service.create(dto as never, 'staff-1')).rejects.toBeInstanceOf(
+      ConflictException,
+    );
+    expect(repository.create).not.toHaveBeenCalled();
+  });
+
+  it('looks the pattern up without the unit, so either order collides', async () => {
+    await service.create(dto as never, 'staff-1');
+
+    const pattern = repository.findByPattern.mock.calls[0][0];
+    expect(pattern).not.toHaveProperty('rateUnit');
+    expect(pattern).toMatchObject({
+      rateType: 'CONTAINER_IMPORT',
+      containerTypeId: CT20,
+      originYardId: DJ,
+      destinationYardId: ET,
+    });
+  });
+
+  it('still allows the same unit on a different lane', async () => {
+    await service.create(dto as never, 'staff-1');
+    expect(repository.create).toHaveBeenCalledWith(
+      expect.objectContaining({
+        rateUnit: 'PER_CONTAINER',
+        rateValue: 845,
+        status: 'DRAFT',
+      }),
+    );
+  });
+
+  /**
+   * Additive surcharges are billed per matching rate, each by its own unit, so
+   * hazard is legitimately per-container for boxes AND per-ton for bulk. The
+   * unit stays part of their identity or the second one could never be created.
+   */
+  it('keeps the unit in the key for an additive surcharge', async () => {
+    await service.create(
+      {
+        appliesTo: 'OTHER',
+        trigger: 'HAZARDOUS',
+        rateValue: 300,
+        rateUnit: 'PER_CONTAINER',
+      } as never,
+      'staff-1',
+    );
+
+    expect(repository.findByPattern.mock.calls[0][0]).toMatchObject({
+      rateType: 'HAZARD_SURCHARGE',
+      rateUnit: 'PER_CONTAINER',
+    });
+  });
+
+  it('treats lashing as singly resolved — one unit per direction', async () => {
+    await service.create(
+      {
+        appliesTo: 'OTHER',
+        trigger: 'LASHING',
+        tradeDirection: 'IMPORT',
+        rateValue: 40,
+        rateUnit: 'PER_TON',
+      } as never,
+      'staff-1',
+    );
+
+    expect(repository.findByPattern.mock.calls[0][0]).not.toHaveProperty(
+      'rateUnit',
+    );
+  });
+});

apps/edr-freight-api/src/modules/rule-engine/services/rates.service.ts

@@ -132,6 +132,24 @@ export class RatesService {
     );
   }
 
+  /**
+   * True when pricing resolves exactly ONE rate for this shape (base freight,
+   * customs clearance, lashing, empty-container return — all `find()`-based
+   * lookups). For those the unit is not part of the rate's identity: two rows
+   * for the same lane differing only by unit are a duplicate the engine cannot
+   * choose between.
+   *
+   * The additive surcharges are the opposite — the engine bills EVERY matching
+   * rate by its own unit, which is how hazard can be per-container for boxes
+   * and per-ton for bulk at the same time — so their unit stays part of the key.
+   */
+  private resolvesSingleRate(
+    appliesTo: Rate['appliesTo'],
+    trigger: Rate['trigger'],
+  ): boolean {
+    return this.isRouteScoped(appliesTo, trigger) || trigger === 'LASHING';
+  }
+
   /**
    * Which country each end of the leg must sit in, given what the rate is for.
    * The railway only sells three shapes: import lands at the Djibouti ports and
@@ -326,10 +344,17 @@ export class RatesService {
    * Reject a second rate with the same identity pattern (rateType + scope). With
    * effective-date windows gone, two LIVE/DRAFT rates for the same pattern would
    * make pricing ambiguous — so we allow exactly one per pattern.
+   *
+   * The UNIT is not part of that identity. Pricing resolves one rate per lane +
+   * scope and then applies whatever unit it carries; a per-container and a
+   * per-wagon row for the same 20ft lane are two answers to one question, and
+   * the engine silently picked one of them. Changing how a lane is billed means
+   * editing its rate, not adding a second.
    */
   private async assertNoDuplicatePattern(pattern: {
     rateType: string;
-    rateUnit: string;
+    /** Passed only for additive surcharges — see {@link resolvesSingleRate}. */
+    rateUnit?: string;
     containerTypeId: string | null;
     cargoTypeId: string | null;
     tradeDirection: string | null;
@@ -415,7 +440,7 @@ export class RatesService {
 
     await this.assertNoDuplicatePattern({
       rateType,
-      rateUnit,
+      ...(this.resolvesSingleRate(appliesTo, trigger) ? {} : { rateUnit }),
       containerTypeId,
       cargoTypeId,
       tradeDirection,
@@ -600,7 +625,7 @@ export class RatesService {
     // Guard the pattern uniqueness for the new identity, ignoring this row.
     await this.assertNoDuplicatePattern({
       rateType,
-      rateUnit,
+      ...(this.resolvesSingleRate(appliesTo, trigger) ? {} : { rateUnit }),
       containerTypeId: updates.containerTypeId,
       cargoTypeId: updates.cargoTypeId,
       tradeDirection: updates.tradeDirection,