fix rate edit

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

@@ -119,12 +119,62 @@ export class RatesService {
     });
   }
 
-  /** Update a DRAFT rate. */
+  /**
+   * Update a DRAFT rate in place. Nothing prices off a draft, so a direct edit
+   * is safe. A LIVE rate cannot take this path — see `applyApprovedUpdate`.
+   */
   async update(id: string, dto: UpdateRateDto): Promise<Rate> {
     const existing = await this.findById(id);
     if (existing.status !== 'DRAFT') {
-      throw new BadRequestException('Only DRAFT rates can be updated');
+      throw new BadRequestException(
+        existing.status === 'LIVE'
+          ? 'A LIVE rate cannot be edited directly — file a rate change request so an approver can apply it.'
+          : 'Only DRAFT rates can be updated',
+      );
     }
+    return this.applyUpdate(existing, dto);
+  }
+
+  /**
+   * Apply an approved change request to a LIVE rate. Same validation as a
+   * DRAFT edit — it just skips the DRAFT guard, because a LIVE rate reaching
+   * here has already been through approval. Only ever called by
+   * RateChangeRequestsService.approve.
+   */
+  async applyApprovedUpdate(id: string, dto: UpdateRateDto): Promise<Rate> {
+    const existing = await this.findById(id);
+    if (existing.status !== 'LIVE') {
+      throw new BadRequestException(
+        `Rate change requests apply to LIVE rates only — this rate is ${existing.status}.`,
+      );
+    }
+    return this.applyUpdate(existing, dto);
+  }
+
+  /**
+   * Validate a proposed patch against a rate without writing anything — lets a
+   * change request be refused at submit time instead of surprising the
+   * approver. Throws exactly what applying it would throw.
+   */
+  async assertUpdateValid(id: string, dto: UpdateRateDto): Promise<void> {
+    await this.buildUpdate(await this.findById(id), dto);
+  }
+
+  private async applyUpdate(existing: Rate, dto: UpdateRateDto): Promise<Rate> {
+    const updates = await this.buildUpdate(existing, dto);
+    const updated = await this.repository.update(existing.id, updates);
+    if (!updated) throw new NotFoundException(`Rate ${existing.id} not found`);
+    return updated;
+  }
+
+  /**
+   * The shared edit body: re-derives rateType, re-validates the unit against
+   * the (possibly changed) shape, and guards pattern uniqueness. Status is
+   * never touched — an approved edit to a LIVE rate stays LIVE. Pure apart
+   * from the uniqueness read, so it doubles as the dry-run validator.
+   */
+  private async buildUpdate(existing: Rate, dto: UpdateRateDto): Promise<Partial<Rate>> {
+    const id = existing.id;
     const updates: Partial<Rate> = {};
 
     const appliesTo = (dto.appliesTo as Rate['appliesTo']) ?? existing.appliesTo;
@@ -179,9 +229,7 @@ export class RatesService {
 
     updates.currency = dto.currency ?? existing.currency ?? 'USD';
     if (dto.rateValue !== undefined) updates.rateValue = dto.rateValue;
-    const updated = await this.repository.update(id, updates);
-    if (!updated) throw new NotFoundException(`Rate ${id} not found`);
-    return updated;
+    return updates;
   }
 
   /** Submit a DRAFT rate for CEO approval. */