add yard distances management to rule engine

- Introduced new yard distances resource with CRUD operations.
- Created migration for yard distances table with necessary constraints.
- Implemented service and repository for yard distances handling.
- Added controller for API endpoints to manage yard distances.
- Updated rule engine configuration to include yard distances.
- Enhanced rule engine resource page to support yard distance selection.
- Updated contracts and train builder pages to handle new yard distance logic.
- Added error handling utility for better error message extraction.

apps/edr-freight-api/src/modules/routes/dto/create-route.dto.ts

@@ -4,25 +4,22 @@ import {
   ArrayMinSize,
   IsArray,
   IsEnum,
-  IsNumber,
   IsOptional,
   IsUUID,
-  Min,
   ValidateNested,
 } from 'class-validator';
 
 import { RouteStatus } from '../entities/route.entity';
 
+/**
+ * Segment distances are no longer part of the payload — they are resolved
+ * from the configured yard_distances table (Configuration → Yard Distances)
+ * and snapshotted onto route_milestones at create/update.
+ */
 export class CreateRouteMilestoneDto {
   @ApiProperty({ format: 'uuid' })
   @IsUUID()
   yardId!: string;
-
-  @ApiPropertyOptional({ description: 'Km from the previous stop (0 for origin)' })
-  @IsOptional()
-  @IsNumber()
-  @Min(0)
-  distanceKm?: number;
 }
 
 export class CreateRouteDto {

apps/edr-freight-api/src/modules/routes/routes.service.ts

@@ -9,6 +9,7 @@ import { DataSource, In } from 'typeorm';
 
 import { deriveTradeDirection } from '../../common/derive-trade-direction.util';
 import { Yard } from '../rule-engine/entities/yard.entity';
+import { YardDistance } from '../rule-engine/entities/yard-distance.entity';
 import { TrainSchedule } from '../train-schedules/entities/train-schedule.entity';
 import { CreateRouteDto } from './dto/create-route.dto';
 import { FilterRoutesDto } from './dto/filter-routes.dto';
@@ -17,6 +18,9 @@ import { RouteMilestone } from './entities/route-milestone.entity';
 import { formatRouteLabel, Route } from './entities/route.entity';
 import { RoutesRepository } from './routes.repository';
 
+/** Order-insensitive key: distances are symmetric. */
+const pairKey = (a: string, b: string): string => (a < b ? `${a}|${b}` : `${b}|${a}`);
+
 @Injectable()
 export class RoutesService {
   constructor(
@@ -183,47 +187,63 @@ export class RoutesService {
     return this.findById(id);
   }
 
-  private async validateMilestones(
-    milestones: Array<{ yardId: string; distanceKm?: number }>,
-  ) {
+  private async validateMilestones(milestones: Array<{ yardId: string }>) {
     if (milestones.length < 2) {
       throw new BadRequestException('A route requires at least two yards');
     }
 
-    const normalized = milestones.map((milestone, index) => {
-      const distanceKm =
-        index === 0 ? 0 : milestone.distanceKm != null ? milestone.distanceKm : null;
-      if (index > 0 && (distanceKm == null || distanceKm < 0)) {
-        throw new BadRequestException(
-          `Enter segment KM for stop ${index + 1} (from previous yard).`,
-        );
-      }
-      return {
-        yardId: milestone.yardId,
-        sequenceNo: index + 1,
-        distanceKm,
-      };
-    });
-
-    const uniqueYardIds = [...new Set(normalized.map((milestone) => milestone.yardId))];
+    const uniqueYardIds = [...new Set(milestones.map((milestone) => milestone.yardId))];
     const yards = await this.dataSource
       .getRepository(Yard)
       .find({ where: uniqueYardIds.map((id) => ({ id })) });
     const yardIds = new Set(yards.map((yard) => yard.id));
 
-    for (const milestone of normalized) {
+    for (const milestone of milestones) {
       if (!yardIds.has(milestone.yardId)) {
         throw new BadRequestException(`Yard ${milestone.yardId} does not exist`);
       }
     }
 
-    if (normalized[0].yardId === normalized[normalized.length - 1].yardId) {
+    if (milestones[0].yardId === milestones[milestones.length - 1].yardId) {
       throw new BadRequestException('Origin and destination yards must be different');
     }
 
-    const originYardId = normalized[0].yardId;
-    const destinationYardId = normalized[normalized.length - 1].yardId;
     const yardById = new Map(yards.map((yard) => [yard.id, yard]));
+    const distanceByPair = await this.loadDistanceLookup(uniqueYardIds);
+
+    // Segment km come from the configured yard-distance table, not the payload
+    // — a route can only be built over pairs an admin has entered. Distances
+    // are symmetric, so an A→B row also serves B→A.
+    const missingPairs: string[] = [];
+    const normalized = milestones.map((milestone, index) => {
+      if (index === 0) {
+        return { yardId: milestone.yardId, sequenceNo: 1, distanceKm: 0 };
+      }
+      const previousYardId = milestones[index - 1].yardId;
+      const distanceKm = distanceByPair.get(pairKey(previousYardId, milestone.yardId));
+      if (distanceKm == null) {
+        const from = yardById.get(previousYardId);
+        const to = yardById.get(milestone.yardId);
+        missingPairs.push(
+          `${from?.label ?? previousYardId} ↔ ${to?.label ?? milestone.yardId}`,
+        );
+      }
+      return {
+        yardId: milestone.yardId,
+        sequenceNo: index + 1,
+        distanceKm: distanceKm ?? null,
+      };
+    });
+
+    if (missingPairs.length > 0) {
+      throw new BadRequestException(
+        `No distance configured for: ${missingPairs.join(', ')}. ` +
+          'Add the missing yard distances in Configuration → Yard Distances first.',
+      );
+    }
+
+    const originYardId = milestones[0].yardId;
+    const destinationYardId = milestones[milestones.length - 1].yardId;
     const direction = deriveTradeDirection(
       yardById.get(originYardId) ?? { country: null },
       yardById.get(destinationYardId) ?? { country: null },
@@ -236,4 +256,17 @@ export class RoutesService {
       milestones: normalized,
     };
   }
+
+  /** Order-insensitive pair → km map over every configured distance touching the yards. */
+  private async loadDistanceLookup(yardIds: string[]): Promise<Map<string, number>> {
+    const rows = await this.dataSource
+      .getRepository(YardDistance)
+      .find({ where: [{ fromYardId: In(yardIds) }, { toYardId: In(yardIds) }] });
+
+    const lookup = new Map<string, number>();
+    for (const row of rows) {
+      lookup.set(pairKey(row.fromYardId, row.toYardId), Number(row.distanceKm));
+    }
+    return lookup;
+  }
 }