Booking and pricing related updates

apps/edr-passenger-api/src/modules/fare-engine/fare-engine.service.ts

@@ -32,20 +32,59 @@ export class FareEngineService {
       s => s.sequence > originStop.sequence && s.sequence <= destStop.sequence,
     );
 
-    const missingDistance = legStops.filter(s => s.distanceKm === null || s.distanceKm === undefined);
-    if (missingDistance.length > 0)
-      throw new BadRequestException(
-        `Missing distanceKm on route stops at sequences: ${missingDistance.map(s => s.sequence).join(', ')}`,
-      );
-
-    const totalDistanceKm = legStops.reduce((sum, s) => sum + (s.distanceKm ?? 0), 0);
-
     const seatClass = await this.prisma.seatClass.findUnique({ where: { id: dto.seatClassId } });
     if (!seatClass) throw new NotFoundException('Seat class not found');
     if (!seatClass.isActive) throw new BadRequestException('Seat class is not active');
 
-    const ratePerKmMinor = seatClass.baseFareMinor;
-    const baseFarePerPassengerMinor = totalDistanceKm * ratePerKmMinor;
+    // Resolve fare: FareRule (schedule-scoped → route-scoped) takes precedence over distance×rate
+    const now = new Date();
+    const [originStation, destStation] = await Promise.all([
+      this.prisma.station.findUnique({ where: { id: dto.originStationId } }),
+      this.prisma.station.findUnique({ where: { id: dto.destinationStationId } }),
+    ]);
+    const segmentRoute = originStation && destStation
+      ? `${originStation.code}-${destStation.code}` : null;
+    const fullRoute = `${route.code}`;
+
+    const fareRuleCandidates = await this.prisma.fareRule.findMany({
+      where: {
+        seatClassId: dto.seatClassId,
+        validFrom: { lte: now },
+        OR: [{ validUntil: null }, { validUntil: { gte: now } }],
+      },
+    });
+
+    const fareRule = this.pickBestFareRule(
+      fareRuleCandidates,
+      dto.scheduleId,
+      segmentRoute,
+      fullRoute,
+      dto.nationality,
+    );
+
+    let baseFarePerPassengerMinor: number;
+    let ratePerKmMinor: number;
+    let totalDistanceKm: number;
+    let fareSource: string;
+
+    if (fareRule) {
+      // Flat fare from FareRule — distance is informational only
+      baseFarePerPassengerMinor = fareRule.baseFareMinor;
+      totalDistanceKm = legStops.reduce((sum, s) => sum + (s.distanceKm ?? 0), 0);
+      ratePerKmMinor = totalDistanceKm > 0 ? Math.round(baseFarePerPassengerMinor / totalDistanceKm) : 0;
+      fareSource = fareRule.tripId ? 'SCHEDULE_FARE_RULE' : 'ROUTE_FARE_RULE';
+    } else {
+      // Distance × rate fallback
+      const missingDistance = legStops.filter(s => s.distanceKm === null || s.distanceKm === undefined);
+      if (missingDistance.length > 0)
+        throw new BadRequestException(
+          `Missing distanceKm on route stops at sequences: ${missingDistance.map(s => s.sequence).join(', ')}`,
+        );
+      totalDistanceKm = legStops.reduce((sum, s) => sum + (s.distanceKm ?? 0), 0);
+      ratePerKmMinor = seatClass.baseFareMinor;
+      baseFarePerPassengerMinor = totalDistanceKm * ratePerKmMinor;
+      fareSource = 'DISTANCE_RATE';
+    }
 
     // Premium and insurance fees applied per passenger
     const premiumPerPassenger = seatClass.premiumMinor ?? 0;
@@ -84,11 +123,6 @@ export class FareEngineService {
     const exchangeRate    = await this.currencyService.getExchangeRate(Currency.ETB, billingCurrency);
     const totalInBillingCurrency = Math.round(totalEtbMinor * exchangeRate);
 
-    const [originStation, destStation] = await Promise.all([
-      this.prisma.station.findUnique({ where: { id: dto.originStationId } }),
-      this.prisma.station.findUnique({ where: { id: dto.destinationStationId } }),
-    ]);
-
     const calculation = [
       `Distance:       ${totalDistanceKm} km (${originStation?.name} → ${destStation?.name})`,
       `Rate per km:    ${ratePerKmMinor} ETB minor (${seatClass.name})`,
@@ -110,9 +144,11 @@ export class FareEngineService {
       `Nationality:    ${dto.nationality ?? 'unspecified'} → ${billingCurrency}`,
       `Exchange rate:  1 ETB = ${exchangeRate} ${billingCurrency}`,
       `Total (${billingCurrency}): ${totalInBillingCurrency} ${billingCurrency} minor`,
+      `Fare source:    ${fareSource}`,
     ].join('\n');
 
     return {
+      fareSource,
       routeCode: route.code,
       originName: originStation?.name ?? dto.originStationId,
       destinationName: destStation?.name ?? dto.destinationStationId,
@@ -161,6 +197,37 @@ export class FareEngineService {
     return results.filter(Boolean);
   }
 
+  private pickBestFareRule(
+    candidates: any[],
+    scheduleId?: string,
+    segmentRoute?: string | null,
+    fullRoute?: string,
+    nationality?: string,
+  ): any | null {
+    const nat = nationality ?? null;
+    const priorities = [
+      { tripId: scheduleId, route: segmentRoute, nationality: nat },
+      { tripId: scheduleId, route: segmentRoute, nationality: null },
+      { tripId: scheduleId, route: fullRoute,    nationality: nat },
+      { tripId: scheduleId, route: fullRoute,    nationality: null },
+      { tripId: scheduleId, route: null,         nationality: nat },
+      { tripId: scheduleId, route: null,         nationality: null },
+      { tripId: null,       route: segmentRoute, nationality: nat },
+      { tripId: null,       route: segmentRoute, nationality: null },
+      { tripId: null,       route: fullRoute,    nationality: nat },
+      { tripId: null,       route: fullRoute,    nationality: null },
+      { tripId: null,       route: null,         nationality: nat },
+      { tripId: null,       route: null,         nationality: null },
+    ];
+    for (const p of priorities) {
+      const match = candidates.find(
+        c => c.tripId === p.tripId && c.route === p.route && c.nationality === p.nationality,
+      );
+      if (match) return match;
+    }
+    return null;
+  }
+
   async calculateForSchedule(scheduleId: string, seatClassId: string, nationality?: string) {
     const schedule = await this.prisma.trainSchedule.findUnique({
       where: { id: scheduleId },
@@ -175,6 +242,7 @@ export class FareEngineService {
       destinationStationId: schedule.destinationStationId,
       seatClassId,
       nationality,
+      scheduleId,
     });
   }
 
@@ -199,6 +267,7 @@ export class FareEngineService {
             destinationStationId: schedule.destinationStationId,
             seatClassId: sc.id,
             nationality,
+            scheduleId,
           }).catch(() => null),
         ),
       );