Fare engine added

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

@@ -0,0 +1,65 @@
+import { Body, Controller, Post, Get, Query } from '@nestjs/common';
+import { ApiTags, ApiOperation, ApiQuery, ApiResponse } from '@nestjs/swagger';
+import { FareEngineService } from './fare-engine.service';
+import { FareCalculateDto, FareBreakdownDto } from './fare-engine.dto';
+
+@ApiTags('Fare Engine')
+@Controller('fare-engine')
+export class FareEngineController {
+  constructor(private service: FareEngineService) {}
+
+  @Post('calculate')
+  @ApiOperation({
+    summary: 'Calculate fare for a journey leg',
+    description: `Computes fare using the formula:
+
+**Fare = totalKm × ratePerKm × exchangeRate**
+
+- \`totalKm\` — sum of \`distanceKm\` on RouteStop records between origin and destination
+- \`ratePerKm\` — \`SeatClass.basePrice\` (stored in ETB minor units per km)
+- \`exchangeRate\` — derived from passenger nationality:
+  - **Ethiopian** → ETB (rate = 1.0)
+  - **Djiboutian** → DJF (rate ≈ 3.25)
+  - **Other / unspecified** → USD (rate ≈ 0.018)
+
+Age-based pricing: first child (age < 5) travels free, subsequent children pay full fare.
+5% tax applied after promo discount.
+Returns a full breakdown including a human-readable calculation trace.`,
+  })
+  @ApiResponse({ status: 201, type: FareBreakdownDto, description: 'Full fare breakdown with calculation trace' })
+  @ApiResponse({ status: 400, description: 'Invalid route/station combination or missing distanceKm on route stops' })
+  @ApiResponse({ status: 404, description: 'Route or seat class not found' })
+  calculate(@Body() dto: FareCalculateDto) {
+    return this.service.calculate(dto);
+  }
+
+  @Get('compare')
+  @ApiOperation({
+    summary: 'Compare fares across all seat classes for a route leg',
+    description: 'Returns fare breakdown for every active seat class on the requested leg. Useful for rendering a class-selection table on the booking screen.',
+  })
+  @ApiQuery({ name: 'routeId', description: 'Route UUID' })
+  @ApiQuery({ name: 'originStationId', description: 'Origin station UUID' })
+  @ApiQuery({ name: 'destinationStationId', description: 'Destination station UUID' })
+  @ApiQuery({ name: 'nationality', required: false, description: 'Passenger nationality (Ethiopian | Djiboutian | other). Determines billing currency.' })
+  @ApiQuery({ name: 'adultCount', required: false, type: Number, description: 'Number of adults (default 1)' })
+  @ApiQuery({ name: 'childCount', required: false, type: Number, description: 'Number of children (default 0)' })
+  @ApiResponse({ status: 200, description: 'Array of fare breakdowns, one per active seat class, ordered by price ascending' })
+  compareClasses(
+    @Query('routeId') routeId: string,
+    @Query('originStationId') originStationId: string,
+    @Query('destinationStationId') destinationStationId: string,
+    @Query('nationality') nationality?: string,
+    @Query('adultCount') adultCount?: string,
+    @Query('childCount') childCount?: string,
+  ) {
+    return this.service.compareClasses(
+      routeId,
+      originStationId,
+      destinationStationId,
+      nationality,
+      adultCount ? parseInt(adultCount) : 1,
+      childCount ? parseInt(childCount) : 0,
+    );
+  }
+}