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edr-platform/apps/edr-freight-api/src/modules/trains/train-builder.service.ts

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31 KiB
TypeScript

import { Freight, WagonMovementKind, WagonStatus } from '@edr/types';
import {
BadRequestException,
ConflictException,
Injectable,
NotFoundException,
} from '@nestjs/common';
import { DataSource, EntityManager, ILike, In } from 'typeorm';
import { Locomotive } from '../locomotives/entities/locomotive.entity';
import { Yard } from '../rule-engine/entities/yard.entity';
import { minLocomotiveLimits } from '../train-scheduling/train-capacity.util';
import { WagonType } from '../wagon-types/entities/wagon-type.entity';
import { WagonMovement } from '../wagons/entities/wagon-movement.entity';
import { Wagon } from '../wagons/entities/wagon.entity';
import { AssignTrainWagonsDto } from './dto/assign-train-wagons.dto';
import { BuildTrainDto } from './dto/build-train.dto';
import { ListBuiltTrainsQueryDto } from './dto/list-built-trains-query.dto';
import { ReorderTrainWagonsDto } from './dto/reorder-train-wagons.dto';
import { UpdateTrainDetailsDto } from './dto/update-train-details.dto';
import { UpdateTrainLocomotivesDto } from './dto/update-train-locomotives.dto';
import { TrainLocomotive } from './entities/train-locomotive.entity';
import { Train } from './entities/train.entity';
import {
buildPaginationMeta,
normalizePagination,
} from '../../common/utils/pagination.util';
const round = (value: unknown) => Math.round((Number(value) || 0) * 100) / 100;
/** The one active (DRAFT/SCHEDULED/DISPATCHED) schedule surfaced per built train. */
export interface ActiveScheduleRef {
id: string;
status: string;
reference: string | null;
direction: string | null;
trainNumber: string | null;
}
/**
* Train Builder — assembles persistent fleet trains (code + 2+ locomotives +
* ordered wagons, all in one yard) that scheduling can later reference as a
* unit instead of hand-picking locomotives per departure.
*
* Resource rules:
* - Locomotive double-use is prevented through the `train_locomotives` link
* table (a locomotive rides at most one built train); its `status` column
* keeps its operational meaning (ASSIGNED = out on a dispatched train).
* - Wagons attached to a train are flipped to ASSIGNED (same semantic the
* legacy assign-train flow uses), so no other train or schedule grabs them.
*/
@Injectable()
export class TrainBuilderService {
constructor(private readonly dataSource: DataSource) {}
async buildTrain(dto: BuildTrainDto) {
const locomotiveIds = [...new Set(dto.locomotiveIds)];
if (locomotiveIds.length < 2) {
throw new BadRequestException('A train must be pulled by at least two locomotives');
}
const trainId = await this.dataSource.transaction(async (manager) => {
const code = await this.generateTrainCode(manager);
// Friendly 409 before the partial unique indexes (the race-proof backstop):
// the typed pair may not collide with any train's pair or legacy number.
const importTrainNumber = dto.importTrainNumber.trim();
const exportTrainNumber = dto.exportTrainNumber.trim();
const numberClash: { code: string }[] = await manager.query(
`SELECT code FROM freight.trains
WHERE deleted_at IS NULL
AND (import_train_number IN ($1, $2)
OR export_train_number IN ($1, $2)
OR train_number IN ($1, $2))
LIMIT 1`,
[importTrainNumber, exportTrainNumber],
);
if (numberClash.length) {
throw new ConflictException(
`Train number ${importTrainNumber}/${exportTrainNumber} is already used by train ${numberClash[0].code}`,
);
}
const yard = await manager.getRepository(Yard).findOne({ where: { id: dto.currentYardId } });
if (!yard) throw new NotFoundException(`Yard ${dto.currentYardId} not found`);
const locomotives = await this.validateAndLockLocomotives(
manager,
locomotiveIds,
yard,
null,
);
// Effective haul capacity is capped by the weakest locomotive in the set.
const limits = minLocomotiveLimits(locomotives);
const train = await manager.getRepository(Train).save(
manager.getRepository(Train).create({
code,
currentYardId: yard.id,
capacityTons: round(limits?.maxPullWeightTons ?? 0),
status: Freight.TrainStatus.Available,
trainName: dto.trainName?.trim() || undefined,
notes: dto.notes?.trim() || undefined,
importTrainNumber,
exportTrainNumber,
}),
);
await this.replaceLocomotiveLinks(manager, train.id, locomotiveIds);
if (dto.wagonIds?.length) {
await this.attachWagons(manager, train, dto.wagonIds, 0);
}
return train.id;
});
return this.getComposition(trainId);
}
/** Paginated builder list with a composition summary per train. */
async listBuilt(query: ListBuiltTrainsQueryDto) {
const { page, pageSize, skip, take } = normalizePagination(query);
const search = query.search?.trim();
const filters = {
...(query.status ? { status: query.status } : {}),
...(query.currentYardId ? { currentYardId: query.currentYardId } : {}),
};
const where = search
? [
{ ...filters, code: ILike(`%${search}%`) },
{ ...filters, trainName: ILike(`%${search}%`) },
]
: filters;
const [trains, total] = await this.dataSource.getRepository(Train).findAndCount({
where,
relations: {
currentYard: true,
locomotives: { locomotive: true },
wagons: { wagonType: true },
},
order: { [query.sortBy ?? 'createdAt']: query.sortOrder ?? 'DESC' },
skip,
take,
});
const activeByTrain = await this.loadActiveScheduleByTrain(trains.map((t) => t.id));
return {
items: trains.map((train) => this.mapSummary(train, activeByTrain.get(train.id) ?? null)),
meta: buildPaginationMeta(total, page, pageSize),
};
}
/**
* One ACTIVE schedule per train for the page (prefer the DISPATCHED run,
* else the earliest upcoming departure) — feeds the list's direction tint
* and in-use train number.
*/
private async loadActiveScheduleByTrain(
trainIds: string[],
): Promise<Map<string, ActiveScheduleRef>> {
if (!trainIds.length) return new Map();
const rows: (ActiveScheduleRef & { trainId: string })[] = await this.dataSource.query(
`SELECT DISTINCT ON (tset.train_id)
tset.train_id AS "trainId",
ts.id,
ts.status,
ts.reference,
ts.direction,
ts.train_number AS "trainNumber"
FROM freight.train_schedules ts
JOIN freight.train_sets tset ON tset.id = ts.train_set_id
WHERE tset.train_id = ANY($1)
AND ts.deleted_at IS NULL
AND ts.status IN ('DRAFT', 'SCHEDULED', 'DISPATCHED')
ORDER BY tset.train_id, (ts.status = 'DISPATCHED') DESC, ts.scheduled_departure_date ASC`,
[trainIds],
);
return new Map(rows.map(({ trainId, ...schedule }) => [trainId, schedule]));
}
/** Full consist: yard, ordered locomotives + wagons, totals vs. haul limits. */
async getComposition(id: string) {
const train = await this.dataSource.getRepository(Train).findOne({
where: { id },
relations: {
currentYard: true,
locomotives: { locomotive: { currentYard: true } },
wagons: { wagonType: true, currentYard: true },
},
order: {
locomotives: { sequenceNo: 'ASC' },
wagons: { sequenceNumber: 'ASC' },
},
});
if (!train) throw new NotFoundException(`Train ${id} not found`);
const schedules: ActiveScheduleRef[] = await this.dataSource.query(
`SELECT ts.id, ts.status, ts.reference, ts.direction,
ts.train_number AS "trainNumber"
FROM freight.train_schedules ts
JOIN freight.train_sets tset ON tset.id = ts.train_set_id
WHERE tset.train_id = $1
AND ts.deleted_at IS NULL
AND ts.status IN ('DRAFT', 'SCHEDULED', 'DISPATCHED')
ORDER BY ts.scheduled_departure_date ASC`,
[id],
);
const locomotives = (train.locomotives ?? [])
.filter((link) => link.locomotive)
.map((link, index) => ({
id: link.locomotive!.id,
code: link.locomotive!.code,
name: link.locomotive!.name ?? null,
locomotiveType: link.locomotive!.locomotiveType,
status: link.locomotive!.status,
sequenceNo: link.sequenceNo,
role: index === 0 ? 'LEAD' : 'ASSIST',
currentYardId: link.locomotive!.currentYardId ?? null,
currentYard: link.locomotive!.currentYard
? {
id: link.locomotive!.currentYard.id,
code: link.locomotive!.currentYard.code,
label: link.locomotive!.currentYard.label,
}
: null,
maxPullWeightTons: round(link.locomotive!.maxPullWeightTons),
maxTrainLengthMeters: round(link.locomotive!.maxTrainLengthMeters),
}));
const wagons = (train.wagons ?? []).map((wagon) => ({
id: wagon.id,
wagonNumber: wagon.wagonNumber,
sequenceNumber: wagon.sequenceNumber,
status: wagon.status,
wagonType: wagon.wagonType
? {
id: wagon.wagonType.id,
code: wagon.wagonType.code,
name: wagon.wagonType.name,
capacityTons: round(wagon.wagonType.capacityTons),
tareWeightTons: round(wagon.wagonType.tareWeightTons),
lengthMeters: round(wagon.wagonType.lengthMeters),
}
: null,
}));
const limits = minLocomotiveLimits(
(train.locomotives ?? [])
.map((link) => link.locomotive)
.filter((loco): loco is Locomotive => Boolean(loco)),
);
const totalTareTons = round(
wagons.reduce((sum, w) => sum + (w.wagonType?.tareWeightTons ?? 0), 0),
);
const totalCapacityTons = round(
wagons.reduce((sum, w) => sum + (w.wagonType?.capacityTons ?? 0), 0),
);
const totalLengthMeters = round(
wagons.reduce((sum, w) => sum + (w.wagonType?.lengthMeters ?? 0), 0),
);
const maxPullWeightTons = round(limits?.maxPullWeightTons ?? 0);
const maxTrainLengthMeters = round(limits?.maxTrainLengthMeters ?? 0);
return {
id: train.id,
code: train.code,
trainName: train.trainName ?? null,
status: train.status,
importTrainNumber: train.importTrainNumber ?? null,
exportTrainNumber: train.exportTrainNumber ?? null,
notes: train.notes ?? null,
createdAt: train.createdAt,
currentYard: train.currentYard
? { id: train.currentYard.id, code: train.currentYard.code, label: train.currentYard.label }
: null,
locomotives,
wagons,
totals: {
wagonCount: wagons.length,
totalTareTons,
// Informational only — building never checks against full capacity;
// the real gross check (cargo + tare vs haul limit) runs at allocation.
totalCapacityTons,
totalLengthMeters,
maxPullWeightTons,
maxTrainLengthMeters,
// Cargo the locomotives can still haul once pulling the empty consist.
payloadCapacityTons: round(Math.max(0, maxPullWeightTons - totalTareTons)),
// Share of the haul limit consumed by the empty wagons alone.
tareUtilizationPct: maxPullWeightTons
? round((totalTareTons / maxPullWeightTons) * 100)
: null,
lengthUtilizationPct: maxTrainLengthMeters
? round((totalLengthMeters / maxTrainLengthMeters) * 100)
: null,
},
activeSchedules: schedules,
// Composition is frozen while the train is out on a dispatched run.
editable: !schedules.some((s) => s.status === 'DISPATCHED'),
};
}
/** Replace the locomotive set (still minimum 2, same-yard rule applies). */
async setLocomotives(id: string, dto: UpdateTrainLocomotivesDto) {
const locomotiveIds = [...new Set(dto.locomotiveIds)];
if (locomotiveIds.length < 2) {
throw new BadRequestException('A train must be pulled by at least two locomotives');
}
await this.dataSource.transaction(async (manager) => {
const train = await this.getEditableTrain(manager, id);
const yard = await manager
.getRepository(Yard)
.findOne({ where: { id: train.currentYardId ?? '' } });
if (!yard) {
throw new BadRequestException('Train has no yard; set the yard before changing locomotives');
}
const locomotives = await this.validateAndLockLocomotives(
manager,
locomotiveIds,
yard,
train.id,
);
await this.replaceLocomotiveLinks(manager, train.id, locomotiveIds);
const limits = minLocomotiveLimits(locomotives);
await manager
.getRepository(Train)
.update(train.id, { capacityTons: round(limits?.maxPullWeightTons ?? 0) });
});
return this.getComposition(id);
}
/**
* Edit a built train's display identity: name and fixed import/export run
* numbers. Mirrors the build-time number rules — the pair may not collide
* with any other train's pair or legacy number (friendly 409 ahead of the
* partial unique indexes). Blocked while the train is out on a dispatched
* run, like every other composition edit.
*/
async updateDetails(id: string, dto: UpdateTrainDetailsDto) {
await this.dataSource.transaction(async (manager) => {
const train = await this.getEditableTrain(manager, id);
const patch: Partial<Train> = {};
if (dto.trainName !== undefined) {
patch.trainName = dto.trainName.trim() || null;
}
const importTrainNumber = dto.importTrainNumber?.trim();
const exportTrainNumber = dto.exportTrainNumber?.trim();
if (importTrainNumber) patch.importTrainNumber = importTrainNumber;
if (exportTrainNumber) patch.exportTrainNumber = exportTrainNumber;
if (importTrainNumber || exportTrainNumber) {
const nextImport = importTrainNumber ?? train.importTrainNumber ?? '';
const nextExport = exportTrainNumber ?? train.exportTrainNumber ?? '';
const numberClash: { code: string }[] = await manager.query(
`SELECT code FROM freight.trains
WHERE deleted_at IS NULL
AND id != $3
AND (import_train_number IN ($1, $2)
OR export_train_number IN ($1, $2)
OR train_number IN ($1, $2))
LIMIT 1`,
[nextImport, nextExport, train.id],
);
if (numberClash.length) {
throw new ConflictException(
`Train number ${nextImport}/${nextExport} is already used by train ${numberClash[0].code}`,
);
}
}
if (Object.keys(patch).length) {
await manager.getRepository(Train).update(train.id, patch);
}
});
return this.getComposition(id);
}
/**
* Relocate the train to another yard. The consist moves as one unit: every
* coupled locomotive and wagon follows to the new yard (so their current
* yards always match the train's), and each wagon gets a movement-ledger row.
* Blocked while the train is out on a dispatched run.
*/
async setYard(id: string, currentYardId: string) {
await this.dataSource.transaction(async (manager) => {
const train = await this.getEditableTrain(manager, id);
if (train.currentYardId === currentYardId) return;
const yard = await manager.getRepository(Yard).findOne({ where: { id: currentYardId } });
if (!yard) throw new NotFoundException(`Yard ${currentYardId} not found`);
await manager.getRepository(Train).update(train.id, { currentYardId: yard.id });
const links = await manager
.getRepository(TrainLocomotive)
.find({ where: { trainId: train.id } });
if (links.length) {
await manager
.getRepository(Locomotive)
.update(
{ id: In(links.map((link) => link.locomotiveId)) },
{ currentYardId: yard.id },
);
}
const wagons = await manager.getRepository(Wagon).find({ where: { trainId: train.id } });
const now = new Date();
for (const wagon of wagons) {
if (wagon.currentYardId === yard.id) continue;
await manager.getRepository(Wagon).update(wagon.id, { currentYardId: yard.id });
// Ledger row keeps the wagon's yard history auditable (mirrors the
// manual-relocation path in the wagons service).
await manager.getRepository(WagonMovement).save(
manager.getRepository(WagonMovement).create({
wagonId: wagon.id,
fromYardId: wagon.currentYardId ?? null,
toYardId: yard.id,
kind: WagonMovementKind.Manual,
occurredAt: now,
}),
);
}
});
return this.getComposition(id);
}
/** Append AVAILABLE wagons from the train's own yard to the consist. */
async assignWagons(id: string, dto: AssignTrainWagonsDto) {
await this.dataSource.transaction(async (manager) => {
const train = await this.getEditableTrain(manager, id);
const currentCount = await manager
.getRepository(Wagon)
.count({ where: { trainId: train.id } });
await this.attachWagons(manager, train, dto.wagonIds, currentCount);
});
return this.getComposition(id);
}
/** Detach one wagon and close the sequence gap it leaves. */
async removeWagon(id: string, wagonId: string) {
await this.dataSource.transaction(async (manager) => {
const train = await this.getEditableTrain(manager, id);
const wagon = await manager.getRepository(Wagon).findOne({ where: { id: wagonId } });
if (!wagon || wagon.trainId !== train.id) {
throw new NotFoundException(`Wagon ${wagonId} is not part of this train`);
}
if (await this.isWagonPinnedToLiveSchedule(manager, wagon.id)) {
throw new ConflictException(
`Wagon ${wagon.wagonNumber} is pinned to an active schedule and cannot be removed`,
);
}
await manager.getRepository(Wagon).update(wagon.id, {
trainId: null,
sequenceNumber: null,
status: WagonStatus.Available,
});
await this.resequenceWagons(manager, train.id);
});
return this.getComposition(id);
}
/**
* Detach one wagon AND flag it for maintenance: it leaves the consist and
* moves to MAINTENANCE status (not AVAILABLE), so it is not re-coupled until
* it clears maintenance. The freed sequence gap is closed.
*/
async sendWagonToMaintenance(id: string, wagonId: string) {
await this.dataSource.transaction(async (manager) => {
const train = await this.getEditableTrain(manager, id);
const wagon = await manager.getRepository(Wagon).findOne({ where: { id: wagonId } });
if (!wagon || wagon.trainId !== train.id) {
throw new NotFoundException(`Wagon ${wagonId} is not part of this train`);
}
if (await this.isWagonPinnedToLiveSchedule(manager, wagon.id)) {
throw new ConflictException(
`Wagon ${wagon.wagonNumber} is pinned to an active schedule and cannot be removed`,
);
}
await manager.getRepository(Wagon).update(wagon.id, {
trainId: null,
sequenceNumber: null,
status: WagonStatus.Maintenance,
});
await this.resequenceWagons(manager, train.id);
});
return this.getComposition(id);
}
/**
* Schedule occupancy lives on TrainSetWagon slots (per-schedule snapshot),
* not on the Wagon entity — a wagon is busy when any live (DRAFT/SCHEDULED/
* DISPATCHED) schedule has it pinned to one of its slots.
*/
private async isWagonPinnedToLiveSchedule(
manager: EntityManager,
wagonId: string,
): Promise<boolean> {
const rows: { exists: boolean }[] = await manager.query(
`SELECT TRUE AS exists
FROM freight.train_set_wagons tsw
JOIN freight.train_schedules ts ON ts.train_set_id = tsw.train_set_id
WHERE tsw.physical_wagon_id = $1
AND ts.status IN ('DRAFT', 'SCHEDULED', 'DISPATCHED')
AND ts.deleted_at IS NULL
AND tsw.deleted_at IS NULL
LIMIT 1`,
[wagonId],
);
return rows.length > 0;
}
/** Persist a drag-reorder: `wagonIds` is the full consist in its new order. */
async reorderWagons(id: string, dto: ReorderTrainWagonsDto) {
await this.dataSource.transaction(async (manager) => {
const train = await this.getEditableTrain(manager, id);
const wagons = await manager
.getRepository(Wagon)
.find({ where: { trainId: train.id } });
const current = new Set(wagons.map((w) => w.id));
const incoming = new Set(dto.wagonIds);
if (current.size !== incoming.size || [...current].some((wid) => !incoming.has(wid))) {
throw new BadRequestException('Reorder must include every wagon of the train exactly once');
}
for (let i = 0; i < dto.wagonIds.length; i++) {
await manager.getRepository(Wagon).update(dto.wagonIds[i], { sequenceNumber: i + 1 });
}
});
return this.getComposition(id);
}
/** Disband the train: release wagons and locomotives, then delete it. */
async disband(id: string): Promise<void> {
await this.dataSource.transaction(async (manager) => {
const train = await manager.getRepository(Train).findOne({ where: { id } });
if (!train) throw new NotFoundException(`Train ${id} not found`);
const active: { count: string }[] = await manager.query(
`SELECT COUNT(*)::text AS count
FROM freight.train_schedules ts
JOIN freight.train_sets tset ON tset.id = ts.train_set_id
WHERE tset.train_id = $1
AND ts.deleted_at IS NULL
AND ts.status IN ('DRAFT', 'SCHEDULED', 'DISPATCHED')`,
[id],
);
if (Number(active[0]?.count ?? 0) > 0) {
throw new ConflictException(
'Train has active schedules; cancel them before disbanding the train',
);
}
await manager
.getRepository(Wagon)
.update(
{ trainId: train.id },
{ trainId: null, sequenceNumber: null, status: WagonStatus.Available },
);
await manager.getRepository(TrainLocomotive).delete({ trainId: train.id });
await manager.getRepository(Train).remove(train);
});
}
// ---------------------------------------------------------------- internals
/**
* System-assigned train code `TR-NNNNN`. Draws the next number from the
* highest existing `TR-` code and probes past any manual collision so the
* unique constraint never rejects the build.
*/
private async generateTrainCode(manager: EntityManager): Promise<string> {
const [row]: { max_seq: string | null }[] = await manager.query(
`SELECT MAX(CAST(SUBSTRING(code FROM '^TR-([0-9]+)$') AS INTEGER)) AS max_seq
FROM freight.trains
WHERE code ~ '^TR-[0-9]+$'`,
);
let seq = Number(row?.max_seq ?? 0) + 1;
for (let attempt = 0; attempt < 50; attempt += 1) {
const code = `TR-${String(seq).padStart(5, '0')}`;
const exists = await manager
.getRepository(Train)
.findOne({ where: { code }, withDeleted: true });
if (!exists) return code;
seq += 1;
}
throw new ConflictException('Could not allocate a unique train code');
}
private mapSummary(train: Train, activeSchedule: ActiveScheduleRef | null) {
const locomotives = [...(train.locomotives ?? [])]
.sort((a, b) => a.sequenceNo - b.sequenceNo)
.map((link) => link.locomotive)
.filter((loco): loco is Locomotive => Boolean(loco));
const wagons = train.wagons ?? [];
const totalTareTons = round(
wagons.reduce((sum, w) => sum + (Number(w.wagonType?.tareWeightTons) || 0), 0),
);
return {
id: train.id,
code: train.code,
trainName: train.trainName ?? null,
status: train.status,
importTrainNumber: train.importTrainNumber ?? null,
exportTrainNumber: train.exportTrainNumber ?? null,
activeSchedule,
createdAt: train.createdAt,
currentYard: train.currentYard
? { id: train.currentYard.id, code: train.currentYard.code, label: train.currentYard.label }
: null,
locomotives: locomotives.map((loco) => ({ id: loco.id, code: loco.code, name: loco.name ?? null })),
wagonCount: wagons.length,
totalTareTons,
totalLengthMeters: round(
wagons.reduce((sum, w) => sum + (Number(w.wagonType?.lengthMeters) || 0), 0),
),
maxPullWeightTons: round(train.capacityTons),
};
}
/** Load + freeze the train row for edit; block edits while it is out on a run. */
private async getEditableTrain(manager: EntityManager, id: string): Promise<Train> {
const train = await manager.getRepository(Train).findOne({
where: { id },
lock: { mode: 'pessimistic_write' },
});
if (!train) throw new NotFoundException(`Train ${id} not found`);
if (train.status === Freight.TrainStatus.InService) {
throw new ConflictException(
`Train ${train.code} is out on a dispatched run; its composition is frozen until arrival`,
);
}
return train;
}
/**
* Lock and validate the locomotives for a build/replace: each must exist, be
* serviceable, sit in the train's yard, and not ride another built train.
*/
private async validateAndLockLocomotives(
manager: EntityManager,
locomotiveIds: string[],
yard: Yard,
ownTrainId: string | null,
): Promise<Locomotive[]> {
const locomotives: Locomotive[] = [];
for (const locomotiveId of locomotiveIds) {
const locked = await manager.getRepository(Locomotive).findOne({
where: { id: locomotiveId },
lock: { mode: 'pessimistic_write' },
});
if (!locked) throw new NotFoundException(`Locomotive ${locomotiveId} not found`);
if (locked.status === 'OUT_OF_SERVICE' || locked.status === 'MAINTENANCE') {
throw new ConflictException(`Locomotive ${locked.code} is ${locked.status.toLowerCase().replace('_', ' ')}`);
}
if (locked.currentYardId !== yard.id) {
throw new BadRequestException(
`Locomotive ${locked.code} is not in yard ${yard.label ?? yard.code}; a train can only be built from locomotives in its own yard`,
);
}
locomotives.push(locked);
}
const taken = await manager.getRepository(TrainLocomotive).find({
where: { locomotiveId: In(locomotiveIds) },
relations: { train: true },
});
const conflict = taken.find((link) => link.trainId !== ownTrainId);
if (conflict) {
const loco = locomotives.find((l) => l.id === conflict.locomotiveId);
throw new ConflictException(
`Locomotive ${loco?.code ?? conflict.locomotiveId} is already coupled to train ${conflict.train?.code ?? conflict.trainId}`,
);
}
return locomotives;
}
private async replaceLocomotiveLinks(
manager: EntityManager,
trainId: string,
locomotiveIds: string[],
): Promise<void> {
await manager.getRepository(TrainLocomotive).delete({ trainId });
await manager.getRepository(TrainLocomotive).save(
locomotiveIds.map((locomotiveId, index) =>
manager.getRepository(TrainLocomotive).create({ trainId, locomotiveId, sequenceNo: index }),
),
);
}
private async attachWagons(
manager: EntityManager,
train: Train,
wagonIds: string[],
startCount: number,
): Promise<void> {
const uniqueIds = [...new Set(wagonIds)];
const wagonRepo = manager.getRepository(Wagon);
// First pass: lock + validate every wagon so the length gate below sees
// the full incoming set before any row is written.
const toAttach: Wagon[] = [];
for (const wagonId of uniqueIds) {
const wagon = await wagonRepo.findOne({
where: { id: wagonId },
lock: { mode: 'pessimistic_write' },
});
if (!wagon) throw new NotFoundException(`Wagon ${wagonId} not found`);
if (wagon.trainId === train.id) continue;
if (wagon.trainId) {
throw new ConflictException(`Wagon ${wagon.wagonNumber} is already on another train`);
}
if (wagon.status !== WagonStatus.Available) {
throw new ConflictException(`Wagon ${wagon.wagonNumber} is not available (${wagon.status})`);
}
if (wagon.currentYardId !== train.currentYardId) {
throw new BadRequestException(
`Wagon ${wagon.wagonNumber} is not in the train's yard; only wagons in the same yard can be attached`,
);
}
toAttach.push(wagon);
}
if (!toAttach.length) return;
await this.assertConsistLengthWithinLimit(manager, train, toAttach);
let sequence = startCount;
for (const wagon of toAttach) {
sequence += 1;
await wagonRepo.update(wagon.id, {
trainId: train.id,
sequenceNumber: sequence,
status: WagonStatus.Assigned,
});
}
}
/**
* The consist (already-attached wagons + the incoming ones) must fit the
* train's locomotive length limit — the weakest locomotive of the set caps
* the train, mirroring how scheduling derives capacity.
*/
private async assertConsistLengthWithinLimit(
manager: EntityManager,
train: Train,
incoming: Wagon[],
): Promise<void> {
const links = await manager.getRepository(TrainLocomotive).find({
where: { trainId: train.id },
relations: { locomotive: true },
});
const limits = minLocomotiveLimits(
links
.map((link) => link.locomotive)
.filter((loco): loco is Locomotive => Boolean(loco)),
);
const maxLengthMeters = Number(limits?.maxTrainLengthMeters ?? 0);
if (!Number.isFinite(maxLengthMeters) || maxLengthMeters <= 0) return;
const existing = await manager.getRepository(Wagon).find({
where: { trainId: train.id },
relations: { wagonType: true },
});
const currentLength = existing.reduce(
(sum, w) => sum + (Number(w.wagonType?.lengthMeters) || 0),
0,
);
const typeIds = [...new Set(incoming.map((w) => w.wagonTypeId).filter(Boolean))];
const types = typeIds.length
? await manager.getRepository(WagonType).find({ where: { id: In(typeIds) } })
: [];
const lengthByType = new Map(types.map((t) => [t.id, Number(t.lengthMeters) || 0]));
const addedLength = incoming.reduce(
(sum, w) => sum + (lengthByType.get(w.wagonTypeId) ?? 0),
0,
);
const totalLength = currentLength + addedLength;
if (totalLength > maxLengthMeters) {
throw new BadRequestException(
`Cannot attach wagons — train length would be ${round(totalLength)} m ` +
`(current ${round(currentLength)} m + ${round(addedLength)} m added), ` +
`over the locomotive limit of ${round(maxLengthMeters)} m. ` +
'Remove wagons from the consist or use locomotives with a higher length limit.',
);
}
}
/** Compact wagon sequence numbers back to 1..n after a removal. */
private async resequenceWagons(manager: EntityManager, trainId: string): Promise<void> {
const wagons = await manager.getRepository(Wagon).find({
where: { trainId },
order: { sequenceNumber: 'ASC' },
});
for (let i = 0; i < wagons.length; i++) {
if (wagons[i].sequenceNumber !== i + 1) {
await manager.getRepository(Wagon).update(wagons[i].id, { sequenceNumber: i + 1 });
}
}
}
}