import { FREIGHT_PERMS } from '../../../seed/freight-permissions.registry';
import { Route } from '../../routes/entities/route.entity';
import { Yard } from '../../rule-engine/entities/yard.entity';
import { Train } from '../../trains/entities/train.entity';
import { ExportDataset } from '../export.types';

/**
 * The list endpoint (`trains.service.ts findAll`) loads NO relations, so the
 * UI shows raw FK uuids where names belong. This dataset resolves them, which
 * makes it the clearest "the export shows more than the screen" case in the set.
 */
export const trainsDataset: ExportDataset = {
  key: 'trains',
  title: 'Trains',
  description: 'Trains with route, stations, capacity and current composition',
  group: 'Fleet',
  permission: FREIGHT_PERMS.trains.view,
  base: { entity: Train, alias: 't' },

  joins: [
    { alias: 'y', entity: Yard, on: 'y.id = t.current_yard_id' },
    { alias: 'rt', entity: Route, on: 'rt.id = t.route_id' },
    { alias: 'os', entity: Yard, on: 'os.id = t.origin_station_id' },
    { alias: 'ds', entity: Yard, on: 'ds.id = t.destination_station_id' },
  ],

  groups: [
    { id: 'train', label: 'Train' },
    { id: 'route', label: 'Route & stations' },
    { id: 'capacity', label: 'Capacity' },
    { id: 'composition', label: 'Composition' },
  ],

  fields: [
    { key: 'code', label: 'Code', type: 'string', group: 'train', default: true, select: 't.code', sortExpr: 't.code' },
    { key: 'trainNumber', label: 'Train number', type: 'string', group: 'train', default: true, select: 't.train_number' },
    { key: 'trainName', label: 'Train name', type: 'string', group: 'train', default: true, select: 't.train_name' },
    { key: 'status', label: 'Status', type: 'string', group: 'train', default: true, select: 't.status', sortExpr: 't.status' },
    { key: 'importTrainNumber', label: 'Import run', type: 'string', group: 'train', select: 't.import_train_number' },
    { key: 'exportTrainNumber', label: 'Export run', type: 'string', group: 'train', select: 't.export_train_number' },
    { key: 'locomotiveNumber', label: 'Locomotive number', type: 'string', group: 'train', select: 't.locomotive_number' },
    { key: 'notes', label: 'Notes', type: 'string', group: 'train', select: 't.notes' },
    { key: 'remarks', label: 'Remarks', type: 'string', group: 'train', select: 't.remarks' },
    { key: 'createdAt', label: 'Added', type: 'date', group: 'train', select: `to_char(t.created_at, 'YYYY-MM-DD')`, sortExpr: 't.created_at' },

    { key: 'currentYard', label: 'Current yard', type: 'string', group: 'route', default: true, requires: ['y'], select: 'y.label' },
    { key: 'currentYardCode', label: 'Current yard code', type: 'string', group: 'route', requires: ['y'], select: 'y.code' },
    { key: 'routeDirection', label: 'Route direction', type: 'string', group: 'route', requires: ['rt'], select: 'rt.direction' },
    { key: 'routeStatus', label: 'Route status', type: 'string', group: 'route', requires: ['rt'], select: 'rt.status' },
    { key: 'originStation', label: 'Origin station', type: 'string', group: 'route', requires: ['os'], select: 'os.label' },
    { key: 'destinationStation', label: 'Destination station', type: 'string', group: 'route', requires: ['ds'], select: 'ds.label' },
    { key: 'departureTime', label: 'Departure time', type: 'string', group: 'route', select: 't.departure_time::text' },
    { key: 'arrivalTime', label: 'Arrival time', type: 'string', group: 'route', select: 't.arrival_time::text' },

    { key: 'capacityTons', label: 'Capacity (t)', type: 'tons', group: 'capacity', default: true, select: 't.capacity_tons::float8', sortExpr: 't.capacity_tons' },

    {
      key: 'wagonCount', label: 'Wagons attached', type: 'number', group: 'composition', default: true,
      select: `(SELECT COUNT(*)::int FROM freight.wagons w
                WHERE w.train_id = t.id AND w.deleted_at IS NULL)`,
    },
    {
      key: 'wagonNumbers', label: 'Wagon numbers', type: 'string', group: 'composition',
      select: `(SELECT string_agg(w.wagon_number, ' | ' ORDER BY w.sequence_number NULLS LAST, w.wagon_number)
                FROM freight.wagons w
                WHERE w.train_id = t.id AND w.deleted_at IS NULL)`,
    },
  ],

  filters: [
    { key: 'status', label: 'Status', type: 'text' },
    { key: 'currentYardId', label: 'Current yard', type: 'text' },
    { key: 'search', label: 'Search code, number or name', type: 'text' },
  ],

  defaultSort: { key: 'code', dir: 'ASC' },

  scope(ctx, qb) {
    const { params } = ctx;
    qb.andWhere('t.deleted_at IS NULL');
    if (params.status) qb.andWhere('t.status = :status', { status: params.status });
    if (params.currentYardId) qb.andWhere('t.current_yard_id = :currentYardId', { currentYardId: params.currentYardId });
    if (params.search) {
      qb.andWhere('(t.code ILIKE :search OR t.train_number ILIKE :search OR t.train_name ILIKE :search)', {
        search: `%${params.search as string}%`,
      });
    }
    // Trains carry no trade direction — nothing to scope. Intentional.
  },
};