station-master/test/train-rules.test.ts

/**
 * §7 — the operating rules printed on each train's card.
 *
 * Nine of these were declared on `TrainRules` and read by nothing, so a Military train could be
 * worked by Porters and a Crack Limited could shunt an industry. Each is enforced at the point the
 * act happens, and a LOCAL CREW (`trainNumber: null`) is exempt from all of them — it has no card.
 */

import { describe, it } from 'node:test';
import assert from 'node:assert/strict';

import { advance } from '../src/engine/advance.ts';
import { applyIntent, areaOf, check } from '../src/engine/apply.ts';
import { ALL_TRAINS, trainProfile } from '../src/engine/content.ts';
import { createGame } from '../src/engine/setup.ts';
import type { GameConfig, GameState, GridCoord, RollingStock, TrackCard } from '../src/engine/state.ts';
import { coordKey, turnOf } from '../src/engine/state.ts';
import { trainRules } from '../src/sim/view.ts';

const config: GameConfig = {
  mode: 'solitaire',
  victory: 'highestAfterDays',
  length: 'standard',
  optionalRules: { reducedVisibility: false, sisterTrains: false, employeeRotation: false, emergencyToolbox: false },
};
const game = (seed = 5): GameState => createGame({ id: 'g', seed, config, playerNames: ['p'] });
const at = (row: number, col: number): GridCoord => ({ row, col });

const straight = (standing: RollingStock[] = []): TrackCard => ({
  geometry: { kind: 'track', geometry: 'straight' },
  baseOperationalRail: true,
  standing,
  standingWest: 0,
  facility: null,
  modifiers: [],
  enhancements: [],
});

/** A district of plain straight track west of the Office, and a train sitting on the Office square. */
function switching(
  s: GameState,
  trainNumber: number | null,
  isExtra: boolean,
  consist: RollingStock[] = [],
  westCars: RollingStock[] = [],
): string {
  const area = areaOf(s, 0);
  const office = area.officeCoord;
  // The crew stands one square west of the Office and works westward. It may NOT stand on the Office
  // itself: §A.4 forbids leaving Rolling Stock on the Office track, so every drop there is refused
  // whatever the train's own card says.
  const here = { row: office.row, col: office.col - 1 };
  area.grid.set(coordKey(here), straight());
  area.grid.set(coordKey({ row: office.row, col: office.col - 2 }), straight(westCars));
  area.grid.set(coordKey({ row: office.row, col: office.col - 3 }), straight());
  s.trays.set('t', {
    id: 't', trainNumber, trainIsExtra: isExtra, engineAt: 0, consist,
    direction: 'west', facing: 'w', position: { at: 'grid', seat: 0, coord: here }, movesUsed: 0,
  });
  s.clock.phase = 'localOps';
  s.clock.currentActor = 0;
  turnOf(s, 0).option = 'switch';
  turnOf(s, 0).movesRemaining = 6;
  return 't';
}

/** One square further west than the crew starts, i.e. the square carrying `westCars`. */
const west = (s: GameState, n = 2): GridCoord => {
  const o = areaOf(s, 0).officeCoord;
  return { row: o.row, col: o.col - n };
};

const boxcar = (loaded = false): RollingStock => ({ type: 'boxcar', loaded });
/** As `ROLLING_STOCK_SUPPLY` mints them: there is no empty caboose in the game. */
const caboose = (): RollingStock => ({ type: 'caboose', loaded: true });
const coach = (loaded = false): RollingStock => ({ type: 'coach', loaded });

// ---------------------------------------------------------------------------

describe('§7 — no switching', () => {
  it('still allows a plain move — "no switching" means no adding or dropping cars', () => {
    // Six cards print it: both expresses, the Light Engine, Campaign, Circus and Military trains.
    // A train held at the Office may still need to clear onto Secondary Track ahead of other
    // traffic, so a move that couples nothing is legal.
    const s = game();
    switching(s, 1, false, [boxcar()]);
    assert.equal(check(s, 0, { type: 'switch.move', trayId: 't', to: west(s), reverse: false }), null);
  });

  it('refuses a move that would couple a car, and refuses dropping and sorting outright', () => {
    const s = game();
    switching(s, 1, false, [boxcar()], [boxcar()]);

    assert.equal(
      check(s, 0, { type: 'switch.move', trayId: 't', to: west(s), reverse: false }),
      'PICKUP_NOT_ALLOWED',
    );
    assert.equal(check(s, 0, { type: 'switch.dropCars', trayId: 't', count: 1 }), 'NO_SWITCHING');
    assert.equal(check(s, 0, { type: 'switch.sortConsist', trayId: 't', order: [0] }), 'NO_SWITCHING');
  });

  it('leaves a local crew alone — it has no card and therefore no printed rules', () => {
    const s = game();
    switching(s, null, false, [boxcar()]);
    assert.equal(check(s, 0, { type: 'switch.move', trayId: 't', to: west(s), reverse: false }), null);
    assert.equal(check(s, 0, { type: 'switch.dropCars', trayId: 't', count: 1 }), null);
  });

  it('leaves an ordinary freight train alone', () => {
    // Train 9 Heavy Freight prints no rules at all, so nothing here may touch it.
    const s = game();
    switching(s, 9, false, [boxcar()]);
    assert.equal(check(s, 0, { type: 'switch.move', trayId: 't', to: west(s), reverse: false }), null);
  });
});

describe('§7 — what a train may couple', () => {
  it('X13 Appleseed may drop but not pick up', () => {
    // Coupling is mandatory (§A.4), so the restriction has to bite on the MOVE that would pick the
    // cars up — there is no moving over them and leaving them behind.
    const s = game();
    switching(s, 13, true, [boxcar()], [boxcar()]);
    assert.equal(
      check(s, 0, { type: 'switch.move', trayId: 't', to: west(s), reverse: false }),
      'PICKUP_NOT_ALLOWED',
    );
    // Setting out is exactly what it IS allowed to do.
    assert.equal(check(s, 0, { type: 'switch.dropCars', trayId: 't', count: 1 }), null);
  });

  it('X22 Pee-Dee may pick up empties and refuses a loaded car', () => {
    const empty = game();
    switching(empty, 22, true, [], [boxcar(false)]);
    assert.equal(check(empty, 0, { type: 'switch.move', trayId: 't', to: west(empty), reverse: false }), null);

    const loaded = game();
    switching(loaded, 22, true, [], [boxcar(true)]);
    assert.equal(
      check(loaded, 0, { type: 'switch.move', trayId: 't', to: west(loaded), reverse: false }),
      'EMPTIES_ONLY',
    );
  });

  it('X22 Pee-Dee may still couple a caboose, which is not a load (Gitea#8)', () => {
    // Every caboose in the game is minted `loaded: true` because the supply table's loaded/empty
    // split doubles as a piece count. Taken literally that left the per-diem train unable to pick
    // up ANY caboose, its own included: set it out at the end of a sweep and it was stranded there.
    const s = game();
    switching(s, 22, true, [], [caboose()]);
    assert.equal(check(s, 0, { type: 'switch.move', trayId: 't', to: west(s), reverse: false }), null);

    // The restriction itself is untouched — a loaded car alongside the caboose still refuses.
    const withLoad = game();
    switching(withLoad, 22, true, [], [caboose(), boxcar(true)]);
    assert.equal(
      check(withLoad, 0, { type: 'switch.move', trayId: 't', to: west(withLoad), reverse: false }),
      'EMPTIES_ONLY',
    );
  });
});

describe('§7 — one freight car per location (trains 3/4)', () => {
  it('spends the budget per SQUARE, not per turn', () => {
    // "May drop or pick up one freight car at every location" — so a second car on the same square
    // is refused, and the same train may still work another car one square along.
    const s = game();
    switching(s, 4, false, [boxcar(), boxcar()]);

    assert.equal(check(s, 0, { type: 'switch.dropCars', trayId: 't', count: 2 }), 'FREIGHT_WORKED_HERE');
    assert.ok(applyIntent(s, 0, { type: 'switch.dropCars', trayId: 't', count: 1 }).ok);
    assert.equal(
      check(s, 0, { type: 'switch.dropCars', trayId: 't', count: 1 }),
      'FREIGHT_WORKED_HERE',
      'a second car came off the same square',
    );

    // One square west, the budget is fresh.
    assert.ok(applyIntent(s, 0, { type: 'switch.move', trayId: 't', to: west(s), reverse: false }).ok);
    assert.equal(check(s, 0, { type: 'switch.dropCars', trayId: 't', count: 1 }), null);
  });

  it('shares one budget between dropping and picking up, as the card says "drop OR pick up"', () => {
    const s = game();
    switching(s, 4, false, [boxcar()], [boxcar()]);
    // Drop here first, then try to take the car standing one square west… which is a new square, so
    // it is allowed; the point is that the drop was charged where it happened.
    assert.ok(applyIntent(s, 0, { type: 'switch.dropCars', trayId: 't', count: 1 }).ok);
    assert.equal(check(s, 0, { type: 'switch.dropCars', trayId: 't', count: 1 }), 'CONSIST_EMPTY');
  });

  it('does not count a caboose or a coach against it — the card says FREIGHT', () => {
    const s = game();
    switching(s, 4, false, [coach(), { type: 'caboose', loaded: false }]);
    assert.equal(check(s, 0, { type: 'switch.dropCars', trayId: 't', count: 2 }), null);
  });
});

describe('§7 — the Local keeps its coach (trains 7/8)', () => {
  it('never sets the coach out while switching, but shunts its freight freely', () => {
    /**
     * "Coach must remain on station track if switching." The intended reading was "set out only at
     * the Office" — but §A.4 refuses the Office square to every drop, so "only there" and "nowhere"
     * are the same rule. What is enforced is the effect that matters: the Local may work its freight
     * car around the district and may not abandon its coach doing it.
     */
    // Consist reads nose-first with the engine at index 0, so both cars trail it and a cut comes off
    // the tail: one car is the coach, two cars is the boxcar and the coach together.
    const s = game();
    switching(s, 7, false, [boxcar(), coach()]);
    assert.equal(check(s, 0, { type: 'switch.dropCars', trayId: 't', count: 1 }), 'COACH_MUST_STAY');
    assert.equal(check(s, 0, { type: 'switch.dropCars', trayId: 't', count: 2 }), 'COACH_MUST_STAY');

    // The same train with only freight behind it shunts exactly as any other train would.
    const freight = game();
    switching(freight, 7, false, [boxcar()]);
    assert.equal(check(freight, 0, { type: 'switch.dropCars', trayId: 't', count: 1 }), null);
  });

  it('leaves an ordinary train free to set a coach out', () => {
    const s = game();
    switching(s, 9, false, [boxcar(), coach()]);
    assert.equal(check(s, 0, { type: 'switch.dropCars', trayId: 't', count: 1 }), null);
  });
});

describe('§7 — trains Porters may not work', () => {
  /** An Office holding a train, with passengers waiting and an empty coach to put them in. */
  function platform(s: GameState, trainNumber: number, isExtra: boolean, tier: 'depot' | 'terminal') {
    const area = areaOf(s, 0);
    area.tier = tier;
    const office = area.grid.get(coordKey(area.officeCoord))!;
    office.facility = {
      kind: 'passenger', subtype: 'office',
      allows: { outbound: true, inbound: true },
      outboundBox: [coach(true)], inboundBox: [],
      capacity: { outbound: 2, inbound: 2 },
      menAtWork: null,
      industryTrack: { cars: [] },
      laborers: 0, porters: 2, usedThisStage: { laborers: 0, porters: 0 },
    };
    s.trays.set('t', {
      id: 't', trainNumber, trainIsExtra: isExtra, engineAt: 0, consist: [coach(false)],
      direction: 'east', position: { at: 'grid', seat: 0, coord: area.officeCoord }, movesUsed: 0,
    });
    area.adOccupancy.push('t');
    s.clock.phase = 'loadUnload';
    s.clock.currentActor = 0;
    return area.officeCoord;
  }

  it('refuses the Military train and the Director\'s car outright', () => {
    for (const n of [19, 20]) {
      const s = game();
      const where = platform(s, n, true, 'terminal');
      assert.equal(
        check(s, 0, { type: 'porter.board', at: where }), 'NO_PASSENGER_WORK',
        `train X${n} was worked by a Porter`,
      );
    }
  });

  it('works the Crack Limited at a Terminal and nowhere else', () => {
    // "Stop at Terminals only" — it still runs into every Office and takes an A/D track, but the
    // passengers it is carrying can only be worked where it is booked to stop.
    const depot = game();
    const atDepot = platform(depot, 2, false, 'depot');
    assert.equal(check(depot, 0, { type: 'porter.board', at: atDepot }), 'NOT_A_TERMINAL');

    const terminal = game();
    const atTerminal = platform(terminal, 2, false, 'terminal');
    assert.equal(check(terminal, 0, { type: 'porter.board', at: atTerminal }), null);
  });

  it('still works an ordinary train at a Depot', () => {
    const s = game();
    const where = platform(s, 7, false, 'depot');
    assert.equal(check(s, 0, { type: 'porter.board', at: where }), null);
  });
});

describe('§7 — the Campaign Train stops once, then runs expedited', () => {
  it('makes its speech at the first Office and expedites afterwards', () => {
    // X17 prints "one turn at station (speeches) then expedite". The first arrival is an ordinary
    // stop; from then on it departs in the Stage it arrives, like any expedited train.
    const s = game();
    const ml = s.division.nodes[1];
    if (ml?.kind === 'mainline') {
      ml.card = 'plains';
      ml.transits.push({ tray: 'x17', stagesRemaining: 1, stagesTotal: 1, direction: 'east' });
    }
    s.trays.set('x17', {
      id: 'x17', trainNumber: 17, trainIsExtra: true, engineAt: 0, consist: [],
      direction: 'east', position: { at: 'mainline', index: 1 }, movesUsed: 0,
    });
    s.clock.phase = 'mainline';
    s.movedThisPhase = new Set();

    advance(s);

    const tray = s.trays.get('x17');
    assert.ok(tray, 'the Campaign Train vanished');
    assert.equal(tray!.position.at, 'grid', 'it should stop at the first Office for the speeches');
    assert.equal(tray!.speechMade, true, 'the speech was not recorded');
  });
});

describe('§7 — the catalogue and what it claims', () => {
  it('no longer tells a player a rule is unenforced', () => {
    for (const t of ALL_TRAINS) {
      const text = trainRules({ trainNumber: t.number, trainIsExtra: t.isExtra });
      assert.doesNotMatch(text, /NOT YET ENFORCED/, `${t.name} still apologises for its own card`);
    }
  });

  it('describes every rule a train actually carries', () => {
    // Train 1 carries three at once, so the tooltip has to say all three.
    const limited = trainRules({ trainNumber: 1, trainIsExtra: false });
    assert.match(limited, /NO SWITCHING/);
    assert.match(limited, /TERMINALS ONLY/);
    assert.match(limited, /EXPEDITED/);
  });

  it('has dropped copiesNextScheduled, which no train ever carried', () => {
    // A Second Section is a Maneuver card with its own intent (`newTrain.secondSection`), not a
    // property of a train card. The flag was an unreachable second description of a working mechanic.
    for (const t of ALL_TRAINS) {
      assert.equal(
        (t.rules as Record<string, unknown>).copiesNextScheduled, undefined,
        `${t.name} carries a flag that should not exist`,
      );
    }
    assert.ok(trainProfile(1, false), 'the catalogue should still load');
  });
});