deadhead-space-freight-tycoon/packages/sim/test/tank.test.ts

import { content } from "@deadhead/content";
import { describe, expect, it } from "vitest";
import {
  affordableRefuel,
  createDispatchRecord,
  fuelPriceAt,
  legFuel,
  legFuelCost,
  pilotShare,
  refuel,
  resolveDispatch,
  routeDistance,
  type Contract,
  type PilotState,
  type ResolveInput,
  type ShipState,
} from "../src/index";

const { config } = content;
const courier = content.shipModel("courier")!;
const [earth, moon] = [content.location("earth")!, content.location("moon")!];
const now = Date.parse("2100-01-01T00:30:00Z");
const MOON_PRICE = fuelPriceAt(moon, config);

const contract: Contract = {
  id: "c1",
  originId: "earth",
  destinationId: "moon",
  cargoTypeId: "standard",
  goodId: "consumer-goods",
  shipper: "Pacific Orbital Logistics",
  priority: false,
  deliveryWindowGameHours: null,
  tier: 0,
  massTonnes: 10,
  payout: 2000,
  requiredSkill: null,
  requiredLongHaulLevel: 0,
  offeredAt: Date.parse("2100-01-01T00:00:00Z"),
  expiresAt: Date.parse("2100-01-01T01:00:00Z"),
  firstContact: false,
};
const pilot: PilotState = {
  id: "p1",
  isAvatar: false,
  assignedShipId: "s1",
  inFlight: false,
  skills: {},
  restEndsAt: null,
};
/** A Courier at Earth with a full tank bought at Earth's price. */
const ship: ShipState = {
  id: "s1",
  modelId: "courier",
  locationId: "earth",
  inFlight: false,
  tank: { fuelFu: courier.tankCapacityFu, avgPrice: fuelPriceAt(earth, config) },
};
const record = createDispatchRecord(
  { id: "d1", ship, pilot, contract, tutorial: false, now, worldSeed: 7 },
  content,
);
/** The tank on landing: what was left after the leg's fuel came out at departure. */
const landedTank = { ...ship.tank!, fuelFu: ship.tank!.fuelFu - record.fuelBurnedFu };

function landing(policy: "auto" | "manual", credits: number): ResolveInput {
  return {
    record,
    pilotIsAvatar: false,
    discoveredIds: new Set(["earth", "moon"]),
    loanBalance: 0,
    pilotDutyHours: 0,
    pilotSkills: {},
    now: record.arrivalAt,
    fuel: { tank: landedTank, capacityFu: courier.tankCapacityFu, refuelPolicy: policy, credits },
  };
}
function resolve(input: ResolveInput) {
  const result = resolveDispatch(input, content);
  if (result.status !== "resolved") throw new Error("expected a resolution");
  return result.resolution;
}

describe("fuel tanks (Step 15.4)", () => {
  it("burns less from the Moon: the leg is shortened by 1.3 before the pay curve (0.5.95)", () => {
    const d = routeDistance(earth, moon);
    // The CR's ÷ 1.3, applied before the economic-distance curve (user decision).
    expect(legFuel(courier, moon, d, config)).toBeCloseTo(legFuel(courier, earth, d / 1.3, config));
    expect(legFuel(courier, moon, d, config)).toBeCloseTo(
      legFuel(courier, earth, d, config) / 1.3 ** config.economicDistance.exponent,
    );
  });

  it("averages the price of what is in the tank", () => {
    const filled = refuel({ fuelFu: 50, avgPrice: 2 }, 200, 50, 1);
    expect(filled.tank).toEqual({ fuelFu: 100, avgPrice: 1.5 });
    expect(filled.boughtFu).toBe(50);
    expect(filled.cost).toBe(50);
  });

  it("never fills past capacity", () => {
    const filled = refuel({ fuelFu: 90, avgPrice: 2 }, 100, 50, 1);
    expect(filled.boughtFu).toBe(10);
    expect(filled.tank.fuelFu).toBe(100);
  });

  it("buys exactly what the credits cover, up to a full tank", () => {
    // Half a tank's worth of credits at 10 cr/fu.
    const half = affordableRefuel({ fuelFu: 0, avgPrice: 0 }, 100, 10, 500);
    expect(half.boughtFu).toBe(50);
    expect(half.cost).toBe(500);
    expect(affordableRefuel({ fuelFu: 0, avgPrice: 0 }, 100, 10, 5_000).boughtFu).toBe(100);
    expect(affordableRefuel({ fuelFu: 0, avgPrice: 0 }, 100, 10, 0).boughtFu).toBe(0);
  });

  it("takes the leg's fuel from the tank and costs it at the tank's average price", () => {
    const burned = legFuel(courier, earth, routeDistance(earth, moon), config);
    expect(record.fuelBurnedFu).toBeCloseTo(burned);
    expect(record.fuelCost).toBe(legFuelCost(burned, ship.tank!));
    // Filled at Earth: 1.6 × the base price, 8 cr/fu since CR-018 (decision 0.5.110).
    expect(record.fuelCost).toBe(Math.round(burned * 8));
  });

  it("pays a hired pilot from fuel burned × average price (decision 0.5.98)", () => {
    expect(resolve(landing("manual", 0)).pilotPay).toBe(
      pilotShare(contract.payout, record.fuelCost, config),
    );
  });

  it("tops up to a full tank on landing with Auto, paying the local price", () => {
    const { topUp } = resolve(landing("auto", 10_000));
    expect(topUp).not.toBeNull();
    expect(topUp!.locationId).toBe("moon");
    expect(topUp!.tank.fuelFu).toBeCloseTo(courier.tankCapacityFu);
    expect(topUp!.boughtFu).toBeCloseTo(record.fuelBurnedFu);
    expect(topUp!.price).toBe(MOON_PRICE);
    expect(topUp!.cost).toBe(Math.round(record.fuelBurnedFu * MOON_PRICE));
  });

  it("buys nothing with Manual", () => {
    expect(resolve(landing("manual", 10_000)).topUp).toBeNull();
  });

  it("buys only what the credits after this delivery cover", () => {
    const delivery = resolve(landing("manual", 0)).credits;
    // Credits that, with this delivery's pay, cover half the fuel burned.
    const halfCost = (record.fuelBurnedFu / 2) * MOON_PRICE;
    const { topUp } = resolve(landing("auto", halfCost - delivery));
    expect(topUp!.boughtFu).toBeCloseTo(record.fuelBurnedFu / 2);
    expect(topUp!.cost).toBeLessThanOrEqual(Math.floor(halfCost));
  });

  it("leaves the tutorial loaner's fuel alone", () => {
    const loaner: ShipState = {
      id: "loaner",
      modelId: "company-courier",
      locationId: "earth",
      inFlight: false,
    };
    const avatar = { ...pilot, id: "avatar", isAvatar: true, assignedShipId: null };
    const tutorialRun = createDispatchRecord(
      { id: "t1", ship: loaner, pilot: avatar, contract, tutorial: true, now, worldSeed: 7 },
      content,
    );
    expect(tutorialRun.fuelBurnedFu).toBe(0);
    expect(tutorialRun.fuelCost).toBe(0);
    expect(resolve({ ...landing("auto", 10_000), record: tutorialRun }).topUp).toBeNull();
  });
});