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

import { beforeAll, describe, expect, it } from "vitest";
import { simulate, type Milestones, type SimulationResult } from "../balance/simulate";
import { content } from "@deadhead/content";
import { fuelPriceAt, MS_PER_HOUR, tripFuel } from "../src/index";

/**
 * Balance targets (plan Step 12.1 as amended by CR-001 to CR-013), checked on
 * the median of several worlds: one world's job luck moves a milestone by tens
 * of minutes. The invariants must hold in every world.
 */
const SEEDS = [12345, 777, 4242, 99, 2026, 31337, 8];
const RUN = { durationMs: 8 * MS_PER_HOUR };

let lighterFirst: SimulationResult[];
let freighterFirst: SimulationResult[];
beforeAll(() => {
  lighterFirst = SEEDS.map((worldSeed) => simulate({ ...RUN, worldSeed, policy: "lighter-first" }));
  freighterFirst = SEEDS.map((worldSeed) =>
    simulate({ ...RUN, worldSeed, policy: "freighter-first" }),
  );
});

/** Median real minutes to a milestone; never reached counts as infinitely late. */
function median(results: SimulationResult[], milestone: keyof Milestones): number {
  const sorted = results
    .map((r) => r.milestones[milestone] ?? Number.POSITIVE_INFINITY)
    .sort((a, b) => a - b);
  return sorted[Math.floor(sorted.length / 2)]!;
}

describe("balance simulation (Step 12.1)", () => {
  it("gives identical output for the same seed", () => {
    const a = simulate({ ...RUN, worldSeed: 4242, policy: "lighter-first" });
    const b = simulate({ ...RUN, worldSeed: 4242, policy: "lighter-first" });
    expect(b).toEqual(a);
  });

  it("accepts the deal in under 10 real minutes", () => {
    expect(median(lighterFirst, "dealAccepted")).toBeLessThan(10);
  });

  it("buys the first Market ship in 30–95 minutes (CR-013, widened for CR-016 and CR-018)", () => {
    const minutes = median(lighterFirst, "firstMarketPurchase");
    // Cheaper fuel and full deal tanks let the player buy sooner (user decision, CR-018).
    expect(minutes).toBeGreaterThanOrEqual(30);
    expect(minutes).toBeLessThanOrEqual(95);
  });

  it("discovers a new location in under 90 minutes", () => {
    expect(median(lighterFirst, "firstDiscovery")).toBeLessThan(90);
  });

  it("pays off the loan in under 4 hours of active play (CR-013)", () => {
    expect(median(lighterFirst, "loanPaidOff")).toBeLessThan(240);
  });

  it("reaches four ships Lighter-first and Freighter-first within 25 % of each other", () => {
    const a = median(lighterFirst, "ownFourShips");
    const b = median(freighterFirst, "ownFourShips");
    expect(Number.isFinite(a) && Number.isFinite(b)).toBe(true);
    expect(Math.max(a, b)).toBeLessThanOrEqual(1.25 * Math.min(a, b));
  });

  it("never soft-locks, strands an idle ship or flies a resting pilot, in any world", () => {
    for (const result of [...lighterFirst, ...freighterFirst]) {
      expect(result.violations, `${result.policy}`).toEqual([]);
    }
  });

  it("never needs emergency fuel with positive credits (CR-015, Step 15.9; Manual since CR-018)", () => {
    for (const result of [...lighterFirst, ...freighterFirst]) {
      const stuck = result.violations.filter((v) => v.rule === "needs-emergency-fuel");
      expect(stuck, `${result.policy}`).toEqual([]);
    }
  });

  it("never shows the player a job its fleet can't complete, in any world (CR-019)", () => {
    for (const result of [...lighterFirst, ...freighterFirst]) {
      expect(result.jobsShown).toBeGreaterThan(0);
      expect(result.uncompletableShown).toBe(0);
    }
  });

  it("has the veteran fly at least one contract in the first session (CR-010)", () => {
    for (const result of lighterFirst)
      expect(result.veteranContractsFirstSession).toBeGreaterThan(0);
  });

  it("leaves fuel for at least three Courier runs from Earth after the deal (Step 2.5, measured)", () => {
    // Step 12.2: the tutorial share and starting credits as actually earned. Since
    // CR-015 the deal Courier's tank counts (full since CR-018), with credits to buy more at Earth.
    const courier = content.shipModel("courier")!;
    const [earth, moon] = [content.location("earth")!, content.location("moon")!];
    const runFu = tripFuel(courier, earth, moon, content.config);
    const inTank = courier.tankCapacityFu;
    const earthPrice = fuelPriceAt(earth, content.config);
    for (const result of lighterFirst) {
      expect(result.tutorialRuns).toBe(content.config.tutorialRunsBeforeDeal);
      expect(result.tutorialShareEarned).toBeGreaterThan(0);
      expect(result.creditsAtDeal).toBe(
        content.config.startingCredits + result.tutorialShareEarned,
      );
      expect(inTank + result.creditsAtDeal! / earthPrice).toBeGreaterThanOrEqual(3 * runFu);
    }
  });

  it("reports credits and pilot levels over time", () => {
    const [run] = lighterFirst;
    expect(run!.samples.length).toBeGreaterThan(5);
    expect(run!.samples[0]).toMatchObject({ minute: 0, credits: expect.any(Number) });
    expect(run!.samples.at(-1)!.pilotLevels.length).toBeGreaterThanOrEqual(2);
  });
});

describe("the away scenario (CR-021 Step 21.8)", () => {
  // Three hours of play (four ships), then eight hours either way.
  const scenario = (worldSeed: number, mode: "active" | "away") =>
    simulate({
      worldSeed,
      policy: "lighter-first",
      durationMs: 12 * MS_PER_HOUR,
      scenario: { atMinute: 180, minutes: 8 * 60, mode },
    });
  let ratios: number[];
  let awayRuns: SimulationResult[];
  beforeAll(() => {
    awayRuns = SEEDS.map((seed) => scenario(seed, "away"));
    ratios = SEEDS.map(
      (seed, i) => awayRuns[i]!.scenarioEarnings! / scenario(seed, "active").scenarioEarnings!,
    );
  });

  it("earns 40–80% of active play with the same fleet over 8 hours away", () => {
    const sorted = [...ratios].sort((a, b) => a - b);
    const median = sorted[Math.floor(sorted.length / 2)]!;
    expect(median).toBeGreaterThanOrEqual(0.4);
    expect(median).toBeLessThanOrEqual(0.8);
  });

  it("never lets a pilot buy fuel below the spending floor or get stranded", () => {
    for (const run of awayRuns) expect(run.violations).toEqual([]);
  });
});

describe("a week away (CR-024 Step 24.7, plan 12.1)", () => {
  const away = (worldSeed: number, hours: number) =>
    simulate({
      worldSeed,
      policy: "lighter-first",
      durationMs: (3 + hours) * 60 * 60_000,
      scenario: { atMinute: 180, minutes: hours * 60, mode: "away" },
    });

  it("earns no more in 7 days away than in 24 hours plus the trips in flight when the fleet went quiet", () => {
    for (const seed of SEEDS) {
      const day = away(seed, 24);
      const week = away(seed, 7 * 24);
      expect(week.payoutInFlightAtSleep, `seed ${seed}`).not.toBeNull();
      expect(week.scenarioEarnings!, `seed ${seed}`).toBeLessThanOrEqual(
        day.scenarioEarnings! + week.payoutInFlightAtSleep!,
      );
      // The pilots did work before going quiet.
      expect(day.scenarioEarnings!, `seed ${seed}`).toBeGreaterThan(0);
      expect(week.violations).toEqual([]);
    }
  });
});