Fixed world clock: no player time controls (ISS-117)

The world always runs at WORLD_TIME_SCALE = 24 (lib/worldClock.ts). A server
background tick (instrumentation.ts -> startBackgroundTick, 1 s interval)
advances the sim with no open browser; idle-pause freezes the clock exactly
while no plane is flying or in repair. Fresh worlds start year 2000
(STARTING_CLOCK_MS in seed.ts).

- Removed: POST /api/sim + OpenAPI entry, applyTimeControls/clampTimeScale,
  lib/timeScale.ts, LeftPane pause button + scale slider machinery,
  ISS-057 slow-on-landing/resume in flyPlane.
- Snapshot simState is now { clockMs } only; client extrapolates at the fixed
  rate between polls and freezes while idle (useSimClock).
- New test-only hook POST /api/test/set-timescale behind FLIGHT_TEST_HOOKS=1
  (sibling of set-health); all e2e setScale helpers call it, afterEach restores
  the world rate. E2E pause tests replaced by idle-pause assertions; sim.spec.ts
  activates the world via set-health + /repair for advance/expiry tests.

lib/sim/engine.test.ts

@@ -10,26 +10,33 @@ import { haversineKm, initialBearingDeg } from '@/lib/geo';
 import { weatherFor } from '@/lib/weather';
 import { FUEL_DISCOUNT_PER_REP, FUEL_PRICE_PER_L, MAX_FUEL_DISCOUNT, PLANE_TYPES, REPAIR_DURATION_MS, repRate, WEAR_PER_KM } from '@/lib/game/catalog';
 import { SPECIALS } from '@/lib/game/specials';
-import { MARKET_TARGET_OPEN_PACKAGES, mulberry32 } from '@/lib/game/seed';
+import { MARKET_TARGET_OPEN_PACKAGES, mulberry32, STARTING_CLOCK_MS } from '@/lib/game/seed';
 import { arrivalTimeFor, fuelAtWeighted, requiredFuelFor, windBurnFactor } from './movement';
 import {
-  clampTimeScale,
   deliverPackages,
   expirePackages,
   finishRepairs,
   MAX_TICK_ELAPSED_MS,
-  MAX_TIME_SCALE,
-  MIN_TIME_SCALE,
   reputationGainFor,
+  shouldAdvanceTime,
   spawnCoveragePackages,
   spawnOpenPackages,
   tickOnce,
+  WORLD_TIME_SCALE,
 } from './engine';
 
 // Engine tests run against throwaway DB files (openGameDb) with fake timers so
 // Date.now() — the only wall-clock input to a tick — is fully controlled. The
-// public tickNow()/applyTimeControls() wrappers (singleton + lock) are covered
-// by app/api/sim/route.test.ts and the e2e suite.
+// public tickNow()/setTestTimeScale() wrappers (singleton + lock) are covered by the e2e suite
+// (every spec's setScale helper hits /api/test/set-timescale; sim.spec.ts pins its validation).
+
+// ISS-117: fresh DBs seed a GROUNDED starter, so any test that needs an advancing world must put
+// a plane in flight first — departureSimTime at the game-clock origin keeps its arrival hours away.
+async function makeWorldActive(inst: Awaited<ReturnType<typeof openGameDb>>) {
+  await inst.db.update(schema.planes)
+    .set({ status: 'flying', destIcao: 'LEMD', departureSimTime: STARTING_CLOCK_MS })
+    .where(eq(schema.planes.id, 'plane-starter'));
+}
 
 let dir: string;
 const T0 = 1_750_000_000_000; // seed moment / fake "now" at DB open
@@ -53,43 +60,46 @@ async function freshDb(name: string) {
 describe('tickOnce — clock advance', () => {
   it('advances the clock by elapsed real ms × timeScale', async () => {
     const inst = await freshDb('scale.db');
+    await makeWorldActive(inst); // a grounded fleet would freeze the world (ISS-117)
     vi.setSystemTime(T0 + 1_000); // one real second later
     await inst.db.update(schema.simState).set({ timeScale: 5 });
 
     const sim = await tickOnce(inst);
 
-    expect(sim.clockMs).toBe(T0 + 5_000); // 1 s × 5
+    expect(sim.clockMs).toBe(STARTING_CLOCK_MS + 5_000); // 1 s × 5
     expect(sim.lastRealTickMs).toBe(T0 + 1_000);
   });
 
-  it('freezes the clock while paused but keeps tracking real time', async () => {
-    const inst = await freshDb('pause.db');
-    await inst.db.update(schema.simState).set({ paused: true, timeScale: 60 });
+  it('freezes the clock while the fleet is fully grounded but keeps tracking real time', async () => {
+    const inst = await freshDb('idle.db'); // seeded starter is on the ground → idle (ISS-117)
 
-    vi.setSystemTime(T0 + 3_600_000); // an hour of real pause
+    vi.setSystemTime(T0 + 3_600_000); // an hour of real idleness
     let sim = await tickOnce(inst);
-    expect(sim.clockMs).toBe(T0); // frozen — no advance at all
+    expect(sim.clockMs).toBe(STARTING_CLOCK_MS); // frozen — no advance at all
     expect(sim.lastRealTickMs).toBe(T0 + 3_600_000);
 
-    // Unpause: resumes from where it stopped, with NO catch-up for the pause.
-    await inst.db.update(schema.simState).set({ paused: false });
+    // A plane takes off: resumes from where it stopped, with NO catch-up for the idle time.
+    await inst.db.update(schema.simState).set({ timeScale: 60 });
+    await makeWorldActive(inst);
     vi.setSystemTime(T0 + 3_600_500);
     sim = await tickOnce(inst);
-    expect(sim.clockMs).toBe(T0 + 500 * 60); // only the 500 ms since unpausing × 60
+    expect(sim.clockMs).toBe(STARTING_CLOCK_MS + 500 * 60); // only the 500 ms since activity × 60
   });
 
   it('clamps long absences: a 1-hour gap advances at most MAX_TICK_ELAPSED_MS × scale', async () => {
     const inst = await freshDb('clamp.db');
+    await makeWorldActive(inst);
     vi.setSystemTime(T0 + 3_600_000); // server sat idle for an hour
 
-    const sim = await tickOnce(inst); // timeScale is the seeded 1
+    const sim = await tickOnce(inst); // timeScale is the seeded WORLD_TIME_SCALE
 
-    expect(sim.clockMs).toBe(T0 + MAX_TICK_ELAPSED_MS); // exactly one clamped tick, not a fast-forward
+    expect(sim.clockMs).toBe(STARTING_CLOCK_MS + MAX_TICK_ELAPSED_MS * WORLD_TIME_SCALE); // exactly one clamped tick, not a fast-forward
     vi.setSystemTime(T0); // reset for later tests in this file
   });
 
   it('does not advance when two ticks land in the same millisecond', async () => {
     const inst = await freshDb('same-ms.db');
+    await makeWorldActive(inst);
     vi.setSystemTime(T0 + 1_000);
     const a = await tickOnce(inst);
     const b = await tickOnce(inst); // no real time passed since `a`
@@ -100,15 +110,17 @@ describe('tickOnce — clock advance', () => {
 describe('expirePackages', () => {
   it('flips open AND loaded packages past their deadline; terminal statuses never expire', async () => {
     const inst = await freshDb('expiry.db');
-    const clock = T0 + 100_000;
+    // Game-clock anchor just after the seed moment — well inside every seeded package's deadline
+    // window (DEADLINE_MIN_HOURS), so only the rows inserted below can expire.
+    const clock = STARTING_CLOCK_MS + 100_000;
 
     await inst.db.insert(schema.packages).values([
-      { id: 'p-open-past', originIcao: 'EDDF', destIcao: 'LEMD', reward: 1, cargoType: 'Mail', cargoCount: 1, deadlineSimTime: clock - 1, status: 'open', planeId: null, createdSimTime: T0 },
-      { id: 'p-open-future', originIcao: 'EDDF', destIcao: 'LEMD', reward: 1, cargoType: 'Mail', cargoCount: 1, deadlineSimTime: clock + 1, status: 'open', planeId: null, createdSimTime: T0 },
-      { id: 'p-loaded-past', originIcao: 'EDDF', destIcao: 'LEMD', reward: 1, cargoType: 'Mail', cargoCount: 1, deadlineSimTime: clock - 1, status: 'loaded', planeId: 'plane-starter', createdSimTime: T0 },
-      { id: 'p-delivered-past', originIcao: 'EDDF', destIcao: 'LEMD', reward: 1, cargoType: 'Mail', cargoCount: 1, deadlineSimTime: clock - 1, status: 'delivered', planeId: null, createdSimTime: T0 },
-      { id: 'p-abandoned-past', originIcao: 'EDDF', destIcao: 'LEMD', reward: 1, cargoType: 'Mail', cargoCount: 1, deadlineSimTime: clock - 1, status: 'abandoned', planeId: null, createdSimTime: T0 },
-      { id: 'p-ignored-past', originIcao: 'EDDF', destIcao: 'LEMD', reward: 1, cargoType: 'Mail', cargoCount: 1, deadlineSimTime: clock - 1, status: 'ignored', planeId: null, createdSimTime: T0 },
+      { id: 'p-open-past', originIcao: 'EDDF', destIcao: 'LEMD', reward: 1, cargoType: 'Mail', cargoCount: 1, deadlineSimTime: clock - 1, status: 'open', planeId: null, createdSimTime: STARTING_CLOCK_MS },
+      { id: 'p-open-future', originIcao: 'EDDF', destIcao: 'LEMD', reward: 1, cargoType: 'Mail', cargoCount: 1, deadlineSimTime: clock + 1, status: 'open', planeId: null, createdSimTime: STARTING_CLOCK_MS },
+      { id: 'p-loaded-past', originIcao: 'EDDF', destIcao: 'LEMD', reward: 1, cargoType: 'Mail', cargoCount: 1, deadlineSimTime: clock - 1, status: 'loaded', planeId: 'plane-starter', createdSimTime: STARTING_CLOCK_MS },
+      { id: 'p-delivered-past', originIcao: 'EDDF', destIcao: 'LEMD', reward: 1, cargoType: 'Mail', cargoCount: 1, deadlineSimTime: clock - 1, status: 'delivered', planeId: null, createdSimTime: STARTING_CLOCK_MS },
+      { id: 'p-abandoned-past', originIcao: 'EDDF', destIcao: 'LEMD', reward: 1, cargoType: 'Mail', cargoCount: 1, deadlineSimTime: clock - 1, status: 'abandoned', planeId: null, createdSimTime: STARTING_CLOCK_MS },
+      { id: 'p-ignored-past', originIcao: 'EDDF', destIcao: 'LEMD', reward: 1, cargoType: 'Mail', cargoCount: 1, deadlineSimTime: clock - 1, status: 'ignored', planeId: null, createdSimTime: STARTING_CLOCK_MS },
     ]);
 
     const n = await expirePackages(inst, clock);
@@ -127,9 +139,9 @@ describe('expirePackages', () => {
     const inst = await freshDb('expiry-edge.db');
     await inst.db.insert(schema.packages).values({
       id: 'p-edge', originIcao: 'EDDF', destIcao: 'LEMD', reward: 1, cargoType: 'Mail', cargoCount: 1,
-      deadlineSimTime: T0 + 50_000, status: 'open', planeId: null, createdSimTime: T0,
+      deadlineSimTime: STARTING_CLOCK_MS + 50_000, status: 'open', planeId: null, createdSimTime: STARTING_CLOCK_MS,
     });
-    expect(await expirePackages(inst, T0 + 50_000)).toBe(1); // <= is inclusive
+    expect(await expirePackages(inst, STARTING_CLOCK_MS + 50_000)).toBe(1); // <= is inclusive
   });
 });
 
@@ -516,11 +528,13 @@ describe('finishRepairs (v0.39.0, ISS-069)', () => {
 
   it('runs inside tickOnce even when nothing landed: a past gate flips the plane back', async () => {
     const inst = await freshDb('repair-tick.db');
+    // The repairing plane keeps the world advancing (ISS-117); scale pinned to 1 for clean math.
+    await inst.db.update(schema.simState).set({ timeScale: 1 });
     await inst.db.update(schema.planes)
-      .set({ status: 'repairing', repairUntilSimTime: T0 + 1_500 })
+      .set({ status: 'repairing', repairUntilSimTime: STARTING_CLOCK_MS + 1_500 })
       .where(eq(schema.planes.id, 'plane-starter'));
 
-    vi.setSystemTime(T0 + 2_000); // one clamped tick at scale 1 → clock T0+2000 ≥ gate; nothing is flying
+    vi.setSystemTime(T0 + 2_000); // one clamped tick at scale 1 → clock STARTING_CLOCK_MS+2000 ≥ gate
     await tickOnce(inst);
 
     const plane = (await inst.db.select().from(schema.planes))[0];
@@ -560,101 +574,35 @@ describe('finishRepairs (v0.39.0, ISS-069)', () => {
   });
 });
 
-describe('slow to 1× when a landing leaves any plane on the ground (ISS-057)', () => {
-  const FROM = 'EDDF';
-  const TO = 'LEMD';
+describe('idle-pause — the world freezes when nothing is happening (ISS-117)', () => {
+  it('shouldAdvanceTime: grounded/empty fleets are idle; any flying or repairing plane advances', () => {
+    expect(shouldAdvanceTime([])).toEqual({ advance: false, flying: 0, repairing: 0 });
+    expect(shouldAdvanceTime([{ status: 'available' }, { status: 'available' }])).toEqual({ advance: false, flying: 0, repairing: 0 });
+    expect(shouldAdvanceTime([{ status: 'flying' }, { status: 'available' }])).toEqual({ advance: true, flying: 1, repairing: 0 });
+    expect(shouldAdvanceTime([{ status: 'repairing' }])).toEqual({ advance: true, flying: 0, repairing: 1 });
+    expect(shouldAdvanceTime([{ status: 'flying' }, { status: 'repairing' }])).toEqual({ advance: true, flying: 1, repairing: 1 });
+  });
 
-  // Starter flying EDDF→LEMD with departureSimTime set so its arrival is EXACTLY T0 —
-  // any advancing tick past T0 finalizes it. timeScale is the value under test;
-  // lastSelectedTimeScale mirrors what a manual POST /api/sim would have stored.
-  async function setupLanding(name: string, timeScale: number) {
-    const inst = await freshDb(name);
-    const fc = await loadAirportsGeoJson();
-    const from = fc.features.find((f) => f.properties.icao === FROM)!.properties;
-    const to = fc.features.find((f) => f.properties.icao === TO)!.properties;
-    const km = haversineKm(from.lat, from.lon, to.lat, to.lon);
-    const type = PLANE_TYPES.atr72;
+  it('a fully grounded fleet freezes the clock but keeps tracking real time', async () => {
+    const inst = await freshDb('idle-pause.db'); // seeded starter is on the ground → idle
+    vi.setSystemTime(T0 + 3_600_000);
 
-    await inst.db.update(schema.simState).set({ timeScale, lastSelectedTimeScale: timeScale });
+    const sim = await tickOnce(inst);
+
+    expect(sim.clockMs).toBe(STARTING_CLOCK_MS); // frozen — no advance at all
+    expect(sim.lastRealTickMs).toBe(T0 + 3_600_000); // …but the real-time anchor moved on
+  });
+
+  it('a repairing plane keeps the world advancing', async () => {
+    const inst = await freshDb('idle-repair.db');
     await inst.db.update(schema.planes)
-      .set({ status: 'flying', destIcao: TO, departureSimTime: T0 - travelMs(km, type.speedKmh), fuel: type.maxFuel })
+      .set({ status: 'repairing', repairUntilSimTime: STARTING_CLOCK_MS + REPAIR_DURATION_MS })
       .where(eq(schema.planes.id, 'plane-starter'));
 
-    return { inst, from, km, type };
-  }
-
-  it('last plane lands → sim slows to 1× WITHOUT pausing; lastSelectedTimeScale is preserved', async () => {
-    const { inst } = await setupLanding('slow-last.db', 1000);
-    vi.setSystemTime(T0 + 2_000); // one full clamped tick at scale 1000 → clock T0+2e6 ≥ arrival (T0)
-
+    vi.setSystemTime(T0 + 1_000);
     const sim = await tickOnce(inst);
 
-    expect(sim.paused).toBe(false); // no pause anymore — ISS-057 replaces it with a slow-down…
-    expect((await inst.db.select().from(schema.simState))[0].paused).toBe(false); // …persisted on the row…
-    expect(sim.timeScale).toBe(1); // …slowed to the floor…
-    expect(sim.lastSelectedTimeScale).toBe(1000); // …with the last manual speed kept for resume
-    expect((await inst.db.select().from(schema.planes))[0].status).toBe('available'); // landing itself unchanged
-  });
-
-  it('a landing while another plane is still flying → slows to 1× (any plane on ground)', async () => {
-    const { inst, from, type } = await setupLanding('slow-other.db', 1000);
-    // A second plane on the same route departing at T0 — arrives far after this tick's clock.
-    await inst.db.insert(schema.planes).values({
-      id: 'p-b', model: 'atr72', status: 'flying', fuel: type.maxFuel, maxFuel: type.maxFuel,
-      locationIcao: FROM, destIcao: TO, lat: from.lat, lon: from.lon, departureSimTime: T0,
-    });
-
-    vi.setSystemTime(T0 + 2_000);
-    const sim = await tickOnce(inst);
-
-    expect(sim.paused).toBe(false);
-    expect(sim.timeScale).toBe(1); // the just-landed starter is on ground → slow (literal issue reading)
-    const byId = new Map((await inst.db.select().from(schema.planes)).map((p) => [p.id, p.status]));
-    expect(byId.get('plane-starter')).toBe('available'); // the starter did land…
-    expect(byId.get('p-b')).toBe('flying'); // …but the fleet is not idle — still slowed
-  });
-
-  it('already at 1× → stays 1 (no-op slow)', async () => {
-    const { inst } = await setupLanding('slow-one.db', 1);
-    vi.setSystemTime(T0 + 2_000); // one tick at scale 1 advances 2e3 game ms — past the T0 arrival
-
-    const sim = await tickOnce(inst);
-
-    expect(sim.paused).toBe(false);
-    expect(sim.timeScale).toBe(1);
-    expect((await inst.db.select().from(schema.planes))[0].status).toBe('available');
-  });
-
-  it('a chained plane does NOT slow the sim (nothing is grounded)', async () => {
-    const { inst } = await setupLanding('slow-chain.db', 1000); // full tank, arrival exactly T0
-    // A queued next hop with plenty of fuel → chains on landing instead of grounding.
-    await inst.db.update(schema.planes)
-      .set({ queue: JSON.stringify(['EDDV']) })
-      .where(eq(schema.planes.id, 'plane-starter'));
-
-    vi.setSystemTime(T0 + 2_000); // one full clamped tick at scale 1000 → clock T0+2e6 ≥ arrival (T0)
-    const sim = await tickOnce(inst);
-
-    expect(sim.paused).toBe(false);
-    expect(sim.timeScale).toBe(1000); // still flying after the chain, nothing grounded — no slow…
-    const plane = (await inst.db.select().from(schema.planes))[0];
-    expect(plane.status).toBe('flying'); // …the fresh select in tickOnce counts it as airborne
-    expect(plane.destIcao).toBe('EDDV');
-  });
-
-  it('manually-paused sim is untouched by ticks (no landing processed while paused)', async () => {
-    const inst = await freshDb('slow-paused.db');
-    // The fleet is fully grounded (the seeded starter) — a paused tick must not touch the
-    // controls even though "any plane on ground" holds: the trigger requires a landing this tick.
-    await inst.db.update(schema.simState).set({ timeScale: 1000, lastSelectedTimeScale: 1000, paused: true });
-
-    vi.setSystemTime(T0 + 5_000);
-    const sim = await tickOnce(inst);
-
-    expect(sim.paused).toBe(true); // no landing processed while paused → trigger never fires
-    expect(sim.timeScale).toBe(1000);
-    expect(sim.lastSelectedTimeScale).toBe(1000);
-    expect((await inst.db.select().from(schema.planes))[0].status).toBe('available');
+    expect(sim.clockMs).toBeGreaterThan(STARTING_CLOCK_MS); // the repair gate is what keeps time moving
   });
 });
 
@@ -789,7 +737,13 @@ describe('spawnCoveragePackages (v0.8.0 spawn coverage rule)', () => {
 
   it('runs inside tickOnce: a fresh DB gains an EDDF-origin package after one advancing tick', async () => {
     const inst = await freshDb('coverage-tick.db');
-    vi.setSystemTime(T0 + 1_000); // one real second → advanceMs > 0 at scale 1
+    // A second, airborne plane keeps the world advancing (ISS-117) while the seeded starter stays
+    // grounded — which is what coverage spawns for. Arrival is hours out, so it never lands here.
+    await inst.db.insert(schema.planes).values({
+      id: 'p-air', model: 'atr72', status: 'flying', fuel: 6300, maxFuel: 6300,
+      locationIcao: 'EDDF', destIcao: 'LEMD', lat: 50.03, lon: 8.57, departureSimTime: STARTING_CLOCK_MS,
+    });
+    vi.setSystemTime(T0 + 1_000); // one real second → advanceMs > 0 at the seeded scale
 
     await tickOnce(inst);
 
@@ -800,32 +754,6 @@ describe('spawnCoveragePackages (v0.8.0 spawn coverage rule)', () => {
   });
 });
 
-describe('clampTimeScale — v0.14.0 ladder bounds [1, 1000]', () => {
-  it('clamps below-minimum values to MIN_TIME_SCALE', () => {
-    expect(clampTimeScale(0)).toBe(MIN_TIME_SCALE);
-    expect(clampTimeScale(-5)).toBe(MIN_TIME_SCALE);
-    expect(clampTimeScale(0.1)).toBe(MIN_TIME_SCALE);
-  });
-
-  it('clamps above-maximum values to MAX_TIME_SCALE', () => {
-    expect(clampTimeScale(1001)).toBe(MAX_TIME_SCALE);
-    expect(clampTimeScale(2000)).toBe(MAX_TIME_SCALE);
-    expect(clampTimeScale(Number.MAX_SAFE_INTEGER)).toBe(MAX_TIME_SCALE);
-  });
-
-  it('passes in-range values through unclamped — ladder and off-ladder alike', () => {
-    for (const s of [1, 2, 5, 10, 25, 50, 100, 250, 500, 1000]) {
-      expect(clampTimeScale(s)).toBe(s); // the full v0.14.0 slider ladder
-    }
-    expect(clampTimeScale(37)).toBe(37); // off-ladder but in range (e.g. a legacy value)
-  });
-
-  it('keeps the endpoints exact', () => {
-    expect(clampTimeScale(MIN_TIME_SCALE)).toBe(MIN_TIME_SCALE);
-    expect(clampTimeScale(MAX_TIME_SCALE)).toBe(MAX_TIME_SCALE);
-  });
-});
-
 // Local helper mirroring lib/sim/movement.ts (kept private there on purpose — the
 // engine composes arrivalTimeFor; tests just need the duration for fixtures).
 function travelMs(km: number, speedKmh: number): number {

lib/sim/engine.ts

@@ -18,20 +18,20 @@ import {
 } from '@/lib/game/seed';
 import { arrivalTimeFor, fuelAtWeighted, requiredFuelFor, windBurnFactor } from './movement';
 
-// Server-authoritative sim engine (v0.7.0) — tick-on-read: there is NO background
-// timer. Every read/action endpoint calls tickNow() first; the clock advances by
-// (real ms since last tick) × timeScale, clamped per tick so long absences never
-// fast-forward the game.
+// Server-authoritative sim engine (v0.7.0). ISS-117 (v0.52.0): the clock advances on a background
+// tick (~1 s, started at boot from instrumentation.ts) AND on every read/action — both through the
+// same locked tickOnce path. Each tick advances by (real ms since last tick) × timeScale, clamped
+// per tick so long absences never fast-forward the game; while no plane is flying or in repair the
+// clock stays frozen (idle-pause) but lastRealTickMs keeps tracking real time.
 
-// Clamp constant: max real-time gap counted by a single tick. Chosen at 2000 ms —
-// comfortably above a normal client poll interval (~1 s), so active play advances
-// ~real time × scale; small enough that one stale read after an absence moves game
-// time by at most 2 s × scale (≈ 33 min even at max scale 1000). The sim therefore
-// only meaningfully progresses while actively polled.
+// Clamp constant: max real-time gap counted by a single tick. Chosen at 2000 ms — comfortably above
+// both the client poll interval (~1 s) and the background-tick interval, so active play advances
+// ~real time × scale; small enough that one stale read after an absence moves game time by at most
+// 2 s × scale.
 export const MAX_TICK_ELAPSED_MS = 2_000;
 
-export const MIN_TIME_SCALE = 1;
-export const MAX_TIME_SCALE = 1000; // top of the slider ladder (v0.14.0)
+// ISS-117: the fixed world rate — re-exported here so server code and tests have one familiar home.
+export { WORLD_TIME_SCALE } from '@/lib/worldClock';
 
 // Reputation gain per delivered package: BASE + PER_KM × great-circle km, rounded
 // to 2 decimals (reputation is REAL). A short hop (~300 km) earns ~1.15 rep, a
@@ -43,11 +43,6 @@ export function reputationGainFor(km: number): number {
   return Math.round((REP_BASE + REP_PER_KM * km) * 100) / 100;
 }
 
-export interface SimControlsInput {
-  timeScale?: number;
-  paused?: boolean;
-}
-
 // Serialize ticks across concurrent requests (Next.js route handlers run in the
 // same process): each tick re-reads sim_state after the previous one wrote it, so
 // no advance is ever applied twice.
@@ -63,23 +58,36 @@ function withLock<T>(fn: () => Promise<T>): Promise<T> {
 
 // --- Tick core (takes a GameDb so unit tests can inject their own instance) ---
 
+// ISS-117: idle-pause decision — pure, so unit tests feed it synthetic fleets. The world clock
+// advances only while something is happening: at least one plane flying OR in repair. A fully
+// grounded fleet freezes the clock (and with it expiries/spawns) until a dispatch or repair starts.
+export function shouldAdvanceTime(planes: Array<{ status: string }>): { advance: boolean; flying: number; repairing: number } {
+  let flying = 0;
+  let repairing = 0;
+  for (const p of planes) {
+    if (p.status === 'flying') flying++;
+    else if (p.status === 'repairing') repairing++;
+  }
+  return { advance: flying > 0 || repairing > 0, flying, repairing };
+}
+
 export async function tickOnce(inst: GameDb): Promise<schema.SimStateRow> {
   const rows = await inst.db.select().from(schema.simState);
   const sim = rows[0];
   if (!sim) throw new Error('sim_state row missing');
 
   const nowMs = Date.now();
+  // ISS-117: frozen while nothing is happening (see shouldAdvanceTime). lastRealTickMs still
+  // tracks real time, so a takeoff resumes cleanly with no catch-up jump for the idle duration.
+  const planeRows = await inst.db.select().from(schema.planes);
+  const { advance } = shouldAdvanceTime(planeRows.map((p) => ({ status: p.status })));
   const elapsed = Math.max(0, nowMs - sim.lastRealTickMs);
-  // While paused the clock is frozen; lastRealTickMs still tracks real time so
-  // unpausing resumes cleanly with no catch-up jump for the pause duration.
-  const advanceMs = sim.paused ? 0 : Math.min(elapsed, MAX_TICK_ELAPSED_MS) * sim.timeScale;
+  const advanceMs = advance ? Math.min(elapsed, MAX_TICK_ELAPSED_MS) * sim.timeScale : 0;
   const clockMs = Math.round(sim.clockMs + advanceMs);
 
-  let landedThisTick = 0;
   if (advanceMs > 0) {
     await expirePackages(inst, clockMs);
-    // ISS-057: remember the landings so the tick can slow down when a plane is left on ground.
-    landedThisTick = await deliverPackages(inst, clockMs);
+    await deliverPackages(inst, clockMs);
     // v0.39.0 (ISS-069): repairs whose gate has passed flip back to 'available' — runs even when
     // nothing landed this tick; BEFORE the spawns so a just-repaired plane gets coverage work too.
     await finishRepairs(inst, clockMs);
@@ -89,25 +97,8 @@ export async function tickOnce(inst: GameDb): Promise<schema.SimStateRow> {
     await spawnCoveragePackages(inst, clockMs);
   }
 
-  const sets: Partial<Pick<schema.SimStateRow, 'clockMs' | 'lastRealTickMs' | 'timeScale'>> = {
-    clockMs,
-    lastRealTickMs: nowMs,
-  };
-  // Slow on landing (ISS-057): when ≥1 plane landed this tick and ANY plane is grounded
-  // ('available') afterwards, drop the sim to MIN_TIME_SCALE — a just-landed plane counts, so
-  // any real landing slows. A chained plane stays 'flying' via deliverPackages' auto-chain
-  // branch, so a pure-chain tick with nothing grounded does NOT slow. Pause is manual-only now;
-  // flyPlane restores lastSelectedTimeScale when the last grounded plane takes off. Arrival-
-  // triggered by design: a grounded fleet at high scale is left alone (no idle-enforcement), and
-  // a paused tick never processes landings (advanceMs === 0), so the trigger only fires on an
-  // advancing tick — a manual speed change while planes sit grounded survives until the next landing.
-  if (landedThisTick > 0) {
-    const available = await inst.db.select().from(schema.planes).where(eq(schema.planes.status, 'available'));
-    if (available.length >= 1) sets.timeScale = MIN_TIME_SCALE;
-  }
-
   // Persist lastRealTickMs even when nothing advanced — it is the tick anchor.
-  await inst.db.update(schema.simState).set(sets);
+  await inst.db.update(schema.simState).set({ clockMs, lastRealTickMs: nowMs });
   await persist(inst);
   const updated = (await inst.db.select().from(schema.simState))[0];
   if (!updated) throw new Error('sim_state row missing after tick');
@@ -174,8 +165,7 @@ export async function finishRepairs(inst: GameDb, clockMs: number): Promise<numb
 // remaining fuel and the queue kept intact for a later dispatch.
 // Idempotent — a finalized plane either leaves the 'flying' state or starts a NEW
 // leg whose own arrival is in the future, so it can never be awarded twice.
-// Returns planes landed. NOTE: runs BEFORE tickOnce's slow-down check on purpose —
-// a chained plane is already 'flying' again here, so a pure-chain landing never slows the sim.
+// Returns planes landed.
 export async function deliverPackages(inst: GameDb, clockMs: number): Promise<number> {
   const [planeRows, packageRows] = await Promise.all([
     inst.db.select().from(schema.planes),
@@ -423,6 +413,17 @@ export function tickNow(): Promise<schema.SimStateRow> {
   return withLock(async () => tickOnce(await getGameDb()));
 }
 
+// ISS-117: the world clock runs even with nobody polling — a ~1 s interval drives the same locked
+// tick path as reads/actions. Started once at server boot from instrumentation.ts (Next ≥15); the
+// guard makes double-starts harmless (dev HMR reloads).
+let backgroundTimer: ReturnType<typeof setInterval> | null = null;
+export function startBackgroundTick(intervalMs = 1_000): void {
+  if (backgroundTimer !== null) return;
+  backgroundTimer = setInterval(() => {
+    tickNow().catch((err) => console.error('flight: background tick failed', err));
+  }, intervalMs);
+}
+
 // Run a game action atomically with respect to ticks (v0.8.0): the clock is
 // advanced FIRST so validation and mutation see current game time, then fn runs —
 // all under the same promise lock as tickNow(), so no concurrent request can
@@ -436,31 +437,17 @@ export function runAction<T>(fn: (inst: GameDb) => Promise<T>): Promise<T> {
   });
 }
 
-// Tick first so the returned state reflects current time, then apply the new
-// controls. timeScale is clamped to [1, 1000]; validation of raw input happens in
-// the route handler (400 on non-number / non-boolean). ISS-057: posting a timeScale
-// ALSO records it as lastSelectedTimeScale — the resume target flyPlane restores when
-// the last grounded plane takes off. A {paused}-only post never touches it, so the
-// last manual intent wins without an extra flag.
-export function applyTimeControls(input: SimControlsInput): Promise<schema.SimStateRow> {
+// Test-hook backing (FLIGHT_TEST_HOOKS=1 only — see app/api/test/set-timescale/route.ts): set the
+// effective time scale under the same lock as ticks so a background tick can never interleave
+// between read and write. Input validation happens in the route; this trusts its number.
+export function setTestTimeScale(scale: number): Promise<schema.SimStateRow> {
   return withLock(async () => {
     const inst = await getGameDb();
     await tickOnce(inst);
-    const sets: Partial<Pick<schema.SimStateRow, 'timeScale' | 'lastSelectedTimeScale' | 'paused'>> = {};
-    if (input.timeScale !== undefined) {
-      const scale = clampTimeScale(input.timeScale);
-      sets.timeScale = scale;
-      sets.lastSelectedTimeScale = scale;
-    }
-    if (input.paused !== undefined) sets.paused = input.paused;
-    if (Object.keys(sets).length > 0) await inst.db.update(schema.simState).set(sets);
+    await inst.db.update(schema.simState).set({ timeScale: scale });
     await persist(inst);
     const updated = (await inst.db.select().from(schema.simState))[0];
     if (!updated) throw new Error('sim_state row missing');
     return updated;
   });
 }
-
-export function clampTimeScale(v: number): number {
-  return Math.min(MAX_TIME_SCALE, Math.max(MIN_TIME_SCALE, v));
-}