Pause on landing + auto-unpause on dispatch (ISS-041)

Replace the ISS-011 auto-slow with pause-on-landing: when the last plane
in flight lands, tickOnce sets sim_state.paused=true WITHOUT touching
timeScale (speed preserved). flyPlane() now clears paused before
persisting so starting a flight resumes a paused sim — inside runAction(),
tick + unpause + dispatch are atomic under the sim lock.

Tests: engine.test.ts auto-slow block rewritten for pause semantics; new
flyPlane test asserts dispatch clears paused with speed untouched. E2E:
auto-slow.spec.ts renamed to pause-on-landing.spec.ts asserting the new
behavior (paused=true AND timeScale still 1000 after landing; /fly clears
paused). Cross-cutting fix: every per-spec setScale helper now POSTs
{timeScale, paused:false} — a scale-only fast-forward after a landing would
otherwise leave the clock frozen. Deliberate mid-test pauses untouched.

lib/game/actions.test.ts

@@ -167,6 +167,18 @@ describe('flyPlane', () => {
     expect(plane.fuel).toBe(PLANE_TYPES.atr72.maxFuel);
   });
 
+  it('clears paused on dispatch (ISS-041) — speed is left untouched', async () => {
+    const inst = await freshDb('fly-unpause.db');
+    // The last landing pauses the sim at whatever scale was in use.
+    await inst.db.update(schema.simState).set({ paused: true, timeScale: 250 });
+
+    await flyPlane(inst, 'plane-starter', 'LEMD');
+
+    const sim = (await inst.db.select().from(schema.simState))[0];
+    expect(sim.paused).toBe(false); // dispatch auto-resumes…
+    expect(sim.timeScale).toBe(250); // …with the stored speed preserved
+  });
+
   it('rejects a flying plane with 409', async () => {
     const inst = await freshDb('fly-flying.db');
     await inst.db.update(schema.planes)

lib/game/actions.ts

@@ -125,6 +125,9 @@ export async function flyPlane(inst: GameDb, planeId: string, destIcao: string):
       lon: origin.lon,
     })
     .where(eq(schema.planes.id, planeId));
+  // ISS-041: starting a flight resumes a paused sim (the last landing pauses it). Runs inside
+  // runAction(), so tick + unpause + dispatch are atomic under the sim lock.
+  await inst.db.update(schema.simState).set({ paused: false });
   await persist(inst);
 }
 

lib/sim/engine.test.ts

@@ -237,7 +237,7 @@ describe('deliverPackages (v0.12.0 arrival delivery)', () => {
   });
 });
 
-describe('auto-slow to 1× when the last plane lands (ISS-011)', () => {
+describe('pause on landing when the last plane lands (ISS-041)', () => {
   const FROM = 'EDDF';
   const TO = 'LEMD';
 
@@ -259,19 +259,20 @@ describe('auto-slow to 1× when the last plane lands (ISS-011)', () => {
     return { inst, from, km, type };
   }
 
-  it('last plane lands → stored timeScale becomes 1', async () => {
-    const { inst } = await setupLanding('autoslow-last.db', 1000);
+  it('last plane lands → sim pauses and stored timeScale is UNCHANGED', async () => {
+    const { inst } = await setupLanding('pause-last.db', 1000);
     vi.setSystemTime(T0 + 2_000); // one full clamped tick at scale 1000 → clock T0+2e6 ≥ arrival (T0)
 
     const sim = await tickOnce(inst);
 
-    expect(sim.timeScale).toBe(1); // persisted on the sim_state row…
-    expect((await inst.db.select().from(schema.simState))[0].timeScale).toBe(1); // …and visible to the next snapshot
+    expect(sim.paused).toBe(true); // persisted on the sim_state row…
+    expect((await inst.db.select().from(schema.simState))[0].paused).toBe(true); // …and visible to the next snapshot
+    expect(sim.timeScale).toBe(1000); // speed preserved — no auto-slow anymore (ISS-041)
     expect((await inst.db.select().from(schema.planes))[0].status).toBe('available'); // landing itself unchanged
   });
 
-  it('a landing while another plane is still flying → no change', async () => {
-    const { inst, from, type } = await setupLanding('autoslow-other.db', 1000);
+  it('a landing while another plane is still flying → no pause', async () => {
+    const { inst, from, type } = await setupLanding('pause-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,
@@ -281,32 +282,35 @@ describe('auto-slow to 1× when the last plane lands (ISS-011)', () => {
     vi.setSystemTime(T0 + 2_000);
     const sim = await tickOnce(inst);
 
-    expect(sim.timeScale).toBe(1000); // p-b still in flight — no auto-slow
+    expect(sim.paused).toBe(false); // p-b still in flight — no pause (nothing would auto-unpause it)
+    expect(sim.timeScale).toBe(1000);
     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
   });
 
-  it('already at 1× → stays 1', async () => {
-    const { inst } = await setupLanding('autoslow-one.db', 1);
+  it('last plane lands at scale 1 → pauses anyway, scale untouched', async () => {
+    const { inst } = await setupLanding('pause-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(true);
     expect(sim.timeScale).toBe(1);
     expect((await inst.db.select().from(schema.planes))[0].status).toBe('available');
   });
 
   it('paused sim with all planes landed → no change', async () => {
-    const inst = await freshDb('autoslow-paused.db');
+    const inst = await freshDb('pause-paused.db');
     // The fleet is fully grounded (the seeded starter) — a paused tick must not touch the
-    // scale even though "no plane in flight" holds: the trigger requires a landing this tick.
+    // controls even though "no plane in flight" holds: the trigger requires a landing this tick.
     await inst.db.update(schema.simState).set({ timeScale: 1000, paused: true });
 
     vi.setSystemTime(T0 + 5_000);
     const sim = await tickOnce(inst);
 
-    expect(sim.timeScale).toBe(1000); // no landing processed while paused → trigger never fires
+    expect(sim.paused).toBe(true); // no landing processed while paused → trigger never fires
+    expect(sim.timeScale).toBe(1000);
     expect((await inst.db.select().from(schema.planes))[0].status).toBe('available');
   });
 });

lib/sim/engine.ts

@@ -74,8 +74,8 @@ export async function tickOnce(inst: GameDb): Promise<schema.SimStateRow> {
   let landedThisTick = 0;
   if (advanceMs > 0) {
     await expirePackages(inst, clockMs);
-    // ISS-011: remember the landings so the tick can auto-slow to 1× when this was
-    // the last plane in flight.
+    // ISS-041: remember the landings so the tick can pause when this was the last
+    // plane in flight.
     landedThisTick = await deliverPackages(inst, clockMs);
     await spawnOpenPackages(inst, clockMs);
     // AFTER delivery on purpose: a plane that just landed gets work spawned
@@ -83,17 +83,18 @@ export async function tickOnce(inst: GameDb): Promise<schema.SimStateRow> {
     await spawnCoveragePackages(inst, clockMs);
   }
 
-  const sets: Partial<Pick<schema.SimStateRow, 'clockMs' | 'lastRealTickMs' | 'timeScale'>> = {
+  const sets: Partial<Pick<schema.SimStateRow, 'clockMs' | 'lastRealTickMs' | 'timeScale' | 'paused'>> = {
     clockMs,
     lastRealTickMs: nowMs,
   };
-  // Auto-slow (ISS-011): when ≥1 plane landed this tick and NO plane remains in flight,
-  // drop the stored timeScale to 1× — persisted here so the UI slider reflects it on the
-  // next snapshot. Arrival-triggered by design: a grounded fleet at high scale is left
-  // alone (the player speeds up manually again; there is no auto-restore).
-  if (landedThisTick > 0 && !sim.paused) {
+  // Pause on landing (ISS-041): when ≥1 plane landed this tick and NO plane remains in flight,
+  // pause the sim WITHOUT touching timeScale — speed is preserved for the next dispatch.
+  // Arrival-triggered by design: a grounded fleet at high scale is left alone (there is no
+  // auto-resume except starting a flight; see flyPlane). A paused tick never processes landings
+  // (advanceMs === 0), so the trigger can only fire on an advancing tick.
+  if (landedThisTick > 0) {
     const flying = await inst.db.select().from(schema.planes).where(eq(schema.planes.status, 'flying'));
-    if (flying.length === 0) sets.timeScale = MIN_TIME_SCALE;
+    if (flying.length === 0) sets.paused = true;
   }
 
   // Persist lastRealTickMs even when nothing advanced — it is the tick anchor.