fix(sim): no arrivals at closing time, robust save import

src/sim/clock.ts

@@ -18,7 +18,7 @@ export function tick(state: GameState, catalog: Catalog, deltaMinutes: number):
   for (let i = 0; i < deltaMinutes && state.minutes < CLOSE_MINUTES; i++) {
     state.minutes += 1;
     if (state.minutes === OPEN_MINUTES) events.push({ type: 'shop_opened' });
-    if (state.minutes > OPEN_MINUTES) {
+    if (state.minutes > OPEN_MINUTES && state.minutes < CLOSE_MINUTES) {
       state.customerAccumulator += (customersPerHour(state.reputation) / 60) * (0.5 + random(state));
       while (state.customerAccumulator >= 1) {
         state.customerAccumulator -= 1;

src/sim/save.ts

@@ -16,12 +16,25 @@ export function serialize(state: GameState): string {
   return JSON.stringify(state);
 }
 
+const OBJECT_FIELDS = ['date', 'inventory', 'loyalty', 'day', 'prices', 'pendingOrders'] as const;
+const NUMBER_FIELDS = ['cash', 'minutes', 'reputation', 'rngState', 'nextCustomerId', 'customerAccumulator'] as const;
+
 export function deserialize(json: string): GameState {
-  const data = JSON.parse(json);
-  if (data.saveVersion !== 1) throw new Error(`Unsupported save version: ${data.saveVersion}`);
-  if (typeof data.cash !== 'number' || !data.date || !data.inventory || !data.loyalty) {
+  let data: unknown;
+  try {
+    data = JSON.parse(json);
+  } catch {
     throw new Error('Corrupted save');
   }
+  if (typeof data !== 'object' || data === null || Array.isArray(data)) throw new Error('Corrupted save');
+  const record = data as Record<string, unknown>;
+  if (record.saveVersion !== 1) throw new Error(`Unsupported save version: ${record.saveVersion}`);
+  for (const field of OBJECT_FIELDS) {
+    if (typeof record[field] !== 'object' || record[field] === null) throw new Error('Corrupted save');
+  }
+  for (const field of NUMBER_FIELDS) {
+    if (typeof record[field] !== 'number') throw new Error('Corrupted save');
+  }
   return data as GameState;
 }
 

tests/sim/clock.test.ts

@@ -24,6 +24,26 @@ describe('clock', () => {
     expect(isOpen(s)).toBe(false);
   });
 
+  it('never brings customers on the closing tick', () => {
+    for (let seed = 1; seed <= 20; seed++) {
+      const s = createNewGame(seed);
+      s.reputation = 100;
+      const arrivalMinutes: number[] = [];
+      let opened = 0;
+      let closed = 0;
+      while (s.minutes < CLOSE_MINUTES) {
+        const events = tick(s, catalog, 1);
+        if (events.some((e) => e.type === 'customer_arrived')) arrivalMinutes.push(s.minutes);
+        opened += events.filter((e) => e.type === 'shop_opened').length;
+        closed += events.filter((e) => e.type === 'shop_closed').length;
+      }
+      expect(arrivalMinutes.length).toBeGreaterThan(0);
+      expect(arrivalMinutes).not.toContain(CLOSE_MINUTES);
+      expect(opened).toBe(1);
+      expect(closed).toBe(1);
+    }
+  });
+
   it('does nothing once closed', () => {
     const s = createNewGame(1);
     tick(s, catalog, 24 * 60);

tests/sim/save.test.ts

@@ -2,6 +2,7 @@ import { describe, it, expect } from 'vitest';
 import { deserialize, loadGame, saveGame, SaveStorage, serialize } from '../../src/sim/save';
 import { createNewGame } from '../../src/sim/state';
 import { issueCard } from '../../src/sim/loyalty';
+import { STARTING_CASH_CENTS } from '../../src/sim/economy';
 
 function memoryStorage(): SaveStorage {
   const data = new Map<string, string>();
@@ -25,6 +26,18 @@ describe('save', () => {
     expect(() => deserialize('{"saveVersion":1}')).toThrow('Corrupted save');
   });
 
+  it('rejects invalid JSON and non-object saves', () => {
+    expect(() => deserialize('{not json')).toThrow('Corrupted save');
+    expect(() => deserialize('null')).toThrow('Corrupted save');
+    expect(() => deserialize('[]')).toThrow('Corrupted save');
+    expect(() => deserialize('42')).toThrow('Corrupted save');
+  });
+
+  it('rejects saves with a missing field', () => {
+    const { day: _day, ...rest } = createNewGame(1);
+    expect(() => deserialize(JSON.stringify(rest))).toThrow('Corrupted save');
+  });
+
   it('keeps the current and monthly saves apart', () => {
     const storage = memoryStorage();
     const s = createNewGame(1);
@@ -32,7 +45,7 @@ describe('save', () => {
     s.cash = 1;
     saveGame(storage, s, { monthly: false });
     expect(loadGame(storage, 'current')!.cash).toBe(1);
-    expect(loadGame(storage, 'monthly')!.cash).not.toBe(1);
+    expect(loadGame(storage, 'monthly')!.cash).toBe(STARTING_CASH_CENTS);
   });
 
   it('returns null when nothing is saved', () => {