Harden battle save validation

src/game/scenes/BattleScene.ts

@@ -55,6 +55,7 @@ import {
   type CampaignSortieItemAssignments,
   type CampaignStep
 } from '../state/campaignState';
+import { normalizeBattleSaveSlot, parseBattleSaveState, type BattleSaveState } from '../state/battleSaveState';
 import { palette } from '../ui/palette';
 import { startLazyScene } from './lazyScenes';
 
@@ -1500,32 +1501,6 @@ type TargetingGuideNotice = {
   tone: number;
 };
 
-type SavedUnitState = Pick<UnitData, 'id' | 'level' | 'exp' | 'hp' | 'maxHp' | 'attack' | 'move' | 'x' | 'y'> & {
-  equipment: UnitData['equipment'];
-  direction?: UnitDirection;
-};
-
-type BattleSaveState = {
-  version: 1;
-  battleId: string;
-  campaignStep?: CampaignStep;
-  savedAt: string;
-  turnNumber: number;
-  activeFaction: ActiveFaction;
-  rosterTab: RosterTab;
-  actedUnitIds: string[];
-  attackIntents: AttackIntent[];
-  battleLog: string[];
-  units: SavedUnitState[];
-  bonds: BondState[];
-  itemStocks?: Record<string, Record<string, number>>;
-  battleBuffs?: BattleBuffState[];
-  battleStatuses?: BattleStatusState[];
-  battleStats?: Record<string, UnitBattleStats>;
-  enemyUsableUseKeys?: string[];
-  triggeredBattleEvents?: string[];
-};
-
 const maxEquipmentLevel = 9;
 const maxCharacterLevel = 99;
 let battleScenario = defaultBattleScenario;
@@ -11362,30 +11337,19 @@ export class BattleScene extends Phaser.Scene {
   }
 
   private battleSaveStorageKeyForSlot(slot: number) {
-    return `${battleSaveStorageKey}:slot-${Phaser.Math.Clamp(Math.floor(slot), 1, campaignSaveSlotCount)}`;
+    return `${battleSaveStorageKey}:slot-${normalizeBattleSaveSlot(slot, campaignSaveSlotCount)}`;
   }
 
   private readBattleSaveState(slot: number) {
-    const normalizedSlot = Phaser.Math.Clamp(Math.floor(slot), 1, campaignSaveSlotCount);
+    const normalizedSlot = normalizeBattleSaveSlot(slot, campaignSaveSlotCount);
     const raw =
       window.localStorage.getItem(this.battleSaveStorageKeyForSlot(normalizedSlot)) ??
       (normalizedSlot === 1 ? window.localStorage.getItem(battleSaveStorageKey) ?? window.localStorage.getItem(legacyBattleSaveStorageKey) : undefined);
-    if (!raw) {
-      return undefined;
-    }
-
-    try {
-      const state = JSON.parse(raw) as BattleSaveState;
-      if (!state || state.version !== 1 || !Array.isArray(state.units)) {
-        return undefined;
-      }
-      if (state.battleId && state.battleId !== battleScenario.id) {
-        return undefined;
-      }
-      return state;
-    } catch {
-      return undefined;
-    }
+    return parseBattleSaveState(raw, {
+      expectedBattleId: battleScenario.id,
+      mapWidth: battleMap.width,
+      mapHeight: battleMap.height
+    });
   }
 
   private saveBattleState(slot = 1) {