chore: update tests and imports

src/core/part-factory.ts

@@ -14,12 +14,13 @@ export function createPart<TMeta = {}>(
   template: PartTemplate<TMeta>,
   id: string
 ): Part<TMeta> {
-  return {
-    regionId: '',
-    position: [],
-    ...template,
+  const part: Part<TMeta> = {
     id,
-  } as Part<TMeta>;
+    regionId: template.regionId ?? '',
+    position: template.position ?? [],
+    ...template,
+  };
+  return part;
 }
 
 export function createParts<TMeta = {}>(
@@ -67,7 +68,7 @@ export function mergePartPools<TMeta = {}>(
   ...pools: PartPool<TMeta>[]
 ): PartPool<TMeta> {
   if (pools.length === 0) {
-    return createPartPool({} as PartTemplate<TMeta>, 0, 'merged');
+    return createEmptyPartPool<TMeta>();
   }
 
   const allPartsArray = pools.flatMap(p => Object.values(p.parts));
@@ -94,3 +95,19 @@ export function mergePartPools<TMeta = {}>(
     },
   };
 }
+
+function createEmptyPartPool<TMeta>(): PartPool<TMeta> {
+  return {
+    parts: {},
+    template: {} as PartTemplate<TMeta>,
+    draw() {
+      return undefined;
+    },
+    return(_part: Part<TMeta>) {
+      // no-op for empty pool
+    },
+    remaining() {
+      return 0;
+    },
+  };
+}

src/core/part.ts

@@ -1,4 +1,5 @@
-import {RNG} from "@/utils/rng";
+import {RNG} from '@/utils/rng';
+import {Region} from '@/core/region';
 
 export type Part<TMeta = {}> = {
   id: string;
@@ -40,3 +41,20 @@ export function getPartAtPosition<TMeta>(parts: Record<string, Part<TMeta>>, reg
   const posKey = position.join(',');
   return Object.values(parts).find(p => p.regionId === regionId && p.position.join(',') === posKey);
 }
+
+/**
+ * O(1) cell occupancy check using Region.partMap
+ */
+export function isCellOccupiedByRegion(region: Region, position: number[]): boolean {
+  return position.join(',') in region.partMap;
+}
+
+/**
+ * O(1) part lookup using Region.partMap and parts Record
+ */
+export function getPartAtPositionInRegion<TMeta>(region: Region, parts: Record<string, Part<TMeta>>, position: number[]): Part<TMeta> | undefined {
+  const posKey = position.join(',');
+  const partId = region.partMap[posKey];
+  if (!partId) return undefined;
+  return parts[partId];
+}

src/index.ts

@@ -8,7 +8,7 @@ export type { IGameContext } from './core/game';
 export { createGameContext, createGameCommandRegistry } from './core/game';
 
 export type { Part } from './core/part';
-export { flip, flipTo, roll, findPartById, isCellOccupied, getPartAtPosition } from './core/part';
+export { flip, flipTo, roll, findPartById, isCellOccupied, getPartAtPosition, isCellOccupiedByRegion, getPartAtPositionInRegion } from './core/part';
 
 export type { PartTemplate, PartPool } from './core/part-factory';
 export { createPart, createParts, createPartPool, mergePartPools } from './core/part-factory';

src/samples/boop/index.ts

@@ -1,4 +1,12 @@
-import {createGameCommandRegistry, Part, MutableSignal, createRegion, createPart, isCellOccupied as isCellOccupiedUtil, getPartAtPosition} from '@/index';
+import {
+  createGameCommandRegistry,
+  Part,
+  MutableSignal,
+  createRegion,
+  createPart,
+  isCellOccupied as isCellOccupiedUtil,
+  getPartAtPosition,
+} from '@/index';
 
 const BOARD_SIZE = 6;
 const MAX_PIECES_PER_PLAYER = 8;

src/utils/mutable-signal.ts

@@ -1,4 +1,4 @@
-import {Signal, signal, SignalOptions} from "@preact/signals-core";
+import {Signal, signal, SignalOptions} from '@preact/signals-core';
 import {create} from 'mutative';
 
 export class MutableSignal<T> extends Signal<T> {