feat(explore): monster formations are weighted

server/src/modules/player/player.service.ts

@@ -2,6 +2,7 @@ import { zeroResistances, zeroStats } from '@helpers/stats';
 import {
   Element,
   ILocation,
+  IMonsterFormation,
   INotificationAction,
   Rarity,
   Stat,
@@ -19,6 +20,7 @@ import {
   Injectable,
 } from '@nestjs/common';
 import { getPatchesAfterPropChanges } from '@utils/patches';
+import { pickWeighted } from '@utils/weighted';
 import { sample } from 'lodash';
 import { Logger } from 'nestjs-pino';
 
@@ -353,7 +355,7 @@ export class PlayerService {
   }
 
   async handleFindMonster(player: Player, location: ILocation): Promise<void> {
-    const randomFormationForLocation = sample(
+    const randomFormationForLocation = pickWeighted<IMonsterFormation>(
       this.contentService
         .allFormations()
         .filter((formation) => formation.location === location.name),

server/src/utils/weighted.ts

@@ -0,0 +1,6 @@
+import { IWeighted } from '@interfaces';
+import { sample } from 'lodash';
+
+export function pickWeighted<T>(weights: IWeighted[]): T {
+  return sample(weights.map((w) => new Array(w.weight).fill(w)).flat()) as T;
+}

shared/interfaces/buildingblocks.ts

@@ -26,3 +26,8 @@ export enum Stat {
   Resistance = 'resistance',
   Special = 'special',
 }
+
+export interface IWeighted {
+  weight: number;
+  itemId: string;
+}

shared/interfaces/monster.ts

@@ -1,4 +1,4 @@
-import { Element, Stat } from './buildingblocks';
+import { Element, IWeighted, Stat } from './buildingblocks';
 
 export interface ICombatMonsterAbility {
   ability: string;
@@ -31,9 +31,10 @@ export interface IMonsterGroup {
   monster: string;
 }
 
-export interface IMonsterFormation {
+export interface IMonsterFormation extends IWeighted {
   name: string;
   itemId: string;
+  weight: number;
   location: string;
   monsters: IMonsterGroup[];
 }