Added a shuffle method based on the current battle seed. Standardized other RNG.

src/battle-scene.ts

@@ -1049,6 +1049,23 @@ export default class BattleScene extends SceneBase {
     return this.currentBattle?.randSeedInt(this, range, min);
   }
 
+  /**
+   * Shuffles an array based on the current battle's seed.
+   * @param {array} items a list of items
+   * @returns a new randomly shuffled array
+   */
+  randBattleSeedShuffle(items: any[]): any[] {
+    if (items.length <= 1) {
+      return items;
+    }
+    const newArray = items.slice(0);
+    for (let i = items.length - 1; i > 0; i--) {
+      const j = this.currentBattle?.randSeedInt(this, i);
+      [ newArray[i], newArray[j] ] = [ newArray[j], newArray[i] ];
+    }
+    return newArray;
+  }
+
   reset(clearScene: boolean = false, clearData: boolean = false, reloadI18n: boolean = false): void {
     if (clearData) {
       this.gameData = new GameData(this);

src/data/mystery-encounters/encounters/absolute-avarice-encounter.ts

@@ -318,7 +318,7 @@ export const AbsoluteAvariceEncounter: MysteryEncounter =
             if (returnedBerryCount > 0) {
               for (let i = 0; i < returnedBerryCount; i++) {
                 // Shuffle remaining berry types and pop
-                Phaser.Math.RND.shuffle(berryTypesAsArray);
+                pokemon.randSeedShuffle(berryTypesAsArray);
                 const randBerryType = berryTypesAsArray.pop();
 
                 const berryModType = generateModifierType(scene, modifierTypes.BERRY, [ randBerryType ]) as BerryModifierType;

src/data/mystery-encounters/utils/encounter-pokemon-utils.ts

@@ -1,6 +1,6 @@
 import BattleScene from "#app/battle-scene";
 import i18next from "i18next";
-import { isNullOrUndefined, randSeedInt } from "#app/utils";
+import { isNullOrUndefined, randSeedInt, randSeedShuffle } from "#app/utils";
 import { PokemonHeldItemModifier } from "#app/modifier/modifier";
 import Pokemon, { EnemyPokemon, PlayerPokemon } from "#app/field/pokemon";
 import { doPokeballBounceAnim, getPokeballAtlasKey, getPokeballCatchMultiplier, getPokeballTintColor } from "#app/data/pokeball";
@@ -241,7 +241,7 @@ export function getRandomSpeciesByStarterTier(starterTiers: number | [number, nu
 
   if (tryFilterStarterTiers.length > 0) {
     const index = randSeedInt(tryFilterStarterTiers.length);
-    return Phaser.Math.RND.shuffle(tryFilterStarterTiers)[index][0].speciesId;
+    return randSeedShuffle(tryFilterStarterTiers)[index][0].speciesId;
   }
 
   return Species.BULBASAUR;

src/field/pokemon.ts

@@ -4044,6 +4044,15 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     return this.randSeedInt((max - min) + 1, min);
   }
 
+  /**
+   * Shuffles an array using the current battle's seed, or the global seed if `this.scene.currentBattle` is falsy.
+   * @param {array} items an array of items
+   * @returns {array} a new shuffled array of items
+   */
+  randSeedShuffle(items: any[]): any[] {
+    return this.scene.currentBattle ? this.scene.randBattleSeedShuffle(items) : Utils.randSeedShuffle(items);
+  }
+
   /**
    * Causes a Pokemon to leave the field (such as in preparation for a switch out/escape).
    * @param clearEffects Indicates if effects should be cleared (true) or passed