[Beta][P2] Fix Grip Claw (#4614)

* [Beta][P2] Fix Grip Claw

* Add test for Grip Claw

* [test] improve grip claw's test readability

* PR feedback

---------

Co-authored-by: NightKev <34855794+DayKev@users.noreply.github.com>

src/modifier/modifier.ts

@@ -3084,11 +3084,12 @@ export abstract class HeldItemTransferModifier extends PokemonHeldItemModifier {
    * Steals an item from a set of target Pokemon.
    * This prioritizes high-tier held items when selecting the item to steal.
    * @param pokemon The {@linkcode Pokemon} holding this item
+   * @param target The {@linkcode Pokemon} to steal from (optional)
    * @param _args N/A
    * @returns `true` if an item was stolen; false otherwise.
    */
-  override apply(pokemon: Pokemon, ..._args: unknown[]): boolean {
+  override apply(pokemon: Pokemon, target?: Pokemon, ..._args: unknown[]): boolean {
-    const opponents = this.getTargets(pokemon);
+    const opponents = this.getTargets(pokemon, target);
 
     if (!opponents.length) {
       return false;
@@ -3187,7 +3188,7 @@ export class TurnHeldItemTransferModifier extends HeldItemTransferModifier {
  * @see {@linkcode HeldItemTransferModifier}
  */
 export class ContactHeldItemTransferChanceModifier extends HeldItemTransferModifier {
-  private chance: number;
+  public readonly chance: number;
 
   constructor(type: ModifierType, pokemonId: number, chancePercent: number, stackCount?: number) {
     super(type, pokemonId, stackCount);

src/test/items/grip_claw.test.ts

@@ -1,16 +1,14 @@
 import { BattlerIndex } from "#app/battle";
-import { allMoves } from "#app/data/move";
+import Pokemon from "#app/field/pokemon";
-import { Abilities } from "#app/enums/abilities";
+import { ContactHeldItemTransferChanceModifier } from "#app/modifier/modifier";
-import { BerryType } from "#app/enums/berry-type";
+import { Abilities } from "#enums/abilities";
-import { Moves } from "#app/enums/moves";
+import { BerryType } from "#enums/berry-type";
-import { Species } from "#app/enums/species";
+import { Moves } from "#enums/moves";
-import { MoveEndPhase } from "#app/phases/move-end-phase";
+import { Species } from "#enums/species";
 import GameManager from "#test/utils/gameManager";
 import Phase from "phaser";
 import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
 
-// 20 seconds
-
 describe("Items - Grip Claw", () => {
   let phaserGame: Phaser.Game;
   let game: GameManager;
@@ -30,39 +28,85 @@ describe("Items - Grip Claw", () => {
 
     game.override
       .battleType("double")
-      .moveset([ Moves.POPULATION_BOMB, Moves.SPLASH ])
+      .moveset([ Moves.TACKLE, Moves.SPLASH, Moves.ATTRACT ])
       .startingHeldItems([
-        { name: "GRIP_CLAW", count: 5 }, // TODO: Find a way to mock the steal chance of grip claw
+        { name: "GRIP_CLAW", count: 1 },
-        { name: "MULTI_LENS", count: 3 },
       ])
       .enemySpecies(Species.SNORLAX)
-      .ability(Abilities.KLUTZ)
+      .enemyAbility(Abilities.UNNERVE)
+      .ability(Abilities.UNNERVE)
       .enemyMoveset(Moves.SPLASH)
       .enemyHeldItems([
         { name: "BERRY", type: BerryType.SITRUS, count: 2 },
         { name: "BERRY", type: BerryType.LUM, count: 2 },
       ])
-      .startingLevel(100)
       .enemyLevel(100);
 
-    vi.spyOn(allMoves[Moves.POPULATION_BOMB], "accuracy", "get").mockReturnValue(100);
   });
 
-  it(
+  it("should steal items on contact and only from the attack target", async () => {
-    "should only steal items from the attack target",
+    await game.classicMode.startBattle([ Species.FEEBAS, Species.MILOTIC ]);
-    async () => {
-      await game.startBattle([ Species.PANSEAR, Species.ROWLET ]);
 
-      const enemyPokemon = game.scene.getEnemyField();
+    const [ playerPokemon, ] = game.scene.getPlayerField();
 
-      const enemyHeldItemCt = enemyPokemon.map(p => p.getHeldItems.length);
+    const gripClaw = playerPokemon.getHeldItems()[0] as ContactHeldItemTransferChanceModifier;
+    vi.spyOn(gripClaw, "chance", "get").mockReturnValue(100);
 
-      game.move.select(Moves.POPULATION_BOMB, 0, BattlerIndex.ENEMY);
+    const enemyPokemon = game.scene.getEnemyField();
-      game.move.select(Moves.SPLASH, 1);
 
-      await game.phaseInterceptor.to(MoveEndPhase, false);
+    const playerHeldItemCount = getHeldItemCount(playerPokemon);
+    const enemy1HeldItemCount = getHeldItemCount(enemyPokemon[0]);
+    const enemy2HeldItemCount = getHeldItemCount(enemyPokemon[1]);
+    expect(enemy2HeldItemCount).toBeGreaterThan(0);
 
-      expect(enemyPokemon[1].getHeldItems.length).toBe(enemyHeldItemCt[1]);
+    game.move.select(Moves.TACKLE, 0, BattlerIndex.ENEMY_2);
-    }
+    game.move.select(Moves.SPLASH, 1);
-  );
+
+    await game.phaseInterceptor.to("BerryPhase", false);
+
+    const playerHeldItemCountAfter = getHeldItemCount(playerPokemon);
+    const enemy1HeldItemCountsAfter = getHeldItemCount(enemyPokemon[0]);
+    const enemy2HeldItemCountsAfter = getHeldItemCount(enemyPokemon[1]);
+
+    expect(playerHeldItemCountAfter).toBe(playerHeldItemCount + 1);
+    expect(enemy1HeldItemCountsAfter).toBe(enemy1HeldItemCount);
+    expect(enemy2HeldItemCountsAfter).toBe(enemy2HeldItemCount - 1);
+  });
+
+  it("should not steal items when using a targetted, non attack move", async () => {
+    await game.classicMode.startBattle([ Species.FEEBAS, Species.MILOTIC ]);
+
+    const [ playerPokemon, ] = game.scene.getPlayerField();
+
+    const gripClaw = playerPokemon.getHeldItems()[0] as ContactHeldItemTransferChanceModifier;
+    vi.spyOn(gripClaw, "chance", "get").mockReturnValue(100);
+
+    const enemyPokemon = game.scene.getEnemyField();
+
+    const playerHeldItemCount = getHeldItemCount(playerPokemon);
+    const enemy1HeldItemCount = getHeldItemCount(enemyPokemon[0]);
+    const enemy2HeldItemCount = getHeldItemCount(enemyPokemon[1]);
+    expect(enemy2HeldItemCount).toBeGreaterThan(0);
+
+    game.move.select(Moves.ATTRACT, 0, BattlerIndex.ENEMY_2);
+    game.move.select(Moves.SPLASH, 1);
+
+    await game.phaseInterceptor.to("BerryPhase", false);
+
+    const playerHeldItemCountAfter = getHeldItemCount(playerPokemon);
+    const enemy1HeldItemCountsAfter = getHeldItemCount(enemyPokemon[0]);
+    const enemy2HeldItemCountsAfter = getHeldItemCount(enemyPokemon[1]);
+
+    expect(playerHeldItemCountAfter).toBe(playerHeldItemCount);
+    expect(enemy1HeldItemCountsAfter).toBe(enemy1HeldItemCount);
+    expect(enemy2HeldItemCountsAfter).toBe(enemy2HeldItemCount);
+  });
 });
+
+/*
+ * Gets the total number of items a Pokemon holds
+ */
+function getHeldItemCount(pokemon: Pokemon) {
+  return pokemon.getHeldItems().reduce((currentTotal, item) => currentTotal + item.getStackCount(), 0);
+}
+