[Move] Implement Power Trick (#2658)

* add `PowerTrickTag`

* modify getStat() with PowerTrickTag

* implement `PowerTrickAttr`

* add unit test

* enhance docs and tag apply logic

---------

Co-authored-by: Lugiad' <adrien.grivel@hotmail.fr>
Co-authored-by: José Ricardo Fleury Oliveira <josefleury@discente.ufg.br>
Co-authored-by: Jannik Tappert <38758606+CodeTappert@users.noreply.github.com>
Co-authored-by: Enoch <enoch.jwsong@gmail.com>
Co-authored-by: Yonmaru40 <47717431+40chyan@users.noreply.github.com>
Co-authored-by: Amani H. <109637146+xsn34kzx@users.noreply.github.com>
Co-authored-by: Niccolò <123510358+NicusPulcis@users.noreply.github.com>
Co-authored-by: NightKev <34855794+DayKev@users.noreply.github.com>

src/data/battler-tags.ts

@@ -2724,6 +2724,44 @@ export class TelekinesisTag extends BattlerTag {
   }
 }
 
+/**
+ * Tag that swaps the user's base ATK stat with its base DEF stat.
+ * @extends BattlerTag
+ */
+export class PowerTrickTag extends BattlerTag {
+  constructor(sourceMove: Moves, sourceId: number) {
+    super(BattlerTagType.POWER_TRICK, BattlerTagLapseType.CUSTOM, 0, sourceMove, sourceId, true);
+  }
+
+  onAdd(pokemon: Pokemon): void {
+    this.swapStat(pokemon);
+    pokemon.scene.queueMessage(i18next.t("battlerTags:powerTrickActive", { pokemonNameWithAffix: getPokemonNameWithAffix(pokemon) }));
+  }
+
+  onRemove(pokemon: Pokemon): void {
+    this.swapStat(pokemon);
+    pokemon.scene.queueMessage(i18next.t("battlerTags:powerTrickActive", { pokemonNameWithAffix: getPokemonNameWithAffix(pokemon) }));
+  }
+
+  /**
+   * Removes the Power Trick tag and reverts any stat changes if the tag is already applied.
+   * @param {Pokemon} pokemon The {@linkcode Pokemon} that already has the Power Trick tag.
+   */
+  onOverlap(pokemon: Pokemon): void {
+    pokemon.removeTag(this.tagType);
+  }
+
+  /**
+   * Swaps the user's base ATK stat with its base DEF stat.
+   * @param {Pokemon} pokemon The {@linkcode Pokemon} whose stats will be swapped.
+   */
+  swapStat(pokemon: Pokemon): void {
+    const temp = pokemon.getStat(Stat.ATK, false);
+    pokemon.setStat(Stat.ATK, pokemon.getStat(Stat.DEF, false), false);
+    pokemon.setStat(Stat.DEF, temp, false);
+  }
+}
+
 /**
  * Retrieves a {@linkcode BattlerTag} based on the provided tag type, turn count, source move, and source ID.
  * @param sourceId - The ID of the pokemon adding the tag
@@ -2899,6 +2937,8 @@ export function getBattlerTag(tagType: BattlerTagType, turnCount: number, source
     return new SyrupBombTag(sourceId);
   case BattlerTagType.TELEKINESIS:
     return new TelekinesisTag(sourceMove);
+  case BattlerTagType.POWER_TRICK:
+    return new PowerTrickTag(sourceMove, sourceId);
   case BattlerTagType.NONE:
   default:
     return new BattlerTag(tagType, BattlerTagLapseType.CUSTOM, turnCount, sourceMove, sourceId);

src/data/move.ts

@@ -6430,6 +6430,9 @@ export class TransformAttr extends MoveEffectAttr {
       user.summonData.gender = target.getGender();
       user.summonData.fusionGender = target.getFusionGender();
 
+      // Power Trick's effect will not preserved after using Transform
+      user.removeTag(BattlerTagType.POWER_TRICK);
+
       // Copy all stats (except HP)
       for (const s of EFFECTIVE_STATS) {
         user.setStat(s, target.getStat(s, false), false);
@@ -8153,7 +8156,7 @@ export function initMoves() {
       .attr(OpponentHighHpPowerAttr, 120)
       .makesContact(),
     new SelfStatusMove(Moves.POWER_TRICK, Type.PSYCHIC, -1, 10, -1, 0, 4)
-      .unimplemented(),
+      .attr(AddBattlerTagAttr, BattlerTagType.POWER_TRICK, true),
     new StatusMove(Moves.GASTRO_ACID, Type.POISON, 100, 10, -1, 0, 4)
       .attr(SuppressAbilitiesAttr),
     new StatusMove(Moves.LUCKY_CHANT, Type.NORMAL, -1, 30, -1, 0, 4)

src/enums/battler-tag-type.ts

@@ -80,6 +80,7 @@ export enum BattlerTagType {
   DOUBLE_SHOCKED = "DOUBLE_SHOCKED",
   AUTOTOMIZED = "AUTOTOMIZED",
   MYSTERY_ENCOUNTER_POST_SUMMON = "MYSTERY_ENCOUNTER_POST_SUMMON",
+  POWER_TRICK = "POWER_TRICK",
   HEAL_BLOCK = "HEAL_BLOCK",
   TORMENT = "TORMENT",
   TAUNT = "TAUNT",

src/field/pokemon.ts

@@ -19,7 +19,7 @@ import { initMoveAnim, loadMoveAnimAssets } from "#app/data/battle-anims";
 import { Status, StatusEffect, getRandomStatus } from "#app/data/status-effect";
 import { pokemonEvolutions, pokemonPrevolutions, SpeciesFormEvolution, SpeciesEvolutionCondition, FusionSpeciesFormEvolution } from "#app/data/balance/pokemon-evolutions";
 import { reverseCompatibleTms, tmSpecies, tmPoolTiers } from "#app/data/balance/tms";
-import { BattlerTag, BattlerTagLapseType, EncoreTag, GroundedTag, HighestStatBoostTag, SubstituteTag, TypeImmuneTag, getBattlerTag, SemiInvulnerableTag, TypeBoostTag, MoveRestrictionBattlerTag, ExposedTag, DragonCheerTag, CritBoostTag, TrappedTag, TarShotTag, AutotomizedTag } from "../data/battler-tags";
+import { BattlerTag, BattlerTagLapseType, EncoreTag, GroundedTag, HighestStatBoostTag, SubstituteTag, TypeImmuneTag, getBattlerTag, SemiInvulnerableTag, TypeBoostTag, MoveRestrictionBattlerTag, ExposedTag, DragonCheerTag, CritBoostTag, TrappedTag, TarShotTag, AutotomizedTag, PowerTrickTag } from "../data/battler-tags";
 import { WeatherType } from "#app/data/weather";
 import { ArenaTagSide, NoCritTag, WeakenMoveScreenTag } from "#app/data/arena-tag";
 import { Ability, AbAttr, StatMultiplierAbAttr, BlockCritAbAttr, BonusCritAbAttr, BypassBurnDamageReductionAbAttr, FieldPriorityMoveImmunityAbAttr, IgnoreOpponentStatStagesAbAttr, MoveImmunityAbAttr, PreDefendFullHpEndureAbAttr, ReceivedMoveDamageMultiplierAbAttr, ReduceStatusEffectDurationAbAttr, StabBoostAbAttr, StatusEffectImmunityAbAttr, TypeImmunityAbAttr, WeightMultiplierAbAttr, allAbilities, applyAbAttrs, applyStatMultiplierAbAttrs, applyPreApplyBattlerTagAbAttrs, applyPreAttackAbAttrs, applyPreDefendAbAttrs, applyPreSetStatusAbAttrs, UnsuppressableAbilityAbAttr, SuppressFieldAbilitiesAbAttr, NoFusionAbilityAbAttr, MultCritAbAttr, IgnoreTypeImmunityAbAttr, DamageBoostAbAttr, IgnoreTypeStatusEffectImmunityAbAttr, ConditionalCritAbAttr, applyFieldStatMultiplierAbAttrs, FieldMultiplyStatAbAttr, AddSecondStrikeAbAttr, UserFieldStatusEffectImmunityAbAttr, UserFieldBattlerTagImmunityAbAttr, BattlerTagImmunityAbAttr, MoveTypeChangeAbAttr, FullHpResistTypeAbAttr, applyCheckTrappedAbAttrs, CheckTrappedAbAttr, PostSetStatusAbAttr, applyPostSetStatusAbAttrs } from "#app/data/ability";
@@ -3048,6 +3048,10 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
         continue;
       }
 
+      if (tag instanceof PowerTrickTag) {
+        tag.swapStat(this);
+      }
+
       this.summonData.tags.push(tag);
     }
 

src/test/moves/power_trick.test.ts

@@ -0,0 +1,113 @@
+import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
+import Phaser from "phaser";
+import GameManager from "#app/test/utils/gameManager";
+import { Moves } from "#enums/moves";
+import { Stat } from "#enums/stat";
+import { Species } from "#enums/species";
+import { TurnEndPhase } from "#app/phases/turn-end-phase";
+import { Abilities } from "#enums/abilities";
+import { BattlerTagType } from "#enums/battler-tag-type";
+
+describe("Moves - Power Trick", () => {
+  let phaserGame: Phaser.Game;
+  let game: GameManager;
+
+  beforeAll(() => {
+    phaserGame = new Phaser.Game({
+      type: Phaser.HEADLESS,
+    });
+  });
+
+  afterEach(() => {
+    game.phaseInterceptor.restoreOg();
+  });
+
+  beforeEach(() => {
+    game = new GameManager(phaserGame);
+    game.override
+      .battleType("single")
+      .enemyAbility(Abilities.BALL_FETCH)
+      .enemyMoveset(Moves.SPLASH)
+      .enemySpecies(Species.MEW)
+      .enemyLevel(200)
+      .moveset([ Moves.POWER_TRICK ])
+      .ability(Abilities.BALL_FETCH);
+  });
+
+  it("swaps the user's ATK and DEF stats", async () => {
+    await game.classicMode.startBattle([ Species.SHUCKLE ]);
+
+    const player = game.scene.getPlayerPokemon()!;
+    const baseATK = player.getStat(Stat.ATK, false);
+    const baseDEF = player.getStat(Stat.DEF, false);
+
+    game.move.select(Moves.POWER_TRICK);
+
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    expect(player.getStat(Stat.ATK, false)).toBe(baseDEF);
+    expect(player.getStat(Stat.DEF, false)).toBe(baseATK);
+    expect(player.getTag(BattlerTagType.POWER_TRICK)).toBeDefined();
+  });
+
+  it("resets initial ATK and DEF stat swap when used consecutively", async () => {
+    await game.classicMode.startBattle([ Species.SHUCKLE ]);
+
+    const player = game.scene.getPlayerPokemon()!;
+    const baseATK = player.getStat(Stat.ATK, false);
+    const baseDEF = player.getStat(Stat.DEF, false);
+
+    game.move.select(Moves.POWER_TRICK);
+
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    game.move.select(Moves.POWER_TRICK);
+
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    expect(player.getStat(Stat.ATK, false)).toBe(baseATK);
+    expect(player.getStat(Stat.DEF, false)).toBe(baseDEF);
+    expect(player.getTag(BattlerTagType.POWER_TRICK)).toBeUndefined();
+  });
+
+  it("should pass effect when using BATON_PASS", async () => {
+    await game.classicMode.startBattle([ Species.SHUCKLE, Species.SHUCKLE ]);
+    await game.override.moveset([ Moves.POWER_TRICK, Moves.BATON_PASS ]);
+
+    const player = game.scene.getPlayerPokemon()!;
+    player.addTag(BattlerTagType.POWER_TRICK);
+
+    game.move.select(Moves.BATON_PASS);
+    game.doSelectPartyPokemon(1);
+
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    const switchedPlayer = game.scene.getPlayerPokemon()!;
+    const baseATK = switchedPlayer.getStat(Stat.ATK);
+    const baseDEF = switchedPlayer.getStat(Stat.DEF);
+
+    expect(switchedPlayer.getStat(Stat.ATK, false)).toBe(baseDEF);
+    expect(switchedPlayer.getStat(Stat.DEF, false)).toBe(baseATK);
+    expect(switchedPlayer.getTag(BattlerTagType.POWER_TRICK)).toBeDefined();
+  });
+
+  it("should remove effect after using Transform", async () => {
+    await game.classicMode.startBattle([ Species.SHUCKLE, Species.SHUCKLE ]);
+    await game.override.moveset([ Moves.POWER_TRICK, Moves.TRANSFORM ]);
+
+    const player = game.scene.getPlayerPokemon()!;
+    player.addTag(BattlerTagType.POWER_TRICK);
+
+    game.move.select(Moves.TRANSFORM);
+
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    const enemy = game.scene.getEnemyPokemon()!;
+    const baseATK = enemy.getStat(Stat.ATK);
+    const baseDEF = enemy.getStat(Stat.DEF);
+
+    expect(player.getStat(Stat.ATK, false)).toBe(baseATK);
+    expect(player.getStat(Stat.DEF, false)).toBe(baseDEF);
+    expect(player.getTag(BattlerTagType.POWER_TRICK)).toBeUndefined();
+  });
+});