[Move][Ability] Fully Implement Forest's Curse / Trick Or Treat / Mimicry (#4682)

* addedType variable

* basic mimicry implementation

* eslint

* rage

* quick change

* made files

* added mimicry activation message

* test for moves done

* hahahhaha

* done? for now?

* laklhaflhasd

* Apply suggestions from code review

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

* time to start... ughhh

* reflect type

* Added new message

* Update src/field/pokemon.ts

Co-authored-by: PigeonBar <56974298+PigeonBar@users.noreply.github.com>

* Update src/data/ability.ts

Co-authored-by: flx-sta <50131232+flx-sta@users.noreply.github.com>

* added overrides

* some checks

* removed comments

* Apply suggestions from code review

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

---------

Co-authored-by: frutescens <info@laptop>
Co-authored-by: NightKev <34855794+DayKev@users.noreply.github.com>
Co-authored-by: PigeonBar <56974298+PigeonBar@users.noreply.github.com>
Co-authored-by: flx-sta <50131232+flx-sta@users.noreply.github.com>

src/data/ability.ts

@@ -4703,6 +4703,84 @@ export class PreventBypassSpeedChanceAbAttr extends AbAttr {
   }
 }
 
+/**
+ * This applies a terrain-based type change to the Pokemon.
+ * Used by Mimicry.
+ */
+export class TerrainEventTypeChangeAbAttr extends PostSummonAbAttr {
+  constructor() {
+    super(true);
+  }
+
+  override apply(pokemon: Pokemon, _passive: boolean, _simulated: boolean, _cancelled: Utils.BooleanHolder, _args: any[]): boolean {
+    if (pokemon.isTerastallized()) {
+      return false;
+    }
+    const currentTerrain = pokemon.scene.arena.getTerrainType();
+    const typeChange: Type[] = this.determineTypeChange(pokemon, currentTerrain);
+    if (typeChange.length !== 0) {
+      if (pokemon.summonData.addedType && typeChange.includes(pokemon.summonData.addedType)) {
+        pokemon.summonData.addedType = null;
+      }
+      pokemon.summonData.types = typeChange;
+      pokemon.updateInfo();
+    }
+    return true;
+  }
+
+  /**
+   * Retrieves the type(s) the Pokemon should change to in response to a terrain
+   * @param pokemon
+   * @param currentTerrain {@linkcode TerrainType}
+   * @returns a list of type(s)
+   */
+  private determineTypeChange(pokemon: Pokemon, currentTerrain: TerrainType): Type[] {
+    const typeChange: Type[] = [];
+    switch (currentTerrain) {
+      case TerrainType.ELECTRIC:
+        typeChange.push(Type.ELECTRIC);
+        break;
+      case TerrainType.MISTY:
+        typeChange.push(Type.FAIRY);
+        break;
+      case TerrainType.GRASSY:
+        typeChange.push(Type.GRASS);
+        break;
+      case TerrainType.PSYCHIC:
+        typeChange.push(Type.PSYCHIC);
+        break;
+      default:
+        pokemon.getTypes(false, false, true).forEach(t => {
+          typeChange.push(t);
+        });
+        break;
+    }
+    return typeChange;
+  }
+
+  /**
+   * Checks if the Pokemon should change types if summoned into an active terrain
+   * @returns `true` if there is an active terrain requiring a type change | `false` if not
+   */
+  override applyPostSummon(pokemon: Pokemon, passive: boolean, simulated: boolean, args: any[]): boolean | Promise<boolean> {
+    if (pokemon.scene.arena.getTerrainType() !== TerrainType.NONE) {
+      return this.apply(pokemon, passive, simulated, new Utils.BooleanHolder(false), []);
+    }
+    return false;
+  }
+
+  override getTriggerMessage(pokemon: Pokemon, abilityName: string, ...args: any[]) {
+    const currentTerrain = pokemon.scene.arena.getTerrainType();
+    const pokemonNameWithAffix = getPokemonNameWithAffix(pokemon);
+    if (currentTerrain === TerrainType.NONE) {
+      return i18next.t("abilityTriggers:pokemonTypeChangeRevert", { pokemonNameWithAffix });
+    } else {
+      const moveType = i18next.t(`pokemonInfo:Type.${Type[this.determineTypeChange(pokemon, currentTerrain)[0]]}`);
+      return i18next.t("abilityTriggers:pokemonTypeChange", { pokemonNameWithAffix, moveType });
+    }
+  }
+}
+
 async function applyAbAttrsInternal<TAttr extends AbAttr>(
   attrType: Constructor<TAttr>,
   pokemon: Pokemon | null,
@@ -5767,7 +5845,7 @@ export function initAbilities() {
     new Ability(Abilities.POWER_SPOT, 8)
       .attr(AllyMoveCategoryPowerBoostAbAttr, [ MoveCategory.SPECIAL, MoveCategory.PHYSICAL ], 1.3),
     new Ability(Abilities.MIMICRY, 8)
-      .unimplemented(),
+      .attr(TerrainEventTypeChangeAbAttr),
     new Ability(Abilities.SCREEN_CLEANER, 8)
       .attr(PostSummonRemoveArenaTagAbAttr, [ ArenaTagType.AURORA_VEIL, ArenaTagType.LIGHT_SCREEN, ArenaTagType.REFLECT ]),
     new Ability(Abilities.STEELY_SPIRIT, 8)

src/data/move.ts

@@ -5858,6 +5858,9 @@ export class RemoveTypeAttr extends MoveEffectAttr {
 
     const userTypes = user.getTypes(true);
     const modifiedTypes = userTypes.filter(type => type !== this.removedType);
+    if (modifiedTypes.length === 0) {
+      modifiedTypes.push(Type.UNKNOWN);
+    }
     user.summonData.types = modifiedTypes;
     user.updateInfo();
 
@@ -5880,7 +5883,11 @@ export class CopyTypeAttr extends MoveEffectAttr {
       return false;
     }
 
-    user.summonData.types = target.getTypes(true);
+    const targetTypes = target.getTypes(true);
+    if (targetTypes.includes(Type.UNKNOWN) && targetTypes.indexOf(Type.UNKNOWN) > -1) {
+      targetTypes[targetTypes.indexOf(Type.UNKNOWN)] = Type.NORMAL;
+    }
+    user.summonData.types = targetTypes;
     user.updateInfo();
 
     user.scene.queueMessage(i18next.t("moveTriggers:copyType", { pokemonName: getPokemonNameWithAffix(user), targetPokemonName: getPokemonNameWithAffix(target) }));
@@ -5889,7 +5896,7 @@ export class CopyTypeAttr extends MoveEffectAttr {
   }
 
   getCondition(): MoveConditionFunc {
-    return (user, target, move) => target.getTypes()[0] !== Type.UNKNOWN;
+    return (user, target, move) => target.getTypes()[0] !== Type.UNKNOWN || target.summonData.addedType !== null;
   }
 }
 
@@ -5947,11 +5954,7 @@ export class AddTypeAttr extends MoveEffectAttr {
   }
 
   apply(user: Pokemon, target: Pokemon, move: Move, args: any[]): boolean {
-    const types = target.getTypes().slice(0, 2).filter(t => t !== Type.UNKNOWN); // TODO: Figure out some way to actually check if another version of this effect is already applied
+    target.summonData.addedType = this.type;
-    if (this.type !== Type.UNKNOWN) {
-      types.push(this.type);
-    }
-    target.summonData.types = types;
     target.updateInfo();
 
     user.scene.queueMessage(i18next.t("moveTriggers:addType", { typeName: i18next.t(`pokemonInfo:Type.${Type[this.type]}`), pokemonName: getPokemonNameWithAffix(target) }));
@@ -8983,8 +8986,7 @@ export function initMoves() {
       .ignoresProtect()
       .ignoresVirtual(),
     new StatusMove(Moves.TRICK_OR_TREAT, Type.GHOST, 100, 20, -1, 0, 6)
-      .attr(AddTypeAttr, Type.GHOST)
+      .attr(AddTypeAttr, Type.GHOST),
-      .edgeCase(), // Weird interaction with Forest's Curse, reflect type, burn up
     new StatusMove(Moves.NOBLE_ROAR, Type.NORMAL, 100, 30, -1, 0, 6)
       .attr(StatStageChangeAttr, [ Stat.ATK, Stat.SPATK ], -1)
       .soundBased(),
@@ -8996,8 +8998,7 @@ export function initMoves() {
       .target(MoveTarget.ALL_NEAR_OTHERS)
       .triageMove(),
     new StatusMove(Moves.FORESTS_CURSE, Type.GRASS, 100, 20, -1, 0, 6)
-      .attr(AddTypeAttr, Type.GRASS)
+      .attr(AddTypeAttr, Type.GRASS),
-      .edgeCase(), // Weird interaction with Trick or Treat, reflect type, burn up
     new AttackMove(Moves.PETAL_BLIZZARD, Type.GRASS, MoveCategory.PHYSICAL, 90, 100, 15, -1, 0, 6)
       .windMove()
       .makesContact(false)

src/field/arena.ts

@@ -10,7 +10,14 @@ import Move from "#app/data/move";
 import { ArenaTag, ArenaTagSide, ArenaTrapTag, getArenaTag } from "#app/data/arena-tag";
 import { BattlerIndex } from "#app/battle";
 import { Terrain, TerrainType } from "#app/data/terrain";
-import { applyPostTerrainChangeAbAttrs, applyPostWeatherChangeAbAttrs, PostTerrainChangeAbAttr, PostWeatherChangeAbAttr } from "#app/data/ability";
+import {
+  applyAbAttrs,
+  applyPostTerrainChangeAbAttrs,
+  applyPostWeatherChangeAbAttrs,
+  PostTerrainChangeAbAttr,
+  PostWeatherChangeAbAttr,
+  TerrainEventTypeChangeAbAttr
+} from "#app/data/ability";
 import Pokemon from "#app/field/pokemon";
 import Overrides from "#app/overrides";
 import { TagAddedEvent, TagRemovedEvent, TerrainChangedEvent, WeatherChangedEvent } from "#app/events/arena";
@@ -387,6 +394,7 @@ export class Arena {
     this.scene.getField(true).filter(p => p.isOnField()).map(pokemon => {
       pokemon.findAndRemoveTags(t => "terrainTypes" in t && !(t.terrainTypes as TerrainType[]).find(t => t === terrain));
       applyPostTerrainChangeAbAttrs(PostTerrainChangeAbAttr, pokemon, terrain);
+      applyAbAttrs(TerrainEventTypeChangeAbAttr, pokemon, null, false);
     });
 
     return true;

src/field/pokemon.ts

@@ -1258,6 +1258,11 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
       }
     }
 
+    // the type added to Pokemon from moves like Forest's Curse or Trick Or Treat
+    if (!ignoreOverride && this.summonData && this.summonData.addedType && !types.includes(this.summonData.addedType)) {
+      types.push(this.summonData.addedType);
+    }
+
     // If both types are the same (can happen in weird custom typing scenarios), reduce to single type
     if (types.length > 1 && types[0] === types[1]) {
       types.splice(0, 1);
@@ -5100,6 +5105,7 @@ export class PokemonSummonData {
   public moveset: (PokemonMove | null)[];
   // If not initialized this value will not be populated from save data.
   public types: Type[] = [];
+  public addedType: Type | null = null;
 }
 
 export class PokemonBattleData {

src/test/abilities/mimicry.test.ts

@@ -0,0 +1,91 @@
+import { Abilities } from "#enums/abilities";
+import { Moves } from "#enums/moves";
+import { Species } from "#enums/species";
+import { Type } from "#app/data/type";
+import GameManager from "#test/utils/gameManager";
+import Phaser from "phaser";
+import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
+
+describe("Abilities - Mimicry", () => {
+  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
+      .moveset([ Moves.SPLASH ])
+      .ability(Abilities.MIMICRY)
+      .battleType("single")
+      .disableCrits()
+      .enemySpecies(Species.MAGIKARP)
+      .enemyMoveset(Moves.SPLASH);
+  });
+
+  it("Mimicry activates after the Pokémon with Mimicry is switched in while terrain is present, or whenever there is a change in terrain", async () => {
+    game.override.enemyAbility(Abilities.MISTY_SURGE);
+    await game.classicMode.startBattle([ Species.FEEBAS, Species.ABRA ]);
+
+    const [ playerPokemon1, playerPokemon2 ] = game.scene.getParty();
+    game.move.select(Moves.SPLASH);
+    await game.toNextTurn();
+    expect(playerPokemon1.getTypes().includes(Type.FAIRY)).toBe(true);
+
+    game.doSwitchPokemon(1);
+    await game.toNextTurn();
+
+    expect(playerPokemon2.getTypes().includes(Type.FAIRY)).toBe(true);
+  });
+
+  it("Pokemon should revert back to its original, root type once terrain ends", async () => {
+    game.override
+      .moveset([ Moves.SPLASH, Moves.TRANSFORM ])
+      .enemyAbility(Abilities.MIMICRY)
+      .enemyMoveset([ Moves.SPLASH, Moves.PSYCHIC_TERRAIN ]);
+    await game.classicMode.startBattle([ Species.REGIELEKI ]);
+
+    const playerPokemon = game.scene.getPlayerPokemon();
+    game.move.select(Moves.TRANSFORM);
+    await game.forceEnemyMove(Moves.PSYCHIC_TERRAIN);
+    await game.toNextTurn();
+    expect(playerPokemon?.getTypes().includes(Type.PSYCHIC)).toBe(true);
+
+    if (game.scene.arena.terrain) {
+      game.scene.arena.terrain.turnsLeft = 1;
+    }
+
+    game.move.select(Moves.SPLASH);
+    await game.forceEnemyMove(Moves.SPLASH);
+    await game.toNextTurn();
+    expect(playerPokemon?.getTypes().includes(Type.ELECTRIC)).toBe(true);
+  });
+
+  it("If the Pokemon is under the effect of a type-adding move and an equivalent terrain activates, the move's effect disappears", async () => {
+    game.override
+      .enemyMoveset([ Moves.FORESTS_CURSE, Moves.GRASSY_TERRAIN ]);
+    await game.classicMode.startBattle([ Species.FEEBAS ]);
+
+    const playerPokemon = game.scene.getPlayerPokemon();
+    game.move.select(Moves.SPLASH);
+    await game.forceEnemyMove(Moves.FORESTS_CURSE);
+    await game.toNextTurn();
+
+    expect(playerPokemon?.summonData.addedType).toBe(Type.GRASS);
+
+    game.move.select(Moves.SPLASH);
+    await game.forceEnemyMove(Moves.GRASSY_TERRAIN);
+    await game.phaseInterceptor.to("TurnEndPhase");
+
+    expect(playerPokemon?.summonData.addedType).toBeNull();
+    expect(playerPokemon?.getTypes().includes(Type.GRASS)).toBe(true);
+  });
+});

src/test/moves/forests_curse.test.ts

@@ -0,0 +1,47 @@
+import { Abilities } from "#enums/abilities";
+import { Moves } from "#enums/moves";
+import { Species } from "#enums/species";
+import { Type } from "#app/data/type";
+import GameManager from "#test/utils/gameManager";
+import Phaser from "phaser";
+import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
+
+describe("Moves - Forest's Curse", () => {
+  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
+      .moveset([ Moves.FORESTS_CURSE, Moves.TRICK_OR_TREAT ])
+      .ability(Abilities.BALL_FETCH)
+      .battleType("single")
+      .disableCrits()
+      .enemySpecies(Species.MAGIKARP)
+      .enemyAbility(Abilities.BALL_FETCH)
+      .enemyMoveset(Moves.SPLASH);
+  });
+
+  it("will replace the added type from Trick Or Treat", async () => {
+    await game.classicMode.startBattle([ Species.FEEBAS ]);
+
+    const enemyPokemon = game.scene.getEnemyPokemon();
+    game.move.select(Moves.TRICK_OR_TREAT);
+    await game.phaseInterceptor.to("TurnEndPhase");
+    expect(enemyPokemon!.summonData.addedType).toBe(Type.GHOST);
+
+    game.move.select(Moves.FORESTS_CURSE);
+    await game.phaseInterceptor.to("TurnEndPhase");
+    expect(enemyPokemon?.summonData.addedType).toBe(Type.GRASS);
+  });
+});

src/test/moves/reflect_type.test.ts

@@ -0,0 +1,59 @@
+import { Abilities } from "#enums/abilities";
+import { Moves } from "#enums/moves";
+import { Species } from "#enums/species";
+import { Type } from "#app/data/type";
+import GameManager from "#test/utils/gameManager";
+import Phaser from "phaser";
+import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
+
+describe("Moves - Reflect Type", () => {
+  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
+      .ability(Abilities.BALL_FETCH)
+      .battleType("single")
+      .disableCrits()
+      .enemyAbility(Abilities.BALL_FETCH);
+  });
+
+  it("will make the user Normal/Grass if targetting a typeless Pokemon affected by Forest's Curse", async () => {
+    game.override
+      .moveset([ Moves.FORESTS_CURSE, Moves.REFLECT_TYPE ])
+      .startingLevel(60)
+      .enemySpecies(Species.CHARMANDER)
+      .enemyMoveset([ Moves.BURN_UP, Moves.SPLASH ]);
+    await game.classicMode.startBattle([ Species.FEEBAS ]);
+
+    const playerPokemon = game.scene.getPlayerPokemon();
+    const enemyPokemon = game.scene.getEnemyPokemon();
+
+    game.move.select(Moves.SPLASH);
+    await game.forceEnemyMove(Moves.BURN_UP);
+    await game.toNextTurn();
+
+    game.move.select(Moves.FORESTS_CURSE);
+    await game.forceEnemyMove(Moves.SPLASH);
+    await game.toNextTurn();
+    expect(enemyPokemon?.getTypes().includes(Type.UNKNOWN)).toBe(true);
+    expect(enemyPokemon?.getTypes().includes(Type.GRASS)).toBe(true);
+
+    game.move.select(Moves.REFLECT_TYPE);
+    await game.forceEnemyMove(Moves.SPLASH);
+    await game.phaseInterceptor.to("TurnEndPhase");
+    expect(playerPokemon?.getTypes()[0]).toBe(Type.NORMAL);
+    expect(playerPokemon?.getTypes().includes(Type.GRASS)).toBe(true);
+  });
+});

src/test/moves/trick_or_treat.test.ts

@@ -0,0 +1,47 @@
+import { Abilities } from "#enums/abilities";
+import { Moves } from "#enums/moves";
+import { Species } from "#enums/species";
+import { Type } from "#app/data/type";
+import GameManager from "#test/utils/gameManager";
+import Phaser from "phaser";
+import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
+
+describe("Moves - Trick Or Treat", () => {
+  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
+      .moveset([ Moves.FORESTS_CURSE, Moves.TRICK_OR_TREAT ])
+      .ability(Abilities.BALL_FETCH)
+      .battleType("single")
+      .disableCrits()
+      .enemySpecies(Species.MAGIKARP)
+      .enemyAbility(Abilities.BALL_FETCH)
+      .enemyMoveset(Moves.SPLASH);
+  });
+
+  it("will replace added type from Forest's Curse", async () => {
+    await game.classicMode.startBattle([ Species.FEEBAS ]);
+
+    const enemyPokemon = game.scene.getEnemyPokemon();
+    game.move.select(Moves.FORESTS_CURSE);
+    await game.phaseInterceptor.to("TurnEndPhase");
+    expect(enemyPokemon!.summonData.addedType).toBe(Type.GRASS);
+
+    game.move.select(Moves.TRICK_OR_TREAT);
+    await game.phaseInterceptor.to("TurnEndPhase");
+    expect(enemyPokemon?.summonData.addedType).toBe(Type.GHOST);
+  });
+});