[Bug] Unblock priority spread under Psychic Terrain (#6136)

Unblock priority spread under Psychic Terrain

Co-authored-by: Acelynn Zhang <acelynnzhang@Acelynns-MacBook-Pro.local>

src/data/moves/move-utils.ts

@@ -27,6 +27,28 @@ export function isFieldTargeted(move: Move): boolean {
   return false;
 }
 
+/**
+ * Determine whether a move is a spread move.
+ *
+ * @param move - The {@linkcode Move} to check
+ * @returns Whether {@linkcode move} is spread-targeted.
+ * @remarks
+ * Examples include:
+ * - Moves targeting all adjacent Pokemon (like Surf)
+ * - Moves targeting all adjacent enemies (like Air Cutter)
+ */
+
+export function isSpreadMove(move: Move): boolean {
+  switch (move.moveTarget) {
+    case MoveTarget.ALL_ENEMIES:
+    case MoveTarget.ALL_NEAR_ENEMIES:
+    case MoveTarget.ALL_OTHERS:
+    case MoveTarget.ALL_NEAR_OTHERS:
+      return true;
+  }
+  return false;
+}
+
 export function getMoveTargets(user: Pokemon, move: MoveId, replaceTarget?: MoveTarget): MoveTargetSet {
   const variableTarget = new NumberHolder(0);
   user.getOpponents(false).forEach(p => applyMoveAttrs("VariableTargetAttr", user, p, allMoves[move], variableTarget));

src/data/terrain.ts

@@ -3,6 +3,7 @@ import type { BattlerIndex } from "#enums/battler-index";
 import { PokemonType } from "#enums/pokemon-type";
 import type { Pokemon } from "#field/pokemon";
 import type { Move } from "#moves/move";
+import { isFieldTargeted, isSpreadMove } from "#moves/move-utils";
 import i18next from "i18next";
 
 export enum TerrainType {
@@ -60,13 +61,19 @@ export class Terrain {
   isMoveTerrainCancelled(user: Pokemon, targets: BattlerIndex[], move: Move): boolean {
     switch (this.terrainType) {
       case TerrainType.PSYCHIC:
-        if (!move.hasAttr("ProtectAttr")) {
-          // Cancels move if the move has positive priority and targets a Pokemon grounded on the Psychic Terrain
-          return (
-            move.getPriority(user) > 0 &&
-            user.getOpponents(true).some(o => targets.includes(o.getBattlerIndex()) && o.isGrounded())
-          );
-        }
+        // Cf https://bulbapedia.bulbagarden.net/wiki/Psychic_Terrain_(move)#Generation_VII
+        // Psychic terrain will only cancel a move if it:
+        return (
+          // ... is neither spread nor field-targeted,
+          !isFieldTargeted(move) &&
+          !isSpreadMove(move) &&
+          // .. has positive final priority,
+          move.getPriority(user) > 0 &&
+          // ...and is targeting at least 1 grounded opponent
+          user
+            .getOpponents(true)
+            .some(o => targets.includes(o.getBattlerIndex()) && o.isGrounded())
+        );
     }
 
     return false;

test/arena/psychic-terrain.test.ts

@@ -0,0 +1,59 @@
+import { AbilityId } from "#enums/ability-id";
+import { MoveId } from "#enums/move-id";
+import { SpeciesId } from "#enums/species-id";
+import { StatusEffect } from "#enums/status-effect";
+import { WeatherType } from "#enums/weather-type";
+import { GameManager } from "#test/test-utils/game-manager";
+import Phaser from "phaser";
+import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
+
+describe("Arena - Psychic Terrain", () => {
+  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
+      .battleStyle("single")
+      .criticalHits(false)
+      .enemyLevel(1)
+      .enemySpecies(SpeciesId.SHUCKLE)
+      .enemyAbility(AbilityId.STURDY)
+      .enemyMoveset(MoveId.SPLASH)
+      .moveset([MoveId.PSYCHIC_TERRAIN, MoveId.RAIN_DANCE, MoveId.DARK_VOID])
+      .ability(AbilityId.NO_GUARD);
+  });
+
+  it("Dark Void with Prankster is not blocked", async () => {
+    await game.classicMode.startBattle([SpeciesId.MAGIKARP]);
+
+    game.move.select(MoveId.PSYCHIC_TERRAIN);
+    await game.toNextTurn();
+
+    game.move.select(MoveId.DARK_VOID);
+    await game.toEndOfTurn();
+
+    expect(game.scene.getEnemyPokemon()!.status?.effect).toBe(StatusEffect.SLEEP);
+  });
+
+  it("Rain Dance with Prankster is not blocked", async () => {
+    await game.classicMode.startBattle([SpeciesId.MAGIKARP]);
+
+    game.move.select(MoveId.PSYCHIC_TERRAIN);
+    await game.toNextTurn();
+
+    game.move.select(MoveId.RAIN_DANCE);
+    await game.toEndOfTurn();
+
+    expect(game.scene.arena.weather?.weatherType).toBe(WeatherType.RAIN);
+  });
+});