[Bug] Fix Make It Rain not applying effect on KO (#2670)

src/data/move.ts

@@ -5513,11 +5513,21 @@ const userSleptOrComatoseCondition: MoveConditionFunc = (user: Pokemon, target:
 
 const targetSleptOrComatoseCondition: MoveConditionFunc = (user: Pokemon, target: Pokemon, move: Move) =>  target.status?.effect === StatusEffect.SLEEP || target.hasAbility(Abilities.COMATOSE);
 
+/**
+ * Condition to apply effects only upon applying the move to its last target.
+ * Currently only used for Make It Rain.
+ * @param {Pokemon} user The user of the move.
+ * @param {Pokemon} target The current target of the move.
+ * @param {Move} move The move to which this condition applies.
+ * @returns true if the target is the last target to which the move applies.
+ */
 const lastTargetOnlyCondition: MoveConditionFunc = (user: Pokemon, target: Pokemon, move: Move) => {
   const effectPhase = user.scene.getCurrentPhase();
+  const targetIndex = target.getFieldIndex() + (target.isPlayer() ? 0 : BattlerIndex.ENEMY);
 
   if (effectPhase instanceof MoveEffectPhase) {
-    return target === effectPhase.getTargets().at(-1);
+    const activeTargets = effectPhase.getTargets();
+    return (activeTargets.length === 0 || targetIndex >= activeTargets.at(-1).getBattlerIndex());
   }
   return false;
 };

src/test/moves/make_it_rain.test.ts

@@ -6,6 +6,7 @@ import { Species } from "#enums/species";
 import {
   CommandPhase,
   MoveEndPhase,
+  StatChangePhase,
 } from "#app/phases";
 import { Moves } from "#enums/moves";
 import { getMovePosition } from "#app/test/utils/gameManagerUtils";
@@ -57,4 +58,25 @@ describe("Moves - Make It Rain", () => {
 
     expect(playerPokemon[0].summonData.battleStats[BattleStat.SPATK]).toBe(-1);
   });
+
+  it("should apply effects even if the target faints", async () => {
+    vi.spyOn(overrides, "OPP_LEVEL_OVERRIDE", "get").mockReturnValue(1); // ensures the enemy will faint
+    vi.spyOn(overrides, "DOUBLE_BATTLE_OVERRIDE", "get").mockReturnValue(false);
+    vi.spyOn(overrides, "SINGLE_BATTLE_OVERRIDE", "get").mockReturnValue(true);
+
+    await game.startBattle([Species.CHARIZARD]);
+
+    const playerPokemon = game.scene.getPlayerPokemon();
+    expect(playerPokemon).toBeDefined();
+
+    const enemyPokemon = game.scene.getEnemyPokemon();
+    expect(enemyPokemon).toBeDefined();
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.MAKE_IT_RAIN));
+
+    await game.phaseInterceptor.to(StatChangePhase);
+
+    expect(enemyPokemon.isFainted()).toBe(true);
+    expect(playerPokemon.summonData.battleStats[BattleStat.SPATK]).toBe(-1);
+  });
 });