From 07f08877c18a027b9ff6c473476796b3d57b992b Mon Sep 17 00:00:00 2001
From: PigeonBar <56974298+PigeonBar@users.noreply.github.com>
Date: Sun, 17 Nov 2024 12:16:54 -0500
Subject: [PATCH] [Balance] Multi Lens damage reduction on fixed-damage moves
 (#4896)

---
 src/field/pokemon.ts                     |  4 ++++
 src/modifier/modifier.ts                 | 16 +++++++++++----
 src/test/abilities/parental_bond.test.ts |  2 +-
 src/test/items/multi_lens.test.ts        | 25 ++++++++++++++++++++++--
 4 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/src/field/pokemon.ts b/src/field/pokemon.ts
index f9e7d7d1cad..f14fc954c84 100644
--- a/src/field/pokemon.ts
+++ b/src/field/pokemon.ts
@@ -2622,6 +2622,10 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     const fixedDamage = new Utils.IntegerHolder(0);
     applyMoveAttrs(FixedDamageAttr, source, this, move, fixedDamage);
     if (fixedDamage.value) {
+      const multiLensMultiplier = new Utils.NumberHolder(1);
+      source.scene.applyModifiers(PokemonMultiHitModifier, source.isPlayer(), source, move.id, null, multiLensMultiplier);
+      fixedDamage.value = Utils.toDmgValue(fixedDamage.value * multiLensMultiplier.value);
+
       return {
         cancelled: false,
         result: HitResult.EFFECTIVE,
diff --git a/src/modifier/modifier.ts b/src/modifier/modifier.ts
index bbd1763cd84..5e5246269a3 100644
--- a/src/modifier/modifier.ts
+++ b/src/modifier/modifier.ts
@@ -2727,10 +2727,18 @@ export class PokemonMultiHitModifier extends PokemonHeldItemModifier {
    * Additional strikes beyond that are given a 0.25x damage multiplier
    */
   private applyDamageModifier(pokemon: Pokemon, damageMultiplier: NumberHolder): boolean {
-    damageMultiplier.value = (pokemon.turnData.hitsLeft === pokemon.turnData.hitCount)
-      ? (1 - (0.25 * this.getStackCount()))
-      : 0.25;
-    return true;
+    if (pokemon.turnData.hitsLeft === pokemon.turnData.hitCount) {
+      // Reduce first hit by 25% for each stack count
+      damageMultiplier.value *= 1 - 0.25 * this.getStackCount();
+      return true;
+    } else if (pokemon.turnData.hitCount - pokemon.turnData.hitsLeft !== this.getStackCount() + 1) {
+      // Deal 25% damage for each remaining Multi Lens hit
+      damageMultiplier.value *= 0.25;
+      return true;
+    } else {
+      // An extra hit not caused by Multi Lens -- assume it is Parental Bond
+      return false;
+    }
   }
 
   getMaxHeldItemCount(pokemon: Pokemon): number {
diff --git a/src/test/abilities/parental_bond.test.ts b/src/test/abilities/parental_bond.test.ts
index 4189941a51e..10048a774cd 100644
--- a/src/test/abilities/parental_bond.test.ts
+++ b/src/test/abilities/parental_bond.test.ts
@@ -313,7 +313,7 @@ describe("Abilities - Parental Bond", () => {
 
       await game.phaseInterceptor.to("MoveEndPhase", false);
 
-      expect(enemyPokemon.hp).toBe(enemyStartingHp - 300);
+      expect(enemyPokemon.hp).toBe(enemyStartingHp - 200);
     }
   );
 
diff --git a/src/test/items/multi_lens.test.ts b/src/test/items/multi_lens.test.ts
index d389ca70555..c5e60c9f9e5 100644
--- a/src/test/items/multi_lens.test.ts
+++ b/src/test/items/multi_lens.test.ts
@@ -32,8 +32,8 @@ describe("Items - Multi Lens", () => {
       .enemySpecies(Species.SNORLAX)
       .enemyAbility(Abilities.BALL_FETCH)
       .enemyMoveset(Moves.SPLASH)
-      .startingLevel(100)
-      .enemyLevel(100);
+      .startingLevel(99) // Check for proper rounding on Seismic Toss damage reduction
+      .enemyLevel(99);
   });
 
   it.each([
@@ -114,4 +114,25 @@ describe("Items - Multi Lens", () => {
 
     expect(magikarp.turnData.hitCount).toBe(2);
   });
+
+  it("should enhance fixed-damage moves while also applying damage reduction", async () => {
+    game.override.startingHeldItems([{ name: "MULTI_LENS", count: 1 }])
+      .moveset(Moves.SEISMIC_TOSS);
+
+    await game.classicMode.startBattle([ Species.MAGIKARP ]);
+
+    const playerPokemon = game.scene.getPlayerPokemon()!;
+    const enemyPokemon = game.scene.getEnemyPokemon()!;
+    const spy = vi.spyOn(enemyPokemon, "getAttackDamage");
+
+    game.move.select(Moves.SEISMIC_TOSS);
+    await game.setTurnOrder([ BattlerIndex.PLAYER, BattlerIndex.ENEMY ]);
+
+    await game.phaseInterceptor.to("MoveEndPhase");
+    const damageResults = spy.mock.results.map(result => result.value?.damage);
+
+    expect(damageResults).toHaveLength(2);
+    expect(damageResults[0]).toBe(Math.floor(playerPokemon.level * 0.75));
+    expect(damageResults[1]).toBe(Math.floor(playerPokemon.level * 0.25));
+  });
 });