refactored code as requested

pls tell me this isn't too much tech debt now
(also RIP unnecessarily convoluted cube roots, you will be missed)

src/data/move.ts

@@ -9,7 +9,7 @@ import { Constructor, NumberHolder } from "#app/utils";
 import * as Utils from "../utils";
 import { WeatherType } from "#enums/weather-type";
 import { ArenaTagSide, ArenaTrapTag, WeakenMoveTypeTag } from "./arena-tag";
-import { allAbilities, AllyMoveCategoryPowerBoostAbAttr, applyAbAttrs, applyPostAttackAbAttrs, applyPostItemLostAbAttrs, applyPreAttackAbAttrs, applyPreDefendAbAttrs, BlockItemTheftAbAttr, BlockNonDirectDamageAbAttr, BlockOneHitKOAbAttr, BlockRecoilDamageAttr, ChangeMovePriorityAbAttr, ConfusionOnStatusEffectAbAttr, FieldMoveTypePowerBoostAbAttr, FieldPreventExplosiveMovesAbAttr, ForceSwitchOutImmunityAbAttr, HealFromBerryUseAbAttr, IgnoreContactAbAttr, IgnoreMoveEffectsAbAttr, IgnoreProtectOnContactAbAttr, InfiltratorAbAttr, MaxMultiHitAbAttr, MoveAbilityBypassAbAttr, MoveEffectChanceMultiplierAbAttr, MoveTypeChangeAbAttr, PostDamageForceSwitchAbAttr, PostItemLostAbAttr, ReverseDrainAbAttr, UncopiableAbilityAbAttr, UnsuppressableAbilityAbAttr, UnswappableAbilityAbAttr, UserFieldMoveTypePowerBoostAbAttr, VariableMovePowerAbAttr, WonderSkinAbAttr } from "./ability";
+import { AddSecondStrikeAbAttr, allAbilities, AllyMoveCategoryPowerBoostAbAttr, applyAbAttrs, applyPostAttackAbAttrs, applyPostItemLostAbAttrs, applyPreAttackAbAttrs, applyPreDefendAbAttrs, BlockItemTheftAbAttr, BlockNonDirectDamageAbAttr, BlockOneHitKOAbAttr, BlockRecoilDamageAttr, ChangeMovePriorityAbAttr, ConfusionOnStatusEffectAbAttr, FieldMoveTypePowerBoostAbAttr, FieldPreventExplosiveMovesAbAttr, ForceSwitchOutImmunityAbAttr, HealFromBerryUseAbAttr, IgnoreContactAbAttr, IgnoreMoveEffectsAbAttr, IgnoreProtectOnContactAbAttr, InfiltratorAbAttr, MaxMultiHitAbAttr, MoveAbilityBypassAbAttr, MoveEffectChanceMultiplierAbAttr, MoveTypeChangeAbAttr, PostDamageForceSwitchAbAttr, PostItemLostAbAttr, ReverseDrainAbAttr, UncopiableAbilityAbAttr, UnsuppressableAbilityAbAttr, UnswappableAbilityAbAttr, UserFieldMoveTypePowerBoostAbAttr, VariableMovePowerAbAttr, WonderSkinAbAttr } from "./ability";
 import { AttackTypeBoosterModifier, BerryModifier, PokemonHeldItemModifier, PokemonMoveAccuracyBoosterModifier, PokemonMultiHitModifier, PreserveBerryModifier } from "../modifier/modifier";
 import { BattlerIndex, BattleType } from "../battle";
 import { TerrainType } from "./terrain";
@@ -1385,12 +1385,33 @@ export class UserHpDamageAttr extends FixedDamageAttr {
 }
 
 export class TargetHalfHpDamageAttr extends FixedDamageAttr {
+  private targetHp: number; // the final amount of hp we want the target to have
+  private hpAfterFirstAttack: number | null;
   constructor() {
     super(0);
   }
 
   apply(user: Pokemon, target: Pokemon, move: Move, args: any[]): boolean {
-    (args[0] as Utils.IntegerHolder).value = Utils.toDmgValue(target.hp / 2);
+    // first, determine if the hit is coming from multi lens or not
+    const lensCount = user.getHeldItems().find(i => i instanceof PokemonMultiHitModifier)?.getStackCount() ?? 0;
+    if (lensCount <= 0) {
+      // no multi lenses; we can just halve the target's hp and call it a day
+      (args[0] as Utils.NumberHolder).value = Utils.toDmgValue(target.hp / 2);
+      return true;
+    }
+
+    // Figure out what hit # we're on
+    if (user.turnData.hitCount === user.turnData.hitsLeft) {
+      // first hit of move; apply damage as normal and update targetHp accordingly
+      this.targetHp = target.hp * (0.5 ** (user.hasAbilityWithAttr(AddSecondStrikeAbAttr) ? 2 : 1));
+      this.hpAfterFirstAttack = null;
+      (args[0] as Utils.NumberHolder).value = Utils.toDmgValue(target.hp / 2);
+    } else {
+      // all subsequent hits split the damage evenly among themselves
+      this.hpAfterFirstAttack ??= Utils.toDmgValue(target.hp); // nullish coalescing assignment go brrr
+      const totalHits = user.turnData.hitCount - 1;
+      (args[0] as Utils.NumberHolder).value = Utils.toDmgValue((this.hpAfterFirstAttack - this.targetHp) / totalHits);
+    }
 
     return true;
   }

src/field/pokemon.ts

@@ -2622,34 +2622,14 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     const fixedDamage = new Utils.NumberHolder(0);
     applyMoveAttrs(FixedDamageAttr, source, this, move, fixedDamage);
     if (fixedDamage.value) {
-      const lensCount = source.getHeldItems().find(i => i instanceof PokemonMultiHitModifier)?.getStackCount() ?? 0;
+      // Don't apply the multi lens damage penalty for subsequent hits of a hp cutting move
-      // Apply damage fixing for hp cutting moves on multi lens hits (NOT PARENTAL BOND)
+      // those get handled separately in move.ts
-      if (lensCount > 0
+      if (!(move.hasAttr(TargetHalfHpDamageAttr)
-        && move.hasAttr(TargetHalfHpDamageAttr)
+        && source.turnData.hitCount !== source.turnData.hitsLeft)) {
-        && (source.turnData.hitCount === source.turnData.hitsLeft
+        const multiLensMultiplier = new Utils.NumberHolder(1);
-        || source.turnData.hitCount - source.turnData.hitsLeft !== lensCount + 1)) {
+        source.scene.applyModifiers(PokemonMultiHitModifier, source.isPlayer(), source, move.id, null, multiLensMultiplier);
-        // Do some unholy math to make the moves' damage values add up to 50%
+        fixedDamage.value = Utils.toDmgValue(fixedDamage.value * multiLensMultiplier.value);
-        // Values obtained courtesy of WolframAlpha and Desmos Graphing Calculator
-        // (https://www.desmos.com/calculator/wdngrksdfz)
-        let damageMulti = 1;
-        // NOTE: If multi lens ever gets updated (again) this switch case will NEED to be updated alongside it!
-        switch (lensCount) {
-          case 1:
-            damageMulti = 0.558481559888;
-            break;
-          case 2:
-            damageMulti = 0.60875846088;
-            break;
-          default:
-            damageMulti = 0.5;
-            break;
-        }
-
-        fixedDamage.value = this.hp * damageMulti;
       }
-      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,

src/test/items/multi_lens.test.ts

@@ -140,7 +140,7 @@ describe("Items - Multi Lens", () => {
     game.override.startingHeldItems([{ name: "MULTI_LENS", count: 1 }])
       .moveset(Moves.SUPER_FANG)
       .ability(Abilities.COMPOUND_EYES)
-      .enemyLevel(100000)
+      .enemyLevel(1000)
       .enemySpecies(Species.BLISSEY); // allows for unrealistically high levels of accuracy
 
     await game.classicMode.startBattle([ Species.MAGIKARP ]);
@@ -150,7 +150,7 @@ describe("Items - Multi Lens", () => {
     game.move.select(Moves.SUPER_FANG);
     await game.setTurnOrder([ BattlerIndex.PLAYER, BattlerIndex.ENEMY ]);
     await game.phaseInterceptor.to("MoveEndPhase");
-    expect(enemyPokemon.getHpRatio()).toBeCloseTo(0.5, 10); // unrealistically high level of precision
+    expect(enemyPokemon.getHpRatio()).toBeCloseTo(0.5, 5);
   });
 
   it("should result in correct damage for hp% attacks with 2 lenses", async () => {
@@ -158,7 +158,7 @@ describe("Items - Multi Lens", () => {
       .moveset(Moves.SUPER_FANG)
       .ability(Abilities.COMPOUND_EYES)
       .enemyMoveset(Moves.SPLASH)
-      .enemyLevel(100000)
+      .enemyLevel(1000)
       .enemySpecies(Species.BLISSEY); // allows for unrealistically high levels of accuracy
 
     await game.classicMode.startBattle([ Species.MAGIKARP ]);
@@ -168,15 +168,15 @@ describe("Items - Multi Lens", () => {
     game.move.select(Moves.SUPER_FANG);
     await game.setTurnOrder([ BattlerIndex.PLAYER, BattlerIndex.ENEMY ]);
     await game.phaseInterceptor.to("MoveEndPhase");
-    expect(enemyPokemon.getHpRatio()).toBeCloseTo(0.5, 8); // unrealistically high level of precision
+    expect(enemyPokemon.getHpRatio()).toBeCloseTo(0.5, 5);
   });
   it("should result in correct damage for hp% attacks with 2 lenses + Parental Bond", async () => {
-    game.override.startingHeldItems([{ name: "MULTI_LENS", count: 2 },
+    game.override.startingHeldItems([{ name: "MULTI_LENS", count: 2 }])
-      { name: "WIDE_LENS", count: 2 }]) // ensures move always hits
       .moveset(Moves.SUPER_FANG)
       .ability(Abilities.PARENTAL_BOND)
+      .passiveAbility(Abilities.COMPOUND_EYES)
       .enemyMoveset(Moves.SPLASH)
-      .enemyLevel(100000)
+      .enemyLevel(1000)
       .enemySpecies(Species.BLISSEY); // allows for unrealistically high levels of accuracy
 
     await game.classicMode.startBattle([ Species.MAGIKARP ]);
@@ -186,6 +186,6 @@ describe("Items - Multi Lens", () => {
     game.move.select(Moves.SUPER_FANG);
     await game.setTurnOrder([ BattlerIndex.PLAYER, BattlerIndex.ENEMY ]);
     await game.phaseInterceptor.to("MoveEndPhase");
-    expect(enemyPokemon.getHpRatio()).toBeCloseTo(0.25, 8);
+    expect(enemyPokemon.getHpRatio()).toBeCloseTo(0.25, 5);
   });
 });