Address typing issue in safeguard test

Also removed stat drop ability application from cancelling ME stat boost effects

src/@types/ability-types.ts

@@ -1,14 +1,14 @@
-import type { AbAttr } from "#app/data/abilities/ability";
 import type Move from "#app/data/moves/move";
 import type Pokemon from "#app/field/pokemon";
 import type { BattleStat } from "#enums/stat";
 import type { AbAttrConstructorMap } from "#app/data/abilities/ability";
 
-// Intentionally re-export all types from the ability attributes module
+// intentionally re-export all types from abilities to have this be the centralized place to import ability types
 export type * from "#app/data/abilities/ability";
 
-export type AbAttrApplyFunc<TAttr extends AbAttr> = (attr: TAttr, passive: boolean, ...args: any[]) => void;
-export type AbAttrSuccessFunc<TAttr extends AbAttr> = (attr: TAttr, passive: boolean, ...args: any[]) => boolean;
+// biome-ignore lint/correctness/noUnusedImports: Used in a tsdoc comment
+import type { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+
 export type AbAttrCondition = (pokemon: Pokemon) => boolean;
 export type PokemonAttackCondition = (user: Pokemon | null, target: Pokemon | null, move: Move) => boolean;
 export type PokemonDefendCondition = (target: Pokemon, user: Pokemon, move: Move) => boolean;
@@ -25,3 +25,22 @@ export type AbAttrString = keyof AbAttrConstructorMap;
 export type AbAttrMap = {
   [K in keyof AbAttrConstructorMap]: InstanceType<AbAttrConstructorMap[K]>;
 };
+
+/**
+ * Subset of ability attribute classes that may be passed to {@linkcode applyAbAttrs } method
+ *
+ * @remarks
+ * Our AbAttr classes violate Liskov Substitution Principle.
+ *
+ * AbAttrs that are not in this have subclasses with apply methods requiring different parameters than
+ * the base apply method.
+ *
+ * Such attributes may not be passed to the {@linkcode applyAbAttrs} method
+ */
+export type CallableAbAttrString =
+  | Exclude<AbAttrString, "PreDefendAbAttr" | "PreAttackAbAttr">
+  | "PreApplyBattlerTagAbAttr";
+
+export type AbAttrParamMap = {
+  [K in keyof AbAttrMap]: Parameters<AbAttrMap[K]["apply"]>[0];
+};

src/@types/type-helpers.ts

@@ -0,0 +1,32 @@
+/*
+ * A collection of custom utility types that aid in type checking and ensuring strict type conformity
+ */
+
+// biome-ignore lint/correctness/noUnusedImports: Used in a tsdoc comment
+import type { AbAttr } from "./ability-types";
+
+/** Exactly matches the type of the argument, preventing adding additional properties.
+ * ⚠️ Should never be used with `extends`, as this will nullify the exactness of the type.
+ * As an example, used to ensure that the parameters of {@linkcode AbAttr#canApply} and {@linkcode AbAttr#getTriggerMessage} are compatible with
+ * the type of the apply method
+ *
+ * @typeParam T - The type to match exactly
+ */
+export type Exact<T> = {
+  [K in keyof T]: T[K];
+};
+
+/**
+ * Type hint that indicates that the type is intended to be closed to a specific shape.
+ * Does not actually do anything special, is really just an alias for X.
+ *
+ */
+export type Closed<X> = X;
+
+/**
+ * Remove `readonly` from all properties of the provided type
+ * @typeParam T - The type to make mutable
+ */
+export type Mutable<T> = {
+  -readonly [P in keyof T]: T[P];
+};

src/battle-scene.ts

@@ -67,7 +67,7 @@ import { modifierTypes } from "./data/data-lists";
 import { getModifierPoolForType } from "./utils/modifier-utils";
 import { ModifierPoolType } from "#enums/modifier-pool-type";
 import AbilityBar from "#app/ui/ability-bar";
-import { applyAbAttrs, applyPostBattleInitAbAttrs, applyPostItemLostAbAttrs } from "./data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "./data/abilities/apply-ab-attrs";
 import { allAbilities } from "./data/data-lists";
 import type { FixedBattleConfig } from "#app/battle";
 import Battle from "#app/battle";
@@ -1256,7 +1256,7 @@ export default class BattleScene extends SceneBase {
     const doubleChance = new NumberHolder(newWaveIndex % 10 === 0 ? 32 : 8);
     this.applyModifiers(DoubleBattleChanceBoosterModifier, true, doubleChance);
     for (const p of playerField) {
-      applyAbAttrs("DoubleBattleChanceAbAttr", p, null, false, doubleChance);
+      applyAbAttrs("DoubleBattleChanceAbAttr", { pokemon: p, chance: doubleChance });
     }
     return Math.max(doubleChance.value, 1);
   }
@@ -1461,7 +1461,7 @@ export default class BattleScene extends SceneBase {
         for (const pokemon of this.getPlayerParty()) {
           pokemon.resetBattleAndWaveData();
           pokemon.resetTera();
-          applyPostBattleInitAbAttrs("PostBattleInitAbAttr", pokemon);
+          applyAbAttrs("PostBattleInitAbAttr", { pokemon });
           if (
             pokemon.hasSpecies(SpeciesId.TERAPAGOS) ||
             (this.gameMode.isClassic && this.currentBattle.waveIndex > 180 && this.currentBattle.waveIndex <= 190)
@@ -2743,7 +2743,7 @@ export default class BattleScene extends SceneBase {
     const cancelled = new BooleanHolder(false);
 
     if (source && source.isPlayer() !== target.isPlayer()) {
-      applyAbAttrs("BlockItemTheftAbAttr", source, cancelled);
+      applyAbAttrs("BlockItemTheftAbAttr", { pokemon: source, cancelled });
     }
 
     if (cancelled.value) {
@@ -2783,13 +2783,13 @@ export default class BattleScene extends SceneBase {
           if (target.isPlayer()) {
             this.addModifier(newItemModifier, ignoreUpdate, playSound, false, instant);
             if (source && itemLost) {
-              applyPostItemLostAbAttrs("PostItemLostAbAttr", source, false);
+              applyAbAttrs("PostItemLostAbAttr", { pokemon: source });
             }
             return true;
           }
           this.addEnemyModifier(newItemModifier, ignoreUpdate, instant);
           if (source && itemLost) {
-            applyPostItemLostAbAttrs("PostItemLostAbAttr", source, false);
+            applyAbAttrs("PostItemLostAbAttr", { pokemon: source });
           }
           return true;
         }
@@ -2812,7 +2812,7 @@ export default class BattleScene extends SceneBase {
     const cancelled = new BooleanHolder(false);
 
     if (source && source.isPlayer() !== target.isPlayer()) {
-      applyAbAttrs("BlockItemTheftAbAttr", source, cancelled);
+      applyAbAttrs("BlockItemTheftAbAttr", { pokemon: source, cancelled });
     }
 
     if (cancelled.value) {

src/data/abilities/apply-ab-attrs.ts

@@ -1,63 +1,14 @@
-import type { AbAttrApplyFunc, AbAttrMap, AbAttrString, AbAttrSuccessFunc } from "#app/@types/ability-types";
-import type Pokemon from "#app/field/pokemon";
+import type { AbAttrParamMap } from "#app/@types/ability-types";
+import type { AbAttrBaseParams, AbAttrString, CallableAbAttrString } from "#app/@types/ability-types";
 import { globalScene } from "#app/global-scene";
-import type { BooleanHolder, NumberHolder } from "#app/utils/common";
-import type { BattlerIndex } from "#enums/battler-index";
-import type { HitResult } from "#enums/hit-result";
-import type { BattleStat, Stat } from "#enums/stat";
-import type { StatusEffect } from "#enums/status-effect";
-import type { WeatherType } from "#enums/weather-type";
-import type { BattlerTag } from "../battler-tags";
-import type Move from "../moves/move";
-import type { PokemonMove } from "../moves/pokemon-move";
-import type { TerrainType } from "../terrain";
-import type { Weather } from "../weather";
-import type {
-  PostBattleInitAbAttr,
-  PreDefendAbAttr,
-  PostDefendAbAttr,
-  PostMoveUsedAbAttr,
-  StatMultiplierAbAttr,
-  AllyStatMultiplierAbAttr,
-  PostSetStatusAbAttr,
-  PostDamageAbAttr,
-  FieldMultiplyStatAbAttr,
-  PreAttackAbAttr,
-  ExecutedMoveAbAttr,
-  PostAttackAbAttr,
-  PostKnockOutAbAttr,
-  PostVictoryAbAttr,
-  PostSummonAbAttr,
-  PreSummonAbAttr,
-  PreSwitchOutAbAttr,
-  PreLeaveFieldAbAttr,
-  PreStatStageChangeAbAttr,
-  PostStatStageChangeAbAttr,
-  PreSetStatusAbAttr,
-  PreApplyBattlerTagAbAttr,
-  PreWeatherEffectAbAttr,
-  PreWeatherDamageAbAttr,
-  PostTurnAbAttr,
-  PostWeatherChangeAbAttr,
-  PostWeatherLapseAbAttr,
-  PostTerrainChangeAbAttr,
-  CheckTrappedAbAttr,
-  PostBattleAbAttr,
-  PostFaintAbAttr,
-  PostItemLostAbAttr,
-} from "./ability";
 
 function applySingleAbAttrs<T extends AbAttrString>(
-  pokemon: Pokemon,
-  passive: boolean,
   attrType: T,
-  applyFunc: AbAttrApplyFunc<AbAttrMap[T]>,
-  successFunc: AbAttrSuccessFunc<AbAttrMap[T]>,
-  args: any[],
+  params: AbAttrParamMap[T],
   gainedMidTurn = false,
-  simulated = false,
   messages: string[] = [],
 ) {
+  const { simulated = false, passive = false, pokemon } = params;
   if (!pokemon?.canApplyAbility(passive) || (passive && pokemon.getPassiveAbility().id === pokemon.getAbility().id)) {
     return;
   }
@@ -72,10 +23,15 @@ function applySingleAbAttrs<T extends AbAttrString>(
     return;
   }
 
+  // typescript assert
   for (const attr of ability.getAttrs(attrType)) {
     const condition = attr.getCondition();
     let abShown = false;
-    if ((condition && !condition(pokemon)) || !successFunc(attr, passive)) {
+    if (
+      (condition && !condition(pokemon)) ||
+      // @ts-ignore: typescript can't unify the type of params with the generic type that was passed
+      !attr.canApply(params)
+    ) {
       continue;
     }
 
@@ -85,7 +41,8 @@ function applySingleAbAttrs<T extends AbAttrString>(
       globalScene.phaseManager.queueAbilityDisplay(pokemon, passive, true);
       abShown = true;
     }
-    const message = attr.getTriggerMessage(pokemon, ability.name, args);
+    // @ts-expect-error - typescript can't unify the type of params with the generic type that was passed
+    const message = attr.getTriggerMessage(params, ability.name);
     if (message) {
       if (!simulated) {
         globalScene.phaseManager.queueMessage(message);
@@ -93,7 +50,8 @@ function applySingleAbAttrs<T extends AbAttrString>(
       messages.push(message);
     }
 
-    applyFunc(attr, passive);
+    // @ts-ignore: typescript can't unify the type of params with the generic type that was passed
+    attr.apply(params);
 
     if (abShown) {
       globalScene.phaseManager.queueAbilityDisplay(pokemon, passive, false);
@@ -107,726 +65,60 @@ function applySingleAbAttrs<T extends AbAttrString>(
   }
 }
 
-function applyAbAttrsInternal<T extends AbAttrString>(
+function applyAbAttrsInternal<T extends CallableAbAttrString>(
   attrType: T,
-  pokemon: Pokemon | null,
-  applyFunc: AbAttrApplyFunc<AbAttrMap[T]>,
-  successFunc: AbAttrSuccessFunc<AbAttrMap[T]>,
-  args: any[],
-  simulated = false,
+  params: AbAttrParamMap[T],
   messages: string[] = [],
   gainedMidTurn = false,
 ) {
+  // If the pokemon is not defined, no ability attributes to be applied.
+  // TODO: Evaluate whether this check is even necessary anymore
+  if (!params.pokemon) {
+    return;
+  }
+  if (params.passive !== undefined) {
+    applySingleAbAttrs(attrType, params, gainedMidTurn, messages);
+    return;
+  }
   for (const passive of [false, true]) {
-    if (pokemon) {
-      applySingleAbAttrs(pokemon, passive, attrType, applyFunc, successFunc, args, gainedMidTurn, simulated, messages);
-      globalScene.phaseManager.clearPhaseQueueSplice();
-    }
+    params.passive = passive;
+    applySingleAbAttrs(attrType, params, gainedMidTurn, messages);
+    globalScene.phaseManager.clearPhaseQueueSplice();
+    // We need to restore passive to its original state in case it was undefined earlier
+    // this is necessary in case this method is called with an object that is reused.
+    params.passive = undefined;
   }
 }
 
-export function applyAbAttrs<T extends AbAttrString>(
+/**
+ * @param attrType - The type of the ability attribute to apply. (note: may not be any attribute that extends PostSummonAbAttr)
+ * @param params - The parameters to pass to the ability attribute's apply method
+ * @param messages - An optional array to which ability trigger messges will be added
+ */
+export function applyAbAttrs<T extends CallableAbAttrString>(
   attrType: T,
-  pokemon: Pokemon,
-  cancelled: BooleanHolder | null,
-  simulated = false,
-  ...args: any[]
+  params: AbAttrParamMap[T],
+  messages?: string[],
 ): void {
-  applyAbAttrsInternal<T>(
-    attrType,
-    pokemon,
-    // @ts-expect-error: TODO: fix the error on `cancelled`
-    (attr, passive) => attr.apply(pokemon, passive, simulated, cancelled, args),
-    (attr, passive) => attr.canApply(pokemon, passive, simulated, args),
-    args,
-    simulated,
-  );
+  applyAbAttrsInternal(attrType, params, messages);
 }
 
 // TODO: Improve the type signatures of the following methods / refactor the apply methods
 
-export function applyPostBattleInitAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostBattleInitAbAttr ? K : never,
-  pokemon: Pokemon,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) => (attr as PostBattleInitAbAttr).applyPostBattleInit(pokemon, passive, simulated, args),
-    (attr, passive) => (attr as PostBattleInitAbAttr).canApplyPostBattleInit(pokemon, passive, simulated, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPreDefendAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PreDefendAbAttr ? K : never,
-  pokemon: Pokemon,
-  attacker: Pokemon,
-  move: Move | null,
-  cancelled: BooleanHolder | null,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as PreDefendAbAttr).applyPreDefend(pokemon, passive, simulated, attacker, move, cancelled, args),
-    (attr, passive) =>
-      (attr as PreDefendAbAttr).canApplyPreDefend(pokemon, passive, simulated, attacker, move, cancelled, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostDefendAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostDefendAbAttr ? K : never,
-  pokemon: Pokemon,
-  attacker: Pokemon,
-  move: Move,
-  hitResult: HitResult | null,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as PostDefendAbAttr).applyPostDefend(pokemon, passive, simulated, attacker, move, hitResult, args),
-    (attr, passive) =>
-      (attr as PostDefendAbAttr).canApplyPostDefend(pokemon, passive, simulated, attacker, move, hitResult, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostMoveUsedAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostMoveUsedAbAttr ? K : never,
-  pokemon: Pokemon,
-  move: PokemonMove,
-  source: Pokemon,
-  targets: BattlerIndex[],
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, _passive) => (attr as PostMoveUsedAbAttr).applyPostMoveUsed(pokemon, move, source, targets, simulated, args),
-    (attr, _passive) =>
-      (attr as PostMoveUsedAbAttr).canApplyPostMoveUsed(pokemon, move, source, targets, simulated, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyStatMultiplierAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends StatMultiplierAbAttr ? K : never,
-  pokemon: Pokemon,
-  stat: BattleStat,
-  statValue: NumberHolder,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as StatMultiplierAbAttr).applyStatStage(pokemon, passive, simulated, stat, statValue, args),
-    (attr, passive) =>
-      (attr as StatMultiplierAbAttr).canApplyStatStage(pokemon, passive, simulated, stat, statValue, args),
-    args,
-  );
-}
-
-/**
- * Applies an ally's Stat multiplier attribute
- * @param attrType - {@linkcode AllyStatMultiplierAbAttr} should always be AllyStatMultiplierAbAttr for the time being
- * @param pokemon - The {@linkcode Pokemon} with the ability
- * @param stat - The type of the checked {@linkcode Stat}
- * @param statValue - {@linkcode NumberHolder} containing the value of the checked stat
- * @param checkedPokemon - The {@linkcode Pokemon} with the checked stat
- * @param ignoreAbility - Whether or not the ability should be ignored by the pokemon or its move.
- * @param args - unused
- */
-export function applyAllyStatMultiplierAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends AllyStatMultiplierAbAttr ? K : never,
-  pokemon: Pokemon,
-  stat: BattleStat,
-  statValue: NumberHolder,
-  simulated = false,
-  checkedPokemon: Pokemon,
-  ignoreAbility: boolean,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as AllyStatMultiplierAbAttr).applyAllyStat(
-        pokemon,
-        passive,
-        simulated,
-        stat,
-        statValue,
-        checkedPokemon,
-        ignoreAbility,
-        args,
-      ),
-    (attr, passive) =>
-      (attr as AllyStatMultiplierAbAttr).canApplyAllyStat(
-        pokemon,
-        passive,
-        simulated,
-        stat,
-        statValue,
-        checkedPokemon,
-        ignoreAbility,
-        args,
-      ),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostSetStatusAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostSetStatusAbAttr ? K : never,
-  pokemon: Pokemon,
-  effect: StatusEffect,
-  sourcePokemon?: Pokemon | null,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as PostSetStatusAbAttr).applyPostSetStatus(pokemon, sourcePokemon, passive, effect, simulated, args),
-    (attr, passive) =>
-      (attr as PostSetStatusAbAttr).canApplyPostSetStatus(pokemon, sourcePokemon, passive, effect, simulated, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostDamageAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostDamageAbAttr ? K : never,
-  pokemon: Pokemon,
-  damage: number,
-  _passive: boolean,
-  simulated = false,
-  args: any[],
-  source?: Pokemon,
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) => (attr as PostDamageAbAttr).applyPostDamage(pokemon, damage, passive, simulated, args, source),
-    (attr, passive) => (attr as PostDamageAbAttr).canApplyPostDamage(pokemon, damage, passive, simulated, args, source),
-    args,
-  );
-}
-/**
- * Applies a field Stat multiplier attribute
- * @param attrType {@linkcode FieldMultiplyStatAbAttr} should always be FieldMultiplyBattleStatAbAttr for the time being
- * @param pokemon {@linkcode Pokemon} the Pokemon applying this ability
- * @param stat {@linkcode Stat} the type of the checked stat
- * @param statValue {@linkcode NumberHolder} the value of the checked stat
- * @param checkedPokemon {@linkcode Pokemon} the Pokemon with the checked stat
- * @param hasApplied {@linkcode BooleanHolder} whether or not a FieldMultiplyBattleStatAbAttr has already affected this stat
- * @param args unused
- */
-
-export function applyFieldStatMultiplierAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends FieldMultiplyStatAbAttr ? K : never,
-  pokemon: Pokemon,
-  stat: Stat,
-  statValue: NumberHolder,
-  checkedPokemon: Pokemon,
-  hasApplied: BooleanHolder,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as FieldMultiplyStatAbAttr).applyFieldStat(
-        pokemon,
-        passive,
-        simulated,
-        stat,
-        statValue,
-        checkedPokemon,
-        hasApplied,
-        args,
-      ),
-    (attr, passive) =>
-      (attr as FieldMultiplyStatAbAttr).canApplyFieldStat(
-        pokemon,
-        passive,
-        simulated,
-        stat,
-        statValue,
-        checkedPokemon,
-        hasApplied,
-        args,
-      ),
-    args,
-  );
-}
-
-export function applyPreAttackAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PreAttackAbAttr ? K : never,
-  pokemon: Pokemon,
-  defender: Pokemon | null,
-  move: Move,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) => (attr as PreAttackAbAttr).applyPreAttack(pokemon, passive, simulated, defender, move, args),
-    (attr, passive) => (attr as PreAttackAbAttr).canApplyPreAttack(pokemon, passive, simulated, defender, move, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyExecutedMoveAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends ExecutedMoveAbAttr ? K : never,
-  pokemon: Pokemon,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    attr => (attr as ExecutedMoveAbAttr).applyExecutedMove(pokemon, simulated),
-    attr => (attr as ExecutedMoveAbAttr).canApplyExecutedMove(pokemon, simulated),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostAttackAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostAttackAbAttr ? K : never,
-  pokemon: Pokemon,
-  defender: Pokemon,
-  move: Move,
-  hitResult: HitResult | null,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as PostAttackAbAttr).applyPostAttack(pokemon, passive, simulated, defender, move, hitResult, args),
-    (attr, passive) =>
-      (attr as PostAttackAbAttr).canApplyPostAttack(pokemon, passive, simulated, defender, move, hitResult, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostKnockOutAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostKnockOutAbAttr ? K : never,
-  pokemon: Pokemon,
-  knockedOut: Pokemon,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) => (attr as PostKnockOutAbAttr).applyPostKnockOut(pokemon, passive, simulated, knockedOut, args),
-    (attr, passive) => (attr as PostKnockOutAbAttr).canApplyPostKnockOut(pokemon, passive, simulated, knockedOut, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostVictoryAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostVictoryAbAttr ? K : never,
-  pokemon: Pokemon,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) => (attr as PostVictoryAbAttr).applyPostVictory(pokemon, passive, simulated, args),
-    (attr, passive) => (attr as PostVictoryAbAttr).canApplyPostVictory(pokemon, passive, simulated, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostSummonAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostSummonAbAttr ? K : never,
-  pokemon: Pokemon,
-  passive = false,
-  simulated = false,
-  ...args: any[]
-): void {
-  applySingleAbAttrs(
-    pokemon,
-    passive,
-    attrType,
-    (attr, passive) => (attr as PostSummonAbAttr).applyPostSummon(pokemon, passive, simulated, args),
-    (attr, passive) => (attr as PostSummonAbAttr).canApplyPostSummon(pokemon, passive, simulated, args),
-    args,
-    false,
-    simulated,
-  );
-}
-
-export function applyPreSummonAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PreSummonAbAttr ? K : never,
-  pokemon: Pokemon,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) => (attr as PreSummonAbAttr).applyPreSummon(pokemon, passive, args),
-    (attr, passive) => (attr as PreSummonAbAttr).canApplyPreSummon(pokemon, passive, args),
-    args,
-  );
-}
-
-export function applyPreSwitchOutAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PreSwitchOutAbAttr ? K : never,
-  pokemon: Pokemon,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) => (attr as PreSwitchOutAbAttr).applyPreSwitchOut(pokemon, passive, simulated, args),
-    (attr, passive) => (attr as PreSwitchOutAbAttr).canApplyPreSwitchOut(pokemon, passive, simulated, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPreLeaveFieldAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PreLeaveFieldAbAttr ? K : never,
-  pokemon: Pokemon,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) => (attr as PreLeaveFieldAbAttr).applyPreLeaveField(pokemon, passive, simulated, args),
-    (attr, passive) => (attr as PreLeaveFieldAbAttr).canApplyPreLeaveField(pokemon, passive, simulated, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPreStatStageChangeAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PreStatStageChangeAbAttr ? K : never,
-  pokemon: Pokemon | null,
-  stat: BattleStat,
-  cancelled: BooleanHolder,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as PreStatStageChangeAbAttr).applyPreStatStageChange(pokemon, passive, simulated, stat, cancelled, args),
-    (attr, passive) =>
-      (attr as PreStatStageChangeAbAttr).canApplyPreStatStageChange(pokemon, passive, simulated, stat, cancelled, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostStatStageChangeAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostStatStageChangeAbAttr ? K : never,
-  pokemon: Pokemon,
-  stats: BattleStat[],
-  stages: number,
-  selfTarget: boolean,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, _passive) =>
-      (attr as PostStatStageChangeAbAttr).applyPostStatStageChange(pokemon, simulated, stats, stages, selfTarget, args),
-    (attr, _passive) =>
-      (attr as PostStatStageChangeAbAttr).canApplyPostStatStageChange(
-        pokemon,
-        simulated,
-        stats,
-        stages,
-        selfTarget,
-        args,
-      ),
-    args,
-    simulated,
-  );
-}
-
-export function applyPreSetStatusAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PreSetStatusAbAttr ? K : never,
-  pokemon: Pokemon,
-  effect: StatusEffect | undefined,
-  cancelled: BooleanHolder,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as PreSetStatusAbAttr).applyPreSetStatus(pokemon, passive, simulated, effect, cancelled, args),
-    (attr, passive) =>
-      (attr as PreSetStatusAbAttr).canApplyPreSetStatus(pokemon, passive, simulated, effect, cancelled, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPreApplyBattlerTagAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PreApplyBattlerTagAbAttr ? K : never,
-  pokemon: Pokemon,
-  tag: BattlerTag,
-  cancelled: BooleanHolder,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as PreApplyBattlerTagAbAttr).applyPreApplyBattlerTag(pokemon, passive, simulated, tag, cancelled, args),
-    (attr, passive) =>
-      (attr as PreApplyBattlerTagAbAttr).canApplyPreApplyBattlerTag(pokemon, passive, simulated, tag, cancelled, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPreWeatherEffectAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PreWeatherEffectAbAttr ? K : never,
-  pokemon: Pokemon,
-  weather: Weather | null,
-  cancelled: BooleanHolder,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as PreWeatherDamageAbAttr).applyPreWeatherEffect(pokemon, passive, simulated, weather, cancelled, args),
-    (attr, passive) =>
-      (attr as PreWeatherDamageAbAttr).canApplyPreWeatherEffect(pokemon, passive, simulated, weather, cancelled, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostTurnAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostTurnAbAttr ? K : never,
-  pokemon: Pokemon,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) => (attr as PostTurnAbAttr).applyPostTurn(pokemon, passive, simulated, args),
-    (attr, passive) => (attr as PostTurnAbAttr).canApplyPostTurn(pokemon, passive, simulated, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostWeatherChangeAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostWeatherChangeAbAttr ? K : never,
-  pokemon: Pokemon,
-  weather: WeatherType,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as PostWeatherChangeAbAttr).applyPostWeatherChange(pokemon, passive, simulated, weather, args),
-    (attr, passive) =>
-      (attr as PostWeatherChangeAbAttr).canApplyPostWeatherChange(pokemon, passive, simulated, weather, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostWeatherLapseAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostWeatherLapseAbAttr ? K : never,
-  pokemon: Pokemon,
-  weather: Weather | null,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as PostWeatherLapseAbAttr).applyPostWeatherLapse(pokemon, passive, simulated, weather, args),
-    (attr, passive) =>
-      (attr as PostWeatherLapseAbAttr).canApplyPostWeatherLapse(pokemon, passive, simulated, weather, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostTerrainChangeAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostTerrainChangeAbAttr ? K : never,
-  pokemon: Pokemon,
-  terrain: TerrainType,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as PostTerrainChangeAbAttr).applyPostTerrainChange(pokemon, passive, simulated, terrain, args),
-    (attr, passive) =>
-      (attr as PostTerrainChangeAbAttr).canApplyPostTerrainChange(pokemon, passive, simulated, terrain, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyCheckTrappedAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends CheckTrappedAbAttr ? K : never,
-  pokemon: Pokemon,
-  trapped: BooleanHolder,
-  otherPokemon: Pokemon,
-  messages: string[],
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as CheckTrappedAbAttr).applyCheckTrapped(pokemon, passive, simulated, trapped, otherPokemon, args),
-    (attr, passive) =>
-      (attr as CheckTrappedAbAttr).canApplyCheckTrapped(pokemon, passive, simulated, trapped, otherPokemon, args),
-    args,
-    simulated,
-    messages,
-  );
-}
-
-export function applyPostBattleAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostBattleAbAttr ? K : never,
-  pokemon: Pokemon,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) => (attr as PostBattleAbAttr).applyPostBattle(pokemon, passive, simulated, args),
-    (attr, passive) => (attr as PostBattleAbAttr).canApplyPostBattle(pokemon, passive, simulated, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostFaintAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostFaintAbAttr ? K : never,
-  pokemon: Pokemon,
-  attacker?: Pokemon,
-  move?: Move,
-  hitResult?: HitResult,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, passive) =>
-      (attr as PostFaintAbAttr).applyPostFaint(pokemon, passive, simulated, attacker, move, hitResult, args),
-    (attr, passive) =>
-      (attr as PostFaintAbAttr).canApplyPostFaint(pokemon, passive, simulated, attacker, move, hitResult, args),
-    args,
-    simulated,
-  );
-}
-
-export function applyPostItemLostAbAttrs<K extends AbAttrString>(
-  attrType: AbAttrMap[K] extends PostItemLostAbAttr ? K : never,
-  pokemon: Pokemon,
-  simulated = false,
-  ...args: any[]
-): void {
-  applyAbAttrsInternal(
-    attrType,
-    pokemon,
-    (attr, _passive) => (attr as PostItemLostAbAttr).applyPostItemLost(pokemon, simulated, args),
-    (attr, _passive) => (attr as PostItemLostAbAttr).canApplyPostItemLost(pokemon, simulated, args),
-    args,
-  );
-}
-
 /**
  * Applies abilities when they become active mid-turn (ability switch)
  *
  * Ignores passives as they don't change and shouldn't be reapplied when main abilities change
  */
-export function applyOnGainAbAttrs(pokemon: Pokemon, passive = false, simulated = false, ...args: any[]): void {
-  applySingleAbAttrs(
-    pokemon,
-    passive,
-    "PostSummonAbAttr",
-    (attr, passive) => attr.applyPostSummon(pokemon, passive, simulated, args),
-    (attr, passive) => attr.canApplyPostSummon(pokemon, passive, simulated, args),
-    args,
-    true,
-    simulated,
-  );
+export function applyOnGainAbAttrs(params: AbAttrBaseParams): void {
+  applySingleAbAttrs("PostSummonAbAttr", params, true);
 }
+
 /**
  * Applies ability attributes which activate when the ability is lost or suppressed (i.e. primal weather)
  */
-export function applyOnLoseAbAttrs(pokemon: Pokemon, passive = false, simulated = false, ...args: any[]): void {
-  applySingleAbAttrs(
-    pokemon,
-    passive,
-    "PreLeaveFieldAbAttr",
-    (attr, passive) => attr.applyPreLeaveField(pokemon, passive, simulated, [...args, true]),
-    (attr, passive) => attr.canApplyPreLeaveField(pokemon, passive, simulated, [...args, true]),
-    args,
-    true,
-    simulated,
-  );
+export function applyOnLoseAbAttrs(params: AbAttrBaseParams): void {
+  applySingleAbAttrs("PreLeaveFieldAbAttr", params, true);
 
-  applySingleAbAttrs(
-    pokemon,
-    passive,
-    "IllusionBreakAbAttr",
-    (attr, passive) => attr.apply(pokemon, passive, simulated, null, args),
-    (attr, passive) => attr.canApply(pokemon, passive, simulated, args),
-    args,
-    true,
-    simulated,
-  );
+  applySingleAbAttrs("IllusionBreakAbAttr", params, true);
 }

src/data/arena-tag.ts

@@ -137,7 +137,7 @@ export class MistTag extends ArenaTag {
     if (attacker) {
       const bypassed = new BooleanHolder(false);
       // TODO: Allow this to be simulated
-      applyAbAttrs("InfiltratorAbAttr", attacker, null, false, bypassed);
+      applyAbAttrs("InfiltratorAbAttr", { pokemon: attacker, simulated: false, bypassed });
       if (bypassed.value) {
         return false;
       }
@@ -202,7 +202,7 @@ export class WeakenMoveScreenTag extends ArenaTag {
   ): boolean {
     if (this.weakenedCategories.includes(moveCategory)) {
       const bypassed = new BooleanHolder(false);
-      applyAbAttrs("InfiltratorAbAttr", attacker, null, false, bypassed);
+      applyAbAttrs("InfiltratorAbAttr", { pokemon: attacker, bypassed });
       if (bypassed.value) {
         return false;
       }
@@ -758,7 +758,7 @@ class SpikesTag extends ArenaTrapTag {
     }
 
     const cancelled = new BooleanHolder(false);
-    applyAbAttrs("BlockNonDirectDamageAbAttr", pokemon, cancelled);
+    applyAbAttrs("BlockNonDirectDamageAbAttr", { pokemon, cancelled });
     if (simulated || cancelled.value) {
       return !cancelled.value;
     }
@@ -946,7 +946,7 @@ class StealthRockTag extends ArenaTrapTag {
 
   override activateTrap(pokemon: Pokemon, simulated: boolean): boolean {
     const cancelled = new BooleanHolder(false);
-    applyAbAttrs("BlockNonDirectDamageAbAttr", pokemon, cancelled);
+    applyAbAttrs("BlockNonDirectDamageAbAttr", { pokemon, cancelled });
     if (cancelled.value) {
       return false;
     }
@@ -1003,7 +1003,12 @@ class StickyWebTag extends ArenaTrapTag {
   override activateTrap(pokemon: Pokemon, simulated: boolean): boolean {
     if (pokemon.isGrounded()) {
       const cancelled = new BooleanHolder(false);
-      applyAbAttrs("ProtectStatAbAttr", pokemon, cancelled);
+      applyAbAttrs("ProtectStatAbAttr", {
+        pokemon,
+        cancelled,
+        stat: Stat.SPD,
+        stages: -1,
+      });
 
       if (simulated) {
         return !cancelled.value;
@@ -1416,7 +1421,9 @@ export class SuppressAbilitiesTag extends ArenaTag {
 
       for (const fieldPokemon of globalScene.getField(true)) {
         if (fieldPokemon && fieldPokemon.id !== pokemon.id) {
-          [true, false].forEach(passive => applyOnLoseAbAttrs(fieldPokemon, passive));
+          // TODO: investigate whether we can just remove the foreach and call `applyAbAttrs` directly, providing
+          // the appropriate attributes (preLEaveField and IllusionBreak)
+          [true, false].forEach(passive => applyOnLoseAbAttrs({ pokemon: fieldPokemon, passive }));
         }
       }
     }
@@ -1438,7 +1445,10 @@ export class SuppressAbilitiesTag extends ArenaTag {
       const setter = globalScene
         .getField()
         .filter(p => p?.hasAbilityWithAttr("PreLeaveFieldRemoveSuppressAbilitiesSourceAbAttr", false))[0];
-      applyOnGainAbAttrs(setter, setter.getAbility().hasAttr("PreLeaveFieldRemoveSuppressAbilitiesSourceAbAttr"));
+      applyOnGainAbAttrs({
+        pokemon: setter,
+        passive: setter.getAbility().hasAttr("PreLeaveFieldRemoveSuppressAbilitiesSourceAbAttr"),
+      });
     }
   }
 
@@ -1451,7 +1461,7 @@ export class SuppressAbilitiesTag extends ArenaTag {
     for (const pokemon of globalScene.getField(true)) {
       // There is only one pokemon with this attr on the field on removal, so its abilities are already active
       if (pokemon && !pokemon.hasAbilityWithAttr("PreLeaveFieldRemoveSuppressAbilitiesSourceAbAttr", false)) {
-        [true, false].forEach(passive => applyOnGainAbAttrs(pokemon, passive));
+        [true, false].forEach(passive => applyOnGainAbAttrs({ pokemon, passive }));
       }
     }
   }

src/data/battler-tags.ts

@@ -621,7 +621,7 @@ export class FlinchedTag extends BattlerTag {
           pokemonNameWithAffix: getPokemonNameWithAffix(pokemon),
         }),
       );
-      applyAbAttrs("FlinchEffectAbAttr", pokemon, null);
+      applyAbAttrs("FlinchEffectAbAttr", { pokemon });
       return true;
     }
 
@@ -916,7 +916,7 @@ export class SeedTag extends BattlerTag {
       const source = pokemon.getOpponents().find(o => o.getBattlerIndex() === this.sourceIndex);
       if (source) {
         const cancelled = new BooleanHolder(false);
-        applyAbAttrs("BlockNonDirectDamageAbAttr", pokemon, cancelled);
+        applyAbAttrs("BlockNonDirectDamageAbAttr", { pokemon, cancelled });
 
         if (!cancelled.value) {
           globalScene.phaseManager.unshiftNew(
@@ -1006,7 +1006,7 @@ export class PowderTag extends BattlerTag {
     globalScene.phaseManager.unshiftNew("CommonAnimPhase", idx, idx, CommonAnim.POWDER);
 
     const cancelDamage = new BooleanHolder(false);
-    applyAbAttrs("BlockNonDirectDamageAbAttr", pokemon, cancelDamage);
+    applyAbAttrs("BlockNonDirectDamageAbAttr", { pokemon, cancelled: cancelDamage });
     if (!cancelDamage.value) {
       pokemon.damageAndUpdate(Math.floor(pokemon.getMaxHp() / 4), { result: HitResult.INDIRECT });
     }
@@ -1056,7 +1056,7 @@ export class NightmareTag extends BattlerTag {
       phaseManager.unshiftNew("CommonAnimPhase", pokemon.getBattlerIndex(), undefined, CommonAnim.CURSE); // TODO: Update animation type
 
       const cancelled = new BooleanHolder(false);
-      applyAbAttrs("BlockNonDirectDamageAbAttr", pokemon, cancelled);
+      applyAbAttrs("BlockNonDirectDamageAbAttr", { pokemon, cancelled });
 
       if (!cancelled.value) {
         pokemon.damageAndUpdate(toDmgValue(pokemon.getMaxHp() / 4), { result: HitResult.INDIRECT });
@@ -1409,7 +1409,7 @@ export abstract class DamagingTrapTag extends TrappedTag {
       phaseManager.unshiftNew("CommonAnimPhase", pokemon.getBattlerIndex(), undefined, this.commonAnim);
 
       const cancelled = new BooleanHolder(false);
-      applyAbAttrs("BlockNonDirectDamageAbAttr", pokemon, cancelled);
+      applyAbAttrs("BlockNonDirectDamageAbAttr", { pokemon, cancelled });
 
       if (!cancelled.value) {
         pokemon.damageAndUpdate(toDmgValue(pokemon.getMaxHp() / 8), { result: HitResult.INDIRECT });
@@ -1642,7 +1642,7 @@ export class ContactDamageProtectedTag extends ContactProtectedTag {
    */
   override onContact(attacker: Pokemon, user: Pokemon): void {
     const cancelled = new BooleanHolder(false);
-    applyAbAttrs("BlockNonDirectDamageAbAttr", user, cancelled);
+    applyAbAttrs("BlockNonDirectDamageAbAttr", { pokemon: user, cancelled });
     if (!cancelled.value) {
       attacker.damageAndUpdate(toDmgValue(attacker.getMaxHp() * (1 / this.damageRatio)), {
         result: HitResult.INDIRECT,
@@ -2243,7 +2243,7 @@ export class SaltCuredTag extends BattlerTag {
       );
 
       const cancelled = new BooleanHolder(false);
-      applyAbAttrs("BlockNonDirectDamageAbAttr", pokemon, cancelled);
+      applyAbAttrs("BlockNonDirectDamageAbAttr", { pokemon, cancelled });
 
       if (!cancelled.value) {
         const pokemonSteelOrWater = pokemon.isOfType(PokemonType.STEEL) || pokemon.isOfType(PokemonType.WATER);
@@ -2297,7 +2297,7 @@ export class CursedTag extends BattlerTag {
       );
 
       const cancelled = new BooleanHolder(false);
-      applyAbAttrs("BlockNonDirectDamageAbAttr", pokemon, cancelled);
+      applyAbAttrs("BlockNonDirectDamageAbAttr", { pokemon, cancelled });
 
       if (!cancelled.value) {
         pokemon.damageAndUpdate(toDmgValue(pokemon.getMaxHp() / 4), { result: HitResult.INDIRECT });
@@ -2632,7 +2632,7 @@ export class GulpMissileTag extends BattlerTag {
       }
 
       const cancelled = new BooleanHolder(false);
-      applyAbAttrs("BlockNonDirectDamageAbAttr", attacker, cancelled);
+      applyAbAttrs("BlockNonDirectDamageAbAttr", { pokemon: attacker, cancelled });
 
       if (!cancelled.value) {
         attacker.damageAndUpdate(Math.max(1, Math.floor(attacker.getMaxHp() / 4)), { result: HitResult.INDIRECT });
@@ -3021,14 +3021,7 @@ export class MysteryEncounterPostSummonTag extends BattlerTag {
     const ret = super.lapse(pokemon, lapseType);
 
     if (lapseType === BattlerTagLapseType.CUSTOM) {
-      const cancelled = new BooleanHolder(false);
-      applyAbAttrs("ProtectStatAbAttr", pokemon, cancelled);
-      applyAbAttrs("ConditionalUserFieldProtectStatAbAttr", pokemon, cancelled, false, pokemon);
-      if (!cancelled.value) {
-        if (pokemon.mysteryEncounterBattleEffects) {
-          pokemon.mysteryEncounterBattleEffects(pokemon);
-        }
-      }
+      pokemon.mysteryEncounterBattleEffects?.(pokemon);
     }
 
     return ret;

src/data/berry.ts

@@ -35,28 +35,28 @@ export function getBerryPredicate(berryType: BerryType): BerryPredicate {
     case BerryType.APICOT:
     case BerryType.SALAC:
       return (pokemon: Pokemon) => {
-        const threshold = new NumberHolder(0.25);
+        const hpRatioReq = new NumberHolder(0.25);
         // Offset BerryType such that LIECHI -> Stat.ATK = 1, GANLON -> Stat.DEF = 2, so on and so forth
         const stat: BattleStat = berryType - BerryType.ENIGMA;
-        applyAbAttrs("ReduceBerryUseThresholdAbAttr", pokemon, null, false, threshold);
-        return pokemon.getHpRatio() < threshold.value && pokemon.getStatStage(stat) < 6;
+        applyAbAttrs("ReduceBerryUseThresholdAbAttr", { pokemon, hpRatioReq });
+        return pokemon.getHpRatio() < hpRatioReq.value && pokemon.getStatStage(stat) < 6;
       };
     case BerryType.LANSAT:
       return (pokemon: Pokemon) => {
-        const threshold = new NumberHolder(0.25);
-        applyAbAttrs("ReduceBerryUseThresholdAbAttr", pokemon, null, false, threshold);
+        const hpRatioReq = new NumberHolder(0.25);
+        applyAbAttrs("ReduceBerryUseThresholdAbAttr", { pokemon, hpRatioReq });
         return pokemon.getHpRatio() < 0.25 && !pokemon.getTag(BattlerTagType.CRIT_BOOST);
       };
     case BerryType.STARF:
       return (pokemon: Pokemon) => {
-        const threshold = new NumberHolder(0.25);
-        applyAbAttrs("ReduceBerryUseThresholdAbAttr", pokemon, null, false, threshold);
+        const hpRatioReq = new NumberHolder(0.25);
+        applyAbAttrs("ReduceBerryUseThresholdAbAttr", { pokemon, hpRatioReq });
         return pokemon.getHpRatio() < 0.25;
       };
     case BerryType.LEPPA:
       return (pokemon: Pokemon) => {
-        const threshold = new NumberHolder(0.25);
-        applyAbAttrs("ReduceBerryUseThresholdAbAttr", pokemon, null, false, threshold);
+        const hpRatioReq = new NumberHolder(0.25);
+        applyAbAttrs("ReduceBerryUseThresholdAbAttr", { pokemon, hpRatioReq });
         return !!pokemon.getMoveset().find(m => !m.getPpRatio());
       };
   }
@@ -72,7 +72,7 @@ export function getBerryEffectFunc(berryType: BerryType): BerryEffectFunc {
       case BerryType.ENIGMA:
         {
           const hpHealed = new NumberHolder(toDmgValue(consumer.getMaxHp() / 4));
-          applyAbAttrs("DoubleBerryEffectAbAttr", consumer, null, false, hpHealed);
+          applyAbAttrs("DoubleBerryEffectAbAttr", { pokemon: consumer, effectValue: hpHealed });
           globalScene.phaseManager.unshiftNew(
             "PokemonHealPhase",
             consumer.getBattlerIndex(),
@@ -105,7 +105,7 @@ export function getBerryEffectFunc(berryType: BerryType): BerryEffectFunc {
           // Offset BerryType such that LIECHI --> Stat.ATK = 1, GANLON --> Stat.DEF = 2, etc etc.
           const stat: BattleStat = berryType - BerryType.ENIGMA;
           const statStages = new NumberHolder(1);
-          applyAbAttrs("DoubleBerryEffectAbAttr", consumer, null, false, statStages);
+          applyAbAttrs("DoubleBerryEffectAbAttr", { pokemon: consumer, effectValue: statStages });
           globalScene.phaseManager.unshiftNew(
             "StatStageChangePhase",
             consumer.getBattlerIndex(),
@@ -126,7 +126,7 @@ export function getBerryEffectFunc(berryType: BerryType): BerryEffectFunc {
         {
           const randStat = randSeedInt(Stat.SPD, Stat.ATK);
           const stages = new NumberHolder(2);
-          applyAbAttrs("DoubleBerryEffectAbAttr", consumer, null, false, stages);
+          applyAbAttrs("DoubleBerryEffectAbAttr", { pokemon: consumer, effectValue: stages });
           globalScene.phaseManager.unshiftNew(
             "StatStageChangePhase",
             consumer.getBattlerIndex(),

src/data/moves/move.ts

@@ -33,11 +33,7 @@ import type { ArenaTrapTag } from "../arena-tag";
 import { WeakenMoveTypeTag } from "../arena-tag";
 import { ArenaTagSide } from "#enums/arena-tag-side";
 import {
-  applyAbAttrs,
-  applyPostAttackAbAttrs,
-  applyPostItemLostAbAttrs,
-  applyPreAttackAbAttrs,
-  applyPreDefendAbAttrs
+  applyAbAttrs
 } from "../abilities/apply-ab-attrs";
 import { allAbilities, allMoves } from "../data-lists";
 import {
@@ -92,6 +88,7 @@ import { isVirtual, MoveUseMode } from "#enums/move-use-mode";
 import { ChargingMove, MoveAttrMap, MoveAttrString, MoveKindString, MoveClassMap } from "#app/@types/move-types";
 import { applyMoveAttrs } from "./apply-attrs";
 import { frenzyMissFunc, getMoveTargets } from "./move-utils";
+import { AbAttrBaseParams, AbAttrParamsWithCancel, PreAttackModifyPowerAbAttrParams } from "../abilities/ability";
 
 type MoveConditionFunc = (user: Pokemon, target: Pokemon, move: Move) => boolean;
 export type UserMoveConditionFunc = (user: Pokemon, move: Move) => boolean;
@@ -343,7 +340,7 @@ export default abstract class Move implements Localizable {
 
     const bypassed = new BooleanHolder(false);
     // TODO: Allow this to be simulated
-    applyAbAttrs("InfiltratorAbAttr", user, null, false, bypassed);
+    applyAbAttrs("InfiltratorAbAttr", {pokemon: user, bypassed});
 
     return !bypassed.value
         && !this.hasFlag(MoveFlags.SOUND_BASED)
@@ -641,7 +638,7 @@ export default abstract class Move implements Localizable {
       case MoveFlags.IGNORE_ABILITIES:
         if (user.hasAbilityWithAttr("MoveAbilityBypassAbAttr")) {
           const abilityEffectsIgnored = new BooleanHolder(false);
-          applyAbAttrs("MoveAbilityBypassAbAttr", user, abilityEffectsIgnored, false, this);
+          applyAbAttrs("MoveAbilityBypassAbAttr", {pokemon: user, cancelled: abilityEffectsIgnored, move: this});
           if (abilityEffectsIgnored.value) {
             return true;
           }
@@ -758,7 +755,7 @@ export default abstract class Move implements Localizable {
     const moveAccuracy = new NumberHolder(this.accuracy);
 
     applyMoveAttrs("VariableAccuracyAttr", user, target, this, moveAccuracy);
-    applyPreDefendAbAttrs("WonderSkinAbAttr", target, user, this, { value: false }, simulated, moveAccuracy);
+    applyAbAttrs("WonderSkinAbAttr", {pokemon: target, opponent: user, move: this, simulated, accuracy: moveAccuracy});
 
     if (moveAccuracy.value === -1) {
       return moveAccuracy.value;
@@ -801,17 +798,25 @@ export default abstract class Move implements Localizable {
     const typeChangeMovePowerMultiplier = new NumberHolder(1);
     const typeChangeHolder = new NumberHolder(this.type);
 
-    applyPreAttackAbAttrs("MoveTypeChangeAbAttr", source, target, this, true, typeChangeHolder, typeChangeMovePowerMultiplier);
+    applyAbAttrs("MoveTypeChangeAbAttr", {pokemon: source, opponent: target, move: this, simulated: true, moveType: typeChangeHolder, power: typeChangeMovePowerMultiplier});
 
     const sourceTeraType = source.getTeraType();
     if (source.isTerastallized && sourceTeraType === this.type && power.value < 60 && this.priority <= 0 && !this.hasAttr("MultiHitAttr") && !globalScene.findModifier(m => m instanceof PokemonMultiHitModifier && m.pokemonId === source.id)) {
       power.value = 60;
     }
 
-    applyPreAttackAbAttrs("VariableMovePowerAbAttr", source, target, this, simulated, power);
+    const abAttrParams: PreAttackModifyPowerAbAttrParams = {
+      pokemon: source,
+      opponent: target,
+      simulated,
+      power,
+      move: this,
+    }
+
+    applyAbAttrs("VariableMovePowerAbAttr", abAttrParams);
     const ally = source.getAlly();
     if (!isNullOrUndefined(ally)) {
-      applyPreAttackAbAttrs("AllyMoveCategoryPowerBoostAbAttr", ally, target, this, simulated, power);
+      applyAbAttrs("AllyMoveCategoryPowerBoostAbAttr", {...abAttrParams, pokemon: ally});
     }
 
     const fieldAuras = new Set(
@@ -823,11 +828,12 @@ export default abstract class Move implements Localizable {
         .flat(),
     );
     for (const aura of fieldAuras) {
-      aura.applyPreAttack(source, null, simulated, target, this, [ power ]);
+      // TODO: Refactor the fieldAura attribute so that its apply method is not directly called
+      aura.apply({pokemon: source, simulated, opponent: target, move: this, power});
     }
 
     const alliedField: Pokemon[] = source.isPlayer() ? globalScene.getPlayerField() : globalScene.getEnemyField();
-    alliedField.forEach(p => applyPreAttackAbAttrs("UserFieldMoveTypePowerBoostAbAttr", p, target, this, simulated, power));
+    alliedField.forEach(p => applyAbAttrs("UserFieldMoveTypePowerBoostAbAttr", {pokemon: p, opponent: target, move: this, simulated, power}));
 
     power.value *= typeChangeMovePowerMultiplier.value;
 
@@ -854,7 +860,7 @@ export default abstract class Move implements Localizable {
     const priority = new NumberHolder(this.priority);
 
     applyMoveAttrs("IncrementMovePriorityAttr", user, null, this, priority);
-    applyAbAttrs("ChangeMovePriorityAbAttr", user, null, simulated, this, priority);
+    applyAbAttrs("ChangeMovePriorityAbAttr", {pokemon: user, simulated, move: this, priority});
 
     return priority.value;
   }
@@ -1306,7 +1312,7 @@ export class MoveEffectAttr extends MoveAttr {
   getMoveChance(user: Pokemon, target: Pokemon, move: Move, selfEffect?: Boolean, showAbility?: Boolean): number {
     const moveChance = new NumberHolder(this.effectChanceOverride ?? move.chance);
 
-    applyAbAttrs("MoveEffectChanceMultiplierAbAttr", user, null, !showAbility, moveChance, move);
+    applyAbAttrs("MoveEffectChanceMultiplierAbAttr", {pokemon: user, simulated: !showAbility, chance: moveChance, move});
 
     if ((!move.hasAttr("FlinchAttr") || moveChance.value <= move.chance) && !move.hasAttr("SecretPowerAttr")) {
       const userSide = user.isPlayer() ? ArenaTagSide.PLAYER : ArenaTagSide.ENEMY;
@@ -1314,7 +1320,7 @@ export class MoveEffectAttr extends MoveAttr {
     }
 
     if (!selfEffect) {
-      applyPreDefendAbAttrs("IgnoreMoveEffectsAbAttr", target, user, null, null, !showAbility, moveChance);
+      applyAbAttrs("IgnoreMoveEffectsAbAttr", {pokemon: target, move, simulated: !showAbility, chance: moveChance});
     }
     return moveChance.value;
   }
@@ -1692,8 +1698,9 @@ export class RecoilAttr extends MoveEffectAttr {
 
     const cancelled = new BooleanHolder(false);
     if (!this.unblockable) {
-      applyAbAttrs("BlockRecoilDamageAttr", user, cancelled);
-      applyAbAttrs("BlockNonDirectDamageAbAttr", user, cancelled);
+      const abAttrParams: AbAttrParamsWithCancel = {pokemon: user, cancelled};
+      applyAbAttrs("BlockRecoilDamageAttr", abAttrParams);
+      applyAbAttrs("BlockNonDirectDamageAbAttr", abAttrParams);
     }
 
     if (cancelled.value) {
@@ -1826,7 +1833,7 @@ export class HalfSacrificialAttr extends MoveEffectAttr {
 
     const cancelled = new BooleanHolder(false);
     // Check to see if the Pokemon has an ability that blocks non-direct damage
-    applyAbAttrs("BlockNonDirectDamageAbAttr", user, cancelled);
+    applyAbAttrs("BlockNonDirectDamageAbAttr", {pokemon: user, cancelled});
     if (!cancelled.value) {
       user.damageAndUpdate(toDmgValue(user.getMaxHp() / 2), { result: HitResult.INDIRECT, ignoreSegments: true });
       globalScene.phaseManager.queueMessage(i18next.t("moveTriggers:cutHpPowerUpMove", { pokemonName: getPokemonNameWithAffix(user) })); // Queue recoil message
@@ -2025,7 +2032,7 @@ export class FlameBurstAttr extends MoveEffectAttr {
     const cancelled = new BooleanHolder(false);
 
     if (!isNullOrUndefined(targetAlly)) {
-      applyAbAttrs("BlockNonDirectDamageAbAttr", targetAlly, cancelled);
+      applyAbAttrs("BlockNonDirectDamageAbAttr", {pokemon: targetAlly, cancelled});
     }
 
     if (cancelled.value || !targetAlly || targetAlly.switchOutStatus) {
@@ -2397,7 +2404,7 @@ export class MultiHitAttr extends MoveAttr {
       {
         const rand = user.randBattleSeedInt(20);
         const hitValue = new NumberHolder(rand);
-        applyAbAttrs("MaxMultiHitAbAttr", user, null, false, hitValue);
+        applyAbAttrs("MaxMultiHitAbAttr", {pokemon: user, hits: hitValue});
         if (hitValue.value >= 13) {
           return 2;
         } else if (hitValue.value >= 6) {
@@ -2505,7 +2512,7 @@ export class StatusEffectAttr extends MoveEffectAttr {
       }
       if (((!pokemon.status || this.overrideStatus) || (pokemon.status.effect === this.effect && moveChance < 0))
         && pokemon.trySetStatus(this.effect, true, user, this.turnsRemaining, null, this.overrideStatus, quiet)) {
-        applyPostAttackAbAttrs("ConfusionOnStatusEffectAbAttr", user, target, move, null, false, this.effect);
+        applyAbAttrs("ConfusionOnStatusEffectAbAttr", {pokemon: user, opponent: target, move, effect: this.effect});
         return true;
       }
     }
@@ -2557,7 +2564,7 @@ export class PsychoShiftEffectAttr extends MoveEffectAttr {
   apply(user: Pokemon, target: Pokemon, _move: Move, _args: any[]): boolean {
     const statusToApply: StatusEffect | undefined = user.status?.effect ?? (user.hasAbility(AbilityId.COMATOSE) ? StatusEffect.SLEEP : undefined);
 
-    if (target.status) {
+    if (target.status || !statusToApply) {
       return false;
     } else {
       const canSetStatus = target.canSetStatus(statusToApply, true, false, user);
@@ -2573,7 +2580,8 @@ export class PsychoShiftEffectAttr extends MoveEffectAttr {
   }
 
   getTargetBenefitScore(user: Pokemon, target: Pokemon, move: Move): number {
-    return !target.status && target.canSetStatus(user.status?.effect, true, false, user) ? -10 : 0;
+    const statusToApply = user.status?.effect ?? (user.hasAbility(AbilityId.COMATOSE) ? StatusEffect.SLEEP : undefined);
+    return !target.status && statusToApply && target.canSetStatus(statusToApply, true, false, user) ? -10 : 0;
   }
 }
 
@@ -2661,7 +2669,7 @@ export class RemoveHeldItemAttr extends MoveEffectAttr {
     // Check for abilities that block item theft
     // TODO: This should not trigger if the target would faint beforehand
     const cancelled = new BooleanHolder(false);
-    applyAbAttrs("BlockItemTheftAbAttr", target, cancelled);
+    applyAbAttrs("BlockItemTheftAbAttr", {pokemon: target, cancelled});
 
     if (cancelled.value) {
       return false;
@@ -2778,8 +2786,8 @@ export class EatBerryAttr extends MoveEffectAttr {
    protected eatBerry(consumer: Pokemon, berryOwner: Pokemon = consumer, updateHarvest = consumer === berryOwner) {
      // consumer eats berry, owner triggers unburden and similar effects
     getBerryEffectFunc(this.chosenBerry.berryType)(consumer);
-    applyPostItemLostAbAttrs("PostItemLostAbAttr", berryOwner, false);
-    applyAbAttrs("HealFromBerryUseAbAttr", consumer, new BooleanHolder(false));
+    applyAbAttrs("PostItemLostAbAttr", {pokemon: berryOwner});
+    applyAbAttrs("HealFromBerryUseAbAttr", {pokemon: consumer});
     consumer.recordEatenBerry(this.chosenBerry.berryType, updateHarvest);
   }
 }
@@ -2804,7 +2812,7 @@ export class StealEatBerryAttr extends EatBerryAttr {
   apply(user: Pokemon, target: Pokemon, move: Move, args: any[]): boolean {
     // check for abilities that block item theft
     const cancelled = new BooleanHolder(false);
-    applyAbAttrs("BlockItemTheftAbAttr", target, cancelled);
+    applyAbAttrs("BlockItemTheftAbAttr", {pokemon: target, cancelled});
     if (cancelled.value === true) {
       return false;
     }
@@ -2818,7 +2826,7 @@ export class StealEatBerryAttr extends EatBerryAttr {
 
     // pick a random berry and eat it
     this.chosenBerry = heldBerries[user.randBattleSeedInt(heldBerries.length)];
-    applyPostItemLostAbAttrs("PostItemLostAbAttr", target, false);
+    applyAbAttrs("PostItemLostAbAttr", {pokemon: target});
     const message = i18next.t("battle:stealEatBerry", { pokemonName: user.name, targetName: target.name, berryName: this.chosenBerry.type.name });
     globalScene.phaseManager.queueMessage(message);
     this.reduceBerryModifier(target);
@@ -3009,7 +3017,7 @@ export class OneHitKOAttr extends MoveAttr {
   getCondition(): MoveConditionFunc {
     return (user, target, move) => {
       const cancelled = new BooleanHolder(false);
-      applyAbAttrs("BlockOneHitKOAbAttr", target, cancelled);
+      applyAbAttrs("BlockOneHitKOAbAttr", {pokemon: target, cancelled});
       return !cancelled.value && user.level >= target.level;
     };
   }
@@ -5421,7 +5429,7 @@ export class NoEffectAttr extends MoveAttr {
 
 const crashDamageFunc = (user: Pokemon, move: Move) => {
   const cancelled = new BooleanHolder(false);
-  applyAbAttrs("BlockNonDirectDamageAbAttr", user, cancelled);
+  applyAbAttrs("BlockNonDirectDamageAbAttr", {pokemon: user, cancelled});
   if (cancelled.value) {
     return false;
   }
@@ -6420,9 +6428,9 @@ export class ForceSwitchOutAttr extends MoveEffectAttr {
   }
 
   getFailedText(_user: Pokemon, target: Pokemon, _move: Move): string | undefined {
-    const blockedByAbility = new BooleanHolder(false);
-    applyAbAttrs("ForceSwitchOutImmunityAbAttr", target, blockedByAbility);
-    if (blockedByAbility.value) {
+    const cancelled = new BooleanHolder(false);
+    applyAbAttrs("ForceSwitchOutImmunityAbAttr", {pokemon: target, cancelled});
+    if (cancelled.value) {
       return i18next.t("moveTriggers:cannotBeSwitchedOut", { pokemonName: getPokemonNameWithAffix(target) });
     }
   }
@@ -6461,7 +6469,7 @@ export class ForceSwitchOutAttr extends MoveEffectAttr {
         }
 
         const blockedByAbility = new BooleanHolder(false);
-        applyAbAttrs("ForceSwitchOutImmunityAbAttr", target, blockedByAbility);
+        applyAbAttrs("ForceSwitchOutImmunityAbAttr", {pokemon: target, cancelled: blockedByAbility});
         if (blockedByAbility.value) {
           return false;
         }
@@ -7970,7 +7978,7 @@ const failIfSingleBattle: MoveConditionFunc = (user, target, move) => globalScen
 
 const failIfDampCondition: MoveConditionFunc = (user, target, move) => {
   const cancelled = new BooleanHolder(false);
-  globalScene.getField(true).map(p=>applyAbAttrs("FieldPreventExplosiveMovesAbAttr", p, cancelled));
+  globalScene.getField(true).map(p=>applyAbAttrs("FieldPreventExplosiveMovesAbAttr", {pokemon: p, cancelled}));
   // Queue a message if an ability prevented usage of the move
   if (cancelled.value) {
     globalScene.phaseManager.queueMessage(i18next.t("moveTriggers:cannotUseMove", { pokemonName: getPokemonNameWithAffix(user), moveName: move.name }));

src/data/mystery-encounters/encounters/the-winstrate-challenge-encounter.ts

@@ -24,7 +24,7 @@ import { PokemonType } from "#enums/pokemon-type";
 import { BerryType } from "#enums/berry-type";
 import { Stat } from "#enums/stat";
 import { SpeciesFormChangeAbilityTrigger } from "#app/data/pokemon-forms/form-change-triggers";
-import { applyPostBattleInitAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { showEncounterDialogue, showEncounterText } from "#app/data/mystery-encounters/utils/encounter-dialogue-utils";
 import { MysteryEncounterMode } from "#enums/mystery-encounter-mode";
 import i18next from "i18next";
@@ -221,7 +221,7 @@ function endTrainerBattleAndShowDialogue(): Promise<void> {
 
         // Each trainer battle is supposed to be a new fight, so reset all per-battle activation effects
         pokemon.resetBattleAndWaveData();
-        applyPostBattleInitAbAttrs("PostBattleInitAbAttr", pokemon);
+        applyAbAttrs("PostBattleInitAbAttr", { pokemon });
       }
 
       globalScene.phaseManager.unshiftNew("ShowTrainerPhase");

src/field/arena.ts

@@ -20,11 +20,7 @@ import { ArenaTrapTag, getArenaTag } from "#app/data/arena-tag";
 import { ArenaTagSide } from "#enums/arena-tag-side";
 import type { BattlerIndex } from "#enums/battler-index";
 import { Terrain, TerrainType } from "#app/data/terrain";
-import {
-  applyAbAttrs,
-  applyPostTerrainChangeAbAttrs,
-  applyPostWeatherChangeAbAttrs,
-} from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import type Pokemon from "#app/field/pokemon";
 import Overrides from "#app/overrides";
 import { TagAddedEvent, TagRemovedEvent, TerrainChangedEvent, WeatherChangedEvent } from "#app/events/arena";
@@ -372,7 +368,7 @@ export class Arena {
         pokemon.findAndRemoveTags(
           t => "weatherTypes" in t && !(t.weatherTypes as WeatherType[]).find(t => t === weather),
         );
-        applyPostWeatherChangeAbAttrs("PostWeatherChangeAbAttr", pokemon, weather);
+        applyAbAttrs("PostWeatherChangeAbAttr", { pokemon, weather });
       });
 
     return true;
@@ -461,8 +457,8 @@ export class Arena {
         pokemon.findAndRemoveTags(
           t => "terrainTypes" in t && !(t.terrainTypes as TerrainType[]).find(t => t === terrain),
         );
-        applyPostTerrainChangeAbAttrs("PostTerrainChangeAbAttr", pokemon, terrain);
-        applyAbAttrs("TerrainEventTypeChangeAbAttr", pokemon, null, false);
+        applyAbAttrs("PostTerrainChangeAbAttr", { pokemon, terrain });
+        applyAbAttrs("TerrainEventTypeChangeAbAttr", { pokemon });
       });
 
     return true;

src/field/pokemon.ts

@@ -108,23 +108,8 @@ import { WeatherType } from "#enums/weather-type";
 import { NoCritTag, WeakenMoveScreenTag } from "#app/data/arena-tag";
 import { ArenaTagSide } from "#enums/arena-tag-side";
 import type { SuppressAbilitiesTag } from "#app/data/arena-tag";
-import type { Ability } from "#app/data/abilities/ability";
-import {
-  applyAbAttrs,
-  applyStatMultiplierAbAttrs,
-  applyPreApplyBattlerTagAbAttrs,
-  applyPreAttackAbAttrs,
-  applyPreDefendAbAttrs,
-  applyPreSetStatusAbAttrs,
-  applyFieldStatMultiplierAbAttrs,
-  applyCheckTrappedAbAttrs,
-  applyPostDamageAbAttrs,
-  applyPostItemLostAbAttrs,
-  applyOnGainAbAttrs,
-  applyPreLeaveFieldAbAttrs,
-  applyOnLoseAbAttrs,
-  applyAllyStatMultiplierAbAttrs,
-} from "#app/data/abilities/apply-ab-attrs";
+import type { Ability, PreAttackModifyDamageAbAttrParams } from "#app/data/abilities/ability";
+import { applyAbAttrs, applyOnGainAbAttrs, applyOnLoseAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { allAbilities } from "#app/data/data-lists";
 import type PokemonData from "#app/system/pokemon-data";
 import { BattlerIndex } from "#enums/battler-index";
@@ -189,7 +174,7 @@ import { HitResult } from "#enums/hit-result";
 import { AiType } from "#enums/ai-type";
 import type { MoveResult } from "#enums/move-result";
 import { PokemonMove } from "#app/data/moves/pokemon-move";
-import type { AbAttrMap, AbAttrString } from "#app/@types/ability-types";
+import type { AbAttrMap, AbAttrString, TypeMultiplierAbAttrParams } from "#app/@types/ability-types";
 
 /** Base typeclass for damage parameter methods, used for DRY */
 type damageParams = {
@@ -1364,7 +1349,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     applyMoveAttrs("HighCritAttr", source, this, move, critStage);
     globalScene.applyModifiers(CritBoosterModifier, source.isPlayer(), source, critStage);
     globalScene.applyModifiers(TempCritBoosterModifier, source.isPlayer(), critStage);
-    applyAbAttrs("BonusCritAbAttr", source, null, false, critStage);
+    applyAbAttrs("BonusCritAbAttr", { pokemon: source, critStage });
     const critBoostTag = source.getTag(CritBoostTag);
     if (critBoostTag) {
       // Dragon cheer only gives +1 crit stage to non-dragon types
@@ -1415,46 +1400,52 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     simulated = true,
     ignoreHeldItems = false,
   ): number {
-    const statValue = new NumberHolder(this.getStat(stat, false));
+    const statVal = new NumberHolder(this.getStat(stat, false));
     if (!ignoreHeldItems) {
-      globalScene.applyModifiers(StatBoosterModifier, this.isPlayer(), this, stat, statValue);
+      globalScene.applyModifiers(StatBoosterModifier, this.isPlayer(), this, stat, statVal);
     }
 
     // The Ruin abilities here are never ignored, but they reveal themselves on summon anyway
     const fieldApplied = new BooleanHolder(false);
     for (const pokemon of globalScene.getField(true)) {
-      applyFieldStatMultiplierAbAttrs(
-        "FieldMultiplyStatAbAttr",
+      applyAbAttrs("FieldMultiplyStatAbAttr", {
         pokemon,
         stat,
-        statValue,
-        this,
-        fieldApplied,
+        statVal,
+        target: this,
+        hasApplied: fieldApplied,
         simulated,
-      );
+      });
       if (fieldApplied.value) {
         break;
       }
     }
     if (!ignoreAbility) {
-      applyStatMultiplierAbAttrs("StatMultiplierAbAttr", this, stat, statValue, simulated);
+      applyAbAttrs("StatMultiplierAbAttr", {
+        pokemon: this,
+        stat,
+        statVal,
+        simulated,
+        // TODO: maybe just don't call this if the move is none?
+        move: move ?? allMoves[MoveId.NONE],
+      });
     }
 
     const ally = this.getAlly();
     if (!isNullOrUndefined(ally)) {
-      applyAllyStatMultiplierAbAttrs(
-        "AllyStatMultiplierAbAttr",
-        ally,
+      applyAbAttrs("AllyStatMultiplierAbAttr", {
+        pokemon: ally,
         stat,
-        statValue,
+        statVal,
         simulated,
-        this,
-        move?.hasFlag(MoveFlags.IGNORE_ABILITIES) || ignoreAllyAbility,
-      );
+        // TODO: maybe just don't call this if the move is none?
+        move: move ?? allMoves[MoveId.NONE],
+        ignoreAbility: move?.hasFlag(MoveFlags.IGNORE_ABILITIES) || ignoreAllyAbility,
+      });
     }
 
     let ret =
-      statValue.value *
+      statVal.value *
       this.getStatStageMultiplier(stat, opponent, move, ignoreOppAbility, isCritical, simulated, ignoreHeldItems);
 
     switch (stat) {
@@ -2045,20 +2036,20 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
    * @param ability New Ability
    */
   public setTempAbility(ability: Ability, passive = false): void {
-    applyOnLoseAbAttrs(this, passive);
+    applyOnLoseAbAttrs({ pokemon: this, passive });
     if (passive) {
       this.summonData.passiveAbility = ability.id;
     } else {
       this.summonData.ability = ability.id;
     }
-    applyOnGainAbAttrs(this, passive);
+    applyOnGainAbAttrs({ pokemon: this, passive });
   }
 
   /**
    * Suppresses an ability and calls its onlose attributes
    */
   public suppressAbility() {
-    [true, false].forEach(passive => applyOnLoseAbAttrs(this, passive));
+    [true, false].forEach(passive => applyOnLoseAbAttrs({ pokemon: this, passive }));
     this.summonData.abilitySuppressed = true;
   }
 
@@ -2194,7 +2185,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     const weight = new NumberHolder(this.species.weight - weightRemoved);
 
     // This will trigger the ability overlay so only call this function when necessary
-    applyAbAttrs("WeightMultiplierAbAttr", this, null, false, weight);
+    applyAbAttrs("WeightMultiplierAbAttr", { pokemon: this, weight });
     return Math.max(minWeight, weight.value);
   }
 
@@ -2256,7 +2247,8 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
       return false;
     }
 
-    const trappedByAbility = new BooleanHolder(false);
+    /** Holds whether the pokemon is trapped due to an ability */
+    const trapped = new BooleanHolder(false);
     /**
      * Contains opposing Pokemon (Enemy/Player Pokemon) depending on perspective
      * Afterwards, it filters out Pokemon that have been switched out of the field so trapped abilities/moves do not trigger
@@ -2265,14 +2257,12 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     const opposingField = opposingFieldUnfiltered.filter(enemyPkm => enemyPkm.switchOutStatus === false);
 
     for (const opponent of opposingField) {
-      applyCheckTrappedAbAttrs("CheckTrappedAbAttr", opponent, trappedByAbility, this, trappedAbMessages, simulated);
+      applyAbAttrs("CheckTrappedAbAttr", { pokemon: opponent, trapped, opponent: this, simulated }, trappedAbMessages);
     }
 
     const side = this.isPlayer() ? ArenaTagSide.PLAYER : ArenaTagSide.ENEMY;
     return (
-      trappedByAbility.value ||
-      !!this.getTag(TrappedTag) ||
-      !!globalScene.arena.getTagOnSide(ArenaTagType.FAIRY_LOCK, side)
+      trapped.value || !!this.getTag(TrappedTag) || !!globalScene.arena.getTagOnSide(ArenaTagType.FAIRY_LOCK, side)
     );
   }
 
@@ -2287,7 +2277,16 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     const moveTypeHolder = new NumberHolder(move.type);
 
     applyMoveAttrs("VariableMoveTypeAttr", this, null, move, moveTypeHolder);
-    applyPreAttackAbAttrs("MoveTypeChangeAbAttr", this, null, move, simulated, moveTypeHolder);
+
+    const power = new NumberHolder(move.power);
+    applyAbAttrs("MoveTypeChangeAbAttr", {
+      pokemon: this,
+      move,
+      simulated,
+      moveType: moveTypeHolder,
+      power,
+      opponent: this,
+    });
 
     // If the user is terastallized and the move is tera blast, or tera starstorm that is stellar type,
     // then bypass the check for ion deluge and electrify
@@ -2351,17 +2350,31 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     }
 
     const cancelledHolder = cancelled ?? new BooleanHolder(false);
+    // TypeMultiplierAbAttrParams is shared amongst the type of AbAttrs we will be invoking
+    const commonAbAttrParams: TypeMultiplierAbAttrParams = {
+      pokemon: this,
+      opponent: source,
+      move,
+      cancelled: cancelledHolder,
+      simulated,
+      typeMultiplier,
+    };
     if (!ignoreAbility) {
-      applyPreDefendAbAttrs("TypeImmunityAbAttr", this, source, move, cancelledHolder, simulated, typeMultiplier);
+      applyAbAttrs("TypeImmunityAbAttr", commonAbAttrParams);
 
       if (!cancelledHolder.value) {
-        applyPreDefendAbAttrs("MoveImmunityAbAttr", this, source, move, cancelledHolder, simulated, typeMultiplier);
+        applyAbAttrs("MoveImmunityAbAttr", commonAbAttrParams);
       }
 
       if (!cancelledHolder.value) {
         const defendingSidePlayField = this.isPlayer() ? globalScene.getPlayerField() : globalScene.getEnemyField();
         defendingSidePlayField.forEach(p =>
-          applyPreDefendAbAttrs("FieldPriorityMoveImmunityAbAttr", p, source, move, cancelledHolder),
+          applyAbAttrs("FieldPriorityMoveImmunityAbAttr", {
+            pokemon: p,
+            opponent: source,
+            move,
+            cancelled: cancelledHolder,
+          }),
         );
       }
     }
@@ -2376,7 +2389,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
 
     // Apply Tera Shell's effect to attacks after all immunities are accounted for
     if (!ignoreAbility && move.category !== MoveCategory.STATUS) {
-      applyPreDefendAbAttrs("FullHpResistTypeAbAttr", this, source, move, cancelledHolder, simulated, typeMultiplier);
+      applyAbAttrs("FullHpResistTypeAbAttr", commonAbAttrParams);
     }
 
     if (move.category === MoveCategory.STATUS && move.hitsSubstitute(source, this)) {
@@ -2420,16 +2433,22 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     }
 
     let multiplier = types
-      .map(defType => {
-        const multiplier = new NumberHolder(getTypeDamageMultiplier(moveType, defType));
+      .map(defenderType => {
+        const multiplier = new NumberHolder(getTypeDamageMultiplier(moveType, defenderType));
         applyChallenges(ChallengeType.TYPE_EFFECTIVENESS, multiplier);
         if (move) {
-          applyMoveAttrs("VariableMoveTypeChartAttr", null, this, move, multiplier, defType);
+          applyMoveAttrs("VariableMoveTypeChartAttr", null, this, move, multiplier, defenderType);
         }
         if (source) {
           const ignoreImmunity = new BooleanHolder(false);
           if (source.isActive(true) && source.hasAbilityWithAttr("IgnoreTypeImmunityAbAttr")) {
-            applyAbAttrs("IgnoreTypeImmunityAbAttr", source, ignoreImmunity, simulated, moveType, defType);
+            applyAbAttrs("IgnoreTypeImmunityAbAttr", {
+              pokemon: source,
+              cancelled: ignoreImmunity,
+              simulated,
+              moveType,
+              defenderType,
+            });
           }
           if (ignoreImmunity.value) {
             if (multiplier.value === 0) {
@@ -2438,7 +2457,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
           }
 
           const exposedTags = this.findTags(tag => tag instanceof ExposedTag) as ExposedTag[];
-          if (exposedTags.some(t => t.ignoreImmunity(defType, moveType))) {
+          if (exposedTags.some(t => t.ignoreImmunity(defenderType, moveType))) {
             if (multiplier.value === 0) {
               return 1;
             }
@@ -3358,7 +3377,12 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
         }
       }
       if (!ignoreOppAbility) {
-        applyAbAttrs("IgnoreOpponentStatStagesAbAttr", opponent, null, simulated, stat, ignoreStatStage);
+        applyAbAttrs("IgnoreOpponentStatStagesAbAttr", {
+          pokemon: opponent,
+          ignored: ignoreStatStage,
+          stat,
+          simulated,
+        });
       }
       if (move) {
         applyMoveAttrs("IgnoreOpponentStatStagesAttr", this, opponent, move, ignoreStatStage);
@@ -3397,8 +3421,9 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     const ignoreAccStatStage = new BooleanHolder(false);
     const ignoreEvaStatStage = new BooleanHolder(false);
 
-    applyAbAttrs("IgnoreOpponentStatStagesAbAttr", target, null, false, Stat.ACC, ignoreAccStatStage);
-    applyAbAttrs("IgnoreOpponentStatStagesAbAttr", this, null, false, Stat.EVA, ignoreEvaStatStage);
+    // TODO: consider refactoring this method to accept `simulated` and then pass simulated to these applyAbAttrs
+    applyAbAttrs("IgnoreOpponentStatStagesAbAttr", { pokemon: target, stat: Stat.ACC, ignored: ignoreAccStatStage });
+    applyAbAttrs("IgnoreOpponentStatStagesAbAttr", { pokemon: this, stat: Stat.EVA, ignored: ignoreEvaStatStage });
     applyMoveAttrs("IgnoreOpponentStatStagesAttr", this, target, sourceMove, ignoreEvaStatStage);
 
     globalScene.applyModifiers(TempStatStageBoosterModifier, this.isPlayer(), Stat.ACC, userAccStage);
@@ -3418,33 +3443,40 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
           : 3 / (3 + Math.min(targetEvaStage.value - userAccStage.value, 6));
     }
 
-    applyStatMultiplierAbAttrs("StatMultiplierAbAttr", this, Stat.ACC, accuracyMultiplier, false, sourceMove);
+    applyAbAttrs("StatMultiplierAbAttr", {
+      pokemon: this,
+      stat: Stat.ACC,
+      statVal: accuracyMultiplier,
+      move: sourceMove,
+    });
 
     const evasionMultiplier = new NumberHolder(1);
-    applyStatMultiplierAbAttrs("StatMultiplierAbAttr", target, Stat.EVA, evasionMultiplier);
+    applyAbAttrs("StatMultiplierAbAttr", {
+      pokemon: target,
+      stat: Stat.EVA,
+      statVal: evasionMultiplier,
+      move: sourceMove,
+    });
 
     const ally = this.getAlly();
     if (!isNullOrUndefined(ally)) {
       const ignore =
         this.hasAbilityWithAttr("MoveAbilityBypassAbAttr") || sourceMove.hasFlag(MoveFlags.IGNORE_ABILITIES);
-      applyAllyStatMultiplierAbAttrs(
-        "AllyStatMultiplierAbAttr",
-        ally,
-        Stat.ACC,
-        accuracyMultiplier,
-        false,
-        this,
-        ignore,
-      );
-      applyAllyStatMultiplierAbAttrs(
-        "AllyStatMultiplierAbAttr",
-        ally,
-        Stat.EVA,
-        evasionMultiplier,
-        false,
-        this,
-        ignore,
-      );
+      applyAbAttrs("AllyStatMultiplierAbAttr", {
+        pokemon: ally,
+        stat: Stat.ACC,
+        statVal: accuracyMultiplier,
+        ignoreAbility: ignore,
+        move: sourceMove,
+      });
+
+      applyAbAttrs("AllyStatMultiplierAbAttr", {
+        pokemon: ally,
+        stat: Stat.EVA,
+        statVal: evasionMultiplier,
+        ignoreAbility: ignore,
+        move: sourceMove,
+      });
     }
 
     return accuracyMultiplier.value / evasionMultiplier.value;
@@ -3559,7 +3591,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     applyMoveAttrs("CombinedPledgeStabBoostAttr", source, this, move, stabMultiplier);
 
     if (!ignoreSourceAbility) {
-      applyAbAttrs("StabBoostAbAttr", source, null, simulated, stabMultiplier);
+      applyAbAttrs("StabBoostAbAttr", { pokemon: source, simulated, multiplier: stabMultiplier });
     }
 
     if (source.isTerastallized && sourceTeraType === moveType && moveType !== PokemonType.STELLAR) {
@@ -3706,16 +3738,14 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
       null,
       multiStrikeEnhancementMultiplier,
     );
+
     if (!ignoreSourceAbility) {
-      applyPreAttackAbAttrs(
-        "AddSecondStrikeAbAttr",
-        source,
-        this,
+      applyAbAttrs("AddSecondStrikeAbAttr", {
+        pokemon: source,
         move,
         simulated,
-        null,
-        multiStrikeEnhancementMultiplier,
-      );
+        multiplier: multiStrikeEnhancementMultiplier,
+      });
     }
 
     /** Doubles damage if this Pokemon's last move was Glaive Rush */
@@ -3726,7 +3756,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
 
     /** The damage multiplier when the given move critically hits */
     const criticalMultiplier = new NumberHolder(isCritical ? 1.5 : 1);
-    applyAbAttrs("MultCritAbAttr", source, null, simulated, criticalMultiplier);
+    applyAbAttrs("MultCritAbAttr", { pokemon: source, simulated, critMult: criticalMultiplier });
 
     /**
      * A multiplier for random damage spread in the range [0.85, 1]
@@ -3747,7 +3777,11 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     ) {
       const burnDamageReductionCancelled = new BooleanHolder(false);
       if (!ignoreSourceAbility) {
-        applyAbAttrs("BypassBurnDamageReductionAbAttr", source, burnDamageReductionCancelled, simulated);
+        applyAbAttrs("BypassBurnDamageReductionAbAttr", {
+          pokemon: source,
+          cancelled: burnDamageReductionCancelled,
+          simulated,
+        });
       }
       if (!burnDamageReductionCancelled.value) {
         burnMultiplier = 0.5;
@@ -3811,7 +3845,13 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
 
     /** Doubles damage if the attacker has Tinted Lens and is using a resisted move */
     if (!ignoreSourceAbility) {
-      applyPreAttackAbAttrs("DamageBoostAbAttr", source, this, move, simulated, damage);
+      applyAbAttrs("DamageBoostAbAttr", {
+        pokemon: source,
+        opponent: this,
+        move,
+        simulated,
+        damage,
+      });
     }
 
     /** Apply the enemy's Damage and Resistance tokens */
@@ -3822,14 +3862,25 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
       globalScene.applyModifiers(EnemyDamageReducerModifier, false, damage);
     }
 
+    const abAttrParams: PreAttackModifyDamageAbAttrParams = {
+      pokemon: this,
+      opponent: source,
+      move,
+      simulated,
+      damage,
+    };
     /** Apply this Pokemon's post-calc defensive modifiers (e.g. Fur Coat) */
     if (!ignoreAbility) {
-      applyPreDefendAbAttrs("ReceivedMoveDamageMultiplierAbAttr", this, source, move, cancelled, simulated, damage);
+      applyAbAttrs("ReceivedMoveDamageMultiplierAbAttr", abAttrParams);
 
       const ally = this.getAlly();
       /** Additionally apply friend guard damage reduction if ally has it. */
       if (globalScene.currentBattle.double && !isNullOrUndefined(ally) && ally.isActive(true)) {
-        applyPreDefendAbAttrs("AlliedFieldDamageReductionAbAttr", ally, source, move, cancelled, simulated, damage);
+        applyAbAttrs("AlliedFieldDamageReductionAbAttr", {
+          ...abAttrParams,
+          // Same parameters as before, except we are applying the ally's ability
+          pokemon: ally,
+        });
       }
     }
 
@@ -3837,7 +3888,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     applyMoveAttrs("ModifiedDamageAttr", source, this, move, damage);
 
     if (this.isFullHp() && !ignoreAbility) {
-      applyPreDefendAbAttrs("PreDefendFullHpEndureAbAttr", this, source, move, cancelled, false, damage);
+      applyAbAttrs("PreDefendFullHpEndureAbAttr", abAttrParams);
     }
 
     // debug message for when damage is applied (i.e. not simulated)
@@ -3875,7 +3926,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
 
     const alwaysCrit = new BooleanHolder(false);
     applyMoveAttrs("CritOnlyAttr", source, this, move, alwaysCrit);
-    applyAbAttrs("ConditionalCritAbAttr", source, null, false, alwaysCrit, this, move);
+    applyAbAttrs("ConditionalCritAbAttr", { pokemon: source, isCritical: alwaysCrit, target: this, move });
     const alwaysCritTag = !!source.getTag(BattlerTagType.ALWAYS_CRIT);
     const critChance = [24, 8, 2, 1][Phaser.Math.Clamp(this.getCritStage(source, move), 0, 3)];
 
@@ -3886,7 +3937,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
 
     // apply crit block effects from lucky chant & co., overriding previous effects
     const blockCrit = new BooleanHolder(false);
-    applyAbAttrs("BlockCritAbAttr", this, null, false, blockCrit);
+    applyAbAttrs("BlockCritAbAttr", { pokemon: this, blockCrit });
     const blockCritTag = globalScene.arena.getTagOnSide(
       NoCritTag,
       this.isPlayer() ? ArenaTagSide.PLAYER : ArenaTagSide.ENEMY,
@@ -3998,7 +4049,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
      * Multi-hits are handled in move-effect-phase.ts for PostDamageAbAttr
      */
     if (!source || source.turnData.hitCount <= 1) {
-      applyPostDamageAbAttrs("PostDamageAbAttr", this, damage, this.hasPassive(), false, [], source);
+      applyAbAttrs("PostDamageAbAttr", { pokemon: this, damage, source });
     }
     return damage;
   }
@@ -4046,11 +4097,17 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     const stubTag = new BattlerTag(tagType, 0, 0);
 
     const cancelled = new BooleanHolder(false);
-    applyPreApplyBattlerTagAbAttrs("BattlerTagImmunityAbAttr", this, stubTag, cancelled, true);
+    applyAbAttrs("BattlerTagImmunityAbAttr", { pokemon: this, tag: stubTag, cancelled, simulated: true });
 
     const userField = this.getAlliedField();
     userField.forEach(pokemon =>
-      applyPreApplyBattlerTagAbAttrs("UserFieldBattlerTagImmunityAbAttr", pokemon, stubTag, cancelled, true, this),
+      applyAbAttrs("UserFieldBattlerTagImmunityAbAttr", {
+        pokemon,
+        tag: stubTag,
+        cancelled,
+        simulated: true,
+        target: this,
+      }),
     );
 
     return !cancelled.value;
@@ -4066,13 +4123,13 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     const newTag = getBattlerTag(tagType, turnCount, sourceMove!, sourceId!); // TODO: are the bangs correct?
 
     const cancelled = new BooleanHolder(false);
-    applyPreApplyBattlerTagAbAttrs("BattlerTagImmunityAbAttr", this, newTag, cancelled);
+    applyAbAttrs("BattlerTagImmunityAbAttr", { pokemon: this, tag: newTag, cancelled });
     if (cancelled.value) {
       return false;
     }
 
     for (const pokemon of this.getAlliedField()) {
-      applyPreApplyBattlerTagAbAttrs("UserFieldBattlerTagImmunityAbAttr", pokemon, newTag, cancelled, false, this);
+      applyAbAttrs("UserFieldBattlerTagImmunityAbAttr", { pokemon, tag: newTag, cancelled, target: this });
       if (cancelled.value) {
         return false;
       }
@@ -4597,7 +4654,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
    * @param ignoreField Whether any field effects (weather, terrain, etc.) should be considered
    */
   canSetStatus(
-    effect: StatusEffect | undefined,
+    effect: StatusEffect,
     quiet = false,
     overrideStatus = false,
     sourcePokemon: Pokemon | null = null,
@@ -4628,8 +4685,14 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
 
           // Check if the source Pokemon has an ability that cancels the Poison/Toxic immunity
           const cancelImmunity = new BooleanHolder(false);
+          // TODO: Determine if we need to pass `quiet` as the value for simulated in this call
           if (sourcePokemon) {
-            applyAbAttrs("IgnoreTypeStatusEffectImmunityAbAttr", sourcePokemon, cancelImmunity, false, effect, defType);
+            applyAbAttrs("IgnoreTypeStatusEffectImmunityAbAttr", {
+              pokemon: sourcePokemon,
+              cancelled: cancelImmunity,
+              statusEffect: effect,
+              defenderType: defType,
+            });
             if (cancelImmunity.value) {
               return false;
             }
@@ -4678,21 +4741,20 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     }
 
     const cancelled = new BooleanHolder(false);
-    applyPreSetStatusAbAttrs("StatusEffectImmunityAbAttr", this, effect, cancelled, quiet);
+    applyAbAttrs("StatusEffectImmunityAbAttr", { pokemon: this, effect, cancelled, simulated: quiet });
     if (cancelled.value) {
       return false;
     }
 
     for (const pokemon of this.getAlliedField()) {
-      applyPreSetStatusAbAttrs(
-        "UserFieldStatusEffectImmunityAbAttr",
+      applyAbAttrs("UserFieldStatusEffectImmunityAbAttr", {
         pokemon,
         effect,
         cancelled,
-        quiet,
-        this,
-        sourcePokemon,
-      );
+        simulated: quiet,
+        target: this,
+        source: sourcePokemon,
+      });
       if (cancelled.value) {
         break;
       }
@@ -4723,6 +4785,9 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     overrideStatus?: boolean,
     quiet = true,
   ): boolean {
+    if (!effect) {
+      return false;
+    }
     if (!this.canSetStatus(effect, quiet, overrideStatus, sourcePokemon)) {
       return false;
     }
@@ -4781,7 +4846,6 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     }
 
     sleepTurnsRemaining = sleepTurnsRemaining!; // tell TS compiler it's defined
-    effect = effect!; // If `effect` is undefined then `trySetStatus()` will have already returned early via the `canSetStatus()` call
     this.status = new Status(effect, 0, sleepTurnsRemaining?.value);
 
     return true;
@@ -4842,7 +4906,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     if (globalScene.arena.getTagOnSide(ArenaTagType.SAFEGUARD, defendingSide)) {
       const bypassed = new BooleanHolder(false);
       if (attacker) {
-        applyAbAttrs("InfiltratorAbAttr", attacker, null, false, bypassed);
+        applyAbAttrs("InfiltratorAbAttr", { pokemon: attacker, bypassed });
       }
       return !bypassed.value;
     }
@@ -5391,7 +5455,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
       this.hideInfo();
     }
     // Trigger abilities that activate upon leaving the field
-    applyPreLeaveFieldAbAttrs("PreLeaveFieldAbAttr", this);
+    applyAbAttrs("PreLeaveFieldAbAttr", { pokemon: this });
     this.setSwitchOutStatus(true);
     globalScene.triggerPokemonFormChange(this, SpeciesFormChangeActiveTrigger, true);
     globalScene.field.remove(this, destroy);
@@ -5451,7 +5515,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
       globalScene.removeModifier(heldItem, this.isEnemy());
     }
     if (forBattle) {
-      applyPostItemLostAbAttrs("PostItemLostAbAttr", this, false);
+      applyAbAttrs("PostItemLostAbAttr", { pokemon: this });
     }
 
     return true;

src/modifier/modifier.ts

@@ -42,7 +42,7 @@ import type {
 import { getModifierType } from "#app/utils/modifier-utils";
 import { Color, ShadowColor } from "#enums/color";
 import { FRIENDSHIP_GAIN_FROM_RARE_CANDY } from "#app/data/balance/starters";
-import { applyAbAttrs, applyPostItemLostAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { globalScene } from "#app/global-scene";
 import type { ModifierInstanceMap, ModifierString } from "#app/@types/modifier-types";
 
@@ -1879,7 +1879,7 @@ export class BerryModifier extends PokemonHeldItemModifier {
 
     // munch the berry and trigger unburden-like effects
     getBerryEffectFunc(this.berryType)(pokemon);
-    applyPostItemLostAbAttrs("PostItemLostAbAttr", pokemon, false);
+    applyAbAttrs("PostItemLostAbAttr", { pokemon });
 
     // Update berry eaten trackers for Belch, Harvest, Cud Chew, etc.
     // Don't recover it if we proc berry pouch (no item duplication)
@@ -1967,7 +1967,7 @@ export class PokemonInstantReviveModifier extends PokemonHeldItemModifier {
     // Reapply Commander on the Pokemon's side of the field, if applicable
     const field = pokemon.isPlayer() ? globalScene.getPlayerField() : globalScene.getEnemyField();
     for (const p of field) {
-      applyAbAttrs("CommanderAbAttr", p, null, false);
+      applyAbAttrs("CommanderAbAttr", { pokemon: p });
     }
     return true;
   }

src/phases/attempt-run-phase.ts

@@ -1,4 +1,4 @@
-import { applyAbAttrs, applyPreLeaveFieldAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { Stat } from "#enums/stat";
 import { StatusEffect } from "#enums/status-effect";
 import type { PlayerPokemon, EnemyPokemon } from "#app/field/pokemon";
@@ -25,10 +25,10 @@ export class AttemptRunPhase extends PokemonPhase {
 
     this.attemptRunAway(playerField, enemyField, escapeChance);
 
-    applyAbAttrs("RunSuccessAbAttr", playerPokemon, null, false, escapeChance);
+    applyAbAttrs("RunSuccessAbAttr", { pokemon: playerPokemon, chance: escapeChance });
 
     if (playerPokemon.randBattleSeedInt(100) < escapeChance.value && !this.forceFailEscape) {
-      enemyField.forEach(enemyPokemon => applyPreLeaveFieldAbAttrs("PreLeaveFieldAbAttr", enemyPokemon));
+      enemyField.forEach(enemyPokemon => applyAbAttrs("PreLeaveFieldAbAttr", { pokemon: enemyPokemon }));
 
       globalScene.playSound("se/flee");
       globalScene.phaseManager.queueMessage(i18next.t("battle:runAwaySuccess"), null, true, 500);
@@ -38,14 +38,11 @@ export class AttemptRunPhase extends PokemonPhase {
         alpha: 0,
         duration: 250,
         ease: "Sine.easeIn",
-        onComplete: () =>
-          // biome-ignore lint/complexity/noForEach: TODO
-          enemyField.forEach(enemyPokemon => enemyPokemon.destroy()),
+        onComplete: () => enemyField.forEach(enemyPokemon => enemyPokemon.destroy()),
       });
 
       globalScene.clearEnemyHeldItemModifiers();
 
-      // biome-ignore lint/complexity/noForEach: TODO
       enemyField.forEach(enemyPokemon => {
         enemyPokemon.hideInfo().then(() => enemyPokemon.destroy());
         enemyPokemon.hp = 0;

src/phases/battle-end-phase.ts

@@ -1,5 +1,5 @@
 import { globalScene } from "#app/global-scene";
-import { applyPostBattleAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { LapsingPersistentModifier, LapsingPokemonHeldItemModifier } from "#app/modifier/modifier";
 import { BattlePhase } from "./battle-phase";
 
@@ -65,7 +65,7 @@ export class BattleEndPhase extends BattlePhase {
     }
 
     for (const pokemon of globalScene.getPokemonAllowedInBattle()) {
-      applyPostBattleAbAttrs("PostBattleAbAttr", pokemon, false, this.isVictory);
+      applyAbAttrs("PostBattleAbAttr", { pokemon, victory: this.isVictory });
     }
 
     if (globalScene.currentBattle.moneyScattered) {

src/phases/berry-phase.ts

@@ -20,7 +20,7 @@ export class BerryPhase extends FieldPhase {
 
     this.executeForAll(pokemon => {
       this.eatBerries(pokemon);
-      applyAbAttrs("RepeatBerryNextTurnAbAttr", pokemon, null);
+      applyAbAttrs("CudChewConsumeBerryAbAttr", { pokemon });
     });
 
     this.end();
@@ -42,7 +42,7 @@ export class BerryPhase extends FieldPhase {
 
     // TODO: If both opponents on field have unnerve, which one displays its message?
     const cancelled = new BooleanHolder(false);
-    pokemon.getOpponents().forEach(opp => applyAbAttrs("PreventBerryUseAbAttr", opp, cancelled));
+    pokemon.getOpponents().forEach(opp => applyAbAttrs("PreventBerryUseAbAttr", { pokemon: opp, cancelled }));
     if (cancelled.value) {
       globalScene.phaseManager.queueMessage(
         i18next.t("abilityTriggers:preventBerryUse", {
@@ -70,6 +70,6 @@ export class BerryPhase extends FieldPhase {
     globalScene.updateModifiers(pokemon.isPlayer());
 
     // AbilityId.CHEEK_POUCH only works once per round of nom noms
-    applyAbAttrs("HealFromBerryUseAbAttr", pokemon, new BooleanHolder(false));
+    applyAbAttrs("HealFromBerryUseAbAttr", { pokemon });
   }
 }

src/phases/encounter-phase.ts

@@ -2,7 +2,7 @@ import { BattlerIndex } from "#enums/battler-index";
 import { BattleType } from "#enums/battle-type";
 import { globalScene } from "#app/global-scene";
 import { PLAYER_PARTY_MAX_SIZE } from "#app/constants";
-import { applyAbAttrs, applyPreSummonAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { initEncounterAnims, loadEncounterAnimAssets } from "#app/data/battle-anims";
 import { getCharVariantFromDialogue } from "#app/data/dialogue";
 import { getEncounterText } from "#app/data/mystery-encounters/utils/encounter-dialogue-utils";
@@ -128,7 +128,7 @@ export class EncounterPhase extends BattlePhase {
             .slice(0, !battle.double ? 1 : 2)
             .reverse()
             .forEach(playerPokemon => {
-              applyAbAttrs("SyncEncounterNatureAbAttr", playerPokemon, null, false, battle.enemyParty[e]);
+              applyAbAttrs("SyncEncounterNatureAbAttr", { pokemon: playerPokemon, target: battle.enemyParty[e] });
             });
         }
       }
@@ -249,7 +249,7 @@ export class EncounterPhase extends BattlePhase {
         if (e < (battle.double ? 2 : 1)) {
           if (battle.battleType === BattleType.WILD) {
             for (const pokemon of globalScene.getField()) {
-              applyPreSummonAbAttrs("PreSummonAbAttr", pokemon, []);
+              applyAbAttrs("PreSummonAbAttr", { pokemon });
             }
             globalScene.field.add(enemyPokemon);
             battle.seenEnemyPartyMemberIds.add(enemyPokemon.id);

src/phases/faint-phase.ts

@@ -1,11 +1,7 @@
 import type { BattlerIndex } from "#enums/battler-index";
 import { BattleType } from "#enums/battle-type";
 import { globalScene } from "#app/global-scene";
-import {
-  applyPostFaintAbAttrs,
-  applyPostKnockOutAbAttrs,
-  applyPostVictoryAbAttrs,
-} from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { BattlerTagLapseType } from "#enums/battler-tag-lapse-type";
 import { battleSpecDialogue } from "#app/data/dialogue";
 import { allMoves } from "#app/data/data-lists";
@@ -117,29 +113,31 @@ export class FaintPhase extends PokemonPhase {
 
     pokemon.resetTera();
 
+    // TODO: this can be simplified by just checking whether lastAttack is defined
     if (pokemon.turnData.attacksReceived?.length) {
       const lastAttack = pokemon.turnData.attacksReceived[0];
-      applyPostFaintAbAttrs(
-        "PostFaintAbAttr",
-        pokemon,
-        globalScene.getPokemonById(lastAttack.sourceId)!,
-        new PokemonMove(lastAttack.move).getMove(),
-        lastAttack.result,
-      ); // TODO: is this bang correct?
+      applyAbAttrs("PostFaintAbAttr", {
+        pokemon: pokemon,
+        // TODO: We should refactor lastAttack's sourceId to forbid null and just use undefined
+        attacker: globalScene.getPokemonById(lastAttack.sourceId) ?? undefined,
+        // TODO: improve the way that we provide the move that knocked out the pokemon...
+        move: new PokemonMove(lastAttack.move).getMove(),
+        hitResult: lastAttack.result,
+      }); // TODO: is this bang correct?
     } else {
       //If killed by indirect damage, apply post-faint abilities without providing a last move
-      applyPostFaintAbAttrs("PostFaintAbAttr", pokemon);
+      applyAbAttrs("PostFaintAbAttr", { pokemon });
     }
 
     const alivePlayField = globalScene.getField(true);
     for (const p of alivePlayField) {
-      applyPostKnockOutAbAttrs("PostKnockOutAbAttr", p, pokemon);
+      applyAbAttrs("PostKnockOutAbAttr", { pokemon: p, victim: pokemon });
     }
     if (pokemon.turnData.attacksReceived?.length) {
       const defeatSource = this.source;
 
       if (defeatSource?.isOnField()) {
-        applyPostVictoryAbAttrs("PostVictoryAbAttr", defeatSource);
+        applyAbAttrs("PostVictoryAbAttr", { pokemon: defeatSource });
         const pvmove = allMoves[pokemon.turnData.attacksReceived[0].move];
         const pvattrs = pvmove.getAttrs("PostVictoryStatStageChangeAttr");
         if (pvattrs.length) {

src/phases/move-effect-phase.ts

@@ -1,12 +1,6 @@
 import { BattlerIndex } from "#enums/battler-index";
 import { globalScene } from "#app/global-scene";
-import {
-  applyExecutedMoveAbAttrs,
-  applyPostAttackAbAttrs,
-  applyPostDamageAbAttrs,
-  applyPostDefendAbAttrs,
-  applyPreAttackAbAttrs,
-} from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { ConditionalProtectTag } from "#app/data/arena-tag";
 import { ArenaTagSide } from "#enums/arena-tag-side";
 import { MoveAnim } from "#app/data/battle-anims";
@@ -322,7 +316,7 @@ export class MoveEffectPhase extends PokemonPhase {
       // Assume single target for multi hit
       applyMoveAttrs("MultiHitAttr", user, this.getFirstTarget() ?? null, move, hitCount);
       // If Parental Bond is applicable, add another hit
-      applyPreAttackAbAttrs("AddSecondStrikeAbAttr", user, null, move, false, hitCount, null);
+      applyAbAttrs("AddSecondStrikeAbAttr", { pokemon: user, move, hitCount });
       // If Multi-Lens is applicable, add hits equal to the number of held Multi-Lenses
       globalScene.applyModifiers(PokemonMultiHitModifier, user.isPlayer(), user, move.id, hitCount);
       // Set the user's relevant turnData fields to reflect the final hit count
@@ -370,7 +364,7 @@ export class MoveEffectPhase extends PokemonPhase {
     // Add to the move history entry
     if (this.firstHit) {
       user.pushMoveHistory(this.moveHistoryEntry);
-      applyExecutedMoveAbAttrs("ExecutedMoveAbAttr", user);
+      applyAbAttrs("ExecutedMoveAbAttr", { pokemon: user });
     }
 
     try {
@@ -439,7 +433,7 @@ export class MoveEffectPhase extends PokemonPhase {
    * @param hitResult - The {@linkcode HitResult} of the attempted move
    */
   protected applyOnGetHitAbEffects(user: Pokemon, target: Pokemon, hitResult: HitResult): void {
-    applyPostDefendAbAttrs("PostDefendAbAttr", target, user, this.move, hitResult);
+    applyAbAttrs("PostDefendAbAttr", { pokemon: target, opponent: user, move: this.move, hitResult });
     target.lapseTags(BattlerTagLapseType.AFTER_HIT);
   }
 
@@ -808,7 +802,9 @@ export class MoveEffectPhase extends PokemonPhase {
 
       // Multi-hit check for Wimp Out/Emergency Exit
       if (user.turnData.hitCount > 1) {
-        applyPostDamageAbAttrs("PostDamageAbAttr", target, 0, target.hasPassive(), false, [], user);
+        // TODO: Investigate why 0 is being passed for damage amount here
+        // and then determing if refactoring `applyMove` to return the damage dealt is appropriate.
+        applyAbAttrs("PostDamageAbAttr", { pokemon: target, damage: 0, source: user });
       }
     }
   }
@@ -1002,7 +998,7 @@ export class MoveEffectPhase extends PokemonPhase {
     this.triggerMoveEffects(MoveEffectTrigger.POST_APPLY, user, target, firstTarget, false);
     this.applyHeldItemFlinchCheck(user, target, dealsDamage);
     this.applyOnGetHitAbEffects(user, target, hitResult);
-    applyPostAttackAbAttrs("PostAttackAbAttr", user, target, this.move, hitResult);
+    applyAbAttrs("PostAttackAbAttr", { pokemon: user, opponent: target, move: this.move, hitResult });
 
     // We assume only enemy Pokemon are able to have the EnemyAttackStatusEffectChanceModifier from tokens
     if (!user.isPlayer() && this.move.is("AttackMove")) {

src/phases/move-end-phase.ts

@@ -2,8 +2,8 @@ import { globalScene } from "#app/global-scene";
 import { BattlerTagLapseType } from "#enums/battler-tag-lapse-type";
 import { PokemonPhase } from "./pokemon-phase";
 import type { BattlerIndex } from "#enums/battler-index";
-import { applyPostSummonAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import type Pokemon from "#app/field/pokemon";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 
 export class MoveEndPhase extends PokemonPhase {
   public readonly phaseName = "MoveEndPhase";
@@ -30,7 +30,7 @@ export class MoveEndPhase extends PokemonPhase {
     globalScene.arena.setIgnoreAbilities(false);
     for (const target of this.targets) {
       if (target) {
-        applyPostSummonAbAttrs("PostSummonRemoveEffectAbAttr", target);
+        applyAbAttrs("PostSummonRemoveEffectAbAttr", { pokemon: target });
       }
     }
 

src/phases/move-phase.ts

@@ -1,6 +1,6 @@
 import { BattlerIndex } from "#enums/battler-index";
 import { globalScene } from "#app/global-scene";
-import { applyAbAttrs, applyPostMoveUsedAbAttrs, applyPreAttackAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import type { DelayedAttackTag } from "#app/data/arena-tag";
 import { CommonAnim } from "#enums/move-anims-common";
 import { CenterOfAttentionTag } from "#app/data/battler-tags";
@@ -228,14 +228,11 @@ export class MovePhase extends BattlePhase {
       case StatusEffect.SLEEP: {
         applyMoveAttrs("BypassSleepAttr", this.pokemon, null, this.move.getMove());
         const turnsRemaining = new NumberHolder(this.pokemon.status.sleepTurnsRemaining ?? 0);
-        applyAbAttrs(
-          "ReduceStatusEffectDurationAbAttr",
-          this.pokemon,
-          null,
-          false,
-          this.pokemon.status.effect,
-          turnsRemaining,
-        );
+        applyAbAttrs("ReduceStatusEffectDurationAbAttr", {
+          pokemon: this.pokemon,
+          statusEffect: this.pokemon.status.effect,
+          duration: turnsRemaining,
+        });
         this.pokemon.status.sleepTurnsRemaining = turnsRemaining.value;
         healed = this.pokemon.status.sleepTurnsRemaining <= 0;
         activated = !healed && !this.pokemon.getTag(BattlerTagType.BYPASS_SLEEP);
@@ -396,7 +393,8 @@ export class MovePhase extends BattlePhase {
      */
     if (success) {
       const move = this.move.getMove();
-      applyPreAttackAbAttrs("PokemonTypeChangeAbAttr", this.pokemon, null, move);
+      // TODO: Investigate whether PokemonTypeChangeAbAttr can drop the "opponent" parameter
+      applyAbAttrs("PokemonTypeChangeAbAttr", { pokemon: this.pokemon, move, opponent: targets[0] });
       globalScene.phaseManager.unshiftNew(
         "MoveEffectPhase",
         this.pokemon.getBattlerIndex(),
@@ -406,7 +404,11 @@ export class MovePhase extends BattlePhase {
       );
     } else {
       if ([MoveId.ROAR, MoveId.WHIRLWIND, MoveId.TRICK_OR_TREAT, MoveId.FORESTS_CURSE].includes(this.move.moveId)) {
-        applyPreAttackAbAttrs("PokemonTypeChangeAbAttr", this.pokemon, null, this.move.getMove());
+        applyAbAttrs("PokemonTypeChangeAbAttr", {
+          pokemon: this.pokemon,
+          move: this.move.getMove(),
+          opponent: targets[0],
+        });
       }
 
       this.pokemon.pushMoveHistory({
@@ -438,7 +440,7 @@ export class MovePhase extends BattlePhase {
     if (this.move.getMove().hasFlag(MoveFlags.DANCE_MOVE) && !dancerModes.includes(this.useMode)) {
       // TODO: Fix in dancer PR to move to MEP for hit checks
       globalScene.getField(true).forEach(pokemon => {
-        applyPostMoveUsedAbAttrs("PostMoveUsedAbAttr", pokemon, this.move, this.pokemon, this.targets);
+        applyAbAttrs("PostMoveUsedAbAttr", { pokemon, move: this.move, source: this.pokemon, targets: this.targets });
       });
     }
   }
@@ -470,7 +472,11 @@ export class MovePhase extends BattlePhase {
     }
 
     // Protean and Libero apply on the charging turn of charge moves
-    applyPreAttackAbAttrs("PokemonTypeChangeAbAttr", this.pokemon, null, this.move.getMove());
+    applyAbAttrs("PokemonTypeChangeAbAttr", {
+      pokemon: this.pokemon,
+      move: this.move.getMove(),
+      opponent: targets[0],
+    });
 
     globalScene.phaseManager.unshiftNew(
       "MoveChargePhase",
@@ -523,7 +529,12 @@ export class MovePhase extends BattlePhase {
         .getField(true)
         .filter(p => p !== this.pokemon)
         .forEach(p =>
-          applyAbAttrs("RedirectMoveAbAttr", p, null, false, this.move.moveId, redirectTarget, this.pokemon),
+          applyAbAttrs("RedirectMoveAbAttr", {
+            pokemon: p,
+            moveId: this.move.moveId,
+            targetIndex: redirectTarget,
+            sourcePokemon: this.pokemon,
+          }),
         );
 
       /** `true` if an Ability is responsible for redirecting the move to another target; `false` otherwise */

src/phases/new-biome-encounter-phase.ts

@@ -14,7 +14,7 @@ export class NewBiomeEncounterPhase extends NextEncounterPhase {
       if (pokemon) {
         pokemon.resetBattleAndWaveData();
         if (pokemon.isOnField()) {
-          applyAbAttrs("PostBiomeChangeAbAttr", pokemon, null);
+          applyAbAttrs("PostBiomeChangeAbAttr", { pokemon });
         }
       }
     }

src/phases/obtain-status-effect-phase.ts

@@ -8,7 +8,7 @@ import type Pokemon from "#app/field/pokemon";
 import { getPokemonNameWithAffix } from "#app/messages";
 import { PokemonPhase } from "./pokemon-phase";
 import { SpeciesFormChangeStatusEffectTrigger } from "#app/data/pokemon-forms/form-change-triggers";
-import { applyPostSetStatusAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { isNullOrUndefined } from "#app/utils/common";
 
 export class ObtainStatusEffectPhase extends PokemonPhase {
@@ -53,7 +53,11 @@ export class ObtainStatusEffectPhase extends PokemonPhase {
             globalScene.triggerPokemonFormChange(pokemon, SpeciesFormChangeStatusEffectTrigger, true);
             // If mold breaker etc was used to set this status, it shouldn't apply to abilities activated afterwards
             globalScene.arena.setIgnoreAbilities(false);
-            applyPostSetStatusAbAttrs("PostSetStatusAbAttr", pokemon, this.statusEffect, this.sourcePokemon);
+            applyAbAttrs("PostSetStatusAbAttr", {
+              pokemon,
+              effect: this.statusEffect,
+              sourcePokemon: this.sourcePokemon ?? undefined,
+            });
           }
           this.end();
         });

src/phases/post-summon-activate-ability-phase.ts

@@ -1,4 +1,4 @@
-import { applyPostSummonAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { PostSummonPhase } from "#app/phases/post-summon-phase";
 import type { BattlerIndex } from "#enums/battler-index";
 
@@ -16,7 +16,8 @@ export class PostSummonActivateAbilityPhase extends PostSummonPhase {
   }
 
   start() {
-    applyPostSummonAbAttrs("PostSummonAbAttr", this.getPokemon(), this.passive, false);
+    // TODO: Check with Dean on whether or not passive must be provided to `this.passive`
+    applyAbAttrs("PostSummonAbAttr", { pokemon: this.getPokemon(), passive: this.passive });
 
     this.end();
   }

src/phases/post-summon-phase.ts

@@ -28,7 +28,7 @@ export class PostSummonPhase extends PokemonPhase {
 
     const field = pokemon.isPlayer() ? globalScene.getPlayerField() : globalScene.getEnemyField();
     for (const p of field) {
-      applyAbAttrs("CommanderAbAttr", p, null, false);
+      applyAbAttrs("CommanderAbAttr", { pokemon: p });
     }
 
     this.end();

src/phases/post-turn-status-effect-phase.ts

@@ -1,6 +1,6 @@
 import { globalScene } from "#app/global-scene";
 import type { BattlerIndex } from "#enums/battler-index";
-import { applyAbAttrs, applyPostDamageAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { CommonBattleAnim } from "#app/data/battle-anims";
 import { CommonAnim } from "#enums/move-anims-common";
 import { getStatusEffectActivationText } from "#app/data/status-effect";
@@ -22,8 +22,8 @@ export class PostTurnStatusEffectPhase extends PokemonPhase {
     if (pokemon?.isActive(true) && pokemon.status && pokemon.status.isPostTurn() && !pokemon.switchOutStatus) {
       pokemon.status.incrementTurn();
       const cancelled = new BooleanHolder(false);
-      applyAbAttrs("BlockNonDirectDamageAbAttr", pokemon, cancelled);
-      applyAbAttrs("BlockStatusDamageAbAttr", pokemon, cancelled);
+      applyAbAttrs("BlockNonDirectDamageAbAttr", { pokemon, cancelled });
+      applyAbAttrs("BlockStatusDamageAbAttr", { pokemon, cancelled });
 
       if (!cancelled.value) {
         globalScene.phaseManager.queueMessage(
@@ -39,14 +39,14 @@ export class PostTurnStatusEffectPhase extends PokemonPhase {
             break;
           case StatusEffect.BURN:
             damage.value = Math.max(pokemon.getMaxHp() >> 4, 1);
-            applyAbAttrs("ReduceBurnDamageAbAttr", pokemon, null, false, damage);
+            applyAbAttrs("ReduceBurnDamageAbAttr", { pokemon, burnDamage: damage });
             break;
         }
         if (damage.value) {
           // Set preventEndure flag to avoid pokemon surviving thanks to focus band, sturdy, endure ...
           globalScene.damageNumberHandler.add(this.getPokemon(), pokemon.damage(damage.value, false, true));
           pokemon.updateInfo();
-          applyPostDamageAbAttrs("PostDamageAbAttr", pokemon, damage.value, pokemon.hasPassive(), false, []);
+          applyAbAttrs("PostDamageAbAttr", { pokemon, damage: damage.value });
         }
         new CommonBattleAnim(CommonAnim.POISON + (pokemon.status.effect - 1), pokemon).play(false, () => this.end());
       } else {

src/phases/quiet-form-change-phase.ts

@@ -181,9 +181,10 @@ export class QuietFormChangePhase extends BattlePhase {
       }
     }
     if (this.formChange.trigger instanceof SpeciesFormChangeTeraTrigger) {
-      applyAbAttrs("PostTeraFormChangeStatChangeAbAttr", this.pokemon, null);
-      applyAbAttrs("ClearWeatherAbAttr", this.pokemon, null);
-      applyAbAttrs("ClearTerrainAbAttr", this.pokemon, null);
+      const params = { pokemon: this.pokemon };
+      applyAbAttrs("PostTeraFormChangeStatChangeAbAttr", params);
+      applyAbAttrs("ClearWeatherAbAttr", params);
+      applyAbAttrs("ClearTerrainAbAttr", params);
     }
 
     super.end();

src/phases/stat-stage-change-phase.ts

@@ -1,10 +1,6 @@
 import { globalScene } from "#app/global-scene";
 import type { BattlerIndex } from "#enums/battler-index";
-import {
-  applyAbAttrs,
-  applyPostStatStageChangeAbAttrs,
-  applyPreStatStageChangeAbAttrs,
-} from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { MistTag } from "#app/data/arena-tag";
 import { ArenaTagSide } from "#enums/arena-tag-side";
 import type { ArenaTag } from "#app/data/arena-tag";
@@ -18,6 +14,10 @@ import { PokemonPhase } from "./pokemon-phase";
 import { Stat, type BattleStat, getStatKey, getStatStageChangeDescriptionKey } from "#enums/stat";
 import { OctolockTag } from "#app/data/battler-tags";
 import { ArenaTagType } from "#app/enums/arena-tag-type";
+import type {
+  ConditionalUserFieldProtectStatAbAttrParams,
+  PreStatStageChangeAbAttrParams,
+} from "#app/@types/ability-types";
 
 export type StatStageChangeCallback = (
   target: Pokemon | null,
@@ -126,7 +126,7 @@ export class StatStageChangePhase extends PokemonPhase {
     const stages = new NumberHolder(this.stages);
 
     if (!this.ignoreAbilities) {
-      applyAbAttrs("StatStageChangeMultiplierAbAttr", pokemon, null, false, stages);
+      applyAbAttrs("StatStageChangeMultiplierAbAttr", { pokemon, numStages: stages });
     }
 
     let simulate = false;
@@ -146,42 +146,38 @@ export class StatStageChangePhase extends PokemonPhase {
       }
 
       if (!cancelled.value && !this.selfTarget && stages.value < 0) {
-        applyPreStatStageChangeAbAttrs("ProtectStatAbAttr", pokemon, stat, cancelled, simulate);
-        applyPreStatStageChangeAbAttrs(
-          "ConditionalUserFieldProtectStatAbAttr",
+        const abAttrParams: PreStatStageChangeAbAttrParams & ConditionalUserFieldProtectStatAbAttrParams = {
           pokemon,
           stat,
           cancelled,
-          simulate,
-          pokemon,
-        );
+          simulated: simulate,
+          target: pokemon,
+          stages: this.stages,
+        };
+        applyAbAttrs("ProtectStatAbAttr", abAttrParams);
+        applyAbAttrs("ConditionalUserFieldProtectStatAbAttr", abAttrParams);
+        // TODO: Consider skipping this call if `cancelled` is false.
         const ally = pokemon.getAlly();
         if (!isNullOrUndefined(ally)) {
-          applyPreStatStageChangeAbAttrs(
-            "ConditionalUserFieldProtectStatAbAttr",
-            ally,
-            stat,
-            cancelled,
-            simulate,
-            pokemon,
-          );
+          applyAbAttrs("ConditionalUserFieldProtectStatAbAttr", { ...abAttrParams, pokemon: ally });
         }
 
         /** Potential stat reflection due to Mirror Armor, does not apply to Octolock end of turn effect */
         if (
           opponentPokemon !== undefined &&
+          // TODO: investigate whether this is stoping mirror armor from applying to non-octolock
+          // reasons for stat drops if the user has the Octolock tag
           !pokemon.findTag(t => t instanceof OctolockTag) &&
           !this.comingFromMirrorArmorUser
         ) {
-          applyPreStatStageChangeAbAttrs(
-            "ReflectStatStageChangeAbAttr",
+          applyAbAttrs("ReflectStatStageChangeAbAttr", {
             pokemon,
             stat,
             cancelled,
-            simulate,
-            opponentPokemon,
-            this.stages,
-          );
+            simulated: simulate,
+            source: opponentPokemon,
+            stages: this.stages,
+          });
         }
       }
 
@@ -222,17 +218,16 @@ export class StatStageChangePhase extends PokemonPhase {
 
       if (stages.value > 0 && this.canBeCopied) {
         for (const opponent of pokemon.getOpponents()) {
-          applyAbAttrs("StatStageChangeCopyAbAttr", opponent, null, false, this.stats, stages.value);
+          applyAbAttrs("StatStageChangeCopyAbAttr", { pokemon: opponent, stats: this.stats, numStages: stages.value });
         }
       }
 
-      applyPostStatStageChangeAbAttrs(
-        "PostStatStageChangeAbAttr",
+      applyAbAttrs("PostStatStageChangeAbAttr", {
         pokemon,
-        filteredStats,
-        this.stages,
-        this.selfTarget,
-      );
+        stats: filteredStats,
+        stages: this.stages,
+        selfTarget: this.selfTarget,
+      });
 
       // Look for any other stat change phases; if this is the last one, do White Herb check
       const existingPhase = globalScene.phaseManager.findPhase(

src/phases/summon-phase.ts

@@ -10,7 +10,7 @@ import { getPokemonNameWithAffix } from "#app/messages";
 import i18next from "i18next";
 import { PartyMemberPokemonPhase } from "./party-member-pokemon-phase";
 import { MysteryEncounterMode } from "#enums/mystery-encounter-mode";
-import { applyPreSummonAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { globalScene } from "#app/global-scene";
 
 export class SummonPhase extends PartyMemberPokemonPhase {
@@ -27,7 +27,7 @@ export class SummonPhase extends PartyMemberPokemonPhase {
   start() {
     super.start();
 
-    applyPreSummonAbAttrs("PreSummonAbAttr", this.getPokemon());
+    applyAbAttrs("PreSummonAbAttr", { pokemon: this.getPokemon() });
     this.preSummon();
   }
 

src/phases/switch-summon-phase.ts

@@ -1,5 +1,5 @@
 import { globalScene } from "#app/global-scene";
-import { applyPreSummonAbAttrs, applyPreSwitchOutAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { allMoves } from "#app/data/data-lists";
 import { getPokeballTintColor } from "#app/data/pokeball";
 import { SpeciesFormChangeActiveTrigger } from "#app/data/pokemon-forms/form-change-triggers";
@@ -124,8 +124,8 @@ export class SwitchSummonPhase extends SummonPhase {
     switchedInPokemon.resetSummonData();
     switchedInPokemon.loadAssets(true);
 
-    applyPreSummonAbAttrs("PreSummonAbAttr", switchedInPokemon);
-    applyPreSwitchOutAbAttrs("PreSwitchOutAbAttr", this.lastPokemon);
+    applyAbAttrs("PreSummonAbAttr", { pokemon: switchedInPokemon });
+    applyAbAttrs("PreSwitchOutAbAttr", { pokemon: this.lastPokemon });
     if (!switchedInPokemon) {
       this.end();
       return;

src/phases/turn-end-phase.ts

@@ -1,4 +1,4 @@
-import { applyPostTurnAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { BattlerTagLapseType } from "#enums/battler-tag-lapse-type";
 import { TerrainType } from "#app/data/terrain";
 import { WeatherType } from "#app/enums/weather-type";
@@ -49,7 +49,7 @@ export class TurnEndPhase extends FieldPhase {
           globalScene.applyModifier(EnemyStatusEffectHealChanceModifier, false, pokemon);
         }
 
-        applyPostTurnAbAttrs("PostTurnAbAttr", pokemon);
+        applyAbAttrs("PostTurnAbAttr", { pokemon });
       }
 
       globalScene.applyModifiers(TurnStatusEffectModifier, pokemon.isPlayer(), pokemon);

src/phases/turn-start-phase.ts

@@ -66,8 +66,12 @@ export class TurnStartPhase extends FieldPhase {
     globalScene.getField(true).forEach(p => {
       const bypassSpeed = new BooleanHolder(false);
       const canCheckHeldItems = new BooleanHolder(true);
-      applyAbAttrs("BypassSpeedChanceAbAttr", p, null, false, bypassSpeed);
-      applyAbAttrs("PreventBypassSpeedChanceAbAttr", p, null, false, bypassSpeed, canCheckHeldItems);
+      applyAbAttrs("BypassSpeedChanceAbAttr", { pokemon: p, bypass: bypassSpeed });
+      applyAbAttrs("PreventBypassSpeedChanceAbAttr", {
+        pokemon: p,
+        bypass: bypassSpeed,
+        canCheckHeldItems: canCheckHeldItems,
+      });
       if (canCheckHeldItems.value) {
         globalScene.applyModifiers(BypassSpeedChanceModifier, p.isPlayer(), p, bypassSpeed);
       }

src/phases/weather-effect-phase.ts

@@ -1,9 +1,5 @@
 import { globalScene } from "#app/global-scene";
-import {
-  applyPreWeatherEffectAbAttrs,
-  applyAbAttrs,
-  applyPostWeatherLapseAbAttrs,
-} from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { CommonAnim } from "#enums/move-anims-common";
 import type { Weather } from "#app/data/weather";
 import { getWeatherDamageMessage, getWeatherLapseMessage } from "#app/data/weather";
@@ -41,15 +37,15 @@ export class WeatherEffectPhase extends CommonAnimPhase {
       const cancelled = new BooleanHolder(false);
 
       this.executeForAll((pokemon: Pokemon) =>
-        applyPreWeatherEffectAbAttrs("SuppressWeatherEffectAbAttr", pokemon, this.weather, cancelled),
+        applyAbAttrs("SuppressWeatherEffectAbAttr", { pokemon, weather: this.weather, cancelled }),
       );
 
       if (!cancelled.value) {
         const inflictDamage = (pokemon: Pokemon) => {
           const cancelled = new BooleanHolder(false);
 
-          applyPreWeatherEffectAbAttrs("PreWeatherDamageAbAttr", pokemon, this.weather, cancelled);
-          applyAbAttrs("BlockNonDirectDamageAbAttr", pokemon, cancelled);
+          applyAbAttrs("PreWeatherDamageAbAttr", { pokemon, weather: this.weather, cancelled });
+          applyAbAttrs("BlockNonDirectDamageAbAttr", { pokemon, cancelled });
 
           if (
             cancelled.value ||
@@ -80,7 +76,7 @@ export class WeatherEffectPhase extends CommonAnimPhase {
     globalScene.ui.showText(getWeatherLapseMessage(this.weather.weatherType) ?? "", null, () => {
       this.executeForAll((pokemon: Pokemon) => {
         if (!pokemon.switchOutStatus) {
-          applyPostWeatherLapseAbAttrs("PostWeatherLapseAbAttr", pokemon, this.weather);
+          applyAbAttrs("PostWeatherLapseAbAttr", { pokemon, weather: this.weather });
         }
       });
 

test/abilities/cud_chew.test.ts

@@ -1,4 +1,4 @@
-import { RepeatBerryNextTurnAbAttr } from "#app/data/abilities/ability";
+import { CudChewConsumeBerryAbAttr } from "#app/data/abilities/ability";
 import Pokemon from "#app/field/pokemon";
 import { globalScene } from "#app/global-scene";
 import { getPokemonNameWithAffix } from "#app/messages";
@@ -196,7 +196,7 @@ describe("Abilities - Cud Chew", () => {
 
   describe("regurgiates berries", () => {
     it("re-triggers effects on eater without pushing to array", async () => {
-      const apply = vi.spyOn(RepeatBerryNextTurnAbAttr.prototype, "apply");
+      const apply = vi.spyOn(CudChewConsumeBerryAbAttr.prototype, "apply");
       await game.classicMode.startBattle([SpeciesId.FARIGIRAF]);
 
       const farigiraf = game.scene.getPlayerPokemon()!;

test/abilities/harvest.test.ts

@@ -95,7 +95,7 @@ describe("Abilities - Harvest", () => {
 
     // Give ourselves harvest and disable enemy neut gas,
     // but force our roll to fail so we don't accidentally recover anything
-    vi.spyOn(PostTurnRestoreBerryAbAttr.prototype, "canApplyPostTurn").mockReturnValueOnce(false);
+    vi.spyOn(PostTurnRestoreBerryAbAttr.prototype, "canApply").mockReturnValueOnce(false);
     game.override.ability(AbilityId.HARVEST);
     game.move.select(MoveId.GASTRO_ACID);
     await game.move.selectEnemyMove(MoveId.NUZZLE);

test/abilities/healer.test.ts

@@ -42,7 +42,7 @@ describe("Abilities - Healer", () => {
   });
 
   it("should not queue a message phase for healing if the ally has fainted", async () => {
-    const abSpy = vi.spyOn(PostTurnResetStatusAbAttr.prototype, "canApplyPostTurn");
+    const abSpy = vi.spyOn(PostTurnResetStatusAbAttr.prototype, "canApply");
     game.override.moveset([MoveId.SPLASH, MoveId.LUNAR_DANCE]);
     await game.classicMode.startBattle([SpeciesId.MAGIKARP, SpeciesId.MAGIKARP]);
 

test/abilities/moody.test.ts

@@ -68,7 +68,7 @@ describe("Abilities - Moody", () => {
   });
 
   it("should only decrease one stat stage by 1 stage if all stat stages are at 6", async () => {
-    await game.classicMode.startBattle();
+    await game.classicMode.startBattle([SpeciesId.MAGIKARP]);
 
     const playerPokemon = game.scene.getPlayerPokemon()!;
 

test/abilities/neutralizing_gas.test.ts

@@ -178,7 +178,7 @@ describe("Abilities - Neutralizing Gas", () => {
 
     const enemy = game.scene.getEnemyPokemon()!;
     const weatherChangeAttr = enemy.getAbilityAttrs("PostSummonWeatherChangeAbAttr", false)[0];
-    vi.spyOn(weatherChangeAttr, "applyPostSummon");
+    const weatherChangeSpy = vi.spyOn(weatherChangeAttr, "apply");
 
     expect(game.scene.arena.getTag(ArenaTagType.NEUTRALIZING_GAS)).toBeDefined();
 
@@ -187,6 +187,6 @@ describe("Abilities - Neutralizing Gas", () => {
     await game.killPokemon(game.scene.getPlayerPokemon()!);
 
     expect(game.scene.arena.getTag(ArenaTagType.NEUTRALIZING_GAS)).toBeUndefined();
-    expect(weatherChangeAttr.applyPostSummon).not.toHaveBeenCalled();
+    expect(weatherChangeSpy).not.toHaveBeenCalled();
   });
 });

test/abilities/sand_veil.test.ts

@@ -1,3 +1,4 @@
+import type { StatMultiplierAbAttrParams } from "#app/@types/ability-types";
 import { allAbilities } from "#app/data/data-lists";
 import { CommandPhase } from "#app/phases/command-phase";
 import { MoveEffectPhase } from "#app/phases/move-effect-phase";
@@ -46,15 +47,13 @@ describe("Abilities - Sand Veil", () => {
     vi.spyOn(leadPokemon[0], "getAbility").mockReturnValue(allAbilities[AbilityId.SAND_VEIL]);
 
     const sandVeilAttr = allAbilities[AbilityId.SAND_VEIL].getAttrs("StatMultiplierAbAttr")[0];
-    vi.spyOn(sandVeilAttr, "applyStatStage").mockImplementation(
-      (_pokemon, _passive, _simulated, stat, statValue, _args) => {
-        if (stat === Stat.EVA && game.scene.arena.weather?.weatherType === WeatherType.SANDSTORM) {
-          statValue.value *= -1; // will make all attacks miss
-          return true;
-        }
-        return false;
-      },
-    );
+    vi.spyOn(sandVeilAttr, "apply").mockImplementation(({ stat, statVal }: StatMultiplierAbAttrParams) => {
+      if (stat === Stat.EVA && game.scene.arena.weather?.weatherType === WeatherType.SANDSTORM) {
+        statVal.value *= -1; // will make all attacks miss
+        return true;
+      }
+      return false;
+    });
 
     expect(leadPokemon[0].hasAbility(AbilityId.SAND_VEIL)).toBe(true);
     expect(leadPokemon[1].hasAbility(AbilityId.SAND_VEIL)).toBe(false);

test/abilities/shield_dust.test.ts

@@ -1,5 +1,5 @@
 import { BattlerIndex } from "#enums/battler-index";
-import { applyAbAttrs, applyPreDefendAbAttrs } from "#app/data/abilities/apply-ab-attrs";
+import { applyAbAttrs } from "#app/data/abilities/apply-ab-attrs";
 import { MoveEffectPhase } from "#app/phases/move-effect-phase";
 import { NumberHolder } from "#app/utils/common";
 import { AbilityId } from "#enums/ability-id";
@@ -52,25 +52,16 @@ describe("Abilities - Shield Dust", () => {
     expect(move.id).toBe(MoveId.AIR_SLASH);
 
     const chance = new NumberHolder(move.chance);
-    await applyAbAttrs(
-      "MoveEffectChanceMultiplierAbAttr",
-      phase.getUserPokemon()!,
-      null,
-      false,
+    applyAbAttrs("MoveEffectChanceMultiplierAbAttr", {
+      pokemon: phase.getUserPokemon()!,
       chance,
       move,
-      phase.getFirstTarget(),
-      false,
-    );
-    await applyPreDefendAbAttrs(
-      "IgnoreMoveEffectsAbAttr",
-      phase.getFirstTarget()!,
-      phase.getUserPokemon()!,
-      null,
-      null,
-      false,
+    });
+    applyAbAttrs("IgnoreMoveEffectsAbAttr", {
+      pokemon: phase.getFirstTarget()!,
+      move,
       chance,
-    );
+    });
     expect(chance.value).toBe(0);
   });
 

test/abilities/unburden.test.ts

@@ -277,7 +277,7 @@ describe("Abilities - Unburden", () => {
     const initialTreeckoSpeed = treecko.getStat(Stat.SPD);
     const initialPurrloinSpeed = purrloin.getStat(Stat.SPD);
     const unburdenAttr = treecko.getAbilityAttrs("PostItemLostAbAttr")[0];
-    vi.spyOn(unburdenAttr, "applyPostItemLost");
+    vi.spyOn(unburdenAttr, "apply");
 
     // Player uses Baton Pass, which also passes the Baton item
     game.move.select(MoveId.BATON_PASS);
@@ -288,7 +288,7 @@ describe("Abilities - Unburden", () => {
     expect(getHeldItemCount(purrloin)).toBe(1);
     expect(treecko.getEffectiveStat(Stat.SPD)).toBe(initialTreeckoSpeed);
     expect(purrloin.getEffectiveStat(Stat.SPD)).toBe(initialPurrloinSpeed);
-    expect(unburdenAttr.applyPostItemLost).not.toHaveBeenCalled();
+    expect(unburdenAttr.apply).not.toHaveBeenCalled();
   });
 
   it("should not speed up a Pokemon after it loses the ability Unburden", async () => {

test/field/pokemon.test.ts

@@ -31,7 +31,7 @@ describe("Spec - Pokemon", () => {
     const pkm = game.scene.getPlayerPokemon()!;
     expect(pkm).toBeDefined();
 
-    expect(pkm.trySetStatus(undefined)).toBe(true);
+    expect(pkm.trySetStatus(undefined)).toBe(false);
   });
 
   describe("Add To Party", () => {

test/moves/safeguard.test.ts

@@ -140,9 +140,8 @@ describe("Moves - Safeguard", () => {
     game.field.mockAbility(player, AbilityId.STATIC);
     vi.spyOn(
       allAbilities[AbilityId.STATIC].getAttrs("PostDefendContactApplyStatusEffectAbAttr")[0],
-      "chance",
-      "get",
-    ).mockReturnValue(100);
+      "canApply",
+    ).mockReturnValue(true);
 
     game.move.select(MoveId.SPLASH);
     await game.move.forceEnemyMove(MoveId.SAFEGUARD);