[Ability] Implement Wimp Out and Emergency Exit

src/data/ability.ts

@@ -1,4 +1,4 @@
-import Pokemon, { HitResult, PlayerPokemon, PokemonMove } from "../field/pokemon";
+import Pokemon, { EnemyPokemon, HitResult, MoveResult, PlayerPokemon, PokemonMove } from "../field/pokemon";
 import { Type } from "./type";
 import { Constructor } from "#app/utils";
 import * as Utils from "../utils";
@@ -9,15 +9,15 @@ import { StatusEffect, getNonVolatileStatusEffects, getStatusEffectDescriptor, g
 import { Gender } from "./gender";
 import Move, { AttackMove, MoveCategory, MoveFlags, MoveTarget, FlinchAttr, OneHitKOAttr, HitHealAttr, allMoves, StatusMove, SelfStatusMove, VariablePowerAttr, applyMoveAttrs, IncrementMovePriorityAttr, VariableMoveTypeAttr, RandomMovesetMoveAttr, RandomMoveAttr, NaturePowerAttr, CopyMoveAttr, MoveAttr, MultiHitAttr, SacrificialAttr, SacrificialAttrOnHit, NeutralDamageAgainstFlyingTypeMultiplierAttr, FixedDamageAttr } from "./move";
 import { ArenaTagSide, ArenaTrapTag } from "./arena-tag";
-import { BerryModifier, PokemonHeldItemModifier } from "../modifier/modifier";
+import { BerryModifier, HitHealModifier, PokemonHeldItemModifier } from "../modifier/modifier";
 import { TerrainType } from "./terrain";
 import { SpeciesFormChangeManualTrigger, SpeciesFormChangeRevertWeatherFormTrigger, SpeciesFormChangeWeatherTrigger } from "./pokemon-forms";
 import i18next from "i18next";
 import { Localizable } from "#app/interfaces/locales";
 import { Command } from "../ui/command-ui-handler";
 import { BerryModifierType } from "#app/modifier/modifier-type";
 import { getPokeballName } from "./pokeball";
-import { BattlerIndex } from "#app/battle";
+import { BattlerIndex, BattleType } from "#app/battle";
 import { Abilities } from "#enums/abilities";
 import { ArenaTagType } from "#enums/arena-tag-type";
 import { BattlerTagType } from "#enums/battler-tag-type";
@@ -29,6 +29,12 @@ import { PokemonHealPhase } from "#app/phases/pokemon-heal-phase";
 import { ShowAbilityPhase } from "#app/phases/show-ability-phase";
 import { StatStageChangePhase } from "#app/phases/stat-stage-change-phase";
 import BattleScene from "#app/battle-scene";
+import { SwitchType } from "#app/enums/switch-type";
+import { SwitchPhase } from "#app/phases/switch-phase";
+import { SwitchSummonPhase } from "#app/phases/switch-summon-phase";
+import { BattleEndPhase } from "#app/phases/battle-end-phase";
+import { NewBattlePhase } from "#app/phases/new-battle-phase";
+import { MoveEndPhase } from "#app/phases/move-end-phase";
 
 export class Ability implements Localizable {
   public id: Abilities;
@@ -3092,7 +3098,7 @@ export class SuppressWeatherEffectAbAttr extends PreWeatherEffectAbAttr {
 /**
  * Condition function to applied to abilities related to Sheer Force.
  * Checks if last move used against target was affected by a Sheer Force user and:
- * Disables: Color Change, Pickpocket, Wimp Out, Emergency Exit, Berserk, Anger Shell
+ * Disables: Color Change, Pickpocket, Berserk, Anger Shell
  * @returns {AbAttrCondition} If false disables the ability which the condition is applied to.
  */
 function getSheerForceHitDisableAbCondition(): AbAttrCondition {
@@ -4833,6 +4839,239 @@ async function applyAbAttrsInternal<TAttr extends AbAttr>(
   }
 }
 
+class ForceSwitchOutHelper {
+  constructor(private switchType: SwitchType) {}
+
+  /**
+   * Handles the logic for switching out a Pokémon based on battle conditions, HP, and the switch type.
+   *
+   * @param pokemon The {@linkcode Pokemon} attempting to switch out.
+   * @returns `true` if the switch is successful
+   */
+  public switchOutLogic(pokemon: Pokemon): boolean {
+    const switchOutTarget = pokemon;
+    /**
+     * If the switch-out target is a player-controlled Pokémon, the function checks:
+     * - Whether there are available party members to switch in.
+     * - If the Pokémon is still alive (hp > 0), and if so, it leaves the field and a new SwitchPhase is initiated.
+     */
+    if (switchOutTarget instanceof PlayerPokemon) {
+      if (switchOutTarget.scene.getParty().filter((p) => p.isAllowedInBattle() && !p.isOnField()).length < 1) {
+        return false;
+      }
+
+      if (switchOutTarget.hp > 0) {
+        switchOutTarget.leaveField(this.switchType === SwitchType.SWITCH);
+        pokemon.scene.prependToPhase(new SwitchPhase(pokemon.scene, this.switchType, switchOutTarget.getFieldIndex(), true, true), MoveEndPhase);
+        return true;
+      }
+    /**
+     * For non-wild battles, it checks if the opposing party has any available Pokémon to switch in.
+     * If yes, the Pokémon leaves the field and a new SwitchSummonPhase is initiated.
+     */
+    } else if (pokemon.scene.currentBattle.battleType !== BattleType.WILD) {
+      if (switchOutTarget.scene.getEnemyParty().filter((p) => p.isAllowedInBattle() && !p.isOnField()).length < 1) {
+        return false;
+      }
+      if (switchOutTarget.hp > 0) {
+        switchOutTarget.leaveField(this.switchType === SwitchType.SWITCH);
+        pokemon.scene.prependToPhase(new SwitchSummonPhase(pokemon.scene, this.switchType, switchOutTarget.getFieldIndex(),
+          (pokemon.scene.currentBattle.trainer ? pokemon.scene.currentBattle.trainer.getNextSummonIndex((switchOutTarget as EnemyPokemon).trainerSlot) : 0),
+          false, false), MoveEndPhase);
+        return true;
+      }
+    /**
+     * For wild Pokémon battles, the Pokémon will flee if the conditions are met (waveIndex and double battles).
+     */
+    } else {
+      if (!pokemon.scene.currentBattle.waveIndex && pokemon.scene.currentBattle.waveIndex % 10 === 0) {
+        return false;
+      }
+
+      if (switchOutTarget.hp > 0) {
+        switchOutTarget.leaveField(false);
+        pokemon.scene.queueMessage(i18next.t("moveTriggers:fled", { pokemonName: getPokemonNameWithAffix(switchOutTarget) }), null, true, 500);
+
+        if (switchOutTarget.scene.currentBattle.double) {
+          const allyPokemon = switchOutTarget.getAlly();
+          switchOutTarget.scene.redirectPokemonMoves(switchOutTarget, allyPokemon);
+        }
+      }
+
+      if (!switchOutTarget.getAlly()?.isActive(true)) {
+        pokemon.scene.clearEnemyHeldItemModifiers();
+
+        if (switchOutTarget.hp) {
+          pokemon.scene.pushPhase(new BattleEndPhase(pokemon.scene));
+          pokemon.scene.pushPhase(new NewBattlePhase(pokemon.scene));
+        }
+      }
+    }
+    return false;
+  }
+
+  /**
+   * Determines if a Pokémon can switch out based on its status, the opponent's status, and battle conditions.
+   *
+   * @param pokemon The Pokémon attempting to switch out.
+   * @param opponent The opponent Pokémon.
+   * @returns `true` if the switch-out condition is met
+   */
+  public getSwitchOutCondition(pokemon: Pokemon, opponent: Pokemon): boolean {
+    const switchOutTarget = pokemon;
+    const player = switchOutTarget instanceof PlayerPokemon;
+
+    if (player) {
+      const blockedByAbility = new Utils.BooleanHolder(false);
+      applyAbAttrs(ForceSwitchOutImmunityAbAttr, opponent, blockedByAbility);
+      return !blockedByAbility.value;
+    }
+
+    if (!player && pokemon.scene.currentBattle.battleType === BattleType.WILD) {
+      if (!pokemon.scene.currentBattle.waveIndex && pokemon.scene.currentBattle.waveIndex % 10 === 0) {
+        return false;
+      }
+    }
+
+    if (!player && pokemon.scene.currentBattle.isBattleMysteryEncounter() && !pokemon.scene.currentBattle.mysteryEncounter?.fleeAllowed) {
+      return false;
+    }
+
+    const party = player ? pokemon.scene.getParty() : pokemon.scene.getEnemyParty();
+    return (!player && pokemon.scene.currentBattle.battleType === BattleType.WILD)
+      || party.filter(p => p.isAllowedInBattle()
+        && (player || (p as EnemyPokemon).trainerSlot === (switchOutTarget as EnemyPokemon).trainerSlot)).length > pokemon.scene.currentBattle.getBattlerCount();
+  }
+
+  /**
+   * Returns a message if the switch-out attempt fails due to ability effects.
+   *
+   * @param target The target Pokémon.
+   * @returns The failure message, or `null` if no failure.
+   */
+  public getFailedText(target: Pokemon): string | null {
+    const blockedByAbility = new Utils.BooleanHolder(false);
+    applyAbAttrs(ForceSwitchOutImmunityAbAttr, target, blockedByAbility);
+    return blockedByAbility.value ? i18next.t("moveTriggers:cannotBeSwitchedOut", { pokemonName: getPokemonNameWithAffix(target) }) : null;
+  }
+}
+
+/**
+ * Calculates the amount of recovery from the Shell Bell item.
+ *
+ * If the Pokémon is holding a Shell Bell, this function computes the amount of health
+ * recovered based on the damage dealt in the current turn. The recovery is multiplied by the
+ * Shell Bell's modifier (if any).
+ *
+ * @param pokemon - The Pokémon whose Shell Bell recovery is being calculated.
+ * @returns The amount of health recovered by Shell Bell.
+ */
+function calculateShellBellRecovery(pokemon: Pokemon): number {
+  const shellBellModifier = pokemon.getHeldItems().find(m => m instanceof HitHealModifier);
+  if (shellBellModifier) {
+    return Utils.toDmgValue(pokemon.turnData.damageDealt / 8) * shellBellModifier.stackCount;
+  }
+  return 0;
+}
+
+/**
+ * Triggers after the Pokemon takes any damage
+ * @extends AbAttr
+ */
+export class PostDamageAbAttr extends AbAttr {
+  public applyPostDamage(pokemon: Pokemon, damage: number, passive: boolean, simulated: boolean, args: any[], source?: Pokemon): boolean | Promise<boolean> {
+    return false;
+  }
+}
+
+/**
+ * Ability attribute for forcing a Pokémon to switch out after its health drops below half.
+ * This attribute checks various conditions related to the damage received, the moves used by the Pokémon
+ * and its opponents, and determines whether a forced switch-out should occur.
+ *
+ * Used by Wimp Out and Emergency Exit
+ *
+ * @extends PostDamageAbAttr
+ * @see {@linkcode applyPostDamage}
+ */
+export class PostDamageForceSwitchAbAttr extends PostDamageAbAttr {
+  private helper: ForceSwitchOutHelper = new ForceSwitchOutHelper(SwitchType.SWITCH);
+  private hpRatio: number;
+
+  constructor(hpRatio: number = 0.5) {
+    super();
+    this.hpRatio = hpRatio;
+  }
+
+  /**
+   * Applies the switch-out logic after the Pokémon takes damage.
+   * Checks various conditions based on the moves used by the Pokémon, the opponents' moves, and
+   * the Pokémon's health after damage to determine whether the switch-out should occur.
+   *
+   * @param pokemon The Pokémon that took damage.
+   * @param damage The amount of damage taken by the Pokémon.
+   * @param passive N/A
+   * @param simulated Whether the ability is being simulated.
+   * @param args N/A
+   * @param source The Pokemon that dealt damage
+   * @returns `true` if the switch-out logic was successfully applied
+   */
+  public override applyPostDamage(pokemon: Pokemon, damage: number, passive: boolean, simulated: boolean, args: any[], source?: Pokemon): boolean | Promise<boolean> {
+    const moveHistory = pokemon.getMoveHistory();
+    // Will not activate when the Pokémon's HP is lowered by cutting its own HP
+    const fordbiddenAttackingMoves = [ Moves.BELLY_DRUM, Moves.SUBSTITUTE, Moves.CURSE, Moves.PAIN_SPLIT ];
+    if (moveHistory.length > 0) {
+      const lastMoveUsed = moveHistory[moveHistory.length - 1];
+      if (fordbiddenAttackingMoves.includes(lastMoveUsed.move)) {
+        return false;
+      }
+    }
+
+    // Dragon Tail and Circle Throw switch out Pokémon before the Ability activates.
+    const fordbiddenDefendingMoves = [ Moves.DRAGON_TAIL, Moves.CIRCLE_THROW ];
+    if (source) {
+      const enemyMoveHistory = source.getMoveHistory();
+      if (enemyMoveHistory.length > 0) {
+        const enemyLastMoveUsed = enemyMoveHistory[enemyMoveHistory.length - 1];
+        // Will not activate if the Pokémon's HP falls below half while it is in the air during Sky Drop.
+        if (fordbiddenDefendingMoves.includes(enemyLastMoveUsed.move) || enemyLastMoveUsed.move === Moves.SKY_DROP && enemyLastMoveUsed.result === MoveResult.OTHER) {
+          return false;
+        // Will not activate if the Pokémon's HP falls below half by a move affected by Sheer Force.
+        } else if (allMoves[enemyLastMoveUsed.move].chance >= 0 && source.hasAbility(Abilities.SHEER_FORCE)) {
+          return false;
+        // Activate only after the last hit of multistrike moves
+        } else if (source.turnData.hitsLeft > 1) {
+          return false;
+        }
+        if (source.turnData.hitCount > 1) {
+          damage = pokemon.turnData.damageTaken;
+        }
+      }
+    }
+
+    if (pokemon.hp + damage >= pokemon.getMaxHp() * this.hpRatio) {
+      // Activates if it falls below half and recovers back above half from a Shell Bell
+      const shellBellHeal = calculateShellBellRecovery(pokemon);
+      if (pokemon.hp - shellBellHeal < pokemon.getMaxHp() * this.hpRatio) {
+        for (const opponent of pokemon.getOpponents()) {
+          if (!this.helper.getSwitchOutCondition(pokemon, opponent)) {
+            return false;
+          }
+        }
+        return this.helper.switchOutLogic(pokemon);
+      } else {
+        return false;
+      }
+    } else {
+      return false;
+    }
+  }
+  public getFailedText(user: Pokemon, target: Pokemon, move: Move, cancelled: Utils.BooleanHolder): string | null {
+    return this.helper.getFailedText(target);
+  }
+}
+
+
 export function applyAbAttrs(attrType: Constructor<AbAttr>, pokemon: Pokemon, cancelled: Utils.BooleanHolder | null, simulated: boolean = false, ...args: any[]): Promise<void> {
   return applyAbAttrsInternal<AbAttr>(attrType, pokemon, (attr, passive) => attr.apply(pokemon, passive, simulated, cancelled, args), args, false, simulated);
 }
@@ -4866,6 +5105,11 @@ export function applyPostSetStatusAbAttrs(attrType: Constructor<PostSetStatusAbA
   return applyAbAttrsInternal<PostSetStatusAbAttr>(attrType, pokemon, (attr, passive) => attr.applyPostSetStatus(pokemon, sourcePokemon, passive, effect, simulated, args), args, false, simulated);
 }
 
+export function applyPostDamageAbAttrs(attrType: Constructor<PostDamageAbAttr>,
+  pokemon: Pokemon, damage: number, passive: boolean, simulated: boolean = false, args: any[], source?: Pokemon): Promise<void> {
+  return applyAbAttrsInternal<PostDamageAbAttr>(attrType, pokemon, (attr, passive) => attr.applyPostDamage(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
@@ -5607,11 +5851,11 @@ export function initAbilities() {
     new Ability(Abilities.STAMINA, 7)
       .attr(PostDefendStatStageChangeAbAttr, (target, user, move) => move.category !== MoveCategory.STATUS, Stat.DEF, 1),
     new Ability(Abilities.WIMP_OUT, 7)
-      .condition(getSheerForceHitDisableAbCondition())
-      .unimplemented(),
+      .attr(PostDamageForceSwitchAbAttr)
+      .edgeCase(), // Should not trigger when hurting itself in confusion
     new Ability(Abilities.EMERGENCY_EXIT, 7)
-      .condition(getSheerForceHitDisableAbCondition())
-      .unimplemented(),
+      .attr(PostDamageForceSwitchAbAttr)
+      .edgeCase(), // Should not trigger when hurting itself in confusion
     new Ability(Abilities.WATER_COMPACTION, 7)
       .attr(PostDefendStatStageChangeAbAttr, (target, user, move) => user.getMoveType(move) === Type.WATER && move.category !== MoveCategory.STATUS, Stat.DEF, 2),
     new Ability(Abilities.MERCILESS, 7)