Added move condition to Transform + fixed up imposter target selection

src/data/abilities/ability.ts

@@ -75,7 +75,7 @@ import type {
   AbAttrString,
   AbAttrMap,
 } from "#app/@types/ability-types";
-import type { BattlerIndex } from "#enums/battler-index";
+import { BattlerIndex } from "#enums/battler-index";
 import type Move from "#app/data/moves/move";
 import type { ArenaTrapTag, SuppressAbilitiesTag } from "#app/data/arena-tag";
 import type { Constructor } from "#app/utils/common";
@@ -3870,60 +3870,39 @@ export class PostSummonCopyAllyStatsAbAttr extends PostSummonAbAttr {
  * Attribute used by {@linkcode AbilityId.IMPOSTER} to transform into a random opposing pokemon on entry.
  */
 export class PostSummonTransformAbAttr extends PostSummonAbAttr {
+  private targetIndex: BattlerIndex = BattlerIndex.ATTACKER;
   constructor() {
     super(true, false);
   }
 
-  private getTarget(targets: Pokemon[]): Pokemon {
+  /**
-    let target: Pokemon = targets[0];
+   * Return the correct opponent for Imposter to copy, barring enemies with fusions, substitutes and illusions.
-    if (targets.length > 1) {
+   * @param user - The {@linkcode Pokemon} with this ability.
-      globalScene.executeWithSeedOffset(() => {
+   * @returns The {@linkcode Pokemon} to transform into, or `undefined` if none are eligible.
-        // in a double battle, if one of the opposing pokemon is fused the other one will be chosen
+   * @remarks
-        // if both are fused, then Imposter will fail below
+   * This sets the private `targetIndex` field to the target's {@linkcode BattlerIndex} on success.
-        if (targets[0].fusionSpecies) {
+   */
-          target = targets[1];
+  private getTarget(user: Pokemon): Pokemon | undefined {
-          return;
+    // As opposed to the mainline behavior of "always copy the opposite slot",
-        }
+    // PKR Imposter instead attempts to copy a random eligible opposing Pokemon meeting Transform's criteria.
-        if (targets[1].fusionSpecies) {
+    // If none are eligible to copy, it will not activate.
-          target = targets[0];
+    const targets = user.getOpponents().filter(opp => user.canTransformInto(opp));
-          return;
+    if (targets.length === 0) {
-        }
+      return undefined;
-        target = randSeedItem(targets);
-      }, globalScene.currentBattle.waveIndex);
-    } else {
-      target = targets[0];
     }
 
-    target = target!;
+    const mon = targets[user.randBattleSeedInt(targets.length)];
-
+    this.targetIndex = mon.getBattlerIndex();
-    return target;
+    return mon;
   }
 
-  override canApplyPostSummon(pokemon: Pokemon, _passive: boolean, simulated: boolean, _args: any[]): boolean {
+  override canApplyPostSummon(pokemon: Pokemon, _passive: boolean, _simulated: boolean, _args: any[]): boolean {
-    const targets = pokemon.getOpponents();
+    const target = this.getTarget(pokemon);
-    const target = this.getTarget(targets);
+    return !!target;
-
-    if (target?.summonData?.illusion || pokemon?.isTransformed() || target?.isTransformed()) {
-      return false;
-    }
-
-    if (simulated || !targets.length) {
-      return simulated;
-    }
-
-    // transforming from or into fusion pokemon causes various problems (including crashes and save corruption)
-    return !(this.getTarget(targets).fusionSpecies || pokemon.fusionSpecies);
   }
 
   override applyPostSummon(pokemon: Pokemon, _passive: boolean, _simulated: boolean, _args: any[]): void {
-    const target = this.getTarget(pokemon.getOpponents());
+    globalScene.phaseManager.unshiftNew("PokemonTransformPhase", pokemon.getBattlerIndex(), this.targetIndex, true);
-
-    globalScene.phaseManager.unshiftNew(
-      "PokemonTransformPhase",
-      pokemon.getBattlerIndex(),
-      target.getBattlerIndex(),
-      true,
-    );
   }
 }
 
@@ -3997,7 +3976,7 @@ export class PostSummonFormChangeByWeatherAbAttr extends PostSummonAbAttr {
 /**
  * Attribute implementing the effects of {@link https://bulbapedia.bulbagarden.net/wiki/Commander_(Ability) | Commander}.
  * When the source of an ability with this attribute detects a Dondozo as their active ally, the source "jumps
- * into the Dondozo's mouth," sharply boosting the Dondozo's stats, cancelling the source's moves, and
+ * into the Dondozo's mouth"m sharply boosting the Dondozo's stats, cancelling the source's moves, and
  * causing attacks that target the source to always miss.
  */
 export class CommanderAbAttr extends AbAttr {
@@ -8402,7 +8381,8 @@ export function initAbilities() {
       .bypassFaint(),
     new Ability(AbilityId.IMPOSTER, 5)
       .attr(PostSummonTransformAbAttr)
-      .uncopiable(),
+      .uncopiable()
+      .edgeCase(), // Should copy rage fist hit count
     new Ability(AbilityId.INFILTRATOR, 5)
       .attr(InfiltratorAbAttr)
       .partial(), // does not bypass Mist

src/data/moves/move.ts

@@ -7606,19 +7606,23 @@ export class SuppressAbilitiesIfActedAttr extends MoveEffectAttr {
 }
 
 /**
- * Used by Transform
+ * Attribute used to transform into the target on move use.
+ *
+ * Used for {@linkcode MoveId.TRANSFORM}.
  */
 export class TransformAttr extends MoveEffectAttr {
   override apply(user: Pokemon, target: Pokemon, move: Move, args: any[]): boolean {
-    if (!super.apply(user, target, move, args) || (target.isTransformed() || user.isTransformed())) {
+    if (!super.apply(user, target, move, args)) {
-      globalScene.phaseManager.queueMessage(i18next.t("battle:attackFailed"));
       return false;
     }
 
     globalScene.phaseManager.unshiftNew("PokemonTransformPhase", user.getBattlerIndex(), target.getBattlerIndex());
-
     return true;
   }
+
+  getCondition(): MoveConditionFunc {
+    return (user, target) => user.canTransformInto(target)
+  }
 }
 
 /**
@@ -8840,12 +8844,12 @@ export function initMoves() {
       .makesContact(false),
     new StatusMove(MoveId.TRANSFORM, PokemonType.NORMAL, -1, 10, -1, 0, 1)
       .attr(TransformAttr)
-      .condition((user, target, move) => !target.getTag(BattlerTagType.SUBSTITUTE))
-      .condition((user, target, move) => !target.summonData.illusion && !user.summonData.illusion)
-      // transforming from or into fusion pokemon causes various problems (such as crashes)
-      .condition((user, target, move) => !target.getTag(BattlerTagType.SUBSTITUTE) && !user.fusionSpecies && !target.fusionSpecies)
       .ignoresProtect()
-      // Transforming should copy the target's rage fist hit count
+      /* Transform:
+       * Does not copy the target's rage fist hit count
+       * Does not copy the target's volatile status conditions (ie BattlerTags)
+       * Renders user typeless when copying typeless opponent (should revert to original typing)
+      */
       .edgeCase(),
     new AttackMove(MoveId.BUBBLE, PokemonType.WATER, MoveCategory.SPECIAL, 40, 100, 30, 10, 0, 1)
       .attr(StatStageChangeAttr, [ Stat.SPD ], -1)

src/field/pokemon.ts

@@ -1066,6 +1066,30 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     return this.summonData.speciesForm !== null;
   }
 
+  /**
+   * Return whether this Pokemon can transform into an opposing Pokemon.
+   * @param target - The {@linkcode Pokemon} being transformed into.
+   * @returns Whether this Pokemon can transform into `target`.
+   */
+  canTransformInto(target: Pokemon): boolean {
+    return !(
+      // Neither pokemon can be already transformed
+      (
+        this.isTransformed() ||
+        target.isTransformed() ||
+        // Neither pokemon can be behind an illusion
+        target.summonData.illusion ||
+        this.summonData.illusion ||
+        // The target cannot be behind a substitute
+        target.getTag(BattlerTagType.SUBSTITUTE) ||
+        // Transforming to/from fusion pokemon causes various problems (crashes, etc.)
+        // TODO: Consider lifting restriction once bug is fixed
+        this.isFusion() ||
+        target.isFusion()
+      )
+    );
+  }
+
   /**
    * @param {boolean} useIllusion - Whether we want the fusionSpeciesForm of the illusion or not.
    */
@@ -1280,39 +1304,39 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
 
   /**
    * Retrieves the entire set of stats of this {@linkcode Pokemon}.
-   * @param bypassSummonData - whether to use actual stats or in-battle overriden stats from Transform; default `true`
+   * @param bypassSummonData - Whether to prefer actual stats (`true`) or in-battle overridden stats (`false`); default `true`
-   * @returns the numeric values of this {@linkcode Pokemon}'s stats
+   * @returns The numeric values of this {@linkcode Pokemon}'s stats as an array.
    */
   getStats(bypassSummonData = true): number[] {
-    if (!bypassSummonData && this.summonData.stats) {
+    if (!bypassSummonData) {
-      return this.summonData.stats;
+      // Only grab summon data stats if nonzero
+      return this.summonData.stats.map((s, i) => s || this.stats[i]);
     }
     return this.stats;
   }
 
   /**
    * Retrieves the corresponding {@linkcode PermanentStat} of the {@linkcode Pokemon}.
-   * @param stat the desired {@linkcode PermanentStat}
+   * @param stat - The desired {@linkcode PermanentStat}.
-   * @param bypassSummonData prefer actual stats (`true` by default) or in-battle overridden stats (`false`)
+   * @param bypassSummonData - Whether to prefer actual stats (`true`) or in-battle overridden stats (`false`); default `true`
-   * @returns the numeric value of the desired {@linkcode Stat}
+   * @returns The numeric value of the desired {@linkcode Stat}.
    */
   getStat(stat: PermanentStat, bypassSummonData = true): number {
-    if (!bypassSummonData && this.summonData.stats[stat] !== 0) {
+    if (!bypassSummonData) {
-      return this.summonData.stats[stat];
+      // 0 = no override
+      return this.summonData.stats[stat] || this.stats[stat];
     }
     return this.stats[stat];
   }
 
   /**
-   * Writes the value to the corrseponding {@linkcode PermanentStat} of the {@linkcode Pokemon}.
+   * Change one of this {@linkcode Pokemon}'s {@linkcode PermanentStat}s to the specified value.
-   *
+   * @param stat - The {@linkcode PermanentStat} to be overwritten.
-   * Note that this does nothing if {@linkcode value} is less than 0.
+   * @param value - The stat value to set. Ignored if `<=0`
-   * @param stat the desired {@linkcode PermanentStat} to be overwritten
+   * @param bypassSummonData - Whether to write to actual stats (`true`) or in-battle overridden stats (`false`); default `true`
-   * @param value the desired numeric value
-   * @param bypassSummonData write to actual stats (`true` by default) or in-battle overridden stats (`false`)
    */
   setStat(stat: PermanentStat, value: number, bypassSummonData = true): void {
-    if (value < 0) {
+    if (value <= 0) {
       return;
     }
 
@@ -1328,31 +1352,25 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
    * @returns the numeric values of the {@linkcode Pokemon}'s in-battle stat stages if available, a fresh stat stage array otherwise
    */
   getStatStages(): number[] {
-    return this.summonData ? this.summonData.statStages : [0, 0, 0, 0, 0, 0, 0];
+    return this.summonData.statStages;
   }
 
   /**
-   * Retrieves the in-battle stage of the specified {@linkcode BattleStat}.
+   * Retrieve the value of the given stat stage for this {@linkcode Pokemon}.
-   * @param stat the {@linkcode BattleStat} whose stage is desired
+   * @param stat - The {@linkcode BattleStat} to retrieve the stat stage for.
-   * @returns the stage of the desired {@linkcode BattleStat} if available, 0 otherwise
+   * @returns The value of the desired stat stage as a number within the range `[-6, +6]`.
    */
   getStatStage(stat: BattleStat): number {
-    return this.summonData ? this.summonData.statStages[stat - 1] : 0;
+    return this.summonData.statStages[stat - 1];
   }
 
   /**
-   * Writes the value to the in-battle stage of the corresponding {@linkcode BattleStat} of the {@linkcode Pokemon}.
+   * Sets this {@linkcode Pokemon}'s in-battle stat stage to the corresponding value.
-   *
+   * @param stat - The {@linkcode BattleStat} whose stage is to be overwritten.
-   * Note that, if the value is not within a range of [-6, 6], it will be forced to the closest range bound.
+   * @param value - The value of the stat stage to set, forcibly clamped within the range `[-6, +6]`.
-   * @param stat the {@linkcode BattleStat} whose stage is to be overwritten
-   * @param value the desired numeric value
    */
   setStatStage(stat: BattleStat, value: number): void {
-    if (value >= -6) {
+    this.summonData.statStages[stat - 1] = Phaser.Math.Clamp(value, -6, 6);
-      this.summonData.statStages[stat - 1] = Math.min(value, 6);
-    } else {
-      this.summonData.statStages[stat - 1] = Math.max(value, -6);
-    }
   }
 
   /**
@@ -3296,7 +3314,7 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
    * @param onField - whether to also check if the pokemon is currently on the field (defaults to true)
    */
   getOpponents(onField = true): Pokemon[] {
-    return ((this.isPlayer() ? globalScene.getEnemyField() : globalScene.getPlayerField()) as Pokemon[]).filter(p =>
+    return (this.isPlayer() ? globalScene.getEnemyField() : globalScene.getPlayerField()).filter(p =>
       p.isActive(onField),
     );
   }

src/phases/pokemon-transform-phase.ts

@@ -21,12 +21,13 @@ export class PokemonTransformPhase extends PokemonPhase {
     super(userIndex);
 
     this.targetIndex = targetIndex;
+
     this.playSound = playSound;
   }
 
   public override start(): void {
     const user = this.getPokemon();
-    const target = globalScene.getField(true).find(p => p.getBattlerIndex() === this.targetIndex);
+    const target = globalScene.getField()[this.targetIndex];
 
     if (!target) {
       this.end();
@@ -58,6 +59,8 @@ export class PokemonTransformPhase extends PokemonPhase {
       console.warn(`Transform: somehow iterating over a ${m} value when copying moveset!`);
       return new PokemonMove(MoveId.NONE);
     });
+
+    // TODO: This should fallback to the target's original typing if none are left (from Burn Up, etc.)
     user.summonData.types = target.getTypes();
 
     const promises = [user.updateInfo()];