[Bug] Fix #762: All Pokemon become invisible when capturing then switching with your only pokemon that was not fainted (#4025)

* fix #762 by using slotIndex to add to party

for now the new pokemon was ALWAYS just pushed to the party array. Now it's put into the slot that was also previously selected as the mon to release

* add docs for `Pokemon.addToParty()`

* add simple tests for addToParty

* update `isBetween` docs. Remove `.js` imports

src/constants.ts

@@ -0,0 +1 @@
+export const PLAYER_PARTY_MAX_SIZE = 6;

src/field/pokemon.ts

@@ -58,6 +58,7 @@ import { StatStageChangePhase } from "#app/phases/stat-stage-change-phase";
 import { SwitchSummonPhase } from "#app/phases/switch-summon-phase";
 import { ToggleDoublePositionPhase } from "#app/phases/toggle-double-position-phase";
 import { Challenges } from "#enums/challenges";
+import { PLAYER_PARTY_MAX_SIZE } from "#app/constants";
 
 export enum FieldPosition {
   CENTER,
@@ -4465,17 +4466,29 @@ export class EnemyPokemon extends Pokemon {
     return BattlerIndex.ENEMY + this.getFieldIndex();
   }
 
-  addToParty(pokeballType: PokeballType) {
+  /**
+   * Add a new pokemon to the player's party (at `slotIndex` if set).
+   * @param pokeballType the type of pokeball the pokemon was caught with
+   * @param slotIndex an optional index to place the pokemon in the party
+   * @returns the pokemon that was added or null if the pokemon could not be added
+   */
+  addToParty(pokeballType: PokeballType, slotIndex: number = -1) {
     const party = this.scene.getParty();
     let ret: PlayerPokemon | null = null;
 
-    if (party.length < 6) {
+    if (party.length < PLAYER_PARTY_MAX_SIZE) {
       this.pokeball = pokeballType;
       this.metLevel = this.level;
       this.metBiome = this.scene.arena.biomeType;
       this.metSpecies = this.species.speciesId;
       const newPokemon = this.scene.addPlayerPokemon(this.species, this.level, this.abilityIndex, this.formIndex, this.gender, this.shiny, this.variant, this.ivs, this.nature, this);
+
+      if (Utils.isBetween(slotIndex, 0, PLAYER_PARTY_MAX_SIZE - 1)) {
+        party.splice(slotIndex, 0, newPokemon);
+      } else {
         party.push(newPokemon);
+      }
+
       ret = newPokemon;
       this.scene.triggerPokemonFormChange(newPokemon, SpeciesFormChangeActiveTrigger, true);
     }

src/phases/attempt-capture-phase.ts

@@ -221,8 +221,8 @@ export class AttemptCapturePhase extends PokemonPhase {
         this.scene.clearEnemyHeldItemModifiers();
         this.scene.field.remove(pokemon, true);
       };
-      const addToParty = () => {
-        const newPokemon = pokemon.addToParty(this.pokeballType);
+      const addToParty = (slotIndex?: number) => {
+        const newPokemon = pokemon.addToParty(this.pokeballType, slotIndex);
         const modifiers = this.scene.findModifiers(m => m instanceof PokemonHeldItemModifier, false);
         if (this.scene.getParty().filter(p => p.isShiny()).length === 6) {
           this.scene.validateAchv(achvs.SHINY_PARTY);
@@ -253,7 +253,7 @@ export class AttemptCapturePhase extends PokemonPhase {
                 this.scene.ui.setMode(Mode.PARTY, PartyUiMode.RELEASE, this.fieldIndex, (slotIndex: integer, _option: PartyOption) => {
                   this.scene.ui.setMode(Mode.MESSAGE).then(() => {
                     if (slotIndex < 6) {
-                      addToParty();
+                      addToParty(slotIndex);
                     } else {
                       promptRelease();
                     }

src/test/field/pokemon.test.ts

@@ -1,6 +1,8 @@
 import { Species } from "#app/enums/species";
 import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
 import GameManager from "../utils/gameManager";
+import { PokeballType } from "#app/enums/pokeball";
+import BattleScene from "#app/battle-scene";
 
 describe("Spec - Pokemon", () => {
   let phaserGame: Phaser.Game;
@@ -28,4 +30,37 @@ describe("Spec - Pokemon", () => {
 
     expect(pkm.trySetStatus(undefined)).toBe(true);
   });
+
+  describe("Add To Party", () => {
+    let scene: BattleScene;
+
+    beforeEach(async () => {
+      game.override.enemySpecies(Species.ZUBAT);
+      await game.classicMode.runToSummon([Species.ABRA, Species.ABRA, Species.ABRA, Species.ABRA, Species.ABRA]); // 5 Abra, only 1 slot left
+      scene = game.scene;
+    });
+
+    it("should append a new pokemon by default", async () => {
+      const zubat = scene.getEnemyPokemon()!;
+      zubat.addToParty(PokeballType.LUXURY_BALL);
+
+      const party = scene.getParty();
+      expect(party).toHaveLength(6);
+      party.forEach((pkm, index) =>{
+        expect(pkm.species.speciesId).toBe(index === 5 ? Species.ZUBAT : Species.ABRA);
+      });
+    });
+
+    it("should put a new pokemon into the passed slotIndex", async () => {
+      const slotIndex = 1;
+      const zubat = scene.getEnemyPokemon()!;
+      zubat.addToParty(PokeballType.LUXURY_BALL, slotIndex);
+
+      const party = scene.getParty();
+      expect(party).toHaveLength(6);
+      party.forEach((pkm, index) =>{
+        expect(pkm.species.speciesId).toBe(index === slotIndex ? Species.ZUBAT : Species.ABRA);
+      });
+    });
+  });
 });

src/utils.ts

@@ -609,3 +609,14 @@ export function toDmgValue(value: number, minValue: number = 1) {
 export function getLocalizedSpriteKey(baseKey: string) {
   return `${baseKey}${verifyLang(i18next.resolvedLanguage) ? `_${i18next.resolvedLanguage}` : ""}`;
 }
+
+/**
+ * Check if a number is **inclusive** between two numbers
+ * @param num the number to check
+ * @param min the minimum value (included)
+ * @param max the maximum value (included)
+ * @returns true if number is **inclusive** between min and max
+ */
+export function isBetween(num: number, min: number, max: number): boolean {
+  return num >= min && num <= max;
+}