[Bug][Hotfix] Fix fusion with dual type + monotype with shared primary type. (#5322)

* Fix fusion with dual type + monotype with shared primary type.

* Update version number

* Add test case

package-lock.json

@@ -1,12 +1,12 @@
 {
 	"name": "pokemon-rogue-battle",
-	"version": "1.6.2",
+	"version": "1.6.3",
 	"lockfileVersion": 3,
 	"requires": true,
 	"packages": {
 		"": {
 			"name": "pokemon-rogue-battle",
-			"version": "1.5.4",
+			"version": "1.6.3",
 			"hasInstallScript": true,
 			"dependencies": {
 				"@material/material-color-utilities": "^0.2.7",

package.json

@@ -1,7 +1,7 @@
 {
 	"name": "pokemon-rogue-battle",
 	"private": true,
-	"version": "1.6.2",
+	"version": "1.6.3",
 	"type": "module",
 	"scripts": {
 		"start": "vite",

src/field/pokemon.ts

@@ -1322,6 +1322,12 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
           } else if (fusionType1 !== types[0]) {
             secondType = fusionType1;
           }
+
+
+          if (secondType === Type.UNKNOWN && Utils.isNullOrUndefined(fusionType2)) { // If second pokemon was monotype and shared its primary type
+            secondType = (customTypes && this.customPokemonData.types.length > 1 && this.customPokemonData.types[1] !== Type.UNKNOWN)
+              ? this.customPokemonData.types[1] : (speciesForm.type2 ?? Type.UNKNOWN);
+          }
         } else {
           // If not a fusion, just get the second type from the species, checking for permanent changes from ME
           secondType = (customTypes && this.customPokemonData.types.length > 1 && this.customPokemonData.types[1] !== Type.UNKNOWN)

src/test/field/pokemon.test.ts

@@ -150,6 +150,17 @@ describe("Spec - Pokemon", () => {
       expect(types[1]).toBe(Type.DARK);
     });
 
+    it("Fusing mons with two and one types", async () => {
+      game.override.starterSpecies(Species.NUMEL);
+      game.override.starterFusionSpecies(Species.CHARMANDER);
+      await game.classicMode.startBattle();
+      const pokemon = scene.getPlayerParty()[0];
+
+      const types = pokemon.getTypes();
+      expect(types[0]).toBe(Type.FIRE);
+      expect(types[1]).toBe(Type.GROUND);
+    });
+
     it("Fusing two mons with two types", async () => {
       game.override.starterSpecies(Species.NATU);
       game.override.starterFusionSpecies(Species.HOUNDOUR);