Let's Go: Implement itemless megas (#10212)

data/mods/gen7letsgo/scripts.ts

@@ -4,8 +4,71 @@ export const Scripts: ModdedBattleScriptsData = {
 		this.modData('Abilities', 'noability').isNonstandard = null;
 		for (const i in this.data.Pokedex) {
 			this.modData('Pokedex', i).abilities = {0: 'No Ability'};
+			delete this.modData('Pokedex', i).requiredItem;
 		}
 	},
+	actions: {
+		canMegaEvo(pokemon) {
+			const species = pokemon.baseSpecies;
+			const altForme = this.dex.species.get(species.otherFormes?.find(f => f.endsWith('-Mega')));
+			if (
+				altForme.exists && !this.battle.ruleTable.check(`pokemon:${altForme.id}`) &&
+				!this.battle.ruleTable.check('pokemontag:mega')
+			) {
+				return altForme.name;
+			}
+			return null;
+		},
+		canMegaEvoX(pokemon) {
+			const species = pokemon.baseSpecies;
+			const altForme = this.dex.species.get(species.otherFormes?.find(f => f.endsWith('-Mega-X')));
+			if (
+				altForme.exists && !this.battle.ruleTable.check(`pokemon:${altForme.id}`) &&
+				!this.battle.ruleTable.check('pokemontag:mega')
+			) {
+				return altForme.name;
+			}
+			return null;
+		},
+		canMegaEvoY(pokemon) {
+			const species = pokemon.baseSpecies;
+			const altForme = this.dex.species.get(species.otherFormes?.find(f => f.endsWith('-Mega-Y')));
+			if (
+				altForme.exists && !this.battle.ruleTable.check(`pokemon:${altForme.id}`) &&
+				!this.battle.ruleTable.check('pokemontag:mega')
+			) {
+				return altForme.name;
+			}
+			return null;
+		},
+		runMegaEvo(pokemon) {
+			const speciesid = pokemon.canMegaEvo || pokemon.canMegaEvoX || pokemon.canMegaEvoY;
+			if (!speciesid) return false;
+
+			pokemon.formeChange(speciesid, null, true);
+			this.battle.add('-mega', pokemon, this.dex.species.get(speciesid).baseSpecies);
+
+			// Limit one mega evolution
+			for (const ally of pokemon.side.pokemon) {
+				ally.canMegaEvo = null;
+				ally.canMegaEvoX = null;
+				ally.canMegaEvoY = null;
+			}
+
+			this.battle.runEvent('AfterMega', pokemon);
+			return true;
+		},
+		runMegaEvoX(pokemon) {
+			if (!pokemon.canMegaEvoX) return false;
+			pokemon.canMegaEvoY = null;
+			return this.runMegaEvo(pokemon);
+		},
+		runMegaEvoY(pokemon) {
+			if (!pokemon.canMegaEvoY) return false;
+			pokemon.canMegaEvoX = null;
+			return this.runMegaEvo(pokemon);
+		},
+	},
 	/**
 	 * Given a table of base stats and a pokemon set, return the actual stats.
 	 */

sim/battle-actions.ts

@@ -1896,6 +1896,12 @@ export class BattleActions {
 		return true;
 	}
 
+	// Let's Go
+	canMegaEvoX?: (this: BattleActions, pokemon: Pokemon) => string | null;
+	canMegaEvoY?: (this: BattleActions, pokemon: Pokemon) => string | null;
+	runMegaEvoX?: (this: BattleActions, pokemon: Pokemon) => boolean;
+	runMegaEvoY?: (this: BattleActions, pokemon: Pokemon) => boolean;
+
 	canTerastallize(pokemon: Pokemon) {
 		if (pokemon.getItem().zMove || pokemon.canMegaEvo || this.dex.gen !== 9) {
 			return null;

sim/battle-queue.ts

@@ -92,7 +92,7 @@ export interface FieldAction {
 /** A generic action done by a single pokemon */
 export interface PokemonAction {
 	/** action type */
-	choice: 'megaEvo' | 'shift' | 'runPrimal' | 'runSwitch' | 'event' | 'runUnnerve' | 'runDynamax' | 'terastallize';
+	choice: 'megaEvo' | 'megaEvoX' | 'megaEvoY' | 'shift' | 'runPrimal' | 'runSwitch' | 'event' | 'runUnnerve' | 'runDynamax' | 'terastallize';
 	/** priority of the action (lower first) */
 	priority: number;
 	/** speed of pokemon doing action (higher first if priority tie) */
@@ -179,6 +179,8 @@ export class BattleQueue {
 				runPrimal: 102,
 				switch: 103,
 				megaEvo: 104,
+				megaEvoX: 104,
+				megaEvoY: 104,
 				runDynamax: 105,
 				terastallize: 106,
 				priorityChargeMove: 107,
@@ -210,6 +212,18 @@ export class BattleQueue {
 						pokemon: action.pokemon,
 					}));
 				}
+				if (action.megax && !action.pokemon.isSkyDropped()) {
+					actions.unshift(...this.resolveAction({
+						choice: 'megaEvoX',
+						pokemon: action.pokemon,
+					}));
+				}
+				if (action.megay && !action.pokemon.isSkyDropped()) {
+					actions.unshift(...this.resolveAction({
+						choice: 'megaEvoY',
+						pokemon: action.pokemon,
+					}));
+				}
 				if (action.terastallize && !action.pokemon.terastallized) {
 					actions.unshift(...this.resolveAction({
 						choice: 'terastallize',

sim/battle.ts

@@ -2556,6 +2556,12 @@ export class Battle {
 		case 'megaEvo':
 			this.actions.runMegaEvo(action.pokemon);
 			break;
+		case 'megaEvoX':
+			this.actions.runMegaEvoX?.(action.pokemon);
+			break;
+		case 'megaEvoY':
+			this.actions.runMegaEvoY?.(action.pokemon);
+			break;
 		case 'runDynamax':
 			action.pokemon.addVolatile('dynamax');
 			action.pokemon.side.dynamaxUsed = true;
@@ -2686,7 +2692,7 @@ export class Battle {
 			// in gen 3 or earlier, switching in fainted pokemon is done after
 			// every move, rather than only at the end of the turn.
 			this.checkFainted();
-		} else if (action.choice === 'megaEvo' && this.gen === 7) {
+		} else if (['megaEvo', 'megaEvoX', 'megaEvoY'].includes(action.choice) && this.gen === 7) {
 			this.eachEvent('Update');
 			// In Gen 7, the action order is recalculated for a Pokémon that mega evolves.
 			for (const [i, queuedAction] of this.queue.list.entries()) {

sim/dex-items.ts

@@ -194,10 +194,6 @@ export class DexItems {
 			if (item.gen > this.dex.gen) {
 				(item as any).isNonstandard = 'Future';
 			}
-			// hack for allowing mega evolution in LGPE
-			if (this.dex.currentMod === 'gen7letsgo' && !item.isNonstandard && !item.megaStone) {
-				(item as any).isNonstandard = 'Past';
-			}
 		} else {
 			item = new Item({name: id, exists: false});
 		}

sim/global-types.ts

@@ -219,6 +219,8 @@ interface ModdedBattleActions {
 	afterMoveSecondaryEvent?: (this: BattleActions, targets: Pokemon[], pokemon: Pokemon, move: ActiveMove) => undefined;
 	calcRecoilDamage?: (this: BattleActions, damageDealt: number, move: Move, pokemon: Pokemon) => number;
 	canMegaEvo?: (this: BattleActions, pokemon: Pokemon) => string | undefined | null;
+	canMegaEvoX?: (this: BattleActions, pokemon: Pokemon) => string | null;
+	canMegaEvoY?: (this: BattleActions, pokemon: Pokemon) => string | null;
 	canUltraBurst?: (this: BattleActions, pokemon: Pokemon) => string | null;
 	canZMove?: (this: BattleActions, pokemon: Pokemon) => ZMoveOptions | void;
 	canDynamax?: (this: BattleActions, pokemon: Pokemon, skipChecks?: boolean) => DynamaxOptions | void;
@@ -250,6 +252,8 @@ interface ModdedBattleActions {
 	) => number | undefined | false;
 	runAction?: (this: BattleActions, action: Action) => void;
 	runMegaEvo?: (this: BattleActions, pokemon: Pokemon) => boolean;
+	runMegaEvoX?: (this: BattleActions, pokemon: Pokemon) => boolean;
+	runMegaEvoY?: (this: BattleActions, pokemon: Pokemon) => boolean;
 	runMove?: (
 		this: BattleActions, moveOrMoveName: Move | string, pokemon: Pokemon, targetLoc: number, sourceEffect?: Effect | null,
 		zMove?: string, externalMove?: boolean, maxMove?: string, originalTarget?: Pokemon

sim/pokemon.ts

@@ -253,6 +253,8 @@ export class Pokemon {
 	abilityOrder: number;
 
 	canMegaEvo: string | null | undefined;
+	canMegaEvoX: string | null | undefined;
+	canMegaEvoY: string | null | undefined;
 	canUltraBurst: string | null | undefined;
 	readonly canGigantamax: string | null;
 	/**
@@ -468,6 +470,8 @@ export class Pokemon {
 		this.abilityOrder = 0;
 
 		this.canMegaEvo = this.battle.actions.canMegaEvo(this);
+		this.canMegaEvoX = this.battle.actions.canMegaEvoX?.(this);
+		this.canMegaEvoY = this.battle.actions.canMegaEvoY?.(this);
 		this.canUltraBurst = this.battle.actions.canUltraBurst(this);
 		this.canGigantamax = this.baseSpecies.canGigantamax || null;
 		this.canTerastallize = this.battle.actions.canTerastallize(this);
@@ -1043,6 +1047,8 @@ export class Pokemon {
 			trapped?: boolean,
 			maybeTrapped?: boolean,
 			canMegaEvo?: boolean,
+			canMegaEvoX?: boolean,
+			canMegaEvoY?: boolean,
 			canUltraBurst?: boolean,
 			canZMove?: AnyObject | null,
 			canDynamax?: boolean,
@@ -1070,6 +1076,8 @@ export class Pokemon {
 
 		if (!lockedMove) {
 			if (this.canMegaEvo) data.canMegaEvo = true;
+			if (this.canMegaEvoX) data.canMegaEvoX = true;
+			if (this.canMegaEvoY) data.canMegaEvoY = true;
 			if (this.canUltraBurst) data.canUltraBurst = true;
 			const canZMove = this.battle.actions.canZMove(this);
 			if (canZMove) data.canZMove = canZMove;

sim/side.ts

@@ -36,6 +36,8 @@ export interface ChosenAction {
 	index?: number; // the chosen index in Team Preview
 	side?: Side; // the action's side
 	mega?: boolean | null; // true if megaing or ultra bursting
+	megax?: boolean | null; // true if megaing x
+	megay?: boolean | null; // true if megaing y
 	zmove?: string; // if zmoving, the name of the zmove
 	maxMove?: string; // if dynamaxed, the name of the max move
 	terastallize?: string; // if terastallizing, tera type
@@ -408,7 +410,7 @@ export class Side {
 	chooseMove(
 		moveText?: string | number,
 		targetLoc = 0,
-		event: 'mega' | 'zmove' | 'ultra' | 'dynamax' | 'terastallize' | '' = ''
+		event: 'mega' | 'megax' | 'megay' | 'zmove' | 'ultra' | 'dynamax' | 'terastallize' | '' = ''
 	) {
 		if (this.requestState !== 'move') {
 			return this.emitChoiceError(`Can't move: You need a ${this.requestState} response`);
@@ -591,10 +593,18 @@ export class Side {
 		// Mega evolution
 
 		const mega = (event === 'mega');
+		const megax = (event === 'megax');
+		const megay = (event === 'megay');
 		if (mega && !pokemon.canMegaEvo) {
 			return this.emitChoiceError(`Can't move: ${pokemon.name} can't mega evolve`);
 		}
-		if (mega && this.choice.mega) {
+		if (megax && !pokemon.canMegaEvoX) {
+			return this.emitChoiceError(`Can't move: ${pokemon.name} can't mega evolve X`);
+		}
+		if (megay && !pokemon.canMegaEvoY) {
+			return this.emitChoiceError(`Can't move: ${pokemon.name} can't mega evolve Y`);
+		}
+		if ((mega || megax || megay) && this.choice.mega) {
 			return this.emitChoiceError(`Can't move: You can only mega-evolve once per battle`);
 		}
 		const ultra = (event === 'ultra');
@@ -639,6 +649,8 @@ export class Side {
 			targetLoc,
 			moveid,
 			mega: mega || ultra,
+			megax: megax,
+			megay: megay,
 			zmove: zMove,
 			maxMove: maxMove ? maxMove.id : undefined,
 			terastallize: terastallize ? pokemon.teraType : undefined,
@@ -648,7 +660,7 @@ export class Side {
 			this.choice.cantUndo = this.choice.cantUndo || pokemon.isLastActive();
 		}
 
-		if (mega) this.choice.mega = true;
+		if (mega || megax || megay) this.choice.mega = true;
 		if (ultra) this.choice.ultra = true;
 		if (zMove) this.choice.zMove = true;
 		if (dynamax) this.choice.dynamax = true;
@@ -939,7 +951,7 @@ export class Side {
 				const original = data;
 				const error = () => this.emitChoiceError(`Conflicting arguments for "move": ${original}`);
 				let targetLoc: number | undefined;
-				let event: 'mega' | 'zmove' | 'ultra' | 'dynamax' | 'terastallize' | '' = '';
+				let event: 'mega' | 'megax' | 'megay' | 'zmove' | 'ultra' | 'dynamax' | 'terastallize' | '' = '';
 				while (true) {
 					// If data ends with a number, treat it as a target location.
 					// We need to special case 'Conversion 2' so it doesn't get
@@ -953,6 +965,14 @@ export class Side {
 						if (event) return error();
 						event = 'mega';
 						data = data.slice(0, -5);
+					} else if (data.endsWith(' megax')) {
+						if (event) return error();
+						event = 'megax';
+						data = data.slice(0, -6);
+					} else if (data.endsWith(' megay')) {
+						if (event) return error();
+						event = 'megay';
+						data = data.slice(0, -6);
 					} else if (data.endsWith(' zmove')) {
 						if (event) return error();
 						event = 'zmove';

sim/team-validator.ts

@@ -682,7 +682,7 @@ export class TeamValidator {
 			if (dex.gen === 4 && item.id === 'griseousorb' && species.num !== 487) {
 				problems.push(`${set.name} cannot hold the Griseous Orb.`, `(In Gen 4, only Giratina could hold the Griseous Orb).`);
 			}
-			if (dex.gen <= 1) {
+			if (dex.gen <= 1 || dex.currentMod === 'gen7letsgo') {
 				if (item.id) {
 					// no items allowed
 					set.item = '';