Implement Dancer using the battle queue and the AnyAfterMove event

data/abilities.ts

@@ -827,7 +827,46 @@ export const Abilities: import('../sim/dex-abilities').AbilityDataTable = {
 	dancer: {
 		flags: {},
 		name: "Dancer",
-		// implemented in runMove in scripts.js
+		onAnyAfterMovePriority: -200,
+		onAnyAfterMove(source, target, move) {
+			const dancer = this.effectState.target as Pokemon;
+			if (dancer === source || dancer.isSemiInvulnerable() || !move.flags['dance'] ||
+				!this.lastSuccessfulMoveThisTurn || move.isExternal) return;
+			const targetOf1stDance = this.activeTarget!;
+			dancer.addVolatile('dancer');
+			const dancersTarget = !targetOf1stDance.isAlly(dancer) && source.isAlly(dancer) ?
+				targetOf1stDance : source;
+			const dancersTargetLoc = dancer.getLocOf(dancersTarget);
+			// Dancer activates in order of lowest speed stat to highest
+			// Note that the speed stat used is after any volatile replacements like Speed Swap,
+			// but before any multipliers like Agility or Choice Scarf
+			// Ties go to whichever Pokemon has had the ability for the least amount of time
+			this.queue.insertChoice({
+				choice: 'move',
+				order: 198 + dancer.storedStats['spe'] / 100000, // FIXME HACK
+				speed: -source.storedStats['spe'], // speed gets reset
+				effectOrder: dancer.abilityState.effectOrder,
+				pokemon: dancer,
+				moveid: move.id,
+				targetLoc: dancersTargetLoc,
+				sourceEffect: this.dex.abilities.get('dancer'),
+				externalMove: true,
+			});
+		},
+		condition: {
+			noCopy: true, // doesn't get copied by Baton Pass
+			onBeforeMovePriority: 200,
+			onBeforeMove(source, target, move) {
+				this.add('-activate', source, 'ability: Dancer');
+				this.effectState.noLock = move.isExternal && !source.volatiles['lockedmove'];
+			},
+			onTryAddVolatile(status) {
+				if (status.id === 'lockedmove' && this.effectState.noLock) return null;
+			},
+			onAfterMove(source) {
+				delete source.volatiles['dancer'];
+			},
+		},
 		rating: 1.5,
 		num: 216,
 	},

sim/battle-actions.ts

@@ -290,10 +290,6 @@ export class BattleActions {
 			pokemon.moveUsed(move, targetLoc);
 		}
 
-		// Dancer Petal Dance hack
-		// TODO: implement properly
-		const noLock = externalMove && !pokemon.volatiles['lockedmove'];
-
 		if (zMove) {
 			if (pokemon.illusion) {
 				this.battle.singleEvent('End', this.dex.abilities.get('Illusion'), pokemon.abilityState, pokemon);
@@ -313,36 +309,6 @@ export class BattleActions {
 			this.battle.add('-hint', `Some effects can force a Pokemon to use ${move.name} again in a row.`);
 		}
 
-		// TODO: Refactor to use BattleQueue#prioritizeAction in onAnyAfterMove handlers
-		// Dancer's activation order is completely different from any other event, so it's handled separately
-		if (move.flags['dance'] && moveDidSomething && !move.isExternal) {
-			const dancers = [];
-			for (const currentPoke of this.battle.getAllActive()) {
-				if (pokemon === currentPoke) continue;
-				if (currentPoke.hasAbility('dancer') && !currentPoke.isSemiInvulnerable()) {
-					dancers.push(currentPoke);
-				}
-			}
-			// Dancer activates in order of lowest speed stat to highest
-			// Note that the speed stat used is after any volatile replacements like Speed Swap,
-			// but before any multipliers like Agility or Choice Scarf
-			// Ties go to whichever Pokemon has had the ability for the least amount of time
-			dancers.sort(
-				(a, b) => -(b.storedStats['spe'] - a.storedStats['spe']) || b.abilityState.effectOrder - a.abilityState.effectOrder
-			);
-			const targetOf1stDance = this.battle.activeTarget!;
-			for (const dancer of dancers) {
-				if (this.battle.faintMessages()) break;
-				if (dancer.fainted) continue;
-				this.battle.add('-activate', dancer, 'ability: Dancer');
-				const dancersTarget = !targetOf1stDance.isAlly(dancer) && pokemon.isAlly(dancer) ?
-					targetOf1stDance :
-					pokemon;
-				const dancersTargetLoc = dancer.getLocOf(dancersTarget);
-				this.runMove(move.id, dancer, dancersTargetLoc, { sourceEffect: this.dex.abilities.get('dancer'), externalMove: true });
-			}
-		}
-		if (noLock && pokemon.volatiles['lockedmove']) delete pokemon.volatiles['lockedmove'];
 		this.battle.faintMessages();
 		this.battle.checkWin();
 

sim/battle-queue.ts

@@ -19,7 +19,7 @@ import type { Battle } from './battle';
 export interface MoveAction {
 	/** action type */
 	choice: 'move' | 'beforeTurnMove' | 'priorityChargeMove';
-	order: 3 | 5 | 200 | 201 | 199 | 106;
+	order: 3 | 5 | 107 | 198 | 199 | 200 | 201;
 	/** priority of the action (lower first) */
 	priority: number;
 	/** fractional priority of the action (lower first) */
@@ -44,6 +44,8 @@ export interface MoveAction {
 	maxMove?: string;
 	/** effect that called the move (eg Instruct) if any */
 	sourceEffect?: Effect | null;
+	/** if external, skips LockMove and PP deduction, mostly for use by Dancer */
+	externalMove?: boolean;
 }
 
 /** A switch action */

sim/battle.ts

@@ -2682,7 +2682,7 @@ export class Battle {
 			if (!action.pokemon.isActive) return false;
 			if (action.pokemon.fainted) return false;
 			this.actions.runMove(action.move, action.pokemon, action.targetLoc, {
-				sourceEffect: action.sourceEffect, zMove: action.zmove,
+				sourceEffect: action.sourceEffect, zMove: action.zmove, externalMove: action.externalMove,
 				maxMove: action.maxMove, originalTarget: action.originalTarget,
 			});
 			break;

sim/dex-conditions.ts

@@ -427,6 +427,7 @@ export interface EventMethods {
 	onAfterMoveSecondarySelfPriority?: number;
 	onAfterMoveSelfPriority?: number;
 	onAfterSetStatusPriority?: number;
+	onAnyAfterMovePriority?: number;
 	onAnyBasePowerPriority?: number;
 	onAnyInvulnerabilityPriority?: number;
 	onAnyModifyAccuracyPriority?: number;

test/sim/abilities/dancer.js

@@ -183,4 +183,19 @@ describe('Dancer', () => {
 		assert.equal(fletchinder.boosts.atk, -2);
 		assert.equal(squawkabilly.boosts.atk, -4);
 	});
+
+	it('should activate after Eject Button', () => {
+		battle = common.createBattle({ gameType: 'doubles' }, [[
+			{ species: 'oricoriopau', ability: 'dancer', moves: ['sleeptalk'] },
+			{ species: 'volcarona', moves: ['fierydance'] },
+		], [
+			{ species: 'fletchinder', item: 'ejectbutton', moves: ['sleeptalk'] },
+			{ species: 'squawkabilly', moves: ['sleeptalk'] },
+			{ species: 'suicune', moves: ['sleeptalk'] },
+		]]);
+		const suicune = battle.p2.pokemon[2];
+		battle.makeChoices('move sleeptalk, move fierydance 1', 'move sleeptalk, move sleeptalk');
+		battle.makeChoices();
+		assert.notEqual(suicune.hp, suicune.fullHP);
+	});
 });