Implement Beat Up

src/data/move.ts

@@ -804,6 +804,7 @@ export enum MultiHitType {
   _3,
   _3_INCR,
   _1_TO_10,
+  BEAT_UP,
 }
 
 export class HealAttr extends MoveEffectAttr {
@@ -1069,6 +1070,11 @@ export class MultiHitAttr extends MoveAttr {
             hitTimes = 10;
         }
         break;
+      case MultiHitType.BEAT_UP:
+        // No status means the ally pokemon can contribute to Beat Up
+        hitTimes = user.scene.getParty().reduce((total, pokemon) => {
+          return total + (pokemon.id === user.id ? 1 : pokemon?.status && pokemon.status.effect !== StatusEffect.NONE ? 0 : 1)
+        }, 0);
     }
     (args[0] as Utils.IntegerHolder).value = hitTimes;
     return true;
@@ -1866,6 +1872,45 @@ export class MovePowerMultiplierAttr extends VariablePowerAttr {
   }
 }
 
+/**
+ * Helper function to calculate the the base power of an ally's hit when using Beat Up.
+ * @param user The Pokemon that used Beat Up.
+ * @param allyIndex The party position of the ally contributing to Beat Up.
+ * @returns The base power of the Beat Up hit.
+ */
+const beatUpFunc = (user: Pokemon, allyIndex: number): number => {
+  const party = user.scene.getParty();
+
+  for (let i = allyIndex; i < party.length; i++) {
+    const pokemon = party[i];
+
+    // The user contributes to Beat Up regardless of status condition.
+    // Allies can contribute only if they do not have a non-volatile status condition.
+    if (pokemon.id !== user.id && pokemon?.status && pokemon.status.effect !== StatusEffect.NONE) {
+      continue;
+    }
+    return (pokemon.species.getBaseStat(Stat.ATK) / 10) + 5;
+  }
+}
+
+export class BeatUpAttr extends VariablePowerAttr {
+
+  /**
+   * Gets the next party member to contribute to a Beat Up hit, and calculates the base power for it.
+   * @param user Pokemon that used the move
+   * @param _target N/A
+   * @param _move Move with this attribute
+   * @param args N/A
+   * @returns true if the function succeeds
+   */
+  apply(user: Pokemon, target: Pokemon, move: Move, args: any[]): boolean {
+    const power = args[0] as Utils.NumberHolder;
+    const allyIndex = user.turnData.hitCount - user.turnData.hitsLeft;
+    power.value = beatUpFunc(user, allyIndex);
+    return true;
+  }
+}
+
 const doublePowerChanceMessageFunc = (user: Pokemon, target: Pokemon, move: Move) => {
   let message: string = null;
   user.scene.executeWithSeedOffset(() => {
@@ -4831,8 +4876,9 @@ export function initMoves() {
       .attr(TrapAttr, BattlerTagType.WHIRLPOOL)
       .attr(HitsTagAttr, BattlerTagType.UNDERWATER, true),
     new AttackMove(Moves.BEAT_UP, Type.DARK, MoveCategory.PHYSICAL, -1, 100, 10, -1, 0, 2)
-      .makesContact(false)
-      .unimplemented(),
+      .attr(MultiHitAttr, MultiHitType.BEAT_UP)
+      .attr(BeatUpAttr)
+      .makesContact(false),
     new AttackMove(Moves.FAKE_OUT, Type.NORMAL, MoveCategory.PHYSICAL, 40, 100, 10, 100, 3, 3)
       .attr(FlinchAttr)
       .condition(new FirstMoveCondition()),

src/data/pokemon-species.ts

@@ -16,6 +16,7 @@ import { GameMode } from '../game-mode';
 import { QuantizerCelebi, argbFromRgba, rgbaFromArgb } from "@material/material-color-utilities";
 import { VariantSet } from './variant';
 import i18next, { Localizable } from '../plugins/i18n';
+import { Stat } from "./pokemon-stat";
 
 export enum Region {
   NORMAL,
@@ -192,6 +193,15 @@ export abstract class PokemonSpeciesForm {
     return false;
   }
 
+  /**
+   * Gets the species' base stat amount for the given stat.
+   * @param stat  The desired stat.
+   * @returns The species' base stat amount.
+   */
+  getBaseStat(stat: Stat): integer {
+    return this.baseStats[stat]
+  }
+
   getBaseExp(): integer {
     let ret = this.baseExp;
     switch (this.getFormSpriteKey()) {