Implementation of Destiny Bond

src/data/battler-tags.ts

@@ -254,6 +254,25 @@ export class ConfusedTag extends BattlerTag {
   }
 }
 
+export class DestinyBondTag extends BattlerTag {
+  constructor(sourceMove: Moves, sourceId: integer) {
+    super(BattlerTagType.DESTINY_BOND, BattlerTagLapseType.PRE_MOVE, 1, sourceMove, sourceId);
+  }
+
+  lapse(pokemon: Pokemon, lapseType: BattlerTagLapseType): boolean {
+    if (lapseType !== BattlerTagLapseType.CUSTOM) {
+      return super.lapse(pokemon, lapseType);
+    }
+    const source = pokemon.scene.getPokemonById(this.sourceId);
+    if (source.isFainted()) {
+      const targetMessage = getPokemonMessage(pokemon, '');
+      pokemon.scene.queueMessage(`${getPokemonMessage(source, ` took\n${targetMessage} down with it!`)}`)
+      pokemon.damageAndUpdate(pokemon.hp, HitResult.ONE_HIT_KO, false, false, true);
+    }
+    return false;
+  }
+}
+
 export class InfatuatedTag extends BattlerTag {
   constructor(sourceMove: integer, sourceId: integer) {
     super(BattlerTagType.INFATUATED, BattlerTagLapseType.MOVE, 1, sourceMove, sourceId);
@@ -1405,6 +1424,8 @@ export function getBattlerTag(tagType: BattlerTagType, turnCount: integer, sourc
       return new MagnetRisenTag(tagType, sourceMove);
     case BattlerTagType.MINIMIZED:
       return new MinimizeTag();
+    case BattlerTagType.DESTINY_BOND:
+      return new DestinyBondTag(sourceMove, sourceId);
     case BattlerTagType.NONE:
     default:
         return new BattlerTag(tagType, BattlerTagLapseType.CUSTOM, turnCount, sourceMove, sourceId);

src/data/enums/battler-tag-type.ts

@@ -56,5 +56,6 @@ export enum BattlerTagType {
   CHARGED = "CHARGED",
   GROUNDED = "GROUNDED",
   MAGNET_RISEN = "MAGNET_RISEN",
-  MINIMIZED = "MINIMIZED"
+  MINIMIZED = "MINIMIZED",
+  DESTINY_BOND = "DESTINY_BOND"
 }

src/data/move.ts

@@ -4250,6 +4250,18 @@ export class MoneyAttr extends MoveEffectAttr {
   }
 }
 
+export class DestinyBondAttr extends MoveEffectAttr {
+  constructor() {
+    super(true, MoveEffectTrigger.PRE_APPLY);
+  }
+
+  apply(user: Pokemon, target: Pokemon, move: Move, args: any[]): boolean {
+    user.scene.queueMessage(`${getPokemonMessage(user, ' is trying\nto take its foe down with it!')}`);
+    target.addTag(BattlerTagType.DESTINY_BOND, undefined, move.id, user.id);
+    return true;
+  }
+}
+
 export class LastResortAttr extends MoveAttr {
   getCondition(): MoveConditionFunc {
     return (user: Pokemon, target: Pokemon, move: Move) => {
@@ -4944,8 +4956,8 @@ export function initMoves() {
       .unimplemented(),
     new SelfStatusMove(Moves.DESTINY_BOND, Type.GHOST, -1, 5, -1, 0, 2)
       .ignoresProtect()
-      .condition(failOnBossCondition)
+      .attr(DestinyBondAttr)
-      .unimplemented(),
+      .condition(failOnBossCondition),
     new StatusMove(Moves.PERISH_SONG, Type.NORMAL, -1, 5, -1, 0, 2)
       .attr(FaintCountdownAttr)
       .ignoresProtect()

src/field/pokemon.ts

@@ -1610,6 +1610,9 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
 
           console.log('damage', damage.value, move.name, power.value, sourceAtk, targetDef);
 
+          // In case of fatal damage, this tag would have gotten cleared before we could lapse it.
+          const destinyTag = this.getTag(BattlerTagType.DESTINY_BOND);
+
           if (damage.value) {
             if (this.getHpRatio() === 1)
               applyPreDefendAbAttrs(PreDefendFullHpEndureAbAttr, this, source, battlerMove, cancelled, damage);
@@ -1655,8 +1658,12 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
             }
           }
 
-          if (damage)
+          if (damage) {
             this.scene.clearPhaseQueueSplice();
+
+            const attacker = this.scene.getPokemonById(source.id);
+            destinyTag?.lapse(attacker, BattlerTagLapseType.CUSTOM);
+          }
         }
         break;
       case MoveCategory.STATUS: